Notice2021-15378
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Naval Base Point Loma Fuel Pier Inboard Pile Removal Project
Primary source
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Published
July 20, 2021
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
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.
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[Federal Register Volume 86, Number 136 (Tuesday, July 20, 2021)]
[Notices]
[Pages 38274-38295]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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 <a href="/cdn-cgi/l/email-protection#5d14090d730d322931323e361d33323c3c733a322b"><span class="__cf_email__" data-cfemail="561f0206780639223a39353d163839373778313920">[email protected]</span></a>.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at
<a href="http://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> without change. All personal identifying
[[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: <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>. 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 (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>).
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 (L<INF>50</INF>; 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; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
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; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>). 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
[[Page 38278]]
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>).
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
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Family Otariidae (eared seals and
sea lions):
California sea lion............. Zalophus californianus. United States.......... -, -, N 257,606 (N/A, 233,515, 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).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a> assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\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
(SEL<INF>cum</INF>) in an accelerating fashion: At low exposures with
lower SEL<INF>cum</INF>, the amount of TTS is typically small and the
growth curves have shallow slopes. At exposures with higher
SEL<INF>cum</INF>, the growth curves become steeper and approach linear
relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor
porpoise (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
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
[[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
<a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-naval-base-san-diego-pier-6-replacement-project-san-diego">https://www.fisheries.noaa.gov/action/incidental-take-authorization-naval-base-san-diego-pier-6-replacement-project-san-diego</a>), 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:
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> The marine mammal monitoring reports must contain the
informational elements described in the Monitoring Plan;
<bullet> 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
<bullet> 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)
(<a href="/cdn-cgi/l/email-protection#98c8cab6d1ccc8b6d5f7f6f1ecf7eaf1f6ffcafde8f7eaecebd8f6f7f9f9b6fff7ee"><span class="__cf_email__" data-cfemail="a2f2f08cebf6f28cefcdcccbd6cdd0cbccc5f0c7d2cdd0d6d1e2cccdc3c38cc5cdd4">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#cd84999de39da2b9a1a2aea68da3a2acace3aaa2bb"><span class="__cf_email__" data-cfemail="6b223f3b453b041f070408002b05040a0a450c041d">[email protected]</span></a>), 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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density).
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas).
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors.
<bullet> How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks.
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat).
<bullet> 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:
<bullet> Independent PSOs (i.e., not construction personnel) who
have no other assigned tasks during monitoring periods must be used;
<bullet> 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.
<bullet> Other PSOs may substitute education (degree in biological
science or related field) or training for experience;
<bullet> 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]]
<bullet> 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.
<bullet> 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:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
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:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> 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);
<bullet> Weather parameters and water conditions during each
monitoring period (e.g., wind speed, percent cover, visibility, sea
state);
<bullet> The number of marine mammals observed, by species,
relative to the pile location and if pile removal was occurring at time
of sighting;
<bullet> Age and sex class, if possible, of all marine mammals
observed;
<bullet> PSO locations during marine mammal monitoring;
<bullet> 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);
<bullet> 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;
<bullet> 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);
<bullet> 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;
<bullet> 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
<bullet> 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:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
[[Page 38294]]
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> Description of marine mammals observation in the 24-hours
preceding the incident;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any 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:
<bullet> No mortality or Level A harassment is anticipated or
authorized;
<bullet> No biologically important areas have been identified with
the project area;
<bullet> The Navy is required to implement mitigation measures to
minimize impacts, such as PSO observation and a shutdown zone of 20 m
(66 ft);
<bullet> For all species, San Diego Bay is a very small and
peripheral part of their range; and
<bullet> 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 <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>.
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:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond one year from
expiration of the initial IHA).
<bullet> The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures 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
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