Notice2025-23798
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Pacific Gas & Electric Sediment Remediation Project, Remedial Response Area C, San Francisco Bay
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
December 29, 2025
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from Pacific Gas & Electric (PG&E) for authorization to take marine mammals incidental to construction for a sediment remediation project in San Francisco Bay, CA. 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, 1-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.
Full Text
<html>
<head>
<title>Federal Register, Volume 90 Issue 245 (Monday, December 29, 2025)</title>
</head>
<body><pre>
[Federal Register Volume 90, Number 245 (Monday, December 29, 2025)]
[Notices]
[Pages 60635-60650]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-23798]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XF272]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Pacific Gas & Electric Sediment
Remediation Project, Remedial Response Area C, 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.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from Pacific Gas & Electric (PG&E)
for authorization to take marine mammals incidental to construction for
a sediment remediation project in San Francisco Bay, CA. 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, 1-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 January
28, 2026.
ADDRESSES: Comments should be addressed to Permits and Conservation
Division, Office of Protected Resources, National Marine Fisheries
Service, and should be submitted via email to <a href="/cdn-cgi/l/email-protection#135a47433d7972707c716660537d7c72723d747c65"><span class="__cf_email__" data-cfemail="044d50542a6e65676b667177446a6b65652a636b72">[email protected]</span></a>.
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. In
case of problems accessing these documents, please call the contact
listed below.
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 <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Kristy Jacobus, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Section 101(a)(5) (D) of the MMPA (16 U.S.C. 1361 et seq.)
directs 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 (collectively referred to as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms used above are included in the relevant sections below
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS
regulations at 50 CFR 216.103.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and
[[Page 60636]]
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
NAO 216-6A, which do not individually or cumulatively have the
potential for significant impacts on the quality of the human
environment and for which we have not identified any extraordinary
circumstances that would preclude this categorical exclusion.
Accordingly, NMFS has preliminarily determined that the issuance of the
proposed IHA qualifies to be categorically excluded from further NEPA
review.
Summary of Request
On May 4, 2023, NMFS received an application from PG&E requesting
the take of marine mammals incidental to construction of a Sediment
Remediation Project in Remedial Response Areas A and B, Piers 39 to
43\1/2\, San Francisco Bay. NMFS published a notice of a proposed IHA
and request for comments in the Federal Register on December 27, 2023
(88 FR 82836). We subsequently published the final notice of our
issuance of the IHA on January 30, 2024 (89 FR 5865), making the IHA
valid from May 1, 2024 through April 30, 2025. Following a request from
PG&E, NMFS published a notice of proposed renewal IHA on October 16,
2024 (89 FR 83459) and issued the renewal IHA on November 22, 2024 (89
FR 92649), making the renewal IHA valid from May 1, 2025 to April 30,
2026. The specified activities were expected to result in the take of
seven species of marine mammal including the bottlenose dolphin
(Tursiops truncates), harbor porpoise (Phocoena phocoena), California
sea lion (Zalophus californianus), northern fur seal (Callorhinus
ursinus), Steller sea lion (Eumetopias jubatus), harbor seal (Phoca
vitulina), and northern elephant seal (Mirounga angustirostris).
On August 11, 2025, NMFS received a request from PG&E for an IHA to
take marine mammals incidental to construction in Remedial Response
Area C, Pier 41\1/2\, San Francisco Bay, as a part of a continuation of
the Sediment Remediation Project. Following NMFS' review of the
application, PG&E submitted a revised version on December 18, 2025,
which was deemed adequate and complete. PG&E's request is for take of
eight species (nine stocks) 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. NMFS previously issued
an IHA and renewal IHA to PG&E (herein referred to as the 2024 IHA and
2025 renewal IHA) (89 FR 5865, January 30, 2024; 89 FR 92649, November
24, 2024) to incidentally take marine mammals, by Level B harassment,
for similar construction activities in San Francisco Bay, as part of
the larger sediment remediation project. Although PG&E is proposing to
install many of the same pile types as the 2024 IHA, some pile types
differ. In addition, some source levels and harassment distances have
been adjusted based on hydroacoustic measurements conducted by PG&E.
PG&E is also requesting take of gray whale (Eschrichtius robustus)
based on recent marine mammal monitoring in San Francisco Bay. The
proposed mitigation, monitoring, and reporting measures remain the same
as prescribed in the 2024 IHA with slight modifications (e.g., shut
down zones distance changes) as described below.
PG&E complied with all the requirements (e.g., mitigation,
monitoring, and reporting) of the previous IHA, and information
regarding their monitoring results may be found in the Estimated Take
of Marine Mammals section.
This proposed IHA would cover 1 year of a larger project for which
PG&E obtained prior IHAs and intends to request take authorization for
subsequent facets of the project. The larger 5-7 year project involves
construction to remediate contaminated sediment.
Description of Proposed Activity
Overview
PG&E is proposing to conduct pile driving to remediate sediments
impacted by polycyclic aromatic hydrocarbons (PAHs) around the area
offshore and under Pier 41\1/2\ in San Francisco Bay, CA. PG&E would
install piles for a turbidity curtain, the temporary relocation of the
Blue and Gold Fleet (BGF), and sediment pins for slope stabilization.
PG&E plans to use primarily vibratory pile driving. Impact pile driving
would only be used as needed to seat piles. Vibratory and impact pile
driving would introduce underwater sounds that may result in take, by
Level B harassment, of marine mammals. Level A harassment of marine
mammals is not expected, and none is proposed for authorization.
Dates and Duration
The proposed IHA would be valid for the statutory maximum of 1 year
from the date of effectiveness. It will become effective upon written
notification from the applicant to NMFS, but not beginning later than 1
year from the date of issuance or extending beyond 2 years from the
date of issuance. In-water construction is anticipated to occur over 62
construction days between March and November. However, project delays
may occur due to a number of factors, including availability of
equipment and/or materials, weather-related delays, equipment
maintenance and/or repair, and other contingencies. Pile driving will
occur during daylight hours. Any impact pile driving would occur from
June 1 to November 30 to protect sensitive life stages of Endangered
Species Act (ESA)-listed fish species in the area.
Specific Geographic Region
PG&E's proposed construction activities would occur in San
Francisco Bay, CA, about 3.7 miles (mi) (6 kilometers [km]) from the
entrance. PG&E's sediment remediation 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. All pile driving during the timeframe of this
proposed IHA would be in Remedial Response Area C, which is the Pier
41\1/2\ offshore area and the area under Pier 41\1/2\. See figure 1.
[[Page 60637]]
[GRAPHIC] [TIFF OMITTED] TN29DE25.000
Figure 1--Project Location
Detailed Description of the Specified Activity
PG&E proposes to conduct construction in San Francisco Bay to
remediate sediments impacted with PAHs. Construction components include
installation of piles to attach a turbidity curtain; installation of
sediment pins to promote slope stability; removal and installation of
piles to relocate the Blue and Gold Fleet (BGF); removal of impacted
sediment using mechanical dredges; and capping and armoring of sediment
left in place.
Underwater noise generated by dredging, capping, and armoring are
within range of other background noise in San Francisco Bay and are not
anticipated to result in take of marine mammals.
Pile driving to install and remove piles is expected to result in
take of marine mammals and these activities are described below in
detail.
Turbidity curtain--Because increased water turbidity might occur
during dredging and capping activities, a turbidity curtain would be
installed across the full depth of the water column extending to the
sediment surface. The turbidity curtain would be attached to 20
temporary steel shell piles less than 12 inches (30.5 centimeters [cm])
in diameter. The piles would be installed with primarily vibratory
methods. Impact pile driving would be used as needed to seat the piles.
The piles would be removed using vibratory methods.
Slope stabilization--In order to prevent rotational or sliding
failure in dredged and capped areas, approximately 500 18-inch (45.7-
cm) diameter tapered timber piles (referred to as sediment pins) would
be installed using vibratory and impact hammers.
BGF Relocation--Relocation of the BGF would require removal of
piles and overwater structures at the current location and
reinstallation after remediation actions are complete. Eight 24-inch
(61-cm) steel shell piles, two 42-inch (106.7-cm) steel shell piles,
and five 30-inch (76.2-cm) steel shell piles would be removed using
vibratory methods. These piles would then be replaced by eight 30-inch
(76.2-cm) steel shell piles, five 36-inch (91.4-cm) steel shell piles,
four 24-inch (61-cm) steel shell piles, and four 36-inch (91.4-cm)
[[Page 60638]]
steel shell piles. These piles would all be installed using primarily
vibratory methods. An impact hammer would be used only to seat the
piles to the required tip elevation.
Table 1--Overview of Piles for Installation and Removal
------------------------------------------------------------------------
Total number of
Pile size and type Hammer type piles
------------------------------------------------------------------------
Turbidity Curtain
------------------------------------------------------------------------
Steel shell piles <12 inches Vibratory and 40 (20 installed,
(30.5 cm). impact. 20 removed).
------------------------------------------------------------------------
Slope Stabilization
------------------------------------------------------------------------
18-inch (45.7-cm) tapered timber Vibratory and 500.
impact.
------------------------------------------------------------------------
BGF Relocation
------------------------------------------------------------------------
24-inch (61-cm) steel shell Vibratory removal. 8.
piles.
Vibratory and 4.
impact
installation.
30-inch (76.2 cm) steel shell Vibratory removal. 5.
piles.
Vibratory and 8.
impact
installation.
36-inch (91.4-cm) steel shell Vibratory and 9.
piles. impact
installation.
42-inch steel shell piles....... Vibratory removal. 2.
------------------------------------------------------------------------
Table 2--Estimated Days of Pile Driving
----------------------------------------------------------------------------------------------------------------
Number of
piles
Activity Total number of piles installed/ Days of pile
removed per driving
day
----------------------------------------------------------------------------------------------------------------
Turbidity Curtain............................. 40 (20 installed, 20 removed)... 4 10
Slope stabilization........................... 500............................. 15 * 34
BGF Temporary Relocation...................... 25 (<36 inches [91.4 cm]) (13 4 * 6
removed, 12 installed).
................................
11 (>=36 inches [91.4 cm])...... 2 * 6
-----------------------------------------------------------------
Total..................................... ................................ .............. 56
Total +10% buffer......................... ................................ .............. * 62
----------------------------------------------------------------------------------------------------------------
* Rounded to the nearest whole number.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting sections).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
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 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 (M/SI) 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 (including from
the draft 2024 SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
[[Page 60639]]
Table 3--Species \1\ With Estimated Take From the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
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\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray whale...................... Eschrichtius robustus.. Eastern North Pacific.. -,-,N 26,960 (0.05, 25,849, 801 131
2016).
Family Delphinidae:
Bottlenose Dolphin.............. Tursiops truncatus..... California Coastal..... -,-,N 453 (0.06, 346, 2011). 2.7 >=2
Harbor porpoise................. Phocoena phocoena...... San Francisco/Russian -,-,N 7,777 (0.62, 4,811, 73 >=0.4
River. 2017).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
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.... Eastern Pacific........ -, D,Y 626,618 (0.2, 530,376, 11,403 373
2019).
Northern fur seal............... Callorhinus ursinus.... California............. -,-,N 14,050 (N/A, 7,524, 451 1.8
2013).
Steller sea lion................ Eumetopias jubatus..... Eastern................ -,-,N 36,308 (N/A, 36,308, 2,178 93.2
2022).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... California............. -,-,N 30,968 (N/A, 27,348, 1,641 43
2012).
Northern elephant seal.......... Mirounga angustirostris California breeding.... -, -, N 187,386 (N/A, 85,369, 5,122 13.7
2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies</a>).
\2\ 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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>. 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, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
As indicated above, all eight species (with nine managed stocks) in
table 3 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. While the humpback
whale occasionally enters San Francisco Bay, if this species is to
approach the Level B harassment zone, construction will be shutdown.
Therefore, no take is expected of humpback whale and the species will
not be discussed further.
With the exception of the gray whale, a description of all marine
mammals proposed for take in this IHA can be found in the notice of the
proposed 2024 IHA (88 FR 82836, November 11, 2023), and the information
remains applicable to this proposed IHA as well. NMFS has reviewed
recent draft Stock Assessment Reports, information on relevant Unusual
Mortality Events, and recent scientific literature, and determined that
no new information affects our original analysis of impacts to these
species under this proposed IHA.
For the 2024 IHA, no take was authorized for gray whales, and PG&E
shut down if gray whales approached the estimated Level B harassment
isopleth. During construction conducted under the 2024 IHA, gray whales
were present in San Francisco Bay more than expected, resulting in
multiple instances of shutdown. Therefore, PG&E is requesting take for
small numbers of gray whales by Level B harassment in this IHA. Gray
whales will be discussed below.
Gray Whale
During the summer and fall most Eastern North Pacific gray whales
feed in the Chukchi, Beaufort, and northwestern Bering Seas, with a
small number that summer and feed along the Pacific coast between
Kodiak Island, Alaska and northern California. The southward migration
generally occurs from December through February and peaks in January,
and the northward migration generally occurs from February through May
and peaks in March (NOAA National Centers for Coastal Ocean Science,
2007). Although their presence in San Francisco Bay is generally
considered uncommon, increased numbers of gray whales have been seen in
San Francisco Bay in recent years, and gray whales were observed in San
Francisco Bay more often than expected during PG&E's construction under
the 2024 IHA (Integral Consulting Inc., 2025a).
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., Au and Hastings, 2008; Richardson et al.,
1995; Wartzok and Ketten, 1999). 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.). Generalized hearing ranges were
chosen based on the ~65 decibel (dB) threshold from composite
audiograms, previous analyses in NMFS (2018), and/or data from Southall
et al. (2007, 2019). We note that the names of two hearing groups and
the generalized hearing ranges of all marine mammal hearing groups have
been recently updated (NMFS, 2024) as reflected below in table 4.
[[Page 60640]]
Table 4--Marine Mammal Hearing Groups (NMFS, 2024)
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz.
whales).
High-frequency (HF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
Very High-frequency (VHF) cetaceans (true 200 Hz to 165 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger &
L. australis).
Phocid pinnipeds (PW) (underwater) (true 40 Hz to 90 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 68 kHz.
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 may not be as broad. Generalized hearing range
chosen based on approximately 65 dB threshold from composite
audiogram, previous analysis in NMFS (2018), and/or data from Southall
et al. (2007, 2019). Additionally, animals are able to detect very
loud sounds above and below that ``generalized'' hearing range.
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
A description of the potential effects of the specified activities
on marine mammals and their habitat may be found in the notice of the
proposed 2024 IHA (88 FR 82836, November 27, 2023).
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 NMFS'
consideration of ``small numbers,'' the negligible impact
determinations, and impacts on subsistence uses.
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 behavioral reactions and/or temporary threshold shift (TTS) for
individual marine mammals resulting from exposure to pile driving.
Based on the nature of the activity and the anticipated effectiveness
of the mitigation measures (i.e., shutdown at the Level A harassment
isopleth) discussed in detail below in the Proposed Mitigation section,
Level A harassment is neither anticipated nor proposed to be
authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes there is
some reasonable potential for marine mammals to be behaviorally
harassed or incur some degree of auditory injury (AUD INJ); (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 Criteria
NMFS recommends the use of acoustic criteria 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 AUD INJ 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 construction 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' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to
assess AUD INJ (Level A harassment) to five different underwater marine
mammal
[[Page 60641]]
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 construction includes the use of impulsive (impact pile
driving) and non-impulsive (vibratory pile driving) sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. The
thresholds are provided in the table below. The references, analysis,
and methodology used in the development of the criteria are described
in NMFS' 2024 Updated Technical Guidance, which may be accessed at:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>.
Table 5--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9; Lpk,flat: 230 dB; Cell 10: LE,OW,24h: 199 dB.
LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [micro]Pa\2\s. In this table, criteria are abbreviated to be
more reflective of International Organization for Standardization standards (ISO, 2017). The subscript
``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within the
generalized hearing range of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated with
cumulative sound exposure level criteria indicates the designated marine mammal auditory weighting function
(LF, HF, and VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours.
The weighted cumulative sound exposure level criteria 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 criteria will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
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 installation. Source levels for these activities are based
on hydroacoustic monitoring conducted under the 2024 IHA (Reyff and
Ambaskar, 2025) and 2025 renewal IHA (Illingworth & Rodkin, 2025) and
on reviews of measurements of the same or similar types and dimensions
of piles available in the literature. Source levels for each pile size
are presented in table 6. Source levels for vibratory installation and
removal of piles of the same diameter are assumed to be the same. PG&E
plans to use a bubble curtain for all impact pile driving, and a 5 dB
reduction in source level is assumed from those presented in table 6
for impact pile driving due to the use of a bubble curtain.
Table 6--Sound Source Levels for Pile Driving
----------------------------------------------------------------------------------------------------------------
Source level (at 10 meters [m])
----------------------------------------------------
Pile Hammer Peak sound Source
pressure (dB RMS (dB re 1 SEL (dB re 1
re 1 [mu]Pa) [mu]Pa) [mu]Pa2 sec)
----------------------------------------------------------------------------------------------------------------
Turbidity Curtain
----------------------------------------------------------------------------------------------------------------
Steel shell piles <12 inches Vibratory.... N/A 157.3 N/A Illingworth &
(30.5 cm). Rodkin (2025).
Steel shell piles <12 inches Impact *..... 192 177 167 Caltrans (2015,
(30.5 cm). 2020).
----------------------------------------------------------------------------------------------------------------
Slope Stabilization
----------------------------------------------------------------------------------------------------------------
18-inch (45.7-cm) tapered Vibratory.... N/A 158 N/A Greenbusch
timber. Group (2018),
Illingworth &
Rodkin (2017),
Laughlin,
(2011), U.S.
Navy (2016).
Impact *..... 184 157 145 Caltrans
(2020).
----------------------------------------------------------------------------------------------------------------
BGF Relocation
----------------------------------------------------------------------------------------------------------------
24-inch (61-cm) steel shell. Vibratory.... N/A 160.4 N/A Reyff and
Ambaskar
(2025).
Impact *..... 208 193 178 Illingworth &
Rodkin (2014).
30-inch (76.2-cm) steel Vibratory.... N/A 171.8 N/A Reyff and
shell. Ambaskar
(2025).
Impact *..... 210 190 177 Caltrans
(2015).
36-inch (91.4-cm) steel Vibratory.... N/A 169.4 N/A Reyff and
shell. Ambaskar
(2025).
Impact *..... 210 193 183 Caltrans,
(2015, 2020).
42-inch (106.7-cm) steel Vibratory.... N/A 170 N/A NMFS 2025
shell. analysis.
----------------------------------------------------------------------------------------------------------------
* PG&E would use a bubble curtain attenuation system for all impact pile, and NMFS assumes a 5 dB reduction in
source level from those presented here due to use of the attenuation system.
[[Page 60642]]
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 (R<INF>1</INF>/R<INF>2</INF>),
Where:
TL = transmission loss in dB;
B = transmission loss coefficient;
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile; and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement.
Absent site-specific data, 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 of
piles without site-specific acoustical monitoring (i.e., impact
installation of 12-, 24- 30-, and 36-inch [30.5-, 61-, 76.2-, and 91.4-
cm] steel shell piles, vibratory and impact installation of 18-inch
[45.7-cm] tapered timber piles, and vibratory installation of 42-inch
[106.7-cm] steel shell piles).
As described above, PG&E conducted hydroacoustic monitoring for the
vibratory installation of 12-, 24-, 30-, and 36-inch (61-, 76.2-, and
91.4-cm) steel shell piles, and the TL coefficients were 22, 24.9,
22.5, and 23.9, respectively (Reyff and Ambaskar, 2025, Illingworth &
Rodkin, 2025). PG&E proposes to use these site specific TL coefficients
for the respective piles, 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 2024 Updated 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 AUD INJ. Inputs used in the NMFS User Spreadsheet are provided in
table 7. Level A and Level B harassment isopleths are provided in table
8.
Table 7--NMFS User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Weighting
Piles per Strikes Duration to TL factor
Pile size/type Hammer type day per pile drive pile coefficient adjustment
(min) (WFA)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Turbidity Curtain
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steel shell piles <12 inches (30.5 cm)......... Vibratory............................. 4 N/A 20 22 2.5
Impact................................ 4 25 N/A 15 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Slope Stabilization
--------------------------------------------------------------------------------------------------------------------------------------------------------
18-inch (45.7-cm) tapered timber............... Vibratory............................. 15 N/A 20 15 2.5
Impact................................ 15 400 N/A 15 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
BGF Relocation
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch (61-cm) steel shell.................... Vibratory............................. 4 N/A 20 24.9 2.5
Impact................................ 4 25 N/A 15 2
30-inch (76.2-cm) steel shell.................. Vibratory............................. 4 N/A 20 22.5 2.5
Impact................................ 4 25 N/A 15 2
36-inch (91.4 cm) steel shell.................. Vibratory............................. 2 N/A 20 23.9 2.5
Impact................................ 2 50 N/A 15 2
42-inch (106.7-cm) steel shell................. Vibratory............................. 2 N/A 20 15 2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 8--Level A and Level B Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
Level A harassment isopleth (m) Level B
------------------------------------------------------------ harassment
Pile isopleth
LF HF VHF Phocids Otariid (m)
----------------------------------------------------------------------------------------------------------------
Turbidity Curtain
----------------------------------------------------------------------------------------------------------------
Steel shell pile <12 inch (30.5 cm) 7 4 6 9 4 496
(vibratory)...........................
Steel shell pile <12 inch (30.5 cm) 10 1 13 8 3 63
(impact, attenuated) *................
----------------------------------------------------------------------------------------------------------------
Slope Stabilization
----------------------------------------------------------------------------------------------------------------
18-inch (45.7-cm) tapered timber 17 7 14 22 7 3,415
(vibratory)...........................
18-inch (45.7-cm) tapered timber 5 1 7 4 2 3
(impact, attenuated) *................
----------------------------------------------------------------------------------------------------------------
[[Page 60643]]
BGF Relocation
----------------------------------------------------------------------------------------------------------------
24-inch (61-cm) steel shell (vibratory) 10 6 9 12 6 419
24-inch (61-cm) steel shell (impact, 46 6 72 41 15 736
attenuated) *.........................
30-inch (76.2-cm) steel shell 33 17 28 39 19 2,006
(vibratory)...........................
30-inch (76.2-cm) steel shell (impact, 40 5 61 35 13 464
attenuated) *.........................
36-inch (91.4-cm) steel shell 18 10 16 21 11 1,167
(vibratory)...........................
36-inch (91.4-cm) steel shell (impact, 100 13 154 88 33 736
attenuated) *.........................
42-inch (106.7-cm) steel shell 28 11 23 36 12 21,544
(vibratory)...........................
----------------------------------------------------------------------------------------------------------------
* 5 dB reduction in sound assumed due to use of bubble curtain.
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 San Francisco Bay, PG&E reviewed several resources and datasets to
estimate marine mammal occurrence. These datasets include (but are not
limited to):
<bullet> 5 years of sighting and stranding data from The Marine
Mammal Center (TMMC) (NMFS, 2021b as cited by Integral Consulting Inc.,
2025a) and California Academy of Sciences (CAS) (NMFS, 2021a as cited
by Integral Consulting Inc., 2025a);
<bullet> Monitoring data collected over 5 days in Remedial Response
Areas A, B, and C in 2020 during sediment investigations in the initial
phase of the sediment remediation project (Haase, 2021);
<bullet> Monitoring data collected over 11 days of construction in
Remedial Response Areas A and B in the Spring of 2025 (Integral
Consulting Inc., 2025b);
<bullet> Counts from nearby haulouts; and
<bullet> Citizen-reported live sightings from <a href="https://www.iNaturalist.org">https://www.iNaturalist.org</a>;
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 the vicinity of the
project.
Gray Whale
Gray whales may enter the Bay in late winter and early spring or in
the fall during their migrations and, in recent years, there have been
an increased number of gray whales in the western and Central Bay
(Integral Consulting Inc., 2025a). During construction in March-April
2025, multiple gray whales were observed in San Francisco Bay (Integral
Consulting Inc., 2025b). According to TMMC, in June 2025, 9 individual
gray whales were observed in June over 14 days (TMMC, unpublished
data). PG&E estimates that one gray whale will occur in the project
area every other day (0.5 whales/day), and NMFS concurs with this
approach.
Bottlenose Dolphin
Historically, observations of bottlenose dolphins have occurred
west of Treasure Island and were concentrated 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 (Integral Consulting Inc., 2025a). In February 2019, an adult
and juvenile were seen on two separate occasions northwest of the
Oakland Inner Harbor, approximately 4 mi (6.4 km) from PG&E's proposed
project area (Integral Consulting Inc., 2025a). No bottlenose dolphins
were observed during pre-construction monitoring in 2020 (Haase, 2021)
or during construction in the spring of 2025 (Integral Consulting Inc.,
2025b). Although bottlenose dolphins are relatively uncommon in San
Francisco Bay, NMFS conservatively assumes that one group of bottlenose
dolphins will be present in the project area per month of construction.
A group size is estimated to be five animals based on sightings of
bottlenose dolphins in San Francisco Bay (Integral Consulting Inc.,
2025a).
Harbor Porpoise
Harbor porpoise are primarily seen near the Golden Gate Bridge,
Marin County, and the city of San Francisco on the northwest side of
San Francisco Bay (Keener et al., 2012; Stern et al., 2017). CAS
recorded 29 harbor porpoises (only 2 of which were alive) over the past
5 years, and <a href="https://www.iNaturalist.org">https://www.iNaturalist.org</a> recorded 11 harbor porpoise in
San Francisco Bay over the past 2 years. During 2020 monitoring, an
individual harbor porpoise was seen within the project area on 2 of the
5 monitoring days (Haase, 2021), and a single harbor porpoise was
observed within the Level B harassment zone during 11 days of
monitoring in the spring of 2025 (Integral Consulting Inc., 2025b).
PG&E estimates that two harbor porpoises will occur within the project
area per day, and NMFS concurs.
California Sea Lion
Remedial Response Area C, where PG&E proposes to conduct
construction, is adjacent to the Pier 39 K-Dock where California sea
lions regularly haul out. The Sea Lion Center at Pier 39 regularly
counted the sea lions at K-Dock from 1991 through 2018, and from 2016
through 2018, the yearly average ranged from 89 to 229 animals per day,
and the average over all 3 years was 191 (Integral Consulting Inc.,
2025a). Over 5 days of monitoring in 2020, a total of 463 sea lions
were observed, ranging from 56 to 129 per day (Haase, 2021). During
construction in March and April 2025, California sea lions were seen on
each of 11 monitoring days, with a total of 92 California sea lions
seen, ranging from 3 to 18 California sea lions per day (Integral
Consulting Inc., 2025b). Although there are times of year when the K-
Dock is unoccupied or there are few individuals present, it is
difficult to predict abundance based on the time of year. Therefore,
PG&E is conservatively assuming 191 sea lions per day, based on the
average K-dock counts, and NMFS concurs.
Northern Fur Seal
TMMC recorded 44 northern fur seals in San Francisco Bay from 2016
to 2021 (NMFS, 2021b). CAS recorded an additional 3 for a total of 47
over 5 years (NMFS, 2021a), yielding 0.03 norther fur seals per day, or
approximately 10
[[Page 60644]]
northern fur seals per year. No fur seals were observed during
monitoring efforts in 2020 and 2025 (Integral Consulting Inc., 2025b;
Haase, 2021). In the fall and winter, northern fur seals occasionally
strand on Yerba Buena Island and Treasure Island (Integral Consulting
Inc., 2025a), approximately 2 mi (3.2 km) from PG&E's proposed project
area. Using PG&E's assumption of approximately 0.03 fur seals per day
over the course of 62 days of pile driving plus a history of known fur
seal strandings near the project area, NMFS has determined it
appropriate to assume 5 fur seals in the project area over the course
of construction.
Steller Sea Lion
Steller sea lions are rare in San Francisco Bay. TMMC recorded four
Steller sea lions in San Francisco Bay from 2016 to 2021 (NMFS, 2021b),
and CAS recorded no Steller sea lions over the same time frame (NMFS,
2021a). 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 male Steller sea lion had been
observed using the Pier 39 K-Dock haulout intermittently during July
and August and occasionally September (Integral Consulting Inc.,
2025a). No Steller sea lions were observed during the 2020 or 2025
monitoring (Haase, 2021; Integral Consulting Inc., 2025b). Given the
known occasional occurrences of Steller sea lions at Pier 39, NMFS
feels it is appropriate to assume five Steller sea lions in PG&E's
proposed project area during the time period of construction.
Harbor Seal
Harbor seals in San Francisco Bay forage mainly within 7 mi (11.3
km) of their primary haulout site (Grigg et al., 2012) and often within
just 1-3 mi (1.6-4.8 km) (Torok, 1994). The only harbor seal haulout
within 7 mi (11.3 km) of the project site is Yerba Buena Island, which
is 3.1 mi (5 km) to the east of the Project Area. Aside from the
vibratory removal of 42-inch (106.7-cm) steel shell piles, the largest
Level B harassment zone is 2,006 m (vibratory installation of 30-inch
[76.2 cm]), and the Level B harassment isopleths are not expected to
reach the Yerba Buena haulout. However, harbor seals that use this
haulout are likely to forage within ensonified areas from the project.
During 5 days of monitoring in 2020, 60 harbor seals were observed,
with a maximum of 20 seals observed in one day (Haase, 2021). During 11
days of monitoring in 2025, two harbor seals were observed in the
project area (Integral Consulting Inc., 2025b). Based on this data,
PG&E assumes 20 harbor seals will be within the Level B harassment
isopleth per day, and NMFS concurs.
PG&E proposes to conduct vibratory removal of 42-inch (106.7-cm)
steel shell piles over 2 days (one pile per day). The Level B
harassment isopleth for the vibratory removal of the 42-inch (106.7-cm)
steel shell pile is 21,544 m. This isopleth would extend to Castro
Rocks in northern San Francisco Bay, which is a well-known harbor seal
haulout, and therefore, PG&E proposes to add harbor seals from Castro
Rocks haulout to the take determined by the daily occurrence estimate
described above. The National Park Service conducts annual surveys of
haulouts in San Francisco Bay. Over the past 10 years of surveys, the
highest mean number of harbor seals observed at Castro Rocks was 237
seals (in 2019) (Codde, 2020; Codde & Allen, 2017, 2018, 2020, 2025).
The vibratory removal of 42-inch (106.7-cm) steel shell piles is
expected to last approximately 20 minutes each day. PG&E estimates that
50 harbor seals from Castro Rocks will occur within the Level B
harassment isopleth during each day of vibratory removal of 42-inch
(106.7-cm) steel shell piles, resulting in 100 harbor seals.
Northern Elephant Seal
TMMC recorded 903 northern elephant seals in San Francisco Bay from
2016 to 2021 (NMFS, 2021b). The CAS reported an additional 6 northern
elephant seals over the same time frame (NMFS, 2021a), for a total of
909 seals, yielding an average of 0.5 elephant seals per day. No
northern elephant seals were observed during monitoring efforts
conducted in 2020 and 2025 (Haase, 2021; Integral Consulting Inc.,
2025b). In order to ensure sufficient authorization of northern
elephant seal takes, PG&E assumed 0.5 elephant seals will occur in the
proposed project area per day (i.e., one elephant seal every 2 days).
NMFS concurs with this assumption.
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.
To estimate take by Level B harassment for gray whale, harbor
porpoise, California sea lion, and northern elephant seal the expected
daily occurrence was multiplied by the estimated number of 62 pile
driving days (see table 9). Similarly, for harbor seals, the expected
daily occurrence was multiplied by the estimated number of 62 pile
driving days and 100 harbor seals was added to this number to account
for take of harbor seals at Castro Rocks during 2 days of vibratory
removal of 42-inch (106.7-cm) steel shell piles (50 harbor seals per
day) (see table 9). For northern fur seals and Steller sea lions, PG&E
is assuming five animals of each species will occur in the proposed
project area during the course of PG&E's construction (see table 9).
For bottlenose dolphins, PG&E estimates that one group of five
bottlenose dolphins will occur in the proposed project area per month
of pile driving. Based on 5 months of pile driving, NMFS proposes to
authorize 25 takes of bottlenose dolphins by Level B harassment (table
9).
Table 9--Estimated Take by Level B Harassment Proposed for Authorization
----------------------------------------------------------------------------------------------------------------
Estimated
take by Stock Percent
Species Stock Expected occurrence Level B abundance of stock
harassment
----------------------------------------------------------------------------------------------------------------
Gray whale..................... Eastern North 0.5 whales/day........ 31 26,960 0.1
Pacific.
Bottlenose dolphin............. California coastal 5 dolphins/month of 25 453 5.5
construction.
Harbor porpoise................ San Francisco/ 2 porpoises/day....... 124 7,777 1.6
Russian River.
California sea lion............ United States..... 191 sea lions/day..... 11,842 257,606 4.6
Northern fur seal.............. Eastern Pacific... 5 seals over project 5 626,618 <0.1
duration.
California........ 14,050 <0.1
Steller sea lion............... Eastern........... 5 sea lions over 5 36,308 <0.1
project duration.
[[Page 60645]]
Harbor seal.................... California........ 20 harbor seals/day 1,340 30,968 4.3
for 62 days +50 seals/
day for 2 days of
vibratory removal of
42-inch steel shell
piles (see Marine
Mammal Occurrence
section above).
Northern elephant seal......... California 0.5 seals/day......... 31 187,386 <0.1
breeding.
----------------------------------------------------------------------------------------------------------------
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
(ITAs) 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 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.
The mitigation requirements described in the following were
proposed by PG&E in its adequate and complete application or are the
result of subsequent coordination between NMFS and PG&E. PG&E has
agreed that all of the mitigation measures are practicable. NMFS has
fully reviewed the specified activities and the mitigation measures to
determine if the mitigation measures would result in the least
practicable adverse impact on marine mammals and their habitat, as
required by the MMPA, and has determined the proposed measures are
appropriate. NMFS describes these below as proposed mitigation
requirements, and has included them in the proposed IHA.
Shutdown Zones
PG&E must establish shutdown zones for all pile driving activities.
The purpose of a shutdown zones is generally to define an area within
which shutdown of the activity would occur upon sighting of a marine
mammal (or in anticipation of an animal entering the defined area).
Shutdown zones will vary based on the activity type and marine mammal
hearing group (see table 10). Specifically, PG&E will establish
shutdown zones for otariids based on the otariid Level A harassment
zone and shutdown zones for all other marine mammals based on the
largest Level A harassment zone for each pile size/type and driving
method, as shown in table 10. A minimum shutdown zone of 10 m would be
required for all in-water construction activities to avoid physical
interaction with marine mammals.
Table 10--Proposed Shutdown Zones
----------------------------------------------------------------------------------------------------------------
Otariid Shutdown zone for
Pile type Hammer type shutdown zone all other marine
(m) mammals (m)
----------------------------------------------------------------------------------------------------------------
Turbidity Curtain
----------------------------------------------------------------------------------------------------------------
Steel shell pile <12 inch................... Vibratory..................... 10 10
Steel shell pile <12 inch................... Impact (attenuated)........... 10 15
----------------------------------------------------------------------------------------------------------------
Slope Stabilization
----------------------------------------------------------------------------------------------------------------
18-inch tapered timber...................... Vibratory..................... 10 25
18-inch tapered timber...................... Impact (attenuated)........... 10 10
----------------------------------------------------------------------------------------------------------------
BGF Relocation
----------------------------------------------------------------------------------------------------------------
24-inch steel shell......................... Vibratory..................... 10 15
24-inch steel shell......................... Impact (attenuated)........... 15 75
30-inch steel shell......................... Vibratory..................... 20 40
30-inch steel shell......................... Impact (attenuated)........... 15 65
36-inch steel shell......................... Vibratory..................... 15 25
36-inch steel shell......................... Impact (attenuated)........... 35 155
42-inch steel shell......................... Vibratory..................... 15 40
----------------------------------------------------------------------------------------------------------------
[[Page 60646]]
Prior to pile driving, shutdown zones will be established based on
zones represented in table 10. Protected species observers (PSOs) 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 a PSO 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.
If a species for which authorization has not been granted, or a
species which has been granted but the authorized takes are met, is
observed approaching or within the Level B harassment zone, pile
driving activities will be shutdown. Activities will not resume until
the animal has been confirmed to have left the area or 15 minutes has
elapsed with no sighing of the animal.
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.
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 zones for
a period of 30 minutes. The shutdown zone would be considered cleared
when a marine mammal has not been observed within the zone for a 30-
minute period. If a marine mammal is observed within shutdown zones,
pile driving activity would be delayed or halted. When a marine mammal
for which take by Level B harassment is authorized is present in the
Level B harassment zone, activities may begin and take by Level B
harassment will be recorded. 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
change 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 driving.
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.
NMFS conducted an independent evaluation of the proposed measures,
and 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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> 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);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
<bullet> Mitigation and monitoring effectiveness.
The monitoring and reporting requirements described in the
following were proposed by PG&E in its adequate and complete
application and/or are the result of subsequent coordination between
NMFS and PG&E. PG&E has agreed to the requirements. NMFS describes
these below as requirements and has included them in the proposed IHA.
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 and removal must be conducted by NMFS-approved PSOs in a
manner consistent with the following:
<bullet> PSOs must be independent of the activity contractor (for
example,
[[Page 60647]]
employed by a subcontractor) and have no other assigned tasks during
monitoring periods;
<bullet> At least one PSO would have prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS'
issued ITA;
<bullet> Other PSOs may substitute education (degree in biological
science or related field) or training for experience;
<bullet> 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;
<bullet> PSOs must be approved by NMFS prior to beginning any
activity subject to the IHA.
PSOs should have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behavior;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> 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
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to prove 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 the 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, 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.
Hydroacoustic Monitoring
Hydroacoustic monitoring, to be conducted for purposes of measuring
sound source levels and sound propagation, will be conducted in
accordance with a NMFS-approved acoustic monitoring plan. PG&E plans to
conduct hydroacoustic monitoring throughout the entirety of the
sediment remediation project, which is expected to span over multiple
ITAs. Across the entire project, PG&E will collect data on a
representative number of piles (at least 10 percent of each pile type
and installation method). Given that PG&E's proposed hydroacoustic
monitoring effort would span multiple IHAs, specific effort under any
given IHA may vary. Therefore, under this proposed IHA, PG&E will only
conduct hydroacoustic monitoring for pile types/installation methods
for which hydroacoustic monitoring has not been previously conducted.
PG&E may request that NMFS adjust the shutdown zones and revise the
Level A and Level B harassment zones, as appropriate, pending NMFS'
review and approval of the results of acoustic monitoring.
Reporting
Marine Mammal Monitoring Report
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
of 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:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including: (a) the number and type of piles that
were driven and the method (e.g., impact, vibratory); and (b) total
duration of driving time for each pile (vibratory driving) and number
of strikes for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring;
<bullet> 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;
<bullet> Upon observation of a marine mammal, the following
information 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 the pile being driven 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); and (i) description of any actions implemented in
response to the sighting (e.g., delays, shutdown) and time and location
of the action;
<bullet> Number of marine mammals detected within the harassment
zones, by species; and
<bullet> Summary 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.
[[Page 60648]]
Hydroacoustic Monitoring Report
The hydroacoustic monitoring report must, at minimum, include the
following:
<bullet> Hydrophone equipment and methods, recording device,
sampling rate, distance (m) from the pile where recordings were made;
depth of water and recordings device(s);
<bullet> Type and size of pile being driven, substrate type, method
of driving during recordings (e.g., hammer model and energy), and total
pile driving duration;
<bullet> Whether a sound attenuation device is used and, if so, a
detailed description of the device used and the duration of its use per
pile;
<bullet> For impact pile driving (per pile): Number of strikes and
strike rate; depth of substrate to penetrate; pulse duration and mean,
median, and maximum sound levels (dB re: 1 [micro]Pa): root mean square
sound pressure level (SPL<INF>rms</INF>); cumulative sound exposure
level (SEL<INF>cum</INF>), peak sound pressure level
(SPL<INF>peak</INF>), and single-strike sound exposure level
(SEL<INF>s-s</INF>);
<bullet> For vibratory driving/removal (per pile): Duration of
driving per pile; mean, median, and maximum sound levels (dB re: 1
[micro]Pa): root mean square sound pressure level (SPLrms), cumulative
sound exposure level (SELcum) (and timeframe over which the sound is
averaged);
<bullet> One-third octave band spectrum and power spectral density
plot; and
<bullet> Transmission loss values for each pile size and type and
installation method, when appropriate.
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 must report the
incident to the Office of Protected Resources, NMFS
(<a href="/cdn-cgi/l/email-protection#4d1d1f6304191d630022232439223f24232a1f283d223f393e0d23222c2c632a223b"><span class="__cf_email__" data-cfemail="8fdfdda1c6dbdfa1c2e0e1e6fbe0fde6e1e8ddeaffe0fdfbfccfe1e0eeeea1e8e0f9">[email protected]</span></a>) 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 IHA. PG&E would not resume their activities until notified by
NMFS. The report would include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
the species listed in table 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 62 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 is
proposed 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
[[Page 60649]]
injury 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 pile driving 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:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> The specified activities and associated ensonified areas
are very small relative to the overall habitat ranges of all species;
<bullet> The project area does not overlap known BIAs or ESA-
designated critical habitat;
<bullet> The lack of anticipated significant or long-term effects
or marine mammal habitat; and
<bullet> 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 section 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 (see 86 FR
5322, January 19, 2021). 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 proposes to authorize is below one-third of
the estimated stock abundances for all stocks (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.
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 ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency ensures 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 ITAs, NMFS
consults internally whenever we propose to authorize take for ESA-
listed 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 PG&E for conducting pile driving activities in San
Francisco Bay, provided the previously mentioned mitigation,
monitoring, and reporting requirements are incorporated. A draft of the
proposed IHA can be found at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
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. 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:
<bullet> 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).
<bullet> 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
[[Page 60650]]
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.
<bullet> 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: December 19, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2025-23798 Filed 12-23-25; 8:45 am]
BILLING CODE 3510-22-P
</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>Indexed from Federal Register on December 29, 2025.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.