[Federal Register Volume 86, Number 136 (Tuesday, July 20, 2021)]
[Notices]
[Pages 38274-38295]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-15378]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB128]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Naval Base Point Loma Fuel Pier 
Inboard Pile Removal Project

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

DATES: Comments and information must be received no later than August 
19, 2021.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Written comments 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

[[Page 38275]]

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: Kelsey Potlock, 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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 issued or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization may be provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and would 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 February 3, 2021, NMFS received a request from the United States 
Navy (Navy) for an IHA to take marine mammals' incidental to pile 
removal activities at Naval Base Point Loma in San Diego Bay, 
California. We submitted questions to the Navy on the application on 
March 12, 2021. We received responses on March 23, 2021; April 5, 2021; 
May 5, 2021; and May 12, 2021. Meetings between NMFS, the Navy, and 
their contractors were held on May 12, 2021 and May 24, 2021. A final 
revised version was received by NMFS on May 24, 2021. The application 
was deemed adequate and complete on May 17, 2021. The Navy's request is 
for the take of a small number of six species of marine mammals by 
Level B harassment only. Neither the Navy nor NMFS expects serious 
injury or mortality to result from these activities. Therefore, an IHA 
is appropriate.
    Naval Base Point Loma provides berthing and support services for 
Navy submarines and other fleet assets. The existing fuel pier 
previously served as a fuel depot for loading and unloading fuel. Naval 
Base Point Loma is the only active Navy fueling facility in southern 
California. The current project is to remove piles that were part of 
the old pier that was replaced over the past few years. This proposed 
IHA includes up to 84 days of in-water pile removal activities.
    NMFS has previously issued incidental take authorizations to the 
Navy for similar activities over the past 8 years at Naval Base Point 
Loma in San Diego 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), and October 1, 
2021 through September 30, 2022 (86 FR 7993, February 3, 2021; Pier 6 
Replacement Project). The Navy has complied with all the requirements 
(e.g., mitigation, monitoring, and reporting) of past IHAs. Monitoring 
reports from these activities are available on NMFS website (https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities).

Description of Proposed Activities

Overview

    The purpose of the proposed project is to remove old piles from the 
Fuel Pier at Naval Base Point Loma to allow for continued Naval Fleet 
readiness activities. Specifically, in-water construction work includes 
the removal of 409 piles by a variety of techniques (i.e., one to two 
pile clippers, an underwater chainsaw, a diamond wire saw, or a 
vibratory hammer, possibly with assistance from a diver). Concurrent 
pile removal may occur for some piles through the use of two pile 
clippers only. The piles include an estimated 12 13-inch diameter 
polycarbonate fender piles, 56 14-inch diameter concrete fender piles, 
and 341 16-inch diameter concrete structural piles.
    Dredging activities would occur both during and after pile removal 
and within the one-year period of the IHA. However, take of marine 
mammals is not expected to result from the NBPL dredging activities, 
the Navy did not request take incidental to dredging activities, and 
they are not discussed further.
    The pile removal activities can result in the take of marine 
mammals from the sounds produced in the water, which could result in 
behavioral harassment or auditory injury to marine mammals within the 
estimated isopleths.

Dates and Duration

    The work described in this proposed IHA is scheduled to begin 
January 15,

[[Page 38276]]

2022 and be valid for one year after the start date (end January 14, 
2023). Under the terms of a previously developed Memorandum of 
Understanding (MOU) between the Navy and the U.S. Fish and Wildlife 
Service (USFWS), the Navy would only be performing in-water activities 
during a 196-day period from September 16 to March 31 to not interfere 
with the California least tern (Sterna antillarum browni) nesting 
season.
    Pile removal is planned to occur during daylight hours only over 84 
days within the previously described 196 day period. Per the Navy's 
application, daylight hours constitute no earlier than 45 minutes after 
sunrise or later than 45 minutes before sunset.

Specific Geographic Region

    The activities would occur near the mouth of the San Diego Bay 
(Figure 1). San Diego Bay is a narrow, crescent-shaped natural 
embayment oriented northwest-southeast with an approximate length of 24 
kilometers (km) (15 miles (mi)) and a total area of roughly 4 km\2\ 
(11,000 acres; Port of San Diego, 2007). The width of the Bay ranges 
from 0.3 to 5.8 km (0.2 to 3.6 mi), and depths range from 23 m (74 ft) 
MLLW near the tip of Ballast Point to less than 1.2 m (4 ft) at the 
southern end (Merkel and Associates, Inc., 2009). Approximately half of 
the Bay is less than 4.5 meters (m) (15 feet (ft)) deep and much of it 
is less than 15 m (50 ft) deep (Merkel and Associates, Inc., 2009). The 
northern and central portions of the Bay have been shaped by historical 
dredging and filling to support large ship navigation and shoreline 
development. The United States Army Corps of Engineers dredges the main 
navigation channel in the Bay to maintain a depth of 14 m (47 ft) MLLW 
and is responsible for providing safe transit for private, commercial, 
and military vessels within the bay (NOAA, 2010). Outside of the 
navigation channel, the bay floor consists of platforms at depths that 
vary slightly (Merkel and Associates, Inc., 2009). Within the Central 
Bay, typical depths range from 10.7-11.6 m (35-38 ft) MLLW to support 
large ship turning and anchorage, and small vessel marinas are 
typically dredged to depths of 4.6 m (15 ft) MLLW (Merkel and 
Associates, Inc., 2009).
[GRAPHIC] [TIFF OMITTED] TN20JY21.001

    Benthic substrate in San Diego Bay is largely sand (Naval 
Facilities Engineering Command, Southwest and Port of San Diego Bay, 
2013) as tidal currents tend to keep the finer silt and clay fractions 
in suspension, except in harbors and elsewhere in the lee of structures 
where water movement is diminished. Much of the shoreline consists of 
riprap and manmade structures. The project site is shallow subtidal and 
has an eelgrass bed located less than 1-acre in size (Merkel and 
Associates, Inc., 2018). Over-water structures, such as the existing 
Marine

[[Page 38277]]

Group Boat Works, LLC (MGBW; see 85 FR 33129, June 1, 2020) piles and 
dock structures, provide substrates for the growth of algae and 
invertebrates off the bottom and support abundant fish populations. 
Eelgrass present within the project site is important habitat for 
invertebrates, fishes, and birds (Naval Facilities Engineering Command, 
Southwest and Port of San Diego Bay, 2013).
    San Diego Bay is heavily used by commercial, recreational, and 
military vessels, with an average of 82,413 vessel movements (in or out 
of the Bay) per year (approximately 225 vessel transits per day), a 
majority of which are presumed to occur during daylight hours. This 
number of transits does not include recreational boaters that use San 
Diego Bay, estimated to number 200,000 annually (San Diego Harbor 
Safety Committee, 2009).
    Underwater data collect by the Navy have determined an averaged 
median ambient noise level to be approximately 129.6 decibel pressure 
of 1 microPascal (dB re 1 [mu]Pa) for north San Diego Bay (NAVFAC SW, 
2020). Their findings demonstrated ambient sound levels to be higher 
than the 120 dB re 1 [mu]Pa sound threshold for Level B harassment from 
non-impulsive sources. This is based on sound levels collected during 
the five past IHA applications submitted to NMFS (Navy 2013b, 2014, 
2015, 2016, and 2017a) that determined sound levels ranged between 126 
and 137 dB re 1 [mu]Pa (L50; Naval Facilities Engineering 
Command, Southwest, 2018).
    Section 2.2 of the application provides extensive additional 
details about the project area.

Detailed Description of Specific Activity

    The purpose of this project is to deconstruct the old Fuel Pier to 
allow for the full use of the newly developed Fuel Pier. The Navy would 
remove 409 old piles using single or concurrent pile clippers, a 
diamond wire saw, an underwater chainsaw, and/or a vibratory hammer. 
While each removal method is assessed independently, multiple tools may 
be needed to remove each pile. However, with the exception for the 
possible concurrent use of two pile clippers, removals would be 
conducted independently as to minimize disturbance zones.
    The hydraulic pile clippers (24-inch) would be placed over each 
pile and lowered to the mudline where they use a horizontal motion to 
cut the pile. While pile clippers may be used on any of the pile types 
(13-inch polycarbonate, 14-inch concrete, 16-inch concrete), any 
concurrent use of pile clippers (2 pile clippers) would only occur for 
the 14-inch and 16-inch concrete piles. Underwater divers may be needed 
for pile clipper use.
    The use of a single diamond wire saw, underwater chainsaw, or 
vibratory hammer may be used for the 14-inch and 16-inch concrete 
piles. The diamond wire saw rig and vibratory hammer would be placed 
around the pile. The saw would cut through the pile using a worker-
operated level bar. The vibratory hammer would loosen the pile from the 
surrounding sediment, allowing it to be pulled out vertically from the 
ground. Lastly, a diver-operated underwater chainsaw would be used to 
cut through the piles. Once the piles are clipped or cut, an on-site 
crane would be used to vertically remove piles. Removed piles would be 
placed on a barge for transport to a processing yard.
    The Navy's contractor will choose the most appropriate method for 
each pile, as discussed in the submitted project application. Pile 
clippers (24-inch) would be used first, either by single use for one 
pile or concurrent use on two piles. If the pile clippers cannot be 
used successfully, the underwater chainsaw would be employed to cut 
concrete piles. If both of these methods are both unsuccessful, the 
diamond wire saw would be utilized. Lastly, the vibratory hammer would 
be implemented to loosen any relatively intact piles to allow for 
vertical removal by crane. However, the Navy has noted in their 
application that the contractor performing the work will choose the 
appropriate method of pile removal.
    All proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (see Proposed Mitigation, 
Monitoring, and Reporting Measures).

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. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    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 recently determined both the long-
beaked and short-beaked common dolphin belong in the same species and 
we adopt this taxonomy, but the SARs still describe the two as separate 
stocks and that stock information is presented in Table 1. California 
sea lions are typically present year-round and are very common in the 
project area, but may have variable sightings based off Navy marine 
mammal surveys of northern San Diego Bay. Bottlenose dolphins and 
harbor seals are also common and likely to be present year-round, but 
with more variable occurrence in San Diego Bay in comparison to 
California sea lions. Common dolphins are known to occur in nearshore 
waters outside San Diego Bay, but are only rarely observed near or in 
the Bay. The remaining species are known to occur in nearshore waters 
outside San Diego Bay, but are generally only rarely observed near or 
in the bay. However, recent observations indicate that these species 
may occur in the project area and therefore could potentially be 
subject to incidental harassment from the aforementioned activities.
    Table 1 lists all marine mammal species with expected potential for 
occurrence in the vicinity of Naval Base Point Loma during the project 
timeframe and summarizes key information, 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's SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments). While no mortality is 
anticipated or authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species and other threats. For 
taxonomy, we followed the Society for Marine

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Mammalogy's Committee on Taxonomy (2020).
    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's stock abundance estimates, for most species, represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's 2019 Pacific SARs (Carretta et al., 2020a) and draft 2020 U.S. 
Pacific SARs (Carretta et al., 2020b). All values presented in Table 1 
are the most recent available at the time of publication and are 
available in the 2019 Pacific SARs and draft 2020 Pacific SARs 
(available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

         Table 1--Species and Stocks That Temporally and Spatially Co-Occur With the Project to a Degree That Take Is Reasonably Likely To Occur
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                                                                                         ESA/MMPA status;    Stock abundance (CV,
             Common name                  Scientific name               Stock            strategic  (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
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                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
    Bottlenose dolphin..............  Tursiops truncatus.....  California coastal.....  -, -, N             453 (0.06, 3436, 2011)        2.7      >=2.0
    Short-beaked common dolphin.....  Delphinus delphis......  California/Oregon/       -, -, N             969,861 (0.17,               8393       >=40
                                                                Washington.                                  839,325, 2014).
    Long-beaked common dolphin......  Delphinus capensis.....  California.............  -, -, N             101,305 (0.49, 68,432,        657     >=35.4
                                                                                                             2014).
    Pacific white-sided dolphin.....  Lagenorhynchus           California/Oregon/       -, -, N             26,814 (0.28, 21,195,         191        7.5
                                       obliquidens.             Washington.                                  2014).
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                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    California sea lion.............  Zalophus californianus.  United States..........  -, -, N             257,606 (N/A, 233,515,      14011       >320
                                                                                                             2014).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  California.............  -, -, N             30,968 (N/A, 27,348,         1641         43
                                                                                                             2012).
    Northern elephant seal..........  Mirounga angustirostris  California breeding....  -, -, N             179,000 (N/A, 81,368,        4882        8.8
                                                                                                             2010).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 (M/SI) from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.

    As indicated above, all six species (with seven managed stocks) in 
Table 1 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur, and we have proposed 
authorizing it. While Risso's dolphins and gray whales 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 Naval Base Point Loma (refer back to 
the Year 1-5 IHAs cited above). However, in the most recent Monitoring 
Report from October 8, 2017 to January 25, 2018 (Year 5 IHA; NAVFAC SW, 
2018) at Naval Base Point Loma, no sightings occurred for gray whales. 
Only two gray whales were spotted in the October 8, 2016 to April 30, 
2017 (Year 4 IHA; NAVFAC SW, 2017) Monitoring Report by the Navy.
    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 Naval Base Point Loma (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, due to the relatively shallow depth near the project 
site the more sheltered and inland location of this project site within 
San Diego Bay, and the inclusion of the buffered shutdown zone within 
the Navy's monitoring and mitigation plan, NMFS expects that a very low 
probability of take exists for these two species. Because of these 
reasons, no take has been requested nor proposed to be authorized for 
gray whales or Risso's dolphins during this proposed IHA.
    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 Naval Base Point Loma (79 FR 
65378, November 4, 2014). However, these species are not typically 
observed near the project area and, we do not believe it likely 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

    As seen in the Navy's marine mammal surveys of San Diego Bay, cited 
above,

[[Page 38279]]

coastal bottlenose dolphins have occurred within San Diego Bay 
sporadically and in variable numbers and locations. The California 
coastal stock of bottlenose dolphin is distinct from the offshore 
population and is resident in the immediate (within 1 km of shore) 
coastal waters, occurring primarily between Point Conception, 
California, and San Quintin, Mexico. Occasionally, during warm-water 
incursions such as during the 1982-1983 El Ni[ntilde]o events, their 
range extends as far north as San Francisco Bay (Carretta et al., 
2017). They are commonly found in groups of 2 to 15 individuals and in 
larger groups offshore.
    Coastal bottlenose dolphins have occurred sporadically and in 
highly variable numbers and locations in San Diego Bay. Navy surveys 
showed that bottlenose dolphins were most commonly sighted in April, 
and there were more dolphins observed during El Ni[ntilde]o years.
    California coastal bottlenose dolphins show little site fidelity 
and likely move within their home range in response to patchy 
concentrations of nearshore prey (Defran et al., 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. Navy surveys frequently result in no observations of 
bottlenose dolphins, and sightings have ranged from 0-8 groups observed 
(0-40 individuals).

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 (Carretta et al., 2014). 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 (Carretta et 
al., 2014).
    Pacific white-sided dolphins are uncommon in San Diego Bay, but 
observations of this species increased during El Ni[ntilde]o years. 
Monitoring during the Year 2 IHA documented seven sightings of Pacific 
white-sided dolphins, comprising 27 individuals, with a mean group size 
of 3.85 individuals per sighting and an average of 0.28 individuals 
sighted per day of monitoring.

Common Dolphins (Short-Beaked and Long-Beaked)

    Short-beaked common dolphins are the most abundant cetacean off 
California and are widely distributed between the coast and at least 
300 nautical miles (nmi; 555.6 km) offshore. In contrast, long-beaked 
common dolphins generally occur within 50 nmi of shore. Both stocks of 
common dolphin appear to shift their distributions seasonally and 
annually in response to oceanographic conditions and prey availability 
(Carretta et al., 2016). Long-beaked common dolphins appear to prefer 
shallower, warmer waters as compared to the short-beaked common dolphin 
(Perrin 2009). Both tend to be more abundant in coastal waters during 
warm-water months (Bearzi, 2005).
    The occurrence of common dolphins inside San Diego Bay is uncommon 
(NAVFAC SW and POSD, 2013). However, common dolphins were observed 
within the bay on three occasions (twelve, five, and two individuals) 
on two separate days during monitoring conducted during the Indicator 
Pile Program in Fall 2014 (78 FR 44539, July 24, 2013). 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)). Furthermore, it is unlikely that observers would be able 
to differentiate the specific species in the field.

California Sea Lion

    The California sea lion is by far the most commonly-sighted 
pinniped species in the vicinity of Naval Base Point Loma and northern 
San Diego Bay. California sea lions regularly occur on rocks, buoys and 
other structures, and especially on bait barges, although numbers vary 
greatly.
    Different age classes of California sea lions are found in the San 
Diego region throughout the year (Lowry et al., 1992), although Navy 
surveys show that the local population comprises adult females and sub-
adult males and females, with adult males being uncommon. The Navy has 
conducted marine mammal surveys throughout the north San Diego Bay 
project area (Merkel and Associates, 2008; Johnson, 2010, 2011; Lerma, 
2012, 2014). Sightings include all animals observed and their 
locations. The majority of observations are of animals hauled out.
    There are a few man-made areas near the proposed project site where 
California sea lions are known to haul out. The Navy has noted that the 
most proximal location is two sets of Navy-owned docks that are 140 m 
(459 ft) to the southwest and 180 m (591 ft) to the north. However, 
these docks are used constantly for other Navy activities and 
California sea lions are not expected to remain present for long 
periods of time. The Everingham Brother Bait Barges, located 
approximately 400 to 500 m (1,312 to 1,640 ft) southeast of the 
proposed project area, also serves as a known haul out site. No natural 
haul outs are known near the project site.
    Per NMFS's 2019 Pacific SAR, it is estimated that the carrying 
capacity for California sea lions is around 275,298 animals in 2014 
(Laake et al., 2018; Carretta et al., 2020a). As indicated by the 
current draft 2020 Pacific SAR, this estimate has not changed (Carretta 
et al., 2020b).

Harbor Seal

    Harbor seals are considered abundant throughout most of their range 
from Baja California to the eastern Aleutian Islands. Peak numbers of 
harbor seals haul-out on land during late May to early June, which 
coincides with the peak of their molt. Harbor seals do not make 
extensive pelagic migrations, but do travel hundreds of km on occasion 
to find food or suitable breeding areas (Carretta et al., 2016). Based 
on likely foraging strategies, Grigg et al., (2009) reported seasonal 
shifts in harbor seal movements based on prey availability. In 
relationship to the entire California stock, harbor seals do not have a 
significant mainland California distribution south of Point Mugu.
    Harbor seals are relatively uncommon within San Diego Bay. 
Sightings in the Navy transect surveys of northern San Diego Bay 
through March 2012 were limited to the south side of Ballast Point 
(TDI, 2012; Jenkins, 2012). However, Navy marine mammal monitoring for 
another project conducted intermittently at Pier 122 (located 
approximately 6,150 m (20,177.17 ft) northeast from the location of 
this proposed project) from 2010-2014 documented from zero to 4 harbor 
seals within the proposed project area at various times, with the 
greatest number of sightings during April and May (Jenkins, 2012; 
Bowman, 2014). Subsequently, monitoring conducted by the Navy during 
Year 1 of the fuel pier project documented increased numbers of harbor 
seals in the project area (Lerma, 2014). Approximately three-

[[Page 38280]]

quarters of these observations were of animals hauled out along the 
Naval Base Point Loma shoreline. An individual harbor seal was also 
frequently sighted near Naval Mine and Anti-Submarine Warfare Command 
(NMAWC), located approximately 3,700 m (12,139.11 ft) north of the 
project site, during 2014 (McConchie, 2014).

Northern Elephant Seal

    The population is estimated to have grown at 3.8 percent annually 
since 1988 (Lowry et al., 2014). Northern elephant seals breed and give 
birth in California (U.S.) and Baja California (Mexico), primarily on 
offshore islands. Populations of northern elephant seals in the U.S. 
and Mexico have recovered after being reduced to near extinction by 
hunting, undergoing a severe population bottleneck and loss of genetic 
diversity with the population reduced to only an estimated 10-30 
individuals.
    Northern elephant seals occur in the southern California bight, and 
have the potential to occur in San Diego Bay (NAVFAC SW and POSD 2013), 
but the only recent documentation of occurrence was of a single 
distressed juvenile observed on the beach south and inshore of the Fuel 
Pier during the second year IHA. 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. Current data indicate that 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) recommended that marine mammals be 
divided into functional hearing groups based on directly measured or 
estimated hearing ranges on the basis of available behavioral response 
data, audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. 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 dB 
threshold from the normalized composite audiograms, with the exception 
for lower limits for low-frequency cetaceans where the lower bound was 
deemed to be biologically implausible and the lower bound from Southall 
et al., (2007) retained. Marine mammal hearing groups and their 
associated hearing ranges are provided in Table 2.

           Table 2--Marine Mammal Rearing Groups (NMFS, 2018)
------------------------------------------------------------------------
           Hearing group                Generalized hearing range \1\
------------------------------------------------------------------------
Low-frequency (LF) cetaceans        7 Hz to 35 kHz.
 (baleen whales).
Mid-frequency (MF) cetaceans        150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans       275 Hz to 160 kHz.
 (true porpoises, Kogia, river
 dolphins, cephalorhynchid,
 Lagenorhynchus cruciger & L.
 australis).
Phocid pinnipeds (PW) (underwater)  50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW)              60 Hz to 39 kHz.
 (underwater) (sea lions and fur
 seals).
------------------------------------------------------------------------
\1\ 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. 
Six marine mammal species (three cetaceans and three pinnipeds (one 
otariid (California sea lion) and two phocid (harbor seal and Northern 
elephant seal) species have the reasonable potential to co-occur with 
the proposed construction activities (Table 1). Of the cetacean species 
that may be present at Naval Base Point Loma during this proposed 
project, none are classified as low-frequency cetaceans, three are 
classified as mid-frequency cetaceans (Pacific white-sided dolphins, 
bottlenose dolphins, and common dolphins), and none are classified as 
high-frequency cetaceans.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation, Monitoring, and 
Reporting Measures section, to draw conclusions regarding the likely 
impacts of these activities on the reproductive success or survivorship 
of individuals and how those impacts on individuals are likely to 
impact marine mammal species or stocks.
    Acoustic effects on marine mammals during the specified activity 
can occur from vibratory pile removal, the use of underwater chainsaws, 
pile clippers (individual and concurrently), and diamond wire saws. 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. However, Level A harassment is not expected 
nor would be authorized for this project.

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,

[[Page 38281]]

fish, and invertebrates), and anthropogenic sound (e.g., vessels, 
dredging, aircraft, construction).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity 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 this project would 
include vibratory pile removal as well as diamond wire saw, underwater 
chainsaws, and single-use or concurrent-use of pile clippers. The 
sounds produced by these activities fall into one of two general sound 
types: Impulsive and non-impulsive. Impulsive sounds (e.g., explosions, 
gunshots, 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; 
ANSI, 2005; NMFS, 2018). Non-impulsive sounds (e.g., machinery 
operations such as drilling or dredging, vibratory pile driving, 
chainsaws, pile clippers, 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 in Southall et 
al., 2007).
    Vibratory hammers would be used in this project. Vibratory hammers 
install or remove piles by vibrating them and allowing the weight of 
the hammer to push them into the sediment. Vibratory hammers produce 
significantly less sound than impact hammers. Peak Sound pressure 
Levels (SPLs) may be 180 dB or greater, but are generally 10 to 20 dB 
lower than SPLs generated during 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).
    Pile clippers, diamond wire saws, and underwater chainsaws are 
hydraulically operated equipment. A pile clipper is a large, heavy 
elongated horizontal guillotine-like structure that is mechanically 
lowered over a pile down to the mudline or substrate where hydraulic 
force is used to push a sharp blade to cut a pile. The underwater 
chainsaws are operated by SCUBA divers. The diamond wire saw may need 
to be operated by a SCUBA diver as well. Sounds generated by this 
demolition equipment are non-impulsive and continuous (NAVAC SW, 2020).
    The likely or possible impacts of the Navy's proposed activity on 
marine mammals could result from exposure to both non-acoustic and 
acoustic stressors. Potential non-acoustic stressors could include 
physical presence of the equipment and personnel; however, impacts to 
marine mammals are expected to primarily be acoustic in nature. 
Acoustic stressors include noise generated from heavy equipment 
operation during pile removal.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile removal and the various demolition equipment is 
the primary means by which marine mammals may be harassed from the 
Navy's specified activity. 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 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 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 removal 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. mom with calf), duration of exposure, the 
distance between the pile and the animal, received levels, behavior at 
time of exposure, and previous history with exposure (Wartzok et al., 
2004; Southall et al., 2007). Here we discuss physical auditory effects 
(threshold shifts) followed by behavioral effects and potential impacts 
on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the likelihood or consequence of TS, 
including, but not limited to, the signal temporal pattern (e.g., 
impulsive or non-impulsive), likelihood an individual would be exposed 
for a long enough duration or to a high enough level to induce a TS, 
the magnitude of the TS, time to recovery (seconds to minutes or hours 
to days), the frequency range of the exposure (i.e., spectral content), 
the hearing and vocalization frequency range of the exposed species 
relative to the signal's frequency spectrum (i.e., how animal uses 
sound within the frequency band of the signal; e.g., Kastelein et al., 
2014), and the overlap between the animal and the source (e.g., 
spatial, temporal, and spectral).
Permanent Threshold Shift (PTS)
    NMFS defines PTS as a permanent, irreversible increase in the 
threshold of audibility at a specified frequency or portion of an 
individual's hearing range above a previously established reference 
level (NMFS, 2018). Available data from humans and other terrestrial 
mammals indicate that a 40 dB threshold shift approximates PTS onset 
(see Ward et al., 1958, 1959; Ward, 1960; Kryter et al., 1966; Miller, 
1974; Ahroon et al., 1996; Henderson et al., 2008). PTS levels for 
marine mammals are estimates, and with the exception of a single study 
unintentionally inducing PTS in a harbor seal (Kastak et al., 2008), 
there are no empirical data measuring PTS in marine mammals, largely 
due to the fact that, for various ethical reasons, experiments 
involving anthropogenic noise exposure at levels

[[Page 38282]]

inducing PTS are not typically pursued (NMFS, 2018).
Temporary Threshold Shift (TTS)
    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 (Phocoena phocoena), 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). 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. For summaries of data on TTS in marine mammals or for 
further discussion of TTS onset thresholds, please see Southall et al. 
(2007), Finneran and Jenkins (2012), Finneran (2015), and Table 5 in 
NMFS (2018).
    During pile removal activities there would likely be pauses in the 
activities producing sound during each day. Given these pauses and that 
many marine mammals are likely moving through the action area and not 
remaining for extended periods of time, the potential for TS declines.
Behavioral Harassment
    Exposure to noise from pile 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); 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). 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.
    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). 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, when 
available, may be used to better inform assessment of whether foraging 
disruptions are likely to have fitness consequences.
    In 2016, the Alaska Department of Transportation and Public 
Facilities (ADOT&PF) documented observations of marine mammals during 
construction activities (i.e., pile driving) at the Kodiak Ferry Dock 
(ABR, 2016; see 80 FR 60636, October 7, 2015). In the marine mammal 
monitoring report for that project (ABR, 2016), 1,281 Steller sea lions 
were observed within the Level B harassment disturbance zone during 
pile driving or drilling (i.e., documented as Level B harassment

[[Page 38283]]

take). Of these, 19 individuals demonstrated an alert behavior, 7 were 
fleeing, and 19 swam away from the project site. All other animals (98 
percent) were engaged in activities such as milling, foraging, or 
fighting and did not change their behavior. In addition, two sea lions 
approached within 20 m of active vibratory pile driving activities. 
Three harbor seals were observed within the disturbance zone during 
pile driving activities; none of them displayed disturbance behaviors. 
Fifteen killer whales (Orcinus orca) and three harbor porpoise were 
also observed within the Level B harassment zone during pile driving. 
The killer whales were travelling or milling while all harbor porpoises 
were travelling. No signs of disturbance were noted for either of these 
species. Given the similarities in activities and habitat, we expect 
similar behavioral responses of marine mammals to the Navy's specified 
activity. That is, disturbance, if any, is likely to be temporary and 
localized (e.g., small area movements).
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 would 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 
(Eubalaena glacialis). These and other studies lead to a reasonable 
expectation that some marine mammals would 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 
this project 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 
San Diego area contains active military and commercial shipping, cruise 
ship and ferry operations, as well as numerous recreational and other 
commercial vessel and background sound levels in the area are already 
elevated as described in Dahl and Dall'Osta (2019).

Potential Effects of Diamond Wire Saw, Underwater Chainsaw, and Single 
or Concurrent Use of Pile Clipper Sounds

    Diamond wire saws, underwater chainsaws, and pile clippers may be 
used to assist with removal of piles. The sounds produced by these 
activities are of similar frequencies to the sounds produced by vessels 
(NAVFAC SW, 2020), and are anticipated to diminish to background noise 
levels (or be masked by background noise levels) in the Bay relatively 
close to the project site. Therefore, the effects of this equipment are 
likely to be similar to those discussed above in the Behavioral 
Harassment section.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile 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

[[Page 38284]]

relation to underwater sound. For instance, anthropogenic sound could 
cause hauled-out pinnipeds to exhibit changes in their normal behavior, 
such as reduction in vocalizations, or cause them to temporarily 
abandon the area and move further from the source. However, these 
animals would previously have been `taken' because of exposure to 
underwater sound above the behavioral harassment thresholds, which are 
in all cases 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.

Potential Effects on Marine Mammal Habitat

    The Navy's construction activities could have localized, temporary 
impacts on marine mammal habitat and their 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 
area (see discussion below). During vibratory pile removal or pile 
cutting, elevated levels of underwater noise would ensonify San Diego 
Bay 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 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 
removed. In general, turbidity associated with pile installation is 
localized to about a 25-foot (7.6-meter) radius around the pile 
(Everitt et al., 1980). The sediments of the project site are sandy and 
would settle out rapidly when disturbed. Cetaceans are not expected to 
be close enough to the pile removal areas to experience effects of 
turbidity, and any pinnipeds could avoid localized areas of turbidity. 
Local strong 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.
    The area likely impacted by the project is relatively small 
compared to the available habitat (e.g., the impacted area is in the 
Bay mouth only) of San Diego Bay and does not include any Biologically 
Important Areas or other habitat of known importance. The area is 
highly influenced by anthropogenic activities. The total seafloor area 
affected by pile removal is a very small area compared to the vast 
foraging area available to marine mammals in the San Diego Bay. At 
best, the impact area provides marginal foraging habitat for marine 
mammals and fish. Furthermore, pile removal at the project site would 
not obstruct 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 avoidance of this area after pile removal stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity due to temporary 
species displacement.

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). 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, although several are 
based on studies in support of large, multi-year bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). Several 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). 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; Cott 
et al., 2012).
    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).
    Because of the rarity of use and research, the effects of pile 
clippers, diamond wire saws, underwater chainsaws, and water jetting 
are not fully known; but given their similarity to ship noises we do 
not expect unique effects from these activities.
    The most likely impact to fish from pile removal activities at the 
project area would be temporary behavioral avoidance of the area. The 
duration of fish avoidance of this area after pile driving stops is 
unknown, but a rapid

[[Page 38285]]

return to normal recruitment, distribution and behavior is anticipated.
    Construction activities, in the form of increased turbidity, have 
the potential to adversely affect forage fish in the project area. 
Forage fish form a significant prey base for many marine mammal species 
that occur in the project area. Increased turbidity is expected to 
occur in the immediate vicinity (on the order of 10 feet (3 m) or less) 
of construction activities. However, suspended sediments and 
particulates are expected to dissipate quickly within a single tidal 
cycle. Given the limited area affected and high tidal dilution rates 
any effects on forage fish are expected to be minor or negligible. 
Finally, exposure to turbid waters from construction activities is not 
expected to be different from the current exposure; fish and marine 
mammals in San Diego Bay are routinely exposed to substantial levels of 
suspended sediment from natural and anthropogenic sources.
    In summary, given the short daily duration of sound associated with 
individual pile removal events and the relatively small areas being 
affected, pile removal activities associated with the proposed action 
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 areas of fish and 
marine mammal foraging habitat in the nearby vicinity. Thus, we 
conclude that impacts of the specified activity 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 would inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would be by Level B harassment only, in the form 
of disruption of behavioral patterns and TTS for individual marine 
mammals resulting from exposure to the sounds produced from the 
underwater acoustic sources (i.e., vibratory hammer, single use or 
concurrent use of pile clippers, underwater chainsaw, diamond wire 
saw). Based on the nature of the activity and the anticipated 
effectiveness of the mitigation measures (i.e., PSO monitoring and 
shutdown zone) discussed in detail below in the Proposed Mitigation, 
Monitoring, and Reporting Measures section, Level A harassment is 
neither anticipated nor proposed to be authorized.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals would be behaviorally harassed or incur some 
degree of permanent hearing impairment; (2) the area or volume of water 
that would be ensonified above these levels in a day; (3) the density 
or occurrence of marine mammals within these ensonified areas; and, (4) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of 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 
estimate.

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 for non-explosive sources--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 (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 [mu]Pa (root mean square (rms)) for 
continuous (e.g., vibratory hammer) and above 160 dB re 1 [mu]Pa (rms) 
for non-explosive impulsive (e.g., impact hammers (pile-driving)) or 
intermittent (e.g., scientific sonar) sources.
    The Navy's pile removal activities includes the use of stationary, 
non-impulsive, and continuous noise sources (vibratory hammer, diamond 
wire saw, underwater chainsaw, single use or concurrent use of pile 
clippers), and therefore the 120 dB re 1 [mu]Pa (rms) is applicable. 
However, as discussed above, the Navy measurements support an ambient 
noise estimate of 129.6 dB re 1 [mu]Pa (rms) in the project area. 
Accordingly, we have adjusted the standard Level B harassment threshold 
of 120 dB to 129.6 dB, as it likely provides a more realistic and 
accurate basis for predicting Level B harassment in the San Diego Bay 
area.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (NMFS, 2018a) 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 pile removal activities includes the use of non-impulsive 
(vibratory pile removal and other cutting and removal methods) sources.
    These thresholds are provided in Table 3 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018a Technical Guidance, which may be accessed at 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

[[Page 38286]]



                  Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift (PTS)
----------------------------------------------------------------------------------------------------------------
                                                    PTS onset acoustic thresholds \1\ (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
\1\ Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1 [mu]Pa2s. In this Table, thresholds are abbreviated to reflect American National
  Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
  frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
  being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
  designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
  that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
  exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
  is valuable for action proponents to indicate the conditions under which these acoustic thresholds would be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that would feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels, durations, and 
transmission loss coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., vibratory pile removal, 
diamond wire saw, single use or concurrent use of pile clippers, and 
underwater chainsaws).
    Vibratory hammers produce constant sound when operating, and 
produce vibrations that liquefy the sediment surrounding the pile, 
allowing it to penetrate to the required seating depth or be withdrawn 
more easily. The actual durations of each method vary depending on the 
type and size of the pile.
    In order to calculate the distance to the Level B harassment sound 
threshold for piles of various sizes being used in this project, the 
Navy used acoustic monitoring data from other locations and projects to 
develop source levels for the various pile types, sizes, and methods of 
removal. Data for the removal methods (i.e., a diamond wire saw, 
individual use or concurrent use of pile clippers, and an underwater 
chainsaw) comes from data gathered at other nearby or related Navy 
projects as reported in their San Diego Noise Compendium (NAVFAC SW, 
2020). The only exception to this would be the sound source data for 
the vibratory hammer, which was sourced from the City of Seattle Pier 
62 project (Greenbusch Group, 2018). The source levels for the pile 
clippers, single and simultaneous use, and underwater chainsaw for this 
project utilized the mean maximum RMS SPL rather than the median sound 
levels we typically use as this would provide a more conservative 
measure. The diamond wire saw utilized the noise profile measurements 
associated with the removal of 66-inch and 84-inch caissons in the Navy 
Compendium (NAVFAC SW, 2020).). The Navy has noted, and we agree, that 
these values are likely much lower in reality as this proposed project 
would remove 16-inch concrete piles instead of the much larger varients 
modeled in the Compendium. However, no recorded data currently exists 
for the wire saws cutting concrete; therefore, we used the mean of the 
source level data from the Navy Compendium. The vibratory hammer used 
the highest average weighted RMS sound level per the Seattle Pier 62 
project acoustic monitoring report (Greenbusch Group, 2018).
    During pile removal activities, there may be times when two pile 
extraction methods (i.e., pile clippers) are used simultaneously. The 
likelihood of such an occurrence is anticipated to be infrequent, would 
depend on the specific methods chosen by the contractor, and would be 
for short durations on that day. In-water pile removal occurs 
intermittently, and it is common for removal to start and stop multiple 
times as each pile is adjusted and its progress is measured. Moreover, 
the Navy has multiple options for pile removal depending on the pile 
type and condition, sediment, and how stuck the pile is, etc. When two 
continuous noise sources, such as pile clippers, have overlapping sound 
fields, there is potential for higher sound levels than for non-
overlapping sources. When two or more pile removal methods (pile 
clippers) are used simultaneously, and the sound field of one source 
encompasses the sound field of another source, the sources are 
considered additive and combined using the following rules (see Table 
4). For addition of two simultaneous methods, the difference between 
the two sound source levels (SSLs) is calculated, and if that 
difference is between 0 and 1 dB, 3 dB are added to the higher SSL; if 
difference is between 2 or 3 dB, 2 dB are added to the highest SSL; if 
the difference is between 4 to 9 dB, 1 dB is added to the highest SSL; 
and with differences of 10 or more dB, there is no addition (NMFS, 
2018b; WSDOT, 2018).

 Table 4--Rules for Combining Sound Levels Generated During Pile Removal
------------------------------------------------------------------------
                               Level A harassment    Level B harassment
      Difference in SSL             isopleths             isopleths
------------------------------------------------------------------------
0 or 1 dB...................  Add 3 dB to the       Add 3 dB to the
                               higher source level.  higher source
                                                     level.
2 or 3 dB...................  Add 2 dB to the       Add 2 dB to the
                               higher source level.  higher source
                                                     level.
4 to 9 dB...................  Add 1 dB to the       Add 1 dB to the
                               higher source level.  higher source
                                                     level.

[[Page 38287]]

 
10 dB or more...............  Add 0 dB to the       Add 0 dB to the
                               higher source level.  higher source
                                                     level.
------------------------------------------------------------------------
Source: Modified from USDOT, 1995; WSDOT, 2018; and NMFS, 2018b.
Note: dB = decibel; SSL = sound source Level

Level A Harassment Zones

    When the NMFS Technical Guidance (2016) was published, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of Level A harassment take. However, these tools offer the 
best way to predict appropriate isopleths when more sophisticated 3D 
modeling methods are not available, and NMFS continues to develop ways 
to quantitatively refine these tools, and will qualitatively address 
the output where appropriate. For stationary sources, such as the 
localized pile removal activities discussed above, the NMFS User 
Spreadsheet predicts the distance at which, if a marine mammal remained 
at that distance the whole duration of the activity, it would incur 
PTS.
    The Navy provided estimates to NMFS for the duration of sound 
exposure for each pile removal activity. The durations used in this 
proposed project for each pile removal method were noted as 
``conservative estimates that are greater than durations observed in 
the San Diego Noise Compendium'' by the Navy. In discussions with NMFS, 
the Navy has explained that the average durations found in the IHA 
application and Compendium were based around data collected in the from 
the old Fuel Pier demolition projects (NAVFAC SW 2014, 2015a, 2016, 
2017a, 2017b, 2018a, and 2018b). These values were adjusted to account 
for either the maximum amount of time the activity could occur (i.e., 
pile clippers), a duration that is greater than the maximum (i.e., 
underwater chainsaw and vibratory hammer), or an adjusted duration 
based on the removal of a smaller pile (i.e., diamond wire saw) in 
order to provide somewhat more conservative measurements using real-
world data. These values were likely considered more realistic for past 
projects and could safely be assumed as conservative for this proposed 
project as the Navy will be cutting smaller sized piles. The Navy also 
performed an ``ultra-conservative'' hypothetical review by modeling a 
1-hour duration for each pile being removed. Using a rate of five piles 
removed per day, the resulting Level A harassment isopleths were still 
smaller than the 20 m shutdown zone the Navy plans to implement. 
Further information on durations can be found in the Compendium (NAVFAC 
SW, 2020).
    All inputs used in the User Spreadsheet are reported below in Table 
5.

                        Table 5--Project Sound Source Levels and User Spreadsheet Inputs
----------------------------------------------------------------------------------------------------------------
                                                                                    Duration of
                                                                   Source level        sound       Transmission
             Activity \3\                    Type of source        (dB RMS) \1\     production         loss
                                                                                    (hours) \2\     coefficient
----------------------------------------------------------------------------------------------------------------
Vibratory pile driving................  Stationary source, non-              152          0.1667              15
                                         impulsive, continuous.
13-inch polycarbonate pile removal....  Stationary source, non-              154            0.42            11.7
                                         impulsive, continuous.
16-inch concrete pile removal.........  Stationary source, non-              147            0.42              15
                                         impulsive, continuous.
16-inch concrete pile clipping with     Stationary source, non-              150            0.42              15
 +3dB adjustment for two simultaneous    impulsive, continuous.
 pile clippers.
16-inch concrete pile removal using     Stationary source, non-              150            0.83              15
 hydraulic chainsaw (underwater          impulsive, continuous.
 chainsaw).
Wire saw for caisson cutting..........  Stationary source, non-              156             1.7              15
                                         impulsive, continuous.
----------------------------------------------------------------------------------------------------------------
\1\ All of these sound source data for use in the Level A and B harassment threshold modeling were calculated
  from acoustic data found in the 2020 San Diego Noise Compendium (NAVFAC SW, 2020); the only exception is the
  vibratory hammer source level which was sourced from the City of Seattle Pier 62 Project (Greenbusch Group,
  2018).
\2\ The User Spreadsheet inputs assumed 5 piles would be removed within a single 24-hour period using data from
  the Navy's Compendium (NAVFAC SW, 2020).
\3\ All activities utilized a weighting factor adjustment (kHz) of 2.5.

    For this project, we modeled sound propagation using the practical 
spreading value of 15 for transmission loss for all pile removal 
methods, except for the removal of the 13-inch polycarbonate piles. For 
this, 11.7 was used as the transmission loss coefficient as this value 
was a calculated measure from recorded data that was fit with a 
logarithmic trendline during the clipping of a 13-inch round concrete 
pile using small pile clippers in February 2017 at the old Fuel Pier 
(NAVFAC SW, 2020). The above input scenarios lead to PTS isopleth 
distances (Level A harassment thresholds) of less than 1 meter for all 
methods and piles (Table 6).

[[Page 38288]]



           Table 6--Modeled and Expected Level A and B Harassment Isopleths (Using Two Methods) for the Pile Type and Removal Method (Meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           (A) Projected distances to level A harassment    (B) Projected distances to
                                                                                           isopleth \3\                     level B harassment isopleth
                                                                         ------------------------------------------------               \5\
             Pile information                      Removal method                                                        -------------------------------
                                                                                                                             Practical
                                                                                MF              PW              OW        spreading loss  Real-time data
                                                                                                                               model
--------------------------------------------------------------------------------------------------------------------------------------------------------
13-inch polycarbonate pile................  One pile clipper............             0.0             0.0             0.0         \5\ 423             350
14-inch, 16-inch concrete piles...........  One pile clipper............             0.0             0.0             0.0             145         \5\ 250
14-inch, 16-inch concrete pile \1\........  Two pile clippers...........             0.0             0.0             0.0             229         \5\ 250
14-inch, 16-inch concrete pile............  Underwater chainsaw.........             0.0             0.1             0.0         \5\ 229              45
14-inch, 16-inch concrete pile............  Diamond wire saw............             0.1             0.7             0.0         \5\ 575             350
14-inch, 16-inch concrete pile............  Vibratory hammer............             0.1             0.9             0.1         \5\ 311           (\4\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
MF = mid-frequency cetaceans, PW = phocid pinnipeds, OW = otariid pinnipeds.
\1\ The Navy added an adjustment of +3 dB to the noise of a single pile clipper (147 dB RMS re 1[mu]Pa) and increased to 150 dB RMS re 1[mu]Pa where two
  clippers are used simultaneously (Kinsler et al., 2000). This adjustment is consistent with NMFS guidance for simultaneous sound sources.
\2\ All sound sources were taken from the Compendium of Underwater and Airborne Sound Data during Pile Installation and In-Water Demolition Activities
  in San Diego Bay, California (San Diego Noise Compendium; NAVFAC SW, 2020), with exception of the vibratory hammer which was sourced from the City of
  Seattle Pier 62 Project (Greenbusch Group, 2018).
\3\ Because of the small sizes of the Level A harassment isopleths (as determined by NMFS's User Spreadsheet Tool) and the mitigation methods
  implemented during this project, neither NMFS nor the Navy expects Level A harassment (and, therefore, take) to occur.
\4\ No information available.
\5\ Designate the most conservative isopleths NMFS will use for the subsequent Level B take analyses and Level B harassment impact zones.

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's proposed activity in the absence of specific 
modeling. We used the Navy's realistic, site-specific averaged median 
ambient noise measurement of 129.6 dB RMS re 1 [mu]Pa for the Level B 
harassment threshold in San Diego Bay (NAVFAC SW, 2020). It should be 
noted that based on the bathymetry and geography of San Diego Bay, 
sound would not reach the full distance of the Level B harassment 
isopleths in all directions.
    To determine the most appropriate and conservative Level B 
harassment isopleths, we compared two methods and selected the isopleth 
between each method that was largest, thus providing the greatest 
coverage for the Level B harassment zone. Level B harassment isopleths 
were considered appropriate based on the distance where the source 
level reached the 129.6 dB ambient value. The two methods compared the 
empirical data provided in the Navy's Compendium for work at Naval Base 
Point Loma (NAVFAC SW, 2020) with the Practical Spreading Loss model 
using a transmission loss coefficient of 15, as described above. 
Results of each method are shown in Table 6 and described below.
    For the Compendium method, the average and maximum sound levels (in 
dB re 1 [micro]Pa) measured at the source (10 m) and then at various 
far-field distances typically showed a monotonic decline in average and 
maximum sound pressure levels asas distance increased. The Navy chose 
to use the average values for two main reasons: (1) Consistency with 
using the average median (L50) ambient values; and (2) average source 
values were used for the same activities in the Pier 6 project nearby 
(86 FR 7993, February 3, 2021). However, some level of variability in 
the recorded sound pressure levels was present where noise levels would 
drop to ambient levels and then increase to higher levels at greater 
distances. An example of this would be measurements for the 84-inch 
caisson removal by a single wire saw. At source (10 m), the average and 
maximum source levels exceeded the ambient noise levels for both 
measurements at the source (136.1 and 141.4 dB re 1 [micro]Pa; 140.9 
and 146.5 dB re 1 [micro]Pa, respectively). At far-field distances (>20 
m), the averages show variability with a gradual decline and then a 
subsequent increase, i.e., 140.8 dB re 1 [micro]Pa at 20 m and 134.8 at 
40 m, then 137.1 dB re 1 [micro]Pa at 60 m. The distance where sound 
was measured ends at 283 m from the source with an average level of 
130.3 dB re 1 [micro]Pa and a maximum level of 137.0 dB re 1 [micro]Pa, 
both in exceedance of the ambient level. These instances could be 
attributed to the presence of vessel traffic at distance from the 
acoustic recorder, causing some interference or competing background 
noise to the pure sound measurements of the wire saw or to random 
variation from other acoustic effects related to the specific location 
of the hydrophone. In any event, the distance at which the sound 
declined below ambient was not always entirely clear and the Navy was 
unable to develop a consistent criterion to determine the likely 
distance at which sound decreased below ambient or to account for 
factors like the topography or hydrophone location. Therefore we 
describe the analysis of the Navy

[[Page 38289]]

Compendium's field data for each pile removal method individually 
below.
    For the 13-inch polycarbonate piles with pile clippers the Navy 
believes that at between 300 and 400 m (984 to 1,312 ft), a majority of 
the background noise measured is directly related to traffic transiting 
to/from the Everingham Brothers Bait Company (EBBCO) bait barges which 
are to the southwest of the project area. Boat traffic for that 
specific route ranges from small boats to large recreational/commercial 
fishing vessels and traffic is nearly constant throughout the day. 
Because of that, the Navy believes values between those distances would 
likely be artificially high relative to the transmission loss 
associated with the project-related activities. Furthermore, with the 
turning basin (see Figure 2), the slope rises up from a max depth of 
20.12 m (66 ft) to 11.58 m (38 ft) between 200 to 400 m (656.17 to 
1,312.34 ft). As is evidenced by the Navy's acoustical model for south-
central San Diego Bay (see the Naval Base Point Loma Pier 6 project at 
https://www.fisheries.noaa.gov/action/incidental-take-authorization-naval-base-san-diego-pier-6-replacement-project-san-diego), changes in 
bathymetry (i.e., channel walls) act as noise attenuators. Therefore, 
the Navy estimated the Level B harassment isopleth for this source at 
350 m, smaller than the Practical Spreading Loss model prediction of 
423 m. Given the uncertainty discussed above, we used the 423 m 
distance for the Level B harassment isopleth.
[GRAPHIC] [TIFF OMITTED] TN20JY21.002

    For the one pile clipper on concrete pile source, the Navy again 
believes the Compendium data were influenced by boat activity and 
topography of the channel. In this particular case, Table 39 of the 
Compendium shows that the average dB level at 215 m was 129.0 dB RMS. 
However, the two measurements at 309 m were split, one higher and one 
lower than the value at 215 m. The Navy decided that ``Understanding 
that acoustics is not an ``exact science,'' we evaluated the data and 
chose a distance (250 m) that fit the data (average noise levels 
dropped below 129.6 dB at between 215 and 309 m).'' As this 250 m 
distance exceeded the practical spreading loss model distance of 145 m, 
we chose the 250 m distance for the Level B harassment isopleth.
    For the two pile clipper on concrete pile source the Navy decided 
that ``Because the project footprint is parallel to the shoreline, we 
created a monitoring zone that used a source level of 150 dB, but at 
two points at the extreme north and south of the project footprint (see 
Fig 6-3 in the IHA application) because we felt that this would 
generate a more conservative'' zone that led to an estimate of the 
Level B harassment isopleth of 250 m. As this 250 m distance exceeded 
the practical spreading loss model distance of 229 m, we chose the 250 
m distance for the Level B harassment isopleth.
    For the underwater chainsaw the Navy noted the ``transmission loss 
(27logR) was steep when compared to other equipment, but the source 
value was in line with the pile clippers. Because of the very steep TL 
value, we looked at the perceived far-field data points for the clipper 
activities and chose a distance that was in-between the drop off to 
ambient for the chainsaw (from 26 to 45 m) and the clippers (250 m).'' 
The Navy estimated the Level B harassment isopleth for this source at 
45 m, smaller than the Practical Spreading Loss model prediction of 229 
m. Given the uncertainty discussed above, we used the 229 m distance 
for the Level B harassment isopleth.
    For the diamond wire saw the Navy again believes the Compendium 
data were influenced by boat activity and topography of the channel. 
The available data are from caissons which consist of 1.5 inch thick 
hardened steel

[[Page 38290]]

shells filled with concrete, and with wooden piles in the center of the 
concrete. For lack of information on wire saws, the Navy evaluated the 
likely far-field values for the potential zones based on the 84-inch 
caissons (Table 34 in the Compendium), which had more data at multiple 
distances. The Navy ``felt that this was a valid approach based on the 
similarity of the average noise data at 40 m (132.5 dB for 66-inch 
caisson, 134.8 for the 84-inch caisson). Per Table 34, using the 
average dB values at distance, the data shows a drop below 129.6 dB RMS 
at 200 m, but a rise again at 283 m. If you plot the regression curve 
based on the average 84-inch data, we cross the ambient threshold at 
app[roximately] 350 m . . . Because the data at far-field distances was 
variable, we chose a monitoring zone (350 m) that was based on the 
available real-time data. . . . Our assumption is that, if a wire saw 
were to be used on the concrete piles, the noise levels would be lower 
than either the 66- or 84-inch caisson.'' The Navy estimated the Level 
B harassment isopleth for this source at 350 m, smaller than the 
Practical Spreading Loss model prediction of 575 m. Given the 
uncertainty discussed above, we used the 575 m distance for the Level B 
harassment isopleth.

Marine Mammal Occurrence, Take Calculation, and Take Estimation

    In this section, we provide the information about the presence, 
density, or group dynamics of marine mammals that would inform the take 
calculations. Here we describe how the information provided above is 
brought together to produce a quantitative take estimate.
    We examined two approaches towards estimating the Level B take for 
the requested six marine mammal species within the project area at 
Naval Base Point Loma. The first approach was using our standard 
approach of using species density multiplied by isopleth size. The 
second approach utilized daily sightings from monitoring reports 
produced from past Navy projects at Naval Base Point Loma (NAVFAC SW, 
2015a; NACFAC SW, 2017; NAVFAC SW, 2018).
    Density estimates for any specific area assumes that the species' 
in question are evenly distributed across the entire site, which is 
rarely the case. Using the first approach for this project, we examined 
the use of densities, using an overall density for San Diego Bay, 
within a much smaller and definitive area (specifically Naval Base 
Point Loma). This approach, in combination with the predicted Level B 
harassment isopleths, yielded take estimates that were determined to 
not be conservative enough in nature for these proposed activities and 
activity source levels as compared to the results of the in situ 
measurements included in the Navy's Compendium (NAVFAC SW, 2020) and as 
discussed above. Furthermore, the take estimates produced from this 
method did not appropriately account for group size of all marine 
mammal species as the density estimate was for a much larger area 
(consisting of a primarily offshore environment) and assumed a much 
larger spread of marine mammals. Therefore, this approach was not 
utilized and will not be discussed further.
    The second approach utilized average daily sightings from the Year 
1-5 monitoring reports from IHAs that were previously issued (NAVFAC 
SW, 2015a; NACFAC SW, 2017; NAVFAC SW, 2018). This information was 
provided by the Navy in Table 7.

                                        Table 7--Monitoring Results From the Navy's Years 1-5 Projects at Naval Base Point Loma in San Diego, California
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Year 1 project (10 days;    Year 2 project (100 days;   Year 3 project (59 days)    Year 4 project (152 days)   Year 5 project (49 days)
                                                       potential El Ni[ntilde]o      El Ni[ntilde]o year)    -----------------------------------------------------------------------------------
                                                                 year)           ----------------------------
                       Species                       ----------------------------                                                Average                     Average                     Average
                                                                         Average           Average/  Average   Total   Average/   group    Total   Average/   group    Total   Average/   group
                                                       Total   Average/   group    Total      day     group               day      size               day      size               day      size
                                                                  day      size                        size
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lions................................    2,229     229.9      2.2    7,507      75.1      1.4      483       8.2      1.3    2,263    * 14.9      1.7      618      12.6      1.3
Harbor seal.........................................       25       2.5      1.1      248       2.5      1.0       25       0.4      1.0       88     * 0.6      1.1       28       0.6      1.0
Bottlenose dolphins.................................       83       8.3      2.4      695       7.0      2.8       25       0.4      1.9       67     * 0.4      2.7       13       0.3      2.2
Common dolphins.....................................       19        19      6.3      850     * 8.5      \2\      n/a       n/a      n/a      n/a       n/a      n/a      n/a       n/a      n/a
                                                                                                        42.5
Pacific white-sided dolphins........................      n/a       n/a      n/a       27     * 0.3      3.9      n/a       n/a      n/a      n/a       n/a      n/a      n/a       n/a      n/a
Northern elephant seals.............................      n/a       n/a      n/a    (\1\)     (\1\)    (\1\)      n/a       n/a      n/a      n/a       n/a      n/a      n/a       n/a      n/a
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* These estimates were chosen for the second method in which to estimate take of marine mammals for this proposed action.
\1\ Same individuals was observed hauled out on a beach twice.
\2\ This includes four sightings of groups of 100+ animals outside of San Diego Bay. When these observations are eliminated, the average group size is 6.75 animals observed inside of San Diego
  Bay.

    The Year 1 and 2 monitoring reports demonstrated marine mammal 
estimates during a potential and known El Ni[ntilde]o year, 
respectively. Because of this, these values were likely not 
representative of the typical conditions around Naval Base Point Loma 
and were not preferred.
    California sea lions, harbor seals, and bottlenose dolphins were 
recorded during all other years. Within these, Year 4 was considered 
the most conservative as these activities consisted of the longest 
duration (152 days) with the highest number of sightings for these 
species. So for these species we used the Year 4 average daily values.
    Pacific white-sided dolphins were only recorded during Year 2. 
While these estimates are likely not fully representative of the 
typical distributions of Pacific white-sided dolphins around San Diego 
Bay, they will serve as the basis for our conservative take estimates 
for this species. Common dolphins were observed in Years 1 and 2; 
however, the length of the project period in Year 2 (100 days) was 
considered more representative than the Year 1 project (10 days). 
Therefore, the values from the Year 2 estimates were used for common 
dolphins. A single Northern elephant seal was only recorded to have 
hauled out on a beach twice during all Year 1-5 work. Due to this, no 
average daily estimates were present for analysis; however, some 
discretionary take is proposed to be authorized in the event Northern 
elephant seals are present during this proposed action.
    For all species (excluding Northern elephant seals), these daily 
sightings were extrapolated over the number of days of pile removal 
activities (84).
    This second approach yielded larger and more conservative Level B 
take estimates, but more realistic for particular species occurrence 
and group size given the data was previously collected at the location 
of this proposed project for similar or the same species during past 
projects. Here we describe how the information provided

[[Page 38291]]

above is brought together to produce a quantitative take estimate.
    By following this daily occurrence-based approach using past 
sightings at Naval Base Point Loma, we would expect that 15 California 
sea lions, 1 harbor seal, 9 common dolphins, 1 Pacific white-sided 
dolphin, and 1 bottlenose dolphin would be sighted per day. 
Multiplication of the above daily occurrences times the number of pile 
removal days planned (84) results in the proposed Level B harassment 
take of 1,260 California sea lions, 84 harbor seals, 756 common 
dolphins, 84 Pacific white-sided dolphins, and 84 bottlenose dolphins 
(see Table 8 for final estimates).
    The Navy has noted that northern elephant seals are very rarely 
seen in this area, with the only true record being of a hauled out and 
distressed juvenile during the Year 2 IHA (NAVFAC SW, 2015a). As a 
precaution that a greater number of northern elephant seal may occur 
around Naval Base Point Loma, we propose to authorize seven Level B 
takes.

                     Table 8--Estimated Take Using the Past Sighting Approach for Each Species and Stock During the Proposed Project
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               Estimated
          Common  name              Scientific  name          Stock         sightings  per  Total  Level B take      Data  source      Percent  of stock
                                                                                  day          requested \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lion.............  Zalophus             U.S. Stock.........              15  1,260..............  NAVFAC SW (2017,     0.49.
                                   californianus.                                                                 2018).
Harbor seal.....................  Phoca vitulina.....  California Stock...               1  84.................  NAVFAC SW (2017,     0.27.
                                                                                                                  2018).
Northern elephant seal..........  Mirounga             California Breeding  ..............  \1\ 7..............  NAVFAC SW (2015a)..  0.00.
                                   angustirostris.      Stock.
Common dolphins (Short-beaked,    Delphinus sp. \3\..  California/Oregon/                9  756 (between both    NAVFAC SW (2015a)..  0.08 per SBCD
 long-beaked).                                          Washington Stock;                    species).                                 stock; 0.31 per
                                                        California Stock.                                                              LBCD stock.
Pacific white-sided dolphin.....  Lagenorhynchus       California/Oregon/                1  84.................  NAVFAC SW (2015a)..  0.31.
                                   obliquidens.         Washington--Northe
                                                        rn and Southern
                                                        Stocks.
Bottlenose dolphin..............  Tursiops truncatus.  California Coastal                1  84.................  NAVFAC SW (2017,     18.54.
                                                        Stock.                                                    2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Only recently documented near the project occurrence with one distressed individual hauled out on a beach inshore to the south during the second
  year of the previous Fuel Pier IHA (NAVFAC SW, 2015a). A conservative estimate of 2 was assumed with a +5 take buffer added.
\2\ These numbers were derived by multiplying the rounded average daily sightings by 84 days and then summed for the total requested Level B harassment
  take.
\3\ See discussion in the section on Common Dolphins (Short-beaked and Long-beaked) regarding the Society for Marine Mammalogy's Committee on Taxonomy
  decision (Committee on Taxonomy, 2020).

    By using the sighting-based approach, take values are not affected 
by the chosen isopleth sizes from Table 6.
    Given the very small Level A harassment isopleths for all species, 
no take by Level A harassment is anticipated or proposed for this 
authorization.

Proposed Mitigation, Monitoring, and Reporting Measures

    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, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure would be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The following mitigation measures are proposed in the IHA:
     All pile removal activities will occur individually, with 
the exception for the removal of the 14-inch and 16-inch concrete 
piles, which may be removed simultaneously by use of the pile clippers;
     A 20 m (66-ft) shutdown zone will be implemented around 
all pile removal activities (Table 9). If a marine mammal enters the 
shutdown zones, pile removal activities must be delayed or halted;
     Two Protected Species Observers (PSOs) will be employed 
and establish monitoring locations. The Holder must establish 
monitoring locations as described in the Monitoring Plan. For all pile 
removal activities, a minimum of one PSO must be assigned to each 
active pile removal location to monitor the shutdown zones. PSO(s) must 
be able to monitor the entire shutdown zone and the entire Level B 
harassment zone, or out to at least 400 m of the radial distance of the 
larger Level B harassment zones towards the Navigation Channel. In the 
event of concurrent pile removal (i.e., via two pile clippers) at two 
different locations that cannot be appropriately monitored by one PSO, 
the pier or location where the lead PSO is stationed being blocked by a 
refueling vessel or other obstruction, multiple PSOs may be necessary 
to monitor the necessary

[[Page 38292]]

shutdown and Level B harassment zones;
     If pile removal activities have been halted or delayed due 
to the presence of a species in the shutdown zone, activities may 
commence only after the animal has been visually sighted to have 
voluntarily exited the shutdown zone, or after 15 minutes have passed 
without a re-detection of the animal;
     If the take reaches the authorized limit for an authorized 
species, or if a marine mammal species that is not authorized for this 
proposed project enters the Level B harassment zone, pile removal will 
cease until consultation with NMFS can occur. If in-water pile removal 
activities are occurring when a non-authorized species enters the Level 
B harassment zone, activities must shutdown;
     The placement of the PSOs during all pile removal 
activities will ensure that the entire shutdown zone is visible. Should 
environmental conditions deteriorate such that marine mammals within 
the entire shutdown zone would not be visible (e.g., fog, heavy rain), 
pile removal must be delayed until the lead PSO is confident that 
marine mammals within the shutdown could be detected;
     PSOs must record all observations of marine mammals as 
described in the Monitoring Plan, regardless of distance from the pile 
being driven. PSOs shall document any behavioral reactions in concert 
with distance from piles being driven or removed;
     The marine mammal monitoring reports must contain the 
informational elements described in the Monitoring Plan;
     A draft marine mammal monitoring report, and PSO 
datasheets and/or raw sighting data, must be submitted to NMFS within 
90 calendar days after the completion of pile driving activities. If no 
comments are received from NMFS within 30 calendar days, the draft 
report will constitute the final report. If comments are received, a 
final report addressing NMFS comments must be submitted within 30 
calendar days after receipt of comments; and
     In the event that personnel involved in the construction 
activities discover an injured or dead marine mammal, the IHA-holder 
must immediately cease the specified activities and report the incident 
to the Office of Protected Resources (OPR) 
([email protected] and [email protected]), NMFS and 
to the West Coast Regional Stranding Coordinator as soon as feasible.

                                     Table 9--Shutdown and Harassment Zones
                                                    [Meters]
----------------------------------------------------------------------------------------------------------------
                                                                                    Harassment    Shutdown  zone
               Pile information                          Removal method                zone             \1\
----------------------------------------------------------------------------------------------------------------
13-inch polycarbonate pile....................  One pile clipper................             423              20
14-inch, 16-inch concrete piles...............  One pile clipper................             250
14-inch, 16-inch concrete pile................  Two pile clippers...............             250
14-inch, 16-inch concrete pile................  Underwater chainsaw.............             229
14-inch, 16-inch concrete pile................  Diamond wire saw................             575
14-inch, 16-inch concrete pile................  Vibratory hammer................             311
----------------------------------------------------------------------------------------------------------------
\1\ The shutdown zone is the same for all mid-frequency cetaceans, phocid pinnipeds, and otariid pinnipeds.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that would result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. 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 action; 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).
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring must be conducted in accordance with the 
submitted Monitoring Plan and the Proposed Mitigation, Monitoring, and 
Reporting Measures section of the IHA. Marine mammal monitoring during 
pile driving and removal must be conducted by NMFS-approved PSOs in a 
manner consistent with the following:
     Independent PSOs (i.e., not construction personnel) who 
have no other assigned tasks during monitoring periods must be used;
     At least one PSO must have prior experience performing the 
duties of a PSO during construction activity pursuant to a NMFS-issued 
incidental take authorization.
     Other PSOs may substitute education (degree in biological 
science or related field) or training for experience;
     Where a team of two or more PSOs are required, one PSO 
would be designated as the ``Command'', or lead PSO, and would 
coordinate all monitoring efforts. The lead PSO must have prior 
experience performing the duties of an observer;

[[Page 38293]]

     In the event of concurrent pile removal activities, two 
lead PSOs may be designated and would coordinate and communicate all 
monitoring efforts if a single observer cannot observe the two 
concurrent activities. Each position would act independently and both 
would maintain the ability to call for a shutdown. Each lead PSOs would 
communicate to the other of a potential sighting of a marine protected 
species traveling from one location to the other within the appropriate 
shutdown and Level B zones during concurrent pile removal activities.
     The Navy must submit PSO Curriculum Vitae (CV) for 
approval by NMFS prior to the onset of pile driving.
    PSOs must 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.
    Up to two PSOs would be employed. PSO locations would provide an 
unobstructed view of all water within the shutdown zone, and as much of 
the Level A and Level B harassment zones as possible. PSO locations 
have been discussed above. An additional monitoring location is 
described as follows:
    (1) An additional monitoring location on the Fuel Pier trestle or 
on a captained vessel may be utilized for pre-activity monitoring if 
the monitoring zone is beyond the visual range of the lead PSO's 
position. This vessel would start south of the Project area (where 
potential marine mammal occurrence is lowest) before the pile removal 
activity has begun and move north.
    Monitoring would be conducted 30 minutes before, during, and 30 
minutes after pile removal activities. In addition, observers shall 
record all incidents of marine mammal occurrence, regardless of 
distance from activity and distance from the buffered shutdown zone and 
Level B harassment isopleth, and shall document any behavioral 
reactions in concert with distance from piles being removed.

Hydroacoustic Monitoring and Reporting

    The Navy has indicated in their application that they may perform 
hydroacoustic monitoring on any removal method and sound source that 
was not previously recorded and included in the Compendium of 
Underwater and Airborne Sound Data during Pile Installation and In-
Water Demolition Activities in San Diego Bay, California (NAVFAC SW, 
2020). However, as data from the Compendium (for pile clippers, wire 
saw, and underwater chainsaw) and the City of Seattle Pier 62 project 
(for the vibratory hammer; Greenbusch Group, 2018) are recent, it is 
unlikely hydroacoustic monitoring will occur during this project.

Reporting

    A draft marine mammal monitoring and acoustic measurement report 
would be submitted to NMFS within 90 calendar days after the completion 
of these activities, or 60 days prior to a requested date or issuance 
of any future IHAs for projects at the same location, whichever comes 
first. The report would include an overall description of work 
completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including how many and what type of piles were 
removed and by what method (i.e., vibratory and if other removal 
methods were used);
     Weather parameters and water conditions during each 
monitoring period (e.g., wind speed, percent cover, visibility, sea 
state);
     The number of marine mammals observed, by species, 
relative to the pile location and if pile removal was occurring at time 
of sighting;
     Age and sex class, if possible, of all marine mammals 
observed;
     PSO locations during marine mammal monitoring;
     Distances and bearings of each marine mammal observed to 
the pile being driven or removed for each sighting (if pile removal was 
occurring at time of sighting);
     Description of any marine mammal behavior patterns during 
observation, including direction of travel and estimated time spent 
within the Level A and Level B harassment zones while the source was 
active;
     Number of individuals of each species (differentiated by 
month as appropriate) detected within the monitoring zone, and 
estimates of number of marine mammals taken, by species (a correction 
factor may be applied to total take numbers, as appropriate);
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting behavior of the animal, if 
any;
     Description of attempts to distinguish between the number 
of individual animals taken and the number of incidences of take, such 
as ability to track groups or individuals; and
     Submit all PSO datasheets and/or raw sighting data (in a 
separate file from the Final Report referenced immediately above).
    If no comments are received from NMFS within 30 days, the draft 
final report would constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, and the lead PSO determines 
that the cause of the injury or death is unknown and the death is 
relatively recent (i.e., in less than a moderate state of 
decomposition), the lead PSO would report to the Navy POC. The Navy POC 
shall then report the incident to the Office of Protected Resources 
(OPR), NMFS and to the regional stranding coordinator as soon as 
feasible. If the death or injury was clearly caused by the specified 
activity, the Navy must immediately cease the specified activities 
until NMFS is able to review the circumstances of the incident and 
determine what, if any, additional measures are appropriate to ensure 
compliance with the terms of the IHA. The IHA-holder must not resume 
their activities until notified by NMFS. The report must include the 
following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);

[[Page 38294]]

     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     Description of marine mammals observation in the 24-hours 
preceding the incident;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), 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's 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 environmental 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).
    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 removal activities have the potential to disturb or displace 
marine mammals. Specifically, the project activities may result in 
take, in the form of Level B harassment only from underwater sounds 
generated from pile cutting and removal activities. Takes could occur 
if individuals are present in the ensonified zones when these 
activities are underway. The potential for harassment is minimized 
through the construction method and the implementation of the planned 
mitigation measures (see Proposed Mitigation, Monitoring, and Reporting 
Measures section).
    Take would occur within a limited, confined area (mouth of San 
Diego Bay) 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.
    Behavioral responses of marine mammals to pile removal at the 
project site, if any, are expected to be mild and temporary. Marine 
mammals within the Level B harassment zone may not show any visual cues 
they are disturbed by activities (as noted during modification to the 
Kodiak Ferry Dock (ABR, 2016; see 80 FR 60636, October 7, 2015)) or 
could become alert, avoid the area, leave the area, or display other 
mild responses that are not observable such as changes in vocalization 
patterns. Given the short duration of noise-generating activities per 
day and that pile removal would occur across six months, any harassment 
would be temporary. There are no areas or times of known biological 
importance for any of the affected species.
    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 the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality or Level A harassment is anticipated or 
authorized;
     No biologically important areas have been identified with 
the project area;
     The Navy is required to implement mitigation measures to 
minimize impacts, such as PSO observation and a shutdown zone of 20 m 
(66 ft);
     For all species, San Diego Bay is a very small and 
peripheral part of their range; 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 would have a negligible impact 
on all affected marine mammal species or stocks.

Small Numbers

    As noted above, 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 6 species (refer back to Table 
8). For most requested species, the proposed take of individuals is 
less than 1% of the abundance of the affected stock (with exception for 
common bottlenose dolphins at 18.54%). This is likely a conservative 
estimate because it assumes all take 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, Monitoring, and Reporting Measures 
section) and the anticipated take of marine mammals, NMFS preliminarily 
finds that small numbers of marine mammals would be taken relative to 
the population size of the affected species or stocks.

[[Page 38295]]

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 (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 Navy to begin the Naval Base Point Loma Fuel Pier 
Inboard Pile Removal Project in San Diego, California on January 15, 
2022, provided the previously mentioned mitigation, monitoring, and 
reporting requirements are incorporated. Once started, the IHA would be 
valid for one year (end January 14, 2023). A draft of the proposed IHA 
can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

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 Naval 
Base Point Loma Fuel Pier Inboard Pile Removal Project. We also request 
at this time 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, one-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, 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).
    (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 would remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: July 15, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-15378 Filed 7-19-21; 8:45 am]
BILLING CODE 3510-22-P