Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Chevron Long Wharf Maintenance and Efficiency Project in San Francisco Bay, California, 31703-31715 [2023-10623]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 96 (Thursday, May 18, 2023)]
[Notices]
[Pages 31703-31715]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-10623]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC916]


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

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

ACTION: Notice; issuance of incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
the NMFS has issued an incidental harassment authorization (IHA) to 
Chevron Products Company (Chevron) to incidentally harass, by Level B 
harassment only, marine mammals during construction activities 
associated with the Long Wharf Maintenance and Efficiency Project 
(LWMEP) in San Francisco Bay, California.

DATES: This authorization is effective from June 1, 2023 through May 
31, 2024.

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,

[[Page 31704]]

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.

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.
    The IHA will 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.
    There are no changes from the proposed IHA to the final IHA.

Description of 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 project, Chevron will use vibratory 
extraction to remove concrete piles associated with the existing 
gangway and catwalk. Impact hammers will 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 will be installed through the use of a vibratory hammer and 
removed by vibratory extraction when in-water construction activities 
are complete. The Long Wharf 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 will take place within the seasonal work window of June 1, 
2023 through November 30, 2023. Unless otherwise specified, the term 
``pile driving'' may refer to either pile installation or removal.
    Chevron's 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 authorized.
    A detailed description of the planned construction project is 
provided in the Federal Register notice for the proposed IHA (88 FR 
19247, March 31, 2023). Since that time, no changes have been made to 
the planned construction activities. Therefore, a detailed description 
is not provided here. Please refer to that Federal Register notice for 
a description of the specific activity. Mitigation, monitoring, and 
reporting measures are described in detail later in this document 
(please see Mitigation and Monitoring and Reporting).

Comments and Responses

    A notice of NMFS' proposal to issue an IHA to Chevron was published 
in the Federal Register on March 31, 2023 (88 FR 19237). That notice 
described, in detail, Chevron's activity, the marine mammal species 
that may be affected by the activity, and the anticipated effects on 
marine mammals. In that notice, we requested public input on the 
request for authorization described therein, our analyses, the proposed 
authorization, and any other aspect of the notice of proposed IHA, and 
requested that interested persons submit relevant information, 
suggestions, and comments. During the 30-day public comment period, 
NMFS did not receive any public comments.

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, 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 1 lists all species or stocks for which take is expected and 
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

[[Page 31705]]

or authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species 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 1 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 1--Marine Mammal Species \4\ Likely To Be Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                       Stock abundance
                                                                                 ESA/MMPA status;      (CV, Nmin, most                      Annual M/SI
           Common name                Scientific name            Stock          strategic (Y/N) \1\    recent abundance         PBR             \3\
                                                                                                         survey) \2\
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                                            Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray whale...................  Eschrichtius          Eastern North         -, -, N.............  26,960 (0.05,                   801             131
                                    robustus.             Pacific.                                    25,849, 2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Bottlenose dolphin...........  Tursiops truncatus..  California Coastal..  -, -, N.............  453 (0.06, 346,                 2.7           >=2.0
                                                                                                      2011).
Family Phocoenidae (porpoises):
    Harbor porpoise..............  Phocoena phocoena...  San Francisco/        -, -, N.............  7,777 (0.62, 4,811,              73           >=0.4
                                                          Russian River.                              2017).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    California sea lion..........  Zalophus              U.S.................  -, -, N.............  257,606 (N/A,                14,011            >321
                                    californianus.                                                    233,515, 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,                  1,641              43
                                                                                                      27,348, 2012).
    Northern elephant seal.......  Mirounga              California Breeding.  -, -, N.............  187,386 (N/A,                 5,122            13.7
                                    angustirostris.                                                   85,369, 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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.

    As indicated above, all seven species (with seven 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 project area 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 activities.
    A detailed description of the species likely to be affected by the 
pile driving activities, including brief introductions to the species 
and relevant stocks as well as available information regarding 
population trends and threats, and information regarding local 
occurrence,

[[Page 31706]]

were provided in the Federal Register notice for the proposed IHA (88 
FR 19247, March 31, 2023); since that time, we are not aware of any 
changes in the status of these species and stocks; therefore, detailed 
descriptions are not provided here. Please refer to that Federal 
Register notice for these descriptions. Please also refer to NMFS' 
website (https://www.fisheries.noaa.gov/find-species) for generalized 
species accounts.

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 2.

                  Table 2--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (sea lions 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

    The effects of underwater noise from Chevron's pile driving 
activities have the potential to result in behavioral harassment of 
marine mammals in the vicinity of the project area. The notice of the 
proposed IHA (88 FR 19247, March 31, 2023) included a discussion of the 
effects of anthropogenic noise on marine mammals and the potential 
effects of underwater noise from Chevron's pile driving activities on 
marine mammals and their habitat. That information and analysis is 
incorporated by reference into this final IHA determination and is not 
repeated here; please refer to the notice of the proposed IHA (88 FR 
19247, March 31, 2023).

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
authorized through this IHA, which informed 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, protected species observers (PSOs) 
monitoring) discussed in detail below in the Mitigation section, Level 
A harassment is neither anticipated nor authorized.
    As described previously, no serious injury or mortality is 
anticipated or authorized for this activity. Below, we describe how the 
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 take estimates.

[[Page 31707]]

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 permanent threshold shift (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 
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 RMS 
pressure received levels (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 temporary threshold shift (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 pile driving 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 
pile driving 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 3--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: 219   Cell 2: LE,p,LF,24h: 199 dB.
                                          dB; LE,p,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lp,0-pk,flat: 230   Cell 4: LE,p,MF,24h: 198 dB.
                                          dB; LE,p,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lp,0-pk,flat: 202   Cell 6: LE,p,HF,24h: 173 dB.
                                          dB; LE,p,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lp,0-pk,flat: 218   Cell 8: LE,p,PW,24h: 201 dB.
                                          dB; LE,p,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lp,0-pk,flat: 232   Cell 10: LE,p,OW,24h: 219 dB.
                                          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, will 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 removal and 
installation activities derived from this review are shown in Table 4.

[[Page 31708]]



                                           Table 4--Source Levels for Pile Removal and Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Source levels (dB)/source distance (m)
                                                             ---------------------------------------------------------
               Method                        Pile type            Peak sound      Mean maximum RMS                                 Reference
                                                              pressure (dB re 1     SPL (dB re 1     SEL \1\ (dB re 1
                                                                   [mu]Pa)            [mu]Pa)          [mu]Pa2 sec)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact install \2\..................  24-inch square                     191/10             173/10             161/10  AECOM (2018, 2019).
                                       concrete pile.
Vibratory install/extract...........  36-inch steel shell                196/10             167/15                167  AECOM (2019).
                                       pile.
Vibratory extract \3\...............  18-inch concrete pile.                N/A             163/10                150  NAVFAC SW (2022).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Sound exposure level (SEL).
\2\ Chevron will use a bubble curtain attenuation system for all impact pile driving. NMFS conservatively assumes that the bubble curtain will result in
  a 5 dB reduction in sound. These source levels incorporate the 5 dB reduction.
\3\ 20-inch concrete piles used as a proxy as vibratory data for 18-inch concrete piles was not available.

    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 activities are shown in Table 5.

                     Table 5--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 of the

[[Page 31709]]

Federal Register notice for the proposed IHA (88 FR 19247, March 31, 
2023). The maximum RMS SPL/SEL SPL as well as peak SPL and resulting 
isopleths are reported below in Table 6. 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 6--Distance to Level A Harassment Thresholds for Each Marine Mammal Hearing Group
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                     Source levels (dB)/source distance                    Distances to level A harassment threshold (m)
                                                    (m)                  -------------------------------------------------------------------------------
            Pile type             ---------------------------------------                                                     Phocid          Otariid
                                        Peak              RMS/SEL          Lf cetaceans    Mf cetaceans    Hf 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
    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 haulouts 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, haulout 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 haulout 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, 
one 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, one 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,

[[Page 31710]]

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 project area 
during the 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 project area. While it is unlikely that northern elephant seals 
would occur in the project area during the months in which work is 
planned, Chevron conservatively estimated that 1 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 of 2023, after which 
conditions are expected to become more neutral. However, it is unlikely 
El Ni[ntilde]o conditions will 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.
    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 7).
    For bottlenose dolphins, Chevron estimated, and NMFS concurs, that 
one group of eight bottlenose dolphins may be taken by Level B 
harassment every month of the project. Therefore, Chevron requested, 
and NMFS has authorized, 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 two gray 
whales may enter the project area per year. Therefore, Chevron 
requested, and NMFS has authorized, two takes of gray whales by Level B 
harassment (Table 7).
    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 has authorized, 10 takes of 
northern elephant seals by Level B harassment (Table 7).
    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 has authorized 
10 takes of northern fur seals by Level B harassment (Table 7).
    Chevron did not request, nor has NMFS authorized, take by Level A 
harassment. For all pile driving activities, Chevron will to implement 
shutdown zones (described further in the Mitigation section) that are 
expected to effectively prevent take by Level A harassment.

       Table 7--Authorized Take by Level B Harassment and Estimated Take as a Percentage of the Population
----------------------------------------------------------------------------------------------------------------
                                                       Authorized take by level B harassment
                                                 ------------------------------------------------ Estimated take
            Species                 Expected                         Vibratory                         as a
                                   occurrence     Impact install     install/          Total       percentage of
                                                                      extract                       population
----------------------------------------------------------------------------------------------------------------
Harbor seal...................  237 seals per              4,977           2,133           7,110              23
                                 day.
Sea lion......................  1 sea lion per                21               9              30           0.012
                                 day \1\.
Harbor porpoise...............  1 harbor                      21               9              30            0.39
                                 porpoise 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.

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,

[[Page 31711]]

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;
    (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 will occur upon sighting of 
a marine mammal (or in anticipation of an animal entering the defined 
area). Shutdown zones will be based upon the Level A harassment zone 
for each pile size/type and driving method where applicable, as shown 
in Table 6. A minimum shutdown zone of 10 m will 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. Shutdown zones for each activity type are shown in Table 8.
    All marine mammals will 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 will continue and PSOs will document the animal's presence 
within the estimated harassment zone.
    Chevron will 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 will 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 must cease until the animal leaves the zone or has 
not been observed for at least 1 hour, and NMFS will be notified about 
species and precautions taken. Pile removal will 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 will result in an imminent 
safety concern, as determined by Chevron or its designated officials, 
the in-water activity will be allowed to continue until the safety 
concern has been addressed, and the animal will be continuously 
monitored.

                                                        Table 8--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 will monitor as far as the eye can see.

Protected Species Observers

    The placement of PSOs during all pile driving activities (described 
in the Monitoring and Reporting section) will ensure that the entire 
shutdown zone is visible. Should environmental conditions deteriorate 
such that the entire shutdown zone will not be visible (e.g., fog, 
heavy rain), pile driving will be delayed until the PSO is confident 
marine mammals within the shutdown zone could be detected.
    PSOs will 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-

[[Page 31712]]

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 will observe the shutdown and monitoring 
zones for a period of 30 minutes. The shutdown zone will 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 will be delayed or 
halted. If work ceases for more than 30 minutes, the pre-activity 
monitoring of the shutdown zones will 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 will 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 will be implemented at the start of each day's impact 
pile driving and at any time following cessation of impact pile driving 
for a period of 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 planned measures, NMFS 
has determined that the 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.

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 will 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 will 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 will have at least two PSOs stationed at the best possible 
vantage points in the project area to monitor during all pile driving 
activities. Monitoring will occur from elevated locations along the 
shoreline or on barges where the entire shutdown zones and monitoring 
zones are visible. PSOs will be equipped with high quality binoculars 
for monitoring and radios or cells phones for maintaining contact

[[Page 31713]]

with work crews. Monitoring will be conducted 30 minutes before, 
during, and 30 minutes after all in water construction activities. In 
addition, PSOs will record all incidents of marine mammal occurrence, 
regardless of distance from activity, and will 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 will occur, as 
planned by the applicant, Chevron will conduct biological monitoring 
within 1 week ahead of the project's start date to establish baseline 
observation. These observation periods will encompass different tide 
levels at different hours of the day.

Data Collection

    Chevron will 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 will 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 will 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 will 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 will 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 will 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 
will 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 must not resume their activities until notified by 
NMFS.
    The report will 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

[[Page 31714]]

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 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 will be due to potential behavioral 
disturbance. The potential for harassment is minimized through 
construction methods and the implementation of planned mitigation 
strategies (see Mitigation section).
    Take will 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 authorized 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 will be thoroughly 
monitored before the pile driving activities begin, and activities will 
be postponed if a marine mammal is sighted within the shutdown zone. 
There is a high likelihood that marine mammals will be detected by 
trained observers under environmental conditions described for the 
project. Limiting construction activities to daylight hours will 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 will 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, will 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 will be no adverse impacts 
to the stock as a whole.
    As previously described, an Unusual Mortality Event (UME) has been 
declared for Eastern Pacific gray whales. However, we do not expect 
authorized takes in this action to exacerbate the ongoing UME. As 
mentioned previously, no injury or mortality is authorized, and take by 
Level B harassment is limited (two takes over the duration of the 
project). Therefore, we do not expect the 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 will not permanently modify existing marine mammal 
habitat. Although harbor seal haulout 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 haulout 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 
will take place outside of the work window for the 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 will 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 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 authorized;

[[Page 31715]]

     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 monitoring and mitigation 
measures, NMFS finds that the total marine mammal take from the 
activity will 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 
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 authorized take of individuals is less than 2 
percent of the abundance of the affected stock (with exception of 
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 will count 
them as separate takes if they cannot be individually identified.
    Based on the analysis contained herein of the activity (including 
the mitigation and monitoring measures) and the anticipated take of 
marine mammals, NMFS finds that small numbers of marine mammals will be 
taken relative to the population size of the affected species or 
stocks.

Unmitigable Adverse Impact Analysis and Determination

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

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 determined 
that the issuance of the IHA qualifies to be categorically excluded 
from further NEPA review.

Authorization

    NMFS has issued an IHA to Chevron for the potential harassment of 
small numbers of seven marine mammal species incidental to the LWMEP in 
San Francisco Bay, California, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are followed.

    Dated: May 15, 2023.
Shannon Bettridge,
Chief, Marine Mammal and Sea Turtle Conservation Division, Office of 
Protected Resources, National Marine Fisheries Service.
[FR Doc. 2023-10623 Filed 5-17-23; 8:45 am]
BILLING CODE 3510-22-P