Notice2023-06744
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Chevron Long Wharf Maintenance and Efficiency Program in San Francisco Bay, California
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
March 31, 2023
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from Chevron Products Company for authorization to take marine mammals incidental to the Long Wharf Maintenance and Efficiency Program (LWMEP) in San Francisco Bay, California. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, one-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 88 Issue 62 (Friday, March 31, 2023)</title>
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[Federal Register Volume 88, Number 62 (Friday, March 31, 2023)]
[Notices]
[Pages 19247-19267]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-06744]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XC798]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Chevron Long Wharf Maintenance
and Efficiency Program in San Francisco Bay, California
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for
[[Page 19248]]
comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from Chevron Products Company for
authorization to take marine mammals incidental to the Long Wharf
Maintenance and Efficiency Program (LWMEP) in San Francisco Bay,
California. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS
is requesting comments on its proposal to issue an incidental
harassment authorization (IHA) to incidentally take marine mammals
during the specified activities. NMFS is also requesting comments on a
possible one-time, one-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision.
DATES: Comments and information must be received no later than May 1,
2023.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
<a href="/cdn-cgi/l/email-protection#4c05181c62382d3520233e0c22232d2d622b233a"><span class="__cf_email__" data-cfemail="afe6fbff81dbced6c3c0ddefc1c0cece81c8c0d9">[email protected]</span></a>.
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="http://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">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: Jessica Taylor, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: <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 above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has
preliminarily determined that the issuance of the proposed IHA
qualifies to be categorically excluded from further NEPA review. We
will review all comments submitted in response to this notice prior to
concluding our NEPA process or making a final decision on the IHA
request.
Summary of Request
On December 16, 2022, NMFS received a request from Chevron Products
Company (Chevron) for an IHA to take marine mammals incidental to pile
driving activities associated with the LWMEP in San Francisco Bay (the
Bay), California. Following NMFS' review of the application, Chevron
submitted a final revised version on February 27, 2023. The application
was deemed adequate and complete on March 20, 2023. Chevron's request
is for take of 7 species of marine mammals by Level B harassment only.
Neither Chevron nor NMFS expect serious injury or mortality to result
from this activity and, therefore, an IHA is appropriate.
NMFS previously issued IHAs to Chevron for similar work (83 FR
27548, June 13, 2018; 84 FR 28474, June 19, 2019; 85 FR 37064, June 19,
2020; 86 FR 28578, May 27, 2021; 87 FR 35180, June 9, 2022). Chevron
complied with all the requirements (e.g., mitigation, monitoring, and
reporting) of the previous IHAs and information regarding their
monitoring results may be found in the Estimated Take section.
This proposed IHA would cover 1 year of a larger project for which
Chevron obtained prior IHAs and intends to request take authorization
for subsequent facets of the project. The larger 5-year project
involves upgrading Long Wharf to satisfy current Marine Oil Terminal
Engineering and Maintenance Standards.
Description of Proposed Activity
Overview
Chevron plans to upgrade Berth 1 of the Refinery Long Wharf in the
Bay, California in order to meet current safety and efficiency
standards. As part of the proposed project, Chevron is proposing to use
vibratory extraction to remove concrete piles associated with the
existing gangway and catwalk. Impact hammers would be used to install
concrete piles to construct a mooring dolphin and hook, breasting
dolphin and breasting points with standoff fenders, and to replace the
catwalk in a different location. A temporary construction template
composed of steel piles would be installed through the use of a
vibratory hammer and removed by vibratory extraction when in-water
construction activities are complete. The Long Wharf
[[Page 19249]]
has six berths for receiving raw materials and shipping products. The
project area encompasses the entirety of Berth 1, an area of
approximately 470 square meters (m\2\). All in-water work would take
place within the seasonal work window of June 1, 2023 through November
30, 2023.
Chevron's proposed activity includes impact and vibratory pile
driving and vibratory pile removal, which may result in the incidental
take of marine mammals, by harassment only. Due to mitigation measures,
no Level A harassment is anticipated to occur, and none is proposed for
authorization.
Dates and Duration
In-water construction activities would occur over the course of 30
days from June 1, 2023 through November 30, 2023. Chevron states that
it would conduct work only in daylight hours. The proposed in-water
work schedule is shown in table 1. In-water work would begin with of 1
day of vibratory pile extraction, then 21 days of impact pile
installation. The temporary construction trestle would require 4 days
of vibratory pile installation and 4 days of vibratory pile removal.
Pile installation and removal would occur at a rate 2-3 piles per day,
depending upon pile size and type. Only one pile would be driven or
extracted at a time. Although the IHA would be active for a period of 1
year, in-water pile installation and removal activities are planned
from June through November to protect sensitive life stages of listed
fish species in the area.
Table 1--In-Water Construction Schedule
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Estimated
Estimated duration per
Pile type Method Number of strikes per pile in Estimated Total
piles pile minutes number per day estimated days
(seconds)
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch square concrete pile.............. Impact install.............. 42 440 \1\ 20 (1200) 2 21
36-inch steel shell pile \2\.............. Vibratory install........... 12 N/A 10 (600) 3 4
18-inch concrete pile..................... Vibratory extract........... 2 N/A 6.67 (400) 2 1
36-inch steel shell pile \2\.............. Vibratory extract........... 12 N/A 10 (600) 3 4
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\1\ Using a DelMag D62 22 or similar diesel hammer.
\2\ Temporary template.
Specific Geographic Region
The Long Wharf is located in northern region of the central Bay,
south of the eastern terminus of the Richmond-San Rafael Bridge (RSRB)
(Figure 1). Water depth in the project area ranges from approximately 6
to 15 meters (m), mean lower low water (MLLW). The substrate is
primarily Bay mud, however, sand or gravel may exist deeper into the
substrate. The project area around Berth 1 is approximately 470 square
kilometers (km\2\) in size. Ambient underwater noise in the vicinity of
the project area is generated by shipping activity, ferry traffic, and
sound generated by the Richmond Bridge piers. Underwater noise
measurements in 2006 and from 2020-2022 found the ambient noise in the
project area to exceed 120 dB RMS. Ambient underwater noise levels at
Long Wharf may vary with noise levels being higher at Berth 1, likely
due to its closer proximity to the main shipping channel.
BILLING CODE 3510-22-P
[[Page 19250]]
[GRAPHIC] [TIFF OMITTED] TN31MR23.025
BILLING CODE 3510-22-C
Figure 1--Chevron Long Wharf Project Area
Detailed Description of the Specified Activity
The LWMEP upgrades began in 2018 and were planned to be completed
within 2-3 years, however, the project experienced several delays. The
proposed IHA would cover activities that were not completed under the
2021 IHA (86 FR 28578, May 27, 2021).
Chevron plans to complete modifications to Berth 1 at the Long
Wharf by updating the fender system to better accommodate barges and
enable balanced utilization across berths. Specifically, these
modifications include replacing the gangway, construction of a new
mooring dolphin and hook and breasting dolphin with breasting point,
removing a catwalk and concrete piles, and installing a temporary
construction template. Unless otherwise specified, the term ``pile
driving'' in this section, and all following sections, may refer to
either pile installation or removal.
Gangway Replacement--The existing gangway would be replaced in
order to accommodate barges. Four 24-inch concrete piles would be
installed using an impact hammer at a rate of 2 piles per day (table
1). A new raised fire monitor would be added as well. However, addition
of the fire monitor would occur above water, and therefore, we do not
anticipate take of marine mammals associated with this activity, and it
is not discussed further.
Mooring Dolphin and Hook Construction--A new 24 feet (ft) (7.3
meters (m)) by 25 ft (7.6 m) mooring dolphin and hook would be
installed to accommodate barges at Berth 1. An impact hammer would be
used to drive 13 24-inch concrete piles at a rate of 2 piles per day
(table 1).
Breasting Dolphin and Breasting Point Construction--A new 24 ft
(7.3 m) by 25 ft (7.6 m) breasting dolphin would be installed with a 13
ft (4 m) by 26 ft (7.9 m) breasting point with standoff fenders to
accommodate barges. The breasting dolphin would be constructed using an
impact hammer to install 17 24-inch concrete piles at a rate of 2 piles
per day (table 1). The breasting point with standoff fenders would be
installed using an impact hammer to drive 8 24-inch concrete piles at a
rate of 2 piles per day. Construction of the breasting dolphin and
breasting point also require the removal of an existing catwalk and 2
18-inch concrete piles. These piles
[[Page 19251]]
would be removed through the use of vibratory extraction over 1 day.
The existing catwalk would be replaced by a new catwalk in a different
location. Removal and replacement of the catwalk would occur above
water, and therefore, we do not anticipate take of marine mammals
associated with this activity, and it is not discussed further.
In addition to the planned modifications, Chevron would construct a
temporary template using 12 36-inch steel piles. These piles would be
installed using vibratory installation and removed using vibratory
extraction after in-water construction activities are complete.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, incorporated here by reference, instead of
reprinting the information. Additional information regarding population
trends and threats may be found in NMFS' Stock Assessment Reports
(SARs; <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">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 2 lists all species or stocks for which take is expected and
proposed to be authorized for this activity, and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality from
anthropogenic sources are included here as gross indicators of the
status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Pacific SARs. All values presented in table 2 are the most
recent available at the time of publication (including from the draft
2022 SARs) and are available online at: <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 2--Marine Mammal Species \4\ Likely To Be Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray whale...................... Eschrichtius robustus.. Eastern North Pacific.. -, -, N 26,960 (0.05, 25,849, 801 131
2016).
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Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Bottlenose dolphin.............. Tursiops truncatus..... California Coastal..... -, -, N 453 (0.06, 346, 2011). 2.7 >=2.0
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... San Francisco/Russian -, -, N 7,777 (0.62, 4,811, 73 >=0.4
River. 2017).
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Order Carnivora--Pinnipedia
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Family Otariidae (eared seals and
sea lions):
California sea lion............. Zalophus californianus. U.S.................... -, -, N 257,606 (N/A, 233,515, 14,011 >321
2014).
Northern fur seal \5\........... Callorhinus ursinus.... California............. -, D, N 14,050 (N/A, 7,524, 451 1.8
2013).
Family Phocidae (earless seals):
Harbor seals.................... Phoca vitulina......... California............. -, -, N 30,968 (N/A, 27,348, 1,641 43
2012).
Northern elephant seal.......... Mirounga angustirostris California Breeding.... -, -, N 187,386 (N/A, 85,369, 5,122 13.7
2013).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <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> assessments/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable as in the case of
the pinnipeds, as population estimates are dependent upon the numbers of individuals hauled out or the number of pups.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<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>; Committee on Taxonomy (2022)).
\5\ Survey years = Sea Lion Rock--2014; St. Paul and St. George Is--2014, 2016, 2018; Bogoslof Is.--2015, 2019.
[[Page 19252]]
As indicated above, all 7 species (with 7 number managed stocks) in
table 2 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. All species that could
potentially occur in the proposed survey areas are included in table 4-
1 of the IHA application. While humpback whales have been sighted in
the coastal waters outside of the Bay, the spatial occurrence of this
species is such that take is not expected to occur, and they are not
discussed further beyond the explanation provided here. Although there
are no published studies available regarding the distribution of
humpback whales in the Bay, sightings from whale watching vessels and
other mariners report that when humpback whales enter the Bay, they
rarely move east into the Bay towards the vicinity of the project area
and are unlikely to occur during the proposed activities.
Harbor Seal
Pacific harbor seals are distributed from Baja California north to
the Aleutian Islands of Alaska. Harbor seals do not make extensive
pelagic migrations, but may travel hundreds of kilometers to find food
or suitable breeding areas (Herder, 1986; Harvey and Goley, 2011;
Carretta et al., 2022).
The California Department of Transportation (Caltrans) conducted
extensive marine mammal surveys in Bay before and during seismic
retrofit on the RSRB from 1998-2002 and determined that a minimum of
500 harbor seals occur within the Bay (Green et al., 2002). This
estimate aligns with more recent seal counts (Lowry et al., 2008; Codde
et al., 2020). The California harbor seal stock may be stabilizing at
or near carrying capacity, although conservation concerns such as
vessel strikes, disturbance, fishing gear entanglement, and habitat
loss are still a concern in the Bay area (Duncan, 2019).
The number of harbor seals in the Bay increases during the winter
foraging period as compared to the spring breeding season. In the Bay,
harbor seals are known to forage on a variety of fish, crustaceans, and
cephalopods found in shallow intertidal waters.
Seals primarily haul out on remote mainland and island beaches,
reefs, and estuary areas. At haul-outs, they congregate to rest,
socialize, breed, and molt. Haul out sites are consistent for harbor
seals across years (Kopec and Harvey, 1995), and females may return to
their natal sites for breeding (Green et al., 2006). The nearest major
haul out site to the project area is Castro Rocks, located
approximately 1,400 meters (0.87 miles) north of the Berth 1 of Long
Wharf. Use of Castro Rocks as a haul out site has been increasing over
the years (Codde et al., 2020). Seals haul out on Castro Rocks year-
round during medium to low tides, and usage of this haul out site is
highest during the summer molting period of June-July. During the LWMEP
2020-2021 construction period, protected species observers (PSOs)
observed the number of harbor seals on Castro Rocks to vary greatly,
from 0 to 90 individuals, depending upon the tide level (AECOM, 2021).
Due to the proximity of Long Wharf to the Castro Rocks haul out site
and previous monitoring conducted by Chevron, it is likely that harbor
seals would be in the project area during construction activities.
California Sea Lion
California sea lions are mainly seen swimming off the San Francisco
and Marin shorelines within the Bay, but may occasionally enter the
project area to forage. They feed seasonally on schooling fish and
cephalopods, including salmon, herring, sardines, anchovy, mackerel,
whiting, rockfish, and squid (Lowry et al., 1990, 1991; Weise 2000;
Carretta et al., 2022; Lowry et al., 2022). In central California sea
lion populations, short term seasonal variations in diet are related to
prey movement and life history patterns while long-term annual changes
correlate to large-scale ocean climate shifts and foraging competition
with commercial fisheries (Weise and Harvey, 2008; McClatchie et al.,
2016). Conservation concerns for California sea lions include prey
species availability due to climate change, vessel strikes, non-
commercial fishery human caused mortality, hookworms, and competition
for forage with commercial fisheries (Carretta et al., 2018; Carretta
et al., 2022).
Although California sea lions forage and conduct many activities
within the water, they also use haul outs on land. In the Bay, sea
lions haul out primarily on floating docks at Pier 39 at the
Fisherman's Wharf area of the San Francisco Marina, approximately 12.5
kilometers (7.8 miles) southwest of the project area. Haul out numbers
at Pier 39 vary seasonally. In addition to the Pier 39 haul out,
California sea lions haul out on buoys, wharfs, and similar structures
throughout the Bay.
Occurrence of sea lions in the Bay is typically lowest in June
during the breeding season and higher during El Ni[ntilde]o seasons. In
the Bay, California sea lions have been observed foraging near Pier 39,
in the shipping channel south of Yerba Buena Island, and along the west
and north sides of the Long Wharf (AECOM, 2019). The relatively deep
shipping channel west and north of the Point Orient Wharf also provides
foraging area for sea lions. PSOs observed up to 13 sea lions within a
construction season during prior monitoring efforts for the LWMEP
(AECOM, 2021). As sea lions may forage widely throughout the Bay, this
species may enter the project area during construction activities.
Harbor Porpoise
Harbor porpoises typically occur in cool temperate to sub-polar
waters less than 62.6 degrees Fahrenheit (17 degrees Celsius) (Read
1999) where prey aggregations are concentrated (Watts and Gaskin,
1985). In the eastern Pacific, harbor porpoises occur in coastal and
inland waters from Point Conception, California to Alaska (Gaskin
1984). The non-migratory San Francisco-Russian River stock ranges from
Pescadero to Point Arena, California, utilizes relatively shallow
nearshore waters (<100 meters), and feeds on small schooling fishes
such as northern anchovy and Pacific herring which enter the Bay
(Caretta et al., 2022; Stern et al., 2017). Harbor porpoises tend to
occur in small groups and are considered to be relatively cryptic
animals.
Before 2008, harbor porpoises occurred primarily outside of the Bay
although the Bay has historically been considered habitat for harbor
porpoises (Broughton, 1999). Recently, observations of harbor porpoises
within the Bay have become more common (Duffy 2015; Stern et al., 2017;
AECOM, 2021). From 2011-2014, the Golden Gate Cetacean Research (GGCR)
program conducted a visual count and identified 2,698 porpoise groups
from the Golden Gate Bridge during 96 percent of their on-effort survey
days (Stern et al., 2017). During 2021 LWMEP monitoring, PSOs observed
harbor porpoises swimming past the Bay side of the Long Wharf on four
different occasions (AECOM, 2021). Harbor porpoise movements into the
Bay are linked to tidal cycle with the greatest numbers of porpoises
sighted during high tide to ebb tide periods. Movements into the Bay
are likely influenced by prey availability (Duffy 2015; Stern et al.,
2017) and may serve as a foraging area. Although harbor porpoise
sightings are generally concentrated in the vicinity of the Golden Gate
Bridge and Angel Island, southwest of the project site (Keener, 2011),
this species is occurring more frequently in the Bay east of Angel
Island and may approach the project area during pile driving
activities.
[[Page 19253]]
Bottlenose Dolphin
The common bottlenose dolphin is found in all oceans across the
globe, and is one of the most commonly observed marine mammal species
in coastal waters and estuaries. Two genetically distinct stocks occur
off the coast of California, the California coastal stock and the
California/Oregon/Washington offshore stock. The range of the
California coastal stock has been expanding north since an El
Ni[ntilde]o event in 1982-1983 (Hansen and Defran, 1990; Wells et al.,
1990) and spans as far north as Sonoma County (Keener et al., 2023).
From 2010-2018, a photo-identification monitoring study identified 84
distinctive individual bottlenose dolphins in the Bay, likely belonging
to the California coastal stock (Keener et al., 2023). This stock shows
little site fidelity and individuals are highly mobile (Weller et al.,
2016). Since 2008, coastal bottlenose dolphins have been observed
regularly in the Bay, mainly in proximity to the Golden Gate near the
mouth of the Bay (Bay Nature, 2020). PSOs did not observe bottlenose
dolphins during prior monitoring efforts for the LWMEP. However, due to
increased numbers of dolphins occurring in the Bay, it is possible that
a limited number of individuals may approach the project area during
in-water construction activities.
Gray Whale
Gray whales are one of the most common whales along the California
coast. A small number of whales, known as the Pacific Coast Feeding
Group (PCFG), are known to feed along the Pacific coast between Kokiak
Island, AK and northern California, as well as in nearshore waters just
outside of the Bay (Carretta et al., 2022). The southward migration to
winter breeding grounds occurs from December through February while the
northward migration to the feeding grounds takes place from February
through May, peaking in March (NOAA NCOSS, 2007). A few individuals may
enter the Bay during the northward migration. Since 2019, it has become
more common for gray whales on their northward migration to enter the
Bay during the months of February and March to feed (Bartlett, 2022),
although many only travel up to 2 miles into the Bay (Self, 2012).
Although it is more likely that a gray whale would enter the Bay from
February to March, it is possible a gray whale may enter the project
area during pile driving activities.
Eastern North Pacific gray whales have been experiencing a UME
since 2019 when large numbers of whales began stranding from Mexico to
Alaska. As of March 14, 2023, approximately 307 gray whales have
stranded in the U.S. and 633 total throughout the U.S., Canada, and
Mexico since 2019 (NOAA, 2023). Preliminary necropsy results conducted
on a subset of the whales indicated that many whales showed signs of
nutritional stress, however, these findings are not consistent across
all of the whales examined (NOAA, 2023). This UME is ongoing and
similar to that of 1999 and 2000 when large numbers of gray whales
stranded along the eastern Pacific coast (Moore et al., 2001; Gulland
et al., 2005). Oceanographic factors limiting food availability for
whales was identified as a likely cause of the prior UME and may also
be influencing the current UME (LeBouef et al., 2000; Moore et al.,
2001; Minobe 2002; Gulland et al., 2005).
Northern Elephant Seal
Northern elephant seals breed and give birth in California and Baja
California, mainly on offshore islands during the months of December to
March (Stewart and Huber, 1993; Stewart et al., 1994; Carretta et al.,
2022). Molting season takes place from March to August. Adults
typically reside in offshore pelagic waters when not breeding or
molting, however, a healthy juvenile male was observed basking at
Aquatic Park in San Francisco in the spring of 2019 (Hern[aacute]ndez,
2020). PSOs did not observe northern elephant seals during prior
monitoring efforts for the LWMEP. Although rare visitors to the Bay, it
is possible that a few individuals may be present during construction
activities.
Northern Fur Seal
Northern fur seals range from southern California north to the
Bering Sea, and west to the Okhotsk Sea and Honshu Island, Japan in the
west (Carretta et al., 2022). The majority of the population breeds on
the Pribilof Islands in the southern Bering Sea, although a small
percentage of the population breed at San Miguel Island and the
Farallon Islands off the coast of California. Northern fur seals show
high site fidelity to breeding and rookery locations, and may swim long
distances for prey. Their diet is composed of small schooling fish such
as walleye Pollock, herring, hake, anchovy, and squid. Diet and
population trends vary with environmental conditions, such as El
Ni[ntilde]o (Carretta et al., 2022). The California stock of northern
fur seals forage in waters outside of the Bay. Juvenile northern fur
seals occasionally strand in the Bay, especially during El Ni[ntilde]o
events (TMMC 2016). The Marine Mammal Center (TMMC) responds to
approximately five northern fur seal strandings per year in the Bay
(TMMC, 2016). PSOs did not observe northern fur seals during prior
monitoring efforts for the LWMEP. Although rarely observed in the Bay,
it is possible individuals may be present during construction
activities.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in table 3.
[[Page 19254]]
Table 3--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Generalized hearing
Hearing group range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales).... 7 Hz to 35 kHz.
Mid-frequency (MF) cetaceans (dolphins, toothed 150 Hz to 160 kHz.
whales, beaked whales, bottlenose whales).
High-frequency (HF) cetaceans (true porpoises, 275 Hz to 160 kHz.
Kogia, river dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true seals). 50 Hz to 86 kHz.
Otariid pinnipeds (OW) (underwater) (sea lions 60 Hz to 39 kHz.
and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al., 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take section later in this document includes a
quantitative analysis of the number of individuals that are expected to
be taken by this activity. The Negligible Impact Analysis and
Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and whether those
impacts are reasonably expected to, or reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.
Acoustic effects on marine mammals during the specified activities
can occur from impact pile driving and vibratory pile driving and
removal. The effects of underwater noise from Chevron's proposed
activities have the potential to result in Level B harassment of marine
mammals in the project area.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (ANSI, 1995). The sound level of an area is
defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., waves, wind,
precipitation, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20
decibels (dB) from day to day (Richardson et al., 1995). The result is
that, depending on the source type and its intensity, sound from the
specified activities may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
In-water construction activities associated with the project would
include impact and vibratory pile driving and removal. The sounds
produced by these activities fall into one of two general sound types:
impulsive and non-impulsive. Impulsive sounds (e.g., explosions, sonic
booms, impact pile driving) are typically transient, brief (less than 1
second), broadband, and consist of high peak sound pressure with rapid
rise time and rapid decay (ANSI, 1986; NIOSH, 1998; NMFS, 2018). Non-
impulsive sounds (e.g., machinery operations such as drilling or
dredging, vibratory pile driving, underwater chainsaws, and active
sonar systems) can be broadband, narrowband or tonal, brief or
prolonged (continuous or intermittent), and typically do not have the
high peak sound pressure with raid rise/decay time that impulsive
sounds do (ANSI, 1995; NIOSH, 1998; NMFS, 2018). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997).
Two types of hammers would be used on this project, impact and
vibratory. Impact hammers operate by repeatedly dropping and/or pushing
a heavy piston onto a pile to drive the pile into the substrate. Sound
generated by impact hammers is considered impulsive. Vibratory hammers
install piles by vibrating them and allowing the weight of the hammer
to push them into the sediment. Vibratory hammers produce non-
impulsive, continuous sounds. Vibratory hammering generally produces
SPLs 10 to 20 dB lower than impact pile driving of the same-sized pile
(Oestman et al., 2009). Rise time is slower, reducing the probability
and severity of injury, and sound energy is distributed over a greater
amount of time (Nedwell and Edwards, 2002; Carlson et al., 2005).
The likely or possible impacts of Chevron's proposed activities on
marine mammals could be generated from both non-acoustic and acoustic
stressors. Potential non-acoustic stressors include the physical
presence of the equipment, vessels, and personnel; however, we expect
that any animals that approach the project site close enough to be
harassed due to the presence of equipment or personnel would be within
the Level B harassment zones from pile driving and would already be
subject to harassment from the in-water activities. Therefore, any
impacts to marine mammals are expected to primarily be acoustic in
nature.
[[Page 19255]]
Acoustic stressors are generated by heavy equipment operation during
pile driving activities (i.e., impact and vibratory pile driving and
removal).
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving equipment is the primary means by which
marine mammals may be harassed from Chevron's specified activities. In
general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007). Generally, exposure to
pile driving and removal and other construction noise has the potential
to result in auditory threshold shifts and behavioral reactions (e.g.,
avoidance, temporary cessation of foraging and vocalizing, changes in
dive behavior). Exposure to anthropogenic noise can also lead to non-
observable physiological responses, such as an increase in stress
hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions, such
as communication and predator and prey detection. The effects of pile
driving and demolition noise on marine mammals are dependent on several
factors, including, but not limited to, sound type (e.g., impulsive vs.
non-impulsive), the species, age and sex class (e.g., adult male vs.
mother with calf), duration of exposure, the distance between the pile
and the animal, received levels, behavior at time of exposure, and
previous history with exposure (Wartzok et al., 2004; Southall et al.,
2007). Here we discuss physical auditory effects (threshold shifts)
followed by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (2018), there are numerous factors
to consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how animal uses sound within the
frequency band of the signal; e.g., Kastelein et al., 2014a), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40 dB
threshold shift approximates PTS onset (see Ward et al., 1958, 1959;
Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996;
Henderson et al., 2008). PTS levels for marine mammals are estimates,
because there are limited empirical data measuring PTS in marine
mammals (e.g., Kastak et al., 2008), largely due to the fact that, for
various ethical reasons, experiments involving anthropogenic noise
exposure at levels inducing PTS are not typically pursued or authorized
(NMFS, 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2018). Based on data from cetacean TTS
measurements (see Southall et al., 2007), a TTS of 6 dB is considered
the minimum threshold shift clearly larger than any day-to-day or
session-to-session variation in a subject's normal hearing ability
(Schlundt et al., 2000; Finneran et al., 2000, 2002). As described in
Finneran (2016), marine mammal studies have shown the amount of TTS
increases with cumulative sound exposure level (SEL<INF>cum</INF>) in
an accelerating fashion: At low exposures with lower SEL<INF>cum,</INF>
the amount of TTS is typically small and the growth curves have shallow
slopes. At exposures with higher SEL<INF>cum</INF>, the growth curves
become steeper and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis),
and five species of pinnipeds exposed to a limited number of sound
sources (i.e., mostly tones and octave-band noise) in laboratory
settings (Finneran, 2015). TTS was not observed in trained spotted
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive
noise at levels matching previous predictions of TTS onset (Reichmuth
et al., 2016). In general, harbor seals and harbor porpoises have a
lower TTS onset than other measured pinniped or cetacean species
(Finneran, 2015). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a, 2019b, 2020a, 2020b). In addition, TTS
can accumulate across multiple exposures, but the resulting TTS will be
less than the TTS from a single, continuous exposure with the same SEL
(Finneran et al., 2010; Kastelein et al., 2014b; Kastelein et al.,
2015a; Mooney et al., 2009). This means that TTS predictions based on
the total, cumulative SEL will overestimate the amount of TTS from
intermittent exposures such as sonars and impulsive sources.
The potential for TTS from impact pile driving exists. After
exposure to playbacks of impact pile driving sounds (rate 2,760
strikes/hour) in captivity, mean TTS increased from 0 dB after 15
minute exposure to 5 dB after 360 minute exposure; recovery occurred
within 60 minutes (Kastelein et al., 2016). Additionally, the existing
marine mammal TTS data come from a limited number of individuals within
these species. No data are available on noise-induced hearing loss for
mysticetes. Nonetheless, what we considered is the best available
science. For summaries of data on TTS in marine mammals or for
[[Page 19256]]
further discussion of TTS onset thresholds, please see Southall et al.
(2007, 2019), Finneran and Jenkins (2012), Finneran (2015), and table 5
in NMFS (2018).
Activities for this project include impact and vibratory pile
driving, and vibratory pile removal. There would likely be pauses in
activities producing the sound during each day. Given these pauses and
the fact that many marine mammals are likely moving through the project
areas and not remaining for extended periods of time, the potential for
TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
removal also has the potential to behaviorally disturb marine mammals.
Available studies show wide variation in response to underwater sound;
therefore, it is difficult to predict specifically how any given sound
in a particular instance might affect marine mammals perceiving the
signal. If a marine mammal does react briefly to an underwater sound by
changing its behavior or moving a small distance, the impacts of the
change are unlikely to be significant to the individual, let alone the
stock or population. However, if a sound source displaces marine
mammals from an important feeding or breeding area for a prolonged
period, impacts on individuals and populations could be significant
(e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 2005).
Disturbance may result in changing durations of surfacing and
dives, number of blows per surfacing, or moving direction and/or speed;
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior (such as tail/fluke slapping or jaw
clapping); or avoidance of areas where sound sources are located.
Pinnipeds may increase their haul-out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound
are highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al.,
2007; Weilgart, 2007; Archer et al., 2010; Southall et al., 2021).
Behavioral reactions can vary not only among individuals but also
within an individual, depending on previous experience with a sound
source, context, and numerous other factors (Ellison et al., 2012), and
can vary depending on characteristics associated with the sound source
(e.g., whether it is moving or stationary, number of sources, distance
from the source). In general, pinnipeds seem more tolerant of, or at
least habituate more quickly to, potentially disturbing underwater
sound than do cetaceans, and generally seem to be less responsive to
exposure to industrial sound than most cetaceans. Please see Appendices
B and C of Southall et al. (2007) as well as Nowacek et al. (2007);
Ellison et al. (2012), and Gomez et al. (2016) for a review of studies
involving marine mammal behavioral responses to sound.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 2007;
Melc[oacute]n et al., 2012). In addition, behavioral state of the
animal plays a role in the type and severity of a behavioral response,
such as disruption to foraging (e.g., Sivle et al., 2016; Wensveen et
al., 2017). A determination of whether foraging disruptions incur
fitness consequences would require information on or estimates of the
energetic requirements of the affected individuals and the relationship
between prey availability, foraging effort and success, and the life
history stage of the animal (Goldbogen et al., 2013).
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker 2000; Romano
et al., 2002b) and, more rarely, studied in wild populations (e.g.,
Romano et al., 2002a). For example, Rolland et al. (2012) found that
noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003), however
distress is an unlikely result of these projects based on observations
of marine mammals during previous, similar projects in the area.
Masking--Sound can disrupt behavior through masking, or interfering
with, an animal's ability to detect, recognize, or discriminate between
acoustic signals of
[[Page 19257]]
interest (e.g., those used for intraspecific communication and social
interactions, prey detection, predator avoidance, navigation)
(Richardson et al., 1995). Masking occurs when the receipt of a sound
is interfered with by another coincident sound at similar frequencies
and at similar or higher intensity, and may occur whether the sound is
natural (e.g., snapping shrimp, wind, waves, precipitation) or
anthropogenic (e.g., pile driving, shipping, sonar, seismic
exploration) in origin. The ability of a noise source to mask
biologically important sounds depends on the characteristics of both
the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions. Masking of natural sounds can result when human activities
produce high levels of background sound at frequencies important to
marine mammals. Conversely, if the background level of underwater sound
is high (e.g., on a day with strong wind and high waves), an
anthropogenic sound source would not be detectable as far away as would
be possible under quieter conditions and would itself be masked. The
masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt
et al., 2009). The Bay is heavily used by commercial, recreational, and
military vessels, and background sound levels in the area are already
elevated. Due to the transient nature of marine mammals to move and
avoid disturbance, masking is not likely to have long-term impacts on
marine mammal species within the proposed project area.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and removal that have the potential to cause behavioral harassment,
depending on their distance from pile driving activities. Cetaceans are
not expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the acoustic criteria. We recognize that
pinnipeds in the water could be exposed to airborne sound that may
result in behavioral harassment when looking with their heads above
water. Most likely, airborne sound would cause behavioral responses
similar to those discussed above in relation to underwater sound. For
instance, anthropogenic sound could cause hauled-out pinnipeds to
exhibit changes in their normal behavior, such as reduction in
vocalizations, or cause them to temporarily abandon the area and move
further from the source. However, these animals would likely previously
have been ``taken'' because of exposure to underwater sound above the
behavioral harassment thresholds, which are generally larger than those
associated with airborne sound. Thus, the behavioral harassment of
these animals is already accounted for in these estimates of potential
take. Therefore, we do not believe that authorization of incidental
take resulting from airborne sound for pinnipeds is warranted, and
airborne sound is not discussed further here.
Marine Mammal Habitat Effects
Chevron's proposed construction activities could have localized,
temporary impacts on marine mammal habitat, including prey, by
increasing in-water sound pressure levels and slightly decreasing water
quality. Increased noise levels may affect acoustic habitat (see
masking discussion above) and adversely affect marine mammal prey in
the vicinity of the project areas (see discussion below). During impact
and vibratory pile driving or removal, elevated levels of underwater
noise would ensonify the project area where both fishes and mammals
occur, and could affect foraging success. Additionally, marine mammals
may avoid the area during construction, however, displacement due to
noise is expected to be temporary and is not expected to result in
long-term effects to the individuals or populations. Construction
activities are expected to be of short duration and would likely have
temporary impacts on marine mammal habitat through increases in
underwater and airborne sound.
A temporary and localized increase in turbidity near the seafloor
would occur in the immediate area surrounding the area where piles are
installed or removed. In general, turbidity associated with pile
driving is localized to about a 25-ft (7.6-m) radius around the pile
(Everitt et al., 1980). Cetaceans are not expected to be close enough
to the pile driving areas to experience effects of turbidity, and any
pinnipeds could avoid localized areas of turbidity. Local currents are
anticipated to disburse any additional suspended sediments produced by
project activities at moderate to rapid rates depending on tidal stage.
Therefore, we expect the impact from increased turbidity levels to be
discountable to marine mammals and do not discuss it further.
In-Water Construction Effects on Potential Foraging Habitat--The
area likely impacted by the LWMEP is relatively small compared to the
total available habitat in the Bay. The proposed project area is highly
influenced by anthropogenic activities and provides limited foraging
habitat for marine mammals. Furthermore, pile driving and removal at
the proposed project site would not obstruct long-term movements or
migration of marine mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. The
duration of fish and marine mammal avoidance of this area after pile
driving stops is unknown, but a rapid return to normal recruitment,
distribution, and behavior is anticipated. Any behavioral avoidance by
prey of the disturbed area would still leave significantly large areas
of potential foraging habitat in the nearby vicinity.
In-water Construction Effects on Potential Prey--Sound may affect
marine mammals through impacts on the abundance, behavior, or
distribution of prey species (e.g., crustaceans, cephalopods, fish,
zooplankton, other marine mammals). Marine mammal prey varies by
species, season, and location. Here, we describe studies regarding the
effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay,
2009). Depending on their hearing anatomy and peripheral sensory
structures, which vary among species, fishes hear sounds using pressure
and particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage,
[[Page 19258]]
barotrauma (pressure-related injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish; several are based on
studies in support of large, multiyear bridge construction projects
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Many
studies have demonstrated that impulse sounds might affect the
distribution and behavior of some fishes, potentially impacting
foraging opportunities or increasing energetic costs (e.g., Fewtrell
and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992;
Santulli et al., 1999; Paxton et al., 2017). In response to pile
driving, Pacific sardines and northern anchovies may exhibit an
immediate startle response to individual strikes, but return to
``normal'' pre[hyphen]strike behavior following the conclusion of pile
driving with no evidence of injury as a result (appendix C in NAVFAC
SW, 2014). However, some studies have shown no or slight reaction to
impulse sounds (e.g., Pena et al., 2013; Wardle et al., 2001; Jorgenson
and Gyselman, 2009; Popper et al., 2005).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fishes from pile driving and removal and
construction activities at the project area would be temporary
behavioral avoidance of the area. The duration of fish avoidance of
this area after pile driving stops is unknown, but a rapid return to
normal recruitment, distribution, and behavior is anticipated. In
general, impacts to marine mammal prey species are expected to be minor
and temporary. Further, it is anticipated that preparation activities
for pile driving or removal (i.e., positioning of the hammer, clipper
or wire saw) and upon initial startup of devices would cause fish to
move away from the affected area outside areas where injuries may
occur. Therefore, relatively small portions of the proposed project
area would be affected for short periods of time, and the potential for
effects on fish to occur would be temporary and limited to the duration
of sound[hyphen]generating activities.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed actions
are not likely to have a permanent, adverse effect on any fish habitat,
or populations of fish species. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large potential areas
fish and marine mammal foraging habitat in the nearby vicinity. Thus,
we conclude that impacts of the specified activities are not likely to
have more than short-term adverse effects on any prey habitat or
populations of prey species. Further, any impacts to marine mammal
habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to adverse
impacts on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of disruption of behavioral patterns for individual marine mammals
resulting from exposure to the acoustic sources. Based on the nature of
the activity and the anticipated effectiveness of the mitigation
measures (i.e., shutdown zones, PSO monitoring) discussed in detail
below in the Proposed Mitigation section, Level A harassment is neither
anticipated nor proposed to be authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
[[Page 19259]]
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
Chevron's proposed construction activities include the use of
continuous (vibratory pile-driving) and impulsive (impact pile-driving)
sources, and therefore the RMS SPL thresholds of 120 and 160 dB re 1
[mu]Pa are applicable.
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise from
two different types of sources (impulsive or non-impulsive). Chevron's
proposed construction activities include the use of impulsive (impact
hammer) and non-impulsive (vibratory hammer) sources.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset thresholds * (received level)
Hearing group --------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans......... Cell 1: Lp,0-pk,flat: Cell 2: LE,p, LF,24h: 199 dB.
219 dB; LE,p,LF,24h:
183 dB.
Mid-Frequency (MF) Cetaceans......... Cell 3: Lp,0-pk,flat: Cell 4: LE,p,MF,24h: 198 dB.
230 dB; LE,p,MF,24h:
185 dB.
High-Frequency (HF) Cetaceans........ Cell 5: Lp,0-pk,flat: Cell 6: LE,p,HF,24h: 173 dB.
202 dB; LE,p,HF,24h:
155 dB.
Phocid Pinnipeds (PW) (Underwater)... Cell 7: Lp,0-pk.flat: Cell 8: LE,p,PW,24h: 201 dB.
218 dB; LE,p,PW,24h:
185 dB.
Otariid Pinnipeds (OW) (Underwater).. Cell 9: Lp,0-pk,flat: Cell 10: LE,p,OW,24h: 219 dB.
232 dB; LE,p,OW,24h:
203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS
onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds
associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
hearing range of marine mammals (i.e., 7 Hz to 160 kHz). The subscript associated with cumulative sound
exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF
cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted
cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e., varying exposure
levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the
conditions under which these thresholds will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
Pile driving activities, using an impact hammer as well as a
vibratory hammer, would generate underwater noise that could result in
disturbance to marine mammals near the project area. A review of
underwater sound measurements for similar projects was conducted to
estimate the near-source sound levels for impact and vibratory pile
driving and vibratory extraction. Source levels for proposed removal
and installation activities derived from this review are shown in table
5.
Table 5--Source Levels for Proposed Pile Removal and Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source levels (dB)/source distance (m)
-----------------------------------------------------
Method Pile type Peak sound Mean maximum Reference
pressure (dB RMS SPL (dB re SEL (dB re 1
re 1 [mu]Pa) 1 [mu]Pa) [mu]Pa2 sec)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact install \1\....................... 24-inch square concrete 191/10 173/10 161/10 AECOM (2018, 2019).
pile.
Vibratory install/extract................ 36-inch steel shell pile... 196/10 167/15 167 AECOM (2019).
Vibratory extract \2\.................... 18-inch concrete pile...... N/A 163/10 150 NAVFAC SW (2022).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Chevron would use a bubble curtain attenuation system for all impact pile driving. NMFS conservatively assumes that the bubble curtain would result
in a 5 dB reduction in sound. These source levels incorporate the 5 dB reduction.
\2\ 20-inch concrete piles used as a proxy as vibratory data for 18-inch concrete piles was not available.
[[Page 19260]]
Level B Harassment Zones--Transmission loss (TL) is the decrease in
acoustic intensity as an acoustic pressure wave propagates out from a
source. TL parameters vary with frequency, temperature, sea conditions,
current, source and receiver depth, water depth, water chemistry, and
bottom composition topography. The general formula for underwater TL
is:
TL = B * Log10 (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.
The recommended TL coefficient for most nearshore environments is
the practical spreading value of 15. This value results in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions, known as practical spreading. As
is common practice in coastal waters, here we assume practical
spreading (4.5 dB reduction in sound level for each doubling of
distance) for vibratory extraction of concrete piles, as hydro-acoustic
data for the same pile type was not available for this project site.
Chevron conducted hydro-acoustic monitoring for prior projects at Long
Wharf for the impact driving of 24-inch concrete piles and vibratory
driving of 36-inch steel piles. Based upon hydro-acoustic monitoring
conducted at Long Wharf in 2018 and 2019 (AECOM 2018, 2019), Chevron
calculated a transmission loss coefficient ranging from 14 to 20 (~4.4
dB to 8 dB per doubling of distance). As this estimate represents a
wide range of measured transmission loss, NMFS applied the standard
value of 15 for impact driving of concrete piles. For vibratory driving
of 36-inch steel piles, Chevron calculated a transmission loss
coefficient of 20.8 to 25.0 (~8 dB to 9 dB per doubling of distance)
from hydro-acoustic monitoring conducted at Long Wharf in 2019 (AECOM,
2019). Given that all available data suggested a higher transmission
loss, NMFS found it appropriate to apply this to its analysis. NMFS
applied the lower of these two values, 20.8 TL, to this analysis to be
conservative. The Level B harassment zones and ensonified areas for
Chevron's proposed activities are shown in table 6.
Table 6--Distance to Level B Harassment Thresholds and Ensonified Areas
----------------------------------------------------------------------------------------------------------------
Source levels (dB)/ source Distance to
distance (m) Level B Ensonified
Pile type -------------------------------- harassment area (km\2\)
Peak RMS thresholds (m)
----------------------------------------------------------------------------------------------------------------
Impact Installation:
24-inch square concrete pile................ 191/10 173/10 74 0.02
Vibratory Installation:
36-inch steel shell pile.................... 196/10 167/15 2,727 23.36
Vibratory Extraction:
18-inch concrete pile....................... N/A 163/10 7,356 170
36-inch steel shell pile.................... 196/10 167/15 2,727 17.24
----------------------------------------------------------------------------------------------------------------
Level A Harassment Thresholds--The ensonified area associated with
Level A harassment is more technically challenging to predict due to
the need to account for a duration component. Therefore, NMFS developed
an optional User Spreadsheet tool to accompany the Technical Guidance
that can be used to relatively simply predict an isopleth distance for
use in conjunction with marine mammal density or occurrence to help
predict potential takes. We note that because of some of the
assumptions included in the methods underlying the optional tool, we
anticipate that the resulting isopleth estimates are typically going to
be overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources, such as pile driving activities, the optional User
Spreadsheet tool predicts the closest distance at which a stationary
animal would not be expected to incur PTS if the sound source traveled
by the stationary animal in a straight line at a constant speed. The
isopleths generated by the User Spreadsheet used the same TL
coefficients as the Level B harassment zone calculations, as indicated
above for each activity type. Inputs used in the User Spreadsheet
(e.g., number of piles per day, duration and/or strikes per pile) are
presented in table 1. The maximum RMS SPL/SEL SPL as well as peak SPL
and resulting isopleths are reported below in table 7. The RMS SPL
value was used to calculate Level A harassment isopleths for vibratory
pile driving and extraction activities, while the single strike SEL SPL
value was used to calculate Level A isopleths for impact pile driving
activity.
Table 7--Distance to Level A Harassment Thresholds for Each Marine Mammal Hearing Group
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source levels (dB)/ source distance (m) Distances to Level A harassment threshold (m)
--------------------------------------------------------------------------------------------------------------
Pile type Lf Mf Hf Phocid Otariid
Peak RMS/SEL cetaceans cetaceans cetaceans pinnipeds pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation:
24-inch square concrete pile......... 191/10 161/10 SEL..................... 31.3 1.1 37.3 16.8 1.2
Vibratory Installation:
36-inch steel shell pile............. 196/10 167/15 RMS..................... 15.9 2.8 21 11.1 1.6
Vibratory Extraction:
18-inch concrete pile................ N/A 163/10 RMS..................... 3.4 0.3 5 2.1 0.1
[[Page 19261]]
36-inch steel shell pile............. 196/10 167/15 RMS..................... 15.9 2.8 21 11.1 1.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Lf = low frequency, Mf = mid-frequency, Hf = high frequency.
Marine Mammal Occurrence
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information, that
will inform the take calculations.
Harbor seal--Limited at-sea densities are available for Pacific
harbor seals in the Bay. To estimate the number of harbor seals
potentially taken by Level B harassment, take estimates were developed
based upon annual surveys of haul outs in the Bay conducted by the
National Park Service (NPS) (Codde and Allen 2013, 2015, 2017, 2020;
Codde, 2020). Harbor seals spend more time hauled out and enter the
water later in the evening during molting season (NPS, 2014). The
molting season occurs from June-July and overlaps with the construction
period of June-November, therefore, haul out counts may provide the
most accurate estimates of harbor seals in the area during that time.
Due to the close proximity of Castro Rocks to the project area, Chevron
used the highest mean value of harbor seals observed hauled out at
Castro Rocks during the molting season in any recent NPS annual survey.
The highest mean number of harbor seals was recorded in 2019 as 237
seals. There are no systematic counts available to estimate the number
of seals that may be in the water near Long Wharf at any given time and
the number of seals hauled out on Castro Rocks may vary based upon time
of day, tide, and seal activity. Therefore, the analysis assumes that
all 237 seals could swim into the Level B harassment zone each day that
pile driving is occurring.
California sea lion--Although there are no haul out sites for
California sea lions in close proximity to the project area, sea lions
have consistently been sighted in the Bay while monitoring during past
construction projects (AECOM 2019, 2020, 2021, 2022; Caltrans, 2017).
As limited data is available on the occurrences of California sea lions
in the Bay, NMFS used PSO monitoring data from previous stages of the
LWMEP (AECOM, 2019, 2020, 2021) and Year 1 of the Point Orient Wharf
Removal (POWR) project (AECOM, 2022) to generate a daily occurrence
rate. NMFS calculated daily occurrence rate using the following
equation:
Daily occurrence rate = Total number of animals sighted/Total
monitoring days
From 2018-2022, a total of 73 days of monitoring occurred across
all projects during the seasonal window of June through November.
During this time, 13 sea lions were sighted. Based upon sightings and
monitoring days, we calculated a daily occurrence rate of 0.18 sea
lions per day.
San Francisco has received a record amount of rainfall since July
1, 2022 (Bay City News, 2023), indicating that increased freshwater
inflow into the Bay could be expected this year. The Bay did not
experience similar freshwater inflow during the LWMEP and POWR years of
2018-2022. As the impacts of increased freshwater flow into the project
area on California sea lion occurrences are unclear, and this increased
freshwater input did not occur during prior monitoring years, we
conservatively used a daily occurrence rate of California sea lions, 1
sea lion per day, to estimate take.
Harbor porpoise--The harbor porpoise population has been growing
over time in the Bay (Stern et al., 2017). Although commonly sighted in
the vicinity of Angel Island and the Golden Gate Bridge, approximately
6 and 12 kilometers (3.7 and 7.5 miles, respectively) southwest of the
Wharf, individuals may use other areas of central the Bay (Keener,
2011), as well as the project area. As limited data is available on the
occurrences of harbor porpoises in the Bay, NMFS used PSO monitoring
data from previous stages of the LWMEP (AECOM, 2019, 2020, 2021) and
Year 1 of the Point Orient Wharf Removal (POWR) project (AECOM, 2022)
to generate a daily occurrence rate. NMFS calculated the daily
occurrence rate according to the same methods for calculating the daily
occurrence rate for California sea lions, as described above. From
2018-2022, a total of 16 harbor porpoises were sighted on 73 monitoring
days, resulting in a daily occurrence rate of 0.22 harbor porpoises per
day. Due to the impacts of increased freshwater inflow into the Bay
(Bay City News, 2023) resulting from elevated rainfall being unclear,
we conservatively used a higher daily occurrence rate of harbor
porpoises, 1 porpoise per day, to estimate take.
Gray whale--Gray whales are often sighted in the Bay during
February and March, however, pile driving activities are not planned to
occur during this time. Prior monitoring reports for similar projects
occurring during the same work windows did not document gray whales in
the area (AECOM 2019, 2020, 2021). Limited sightings of gray whales in
the Bay include strandings (Bartlett 2022; TMMC, 2019) and whale watch
reports (Bartlett, 2022). At-sea densities and regular observational
data for gray whales in the Bay during the planned project time are not
available. Although unlikely during the time planned for in-water
construction activities, Chevron conservatively estimated that up to
two gray whales may occur in the project area.
Bottlenose dolphin--The numbers of dolphins in the Bay have been
increasing over the years (Perlman, 2017; Szczepaniak et al., 2013),
and a recent study determined that bottlenose dolphins have expanded
their range to include coastal waters north and south of the Bay
(Keener et al., 2023). In the Bay, dolphins have been sighted in the
vicinity of the Golden Gate Bridge, around Yerba Buena and Angel
Islands, and in the central Bay as far east as Alameda and Point
Richard (Keener et al., 2023). Although dolphins may occur in the Bay
year-round, occurrence estimates are limited. Chevron estimated that
one group of dolphins may enter the Bay once per month. Weller et al.
(2016) estimated an average group size for coastal bottlenose dolphins
to be approximately 8.2 dolphins.
Northern elephant seal--Small numbers of elephant seals may haul
out or strand within the central Bay (Hern[aacute]ndez, 2020). Previous
monitoring, however, has shown northern elephant seal densities to be
very low in the area and, based upon seasonality of occurrences,
northern elephant seals would be unlikely to occur in the
[[Page 19262]]
project area during the proposed project activities. Additionally,
northern elephant seals were not observed during pile driving
monitoring for the LWMEP from 2018-2021 (AECOM, 2018, 2019, 2020, 2021)
nor for the Point Orient Wharf Removal in 2022 (AECOM, 2022), which was
located just north of the proposed project area. While it is unlikely
that northern elephant seals would occur in the project area during the
months in which work is proposed, Chevron conservatively estimated that
one northern elephant seal could enter the project area once every 3
days during in-water construction activities resulting in a total of 10
northern elephant seals.
Northern fur seal--The presence of northern fur seals in depends
upon oceanic conditions, as more fur seals are more likely to range in
the Bay in search of food and strand during El Ni[ntilde]o events
(TMMC, 2016). Equatorial sea surface temperatures of the Pacific Ocean
have been below average across most of the Pacific. La Ni[ntilde]a
conditions are likely to remain into the spring 2023 after which
conditions are expected to become more neutral. However, it is unlikely
El Ni[ntilde]o conditions would develop later in 2023 (NOAA, 2022).
Northern fur seals were not observed during prior LWMEP monitoring
(AECOM, 2019, 2020, 2021) nor during the POWRP monitoring (AECOM,
2022). While it is unlikely that northern fur seals would occur in the
project areas during in-water activities, Chevron conservatively
estimated that a maximum of 10 northern fur seals could occur enter the
project area.
Take Estimation
Here we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization.
Take estimate calculations vary by species. To calculate take by
Level B harassment for harbor seals, California sea lions, and harbor
porpoises, NMFS multiplied the daily occurrence estimates described in
the Marine Mammal Occurrence section by the number of project days
(table 8).
For bottlenose dolphins, Chevron estimated, and NMFS concurs, that
one group of 8 bottlenose dolphins may be taken by Level B harassment
every month of the project. Therefore, Chevron requested, and NMFS
proposes to authorize, 32 takes of bottlenose dolphins by Level B
harassment.
Chevron based requested take by Level B harassment for gray whales
upon total daily occurrence estimates during the project period.
Chevron conservatively estimated, and NMFS concurs, that 2 gray whales
may enter the project area per year. Therefore, Chevron requested, and
NMFS proposes to authorize, 2 takes of gray whales by Level B
harassment (table 8).
For northern elephant seals, Chevron conservatively estimated, and
NMFS concurs, that one northern elephant seal could enter the project
area once every 3 days during in-water construction activities.
Therefore, Chevron requested, and NMFS proposes to authorize, 10 takes
of northern elephant seals by Level B harassment (table 8).
Based upon prior occurrences in the Bay, Chevron conservatively
estimated, and NMFS concurs, that a maximum of 10 northern fur seals
could occur in the project area during the in-water construction
activity period. Therefore, Chevron requested, and NMFS proposes to
authorize 10 takes of northern fur seals by Level B harassment (table
8).
Chevron did not request, nor is NMFS proposing to authorize, take
by Level A harassment. For all pile driving activities, Chevron
proposed to implement shutdown zones (described further in the Proposed
Mitigation section) that would be expected to effectively prevent take
by Level A harassment.
Table 8--Estimated Take by Level B Harassment Proposed for Authorization and Estimated Take as a Percentage of
the Population
----------------------------------------------------------------------------------------------------------------
Estimated take by Level B harassment
proposed for authorization Estimated take
Species Expected -------------------------------------------- as a percentage
occurrence Impact Vibratory of population
install install/extract Total
----------------------------------------------------------------------------------------------------------------
Harbor seal.................... 237 seals per day 4,977 2,133 7,110 23
Sea lion....................... 1 sea lion per 21 9 30 0.012
day \1\.
Harbor porpoise................ 1 harbor porpoise 21 9 30 0.39
per day \1\.
Bottlenose dolphin............. Up to 8 dolphins N/A N/A 32 1.77
once per month.
Gray whale..................... 2 whales over N/A N/A 2 0.007
project duration.
Northern elephant seal......... 1 seal every 3 N/A N/A 10 0.005
days.
Northern fur seal.............. 10 seals over N/A N/A 10 0.071
project duration.
----------------------------------------------------------------------------------------------------------------
\1\ Rounded daily occurrence to one individual per day.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure would be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned), and;
[[Page 19263]]
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
Chevron must follow mitigation measures as specified below.
Chevron must ensure that construction supervisors and crews, the
monitoring team, and relevant Chevron staff are trained prior to the
start of all pile driving activities, so that responsibilities,
communication procedures, monitoring protocols, and operational
procedures are clearly understood. New personnel joining during the
project must be trained prior to commencing work.
Shutdown Zones
Chevron must establish shutdown zones for all pile driving
activities. The purpose of a shutdown zone is generally to define an
area within which shutdown of the activity would occur upon sighting of
a marine mammal (or in anticipation of an animal entering the defined
area). Shutdown zones would be based upon the Level A harassment zone
for each pile size/type and driving method where applicable, as shown
in table 7. A minimum shutdown zone of 10 m would be required for all
in-water construction activities to avoid physical interaction with
marine mammals. For pile driving, the radii of the shutdown zones are
rounded to the next largest 10 m interval in comparison to the Level A
harassment zone for each activity type. If a marine mammal is observed
entering or within a shutdown zone during pile driving activity, the
activity must be stopped until there is visual confirmation that the
animal has left the zone or the animal is not sighted for a period of
15 minutes. Proposed shutdown zones for each activity type are shown in
table 9.
All marine mammals would be monitored in the Level B harassment
zones and throughout the area as far as visual monitoring can take
place. If a marine mammal enters the Level B harassment zone, in-water
activities would continue and PSOs would document the animal's presence
within the estimated harassment zone.
Chevron would also establish shutdown zones for all marine mammals
for which take has not been authorized or for which incidental take has
been authorized but the authorized number of takes has been met. These
zones would be equivalent to the Level B harassment zones for each
activity. If a marine mammal species for which take is not authorized
or a species for which incidental take has been authorized but the
authorized number of takes has been met enters the shutdown zone, all
in-water activities would cease until the animal leaves the zone or has
not been observed for at least 1 hour, and NMFS would be notified about
species and precautions taken. Pile removal would proceed if the animal
is observed to leave the Level B harassment zone or if 1 hour has
passed since the last observation.
If shutdown and/or clearance procedures would result in an imminent
safety concern, as determined by Chevron or its designated officials,
the in-water activity would be allowed to continue until the safety
concern has been addressed, and the animal would be continuously
monitored.
Table 9--Proposed Shutdown Zones by Activity Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown zones (m) \1\
Method Pile type -------------------------------------------------------------------------------
LF MF HF PW OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile removal activities:
Vibratory extract.................. 36-inch steel pile............. 20 10 30 20 10
18-inch concrete pile.......... 10 10 10 10 10
Pile installation activities:
Impact install..................... 24-inch square concrete pile... 40 10 40 20 10
Vibratory install.................. 36-inch steel pile............. 20 10 30 20 10
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Observers would monitor as far as the eye can see.
Protected Species Observers
The placement of PSOs during all pile driving activities (described
in the Proposed Monitoring and Reporting section) would ensure that the
entire shutdown zone is visible. Should environmental conditions
deteriorate such that the entire shutdown zone would not be visible
(e.g., fog, heavy rain), pile driving would be delayed until the PSO is
confident marine mammals within the shutdown zone could be detected.
PSOs would monitor the full shutdown zones and the Level B
harassment zones to the extent practicable. Monitoring zones provide
utility for observing by establishing monitoring protocols for areas
adjacent to the shutdown zones. Monitoring zones enable observers to be
aware of and communicate the presence of marine mammals in the project
areas outside the shutdown zones and thus prepare for a potential
cessation of activity should the animal enter the shutdown zone.
Pre- and Post-Activity Monitoring
Monitoring must take place from 30 minutes prior to initiation of
pile driving activities (i.e., pre-clearance monitoring) through 30
minutes post-completion of pile driving. Prior to the start of daily
in-water construction activity, or whenever a break in pile driving of
30 minutes or longer occurs, PSOs would observe the shutdown and
monitoring zones for a period of 30 minutes. The shutdown zone would be
considered cleared when a marine mammal has not been observed within
the zone for a 30-minute period. If a marine mammal is observed within
the shutdown zones listed in table 10, pile driving activity would be
delayed or halted. If work ceases for more than 30 minutes, the pre-
activity monitoring of the shutdown zones would commence. A
determination that the shutdown zone is clear must be made during a
period of good visibility (i.e., the entire shutdown zone and
surrounding waters must be visible to the naked eye).
Soft-Start Procedures
Soft-start procedures provide additional protection to marine
mammals by providing warning and/or giving marine mammals a chance to
leave the area prior to the hammer operating at full capacity. For
impact pile driving, contractors would be required to provide an
initial set of three strikes from the hammer at reduced energy,
followed by a 30-second waiting period, then two subsequent reduced-
energy strike sets. Soft-start would be implemented at the start of
each day's
[[Page 19264]]
impact pile driving and at any time following cessation of impact pile
driving for a period of 30 minutes or longer.
Bubble Curtain
A bubble curtain must be employed during all impact pile
installation of the 24-inch square concrete piles to interrupt the
acoustic pressure and reduce impact on marine mammals. The bubble
curtain must distribute air bubbles around 100 percent of the piling
circumference for the full depth of the water column. The lowest bubble
ring must be in contact with the mudline for the full circumference of
the ring. The weights attached to the bottom ring must ensure 100
percent substrate contact. No parts of the ring or other objects may
prevent full substrate contact. Air flow to the bubblers must be
balanced around the circumference of the pile.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that would result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<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.
Visual Monitoring
Marine mammal monitoring must be conducted in accordance with the
conditions in this section, the Monitoring Plan, and this IHA. Marine
mammal monitoring during pile driving activities would be conducted by
PSO's meeting NMFS' standards and in a manner consistent with the
following:
<bullet> PSOs must be independent of the activity contractor (for
example, 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 incidental take authorization;
<bullet> Other PSOs may substitute other relevant experience,
education (degree in biological science or related field), or training
for prior experience performing the duties of a PSO during construction
activity pursuant to a NMFS-issued incidental take authorization;
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator must be designated. The lead
observer must have prior experience performing the duties of a PSO
during construction activity pursuant to a NMFS-issued incidental take
authorization; and
<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 behaviors;
<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 provide real-time information on marine mammals
observed in the area as necessary.
Chevron would have at least two PSOs stationed at the best possible
vantage points in the project area to monitor during all pile driving
activities. Monitoring would occur from elevated locations along the
shoreline or on barges where the entire shutdown zones and monitoring
zones are visible. PSOs would be equipped with high quality binoculars
for monitoring and radios or cells phones for maintaining contact with
work crews. Monitoring would be conducted 30 minutes before, during,
and 30 minutes after all in water construction activities. In addition,
PSOs would record all incidents of marine mammal occurrence, regardless
of distance from activity, and would document any behavioral reactions
in concert with distance from piles being driven or removed. Pile
driving activities include the time to install or remove a single pile
or series of piles, as long as the time elapsed between uses of the
pile driving equipment is no more than 30 minutes.
In addition to monitoring on days that construction would occur, as
proposed by the applicant, Chevron would conduct biological monitoring
within one week ahead of the project's start date to establish baseline
observation. These observation periods would encompass different tide
levels at different hours of the day.
Data Collection
Chevron would record detailed information about implementation of
shutdowns, counts and behaviors (if possible) of all marine mammal
species observed, times of observations, construction activities that
occurred, any acoustic and visual disturbances, and weather conditions.
PSOs would
[[Page 19265]]
use approved data forms to record the following information:
<bullet> Date and time that permitted construction activity begins
and ends;
<bullet> Type of pile removal activities that take place;
<bullet> Weather parameters (e.g., percent cloud cover, percent
glare, visibility, air temperature, tide level, Beaufort sea state);
<bullet> Species counts, and, if possible, sex and age classes of
any observed marine mammal species;
<bullet> Marine mammal behavior patterns, including bearing and
direction of travel;
<bullet> Any observed behavioral reactions just prior to, during,
or after construction activities;
<bullet> Location of marine mammal, distance from observer to the
marine mammal, and distance from pile driving activities to marine
mammals;
<bullet> Whether an observation required the implementation of
mitigation measures, including shutdown procedures and the duration of
each shutdown; and
<bullet> Any acoustic or visual disturbances that take place.
Reporting
Chevron must submit a draft marine mammal monitoring report to NMFS
within 90 days after the completion of pile driving activities, or 60
days prior to the requested issuance of any future IHAs for the
project, or other projects at the same location, whichever comes first.
A final report must be prepared and submitted within 30 calendar days
following receipt of any NMFS comments on the draft report. If no
comments are received from NMFS within 30 calendar days of receipt of
the draft report, the report shall be considered final. The marine
mammal report would include an overall description of work completed, a
narrative regarding marine mammal sightings, and associated PSO data
sheets and/or raw sighting data. Specifically, the report would
include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including: (a) How many and what type of piles were
driven or removed and the method (i.e., impact or vibratory); and (b)
the total duration of time for each pile (vibratory driving) number of
strikes for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring; and
<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.
For each observation of a marine mammal, the following would be
recorded:
<bullet> Name of PSO who sighted the animal(s) and PSO location and
activity at time of sighting;
<bullet> Time of sighting;
<bullet> 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;
<bullet> Distance and location of each observed marine mammal
relative to pile being driven or removed for each sighting;
<bullet> Estimated number of animals (min/max/best estimate);
<bullet> Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, etc.);
<bullet> 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
<bullet> Animal's closest point of approach and estimated time
spent within the harassment zone.
Additionally, Chevron must include the following information in the
report:
<bullet> Number of marine mammals detected within the harassment
zones, by species; and
<bullet> Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensured, and resulting changes in behavior of the
animal(s), if any.
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, Chevron would report the
incident to the Office of Protected Resources (OPR)
(<a href="/cdn-cgi/l/email-protection#48181a66011c1866052726213c273a21262f1a2d38273a3c3b0826272929662f273e"><span class="__cf_email__" data-cfemail="bbebe995f2efeb95f6d4d5d2cfd4c9d2d5dce9decbd4c9cfc8fbd5d4dada95dcd4cd">[email protected]</span></a>), NMFS and to the West Coast
regional stranding network (866-767-6114) as soon as feasible. If the
death or injury was clearly caused by the specified activity, Chevron
would immediately cease the specified activities until NMFS is able to
review the circumstances of the incident and determine what, if any,
additional measures are appropriate to ensure compliance with the terms
of the IHAs. Chevron would not resume their activities until notified
by NMFS.
The report would include the following information:
<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 2, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. There is little information about the nature or severity of
the impacts, or the size, status, or
[[Page 19266]]
structure of any of these species or stocks that would lead to a
different analysis for this activity.
Level A harassment is extremely unlikely given the small size of
the Level A harassment isopleths and the required mitigation measures
designed to minimize the possibility of injury to marine mammals. No
serious injury or mortality is anticipated given the nature of the
activity.
Pile driving activities have the potential to disturb or displace
marine mammals. Specifically, the project activities may result in
take, in the form of Level B harassment from underwater sounds
generated from impact and vibratory pile driving activities. Potential
takes could occur if individuals move into the ensonified zones when
these activities are underway.
The takes by Level B harassment would be due to potential
behavioral disturbance. The potential for harassment is minimized
through construction methods and the implementation of planned
mitigation strategies (see Proposed Mitigation section).
Take would occur within a limited, confined area of each stock's
range. Further, the amount of take authorized is extremely small when
compared to stock abundance.
No marine mammal stocks for which take is proposed are listed as
threatened or endangered under the ESA or determined to be strategic or
depleted under the MMPA. The relatively low marine mammal occurrences
in the area, small shutdown zones, and planned monitoring make injury
takes of marine mammals unlikely. The shutdown zones would be
thoroughly monitored before the pile driving activities begin, and
activities would be postponed if a marine mammal is sighted within the
shutdown zone. There is a high likelihood that marine mammals would be
detected by trained observers under environmental conditions described
for the project. Limiting construction activities to daylight hours
would also increase detectability of marine mammals in the area.
Therefore, the mitigation and monitoring measures are expected to
eliminate the potential for injury and Level A harassment as well as
reduce the amount and intensity of Level B behavioral harassment.
Furthermore, the pile driving activities analyzed here are similar to,
or less impactful than, numerous construction activities conducted in
other similar locations which have occurred with no reported injuries
or mortality to marine mammals, and no known long-term adverse
consequences from behavioral harassment.
Anticipated and authorized takes are expected to be limited to
short-term Level B harassment (behavioral disturbance) as construction
activities would occur intermittently over the course of 30 days.
Effects on individuals taken by Level B harassment, based upon reports
in the literature as well as monitoring from other similar activities,
may include increased swimming speeds, increased surfacing time,
increased haul out time by pinnipeds, or decreased foraging (e.g.,
Thorson and Reyff, 2006; NAVFAC SW, 2018b). Individual animals, even if
taken multiple times, would likely move away from the sound source and
be temporarily displaced from the area due to elevated noise level
during pile removal. Marine mammals could also experience TTS if they
move into the Level B harassment zone. TTS is a temporary loss of
hearing sensitivity when exposed to loud sound, and the hearing
threshold is expected to recover completely within minutes to hours.
Thus, it is not considered an injury. While TTS could occur, it is not
considered a likely outcome of this activity. Repeated exposures of
individuals to levels of sounds that could cause Level B harassment are
unlikely to considerably significantly disrupt foraging behavior or
result in significant decrease in fitness, reproduction, or survival
for the affected individuals. In all, there would be no adverse impacts
to the stock as a whole.
As previously described, a UME has been declared for Eastern
Pacific gray whales. However, we do not expect proposed takes for
authorization in this action to exacerbate the ongoing UME. As
mentioned previously, no injury or mortality is proposed for
authorization, and take by Level B harassment is limited (2 takes over
the duration of the project). Therefore, we do not expect the proposed
take authorization to compound the ongoing UME.
The project is not expected to have significant adverse effects on
marine mammal habitat. There are no known Biologically Important Areas
(BIAs) or ESA-designated critical habitat within the project area, and
the activities would not permanently modify existing marine mammal
habitat. Although harbor seal haul out sites are located in the Bay,
hauled out seals are not likely to be impacted. PSOs during the seismic
retrofit of the Richmond Bridge did not note any decline in use by
harbor seals at Castro Rocks, a haul out site which is approximately 20
to 100 m from the bridge (Greene et al., 2006) and 560 m from the
project area. In addition, any pupping that may occur at Castro Rocks
would take place outside of the work window for the proposed pile
driving activities. The activities may cause fish to leave the area
temporarily. This could impact marine mammals' foraging opportunities
in a limited portion of the foraging range, however, due to the short
duration of activities and the relatively small area of affected
habitat, the impacts to marine mammal habitat are not expected to cause
significant or long-term negative consequences.
In combination, these factors, as well as the available body of
evidence from other similar activities, demonstrate that the potential
effects of the specified activities would have only minor, short-term
effects on individuals. The specified activities are not expected to
impact reproduction or survival of any individual marine mammals, much
less have impacts on annual rates of recruitment or survival.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No serious injury, mortality, or Level A harassment is
anticipated or proposed for authorization;
<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
to marine mammal habitat;
<bullet> The presumed efficacy of the mitigation measures in
reducing the effects of the specified activity; and
<bullet> Monitoring reports from similar work in the Bay have
documented little to no effect on individuals of the same species
impacted by the specified activities.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity would have a negligible impact
on all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for
[[Page 19267]]
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
The amount of take NMFS has authorized is below one-third of the
estimated stock abundances for all seven stocks (refer back to table
8). For most stocks, the proposed take of individuals is less than 2
percent of the abundance of the affected stock (with exception for
harbor seals at 23 percent). This is likely a conservative estimate
because it assumes all takes are of different individual animals, which
is likely not the case for harbor seals, given the nearby haulout. Some
individuals may return multiple times in a day, but PSOs would count
them as separate takes if they cannot be individually identified.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species.
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to Chevron's for conducting pile driving activities in San
Francisco Bay from June 1, 2023 through November 30, 2023, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. A draft of the proposed IHA can be found at: <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 project. We also request comment on the potential renewal
of this proposed IHA as described in the paragraph below. Please
include with your comments any supporting data or literature citations
to help inform decisions on the request for this IHA or a subsequent
renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1 year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activities section of this notice is planned or (2) the activities as
described in the Description of Proposed Activities section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<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 one 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 do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: March 28, 2023.
Catherine Marzin,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2023-06744 Filed 3-30-23; 8:45 am]
BILLING CODE 3510-22-P
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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.