Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Pacific Gas & Electric Sediment Remediation Project, San Francisco Bay, 82836-82856 [2023-26012]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 226 (Monday, November 27, 2023)]
[Notices]
[Pages 82836-82856]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-26012]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD458]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Pacific Gas & Electric Sediment 
Remediation Project, San Francisco Bay

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from Pacific Gas & Electric 
Company (PG&E) for authorization to take marine mammals incidental to 
construction associated with a sediment remediation project 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 December 
27, 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]. 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.
    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 https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities 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.
    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 below.

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

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

[[Page 82837]]

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 May 4, 2023, NMFS received a request from PG&E for an IHA to 
take marine mammals incidental to a Sediment Remediation Project in 
Remedial Response Areas A and B, Piers 39 to 43\1/2\, San Francisco 
Bay. Following NMFS' review of the application, PG&E submitted 
additional information on July 25, 2023 and September 26, 2023 and 
subsequently submitted a revised application on November 16, 2023, 
which was deemed adequate and complete. PG&E's request is for take of 
seven species (eight stocks) of marine mammals by Level B harassment 
only. Neither PG&E nor NMFS expect serious injury or mortality to 
result from this activity and, therefore, an IHA is appropriate.
    This proposed IHA would cover 1 year of a larger project for which 
PG&E intends to request take authorization for subsequent facets of the 
project if necessary. The larger 5-7 year project involves construction 
to remediate contaminated sediment.

Description of Proposed Activity

Overview

    PG&E is proposing to remediate sediments impacted with polycyclic 
aromatic hydrocarbons (PAHs) in San Francisco Bay around the area 
offshore of Pier 43\1/2\ to the east of Pier 45 and offshore area of 
Pier 43. As part of the proposed project, PG&E is proposing to use 
primarily vibratory pile driving to install steel piles for a turbidity 
curtain and temporary relocation of the Red and White Fleet (RWF) and 
wood or composite piles for slope stabilization. Impact pile driving 
would only be used as needed to seat these piles. In addition, PG&E 
plans to use impact pile driving to install composite plastic piles as 
part of a hydroacoustic data collection. Vibratory and impact pile 
driving would introduce underwater sounds that may result in take, by 
Level B harassment, of marine mammals. This proposed IHA would 
authorize take for Year 1 of the project, which is scheduled to begin 
in spring of 2024.
    PG&E'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. No Level A harassment is 
anticipated to occur, and none is proposed for authorization.

Dates and Duration

    The proposed IHA would be effective from May 1, 2024 to April 30, 
2025. Up to 50 days of pile driving are expected, which includes a 10% 
buffer for possible delays (See table 1). Work is expected to occur 6 
days a week over an 11 hour workday. Pile driving would be completed 
only during the daylight hours. The majority of pile driving will be 
through vibratory methods. Any impact pile driving is restricted to 
occur from June 1 to November 30 to protect sensitive life stages of 
listed fish species in the area.

Specific Geographic Region

    The Project Area is situated in the San Francisco Bay, about 3.7 
miles (mi) (6 km) from the entrance. The Project Area encompasses Pier 
39, both the Pier 39 East and West Basins, defined by existing 
breakwaters, and the intertidal and subtidal areas between Pier 39 and 
45 along the margin of San Francisco Bay. The Project Area is divided 
into five remedial response areas. This IHA is for work being done in 
Remedial Response Areas A and B. Remedial Response Area A is Pier 43\1/
2\ offshore area and western limit of the remedial response areas to 
the east of Pier 45, and Remedial Response Area B is Pier 43 offshore 
area which includes two subareas (B1 and B2) (See Figure 1). All of the 
pile driving during the timeframe of this IHA will be in Remedial 
Response Area A except for the installation of eight turbidity curtain 
piles in Remedial Response Area B.
BILLING CODE 3510-22-P

[[Page 82838]]

[GRAPHIC] [TIFF OMITTED] TN27NO23.002

BILLING CODE 3510-22-C
Figure 1--Project Location

Detailed Description of the Specified Activity

    PG&E proposes to remediate sediments impacted with PAHs in order to 
protect human health and the environment. As noted above, this proposed 
IHA would authorize take associated with Year 1 of the Project only. 
This Project is expected to occur over a period of 5-7 years, and the 
phases will occur from west to east in the Project Area.
    PG&E expects that Year 1 of the Project will include installation 
of hydroacoustic data collection piles; installation of piles to attach 
a turbidity curtain; dredging of impacted sediment; installation of 
sediment pins to promote slope stability; capping of impacted sediment 
to be left in place; placement of armoring as needed; and relocation of 
the RWF, which will require the installation and removal of piles.
    PG&E expects, and NMFS concurs, that only pile driving activities 
will result in harassment of marine mammals. Underwater noises 
generated by dredging and capping is similar and within range of other 
background noise in San Francisco Bay and not anticipated to result in 
take of marine mammals.
    Activities that are expected to result in take are described below 
and in table 2:
     Hydroacoustic Data Collection--In order to collect 
hydroacoustic data, up to 10 18-inch composite plastic piles may be 
driven with an impact hammer during the approved anadromous fish work 
window between June 1 and November 30. The piles will be removed using 
vibratory methods.
     Turbidity Curtain--During active dredging and capping 
operations, a turbidity curtain would be deployed across the full depth 
of the water column to minimize the potential for material loss outside 
the remedial response area. The turbidity curtain

[[Page 82839]]

would be attached to 20 temporary piles. These piles would consist of 
either H-piles or steel shell piles less than or equal to 24 inches (61 
cm) in diameter and would be installed using vibratory pile driving. 
These piles would be removed using vibratory methods.
     RWF Temporary Relocation--Relocation of the RWF would 
require removal of piles and overwater structures at the current 
location. Facilities would be reconstructed to the east side of Pier 
45, which would require placement of eight 36-inch diameter guide piles 
and eight 24-inch diameter fender piles. All piles will be installed 
primarily using vibratory methods. If an impact hammer is required to 
seat piles, it would be restricted to only piles less than or equal to 
24 inches (61 cm) in diameter, and attenuation (e.g., bubble curtain) 
would be used. Work would be restricted to June 1 to November 30 for 
impact pile driving.
     Slope stabilization--Approximately 120, 14 to 16-inch 
diameter tapered wood or composite sediment pins would be permanently 
installed using primarily vibratory methods with impact installation as 
needed to seat the piles.

                                   Table 1--Schedule of In-Water Construction
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                                                                             Number of piles      Days of pile
                Type of pile                      Total number of pile          installed/         driving or
                                                  installation/removal       removed per day        removal
----------------------------------------------------------------------------------------------------------------
Turbidity Curtain (Steel H-Piles or Steel    40 (20 installed, 20 removed)                  4                 10
 Shell Pile <=24 inches).
RWF Temporary Relocation (Steel Shell Pile   32 (16 installed, 16 removed)                  4                  8
 <=24 inches and 36 in Steel Shell Piles).
Sediment Pin Installation (14 to 16-inch     120 (installation only)......                  7               * 17
 timber or plastic).
Hydroacoustic Data Collection Piles (18-     20 (10 installed, 10 removed)                  2                 10
 inch composite).
                                            --------------------------------------------------------------------
    Total..................................  180..........................  .................                 45
                                                                           -------------------------------------
        Total (+10% buffer)................  .............................               * 50
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* Rounded to maximum number of full days.


                                     Table 2--Pile Installation Information
----------------------------------------------------------------------------------------------------------------
                                                                                   Duration per
          Pile type                 Method         Number piles    Max piles/day       pile         Strikes per
                                                                                     (minutes)         pile
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                                          Hydroacoustic Data Collection
----------------------------------------------------------------------------------------------------------------
18-inch composite/plastic....  Impact            10.............              10             N/A             400
                                Installation.
18-inch composite/plastic....  Vibratory         10.............              10               5             N/A
                                removal.
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                                              Turbidity Curtain \1\
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Steel H-Pile.................  Vibratory         20 installed                  4              10             N/A
                                installation      and removed.
                                and removal.
Steel Shell Pile <=24 inches.  Vibratory         20 installed                  4              10             N/A
                                installation      and removed.
                                and removal.
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                                         RWF Temporary Relocation Piles
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Steel Shell Pile <=24 inches.  Vibratory         16 (8                         4              10             N/A
                                installation      installed, 8
                                and removal.      removed).
Steel Shell Pile <=24 inches.  Impact            8..............               4             N/A             400
                                installation if
                                needed.
Steel Shell Pile 36 inches...  Vibratory         16 (8                         4              20             N/A
                                installation      installed, 8
                                and removal.      removed).
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                                                Sediment Pins \2\
----------------------------------------------------------------------------------------------------------------
14 to 16-inch Timber.........  Vibratory         120............              20              20             N/A
                                installation.
14 to 16-inch Composite/       Vibratory         120............              10              20             N/A
 Plastic.                       installation.
14 to 16-inch Timber or 14 to  Impact install    120............              10             N/A             400
 16-inch Composite/Plastic.     if needed.
----------------------------------------------------------------------------------------------------------------
\1\ Turbidity curtain piles will either be H piles or steel shell piles less than or equal to 24 inches in
  diameter.
\2\ The sediment pins will either be timber or composite/plastic.

    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

[[Page 82840]]

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; https://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 3 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 and Alaska SARs. All values presented in table 3 are 
the most recent available at the time of publication and are available 
online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                     Table 3--Marine Mammal Species Likely Impacted by the Specified Activities \1\
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                                                                                         ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \2\          abundance survey) \3\               SI \4\
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Family Delphinidae:
    Bottlenose dolphin..............  Tursiops truncatus.....  Coastal California.....  -,-,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, 4811,             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.  United States..........  -,-,N               257,606 (N/A, 233,515,     14,011      >=321
                                                                                                             2014).
    Northern Fur Seal...............  Callorhinus ursinus....  California.............  -,-,N               14,050 (0.03, 7,524,          451        1.8
                                                                                                             2013).
    Northern Fur Seal...............  Callorhinus ursinus....  Eastern North Pacific..  -, D, Y             626,618 (0.2, 530,376,     11,403        373
                                                                                                             2021).
    Steller Sea Lion................  Eumetopias jubatus.....  Eastern North Pacific..  -,-,N               43,201 (N/A, 43,201,        2,592        112
                                                                                                             2017).
Family Phocidae (earless seals):
    Harbor Seal.....................  Phoca vitulina.........  California.............  -,-,N               30,968 (N/A, 27,348,        1,641         43
                                                                                                             2014).
    Northern Elephant Seal..........  Mirounga angustirostris  California Breeding....  -,-,N               187,386 (N/A, 85,369,       5,122       13.7
                                                                                                             2013).
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\1\ 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)).
\2\ 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.
\3\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ 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, vessel strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.

    As indicated above, all seven species (with eight managed stocks) 
in table 3 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. Gray whales and 
humpback whales rarely enter the Bay but may occasionally pass offshore 
of the Project Area. However, if either of these species are to 
approach the Level B zone construction will be shutdown. Therefore, no 
take is expected of these species, and these species will not be 
discussed further.

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., 2023).
    Harbor seals are the most common marine mammal species observed in 
the Bay and occur year-round. Within the Bay they primarily use 
haulouts on exposed rocky ledges and on sloughs in the southern Bay. 
Harbor seals are central-place foragers (Orians and Pearson 1979) and 
tend to exhibit strong site fidelity within season and across years, 
generally forage close to haulout sites, and repeatedly visit specific 
foraging areas (Grigg et al., 2012; Suryan

[[Page 82841]]

and Harvey, 1998; Thompson et al., 1998). Harbor seals in the Bay 
forage mainly within 7 mi (11.3 kilometers (km)) of their primary 
haulout site (Grigg et al. 2012), and often within just 1-3 mi (1-5 km; 
Torok 1994). Harbor seals tend to forage at night and return to the 
haulout during the day with the peak in the afternoon between 1 p.m. 
and 4 p.m. (London et al, 2001; Stewart and Yochem, 1994; Yochem et al, 
1987).
    The closest harbor seal haulout to the Project Area is Yerba Buena 
Island (YBI), approximately 4 km to the east of the Project Area. 
Although the YBI haulout is not expected to be within the area of 
ensonification, it is likely that foraging seals from this location 
would be present in the water during construction.

Northern Elephant Seal

    Northern elephant 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., 2023). They are common on California coastal 
mainland and island sites, where they pup, breed, rest, and molt. 
Northern elephant seals haul out to give birth and breed from December 
through March. Near the Bay, elephant seals breed, molt, and use the 
A[ntilde]o Nuevo Island haulout site, the Farallon Islands, and Point 
Reyes National Seashore. Northern elephant seals do not have any 
established haulout sites in the Bay. Generally, only juvenile elephant 
seals enter the Bay seasonally and do not remain long if they are 
healthy. 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., 2023).

California Sea Lion

    California sea lions are found from Vancouver Island, British 
Columbia, to the southern tip of Baja California. Sea lions breed on 
the offshore islands of southern and central California from May 
through July (Heath and Perrin, 2008). During the non-breeding season, 
adult and subadult males and juveniles migrate northward along the 
coast to central and northern California, Oregon, Washington, and 
Vancouver Island (Jefferson, et al. 1993). Females and some juveniles 
tend to remain closer to rookeries (Atonelis et al., 1990; Melin et 
al., 2008).
    California sea lions have occupied K-Dock at Pier 39 in the Bay, 
adjacent to Area D of the Project Area, since 1987. No pupping has been 
observed here or at any other site in the Bay. Pier 39 is the only 
regularly used haulout site in the Project vicinity, but sea lions 
occasionally use human-made structures such as bridge piers, jetties, 
or navigation buoys (Riedman, 1990) as a haulout location.
    California sea lions feed seasonally on schooling fish and 
cephalopods, including salmon, herring, sardines, anchovy, mackerel, 
whiting, rockfish and squid (Lowry et al., 1990, 1991, 2022; Weise 
2000; Carretta et al., 2023) and can be seen foraging throughout the 
Bay. 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. 2023).

Northern Fur Seal

    Two northern fur seal stocks may occur near the Bay: the California 
and Eastern North Pacific stocks. The California stock breeds and pups 
on the offshore islands of California, and forages off the California 
coast. The Eastern Pacific stock breeds and pups on islands in the 
North Pacific Ocean and Bering Sea, but females and juveniles move 
south to California waters to forage in the fall and winter months 
(Gelatt and Gentry, 2018). Both the California and Eastern North 
Pacific stocks forage in the offshore waters of California, but usually 
only sick or emaciated juvenile fur seals seasonally enter the Bay in 
the fall and winter. Fur seals occasionally strand on YBI and Treasure 
Island, approximately 3.2 km from the Project Area.

Steller Sea Lion

    Steller sea lions range along the North Pacific Rim from northern 
Japan to California. The eastern stock of Steller sea lions has 
historically bred on rookeries located in Southeast Alaska, British 
Columbia, Oregon, and California. Within the last several years a new 
rookery has become established on the outer Washington coast (Muto et 
al., 2020). The Steller sea lion is not common in the Bay, but 
occasionally Steller sea lions can be seen hauled out on Pier 39. Most 
recently, an adult male Steller sea lion was seen on the K-dock haulout 
in May 2023 (Segura, 2023).

Bottlenose Dolphin

    Bottlenose dolphins are distributed world-wide in tropical and 
warm-temperate waters. The California coastal stock of common 
bottlenose dolphin is found within 0.6 mi (1 km) of shore (Defran and 
Weller, 1999) and occurs from northern Baja California, Mexico to 
Bodega Bay, CA. Their range has extended north over the last several 
decades with El Ni[ntilde]o events and increased ocean temperatures 
(Hansen and Defran, 1990) and spans as far north as Sonoma County 
(Keener et al., 2023). As the range of bottlenose dolphins extended 
north, dolphins began entering the Bay in 2010 (Szczepaniak, 2013). 
Bottlenose dolphins have been regularly observed in the western Central 
and South Bay, and between one and five dolphins are thought to be 
year-round residents of the Bay (Pacific Gas & Electric, 2023). An 
offshore common bottlenose dolphin stock exists, but genetic studies 
show that no mixing occurs between the two stocks (Lowther-Thieleking 
et al., 2015). Bottlenose dolphins are opportunistic foragers, and time 
of day, tidal state, and oceanographic habitat influence where they 
pursue prey (Hanson and Defran, 1993).

Harbor Porpoise

    In the Pacific, harbor porpoise are found in coastal and inland 
waters from Point Conception, California to Alaska and across to 
Kamchatka and Japan (Gaskin, 1984). Harbor porpoise appear to have more 
restricted movements along the western coast of the continental U.S. 
than along the eastern coast. 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 (Carretta et al., 2023; Stern et al., 2017). Harbor 
porpoises tend to occur in small groups and are considered to be 
relatively cryptic animals.
    Harbor porpoises are seen frequently outside the Bay and re-entered 
the Bay beginning in 2008 (Stern et al., 2017). They are now commonly 
seen year-round within the Bay in groups of two to five individuals, 
primarily on the west and northwest side of the Central Bay near the 
Golden Gate Bridge, near Marin County, and near the City of San 
Francisco (Duffy, 2015; Keener et al., 2012; Stern et al., 2017) in the 
vicinity of the Project Area. Harbor porpoises are generally shallow, 
short-duration divers and must forage nearly continuously to

[[Page 82842]]

meet their high metabolic needs (Wisniewska et al. 2016). Harbor 
porpoise movements into the Bay are likely influenced by prey 
availability (Duffy 2015; Stern et al., 2017).

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 4.

                  Table 4--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

    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 of Marine Mammals 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 of Marine Mammals 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 PG&E'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 (American National Standards Institute 
(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 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

[[Page 82843]]

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 
sound pressure levels (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 PG&E'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 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. 
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 PG&E'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., 2014), 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

[[Page 82844]]

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., 2014; Kastelein et al., 2015; 
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 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, 2021; Weilgart, 2007; Archer et al., 2010). Behavioral reactions 
can vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
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., Selye, 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

[[Page 82845]]

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 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, 2010; 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

    PG&E'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 feet (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

[[Page 82846]]

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 proposed action 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, 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-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-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 the 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 and/or TTS for individual marine 
mammals resulting from exposure to vibratory and impact pile driving. 
Based on the nature of the activity and the anticipated effectiveness 
of the mitigation measures (i.e., shutdown) discussed in detail below 
in the Proposed Mitigation

[[Page 82847]]

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 
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.
    PG&E's proposed activity includes 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). PG&E's 
proposed activity includes the use of impulsive (impact pile driving) 
and non-impulsive (vibratory pile driving) 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: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

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


[[Page 82848]]

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.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., pile driving and removal).
    The project includes vibratory pile installation and removal and 
impact pile driving. Source levels for these activities are based on 
reviews of measurements of the same or similar types and dimensions of 
piles available in the literature. Source levels for each pile size and 
activity are presented in table 6. Source levels for vibratory 
installation and removal of piles of the same diameter are 
conservatively assumed to be the same.
    The majority of source levels were selected from a single source, 
as shown in table 6 below. For the vibratory installation of 36-inch 
steel shell piles and vibratory installation of timber piles, NMFS 
determined it appropriate to use an average of source levels. NMFS 
reviewed all available monitoring reports of vibratory driving of 36-
inch steel piles in San Francisco Bay (Gast &Associated Environmental 
Consultants, 2021, 2023; Illingworth & Rodkin, 2018, 2020). Averaging 
of sound levels was performed by first converting from dB to linear 
units of pressure (Pascals [Pa]), averaging, and converting back to dB. 
The mean RMS level at 10m for San Francisco Bay was approximately 168 
dB re 1 Pa RMS. Therefore, NMFS has selected this average value as the 
most appropriate value for vibratory driving of 36-inch steel pipe 
piles during the proposed project. With regard to vibratory 
installation of timber piles, there are limited data available, and 
none from San Francisco Bay. Therefore, NMFS evaluated all available 
timber pile data (three projects from Puget Sound, WA, and one project 
from Norfolk, VA) (Greenbusch Group, 2018; Illingworth and Rodkin, 
2017; Laughlin, 2011; U.S. Navy, 2016) and calculated the mean and 
maximum RMS values for each project and for all projects together. The 
overall mean RMS value was approximately 158 dB re 1 Pa RMS. NMFS 
therefore selected this as an appropriate proxy value for vibratory 
driving of timber piles during the proposed project.

                          Table 6--Sound Source Levels for Pile Driving Activities \1\
----------------------------------------------------------------------------------------------------------------
                                                   Peak sound
          Pile type                 Method        pressure  (dB   RMS  (dB re 1   SEL  (dB re 1       Source
                                                  re 1 [mu]Pa)       [mu]Pa)      [mu]Pa2 sec)
----------------------------------------------------------------------------------------------------------------
                                          Hydroacoustic Data Collection
----------------------------------------------------------------------------------------------------------------
18-inch composite/plastic....  Impact Install..             185             160             150  Caltrans, 2020;
                                                                                                  extrapolated
                                                                                                  from 13-inch
                                                                                                  composite.
18 inch composite/plastic....  Vibratory                    N/A             152             N/A  WSDOT, 2012; 13-
                                Removal.                                                          inch composite
                                                                                                  used as proxy.
----------------------------------------------------------------------------------------------------------------
                                                Turbidity Curtain
----------------------------------------------------------------------------------------------------------------
Steel H-Pile.................  Vibratory                    N/A             143             N/A  Caltrans, 2020.
                                Install and
                                Removal.
Steel Shell Pile <=24 inches.  Vibratory                    N/A             153             N/A  Caltrans, 2020;
                                Install and                                                       24-inch pipe
                                Removal.                                                          pile used as
                                                                                                  proxy.
----------------------------------------------------------------------------------------------------------------
                                                 RWF Relocation
----------------------------------------------------------------------------------------------------------------
24 inch steel shell..........  Vibratory                    N/A             153             N/A  Caltrans, 2020.
                                Installation
                                and Removal.
24 inch steel shell..........  Impact                       208             193             178  Illingworth &
                                Installation                                                      Rodkin, Inc.
                                \2\.                                                              2014.
36 inch steel shell..........  Vibratory                    N/A             168             N/A  Gast &
                                Installation                                                      Associated
                                and Removal.                                                      Environmental
                                                                                                  Consultants,
                                                                                                  2021, 2023;
                                                                                                  Illingworth
                                                                                                  and Rodkin,
                                                                                                  2018, 2020.
                                                                                                  See
                                                                                                  explanation
                                                                                                  above.
----------------------------------------------------------------------------------------------------------------
                                               Slope Stabilization
----------------------------------------------------------------------------------------------------------------
14-16 inch Timber............  Vibratory.......             N/A             158             N/A  Greenbusch
                                                                                                  Group, 2018;
                                                                                                  Illingworth
                                                                                                  and Rodkin,
                                                                                                  2017;
                                                                                                  Laughlin,
                                                                                                  2011; U.S.
                                                                                                  Navy 2016. See
                                                                                                  explanation
                                                                                                  above.
14-16 inch Timber............  Impact..........             184             157             145  Caltrans, 2020.
14-16 in Composite...........  Vibratory.......             N/A             152             N/A  WSDOT, 2012. 13-
                                                                                                  inch composite
                                                                                                  used as proxy.
14-16 inch Composite.........  Impact..........             177             153             145  Caltrans, 2020.
----------------------------------------------------------------------------------------------------------------
\1\ All values are at 10 m from the source.
\2\ PG&E would use a bubble curtain attenuation system for impact pile driving of the RWF 24-inch steel shell
  piles, and we conservatively assumes a 5 dB reduction in source level from those presented here due to use of
  the attenuation system.


[[Page 82849]]

    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 all impact and vibratory installation and removal of 
piles with the exception of vibratory installation and removal of the 
36-inch steel pipe piles in the RWF Relocation. Illingworth & Rodkin 
conducted hydro-acoustic monitoring for the 2017 WETA Downtown San 
Francisco Ferry Terminal Expansion Project and calculated a TL 
coefficient of 18.7 for vibratory installation of 36-inch steel shell 
piles (Illingworth & Rodkin, 2018). Given the proximity to the project 
area, PG&E determined that 18.7 was an appropriate transmission 
coefficient to use for the vibratory installation of the 36-inch steel 
shell pile, and NMFS concurs.
    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 this 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, the optional User Spreadsheet 
tool predicts the distance at which, if a marine mammal remained at 
that distance for the duration of the activity, it would be expected to 
incur PTS. Source levels are provided above in table 6. Inputs used in 
the optional User Spreadsheet tool are provided below in table 7. 
Resulting estimated Level A and B harassment isopleths are provided in 
table 8.

                                        Table 7--User Spreadsheet Inputs
                                       [Source levels provided in Table 6]
----------------------------------------------------------------------------------------------------------------
               Pile type                           Method                    Duration              Piles/day
----------------------------------------------------------------------------------------------------------------
                                          Hydroacoustic Data Collection
----------------------------------------------------------------------------------------------------------------
18-inch composite/plastic..............  Impact Install...........  400 strikes/pile.........                 10
18 inch composite/plastic..............  Vibratory Removal........  20 minutes...............                 10
----------------------------------------------------------------------------------------------------------------
                                                Turbidity Curtain
----------------------------------------------------------------------------------------------------------------
Steel H-Pile...........................  Vibratory................  10 minutes...............                  4
Steel Shell Pile <=24 inches...........  Vibratory................  10 minutes...............                  4
----------------------------------------------------------------------------------------------------------------
                                                 RWF Relocation
----------------------------------------------------------------------------------------------------------------
24 inch steel shell....................  Vibratory................  10 minutes...............                  4
24 inch steel shell....................  Impact...................  400 strikes/pile.........                  4
36 inch steel shell....................  Vibratory................  20 minutes...............                  4
----------------------------------------------------------------------------------------------------------------
                                            Sediment Pin Installation
----------------------------------------------------------------------------------------------------------------
Timber.................................  Vibratory................  20 minutes...............                 20
Timber.................................  Impact...................  400 strikes/pile.........                 20
14-16 inch Composite...................  Vibratory................  20 minutes...............                 10
14-16 inch Composite...................  Impact...................  400 strikes/pile.........                 10
----------------------------------------------------------------------------------------------------------------


                           Table 8--Level A Harassment and Level B Harassment Isopleths From Vibratory and Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Level A/PTS isopleth  (m)
                                         --------------------------------------------------------------------------------
                                                                          Hearing groups                                                   Level B area
           Pile type & method            --------------------------------------------------------------------------------     Level B           of
                                                             Cetaceans                               Pinnipeds             isopleth  (m)  ensonification
                                         --------------------------------------------------------------------------------                     (km\2\)
                                                LF              MF              HF            Phocids        Otariids
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Hydroacoustic Data Collection Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
18-inch composite (Impact)..............              16              <1              19               9              <1              10           <0.01
18-inch Composite (Vibratory)...........               4              <1               6               3              <1           1,360            3.58
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Turbidity Curtain
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steel H-Pile (Vibratory)................              <1               0              <1              <1              <1             341            0.29

[[Page 82850]]

 
Steel Shell Pile <= 24 inches                          2              <1               4               2              <1           1,585            4.61
 (Vibratory)............................
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             RWF Temporary Relocation Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch Steel Shell Pile (Vibratory)....               2              <1               4               2              <1           1,585            4.54
24-inch Steel Shell Pile (Impact,                    294              11             351             158              12             736            1.06
 Attenuated)*...........................
36-inch Steel Shell Pile (Vibratory)....              20               3              28              14               2           3,688           23.46
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Sediment Pins
--------------------------------------------------------------------------------------------------------------------------------------------------------
14 to 16-inch Timber Pile (Vibratory)...              16               2              23              10               1           3,415           19.17
14 to 16-inch Timber Pile (Impact)......              12              <1              14               6              <1               6           <0.01
14 to 16-inch Composite Pile (Vibratory)               4              <1               6               3              <1           1,360             3.2
14 to 16-Inch Composite Pile (Impact)...               7              <1               9               4              <1             3.4           <0.01
--------------------------------------------------------------------------------------------------------------------------------------------------------
* 5 dB reduction in sound due to use of bubble curtain assumed.

Marine Mammal Occurrence

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations.
    Because reliable marine mammal density information is not available 
for the San Francisco Bay, several datasets were used to attain 
estimates of the abundance of marine mammals in the Bay. Datasets used 
included 5 years of sighting and stranding data from The Marine Mammal 
Center (TMMC) (NMFS, 2021a); 5 years of sighting and stranding data 
from the California Academy of Sciences (CAS) (NMFS, 2021b); citizen-
reported live sightings from iNaturalist.org; 5 days of sighting data 
during sediment investigation in 2020 during the initial phase of the 
project (Haase, 2021); and counts from haulouts. Data from all sources, 
when available, were considered. Depending on the distribution of 
sightings and granularity of data, different sources have been used to 
estimate the number of individuals of each species with the potential 
to occur in vicinity of the project. The largest ensonified area is 
during vibratory installation of 36-inch steel shell piles, which 
results in a 3,688 m isopleth and 23.46 km\2\ area of ensonification.

Harbor Seal

    Harbor seals in the Bay forage mainly within 7.0 mi (11.3 km) of 
their primary haulout site (Grigg et al. 2012), and often within just 
1-3 miles (1-5 km) (Torok, 1994). The only harbor seal haulout within 7 
miles (11.3 km) of the project site is YBI, which is 3.1 mi (5 km) to 
the east of the Project Area. Noise from the project is not expected to 
reach the haulout, however, harbor seals that use this haulout are 
likely to forage within ensonified areas from the project. Harbor seal 
take estimates were based on observations conducted by Marine Mammal 
Observers (MMOs) over a 5 day period in 2020, during sediment 
investigation in the initial phase of the project, within remedial 
response areas A, B, and C (See Haase, 2021). A maximum of 20 harbor 
seals were observed per day. PG&E therefore estimates 20 harbor seals 
per day within the project area per day. NMFS concurs with this 
assumption.

Northern Elephant Seal

    TMMC recorded 903 elephant seals in the Bay from 2016 to 2021 
(NMFS, 2021a). The CAS reported an additional 6 for a total of 909 over 
5 years in the Bay from 2016 to 2021 (NMFS, 2021b), yielding an average 
of 0.5 elephant seals per day. To ensure sufficient authorization of 
take of northern elephant seals, PG&E assumed 0.5 elephant seals will 
occur in the area per day (i.e., one elephant seal every 2 days). NMFS 
concurs with this assumption.

California Sea Lion

    The Pier 39 K-Dock haulout is the only regularly used California 
Sea Lion haulout in the vicinity of the Project Area, adjacent to Area 
C. The Sea Lion Center at Pier 39 regularly counted the sea lions at K-
Dock from 1991 through 2018. From 2016 through 2018, the yearly average 
ranged from 89 to 229 animals per day. The average per day over all 3 
years was 191 sea lions (Pacific Gas & Electric, 2023). Although there 
are times of the year when the K-dock is unoccupied or there are few 
individuals present, it is difficult to predict abundance based on time 
of year. In order to ensure sufficient authorization of sea lions, PG&E 
is assuming a local abundance estimate of 191 sea lions per day within 
the estimated harassment area, and NMFS concurs.

Northern Fur Seal

    TMMC recorded 44 northern fur seals in the Bay from 2016 to 2021 
(NMFS, 2021a). CAS recorded an additional 3 for a total of 47 over 5 
years (NMFS, 2021b), yielding 0.03 per day, or approximately 10 per 
year. In the fall and winter, northern fur seals occasionally strand on 
YBI and Treasure Island (Pacific Gas & Electric, 2023), approximately 
2.0 mi (3.2 km) from the project area. Using PG&E's assumption of 
approximately 0.03 fur seals per day over the course of 50 days of pile 
driving plus known fur seal strandings near the project area, NMFS has 
determined it appropriate to assume five fur seals in the project area 
during the project time period.

Steller Sea Lion

    Steller sea lions are rare in San Francisco Bay. TMMC recorded four 
Steller sea lions in the Bay from 2016 to 2021 (NMFS, 2021a), while CAS 
reported no Steller sea lions during this time (NMFS, 2021b). In 2020 
and 2021, INaturalist.org recorded four Steller sea lions in the Bay. 
On rare occasions, Steller sea lions are seen on the Pier 39 K-dock 
haulout. An adult male was spotted there in May 2023 (Segura, 2023) and 
in previous years a single

[[Page 82851]]

male Steller sea lion had been observed using the Pier 39 K-dock 
haulout intermittently during July and August and occasionally 
September (Pacific Gas & Electric, 2023). Given these known occasional 
occurrences of the Steller sea lion at Pier 39, PG&E feels it is 
appropriate to assume five Steller sea lions in the project area during 
the time period of the project, and NMFS concurs.

Bottlenose Dolphins

    Historically, observations of bottlenose dolphins have occurred 
west of Treasure Island and were concentrated in the Project vicinity 
along the nearshore area of San Francisco south to Redwood City. Since 
2016, one individual has been regularly seen near the former Alameda 
Air Station and five animals were regularly seen in the summer and fall 
of 2018 in the same location (Pacific Gas & Electric, 2023). A recent 
study reports that dolphins have been sighted in the vicinity of the 
Golden Gate Bridge, around Yerba Buena and Angel Islands, and in the 
central Bay (Keener et al., 2023). PG&E is assuming that one group of 
bottlenose dolphins will enter into the project isopleth per month of 
pile driving, and NMFS concurs. A group size is estimated to be five 
animals based on sightings of bottlenose dolphins in the Bay (Pacific 
Gas & Electric, 2023).

Harbor Porpoise

    Harbor porpoises are primarily seen near the Golden Gate Bridge, 
Marin County, and the city of San Francisco on the northwest side of 
the Bay (Keener et al., 2012; Stern et al., 2017), in the vicinity of 
the project area. Limited data exists on the abundance of harbor 
porpoises in the Bay, and therefore data from MMOs in 2020 was used 
(see Haase 2021). An individual harbor porpoise was seen in the project 
zone on 2 of the 5 days, and a group of two individuals was reported on 
a separate day of the 5 day observation period (Haase, 2021). To ensure 
sufficient authorization of take of harbor porpoise, it is estimated 
that two harbor porpoises will occur within the estimated harassment 
area per day.

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, northern 
elephant seals, and harbor porpoises, NMFS multiplied the daily 
occurrence estimates described in the Marine Mammal Occurrence section 
by the number of project days (table 9).
    For northern fur seals, PG&E is assuming a total of five animals in 
the area of the project during the duration of the project, based on 
sightings in the Bay and known strandings on YBI (see Marine Mammal 
Occurrence above), and is therefore requesting, and NMFS is proposing 
to authorize, take of five northern fur seals by Level B harassment 
(table 9).
    Although Steller sea lions are rare in San Francisco Bay, based on 
sighting data and known occurrence of Steller sea lions on the Pier 39 
K-dock haulout (PG&E, 2023; Segura, 2023), PG&E is conservatively 
requesting five takes by Level B harassment of Steller sea lions during 
the time period of the project, and NMFS concurs (table 9).
    For bottlenose dolphins, PG&E estimates that one group of five 
bottlenose dolphins may be taken by Level B harassment per month of 
pile driving. Based on 5 months of pile driving, NMFS proposes to 
authorize 25 takes by Level B harassment of bottlenose dolphins.

              Table9--Estimated Take by Level B Harassment Proposed for Authorization and Estimated Take as a Percentage of the Population
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Estimated Level B
                Species                             Stock                Expected occurrence            take        Stock abundance *   Percent of stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pacific Harbor Seal....................  California................  20 seals per day..........               1000             30,968                3.2
Northern Elephant Seal.................  California Breeding.......  0.5 seals per day.........                 25            187,386               0.01
California Sea Lion....................  United States.............  191 sea lions per day.....              9,550            257,606                3.7
Northern Fur Seal......................  California; Eastern North   5 seals over project                        5    14,050; 626,618        0.04; 0.001
                                          Pacific.                    duration.
Steller sea lion.......................  Eastern United States.....  5 sea lions over project                    5             43,201               0.01
                                                                      duration.
Bottlenose dolphin.....................  Coastal California........  5 dolphins per month of                    25                453                5.5
                                                                      project.
Harbor Porpoise........................  San Francisco-Russian       2 porpoises per day.......                100              7,777                1.3
                                          River.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports reports.

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 will be effective if implemented 
(probability of accomplishing the mitigating result if

[[Page 82852]]

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.
    PG&E must follow mitigation measures as specified below.
    PG&E must ensure that construction supervisors and crews, the 
monitoring team, and relevant PG&E 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

    PG&E must establish shutdown zones and Level B monitoring 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 animal (or in anticipation of an animal 
entering the defined area). Shutdown zones are based on the largest 
Level A harassment zone for each pile size/type and driving method, and 
behavioral monitoring zones are meant to encompass Level B harassment 
zones for each pile size/type and driving method, as shown in table 8. 
A minimum shutdown zone of 10 m would be required for all in-water 
construction activities to avoid physical interaction with marine 
mammals, and the radii of the shutdown zones are rounded to the next 
largest 10 m interval in comparison to the Level zone for each activity 
type. Marine mammal monitoring will be conducted during all pile 
driving activities to ensure that marine mammals do not enter Level A 
shutdown zones, that marine mammal presence in the isopleth does not 
exceed authorized take, and to prevent take of the humpback and gray 
whale. Proposed shutdown zones for each activity type are shown in 
table 10.
    Prior to pile driving, shutdown zones and monitoring zones will be 
established based on zones represented in table 10. Observers will 
survey the shutdown zones for at least 30 minutes before pile driving 
activities start. If marine mammals are found within the shutdown zone, 
pile driving will be delayed until the animal has moved out of the 
shutdown zone, either verified by an observer or by waiting until 15 
minutes has elapsed without a sighting. If a marine mammal approaches 
or enters the shutdown zone during pile driving, the activity will be 
halted. Pile driving may resume after the animal has moved out of and 
is moving away from the shutdown zone or after at least 15 minutes has 
passed since the last observation of the animal.
    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.
    If a species for which authorization has not been granted (i.e., 
gray whale or humpback whale), or a species which has been granted but 
the authorized takes are met, is observed approaching or within the 
Level B monitoring zone, pile driving activities will be shutdown 
immediately. Activities will not resume until the animal has been 
confirmed to have left the area or 15 minutes has elapsed with no 
sighting of the animal.

    Table 10--Shutdown Zones and Level B Monitoring Zones by Activity
------------------------------------------------------------------------
                                    Shutdown zone for   Monitoring zone
       Pile type and method          all species (m)          (m)
------------------------------------------------------------------------
Hydroacoustic Data Collection
 Piles:
    18-inch Composite/Plastic                      20                 10
     (impact).....................
    18-Inch Composite/Plastic                      10              1,360
     (vibratory removal)..........
Turbidity Curtain:
    Steel H-Pile (Vibratory                        10                341
     Install and Removal).........
    24-inch steel shell pile                       10              1,585
     (Vibratory install and
     removal).....................
RWF Relocation Piles:
    24-inch steel shell pile                       10              1,585
     (Vibratory install and
     removal).....................
    24-inch steel shell pile                      360                736
     (impact-attenuated)..........
    36-inch steel shell pile                       30              3,688
     (vibratory)..................
Sediment Pins:
    14-16 inch timber (Vibratory).                 30              3,415
    14-16 inch timber (impact)....                 20                 10
    14-16 inch composite (impact).                 10                 10
    14-16 inch composite                           20              1,360
     (vibratory install)..........
------------------------------------------------------------------------

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 as much of the Level 
B harassment zones as possible. 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

[[Page 82853]]

the zone for a 30-minute period. If a marine mammal is observed within 
the shutdown zones, 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 are used to provide additional protection to 
marine mammals by providing warning and/or giving marine mammals a 
chance to leave the area prior to the hammer operating at full 
capacity. 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 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 steel piles less than 24 inches in diameter to 
interrupt the acoustic pressure and reduce impact on marine mammals. 
Impact pile driving will not be allowed for 36-inch steel shell piles. 
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 will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present 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 and the 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 education (degree in biological 
science or related field) or training for experience.
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator would be designated. The lead 
observer would be required to have prior experience working as a marine 
mammal observer during construction.
     PSOs will submit PSO resumes for approval by NMFS 30 days 
prior to the onset of pile driving.
     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.
    PG&E would have between one and three PSOs on site at all times 
during pile driving activities. One PSO would be designated as the Lead 
PSO and would receive updates from other PSOs. The Lead PSO would be 
stationed at the active pile driving rig or at the best vantage point 
practicable to monitor the shutdown zones and implement shutdown and 
delay procedures. The other PSOs would be stationed at the best vantage 
points practicable to observe the monitoring zones. Exact locations 
would be determined in the field based on the pile driving site, field 
conditions, and in coordination with contractors, but may include 
docks,

[[Page 82854]]

barges, and tower structures. PSOs would be equipped with high quality 
binoculars or spotting scopes for monitoring and radios and cell phones 
for maintaining contact with other observers and work crew. Monitoring 
would be conducted 30 minutes before, during, and 30 minutes after all 
in-water construction activities. 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.

Data Collection

    PSOs would use approved data forms to record the following 
information:

     Dates and times (beginning and end) of all marine mammal 
monitoring.
     PSO locations during marine mammal monitoring.
     Construction activities occurring during each daily 
observation period, including how many and what type of piles were 
driven or removed and by what method (i.e., impact or vibratory).
     Weather parameters and water conditions.
     The number of marine mammals observed, by species, 
relative to the pile location and if pile driving or removal was 
occurring at time of sighting.
     Distance and bearings of each marine mammal observed to 
the pile being driven or removed.
     Description of marine mammal behavior patterns, including 
direction of travel.
     Age and sex class, if possible, of all marine mammals 
observed.
     Detailed information about implementation of any 
mitigation triggered (such as shutdowns and delays), a description of 
specific actions that ensued, and resulting behavior of the animal if 
any.

Reporting

    PG&E 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 (beginning and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period including: (a) the number and types of piles driven 
and the method; and (b) total duration of driving time for each pile 
(vibratory driving) and number of strikes for each pile (impact 
driving).
     PSO locations during marine mammal monitoring;
     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 must 
be recorded: (a) Name of PSO who sighted the animal(s) and PSO location 
and activity at time of sighting; (b) time of sighting; (c) 
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; (d) 
distance and location of each observed marine mammal relative to pile 
being driven or removed for each sighting; (e) estimated number of 
animals (min/max/best estimate); (f) estimated number of animals by 
cohort (adults, juveniles, neonates, group composition, etc.); (g) 
animal's closest point of approach and estimated time spent within the 
harassment zone; (h) 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);
     Number of marine mammals detected within the harassment 
zones, by species; and
     Detailed information about implementation of any 
mitigation (e.g., shutdowns and delays), a description of specific 
actions that ensued, and resulting changes in behavior of the 
animal(s), if any.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, PG&E 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, PG&E 
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. PG&E would not resume their activities until notified by 
NMFS. The report would include the following:
     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

[[Page 82855]]

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 3, 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 would be due to potential 
behavioral disturbances. The potential for harassment is minimized 
through construction methods and the implementation of planned 
mitigation strategies (see Proposed Mitigation section).
    Behavioral responses of marine mammals to pile driving at the 
project site, if any, are expected to be mild and temporary. Marine 
mammals within the Level B harassment zone may not show any visual cues 
they are disturbed by activities or could become alert, avoid the area, 
leave the area, or display other mild responses that are not observable 
such as changes in vocalization patterns. Given the short duration of 
noise-generating activities per day and that pile driving and removal 
would occur over approximately 50 days during a span of 5 months, any 
harassment would be temporary. There are no other areas or times of 
known biological importance for any of the affected species.
    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 incidental take authorization are 
listed as threatened or endangered under the ESA. Only one stock, the 
Eastern North Pacific Stock of the northern fur seal, is listed as 
depleted under the MMPA. However, we do not expect the proposed 
authorizations in this action to affect the stock. No injury or 
mortality is proposed for authorization, take by Level B harassment is 
limited (five takes over the duration of the project), and the proposed 
action should have no effect on the reproduction of this species. In 
addition, the five authorized takes for the northern fur seal include 
both the depleted Eastern North Pacific Stock and the California stock, 
which is not depleted.
    The relatively low marine mammal occurrences in the area, 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.
    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.
    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 
or marine mammal habitat; and
     The presumed efficacy of the mitigation measures in 
reducing the effects of the specified activity.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted 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 stocks (See table 9). These are all 
likely conservative estimates because they assume all takes are of 
different individual animals which is likely not the case. 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.

[[Page 82856]]

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 Pacific Gas & Electric for conducting pile driving 
activities in San Francisco Bay from April 1, 2024 to March 31, 2025, 
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 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity 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 1 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: November 20, 2023.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2023-26012 Filed 11-24-23; 8:45 am]
BILLING CODE 3510-22-P