Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental To Replacement of Pier 302 at Naval Base Point Loma, San Diego, California, 68442-68461 [2022-24847]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 87, Number 219 (Tuesday, November 15, 2022)]
[Notices]
[Pages 68442-68461]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-24847]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC335]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental To Replacement of Pier 302 at Naval 
Base Point Loma, San Diego, California

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

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

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SUMMARY: NMFS has received a request from the U.S. Navy for 
authorization to take marine mammals incidental to the replacement of 
Pier 302 at Naval Base Point Loma in San Diego Bay, San Diego, CA. 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-time, one-year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorization and agency responses will be 
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than December 
15, 2022.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email to 
[email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at 
www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Jessica Taylor, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems 
accessing these documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on

[[Page 68443]]

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 July 27, 2022, NMFS received a request from the U.S. Navy for an 
IHA to take marine mammals incidental to construction activities 
associated with replacing Pier 302 at Naval Base Point Loma (NBPL), San 
Diego, CA. Following NMFS' review of the application, the U.S. Navy 
submitted a revised version on September 22, 2022. The application was 
deemed adequate and complete on October 27, 2022. The U.S. Navy's 
request is for take of six species of marine mammals by Level B 
harassment only. Neither the U.S. Navy nor NMFS expect serious injury 
or mortality to result from this activity, therefore, an IHA is 
appropriate.
    NMFS has previously issued IHAs to the U.S. Navy for similar work 
over the past 9 years at NBPL in San Diego Bay (Bay), including IHAs 
issued effective from September 1, 2013, through August 31, 2014 (78 FR 
44539, July 24, 2013; Year 1 Project), October 8, 2014 through October 
7, 2015 (79 FR 65378, November 4, 2014; Year 2 Project), October 8, 
2015 through October 7, 2016 (80 FR 62032, October 15, 2015; Year 3 
Project), October 8, 2016 through October 7, 2017 (81 FR 66628, 
September 28, 2016; Year 4 Project), October 8, 2017 through October 7, 
2018 (82 FR 45811, October 2, 2017; Year 5 Project), September 15, 2020 
through September 14, 2021 (85 FR 33129, June 1, 2020; Floating Dry 
Dock Project), October 1, 2021 through September 30, 2022 (86 FR 7993, 
February 3, 2021; Pier 6 Replacement Project), and January 15, 2022 
through January 14, 2023 (86 FR 48986, September 1, 2021; Fuel Pier 
Inboard Pile Removal Project). The U.S. Navy complied with all the 
requirements (e.g., mitigation, monitoring, and reporting) of the 
previous IHA and information regarding their monitoring results 
specific to NBPL may be found in the Estimated Take section.

Description of Proposed Activity

Overview

    The U.S. Navy plans to replace Pier 302 at the Naval Information 
Warfare Center (NIWC) Pacific Bayside Complex on NBPL. Pier 302 houses 
the U.S. Navy marine mammal pens and support vessels. As part of the 
proposed action, the U.S. Navy would use vibratory extraction to remove 
the existing components of marine mammal pens, and impact and vibratory 
hammers to install new pens. The purpose of the project is to provide 
the U.S. Navy's marine mammal program with adequate facilities to house 
its marine mammals and provide a safe working environment for personnel 
to support the U.S. Navy's overall mission to maintain, train, and 
equip combat ready Naval forces.
    The Navy's proposed activity includes impact and vibratory pile 
driving, which may result in the incidental take of marine mammals, by 
harassment only. No Level A harassment is anticipated to occur, and 
none is proposed for authorization. Due to mitigation measures, only 
takes by Level B harassment are requested. NBPL is located along the 
mouth and northern edge of San Diego Bay, CA. The proposed action 
covers an area of 9,061 feet (ft.)\2\ (842 meters (m)\2\). Construction 
activities would begin on October 1, 2023 and last through September 
30, 2024.

Dates and Duration

    In-water construction activities would occur over 32 days within a 
1 year window from October 1, 2023 to September 30, 2024. The Navy 
states that it will conduct work only in daylight hours. The proposed 
in-water work schedule is shown in Table 1. In-water work would consist 
of 18 days of pile removal, then 14 days of pile installation. Pile 
removal would occur at a rate of one to five piles per day, while pile 
installation would take place at a rate of one to four piles per day, 
depending upon the type of pile. It is assumed that pile removal and 
installation would occur on separate days. In addition to vibratory 
extraction, some piles may be removed by other methods, such as dead 
pull, hydraulic pile clipper, wire saw, underwater chainsaw, or high-
pressure water jet (Table 1). However, these additional methods are not 
expected to result in take and are, therefore, not discussed further. 
In-water pile removal and pile driving is planned from October 1, 2023 
through March 31, 2024 in order to avoid construction activities during 
the breeding and nesting season of the endangered California least 
tern.

                                                Table 1--Proposed In-Water Construction Activity Schedule
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                     Estimated  duration       Total
             Pile type                      Method           Number  of piles      Piles/day      Estimated  blow      per pile  (mm:ss)     estimated
                                                                                                count  per pile \3\          \3\               days
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Pile Removal Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
18'' octagonal concrete...........  Vibratory Extraction   22.................               5  N/A................  15:00..............               5
                                     \1\.
18'' round steel..................  Vibratory Extraction.  3..................               1  N/A................  15:00..............               3

[[Page 68444]]

 
14'' round timber.................  Dead pull............  up to 10...........               1  N/A................  N/A................              10
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
24'' octagonal concrete...........  Impact hammer \2\....  30.................               4  500................  N/A................               8
14'' square concrete..............  Impact Hammer........  2..................               1  250................  N/A................               2
6'' round steel...................  vibratory hammer.....  17.................               5  N/A................  1:00...............               4
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ While other methods of pile removal are possible, vibratory extraction is the most likely method that will be used to extract piles. No quantitative
  exposure analysis was conducted for other potential pile removal methods (hydraulic pile clipper, wire saw, underwater chainsaw, high-pressure water
  jet) as these methods are not expected to result in take.
\2\ With or without high-pressure water jetting occurring simultaneously.
\3\ Estimated durations and blow counts as provided by the construction contractor.

Specific Geographic Region

    NBPL is located along the mouth and northern edge of San Diego Bay, 
California (Figure 1). San Diego Bay is a narrow, crescent-shaped 
natural embayment with an approximate length of 24 kilometers (km) and 
total area of approximately 11,000 acres (44.5 km \2\) (Port of San 
Diego, 2007). Depths of the bay range from 23 meters (m) below mean 
lower low water (MLLW) to less than 1.2 m below MLLW at the southern 
end of the bay (Merkel & Associates, Inc., 2009). The majority of the 
bay is less than 15 m deep (Merkel & Associates, Inc., 2009). The bay 
also includes a main navigation channel, maintained at a depth of 14.3 
m below MLLW. This channel is utilized for transit by private, 
commercial, and military vessels (NOAA, 2010). Water depth in the area 
of Pier 302 ranges from approximately 0-6 m below MLLW.
    San Diego Bay experiences mixed diurnal and semi-diurnal tides with 
a tidal range of approximately 1.7 m. Water temperature in the bay 
typically ranges from 15.1 to 26.1 [deg]C while salinities of the 
proposed project area are similar to those of the open ocean, 32.8 to 
33 parts per thousand (ppt) (Tierra Data Inc., 2012). San Diego Bay is 
heavily used by commercial, recreational, and military vessels. Ship 
noise in the bay has the potential to mask underwater sound produced by 
the proposed project. Based upon recent measurements of underwater 
sound in San Diego Bay, the median ambient underwater sound pressure 
level (SPL) in areas of the bay that may experience project 
construction noise averages approximately 129.6 dB re 1 [mu]Pa.
[GRAPHIC] [TIFF OMITTED] TN15NO22.001


[[Page 68445]]



Figure 1--Proposed Action Area

Detailed Description of Specific Activity

    The purpose of this project is to replace the existing Pier 302 at 
NBPL to provide the Navy's marine mammal program with adequate 
facilities to house its marine mammals and provide a safe working 
environment for personnel supporting the Navy's overall mission to 
maintain, train, and equip combat ready Naval forces. Pier 302 
currently house the U.S. Navy marine mammal pens and small program 
support vessels. The existing Pier 302 was built in 1937 and partially 
modified in 1987. Currently, the steam beams are in poor condition, 
concrete piles are corroded, and timber decking is deteriorated 
(Collins, 2018). The existing pier covers a slightly larger area of 
1,800 ft.\2\ (1,003 m\2\) than the proposed action would cover.
    The Navy proposes to remove the marine mammal pens, gangways, and 
floating walkways from the area and demolish the existing pier. The 
Navy would remove 22 18'' concrete structural piles, 3 18'' steel pipe 
guide piles, and up to 10 14'' timber piles potentially through a 
variety of extraction methods, including vibratory extraction, dead 
pull, hydraulic pile clipper, wire saw, underwater chainsaw, or high-
pressure water jet (Table 1). Existing concrete and steel piles would 
be removed using a vibratory extractor and pile clamp by latching on to 
the pile with the clamp, vibrating the pile to break surface tension, 
and applying upward pressure to extract the whole pile. The dead pull 
method may also be used to remove steel or timber piles by securing the 
piles above the water line and applying upwards pressure to the pile. 
The timber piles are remnant piles from the original 1937 construction, 
but the total number of piles and their placement in the pier footprint 
are unknown. Some of these piles were cut during the 1987 
modifications, but it is unknown how many of them remain nor at what 
depth they were cut. In the case of removal by a hydraulic pile 
clipper, the hydraulic clipper would be placed over each pile and 
lowered to 1 foot (0.3 m) below the mudline, where it would be cut. The 
pile below would remain in place. Diver assistance may or may not be 
required during this specific pile removal activity. Underwater 
chainsaws or wire saws operated by a diver may also be used to remove 
piles at the mudline. Once the piles are removed or cut, a crane would 
remove the pile and set it onto a barge for transport. Ultimately, the 
contractor would decide on the use one of the above described methods 
depending on which proves to be most efficient. Once extracted, the 
piles will be loaded onto a support barge for eventual offloading. For 
purposes of analysis, the Navy assumes that all steel and concrete 
piles would be removed via vibratory extraction. Removal of timber 
piles is assumed to occur via methods that are not anticipated to 
result in take of marine mammals.
    After demolition of the existing pier, the Navy would construct a 
new cement pier and gangways through the installation of 30 24'' (0.6 
m) structural concrete piles, 2 14'' (0.4 m) concrete guide piles, and 
17 6'' (0.2 m) steel pipe guide piles. The piles would be installed 
either through the use of an impact hammer, with our without water 
jetting, or vibratory hammer. Floating walkways, gangways, and marine 
mammal pens would be reinstalled to the north and south of the newly 
constructed pier. The newly constructed Pier 302 would have a similar 
footprint to the original Pier 302.
    Shore side improvements would include the construction of a new 
storm drain outlet and revetment under the base of the new pier. Shore 
side improvement, removal and installation of floating walkways, 
gangways, and marine mammal pens, and extraction methods such as dead 
pull, hydraulic pile clipper, wire saw, underwater chainsaw, or high-
pressure water jet are not expected to result in take of marine mammals 
and are, therefore, not discussed further.
    The Navy's previous work in the portion of San Diego Bay closest to 
the location of this proposed work was the Fuel Pier Replacement 
project, which occurred over 5 years from 2013 to 2018. We reference 
observational data obtained during monitoring required through IHAs 
issued to the Navy in association with this project in the following 
sections. Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, incorporated here by reference, instead of 
reprinting the information. Additional information regarding population 
trends and threats may be found in NMFS' Stock Assessment Reports 
(SARs; www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these 
species (e.g., physical and behavioral descriptions) may be found on 
NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this activity, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS' 
SARs). While no serious injury or mortality is expected to occur, 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.
    There are six marine mammal species that are potentially expected 
to be present during all or a portion of the in-water work associated 
with this project in San Diego Bay, including the California sea lion 
(Zalophus californianus), the northern elephant seal (Mirounga 
angustirostris), the harbor seal (Phoca vitulina), the bottlenose 
dolphin (Tursiops truncatus), the Pacific white-sided dolphin 
(Lagenorhynchus obliquidens), and the common dolphin (Delphinus 
delphis). The Committee on Taxonomy (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/) 
recently determined both the long-beaked and short-beaked common 
dolphin belong in the same species and we adopt this taxonomy. However, 
the SARs still describe the two as separate stocks, and that stock 
information is presented in Table 2. 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 
some species, this geographic area may extend beyond U.S. waters. All 
stocks managed under the MMPA in this region are assessed in NMFS' U.S. 
Pacific 2021 SARs. All values presented in Table 2 are the most recent 
available at the time of publication and are available online at: 
www.fisheries.noaa.gov/national/

[[Page 68446]]

marine-mammal-protection/marine-mammal-stock-assessments).

                                     Table 2--Marine Mammal Species \4\ Likely 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\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                              Order Artiodactyla--Infraorder Cetacea--Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Bottlenose dolphin..............  Tursiops truncatus.....  California Coastal.....  -, -, N             453 (0.06, 346, 2011).        2.7      >=2.0
    Short-beaked common dolphin.....  Delphinus delphis        California/Oregon/       -, -, N             1,056,308 (0.21,             8889     >=30.5
                                       delphis.                 Washington.                                  888,971, 2018).
    Long-beaked common dolphin......  Delphinus delphis        California.............  -, -, N             83,379 (0.216, 69,636,        668     >=29.7
                                       capensis.                                                             2018).
    Pacific white-sided dolphin.....  Lagenorhynchus           California/Oregon/       -, -, N             34,999 (0.222, 29,090,        279          7
                                       obliquidens.             Washington.                                  2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    California sea lion.............  Zalophus californianus.  U.S....................  -, -, N             257,606 (N/A,233,515,       14011       >320
                                                                                                             2014).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulana.........  California.............  -, -, N             30,968 (N/A, 27,348,         1641         43
                                                                                                             2012).
    Northern elephant seal..........  Mirounga angustirostris  California breeding....  -, -, N             187,386 (N/A, 85,369,        5122       13.7
                                                                                                             2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments/ assessments/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)).

    As indicated above, all six species (with seven managed stocks) in 
Table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. While gray whales, 
Risso's dolphins, and Steller sea lions have been sighted around 
California coastal waters in the past, these species' general spatial 
occurrence is such that take is not expected to occur as they typically 
occur more offshore, and they are not discussed further beyond the 
explanation provided here.
    Specifically, gray whales may be observed in San Diego Bay 
sporadically during their January southbound migratory periods (Naval 
Facilities Engineering Command, Southwest and Port of San Diego Bay, 
2013), and have previously been included in take authorizations for 
past projects and IHAs relating to NBPL (refer back to the Year 1-5 
IHAs cited above). However, a recent Monitoring Report from October 8, 
2017 to January 25, 2018 (NAVFAC SW, 2018b) at NBPL, indicated no 
sightings occurred for gray whales. Only two gray whales were spotted 
in the October 8, 2016 to April 30, 2017 (NAVFAC SW, 2017) Monitoring 
Report by the Navy. During another recent pier replacement project at 
Naval Base San Diego, south of the proposed project area, gray whales 
also were not sighted during monitoring (NAVFAC SW, 2022).
    Risso's dolphins have not been seen in San Diego Bay but are known 
to be common in southern California coastal waters (Campbell et al., 
2010). While take of Risso's dolphins have been authorized in three of 
the past IHAs for NBPL (see Year 3 IHA at 80 FR 62032, October 15, 
2015; Year 4 IHA at 81 FR 66628, September 28, 2016; and Year 5 IHA at 
82 FR 45811, October 2, 2017, for examples), no Risso's dolphins were 
sighted during any of those projects.
    Furthermore, other species that occur in the Southern California 
Bight may have the potential for isolated occurrence within San Diego 
Bay or just offshore. In particular, a short-finned pilot whale 
(Globicephala macrorhynchus) was observed off Ballast Point, and a 
Steller sea lion (Eumetopias jubatus monteriensis) was seen in the 
project area during the Year 2 project at NBPL (79 FR 65378, November 
4, 2014). However, these species are not typically observed near the 
project area and, we it is unlikely that they will occur during this 
proposed action. Given the unlikelihood of their exposure to the sounds 
generated from the project, these species are not considered further.

Bottlenose Dolphin

    The California coastal stock of bottlenose dolphin is distinct from 
the offshore population (Perrin et al., 2011; Lowther-Thielking et al., 
2015) and occurs in the immediate (within 1 km of shore) coastal 
waters, primarily between Point Conception, California, and San 
Quintin, Mexico (Hansen, 1990; Carretta et al., 1998; Carretta et al., 
2022). California coastal bottlenose dolphins show little site fidelity 
and likely move within their home range in response to patchy 
concentrations of nearshore prey (Defran and Weller, 1999; Bearzi et 
al., 2009). After finding concentrations of prey, animals may then 
forage within a more limited spatial extent to take advantage of this 
local accumulation until such time that prey abundance is reduced, 
likely then shifting location once again and possibly covering larger 
distances. Oceanographic events may influence the distribution and 
residency patterns of dolphins (Hansen and Defran, 1990; Wells et al., 
1990). Along the California coast, bottlenose dolphin distribution and 
movements may be linked to prey distribution (Defran and

[[Page 68447]]

Weller, 1999; Bearzi et al., 2009). In San Diego Bay, bottlenose 
dolphins may be observed foraging on a variety of fish species, 
including croaker, mackerel, grunts, and mullet (Defran et al., 1986).
    In southern California, coastal bottlenose dolphins are typically 
found within 250 m of the shoreline (Hansen and Defran, 1993). Coastal 
bottlenose dolphins occur sporadically and in highly variable numbers 
and locations in San Diego Bay. Navy surveys indicated that bottlenose 
dolphins were most commonly sighted in April, and more dolphins were 
observed during El Ni[ntilde]o years. Navy surveys frequently result in 
no observations of bottlenose dolphins, and sightings have ranged from 
0-8 groups observed (0-40 individuals). Approximately 67 individual 
bottlenose dolphins were observed during the fourth year of the NBPL 
Fuel Pier Replacement project over 152 days of monitoring. 
Approximately 13 individual bottlenose dolphins were observed over 49 
days of monitoring during Year 5 of the NBPL fuel pier replacement 
project in San Diego Bay (NAVFAC SW, 2017b; 2018b).

Common Dolphin (Short-Beaked and Long-Beaked)

    Short-beaked common dolphins are the most abundant cetacean off 
California and are widely distributed between the coast and 
approximately 300 nautical miles (nmi; 555.6 km) offshore. In contrast, 
long-beaked common dolphins generally occur within 50 nmi (92.6 km) 
offshore. Both stocks may shift their distributions seasonally and 
annually in response to oceanographic conditions and prey availability 
(Carretta et al., 2022). Long-beaked common dolphins tend to prefer 
shallower, warmer waters as compared to the short-beaked common dolphin 
(Perrin, 2009), yet both stocks appear to be more abundant in coastal 
waters during warm-water months (Bearzi, 2005). Within San Diego Bay, 
these two stocks' share overlapping distributions, although they are 
likely long-beaked (as described by the stranding of this species from 
San Diego Bay to the U.S.-Mexico border (Danil and St. Leger, 2011). 
However, it is unlikely that observers would be able to differentiate 
the specific species in the field.
    Common dolphins are often found in large groups of hundreds or even 
thousands. Within San Diego Bay, sightings of common dolphins are 
intermittent and most likely during the late spring and early summer 
when bait fish arrive in the bay. Common dolphins have primarily been 
observed in the north and north central Bay in groups of 6 to less than 
100 animals. The groups typically move rather quickly through the area 
in tight alignment and have been occasionally observed riding the bow 
wave of large ships.
    Several sightings of common dolphins occurred in the bay during the 
previous fuel pier demolition and construction project in 2014 and the 
second period of the previous fuel pier replacement project in 2015. Of 
the course of 100 days of monitoring, 850 common dolphins were observed 
in San Diego Bay in 2015 (NAVFAC SW, 2015). Since it is unlikely for 
the two species to be distinguished in the field, the same estimate of 
individuals is used as a combined estimate for both species.

Pacific White-Sided Dolphin

    Pacific white-sided dolphins are endemic to temperate waters of the 
North Pacific Ocean, and are common both on the high seas and along the 
continental margins (Brownell et al., 1999; Carretta et al., 2022). Off 
the U.S. west coast, Pacific white-sided dolphins occur primarily in 
shelf and slope waters. Sighting patterns from aerial and shipboard 
surveys conducted in California, Oregon and Washington suggest seasonal 
north-south movements, with animals found primarily off California 
during the colder water months and shifting northward into Oregon and 
Washington as water temperatures increase in late spring and summer 
(Green et al., 1992; 1993; Forney and Barlow, 1998; Barlow, 2016; 
Carretta et al., 2022). Pacific white[hyphen]sided dolphins are highly 
social and commonly occur in groups of less than a hundred, although 
groups of several thousands of individuals have been observed. They 
often associate with Risso's dolphins and short[hyphen]beaked common 
dolphins, and occasionally feed in association with California sea 
lions and mixed species aggregations of seabirds.
    Pacific white-sided dolphins are uncommon in San Diego Bay, but 
observations of this species has increased during El Ni[ntilde]o years. 
Given the lack of observations during the fourth year of the NBPL Fuel 
Pier Replacement project, the Navy believes the monitoring data from 
the second year of this project represent the most conservative numbers 
of Pacific white[hyphen]sided dolphins that are likely to occur (NAVFAC 
SW, 2015).

California Sea Lion

    The California sea lion is the most common pinniped species in the 
vicinity of NBPL and northern San Diego Bay. California sea lions 
regularly occur on piers and buoys within and leading into San Diego 
Bay (Merkel & Associates, Inc., 2008). In San Diego Bay, California sea 
lions may also occur on rocks and bait barges.
    Habitat use and distribution varies with sex and reproductive 
stage. Adult males may haul out on land to breed and defend territory 
from mid-May through late July. During August and September, adult 
males migrate to feeding areas as far north as Puget Sound, WA and 
British Columbia (Lowry et al., 1991). Females and immature California 
sea lions remain near the rookeries for most of the year. Most births 
occur from mid-June to mid-July. Different age classes of California 
sea lions are found in the San Diego region throughout the year (Lowry 
et al., 1992). Navy surveys indicate that the local population in San 
Diego Bay comprises mainly adult females and sub-adult males and 
females. Based upon Navy marine mammal surveys conducted throughout the 
north San Diego Bay project area (Merkel & Associates, Inc., 2008; 
Johnson, 2010; Lerma, 2012, 2014), many animals are typically hauled 
out within the vicinity of the proposed action area. Adult males and 
females are known to haul out more often during warm-water months.
    The closest potential haul-out locations to Pier 302 are docks 
associated with Pier 160, approximately 100 m (333 ft) to the north, 
and docks at the end of Pier 99, approximately 550 m (1,804 ft) to the 
south. However, these docks are in constant use for Navy operations and 
training activities. California sea lions may haul-out at those 
locations but are unlikely to remain for very long due to the high 
levels of activity. California sea lions also haul-out at barges 
associated with the Everingham Brothers Bait Barge Company that are 
from 700 to 1,000 m (0.4 to 0.5 nmi) southeast of the proposed action 
area. Beyond these man[hyphen]made structures, there are no known 
natural haul-out locations in the vicinity of the proposed action area.

Harbor Seal

    Pacific harbor seals range from Baja California to the eastern 
Aleutian Islands. 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). Grigg et al. (2009) reported seasonal shifts in harbor 
seal movements based on prey availability.
    Harbor seals may haul out on rocks, buoys, or other structures and 
are relatively uncommon in San Diego Bay, although harbor seals have 
been observed during several past Navy

[[Page 68448]]

projects near Ballast Point (Tierra Data Inc., 2012; Jenkins, 2012), 
Pier 122 (Jenkins, 2012; Bowman, 2014), along the NBPL shoreline 
(Lerma, 2014) and near the Naval Mine and Anti-Submarine Warfare Comman 
(NMAWC) (McConchie, 2014). During the fourth year of the NBPL fuel pier 
replacement project, 88 individual harbor seals were observed over a 
152 day monitoring period (NAVFAC SW, 2017; 2018a).

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. In between the 
spring/summer molting season and winter breeding season, northern 
elephant seals migrate to feeding grounds (Carretta et al., 2022). 
Males and females exhibit spatial segregation in foraging areas with 
males feeding on benthic prey along the continental shelf near the Gulf 
of Alaska and western Aleutian Islands, and females feeding on pelagic 
prey in pelagic areas near the Gulf of Alaska and central North Pacific 
(Le Boeuf et al., 2000).
    Northern elephant seal populations in the U.S. and Mexico have 
recovered after being reduced to near extinction by hunting (Stewart et 
al., 1994) and undergoing a severe population bottleneck and loss of 
genetic diversity that resulted in the population being reduced to only 
an estimated 10-30 individuals (Hoelzel et al., 2002; Carretta et al., 
2022). The northern elephant seal population is estimated to have grown 
at 3.8 percent annually since 1988 (Lowry et al., 2014). There are two 
distinct populations of northern elephant seals, including a breeding 
population in Baja California, Mexico and a breeding population on U.S. 
islands off California. Northern elephant seals in the San Diego region 
could be from either population (Carretta et al., 2021).
    Northern elephant seals occur in the southern California bight, and 
have the potential to occur in San Diego Bay (NAVFAC SW and POSD, 
2013). The most recent documented occurrences of northern elephant 
seals near the proposed project area was in 2015. A single distressed 
juvenile was observed hauled out on the beach to the west of Pier 99 
and approximately 0.6 km south of the proposed project area during the 
second year of work on the Fuel Pier Replacement project at NBPL 
(NAVFAC SW, 2015). In addition, a second juvenile was observed near the 
NBPL Harbor Drive Annex, approximately 3 km north of the proposed 
project area (McConchie, personal communication). Given the continuing, 
long-term increase in the population of northern elephant seals (Lowry 
et al., 2014), there is an increasing possibility of occurrence in the 
project area.

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.

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

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may affect 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

[[Page 68449]]

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 driving and removal. 
The effects of underwater noise from the Navy's proposed activities 
have the potential to result in Level A or Level B harassment of marine 
mammals in the action 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 the Navy'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(s) close enough to be 
harassed due to the presence of equipment or personnel would be within 
the Level B harassment zones from pile driving and would already be 
subject to harassment from the in-water activities. Therefore, any 
impacts to marine mammals are expected to primarily be acoustic in 
nature. Acoustic stressors are generated by heavy equipment operation 
during pile installation and removal (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 the Navy'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. No 
physiological effects other than permanent threshold shift (PTS) are 
anticipated or proposed to be authorized, and therefore are not 
discussed further.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,

[[Page 68450]]

irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Available data 
from humans and other terrestrial mammals indicate that a 40 dB 
threshold shift approximates PTS onset (see Ward et al., 1958, 1959; 
Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; 
Henderson et al., 2008). PTS levels for marine mammals are estimates, 
because there are limited empirical data measuring PTS in marine 
mammals (e.g., Kastak et al., 2008), largely due to the fact that, for 
various ethical reasons, experiments involving anthropogenic noise 
exposure at levels inducing PTS are not typically pursued or authorized 
(NMFS, 2018).
    Temporary Threshold Shift (TTS)--TTS is a temporary, reversible 
increase in the threshold of audibility at a specified frequency or 
portion of an individual's hearing range above a previously established 
reference level (NMFS, 2018). Based on data from cetacean TTS 
measurements (see Southall et al., 2007), a TTS of 6 dB is considered 
the minimum threshold shift clearly larger than any day-to-day or 
session-to-session variation in a subject's normal hearing ability 
(Schlundt et al., 2000; Finneran et al., 2000, 2002). As described in 
Finneran (2016), marine mammal studies have shown the amount of TTS 
increases with cumulative sound exposure level (SELcum) in 
an accelerating fashion: At low exposures with lower SELcum, 
the amount of TTS is typically small and the growth curves have shallow 
slopes. At exposures with higher SELcum, the growth curves 
become steeper and approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
masking, below). For example, a marine mammal may be able to readily 
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal 
is traveling through the open ocean, where ambient noise is lower and 
there are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts. We note that reduced hearing sensitivity as 
a simple function of aging has been observed in marine mammals, as well 
as humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor 
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis), 
and five species of pinnipeds exposed to a limited number of sound 
sources (i.e., mostly tones and octave-band noise) in laboratory 
settings (Finneran, 2015). TTS was not observed in trained spotted 
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive 
noise at levels matching previous predictions of TTS onset (Reichmuth 
et al., 2016). In general, harbor seals and harbor porpoises have a 
lower TTS onset than other measured pinniped or cetacean species 
(Finneran, 2015). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al., 2019a, 2019b, 2020a, 2020b). In addition, TTS 
can accumulate across multiple exposures, but the resulting TTS will be 
less than the TTS from a single, continuous exposure with the same SEL 
(Finneran et al., 2010; Kastelein et al., 2014; 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 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).
    Installing piles for this project requires impact pile driving. 
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.

[[Page 68451]]

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 and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker 2000; Romano 
et al., 2002b) and, more rarely, studied in wild populations (e.g., 
Romano et al., 2002a). For example, Rolland et al. (2012) found that 
noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003), however 
distress is an unlikely result of these projects based on observations 
of marine mammals during previous, similar projects in the area.
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al., 1995). Masking occurs when 
the receipt of a sound is interfered with by another coincident sound 
at similar frequencies and at similar or higher intensity, and may 
occur whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked. The 
masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt 
et al., 2009). San Diego 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

[[Page 68452]]

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
    The Navy'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 
installation is localized to about a 25-ft (7.6-m) radius around the 
pile (Everitt et al., 1980). Turbidity monitoring during high-pressure 
water jetting to remove caissons for the fourth IHA of the Fuel Pier 
Replacement Project revealed relatively minor, if any, changes, with 
only localized decreases in water clarity that dissipated within 3 to 5 
minutes (but up to 10) from the start of jetting (NAVFAC SW, 2018a). 
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 Pier 302 Replacement Project is relatively 
small compared to the total available habitat in San Diego Bay. The 
proposed project area is highly influenced by anthropogenic activities, 
and provides limited foraging habitat for marine mammals. Furthermore, 
pile driving and removal at the proposed project site would not 
obstruct long-term movements or migration of marine mammals.
    Avoidance by potential prey (i.e., fish) of the immediate area due 
to the temporary loss of this foraging habitat is also possible. The 
duration of fish and marine mammal avoidance of this area after pile 
driving stops is unknown, but a rapid return to normal recruitment, 
distribution, and behavior is anticipated. Any behavioral avoidance by 
prey of the disturbed area would still leave significantly large areas 
of potential foraging habitat in the nearby vicinity.
    In-water Construction Effects on Potential Prey--Sound may affect 
marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton, other marine mammals). Marine mammal prey varies by 
species, season, and location. Here, we describe studies regarding the 
effects of noise on known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). Depending on their hearing anatomy and peripheral sensory 
structures, which vary among species, fishes hear sounds using pressure 
and particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
Hastings and Popper (2005) identified several studies that suggest fish 
may relocate to avoid certain areas of sound energy. Additional studies 
have documented effects of pile driving on fish; several are based on 
studies in support of large, multiyear bridge construction projects 
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Many 
studies have demonstrated that impulse sounds might affect the 
distribution and behavior of some fishes, potentially impacting 
foraging opportunities or increasing energetic costs (e.g., Fewtrell 
and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992; 
Santulli et al., 1999; Paxton et al., 2017). In response to pile 
driving, Pacific sardines and northern anchovies may exhibit an 
immediate startle response to individual strikes, but return to 
``normal'' pre[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

[[Page 68453]]

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

    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., vibratory or impact pile driving and removal) 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 
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.
    The Navy's proposed construction activities include the use of 
continuous (vibratory pile-driving) and impulsive (impact pile-driving) 
sources, and therefore the RMS SPL threshold of 160 dB re 1 [mu]Pa is 
applicable for impulsive noise. For continuous noise, the RMS SPL 
threshold of 129.6 dB re 1 [mu]Pa is applicable as a de facto 
harassment threshold, based upon measured noise data for San Diego Bay 
as referenced in the Description of Proposed Activity section.
    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). The Navy's 
proposed activity includes the use of impulsive (impact hammer) and 
non-impulsive (vibratory hammer) sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/

[[Page 68454]]

marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                         PTS onset thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: L0-pk,flat: 219     Cell 2: LE, LF,24h: 199 dB.
                                          dB; LE, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: L0-pk,flat: 230     Cell 4: LE, MF,24h: 198 dB.
                                          dB; LE, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: L0-pk,flat: 202     Cell 6: LE, HF,24h: 173 dB.
                                          dB; LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: L0-pk,flat: 218     Cell 8: LE, PW,24h: 201 dB.
                                          dB; LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: L0-pk,flat: 232     Cell 10: LE,OW,24h: 219 dB.
                                          dB; LE,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 (L0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
  exposure level (LE,) has a reference value of 1[mu]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.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected by sound generated by the 
primary components of the project (i.e., impact and vibratory pile 
driving).
    In order to calculate distances to the Level A harassment and Level 
B harassment thresholds for the methods and piles being used in this 
project, the Navy used acoustic monitoring data from various similar 
locations to develop source levels for the different pile types, sizes, 
and methods proposed for use (Table 5).

                                         Table 5--Source Levels for Proposed Removal and Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Peak sound
                                                                      pressure (dB    Mean maximum     SEL (dB re
                 Method                        Pile size/type          re 1[mu]Pa)   RMS SPL (dB re   1[mu]Pa2 sec)                 Source
                                                                           \1\        1 [mu]Pa) \1\        \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Pile Removal Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Extraction...................  18'' Octagonal Concrete     ..............         \3\ 162  ..............  NAVFAC SW, 2022.
                                          \2\.
                                         18'' Steel Pipe...........  ..............         \4\ 156  ..............  Denes et al., 2016.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Pile Driving....................  24'' Octagonal Concrete...             188             176             166  Caltrans, 2020.
                                         14'' Square Concrete......             183             166             154  Caltrans, 2020.
Vibratory Hammer.......................  6'' Round Steel \5\.......             171             155             155  Illingworth and Rodkin, 2007.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ As measured, or calculated, at 10 m (33 ft).
\2\ In the absence of information on vibratory extraction of 18-inch octagonal concrete piles, source data from 20-inch concrete square piles NAVFAC SW
  (2022) was used as a proxy source level.
\3\ The maximum mean calculated source value for 20-inch square concrete piles (NAVFAC SW, 2022) was 162 dB RMS based on unpublished data from the Pier
  6 Replacement Project.
\4\ Table 20 in Denes et al. (2016) records a value of 152.4 dB RMS at 17 m (56 ft) for vibratory extraction. This data point, and a transmission loss
  of 15LogR, was used to back-calculate a value of 155.9 dB RMS at 10 m (33 ft) (rounded to 156 dB RMS).
\5\ In the absence of information on vibratory installation of 6-inch round steel piles, source data from 12-inch round steel piles (Illingworth &
  Rodkin, 2017) was used as a proxy source level. Abbreviations: [mu]Pa = microPascal; dB = decibel; RMS = root mean square; SPL = sound pressure level;
  m = meters.

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 
and topography. The general formula for underwater TL is:

TL = B * Log10 (R1/R2), where

TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, which is the most appropriate 
assumption for the Navy' proposed activities. The Level B harassment 
zones and areas of zones of

[[Page 68455]]

influence (ZOIs) for the Navy's proposed activities are shown in Table 
6.

                        Table 6--Distance to Level B Harassment Thresholds and ZOI Areas
----------------------------------------------------------------------------------------------------------------
                                                                                   Projected radial distance to
                                                                    Maximum RMS    Level B harassment thresholds
                Method                       Pile size/type        SPL (dB re 1     and ensonified area \1\ \2\
                                                                    [mu]Pa) \1\  -------------------------------
                                                                                    Distance m      Area km\2\
----------------------------------------------------------------------------------------------------------------
                                             Pile Removal Activities
----------------------------------------------------------------------------------------------------------------
                                        18'' Octagonal Concrete.             162           1,445            3.13
Vibratory Extraction..................  18'' Steel Pipe.........             156             575            0.68
----------------------------------------------------------------------------------------------------------------
                                          Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving \3\...............  24'' Octagonal Concrete.             176             117           0.041
Impact Pile Driving...................  14'' Square Concrete....             166              25           <0.01
Vibratory Hammer......................  6'' Round Steel.........             155             494            0.45
----------------------------------------------------------------------------------------------------------------
\1\ The Level B ZOIs for continuous pile removal and installation activities are based on the distance for noise
  to decay to ambient levels (129.6 dB re 1[mu]Pa), while 160 dB was used for impulsive sound.
\2\ Assumes Practical Spreading Loss.
\3\ With or without High-pressure Water Jetting.
Abbreviations: dB re 1 [mu]Pa = decibels referenced to a pressure of 1 microPascal, km\2\ = square kilometers, m
  = meters, ft = feet, RMS = root mean square, ZOI = Zone of Influence.

Level A Harassment Zones

    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the Technical Guidance that can be used 
to relatively simply predict an isopleth distance for use in 
conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources, such as pile installation or removal, the optional 
User Spreadsheet tool predicts the distance at which, if a marine 
mammal remained at that distance for the duration of the activity, it 
would be expected to incur PTS. The isopleths generated by the User 
Spreadsheet used the same TL coefficient as the Level B harassment zone 
calculations (i.e., the practical spreading value of 15). 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 
and resulting isopleths are reported below in Table 7. The maximum 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 activities.

                                                   Table 7--Distances to Level A Harassment Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           Single strike                   Project distances to Level A thresholds  (m)
                                                            Maximum RMS    SEL (dB re 1   Duration  (hrs/-----------------------------------------------
              Method                   Pile size/type      SPL (dB re 1   [mu]Pa\2\ sec)       day)
                                                            [mu]Pa) \1\         \1\                             MF              PW              OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Pile Removal Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Extraction..............  18'' Octagonal                   162             N/A            1.25             0.8             5.6             0.4
                                     Concrete \2\.
                                    18'' Steel Pipe.....         \2\ 156             N/A            0.25             0.1             0.8             0.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Pile Driving...............  24'' Octagonal                   176             166            1.33             4.1        \3\ 62.4             4.5
                                     Concrete.
                                    14'' Square Concrete             166             154            0.25             0.2             2.5             0.2
Vibratory Hammer..................  6'' Round Steel.....             155             155            0.07             0.0             0.3             0.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ As measured at 10 m (33 ft.).
\2\ Table 20 in Denes et al. (2016) records a value of 152.4 dB RMS at 17 m (56 ft.) for vibratory extraction. This data point, and a transmission loss
  of 15LogR, was used to back-calculate a value of 156 dB RMS at 10 m (33 ft.).
\3\ Value is greater than the standard shutdown zone of 20 m (see Proposed Mitigation) and will be monitored as shutdown zone to ensure no Level A takes
  of harbor seals or northern elephant seals occur during impact pile driving of 24-inch octagonal concrete piles.
Abbreviations: RMS = root mean square, dB re 1 [mu]Pa = decibels referenced to a pressure of 1 microPascal, m = meters, ft = feet, MF = mid-frequency
  cetaceans, PW = phocid pinnipeds, OW = otariid pinnipeds.

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. Unless otherwise specified, the term 
``pile driving'' in this section, and all following sections, may refer 
to either pile installation or removal. NMFS has carefully reviewed the 
Navy's analysis and concludes that it represents an appropriate and 
accurate method for

[[Page 68456]]

estimating incidental take that may be caused by the Navy's activities.
    Daily occurrence estimates of marine mammals in the proposed 
project area are based upon the Year 4 IHA monitoring report from the 
Fuel Pier Replacement Project (NAVFAC SW, 2017b). Year 4 is expected to 
be most representative of typical species occurrences as this 
monitoring period had the highest number of activity days and the 
highest average number of animals observed per day for the three most 
common species in the area (California sea lion, harbor seal, 
bottlenose dolphin), with the exception of Year 2. However, Year 2 was 
an El Ni[ntilde]o year and not considered representative of typical 
species occurrences. The Year 2 monitoring report data was used for any 
species not observed in Year 4 (common dolphin, Pacific white-sided 
dolphin, northern elephant seal) (NAVFAC SW, 2015) (Table 8). Years 1, 
3, and 5 included significantly less monitoring effort than Years 2 and 
4, and may also not be representative of typical species richness and 
occurrences.

                Table 8--Total and Daily Species Occurrences During Years 2 and 4 IHA Monitoring
----------------------------------------------------------------------------------------------------------------
                                                    Year 2 IHA  (100 monitoring     Year 4 IHA  (152 monitoring
                                                       days;  El Nino year)                   days)
                     Species                     ---------------------------------------------------------------
                                                                   Average  per                    Average  per
                                                  Total observed        day       Total observed        day
----------------------------------------------------------------------------------------------------------------
California sea lion.............................           7,507            75.1           2,263          * 14.9
Harbor seal.....................................             248             2.5              88           * 0.6
Bottlenose dolphin..............................             695               7              67           * 0.4
Common dolphin..................................             850           * 8.5             N/a             N/a
Pacific white-sided dolphin.....................              27           * 0.3             N/a             N/a
Northern elephant seal..........................           \1\ 1           \1\ 1             N/a             N/a
----------------------------------------------------------------------------------------------------------------
* Mean estimate used for daily occurrences for current analysis.
\1\ Same individual hauled out each day.

    Year 4 monitoring consisted of the longest effort of all 5 IHA 
years for the Navy Fuel Pier Replacement Project, and daily occurrence 
estimates for California sea lions, harbor seals, and bottlenose 
dolphins were selected from this year. Common dolphins, Pacific white-
sided dolphins, and northern elephant seals were not sighted in Year 4; 
however, these species were sighted in Year 2 monitoring. Pacific 
white-sided dolphins were only sighted during this year. Daily 
occurrence estimates for common dolphins and Pacific white-sided 
dolphins were selected from Year 2. Only one northern elephant seal was 
sighted during the Year 2 monitoring, and the same individual was 
hauled out each day. Using a daily occurrence estimate from past 
monitoring was, therefore, not an accurate approach for estimating 
occurrence of northern elephant seals. Past monitoring efforts, 
including the one northern elephant seal sighted during Year 2 
monitoring and a sighting north of the project area, (McConchie, 2015; 
NAVFAC SW, 2015) documented a total of two juvenile northern elephant 
seals in the proposed project area, as described earlier in the 
Description of Marine Mammals in Areas of Specified Activities section. 
Due to increasing stock numbers, there is a reasonable probability that 
this species could be sighted in the proposed project area during 
construction activities. Instead of using past monitoring data to 
estimate daily occurrence, it is expected that two northern elephant 
seals may be observed in the proposed project area during construction 
activities, based upon previous sighting data. The Navy added a buffer 
of five seals to this estimate for a total of seven expected elephant 
seals in the area during construction activities, and NMFS agrees with 
this approach.
    Monitoring during Year 4 yielded an observation of 2,263 California 
sea lions over the course of the 152-day monitoring period. These 
observations equate to an average of 14.9 California sea lions observed 
per day, and approximately 15 California sea lions expected to be in 
the vicinity of Pier 302, when this estimate is rounded.
    Based upon monitoring during Year 4, 88 harbor seals were observed 
over the course of the 152-day monitoring period. These observations 
equate to an average of 0.6 harbor seals observed per day, and 
approximately 1 seal per day expected to be in the vicinity of Pier 302 
when this estimate is rounded.
    Monitoring during Year 4 yielded an observation of 67 bottlenose 
dolphins in the proposed project area over the course of the 152-day 
monitoring period. This observation equates to an average of 0.4, or 1 
if rounded, bottlenose dolphins expected to be in the vicinity of Pier 
302 each day of the proposed construction activities.
    During Year 2 monitoring, 850 common dolphins were sighted in the 
proposed project area over the course of the 152-day monitoring period. 
This equates to an average of 8.5 common dolphins observed per day. 
When rounded to the nearest whole number, 9.0 individuals are expected 
to be sighted per day in the vicinity of Pier 302.
    Monitoring during Year 2 documented seven sightings of Pacific 
white-sided dolphins, comprising 27 individuals, with an average of 
0.28 individuals sighted per day of monitoring. Rounding this estimate 
to the nearest whole number leads to 1.0 individual per day to be 
expected to be in the vicinity of Pier 302 during the proposed 
construction activities.

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.
    Daily occurrence estimates were multiplied by the number of days of 
pile removal and installation (32 days) to calculate estimated take by 
Level B harassment of California sea lions, harbor seals, bottlenose 
dolphins, common dolphins, Pacific white-sided dolphins, and northern 
elephant seals (Table 9).

[[Page 68457]]



      Table 9--Proposed Takes by Level B Harassment and Percent of Stock Proposed To Be Authorized for Take
----------------------------------------------------------------------------------------------------------------
                                                                                                 Percentage of
                                                           Expected daily    Proposed take by      population
                        Species                               average            Level B         proposed to be
                                                            individuals         harassment       authorized for
                                                                                                      take
----------------------------------------------------------------------------------------------------------------
California sea lion \1\................................                 15                480               0.19
Harbor seal \1\........................................                  1                 32               0.10
Bottlenose dolphin \1\.................................                  1                 32                7.1
Common dolphin (long and short beaked) \2\.............                  9                288             * 0.35
Pacific white-sided dolphin \2\........................                  1                 32               0.09
Northern elephant seal.................................              (\3\)                  7              0.004
----------------------------------------------------------------------------------------------------------------
\1\ Average daily counts based on observations during Year 4 Fuel Pier Replacement Project Monitoring (NAVFAC
  SW, 2017b).
\2\ Average daily counts based on observations during Year 2 Fuel Pier Replacement Project Monitoring (NAVFAC
  SW, 2015).
\3\ Expected potential of two northern elephant seals over the duration of project activity with a +5 buffer for
  Level B Take.
* Percent population calculated for each stock of common dolphins. Percentage in the table represents the
  percent of take of long-beaked common dolphins as this would be a greater percentage than if all take were
  attributed to short-beaked common dolphins (0.03 percent).

    By using the sighting-based approach, take values are not affected 
by the estimated harassment distances from Tables 6 and 7. Given the 
very small Level A harassment isopleths for all species and proposed 
mitigation measures, no take by Level A harassment is anticipated or 
proposed for this authorization.

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, and impact on 
operations.
Shutdown Zones
    Before the commencement of in-water construction activities, the 
Navy would establish shutdown zones for all activities. The purpose of 
a shutdown zone is 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. During all in-
water construction activities, the Navy has proposed to implement a 
standard 20 m (66 ft) shutdown zone, with the exception of a 70 m (230 
ft) zone for phocids during the use of impact pile driving for the 24'' 
octagonal concrete piles. These distances exceed the estimated Level A 
harassment distances (Table 10). During the impact installation of the 
24-inch octagonal concrete piles, the shutdown zone for phocids will be 
buffered to 70 m (230 ft) to encompass the Level A harassment zone. 
Adherence to this expanded shutdown zone will avoid the potential for 
the take of phocids by Level A harassment during impact pile driving. 
If a marine mammal enters a buffered shutdown zone, in-water activities 
would be stopped until visual confirmation that the animal has left the 
zone or the animal is not sighted for 15 minutes.
    All marine mammals will be monitored in the Level B harassment 
zones and throughout the area as far as visual monitoring can take 
place. If a marine mammal enters the Level B harassment zone, in-water 
activities will continue and the animal's presence within the estimated 
harassment zone will be documented.
    The Navy 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 are equivalent to the Level B harassment zones for each activity. 
If a marine mammal species not covered under this IHA enters the 
shutdown zone, all in-water activities will cease until the animal 
leaves the zone or has not been observed for at least 1 hour, and NMFS 
will be notified about species and precautions taken. Pile removal will 
proceed if the non-IHA species 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 the Navy, the in-water activity will 
be allowed to continue until the safety concern has been addressed, and 
the animal will be continuously monitored. The Navy Point of Contact 
(POC) will be consulted before re-commencing activities.

[[Page 68458]]



                              Table 10--Shutdown Zones and Level B Harassment Zones
----------------------------------------------------------------------------------------------------------------
                                                               Shutdown zones m (ft)                  Level B
            Method               Pile size/type  ------------------------------------------------   harassment
                                                        MF              PW              OW         zones  m (ft)
----------------------------------------------------------------------------------------------------------------
                                             Pile Removal Activities
----------------------------------------------------------------------------------------------------------------
Vibratory Extraction..........  18'' Octagonal           20 (66)         20 (66)         20 (66)   1,445 (4,742)
                                 Concrete.
                                18''Steel Pipe..         20 (66)         20 (66)         20 (66)     575 (1,888)
----------------------------------------------------------------------------------------------------------------
                                          Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving...........  24'' Octagonal           20 (66)    \1\ 70 (230)         20 (66)       117 (383)
                                 Concrete.
                                14'' Square              20 (66)         20 (66)         20 (66)         25 (82)
                                 Concrete.
Vibratory Hammer..............  6'' Round Steel.         20 (66)         20 (66)         20 (66)     494 (1,619)
----------------------------------------------------------------------------------------------------------------
\1\ Level A ZOI buffered from 62.5 m up to 70 m.

Protected Species Observers

    The placement of protected species observers (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.

Pre-Activity Monitoring

    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 that 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 impact pile driving and at any time following cessation of 
impact pile driving for a period of 30 minutes or longer.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring during pile driving activities would be 
conducted by PSOs meeting NMFS' the following requirements:
     Independent PSOs (i.e., not construction personnel) who 
have no other assigned tasks during monitoring periods would be used;
     At least one PSO would have prior experience performing 
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization;
     Other PSOs may substitute education (degree in biological 
science or related field) or training for experience; and
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator would be designated. The lead 
observer would be required to have prior experience

[[Page 68459]]

working as a marine mammal observer during construction.
    PSOs would have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    The Navy would have at least two PSOs stationed at the best 
possible vantage points in the project area to monitor during all pile 
driving activities. If a PSO sights a marine mammal in the shutdown 
zone, the PSO should alert the ``command'' PSO to notify the equipment 
operator to shut down. If the ``command PSO'' does not respond, any PSO 
has the authority to notify the need for a shutdown. If the ``command'' 
PSO calls for a shutdown, the ``command'' PSO will let the contractor 
know when activities can re-commence. Additional PSOs may be employed 
during periods of low or obstructed visibility to ensure the entirety 
of the shutdown zones are monitored. A marine mammal monitoring plan 
will be developed and submitted to NMFS for approval prior to 
commencing in-water construction activities.

Reporting

    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving activities, or 60 
days prior to a requested date of issuance of any future IHAs for the 
project, or other projects at the same location, whichever comes first. 
The marine mammal report would include an overall description of work 
completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report would include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including: (a) How many and what type of piles were 
driven or removed and the method (i.e., impact or vibratory); and (b) 
the total duration of time for each pile (vibratory driving) number of 
strikes for each pile (impact driving);
     PSO locations during marine mammal monitoring; and
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance.
    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. 
Specifically, PSOs will record the following:
     Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting;
     Time of sighting;
     Identification of the animal(s) (e.g., genus/species, 
lowest possible taxonomic level, or unidentified), PSO confidence in 
identification, and the composition of the group if there is a mix of 
species;
     Distance and location of each observed marine mammal 
relative to the pile being driven or hole being drilled for each 
sighting;
     Estimated number of animals (min/max/best estimate);
     Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
     Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses thought to have resulted from the 
activity (e.g., no response or changes in behavioral state such as 
ceasing feeding, changing direction, flushing, or breaching);

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 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 
mortality is anticipated given the nature of the activity.
    Pile installation and removal activities have the potential to 
disturb or displace marine mammals. Specifically, the project 
activities may result in take, in the form of Level A and Level B 
harassment from underwater sounds generated from impact and vibratory 
pile installation, and vibratory pile removal activities. Potential 
takes could occur if individuals move into the ensonified zones when 
these activities are underway.
    The takes from Level B harassment would be due to potential 
behavioral disturbance. No serious injury or mortality is anticipated 
for any stocks presented in this analysis given the nature of the 
activity and mitigation measures designed to minimize the

[[Page 68460]]

possibility of injury. 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. Level B harassment would be reduced to the level of least 
practicable adverse impact through use of mitigation measures described 
herein. Further, the amount of take authorized is extremely small when 
compared to stock abundance.
    No marine mammal stocks for which incidental take authorization is 
proposed are listed as threatened or endangered under the ESA or 
determined to be strategic or depleted under the MMPA. The relatively 
low marine mammal occurrences in the area, small shutdown zones, and 
proposed monitoring make injury takes of marine mammals unlikely. The 
shutdown zones would be thoroughly monitored before the proposed 
vibratory pile installation and removal begins, and construction 
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 proposed project. Limiting construction activities to daylight 
hours will also increase detectability of marine mammals in the area. 
Therefore, the proposed mitigation and monitoring measures are expected 
to eliminate the potential for injury and Level A harassment as well as 
reduce the amount and intensity for Level B behavioral harassment. 
Furthermore, the pile installation and removal activities analyzed here 
are similar to, or less impactful than, numerous construction 
activities conducted in other similar locations which have occurred 
with no reported injuries or mortality to marine mammals, and no known 
long-term adverse consequences from behavioral harassment.
    Anticipated and authorized takes are expected to be limited to 
short-term Level B harassment (behavioral disturbance) as construction 
activities will occur over the course of 32 weeks. 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, or 
decreased foraging (e.g., Thorson and Reyff, 2006; NAVFAC SW, 2018b). 
Individual animals, even if taken multiple times, will likely move away 
from the sound source and be temporarily displaced from the area due to 
elevated noise level during pile removal. Marine mammals could also 
experience TTS if they move into the Level B monitoring 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.
    The proposed project is not expected to have significant adverse 
effects on marine mammal habitat. There are no Biologically Important 
Areas or ESA-designated critical habitat within the project area, and 
the proposed activities would not permanently modify existing marine 
mammal habitat. 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, we believe that 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 affect rates of recruitment or survival and 
would therefore not result in population-level impacts.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect any of the species 
or stocks through effects on annual rates of recruitment or survival:
     No serious injury or mortality or Level A harassment is 
anticipated or authorized;
     The specified activity and associated ensonified areas are 
very small relative to the overall habitat ranges of all species;
     Biologically important areas or critical habitat have not 
been identified within the project area;
     The lack of anticipated significant or long-term effects 
to marine mammal habitat;
     The Navy is required to implement mitigation measures to 
minimize impacts, such as PSO observation and shutdown zones of 20 m 
(66 ft); and,
     Monitoring reports from similar work in San Diego 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 will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The amount of take NMFS proposes to authorize is below one-third of 
the estimated stock abundances for all seven species (refer back to 
Table 9). For most requested species, the proposed take of individuals 
is less than 1 percent of the abundance of the affected stock (with 
exception for bottlenose dolphins at 7.1 percent). This is likely a 
conservative estimate because it assumes all takes are of different 
individual animals, which is likely not the case. Some individuals may 
return multiple times in a day, but PSOs would count them as separate 
takes if they cannot be individually identified.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals,

[[Page 68461]]

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 the U.S. Navy for conducting the NBPL Pier 302 
Replacement Project in San Diego Bay from October 1, 2023 through 
September 30, 2024, provided the previously mentioned mitigation, 
monitoring, and reporting requirements are incorporated. A draft of the 
proposed IHA can be found at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

Request for Public Comments

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

    Dated: November 9, 2022.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2022-24847 Filed 11-14-22; 8:45 am]
BILLING CODE 3510-22-P