Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Chevron Long Wharf Maintenance and Efficiency Program in San Francisco Bay, California, 19247-19267 [2023-06744]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 62 (Friday, March 31, 2023)]
[Notices]
[Pages 19247-19267]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-06744]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC798]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Chevron Long Wharf Maintenance 
and Efficiency Program 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

[[Page 19248]]

comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from Chevron Products Company for 
authorization to take marine mammals incidental to the Long Wharf 
Maintenance and Efficiency Program (LWMEP) 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 is also requesting comments on a 
possible one-time, one-year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorization and agency responses will be 
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than May 1, 
2023.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email 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, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at 
www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act 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: Jessica Taylor, 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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems 
accessing these documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. 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 proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

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 IHA) 
with respect to potential impacts on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (IHAs 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 December 16, 2022, NMFS received a request from Chevron Products 
Company (Chevron) for an IHA to take marine mammals incidental to pile 
driving activities associated with the LWMEP in San Francisco Bay (the 
Bay), California. Following NMFS' review of the application, Chevron 
submitted a final revised version on February 27, 2023. The application 
was deemed adequate and complete on March 20, 2023. Chevron's request 
is for take of 7 species of marine mammals by Level B harassment only. 
Neither Chevron nor NMFS expect serious injury or mortality to result 
from this activity and, therefore, an IHA is appropriate.
    NMFS previously issued IHAs to Chevron for similar work (83 FR 
27548, June 13, 2018; 84 FR 28474, June 19, 2019; 85 FR 37064, June 19, 
2020; 86 FR 28578, May 27, 2021; 87 FR 35180, June 9, 2022). Chevron 
complied with all the requirements (e.g., mitigation, monitoring, and 
reporting) of the previous IHAs and information regarding their 
monitoring results may be found in the Estimated Take section.
    This proposed IHA would cover 1 year of a larger project for which 
Chevron obtained prior IHAs and intends to request take authorization 
for subsequent facets of the project. The larger 5-year project 
involves upgrading Long Wharf to satisfy current Marine Oil Terminal 
Engineering and Maintenance Standards.

Description of Proposed Activity

Overview

    Chevron plans to upgrade Berth 1 of the Refinery Long Wharf in the 
Bay, California in order to meet current safety and efficiency 
standards. As part of the proposed project, Chevron is proposing to use 
vibratory extraction to remove concrete piles associated with the 
existing gangway and catwalk. Impact hammers would be used to install 
concrete piles to construct a mooring dolphin and hook, breasting 
dolphin and breasting points with standoff fenders, and to replace the 
catwalk in a different location. A temporary construction template 
composed of steel piles would be installed through the use of a 
vibratory hammer and removed by vibratory extraction when in-water 
construction activities are complete. The Long Wharf

[[Page 19249]]

has six berths for receiving raw materials and shipping products. The 
project area encompasses the entirety of Berth 1, an area of 
approximately 470 square meters (m\2\). All in-water work would take 
place within the seasonal work window of June 1, 2023 through November 
30, 2023.
    Chevron's proposed activity includes impact and vibratory pile 
driving and vibratory pile removal, which may result in the incidental 
take of marine mammals, by harassment only. Due to mitigation measures, 
no Level A harassment is anticipated to occur, and none is proposed for 
authorization.

Dates and Duration

    In-water construction activities would occur over the course of 30 
days from June 1, 2023 through November 30, 2023. Chevron states that 
it would conduct work only in daylight hours. The proposed in-water 
work schedule is shown in table 1. In-water work would begin with of 1 
day of vibratory pile extraction, then 21 days of impact pile 
installation. The temporary construction trestle would require 4 days 
of vibratory pile installation and 4 days of vibratory pile removal. 
Pile installation and removal would occur at a rate 2-3 piles per day, 
depending upon pile size and type. Only one pile would be driven or 
extracted at a time. Although the IHA would be active for a period of 1 
year, in-water pile installation and removal activities are planned 
from June through November to protect sensitive life stages of listed 
fish species in the area.

                                                         Table 1--In-Water Construction Schedule
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                                                                                                             Estimated
                                                                                             Estimated     duration per
                 Pile type                             Method                Number of      strikes per       pile in        Estimated         Total
                                                                               piles           pile           minutes     number per day  estimated days
                                                                                                             (seconds)
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24-inch square concrete pile..............  Impact install..............              42         440 \1\       20 (1200)               2              21
36-inch steel shell pile \2\..............  Vibratory install...........              12             N/A        10 (600)               3               4
18-inch concrete pile.....................  Vibratory extract...........               2             N/A      6.67 (400)               2               1
36-inch steel shell pile \2\..............  Vibratory extract...........              12             N/A        10 (600)               3               4
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\1\ Using a DelMag D62 22 or similar diesel hammer.
\2\ Temporary template.

Specific Geographic Region

    The Long Wharf is located in northern region of the central Bay, 
south of the eastern terminus of the Richmond-San Rafael Bridge (RSRB) 
(Figure 1). Water depth in the project area ranges from approximately 6 
to 15 meters (m), mean lower low water (MLLW). The substrate is 
primarily Bay mud, however, sand or gravel may exist deeper into the 
substrate. The project area around Berth 1 is approximately 470 square 
kilometers (km\2\) in size. Ambient underwater noise in the vicinity of 
the project area is generated by shipping activity, ferry traffic, and 
sound generated by the Richmond Bridge piers. Underwater noise 
measurements in 2006 and from 2020-2022 found the ambient noise in the 
project area to exceed 120 dB RMS. Ambient underwater noise levels at 
Long Wharf may vary with noise levels being higher at Berth 1, likely 
due to its closer proximity to the main shipping channel.
BILLING CODE 3510-22-P

[[Page 19250]]

[GRAPHIC] [TIFF OMITTED] TN31MR23.025

BILLING CODE 3510-22-C

Figure 1--Chevron Long Wharf Project Area

Detailed Description of the Specified Activity

    The LWMEP upgrades began in 2018 and were planned to be completed 
within 2-3 years, however, the project experienced several delays. The 
proposed IHA would cover activities that were not completed under the 
2021 IHA (86 FR 28578, May 27, 2021).
    Chevron plans to complete modifications to Berth 1 at the Long 
Wharf by updating the fender system to better accommodate barges and 
enable balanced utilization across berths. Specifically, these 
modifications include replacing the gangway, construction of a new 
mooring dolphin and hook and breasting dolphin with breasting point, 
removing a catwalk and concrete piles, and installing a temporary 
construction template. Unless otherwise specified, the term ``pile 
driving'' in this section, and all following sections, may refer to 
either pile installation or removal.
    Gangway Replacement--The existing gangway would be replaced in 
order to accommodate barges. Four 24-inch concrete piles would be 
installed using an impact hammer at a rate of 2 piles per day (table 
1). A new raised fire monitor would be added as well. However, addition 
of the fire monitor would occur above water, and therefore, we do not 
anticipate take of marine mammals associated with this activity, and it 
is not discussed further.
    Mooring Dolphin and Hook Construction--A new 24 feet (ft) (7.3 
meters (m)) by 25 ft (7.6 m) mooring dolphin and hook would be 
installed to accommodate barges at Berth 1. An impact hammer would be 
used to drive 13 24-inch concrete piles at a rate of 2 piles per day 
(table 1).
    Breasting Dolphin and Breasting Point Construction--A new 24 ft 
(7.3 m) by 25 ft (7.6 m) breasting dolphin would be installed with a 13 
ft (4 m) by 26 ft (7.9 m) breasting point with standoff fenders to 
accommodate barges. The breasting dolphin would be constructed using an 
impact hammer to install 17 24-inch concrete piles at a rate of 2 piles 
per day (table 1). The breasting point with standoff fenders would be 
installed using an impact hammer to drive 8 24-inch concrete piles at a 
rate of 2 piles per day. Construction of the breasting dolphin and 
breasting point also require the removal of an existing catwalk and 2 
18-inch concrete piles. These piles

[[Page 19251]]

would be removed through the use of vibratory extraction over 1 day. 
The existing catwalk would be replaced by a new catwalk in a different 
location. Removal and replacement of the catwalk would occur above 
water, and therefore, we do not anticipate take of marine mammals 
associated with this activity, and it is not discussed further.
    In addition to the planned modifications, Chevron would construct a 
temporary template using 12 36-inch steel piles. These piles would be 
installed using vibratory installation and removed using vibratory 
extraction after in-water construction activities are complete.
    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. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, incorporated here by reference, instead of 
reprinting the information. Additional information regarding population 
trends and threats may be found in NMFS' Stock Assessment Reports 
(SARs; www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these 
species (e.g., physical and behavioral descriptions) may be found on 
NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this activity, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. 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' 
SARs). While no serious injury or mortality is anticipated or proposed 
to be authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species or stocks 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' 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' U.S. Pacific SARs. All values presented in table 2 are the most 
recent available at the time of publication (including from the draft 
2022 SARs) and are available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                  Table 2--Marine Mammal Species \4\ Likely To Be Impacted by the Specified Activities
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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 Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
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Family Eschrichtiidae:
    Gray whale......................  Eschrichtius robustus..  Eastern North Pacific..  -, -, N             26,960 (0.05, 25,849,         801        131
                                                                                                             2016).
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                                                  Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
    Bottlenose dolphin..............  Tursiops truncatus.....  California Coastal.....  -, -, N             453 (0.06, 346, 2011).        2.7      >=2.0
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  San Francisco/Russian    -, -, N             7,777 (0.62, 4,811,            73      >=0.4
                                                                River.                                       2017).
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                                                               Order Carnivora--Pinnipedia
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Family Otariidae (eared seals and
 sea lions):
    California sea lion.............  Zalophus californianus.  U.S....................  -, -, N             257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Northern fur seal \5\...........  Callorhinus ursinus....  California.............  -, D, N             14,050 (N/A, 7,524,           451        1.8
                                                                                                             2013).
Family Phocidae (earless seals):
    Harbor seals....................  Phoca vitulina.........  California.............  -, -, N             30,968 (N/A, 27,348,        1,641         43
                                                                                                             2012).
    Northern elephant seal..........  Mirounga angustirostris  California Breeding....  -, -, N             187,386 (N/A, 85,369,       5,122       13.7
                                                                                                             2013).
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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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments/ assessments/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable as in the case of
  the pinnipeds, as population estimates are dependent upon the numbers of individuals hauled out or the number of pups.
\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.
\4\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)).
\5\ Survey years = Sea Lion Rock--2014; St. Paul and St. George Is--2014, 2016, 2018; Bogoslof Is.--2015, 2019.


[[Page 19252]]

    As indicated above, all 7 species (with 7 number managed stocks) in 
table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. All species that could 
potentially occur in the proposed survey areas are included in table 4-
1 of the IHA application. While humpback whales have been sighted in 
the coastal waters outside of the Bay, the spatial occurrence of this 
species is such that take is not expected to occur, and they are not 
discussed further beyond the explanation provided here. Although there 
are no published studies available regarding the distribution of 
humpback whales in the Bay, sightings from whale watching vessels and 
other mariners report that when humpback whales enter the Bay, they 
rarely move east into the Bay towards the vicinity of the project area 
and are unlikely to occur during the proposed activities.

Harbor Seal

    Pacific harbor seals are distributed from Baja California north to 
the Aleutian Islands of Alaska. Harbor seals do not make extensive 
pelagic migrations, but may travel hundreds of kilometers to find food 
or suitable breeding areas (Herder, 1986; Harvey and Goley, 2011; 
Carretta et al., 2022).
    The California Department of Transportation (Caltrans) conducted 
extensive marine mammal surveys in Bay before and during seismic 
retrofit on the RSRB from 1998-2002 and determined that a minimum of 
500 harbor seals occur within the Bay (Green et al., 2002). This 
estimate aligns with more recent seal counts (Lowry et al., 2008; Codde 
et al., 2020). The California harbor seal stock may be stabilizing at 
or near carrying capacity, although conservation concerns such as 
vessel strikes, disturbance, fishing gear entanglement, and habitat 
loss are still a concern in the Bay area (Duncan, 2019).
    The number of harbor seals in the Bay increases during the winter 
foraging period as compared to the spring breeding season. In the Bay, 
harbor seals are known to forage on a variety of fish, crustaceans, and 
cephalopods found in shallow intertidal waters.
    Seals primarily haul out on remote mainland and island beaches, 
reefs, and estuary areas. At haul-outs, they congregate to rest, 
socialize, breed, and molt. Haul out sites are consistent for harbor 
seals across years (Kopec and Harvey, 1995), and females may return to 
their natal sites for breeding (Green et al., 2006). The nearest major 
haul out site to the project area is Castro Rocks, located 
approximately 1,400 meters (0.87 miles) north of the Berth 1 of Long 
Wharf. Use of Castro Rocks as a haul out site has been increasing over 
the years (Codde et al., 2020). Seals haul out on Castro Rocks year-
round during medium to low tides, and usage of this haul out site is 
highest during the summer molting period of June-July. During the LWMEP 
2020-2021 construction period, protected species observers (PSOs) 
observed the number of harbor seals on Castro Rocks to vary greatly, 
from 0 to 90 individuals, depending upon the tide level (AECOM, 2021). 
Due to the proximity of Long Wharf to the Castro Rocks haul out site 
and previous monitoring conducted by Chevron, it is likely that harbor 
seals would be in the project area during construction activities.

California Sea Lion

    California sea lions are mainly seen swimming off the San Francisco 
and Marin shorelines within the Bay, but may occasionally enter the 
project area to forage. They feed seasonally on schooling fish and 
cephalopods, including salmon, herring, sardines, anchovy, mackerel, 
whiting, rockfish, and squid (Lowry et al., 1990, 1991; Weise 2000; 
Carretta et al., 2022; Lowry et al., 2022). In central California sea 
lion populations, short term seasonal variations in diet are related to 
prey movement and life history patterns while long-term annual changes 
correlate to large-scale ocean climate shifts and foraging competition 
with commercial fisheries (Weise and Harvey, 2008; McClatchie et al., 
2016). Conservation concerns for California sea lions include prey 
species availability due to climate change, vessel strikes, non-
commercial fishery human caused mortality, hookworms, and competition 
for forage with commercial fisheries (Carretta et al., 2018; Carretta 
et al., 2022).
    Although California sea lions forage and conduct many activities 
within the water, they also use haul outs on land. In the Bay, sea 
lions haul out primarily on floating docks at Pier 39 at the 
Fisherman's Wharf area of the San Francisco Marina, approximately 12.5 
kilometers (7.8 miles) southwest of the project area. Haul out numbers 
at Pier 39 vary seasonally. In addition to the Pier 39 haul out, 
California sea lions haul out on buoys, wharfs, and similar structures 
throughout the Bay.
    Occurrence of sea lions in the Bay is typically lowest in June 
during the breeding season and higher during El Ni[ntilde]o seasons. In 
the Bay, California sea lions have been observed foraging near Pier 39, 
in the shipping channel south of Yerba Buena Island, and along the west 
and north sides of the Long Wharf (AECOM, 2019). The relatively deep 
shipping channel west and north of the Point Orient Wharf also provides 
foraging area for sea lions. PSOs observed up to 13 sea lions within a 
construction season during prior monitoring efforts for the LWMEP 
(AECOM, 2021). As sea lions may forage widely throughout the Bay, this 
species may enter the project area during construction activities.

Harbor Porpoise

    Harbor porpoises typically occur in cool temperate to sub-polar 
waters less than 62.6 degrees Fahrenheit (17 degrees Celsius) (Read 
1999) where prey aggregations are concentrated (Watts and Gaskin, 
1985). In the eastern Pacific, harbor porpoises occur in coastal and 
inland waters from Point Conception, California to Alaska (Gaskin 
1984). The non-migratory San Francisco-Russian River stock ranges from 
Pescadero to Point Arena, California, utilizes relatively shallow 
nearshore waters (<100 meters), and feeds on small schooling fishes 
such as northern anchovy and Pacific herring which enter the Bay 
(Caretta et al., 2022; Stern et al., 2017). Harbor porpoises tend to 
occur in small groups and are considered to be relatively cryptic 
animals.
    Before 2008, harbor porpoises occurred primarily outside of the Bay 
although the Bay has historically been considered habitat for harbor 
porpoises (Broughton, 1999). Recently, observations of harbor porpoises 
within the Bay have become more common (Duffy 2015; Stern et al., 2017; 
AECOM, 2021). From 2011-2014, the Golden Gate Cetacean Research (GGCR) 
program conducted a visual count and identified 2,698 porpoise groups 
from the Golden Gate Bridge during 96 percent of their on-effort survey 
days (Stern et al., 2017). During 2021 LWMEP monitoring, PSOs observed 
harbor porpoises swimming past the Bay side of the Long Wharf on four 
different occasions (AECOM, 2021). Harbor porpoise movements into the 
Bay are linked to tidal cycle with the greatest numbers of porpoises 
sighted during high tide to ebb tide periods. Movements into the Bay 
are likely influenced by prey availability (Duffy 2015; Stern et al., 
2017) and may serve as a foraging area. Although harbor porpoise 
sightings are generally concentrated in the vicinity of the Golden Gate 
Bridge and Angel Island, southwest of the project site (Keener, 2011), 
this species is occurring more frequently in the Bay east of Angel 
Island and may approach the project area during pile driving 
activities.

[[Page 19253]]

Bottlenose Dolphin

    The common bottlenose dolphin is found in all oceans across the 
globe, and is one of the most commonly observed marine mammal species 
in coastal waters and estuaries. Two genetically distinct stocks occur 
off the coast of California, the California coastal stock and the 
California/Oregon/Washington offshore stock. The range of the 
California coastal stock has been expanding north since an El 
Ni[ntilde]o event in 1982-1983 (Hansen and Defran, 1990; Wells et al., 
1990) and spans as far north as Sonoma County (Keener et al., 2023). 
From 2010-2018, a photo-identification monitoring study identified 84 
distinctive individual bottlenose dolphins in the Bay, likely belonging 
to the California coastal stock (Keener et al., 2023). This stock shows 
little site fidelity and individuals are highly mobile (Weller et al., 
2016). Since 2008, coastal bottlenose dolphins have been observed 
regularly in the Bay, mainly in proximity to the Golden Gate near the 
mouth of the Bay (Bay Nature, 2020). PSOs did not observe bottlenose 
dolphins during prior monitoring efforts for the LWMEP. However, due to 
increased numbers of dolphins occurring in the Bay, it is possible that 
a limited number of individuals may approach the project area during 
in-water construction activities.

Gray Whale

    Gray whales are one of the most common whales along the California 
coast. A small number of whales, known as the Pacific Coast Feeding 
Group (PCFG), are known to feed along the Pacific coast between Kokiak 
Island, AK and northern California, as well as in nearshore waters just 
outside of the Bay (Carretta et al., 2022). The southward migration to 
winter breeding grounds occurs from December through February while the 
northward migration to the feeding grounds takes place from February 
through May, peaking in March (NOAA NCOSS, 2007). A few individuals may 
enter the Bay during the northward migration. Since 2019, it has become 
more common for gray whales on their northward migration to enter the 
Bay during the months of February and March to feed (Bartlett, 2022), 
although many only travel up to 2 miles into the Bay (Self, 2012). 
Although it is more likely that a gray whale would enter the Bay from 
February to March, it is possible a gray whale may enter the project 
area during pile driving activities.
    Eastern North Pacific gray whales have been experiencing a UME 
since 2019 when large numbers of whales began stranding from Mexico to 
Alaska. As of March 14, 2023, approximately 307 gray whales have 
stranded in the U.S. and 633 total throughout the U.S., Canada, and 
Mexico since 2019 (NOAA, 2023). Preliminary necropsy results conducted 
on a subset of the whales indicated that many whales showed signs of 
nutritional stress, however, these findings are not consistent across 
all of the whales examined (NOAA, 2023). This UME is ongoing and 
similar to that of 1999 and 2000 when large numbers of gray whales 
stranded along the eastern Pacific coast (Moore et al., 2001; Gulland 
et al., 2005). Oceanographic factors limiting food availability for 
whales was identified as a likely cause of the prior UME and may also 
be influencing the current UME (LeBouef et al., 2000; Moore et al., 
2001; Minobe 2002; Gulland et al., 2005).

Northern Elephant Seal

    Northern elephant seals breed and give birth in California and Baja 
California, mainly on offshore islands during the months of December to 
March (Stewart and Huber, 1993; Stewart et al., 1994; Carretta et al., 
2022). Molting season takes place from March to August. Adults 
typically reside in offshore pelagic waters when not breeding or 
molting, however, a healthy juvenile male was observed basking at 
Aquatic Park in San Francisco in the spring of 2019 (Hern[aacute]ndez, 
2020). PSOs did not observe northern elephant seals during prior 
monitoring efforts for the LWMEP. Although rare visitors to the Bay, it 
is possible that a few individuals may be present during construction 
activities.

Northern Fur Seal

    Northern fur seals range from southern California north to the 
Bering Sea, and west to the Okhotsk Sea and Honshu Island, Japan in the 
west (Carretta et al., 2022). The majority of the population breeds on 
the Pribilof Islands in the southern Bering Sea, although a small 
percentage of the population breed at San Miguel Island and the 
Farallon Islands off the coast of California. Northern fur seals show 
high site fidelity to breeding and rookery locations, and may swim long 
distances for prey. Their diet is composed of small schooling fish such 
as walleye Pollock, herring, hake, anchovy, and squid. Diet and 
population trends vary with environmental conditions, such as El 
Ni[ntilde]o (Carretta et al., 2022). The California stock of northern 
fur seals forage in waters outside of the Bay. Juvenile northern fur 
seals occasionally strand in the Bay, especially during El Ni[ntilde]o 
events (TMMC 2016). The Marine Mammal Center (TMMC) responds to 
approximately five northern fur seal strandings per year in the Bay 
(TMMC, 2016). PSOs did not observe northern fur seals during prior 
monitoring efforts for the LWMEP. Although rarely observed in the Bay, 
it is possible individuals may be present during construction 
activities.

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. 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, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (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. Marine mammal hearing 
groups and their associated hearing ranges are provided in table 3.

[[Page 19254]]



                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
                                                    Generalized hearing
                  Hearing group                           range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales)....  7 Hz to 35 kHz.
Mid-frequency (MF) cetaceans (dolphins, toothed   150 Hz to 160 kHz.
 whales, beaked whales, bottlenose whales).
High-frequency (HF) cetaceans (true porpoises,    275 Hz to 160 kHz.
 Kogia, river dolphins, Cephalorhynchid,
 Lagenorhynchus cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true seals).  50 Hz to 86 kHz.
Otariid pinnipeds (OW) (underwater) (sea lions    60 Hz to 39 kHz.
 and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    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 (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take 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 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 whether those 
impacts are reasonably expected to, or reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.
    Acoustic effects on marine mammals during the specified activities 
can occur from impact pile driving and vibratory pile driving and 
removal. The effects of underwater noise from Chevron's proposed 
activities have the potential to result in Level B harassment of marine 
mammals in the project area.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far (ANSI, 1995). The sound level of an area is 
defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., waves, wind, 
precipitation, earthquakes, ice, atmospheric sound), biological (e.g., 
sounds produced by marine mammals, fish, and invertebrates), and 
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
    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 
decibels (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 activities 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 and vibratory pile driving and removal. The sounds 
produced by these activities fall into one of two general sound types: 
impulsive and non-impulsive. Impulsive sounds (e.g., explosions, sonic 
booms, impact pile driving) are typically transient, brief (less than 1 
second), broadband, and consist of high peak sound pressure with rapid 
rise time and rapid decay (ANSI, 1986; NIOSH, 1998; NMFS, 2018). Non-
impulsive sounds (e.g., machinery operations such as drilling or 
dredging, vibratory pile driving, underwater chainsaws, and active 
sonar systems) can be broadband, narrowband or tonal, brief or 
prolonged (continuous or intermittent), and typically do not have the 
high peak sound pressure with raid rise/decay time that impulsive 
sounds do (ANSI, 1995; NIOSH, 1998; NMFS, 2018). 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).
    Two types of hammers would be used on this project, impact and 
vibratory. Impact hammers operate by repeatedly dropping and/or pushing 
a heavy piston onto a pile to drive the pile into the substrate. Sound 
generated by impact hammers is considered impulsive. Vibratory hammers 
install piles by vibrating them and allowing the weight of the hammer 
to push them into the sediment. Vibratory hammers produce non-
impulsive, continuous sounds. Vibratory hammering generally produces 
SPLs 10 to 20 dB lower than 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; Carlson et al., 2005).
    The likely or possible impacts of Chevron's proposed activities on 
marine mammals could be generated from both non-acoustic and acoustic 
stressors. Potential non-acoustic stressors include the physical 
presence of the equipment, vessels, and personnel; however, we expect 
that any animals that approach the project site close enough to be 
harassed due to the presence of equipment or personnel would be within 
the Level B harassment zones from pile driving and would already be 
subject to harassment from the in-water activities. Therefore, any 
impacts to marine mammals are expected to primarily be acoustic in 
nature.

[[Page 19255]]

Acoustic stressors are generated by heavy equipment operation during 
pile driving activities (i.e., impact and vibratory pile driving and 
removal).

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving equipment is the primary means by which 
marine mammals may be harassed from Chevron's specified activities. In 
general, animals exposed to natural or anthropogenic sound may 
experience physical and psychological effects, ranging in magnitude 
from none to severe (Southall et al., 2007). Generally, exposure to 
pile driving and removal and other construction noise has the potential 
to result in auditory threshold shifts and behavioral reactions (e.g., 
avoidance, temporary cessation of foraging and vocalizing, changes in 
dive behavior). Exposure to anthropogenic noise can also lead to non-
observable physiological responses, such as an increase in stress 
hormones. Additional noise in a marine mammal's habitat can mask 
acoustic cues used by marine mammals to carry out daily functions, such 
as communication and predator and prey detection. The effects of pile 
driving and demolition noise on marine mammals are dependent on several 
factors, including, but not limited to, sound type (e.g., impulsive vs. 
non-impulsive), the species, age and sex class (e.g., adult male vs. 
mother with calf), duration of exposure, the distance between the pile 
and the animal, received levels, behavior at time of exposure, and 
previous history with exposure (Wartzok et al., 2004; Southall et al., 
2007). Here we discuss physical auditory effects (threshold shifts) 
followed by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014a), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Available data 
from humans and other terrestrial mammals indicate that a 40 dB 
threshold shift approximates PTS onset (see Ward et al., 1958, 1959; 
Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; 
Henderson et al., 2008). PTS levels for marine mammals are estimates, 
because there are limited empirical data measuring PTS in marine 
mammals (e.g., Kastak et al., 2008), largely due to the fact that, for 
various ethical reasons, experiments involving anthropogenic noise 
exposure at levels inducing PTS are not typically pursued or authorized 
(NMFS, 2018).
    Temporary Threshold Shift (TTS)--TTS is a temporary, reversible 
increase in the threshold of audibility at a specified frequency or 
portion of an individual's hearing range above a previously established 
reference level (NMFS, 2018). Based on data from cetacean TTS 
measurements (see Southall et al., 2007), a TTS of 6 dB is considered 
the minimum threshold shift clearly larger than any day-to-day or 
session-to-session variation in a subject's normal hearing ability 
(Schlundt et al., 2000; Finneran et al., 2000, 2002). As described in 
Finneran (2016), marine mammal studies have shown the amount of TTS 
increases with cumulative sound exposure level (SELcum) in 
an accelerating fashion: At low exposures with lower SELcum, 
the amount of TTS is typically small and the growth curves have shallow 
slopes. At exposures with higher SELcum, the growth curves 
become steeper and approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
masking, below). For example, a marine mammal may be able to readily 
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal 
is traveling through the open ocean, 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. We note that reduced hearing sensitivity as 
a simple function of aging has been observed in marine mammals, as well 
as humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    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 five species of pinnipeds exposed to a limited number of sound 
sources (i.e., mostly tones and octave-band noise) in laboratory 
settings (Finneran, 2015). TTS was not observed in trained spotted 
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive 
noise at levels matching previous predictions of TTS onset (Reichmuth 
et al., 2016). In general, harbor seals and harbor porpoises have a 
lower TTS onset than other measured pinniped or cetacean species 
(Finneran, 2015). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al., 2019a, 2019b, 2020a, 2020b). In addition, TTS 
can accumulate across multiple exposures, but the resulting TTS will be 
less than the TTS from a single, continuous exposure with the same SEL 
(Finneran et al., 2010; Kastelein et al., 2014b; Kastelein et al., 
2015a; Mooney et al., 2009). This means that TTS predictions based on 
the total, cumulative SEL will overestimate the amount of TTS from 
intermittent exposures such as sonars and impulsive sources.
    The potential for TTS from impact pile driving exists. After 
exposure to playbacks of impact pile driving sounds (rate 2,760 
strikes/hour) in captivity, mean TTS increased from 0 dB after 15 
minute exposure to 5 dB after 360 minute exposure; recovery occurred 
within 60 minutes (Kastelein et al., 2016). Additionally, the existing 
marine mammal TTS data come from a limited number of individuals within 
these species. No data are available on noise-induced hearing loss for 
mysticetes. Nonetheless, what we considered is the best available 
science. For summaries of data on TTS in marine mammals or for

[[Page 19256]]

further discussion of TTS onset thresholds, please see Southall et al. 
(2007, 2019), Finneran and Jenkins (2012), Finneran (2015), and table 5 
in NMFS (2018).
    Activities for this project include impact and vibratory pile 
driving, and vibratory pile removal. There would likely be pauses in 
activities producing the sound during each day. Given these pauses and 
the fact that many marine mammals are likely moving through the project 
areas and not remaining for extended periods of time, the potential for 
TS declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal also has the potential to behaviorally disturb marine mammals. 
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 Bejder, 2007; Weilgart, 2007; NRC, 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); or avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul-out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006). 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., 2004; Southall et al., 
2007; Weilgart, 2007; Archer et al., 2010; Southall et al., 2021). 
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). In general, pinnipeds seem more tolerant of, or at 
least habituate more quickly to, potentially disturbing underwater 
sound than do cetaceans, and generally seem to be less responsive to 
exposure to industrial sound than most cetaceans. Please see Appendices 
B and C of Southall et al. (2007) as well as Nowacek et al. (2007); 
Ellison et al. (2012), and Gomez et al. (2016) for a review of studies 
involving marine mammal behavioral responses to sound.
    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; 
Melc[oacute]n et al., 2012). In addition, behavioral state of the 
animal plays a role in the type and severity of a behavioral response, 
such as disruption to foraging (e.g., Sivle et al., 2016; Wensveen et 
al., 2017). 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 (Goldbogen et al., 2013).
    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 
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 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), however 
distress is an unlikely result of these projects based on observations 
of marine mammals during previous, similar projects in the area.
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of

[[Page 19257]]

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., pile driving, 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. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked. 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., 2007; Di Iorio and Clark, 2009; Holt 
et al., 2009). The Bay is heavily used by commercial, recreational, and 
military vessels, and background sound levels in the area are already 
elevated. Due to the transient nature of marine mammals to move and 
avoid disturbance, masking is not likely to have long-term impacts on 
marine mammal species within the proposed project area.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal 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 would 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 their heads above 
water. Most likely, airborne sound would cause behavioral responses 
similar to those discussed above in relation to underwater sound. For 
instance, anthropogenic sound could cause hauled-out pinnipeds to 
exhibit changes in their normal behavior, such as reduction in 
vocalizations, or cause them to temporarily abandon the area and move 
further from the source. However, these animals would likely previously 
have been ``taken'' because of exposure to underwater sound above the 
behavioral harassment thresholds, which are generally larger than those 
associated with airborne sound. Thus, the behavioral harassment of 
these animals is already accounted for in these estimates of potential 
take. Therefore, we do not believe that authorization of incidental 
take resulting from airborne sound for pinnipeds is warranted, and 
airborne sound is not discussed further here.

Marine Mammal Habitat Effects

    Chevron's proposed construction activities could have localized, 
temporary impacts on marine mammal habitat, including prey, by 
increasing in-water sound pressure levels and slightly decreasing water 
quality. Increased noise levels may affect acoustic habitat (see 
masking discussion above) and adversely affect marine mammal prey in 
the vicinity of the project areas (see discussion below). During impact 
and vibratory pile driving or removal, elevated levels of underwater 
noise would ensonify the project area where both fishes and mammals 
occur, and could affect foraging success. Additionally, marine mammals 
may avoid the area during construction, however, displacement due to 
noise is expected to be temporary and is not expected to result in 
long-term effects to the individuals or populations. Construction 
activities are expected to be of short duration and would likely have 
temporary impacts on marine mammal habitat through increases in 
underwater and airborne sound.
    A temporary and localized increase in turbidity near the seafloor 
would occur in the immediate area surrounding the area where piles are 
installed or removed. In general, turbidity associated with pile 
driving is localized to about a 25-ft (7.6-m) radius around the pile 
(Everitt et al., 1980). Cetaceans are not expected to be close enough 
to the pile driving areas to experience effects of turbidity, and any 
pinnipeds could avoid localized areas of turbidity. Local currents are 
anticipated to disburse any additional suspended sediments produced by 
project activities at moderate to rapid rates depending on tidal stage. 
Therefore, we expect the impact from increased turbidity levels to be 
discountable to marine mammals and do not discuss it further.
    In-Water Construction Effects on Potential Foraging Habitat--The 
area likely impacted by the LWMEP is relatively small compared to the 
total available habitat in the Bay. The proposed project area is highly 
influenced by anthropogenic activities and provides limited foraging 
habitat for marine mammals. Furthermore, pile driving and removal at 
the proposed project site would not obstruct long-term movements or 
migration of marine mammals.
    Avoidance by potential prey (i.e., fish) of the immediate area due 
to the temporary loss of this foraging habitat is also possible. The 
duration of fish and marine mammal avoidance of this area after pile 
driving stops is unknown, but a rapid return to normal recruitment, 
distribution, and behavior is anticipated. Any behavioral avoidance by 
prey of the disturbed area would still leave significantly large areas 
of potential foraging habitat in the nearby vicinity.
    In-water Construction Effects on Potential Prey--Sound may affect 
marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton, other marine mammals). Marine mammal prey varies by 
species, season, and location. Here, we describe studies regarding the 
effects of noise on known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). Depending on their hearing anatomy and peripheral sensory 
structures, which vary among species, fishes hear sounds using pressure 
and particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage,

[[Page 19258]]

barotrauma (pressure-related injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
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; several are based on 
studies in support of large, multiyear bridge construction projects 
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Many 
studies have demonstrated that impulse sounds might affect the 
distribution and behavior of some fishes, potentially impacting 
foraging opportunities or increasing energetic costs (e.g., Fewtrell 
and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992; 
Santulli et al., 1999; Paxton et al., 2017). In response to pile 
driving, Pacific sardines and northern anchovies may exhibit an 
immediate startle response to individual strikes, but return to 
``normal'' pre[hyphen]strike behavior following the conclusion of pile 
driving with no evidence of injury as a result (appendix C in NAVFAC 
SW, 2014). However, some studies have shown no or slight reaction to 
impulse sounds (e.g., Pena et al., 2013; Wardle et al., 2001; Jorgenson 
and Gyselman, 2009; Popper et al., 2005).
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours 
for one species. Impacts would be most severe when the individual fish 
is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    The most likely impact to fishes from pile driving and removal and 
construction activities at the project area would be temporary 
behavioral avoidance of the 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 are expected to be minor 
and temporary. Further, it is anticipated that preparation activities 
for pile driving or removal (i.e., positioning of the hammer, clipper 
or wire saw) and upon initial startup of devices would cause fish to 
move away from the affected area outside areas where injuries may 
occur. Therefore, relatively small portions of the proposed project 
area would be affected for short periods of time, and the potential for 
effects on fish to occur would be temporary and limited to the duration 
of sound[hyphen]generating activities.
    In summary, given the short daily duration of sound associated with 
individual pile driving events and the relatively small areas being 
affected, pile driving activities associated with the proposed actions 
are not likely to have a permanent, adverse effect on any fish habitat, 
or populations of fish species. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large potential areas 
fish and marine mammal foraging habitat in the nearby vicinity. Thus, 
we conclude that impacts of the specified activities are not likely to 
have more than short-term adverse effects on any prey habitat or 
populations of prey species. Further, any impacts to marine mammal 
habitat are not expected to result in significant or long-term 
consequences for individual marine mammals, or to contribute to adverse 
impacts on their populations.

Estimated Take of Marine Mammals

    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 
determinations.
    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 be by Level B harassment only, in the form 
of disruption of behavioral patterns for individual marine mammals 
resulting from exposure to the acoustic sources. Based on the nature of 
the activity and the anticipated effectiveness of the mitigation 
measures (i.e., shutdown zones, PSO monitoring) discussed in detail 
below in the Proposed Mitigation section, Level A harassment is neither 
anticipated nor proposed to be authorized.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the proposed take numbers are estimated.
    For acoustic impacts, generally speaking, 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) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the proposed take estimates.

Acoustic Thresholds

    NMFS recommends the use of 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--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 or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and

[[Page 19259]]

measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by TTS as, in most cases, the likelihood of 
TTS occurs at distances from the source less than those at which 
behavioral harassment is likely. TTS of a sufficient degree can 
manifest as behavioral harassment, as reduced hearing sensitivity and 
the potential reduced opportunities to detect important signals 
(conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur.
    Chevron's proposed construction activities include the use of 
continuous (vibratory pile-driving) and impulsive (impact pile-driving) 
sources, and therefore the RMS SPL thresholds of 120 and 160 dB re 1 
[mu]Pa are applicable.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) 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). Chevron's 
proposed construction activities include the use of impulsive (impact 
hammer) and non-impulsive (vibratory hammer) sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                        PTS onset thresholds * (received level)
            Hearing group             --------------------------------------------------------------------------
                                              Impulsive                           Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans.........  Cell 1: Lp,0-pk,flat:    Cell 2: LE,p, LF,24h: 199 dB.
                                        219 dB; LE,p,LF,24h:
                                        183 dB.
Mid-Frequency (MF) Cetaceans.........  Cell 3: Lp,0-pk,flat:    Cell 4: LE,p,MF,24h: 198 dB.
                                        230 dB; LE,p,MF,24h:
                                        185 dB.
High-Frequency (HF) Cetaceans........  Cell 5: Lp,0-pk,flat:    Cell 6: LE,p,HF,24h: 173 dB.
                                        202 dB; LE,p,HF,24h:
                                        155 dB.
Phocid Pinnipeds (PW) (Underwater)...  Cell 7: Lp,0-pk.flat:    Cell 8: LE,p,PW,24h: 201 dB.
                                        218 dB; LE,p,PW,24h:
                                        185 dB.
Otariid Pinnipeds (OW) (Underwater)..  Cell 9: Lp,0-pk,flat:    Cell 10: LE,p,OW,24h: 219 dB.
                                        232 dB; LE,p,OW,24h:
                                        203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 are recommended for consideration.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
  exposure level (LE,p) has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
  is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
  hearing range of marine mammals (i.e., 7 Hz to 160 kHz). 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 weighted
  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 thresholds will be exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    Pile driving activities, using an impact hammer as well as a 
vibratory hammer, would generate underwater noise that could result in 
disturbance to marine mammals near the project area. A review of 
underwater sound measurements for similar projects was conducted to 
estimate the near-source sound levels for impact and vibratory pile 
driving and vibratory extraction. Source levels for proposed removal 
and installation activities derived from this review are shown in table 
5.

                                      Table 5--Source Levels for Proposed Pile Removal and Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               Source levels (dB)/source distance (m)
                                                                       -----------------------------------------------------
                  Method                            Pile type             Peak sound     Mean maximum                                 Reference
                                                                         pressure (dB   RMS SPL (dB re      SEL (dB re 1
                                                                         re 1 [mu]Pa)      1 [mu]Pa)        [mu]Pa2 sec)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact install \1\.......................  24-inch square concrete              191/10          173/10               161/10  AECOM (2018, 2019).
                                            pile.
Vibratory install/extract................  36-inch steel shell pile...          196/10          167/15                  167  AECOM (2019).
Vibratory extract \2\....................  18-inch concrete pile......             N/A          163/10                  150  NAVFAC SW (2022).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Chevron would use a bubble curtain attenuation system for all impact pile driving. NMFS conservatively assumes that the bubble curtain would result
  in a 5 dB reduction in sound. These source levels incorporate the 5 dB reduction.
\2\ 20-inch concrete piles used as a proxy as vibratory data for 18-inch concrete piles was not available.


[[Page 19260]]

    Level B Harassment Zones--Transmission loss (TL) is the decrease in 
acoustic intensity as an acoustic pressure wave propagates out from a 
source. TL parameters vary with frequency, temperature, sea conditions, 
current, source and receiver depth, water depth, water chemistry, and 
bottom composition topography. The general formula for underwater TL 
is:

TL = B * Log10 (R1/R2),

where
TL = transmission loss in dB;
B = transmission loss coefficient;
R1 = the distance of the modeled SPL from the driven 
pile; and
R2 = the distance from the driven pile of the initial 
measurement.

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, known as practical spreading. As 
is common practice in coastal waters, here we assume practical 
spreading (4.5 dB reduction in sound level for each doubling of 
distance) for vibratory extraction of concrete piles, as hydro-acoustic 
data for the same pile type was not available for this project site. 
Chevron conducted hydro-acoustic monitoring for prior projects at Long 
Wharf for the impact driving of 24-inch concrete piles and vibratory 
driving of 36-inch steel piles. Based upon hydro-acoustic monitoring 
conducted at Long Wharf in 2018 and 2019 (AECOM 2018, 2019), Chevron 
calculated a transmission loss coefficient ranging from 14 to 20 (~4.4 
dB to 8 dB per doubling of distance). As this estimate represents a 
wide range of measured transmission loss, NMFS applied the standard 
value of 15 for impact driving of concrete piles. For vibratory driving 
of 36-inch steel piles, Chevron calculated a transmission loss 
coefficient of 20.8 to 25.0 (~8 dB to 9 dB per doubling of distance) 
from hydro-acoustic monitoring conducted at Long Wharf in 2019 (AECOM, 
2019). Given that all available data suggested a higher transmission 
loss, NMFS found it appropriate to apply this to its analysis. NMFS 
applied the lower of these two values, 20.8 TL, to this analysis to be 
conservative. The Level B harassment zones and ensonified areas for 
Chevron's proposed activities are shown in table 6.

                     Table 6--Distance to Level B Harassment Thresholds and Ensonified Areas
----------------------------------------------------------------------------------------------------------------
                                                    Source levels (dB)/ source      Distance to
                                                           distance (m)               Level B       Ensonified
                    Pile type                    --------------------------------   harassment     area (km\2\)
                                                       Peak             RMS       thresholds (m)
----------------------------------------------------------------------------------------------------------------
Impact Installation:
    24-inch square concrete pile................          191/10          173/10              74            0.02
Vibratory Installation:
    36-inch steel shell pile....................          196/10          167/15           2,727           23.36
Vibratory Extraction:
    18-inch concrete pile.......................             N/A          163/10           7,356             170
    36-inch steel shell pile....................          196/10          167/15           2,727           17.24
----------------------------------------------------------------------------------------------------------------

    Level A Harassment Thresholds--The ensonified area associated with 
Level A harassment is more technically challenging to predict due to 
the need to account for a duration component. Therefore, NMFS developed 
an optional User Spreadsheet tool to accompany the Technical Guidance 
that can be used to relatively simply predict an isopleth distance for 
use in conjunction with marine mammal density or occurrence to help 
predict potential takes. We note that because of some of the 
assumptions included in the methods underlying the optional tool, we 
anticipate that the resulting isopleth estimates are typically going to 
be overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources, such as pile driving activities, the optional User 
Spreadsheet tool predicts the closest distance at which a stationary 
animal would not be expected to incur PTS if the sound source traveled 
by the stationary animal in a straight line at a constant speed. The 
isopleths generated by the User Spreadsheet used the same TL 
coefficients as the Level B harassment zone calculations, as indicated 
above for each activity type. Inputs used in the User Spreadsheet 
(e.g., number of piles per day, duration and/or strikes per pile) are 
presented in table 1. The maximum RMS SPL/SEL SPL as well as peak SPL 
and resulting isopleths are reported below in table 7. The RMS SPL 
value was used to calculate Level A harassment isopleths for vibratory 
pile driving and extraction activities, while the single strike SEL SPL 
value was used to calculate Level A isopleths for impact pile driving 
activity.

                                 Table 7--Distance to Level A Harassment Thresholds for Each Marine Mammal Hearing Group
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Source levels (dB)/ source distance (m)             Distances to Level A harassment threshold (m)
                                          --------------------------------------------------------------------------------------------------------------
                Pile type                                                                     Lf           Mf           Hf         Phocid      Otariid
                                               Peak                 RMS/SEL               cetaceans    cetaceans    cetaceans    pinnipeds    pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation:
    24-inch square concrete pile.........       191/10  161/10 SEL.....................         31.3          1.1         37.3         16.8          1.2
Vibratory Installation:
    36-inch steel shell pile.............       196/10  167/15 RMS.....................         15.9          2.8           21         11.1          1.6
Vibratory Extraction:
    18-inch concrete pile................          N/A  163/10 RMS.....................          3.4          0.3            5          2.1          0.1

[[Page 19261]]

 
    36-inch steel shell pile.............       196/10  167/15 RMS.....................         15.9          2.8           21         11.1          1.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Lf = low frequency, Mf = mid-frequency, Hf = high frequency.

Marine Mammal Occurrence

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information, that 
will inform the take calculations.
    Harbor seal--Limited at-sea densities are available for Pacific 
harbor seals in the Bay. To estimate the number of harbor seals 
potentially taken by Level B harassment, take estimates were developed 
based upon annual surveys of haul outs in the Bay conducted by the 
National Park Service (NPS) (Codde and Allen 2013, 2015, 2017, 2020; 
Codde, 2020). Harbor seals spend more time hauled out and enter the 
water later in the evening during molting season (NPS, 2014). The 
molting season occurs from June-July and overlaps with the construction 
period of June-November, therefore, haul out counts may provide the 
most accurate estimates of harbor seals in the area during that time. 
Due to the close proximity of Castro Rocks to the project area, Chevron 
used the highest mean value of harbor seals observed hauled out at 
Castro Rocks during the molting season in any recent NPS annual survey. 
The highest mean number of harbor seals was recorded in 2019 as 237 
seals. There are no systematic counts available to estimate the number 
of seals that may be in the water near Long Wharf at any given time and 
the number of seals hauled out on Castro Rocks may vary based upon time 
of day, tide, and seal activity. Therefore, the analysis assumes that 
all 237 seals could swim into the Level B harassment zone each day that 
pile driving is occurring.
    California sea lion--Although there are no haul out sites for 
California sea lions in close proximity to the project area, sea lions 
have consistently been sighted in the Bay while monitoring during past 
construction projects (AECOM 2019, 2020, 2021, 2022; Caltrans, 2017). 
As limited data is available on the occurrences of California sea lions 
in the Bay, NMFS used PSO monitoring data from previous stages of the 
LWMEP (AECOM, 2019, 2020, 2021) and Year 1 of the Point Orient Wharf 
Removal (POWR) project (AECOM, 2022) to generate a daily occurrence 
rate. NMFS calculated daily occurrence rate using the following 
equation:

Daily occurrence rate = Total number of animals sighted/Total 
monitoring days

    From 2018-2022, a total of 73 days of monitoring occurred across 
all projects during the seasonal window of June through November. 
During this time, 13 sea lions were sighted. Based upon sightings and 
monitoring days, we calculated a daily occurrence rate of 0.18 sea 
lions per day.
    San Francisco has received a record amount of rainfall since July 
1, 2022 (Bay City News, 2023), indicating that increased freshwater 
inflow into the Bay could be expected this year. The Bay did not 
experience similar freshwater inflow during the LWMEP and POWR years of 
2018-2022. As the impacts of increased freshwater flow into the project 
area on California sea lion occurrences are unclear, and this increased 
freshwater input did not occur during prior monitoring years, we 
conservatively used a daily occurrence rate of California sea lions, 1 
sea lion per day, to estimate take.
    Harbor porpoise--The harbor porpoise population has been growing 
over time in the Bay (Stern et al., 2017). Although commonly sighted in 
the vicinity of Angel Island and the Golden Gate Bridge, approximately 
6 and 12 kilometers (3.7 and 7.5 miles, respectively) southwest of the 
Wharf, individuals may use other areas of central the Bay (Keener, 
2011), as well as the project area. As limited data is available on the 
occurrences of harbor porpoises in the Bay, NMFS used PSO monitoring 
data from previous stages of the LWMEP (AECOM, 2019, 2020, 2021) and 
Year 1 of the Point Orient Wharf Removal (POWR) project (AECOM, 2022) 
to generate a daily occurrence rate. NMFS calculated the daily 
occurrence rate according to the same methods for calculating the daily 
occurrence rate for California sea lions, as described above. From 
2018-2022, a total of 16 harbor porpoises were sighted on 73 monitoring 
days, resulting in a daily occurrence rate of 0.22 harbor porpoises per 
day. Due to the impacts of increased freshwater inflow into the Bay 
(Bay City News, 2023) resulting from elevated rainfall being unclear, 
we conservatively used a higher daily occurrence rate of harbor 
porpoises, 1 porpoise per day, to estimate take.
    Gray whale--Gray whales are often sighted in the Bay during 
February and March, however, pile driving activities are not planned to 
occur during this time. Prior monitoring reports for similar projects 
occurring during the same work windows did not document gray whales in 
the area (AECOM 2019, 2020, 2021). Limited sightings of gray whales in 
the Bay include strandings (Bartlett 2022; TMMC, 2019) and whale watch 
reports (Bartlett, 2022). At-sea densities and regular observational 
data for gray whales in the Bay during the planned project time are not 
available. Although unlikely during the time planned for in-water 
construction activities, Chevron conservatively estimated that up to 
two gray whales may occur in the project area.
    Bottlenose dolphin--The numbers of dolphins in the Bay have been 
increasing over the years (Perlman, 2017; Szczepaniak et al., 2013), 
and a recent study determined that bottlenose dolphins have expanded 
their range to include coastal waters north and south of the Bay 
(Keener et al., 2023). In the Bay, dolphins have been sighted in the 
vicinity of the Golden Gate Bridge, around Yerba Buena and Angel 
Islands, and in the central Bay as far east as Alameda and Point 
Richard (Keener et al., 2023). Although dolphins may occur in the Bay 
year-round, occurrence estimates are limited. Chevron estimated that 
one group of dolphins may enter the Bay once per month. Weller et al. 
(2016) estimated an average group size for coastal bottlenose dolphins 
to be approximately 8.2 dolphins.
    Northern elephant seal--Small numbers of elephant seals may haul 
out or strand within the central Bay (Hern[aacute]ndez, 2020). Previous 
monitoring, however, has shown northern elephant seal densities to be 
very low in the area and, based upon seasonality of occurrences, 
northern elephant seals would be unlikely to occur in the

[[Page 19262]]

project area during the proposed project activities. Additionally, 
northern elephant seals were not observed during pile driving 
monitoring for the LWMEP from 2018-2021 (AECOM, 2018, 2019, 2020, 2021) 
nor for the Point Orient Wharf Removal in 2022 (AECOM, 2022), which was 
located just north of the proposed project area. While it is unlikely 
that northern elephant seals would occur in the project area during the 
months in which work is proposed, Chevron conservatively estimated that 
one northern elephant seal could enter the project area once every 3 
days during in-water construction activities resulting in a total of 10 
northern elephant seals.
    Northern fur seal--The presence of northern fur seals in depends 
upon oceanic conditions, as more fur seals are more likely to range in 
the Bay in search of food and strand during El Ni[ntilde]o events 
(TMMC, 2016). Equatorial sea surface temperatures of the Pacific Ocean 
have been below average across most of the Pacific. La Ni[ntilde]a 
conditions are likely to remain into the spring 2023 after which 
conditions are expected to become more neutral. However, it is unlikely 
El Ni[ntilde]o conditions would develop later in 2023 (NOAA, 2022). 
Northern fur seals were not observed during prior LWMEP monitoring 
(AECOM, 2019, 2020, 2021) nor during the POWRP monitoring (AECOM, 
2022). While it is unlikely that northern fur seals would occur in the 
project areas during in-water activities, Chevron conservatively 
estimated that a maximum of 10 northern fur seals could occur enter the 
project area.

Take Estimation

    Here we describe how the information provided above is synthesized 
to produce a quantitative estimate of the take that is reasonably 
likely to occur and proposed for authorization.
    Take estimate calculations vary by species. To calculate take by 
Level B harassment for harbor seals, California sea lions, and harbor 
porpoises, NMFS multiplied the daily occurrence estimates described in 
the Marine Mammal Occurrence section by the number of project days 
(table 8).
    For bottlenose dolphins, Chevron estimated, and NMFS concurs, that 
one group of 8 bottlenose dolphins may be taken by Level B harassment 
every month of the project. Therefore, Chevron requested, and NMFS 
proposes to authorize, 32 takes of bottlenose dolphins by Level B 
harassment.
    Chevron based requested take by Level B harassment for gray whales 
upon total daily occurrence estimates during the project period. 
Chevron conservatively estimated, and NMFS concurs, that 2 gray whales 
may enter the project area per year. Therefore, Chevron requested, and 
NMFS proposes to authorize, 2 takes of gray whales by Level B 
harassment (table 8).
    For northern elephant seals, Chevron conservatively estimated, and 
NMFS concurs, that one northern elephant seal could enter the project 
area once every 3 days during in-water construction activities. 
Therefore, Chevron requested, and NMFS proposes to authorize, 10 takes 
of northern elephant seals by Level B harassment (table 8).
    Based upon prior occurrences in the Bay, Chevron conservatively 
estimated, and NMFS concurs, that a maximum of 10 northern fur seals 
could occur in the project area during the in-water construction 
activity period. Therefore, Chevron requested, and NMFS proposes to 
authorize 10 takes of northern fur seals by Level B harassment (table 
8).
    Chevron did not request, nor is NMFS proposing to authorize, take 
by Level A harassment. For all pile driving activities, Chevron 
proposed to implement shutdown zones (described further in the Proposed 
Mitigation section) that would be expected to effectively prevent take 
by Level A harassment.

 Table 8--Estimated Take by Level B Harassment Proposed for Authorization and Estimated Take as a Percentage of
                                                 the Population
----------------------------------------------------------------------------------------------------------------
                                                       Estimated take by Level B harassment
                                                            proposed for authorization           Estimated take
            Species                   Expected     --------------------------------------------  as a percentage
                                     occurrence        Impact        Vibratory                    of population
                                                      install     install/extract     Total
----------------------------------------------------------------------------------------------------------------
Harbor seal....................  237 seals per day        4,977             2,133        7,110                23
Sea lion.......................  1 sea lion per              21                 9           30             0.012
                                  day \1\.
Harbor porpoise................  1 harbor porpoise           21                 9           30              0.39
                                  per day \1\.
Bottlenose dolphin.............  Up to 8 dolphins           N/A               N/A           32              1.77
                                  once per month.
Gray whale.....................  2 whales over              N/A               N/A            2             0.007
                                  project duration.
Northern elephant seal.........  1 seal every 3             N/A               N/A           10             0.005
                                  days.
Northern fur seal..............  10 seals over              N/A               N/A           10             0.071
                                  project duration.
----------------------------------------------------------------------------------------------------------------
\1\ Rounded daily occurrence to one individual per day.

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 the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the 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 the 
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, NMFS 
considers 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 would be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;

[[Page 19263]]

    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, and impact on 
operations.
    Chevron must follow mitigation measures as specified below.
    Chevron must ensure that construction supervisors and crews, the 
monitoring team, and relevant Chevron staff are trained prior to the 
start of all pile driving activities, so that responsibilities, 
communication procedures, monitoring protocols, and operational 
procedures are clearly understood. New personnel joining during the 
project must be trained prior to commencing work.

Shutdown Zones

    Chevron must establish shutdown zones for all pile driving 
activities. The purpose of a shutdown zone is generally to define an 
area within which shutdown of the activity would occur upon sighting of 
a marine mammal (or in anticipation of an animal entering the defined 
area). Shutdown zones would be based upon the Level A harassment zone 
for each pile size/type and driving method where applicable, as shown 
in table 7. A minimum shutdown zone of 10 m would be required for all 
in-water construction activities to avoid physical interaction with 
marine mammals. For pile driving, the radii of the shutdown zones are 
rounded to the next largest 10 m interval in comparison to the Level A 
harassment zone for each activity type. If a marine mammal is observed 
entering or within a shutdown zone during pile driving activity, the 
activity must be stopped until there is visual confirmation that the 
animal has left the zone or the animal is not sighted for a period of 
15 minutes. Proposed shutdown zones for each activity type are shown in 
table 9.
    All marine mammals would be monitored in the Level B harassment 
zones and throughout the area as far as visual monitoring can take 
place. If a marine mammal enters the Level B harassment zone, in-water 
activities would continue and PSOs would document the animal's presence 
within the estimated harassment zone.
    Chevron would also establish shutdown zones for all marine mammals 
for which take has not been authorized or for which incidental take has 
been authorized but the authorized number of takes has been met. These 
zones would be equivalent to the Level B harassment zones for each 
activity. If a marine mammal species for which take is not authorized 
or a species for which incidental take has been authorized but the 
authorized number of takes has been met enters the shutdown zone, all 
in-water activities would cease until the animal leaves the zone or has 
not been observed for at least 1 hour, and NMFS would be notified about 
species and precautions taken. Pile removal would proceed if the animal 
is observed to leave the Level B harassment zone or if 1 hour has 
passed since the last observation.
    If shutdown and/or clearance procedures would result in an imminent 
safety concern, as determined by Chevron or its designated officials, 
the in-water activity would be allowed to continue until the safety 
concern has been addressed, and the animal would be continuously 
monitored.

                                                    Table 9--Proposed Shutdown Zones by Activity Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                      Shutdown zones (m) \1\
                 Method                             Pile type            -------------------------------------------------------------------------------
                                                                                LF              MF              HF              PW              OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile removal activities:
    Vibratory extract..................  36-inch steel pile.............              20              10              30              20              10
                                         18-inch concrete pile..........              10              10              10              10              10
Pile installation activities:
    Impact install.....................  24-inch square concrete pile...              40              10              40              20              10
    Vibratory install..................  36-inch steel pile.............              20              10              30              20              10
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Observers would monitor as far as the eye can see.

Protected Species Observers

    The placement of PSOs during all pile driving activities (described 
in the Proposed Monitoring and Reporting section) would ensure that the 
entire shutdown zone is visible. Should environmental conditions 
deteriorate such that the entire shutdown zone would not be visible 
(e.g., fog, heavy rain), pile driving would be delayed until the PSO is 
confident marine mammals within the shutdown zone could be detected.
    PSOs would monitor the full shutdown zones and the Level B 
harassment zones to the extent practicable. 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 
areas outside the shutdown zones and thus prepare for a potential 
cessation of activity should the animal enter the shutdown zone.

Pre- and Post-Activity Monitoring

    Monitoring must take place from 30 minutes prior to initiation of 
pile driving activities (i.e., pre-clearance monitoring) through 30 
minutes post-completion of pile driving. Prior to the start of daily 
in-water construction activity, or whenever a break in pile driving of 
30 minutes or longer occurs, PSOs would observe the shutdown and 
monitoring zones for a period of 30 minutes. The shutdown zone would be 
considered cleared when a marine mammal has not been observed within 
the zone for a 30-minute period. If a marine mammal is observed within 
the shutdown zones listed in table 10, pile driving activity would be 
delayed or halted. If work ceases for more than 30 minutes, the pre-
activity monitoring of the shutdown zones would commence. A 
determination that the shutdown zone is clear must be made during a 
period of good visibility (i.e., the entire shutdown zone and 
surrounding waters must be visible to the naked eye).

Soft-Start Procedures

    Soft-start procedures 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. For 
impact pile driving, contractors would be required to provide an 
initial set of three strikes from the hammer at reduced energy, 
followed by a 30-second waiting period, then two subsequent reduced-
energy strike sets. Soft-start would be implemented at the start of 
each day's

[[Page 19264]]

impact pile driving and at any time following cessation of impact pile 
driving for a period of 30 minutes or longer.

Bubble Curtain

    A bubble curtain must be employed during all impact pile 
installation of the 24-inch square concrete piles to interrupt the 
acoustic pressure and reduce impact on marine mammals. The bubble 
curtain must distribute air bubbles around 100 percent of the piling 
circumference for the full depth of the water column. The lowest bubble 
ring must be in contact with the mudline for the full circumference of 
the ring. The weights attached to the bottom ring must ensure 100 
percent substrate contact. No parts of the ring or other objects may 
prevent full substrate contact. Air flow to the bubblers must be 
balanced around the circumference of the pile.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least 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 would 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 while 
conducting the activities. 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 activity; 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

    Marine mammal monitoring must be conducted in accordance with the 
conditions in this section, the Monitoring Plan, and this IHA. Marine 
mammal monitoring during pile driving activities would be conducted by 
PSO's meeting NMFS' standards and in a manner consistent with the 
following:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor) and have no other assigned tasks 
during monitoring periods;
     At least one PSO would have prior experience performing 
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization;
     Other PSOs may substitute other relevant experience, 
education (degree in biological science or related field), or training 
for prior experience performing the duties of a PSO during construction 
activity pursuant to a NMFS-issued incidental take authorization;
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator must be designated. The lead 
observer must have prior experience performing the duties of a PSO 
during construction activity pursuant to a NMFS-issued incidental take 
authorization; and
     PSOs must be approved by NMFS prior to beginning any 
activity subject to the IHA.
    PSOs should have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     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
     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.
    Chevron would have at least two PSOs stationed at the best possible 
vantage points in the project area to monitor during all pile driving 
activities. Monitoring would occur from elevated locations along the 
shoreline or on barges where the entire shutdown zones and monitoring 
zones are visible. PSOs would be equipped with high quality binoculars 
for monitoring and radios or cells phones for maintaining contact with 
work crews. Monitoring would be conducted 30 minutes before, during, 
and 30 minutes after all in water construction activities. In addition, 
PSOs would record all incidents of marine mammal occurrence, regardless 
of distance from activity, and would document any behavioral reactions 
in concert with distance from piles being driven or removed. 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 30 minutes.
    In addition to monitoring on days that construction would occur, as 
proposed by the applicant, Chevron would conduct biological monitoring 
within one week ahead of the project's start date to establish baseline 
observation. These observation periods would encompass different tide 
levels at different hours of the day.

Data Collection

    Chevron would record detailed information about implementation of 
shutdowns, counts and behaviors (if possible) of all marine mammal 
species observed, times of observations, construction activities that 
occurred, any acoustic and visual disturbances, and weather conditions. 
PSOs would

[[Page 19265]]

use approved data forms to record the following information:
     Date and time that permitted construction activity begins 
and ends;
     Type of pile removal activities that take place;
     Weather parameters (e.g., percent cloud cover, percent 
glare, visibility, air temperature, tide level, Beaufort sea state);
     Species counts, and, if possible, sex and age classes of 
any observed marine mammal species;
     Marine mammal behavior patterns, including bearing and 
direction of travel;
     Any observed behavioral reactions just prior to, during, 
or after construction activities;
     Location of marine mammal, distance from observer to the 
marine mammal, and distance from pile driving activities to marine 
mammals;
     Whether an observation required the implementation of 
mitigation measures, including shutdown procedures and the duration of 
each shutdown; and
     Any acoustic or visual disturbances that take place.

Reporting

    Chevron must submit a draft marine mammal monitoring report to NMFS 
within 90 days after the completion of pile driving activities, or 60 
days prior to the requested issuance of any future IHAs for the 
project, or other projects at the same location, whichever comes first. 
A final report must be prepared and submitted within 30 calendar days 
following receipt of any NMFS comments on the draft report. If no 
comments are received from NMFS within 30 calendar days of receipt of 
the draft report, the report shall be considered final. The marine 
mammal report would include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets and/or raw sighting data. Specifically, the report would 
include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including: (a) How many and what type of piles were 
driven or removed and the method (i.e., impact or vibratory); and (b) 
the total duration of time for each pile (vibratory driving) number of 
strikes for each pile (impact driving);
     PSO locations during marine mammal monitoring; and
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance.
    For each observation of a marine mammal, the following would be 
recorded:
     Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting;
     Time of sighting;
     Identification of the animal(s) (e.g., genus/species, 
lowest possible taxonomic level, or unidentified), PSO confidence in 
identification, and the composition of the group if there is a mix of 
species;
     Distance and location of each observed marine mammal 
relative to pile being driven or removed for each sighting;
     Estimated number of animals (min/max/best estimate);
     Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
     Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses thought to have resulted from the 
activity (e.g., no response or changes in behavioral state such as 
ceasing feeding, changing direction, flushing, or breaching); and
     Animal's closest point of approach and estimated time 
spent within the harassment zone.
    Additionally, Chevron must include the following information in the 
report:
     Number of marine mammals detected within the harassment 
zones, by species; and
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensured, and resulting changes in behavior of the 
animal(s), if any.
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, Chevron would report the 
incident to the Office of Protected Resources (OPR) 
([email protected]), NMFS and to the West Coast 
regional stranding network (866-767-6114) as soon as feasible. If the 
death or injury was clearly caused by the specified activity, Chevron 
would immediately cease the specified activities until NMFS is able to 
review the circumstances of the incident and determine what, if any, 
additional measures are appropriate to ensure compliance with the terms 
of the IHAs. Chevron would not resume their activities until notified 
by NMFS.
    The report would include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

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 impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338; 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the discussion of our analysis applies to all 
the species listed in table 2, given that the anticipated effects of 
this activity on these different marine mammal stocks are expected to 
be similar. There is little information about the nature or severity of 
the impacts, or the size, status, or

[[Page 19266]]

structure of any of these species or stocks that would lead to a 
different analysis for this activity.
    Level A harassment is extremely unlikely given the small size of 
the Level A harassment isopleths and the required mitigation measures 
designed to minimize the possibility of injury to marine mammals. No 
serious injury or mortality is anticipated given the nature of the 
activity.
    Pile driving activities have the potential to disturb or displace 
marine mammals. Specifically, the project activities may result in 
take, in the form of Level B harassment from underwater sounds 
generated from impact and vibratory pile driving activities. Potential 
takes could occur if individuals move into the ensonified zones when 
these activities are underway.
    The takes by Level B harassment would be due to potential 
behavioral disturbance. The potential for harassment is minimized 
through construction methods and the implementation of planned 
mitigation strategies (see Proposed Mitigation section).
    Take would occur within a limited, confined area of each stock's 
range. Further, the amount of take authorized is extremely small when 
compared to stock abundance.
    No marine mammal stocks for which take is proposed are listed as 
threatened or endangered under the ESA or determined to be strategic or 
depleted under the MMPA. The relatively low marine mammal occurrences 
in the area, small shutdown zones, and planned monitoring make injury 
takes of marine mammals unlikely. The shutdown zones would be 
thoroughly monitored before the pile driving activities begin, and 
activities would be postponed if a marine mammal is sighted within the 
shutdown zone. There is a high likelihood that marine mammals would be 
detected by trained observers under environmental conditions described 
for the project. Limiting construction activities to daylight hours 
would also increase detectability of marine mammals in the area. 
Therefore, the mitigation and monitoring measures are expected to 
eliminate the potential for injury and Level A harassment as well as 
reduce the amount and intensity of Level B 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 occurred with no reported injuries 
or mortality to marine mammals, and no known long-term adverse 
consequences from behavioral harassment.
    Anticipated and authorized takes are expected to be limited to 
short-term Level B harassment (behavioral disturbance) as construction 
activities would occur intermittently over the course of 30 days. 
Effects on individuals taken by Level B harassment, based upon reports 
in the literature as well as monitoring from other similar activities, 
may include increased swimming speeds, increased surfacing time, 
increased haul out time by pinnipeds, or decreased foraging (e.g., 
Thorson and Reyff, 2006; NAVFAC SW, 2018b). Individual animals, even if 
taken multiple times, would likely move away from the sound source and 
be temporarily displaced from the area due to elevated noise level 
during pile removal. Marine mammals could also experience TTS if they 
move into the Level B harassment zone. TTS is a temporary loss of 
hearing sensitivity when exposed to loud sound, and the hearing 
threshold is expected to recover completely within minutes to hours. 
Thus, it is not considered an injury. While TTS could occur, it is not 
considered a likely outcome of this activity. Repeated exposures of 
individuals to levels of sounds that could cause Level B harassment are 
unlikely to considerably significantly disrupt foraging behavior or 
result in significant decrease in fitness, reproduction, or survival 
for the affected individuals. In all, there would be no adverse impacts 
to the stock as a whole.
    As previously described, a UME has been declared for Eastern 
Pacific gray whales. However, we do not expect proposed takes for 
authorization in this action to exacerbate the ongoing UME. As 
mentioned previously, no injury or mortality is proposed for 
authorization, and take by Level B harassment is limited (2 takes over 
the duration of the project). Therefore, we do not expect the proposed 
take authorization to compound the ongoing UME.
    The project is not expected to have significant adverse effects on 
marine mammal habitat. There are no known Biologically Important Areas 
(BIAs) or ESA-designated critical habitat within the project area, and 
the activities would not permanently modify existing marine mammal 
habitat. Although harbor seal haul out sites are located in the Bay, 
hauled out seals are not likely to be impacted. PSOs during the seismic 
retrofit of the Richmond Bridge did not note any decline in use by 
harbor seals at Castro Rocks, a haul out site which is approximately 20 
to 100 m from the bridge (Greene et al., 2006) and 560 m from the 
project area. In addition, any pupping that may occur at Castro Rocks 
would take place outside of the work window for the proposed pile 
driving activities. 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, however, due to the short 
duration of 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.
    In combination, these factors, as well as the available body of 
evidence from other similar activities, demonstrate that the potential 
effects of the specified activities would have only minor, short-term 
effects on individuals. The specified activities are not expected to 
impact reproduction or survival of any individual marine mammals, much 
less have impacts on annual rates of recruitment or survival.
    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 any of the species 
or stocks through effects on annual rates of recruitment or survival:
     No serious injury, mortality, or Level A harassment is 
anticipated or proposed for authorization;
     The specified activities and associated ensonified areas 
are very small relative to the overall habitat ranges of all species;
     The project area does not overlap known BIAs or ESA-
designated critical habitat;
     The lack of anticipated significant or long-term effects 
to marine mammal habitat;
     The presumed efficacy of the mitigation measures in 
reducing the effects of the specified activity; and
     Monitoring reports from similar work in the Bay have 
documented little to no effect on individuals of the same species 
impacted by the specified activities.
    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 would have a negligible impact 
on all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for

[[Page 19267]]

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. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The amount of take NMFS has authorized is below one-third of the 
estimated stock abundances for all seven stocks (refer back to table 
8). For most stocks, the proposed take of individuals is less than 2 
percent of the abundance of the affected stock (with exception for 
harbor seals at 23 percent). This is likely a conservative estimate 
because it assumes all takes are of different individual animals, which 
is likely not the case for harbor seals, given the nearby haulout. Some 
individuals may return multiple times in a day, but PSOs would count 
them as separate takes if they cannot be individually identified.
    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 would 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 
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

    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 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's for conducting pile driving activities in San 
Francisco Bay from June 1, 2023 through November 30, 2023, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. A draft of the proposed IHA can be found at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed 
construction project. We also request comment on the potential renewal 
of this proposed IHA as described in the paragraph below. Please 
include with your comments any supporting data or literature citations 
to help inform decisions on the request for this IHA or a subsequent 
renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, 1 year renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical activities as described in the Description of Proposed 
Activities section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activities section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (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 will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: March 28, 2023.
Catherine Marzin,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2023-06744 Filed 3-30-23; 8:45 am]
BILLING CODE 3510-22-P