Notice2022-24847
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental To Replacement of Pier 302 at Naval Base Point Loma, San Diego, California
Primary source
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Published
November 15, 2022
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the U.S. Navy for authorization to take marine mammals incidental to the replacement of Pier 302 at Naval Base Point Loma in San Diego Bay, San Diego, CA. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, one-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
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[Federal Register Volume 87, Number 219 (Tuesday, November 15, 2022)]
[Notices]
[Pages 68442-68461]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-24847]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XC335]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental To Replacement of Pier 302 at Naval
Base Point Loma, San Diego, California
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the U.S. Navy for
authorization to take marine mammals incidental to the replacement of
Pier 302 at Naval Base Point Loma in San Diego Bay, San Diego, CA.
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting
comments on its proposal to issue an incidental harassment
authorization (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time, one-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision.
DATES: Comments and information must be received no later than December
15, 2022.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
<a href="/cdn-cgi/l/email-protection#eba2bfbbc5818e989882888a9f8a92878499ab85848a8ac58c849d"><span class="__cf_email__" data-cfemail="1b524f4b35717e686872787a6f7a627774695b75747a7a357c746d">[email protected]</span></a>.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at
<a href="http://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Jessica Taylor, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. In case of problems
accessing these documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on
[[Page 68443]]
the species or stock(s) and will not have an unmitigable adverse impact
on the availability of the species or stock(s) for taking for
subsistence uses (where relevant). Further, NMFS must prescribe the
permissible methods of taking and other ``means of effecting the least
practicable adverse impact'' on the affected species or stocks and
their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance, and on the availability of
the species or stocks for taking for certain subsistence uses (referred
to in shorthand as ``mitigation''); and requirements pertaining to the
mitigation, monitoring and reporting of the takings are set forth. The
definitions of all applicable MMPA statutory terms cited above are
included in the relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has
preliminarily determined that the issuance of the proposed IHA
qualifies to be categorically excluded from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On July 27, 2022, NMFS received a request from the U.S. Navy for an
IHA to take marine mammals incidental to construction activities
associated with replacing Pier 302 at Naval Base Point Loma (NBPL), San
Diego, CA. Following NMFS' review of the application, the U.S. Navy
submitted a revised version on September 22, 2022. The application was
deemed adequate and complete on October 27, 2022. The U.S. Navy's
request is for take of six species of marine mammals by Level B
harassment only. Neither the U.S. Navy nor NMFS expect serious injury
or mortality to result from this activity, therefore, an IHA is
appropriate.
NMFS has previously issued IHAs to the U.S. Navy for similar work
over the past 9 years at NBPL in San Diego Bay (Bay), including IHAs
issued effective from September 1, 2013, through August 31, 2014 (78 FR
44539, July 24, 2013; Year 1 Project), October 8, 2014 through October
7, 2015 (79 FR 65378, November 4, 2014; Year 2 Project), October 8,
2015 through October 7, 2016 (80 FR 62032, October 15, 2015; Year 3
Project), October 8, 2016 through October 7, 2017 (81 FR 66628,
September 28, 2016; Year 4 Project), October 8, 2017 through October 7,
2018 (82 FR 45811, October 2, 2017; Year 5 Project), September 15, 2020
through September 14, 2021 (85 FR 33129, June 1, 2020; Floating Dry
Dock Project), October 1, 2021 through September 30, 2022 (86 FR 7993,
February 3, 2021; Pier 6 Replacement Project), and January 15, 2022
through January 14, 2023 (86 FR 48986, September 1, 2021; Fuel Pier
Inboard Pile Removal Project). The U.S. Navy complied with all the
requirements (e.g., mitigation, monitoring, and reporting) of the
previous IHA and information regarding their monitoring results
specific to NBPL may be found in the Estimated Take section.
Description of Proposed Activity
Overview
The U.S. Navy plans to replace Pier 302 at the Naval Information
Warfare Center (NIWC) Pacific Bayside Complex on NBPL. Pier 302 houses
the U.S. Navy marine mammal pens and support vessels. As part of the
proposed action, the U.S. Navy would use vibratory extraction to remove
the existing components of marine mammal pens, and impact and vibratory
hammers to install new pens. The purpose of the project is to provide
the U.S. Navy's marine mammal program with adequate facilities to house
its marine mammals and provide a safe working environment for personnel
to support the U.S. Navy's overall mission to maintain, train, and
equip combat ready Naval forces.
The Navy's proposed activity includes impact and vibratory pile
driving, which may result in the incidental take of marine mammals, by
harassment only. No Level A harassment is anticipated to occur, and
none is proposed for authorization. Due to mitigation measures, only
takes by Level B harassment are requested. NBPL is located along the
mouth and northern edge of San Diego Bay, CA. The proposed action
covers an area of 9,061 feet (ft.)\2\ (842 meters (m)\2\). Construction
activities would begin on October 1, 2023 and last through September
30, 2024.
Dates and Duration
In-water construction activities would occur over 32 days within a
1 year window from October 1, 2023 to September 30, 2024. The Navy
states that it will conduct work only in daylight hours. The proposed
in-water work schedule is shown in Table 1. In-water work would consist
of 18 days of pile removal, then 14 days of pile installation. Pile
removal would occur at a rate of one to five piles per day, while pile
installation would take place at a rate of one to four piles per day,
depending upon the type of pile. It is assumed that pile removal and
installation would occur on separate days. In addition to vibratory
extraction, some piles may be removed by other methods, such as dead
pull, hydraulic pile clipper, wire saw, underwater chainsaw, or high-
pressure water jet (Table 1). However, these additional methods are not
expected to result in take and are, therefore, not discussed further.
In-water pile removal and pile driving is planned from October 1, 2023
through March 31, 2024 in order to avoid construction activities during
the breeding and nesting season of the endangered California least
tern.
Table 1--Proposed In-Water Construction Activity Schedule
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Estimated duration Total
Pile type Method Number of piles Piles/day Estimated blow per pile (mm:ss) estimated
count per pile \3\ \3\ days
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Pile Removal Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
18'' octagonal concrete........... Vibratory Extraction 22................. 5 N/A................ 15:00.............. 5
\1\.
18'' round steel.................. Vibratory Extraction. 3.................. 1 N/A................ 15:00.............. 3
[[Page 68444]]
14'' round timber................. Dead pull............ up to 10........... 1 N/A................ N/A................ 10
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Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
24'' octagonal concrete........... Impact hammer \2\.... 30................. 4 500................ N/A................ 8
14'' square concrete.............. Impact Hammer........ 2.................. 1 250................ N/A................ 2
6'' round steel................... vibratory hammer..... 17................. 5 N/A................ 1:00............... 4
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\1\ While other methods of pile removal are possible, vibratory extraction is the most likely method that will be used to extract piles. No quantitative
exposure analysis was conducted for other potential pile removal methods (hydraulic pile clipper, wire saw, underwater chainsaw, high-pressure water
jet) as these methods are not expected to result in take.
\2\ With or without high-pressure water jetting occurring simultaneously.
\3\ Estimated durations and blow counts as provided by the construction contractor.
Specific Geographic Region
NBPL is located along the mouth and northern edge of San Diego Bay,
California (Figure 1). San Diego Bay is a narrow, crescent-shaped
natural embayment with an approximate length of 24 kilometers (km) and
total area of approximately 11,000 acres (44.5 km \2\) (Port of San
Diego, 2007). Depths of the bay range from 23 meters (m) below mean
lower low water (MLLW) to less than 1.2 m below MLLW at the southern
end of the bay (Merkel & Associates, Inc., 2009). The majority of the
bay is less than 15 m deep (Merkel & Associates, Inc., 2009). The bay
also includes a main navigation channel, maintained at a depth of 14.3
m below MLLW. This channel is utilized for transit by private,
commercial, and military vessels (NOAA, 2010). Water depth in the area
of Pier 302 ranges from approximately 0-6 m below MLLW.
San Diego Bay experiences mixed diurnal and semi-diurnal tides with
a tidal range of approximately 1.7 m. Water temperature in the bay
typically ranges from 15.1 to 26.1 [deg]C while salinities of the
proposed project area are similar to those of the open ocean, 32.8 to
33 parts per thousand (ppt) (Tierra Data Inc., 2012). San Diego Bay is
heavily used by commercial, recreational, and military vessels. Ship
noise in the bay has the potential to mask underwater sound produced by
the proposed project. Based upon recent measurements of underwater
sound in San Diego Bay, the median ambient underwater sound pressure
level (SPL) in areas of the bay that may experience project
construction noise averages approximately 129.6 dB re 1 [mu]Pa.
[GRAPHIC] [TIFF OMITTED] TN15NO22.001
[[Page 68445]]
Figure 1--Proposed Action Area
Detailed Description of Specific Activity
The purpose of this project is to replace the existing Pier 302 at
NBPL to provide the Navy's marine mammal program with adequate
facilities to house its marine mammals and provide a safe working
environment for personnel supporting the Navy's overall mission to
maintain, train, and equip combat ready Naval forces. Pier 302
currently house the U.S. Navy marine mammal pens and small program
support vessels. The existing Pier 302 was built in 1937 and partially
modified in 1987. Currently, the steam beams are in poor condition,
concrete piles are corroded, and timber decking is deteriorated
(Collins, 2018). The existing pier covers a slightly larger area of
1,800 ft.\2\ (1,003 m\2\) than the proposed action would cover.
The Navy proposes to remove the marine mammal pens, gangways, and
floating walkways from the area and demolish the existing pier. The
Navy would remove 22 18'' concrete structural piles, 3 18'' steel pipe
guide piles, and up to 10 14'' timber piles potentially through a
variety of extraction methods, including vibratory extraction, dead
pull, hydraulic pile clipper, wire saw, underwater chainsaw, or high-
pressure water jet (Table 1). Existing concrete and steel piles would
be removed using a vibratory extractor and pile clamp by latching on to
the pile with the clamp, vibrating the pile to break surface tension,
and applying upward pressure to extract the whole pile. The dead pull
method may also be used to remove steel or timber piles by securing the
piles above the water line and applying upwards pressure to the pile.
The timber piles are remnant piles from the original 1937 construction,
but the total number of piles and their placement in the pier footprint
are unknown. Some of these piles were cut during the 1987
modifications, but it is unknown how many of them remain nor at what
depth they were cut. In the case of removal by a hydraulic pile
clipper, the hydraulic clipper would be placed over each pile and
lowered to 1 foot (0.3 m) below the mudline, where it would be cut. The
pile below would remain in place. Diver assistance may or may not be
required during this specific pile removal activity. Underwater
chainsaws or wire saws operated by a diver may also be used to remove
piles at the mudline. Once the piles are removed or cut, a crane would
remove the pile and set it onto a barge for transport. Ultimately, the
contractor would decide on the use one of the above described methods
depending on which proves to be most efficient. Once extracted, the
piles will be loaded onto a support barge for eventual offloading. For
purposes of analysis, the Navy assumes that all steel and concrete
piles would be removed via vibratory extraction. Removal of timber
piles is assumed to occur via methods that are not anticipated to
result in take of marine mammals.
After demolition of the existing pier, the Navy would construct a
new cement pier and gangways through the installation of 30 24'' (0.6
m) structural concrete piles, 2 14'' (0.4 m) concrete guide piles, and
17 6'' (0.2 m) steel pipe guide piles. The piles would be installed
either through the use of an impact hammer, with our without water
jetting, or vibratory hammer. Floating walkways, gangways, and marine
mammal pens would be reinstalled to the north and south of the newly
constructed pier. The newly constructed Pier 302 would have a similar
footprint to the original Pier 302.
Shore side improvements would include the construction of a new
storm drain outlet and revetment under the base of the new pier. Shore
side improvement, removal and installation of floating walkways,
gangways, and marine mammal pens, and extraction methods such as dead
pull, hydraulic pile clipper, wire saw, underwater chainsaw, or high-
pressure water jet are not expected to result in take of marine mammals
and are, therefore, not discussed further.
The Navy's previous work in the portion of San Diego Bay closest to
the location of this proposed work was the Fuel Pier Replacement
project, which occurred over 5 years from 2013 to 2018. We reference
observational data obtained during monitoring required through IHAs
issued to the Navy in association with this project in the following
sections. Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, incorporated here by reference, instead of
reprinting the information. Additional information regarding population
trends and threats may be found in NMFS' Stock Assessment Reports
(SARs; <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these
species (e.g., physical and behavioral descriptions) may be found on
NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists all species or stocks for which take is expected and
proposed to be authorized for this activity, and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is expected to occur, PBR
and annual serious injury and mortality from anthropogenic sources are
included here as gross indicators of the status of the species or
stocks and other threats.
There are six marine mammal species that are potentially expected
to be present during all or a portion of the in-water work associated
with this project in San Diego Bay, including the California sea lion
(Zalophus californianus), the northern elephant seal (Mirounga
angustirostris), the harbor seal (Phoca vitulina), the bottlenose
dolphin (Tursiops truncatus), the Pacific white-sided dolphin
(Lagenorhynchus obliquidens), and the common dolphin (Delphinus
delphis). The Committee on Taxonomy (<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>)
recently determined both the long-beaked and short-beaked common
dolphin belong in the same species and we adopt this taxonomy. However,
the SARs still describe the two as separate stocks, and that stock
information is presented in Table 2. Marine mammal abundance estimates
presented in this document represent the total number of individuals
that make up a given stock or the total number estimated within a
particular study or survey area. NMFS' stock abundance estimates. For
some species, this geographic area may extend beyond U.S. waters. All
stocks managed under the MMPA in this region are assessed in NMFS' U.S.
Pacific 2021 SARs. All values presented in Table 2 are the most recent
available at the time of publication and are available online at:
www.fisheries.noaa.gov/national/
[[Page 68446]]
marine-mammal-protection/marine-mammal-stock-assessments).
Table 2--Marine Mammal Species \4\ Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Artiodactyla--Infraorder Cetacea--Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Bottlenose dolphin.............. Tursiops truncatus..... California Coastal..... -, -, N 453 (0.06, 346, 2011). 2.7 >=2.0
Short-beaked common dolphin..... Delphinus delphis California/Oregon/ -, -, N 1,056,308 (0.21, 8889 >=30.5
delphis. Washington. 888,971, 2018).
Long-beaked common dolphin...... Delphinus delphis California............. -, -, N 83,379 (0.216, 69,636, 668 >=29.7
capensis. 2018).
Pacific white-sided dolphin..... Lagenorhynchus California/Oregon/ -, -, N 34,999 (0.222, 29,090, 279 7
obliquidens. Washington. 2018).
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Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
California sea lion............. Zalophus californianus. U.S.................... -, -, N 257,606 (N/A,233,515, 14011 >320
2014).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulana......... California............. -, -, N 30,968 (N/A, 27,348, 1641 43
2012).
Northern elephant seal.......... Mirounga angustirostris California breeding.... -, -, N 187,386 (N/A, 85,369, 5122 13.7
2013).
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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 from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>; Committee on Taxonomy (2022)).
As indicated above, all six species (with seven managed stocks) in
Table 2 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. While gray whales,
Risso's dolphins, and Steller sea lions have been sighted around
California coastal waters in the past, these species' general spatial
occurrence is such that take is not expected to occur as they typically
occur more offshore, and they are not discussed further beyond the
explanation provided here.
Specifically, gray whales may be observed in San Diego Bay
sporadically during their January southbound migratory periods (Naval
Facilities Engineering Command, Southwest and Port of San Diego Bay,
2013), and have previously been included in take authorizations for
past projects and IHAs relating to NBPL (refer back to the Year 1-5
IHAs cited above). However, a recent Monitoring Report from October 8,
2017 to January 25, 2018 (NAVFAC SW, 2018b) at NBPL, indicated no
sightings occurred for gray whales. Only two gray whales were spotted
in the October 8, 2016 to April 30, 2017 (NAVFAC SW, 2017) Monitoring
Report by the Navy. During another recent pier replacement project at
Naval Base San Diego, south of the proposed project area, gray whales
also were not sighted during monitoring (NAVFAC SW, 2022).
Risso's dolphins have not been seen in San Diego Bay but are known
to be common in southern California coastal waters (Campbell et al.,
2010). While take of Risso's dolphins have been authorized in three of
the past IHAs for NBPL (see Year 3 IHA at 80 FR 62032, October 15,
2015; Year 4 IHA at 81 FR 66628, September 28, 2016; and Year 5 IHA at
82 FR 45811, October 2, 2017, for examples), no Risso's dolphins were
sighted during any of those projects.
Furthermore, other species that occur in the Southern California
Bight may have the potential for isolated occurrence within San Diego
Bay or just offshore. In particular, a short-finned pilot whale
(Globicephala macrorhynchus) was observed off Ballast Point, and a
Steller sea lion (Eumetopias jubatus monteriensis) was seen in the
project area during the Year 2 project at NBPL (79 FR 65378, November
4, 2014). However, these species are not typically observed near the
project area and, we it is unlikely that they will occur during this
proposed action. Given the unlikelihood of their exposure to the sounds
generated from the project, these species are not considered further.
Bottlenose Dolphin
The California coastal stock of bottlenose dolphin is distinct from
the offshore population (Perrin et al., 2011; Lowther-Thielking et al.,
2015) and occurs in the immediate (within 1 km of shore) coastal
waters, primarily between Point Conception, California, and San
Quintin, Mexico (Hansen, 1990; Carretta et al., 1998; Carretta et al.,
2022). California coastal bottlenose dolphins show little site fidelity
and likely move within their home range in response to patchy
concentrations of nearshore prey (Defran and Weller, 1999; Bearzi et
al., 2009). After finding concentrations of prey, animals may then
forage within a more limited spatial extent to take advantage of this
local accumulation until such time that prey abundance is reduced,
likely then shifting location once again and possibly covering larger
distances. Oceanographic events may influence the distribution and
residency patterns of dolphins (Hansen and Defran, 1990; Wells et al.,
1990). Along the California coast, bottlenose dolphin distribution and
movements may be linked to prey distribution (Defran and
[[Page 68447]]
Weller, 1999; Bearzi et al., 2009). In San Diego Bay, bottlenose
dolphins may be observed foraging on a variety of fish species,
including croaker, mackerel, grunts, and mullet (Defran et al., 1986).
In southern California, coastal bottlenose dolphins are typically
found within 250 m of the shoreline (Hansen and Defran, 1993). Coastal
bottlenose dolphins occur sporadically and in highly variable numbers
and locations in San Diego Bay. Navy surveys indicated that bottlenose
dolphins were most commonly sighted in April, and more dolphins were
observed during El Ni[ntilde]o years. Navy surveys frequently result in
no observations of bottlenose dolphins, and sightings have ranged from
0-8 groups observed (0-40 individuals). Approximately 67 individual
bottlenose dolphins were observed during the fourth year of the NBPL
Fuel Pier Replacement project over 152 days of monitoring.
Approximately 13 individual bottlenose dolphins were observed over 49
days of monitoring during Year 5 of the NBPL fuel pier replacement
project in San Diego Bay (NAVFAC SW, 2017b; 2018b).
Common Dolphin (Short-Beaked and Long-Beaked)
Short-beaked common dolphins are the most abundant cetacean off
California and are widely distributed between the coast and
approximately 300 nautical miles (nmi; 555.6 km) offshore. In contrast,
long-beaked common dolphins generally occur within 50 nmi (92.6 km)
offshore. Both stocks may shift their distributions seasonally and
annually in response to oceanographic conditions and prey availability
(Carretta et al., 2022). Long-beaked common dolphins tend to prefer
shallower, warmer waters as compared to the short-beaked common dolphin
(Perrin, 2009), yet both stocks appear to be more abundant in coastal
waters during warm-water months (Bearzi, 2005). Within San Diego Bay,
these two stocks' share overlapping distributions, although they are
likely long-beaked (as described by the stranding of this species from
San Diego Bay to the U.S.-Mexico border (Danil and St. Leger, 2011).
However, it is unlikely that observers would be able to differentiate
the specific species in the field.
Common dolphins are often found in large groups of hundreds or even
thousands. Within San Diego Bay, sightings of common dolphins are
intermittent and most likely during the late spring and early summer
when bait fish arrive in the bay. Common dolphins have primarily been
observed in the north and north central Bay in groups of 6 to less than
100 animals. The groups typically move rather quickly through the area
in tight alignment and have been occasionally observed riding the bow
wave of large ships.
Several sightings of common dolphins occurred in the bay during the
previous fuel pier demolition and construction project in 2014 and the
second period of the previous fuel pier replacement project in 2015. Of
the course of 100 days of monitoring, 850 common dolphins were observed
in San Diego Bay in 2015 (NAVFAC SW, 2015). Since it is unlikely for
the two species to be distinguished in the field, the same estimate of
individuals is used as a combined estimate for both species.
Pacific White-Sided Dolphin
Pacific white-sided dolphins are endemic to temperate waters of the
North Pacific Ocean, and are common both on the high seas and along the
continental margins (Brownell et al., 1999; Carretta et al., 2022). Off
the U.S. west coast, Pacific white-sided dolphins occur primarily in
shelf and slope waters. Sighting patterns from aerial and shipboard
surveys conducted in California, Oregon and Washington suggest seasonal
north-south movements, with animals found primarily off California
during the colder water months and shifting northward into Oregon and
Washington as water temperatures increase in late spring and summer
(Green et al., 1992; 1993; Forney and Barlow, 1998; Barlow, 2016;
Carretta et al., 2022). Pacific white[hyphen]sided dolphins are highly
social and commonly occur in groups of less than a hundred, although
groups of several thousands of individuals have been observed. They
often associate with Risso's dolphins and short[hyphen]beaked common
dolphins, and occasionally feed in association with California sea
lions and mixed species aggregations of seabirds.
Pacific white-sided dolphins are uncommon in San Diego Bay, but
observations of this species has increased during El Ni[ntilde]o years.
Given the lack of observations during the fourth year of the NBPL Fuel
Pier Replacement project, the Navy believes the monitoring data from
the second year of this project represent the most conservative numbers
of Pacific white[hyphen]sided dolphins that are likely to occur (NAVFAC
SW, 2015).
California Sea Lion
The California sea lion is the most common pinniped species in the
vicinity of NBPL and northern San Diego Bay. California sea lions
regularly occur on piers and buoys within and leading into San Diego
Bay (Merkel & Associates, Inc., 2008). In San Diego Bay, California sea
lions may also occur on rocks and bait barges.
Habitat use and distribution varies with sex and reproductive
stage. Adult males may haul out on land to breed and defend territory
from mid-May through late July. During August and September, adult
males migrate to feeding areas as far north as Puget Sound, WA and
British Columbia (Lowry et al., 1991). Females and immature California
sea lions remain near the rookeries for most of the year. Most births
occur from mid-June to mid-July. Different age classes of California
sea lions are found in the San Diego region throughout the year (Lowry
et al., 1992). Navy surveys indicate that the local population in San
Diego Bay comprises mainly adult females and sub-adult males and
females. Based upon Navy marine mammal surveys conducted throughout the
north San Diego Bay project area (Merkel & Associates, Inc., 2008;
Johnson, 2010; Lerma, 2012, 2014), many animals are typically hauled
out within the vicinity of the proposed action area. Adult males and
females are known to haul out more often during warm-water months.
The closest potential haul-out locations to Pier 302 are docks
associated with Pier 160, approximately 100 m (333 ft) to the north,
and docks at the end of Pier 99, approximately 550 m (1,804 ft) to the
south. However, these docks are in constant use for Navy operations and
training activities. California sea lions may haul-out at those
locations but are unlikely to remain for very long due to the high
levels of activity. California sea lions also haul-out at barges
associated with the Everingham Brothers Bait Barge Company that are
from 700 to 1,000 m (0.4 to 0.5 nmi) southeast of the proposed action
area. Beyond these man[hyphen]made structures, there are no known
natural haul-out locations in the vicinity of the proposed action area.
Harbor Seal
Pacific harbor seals range from Baja California to the eastern
Aleutian Islands. Harbor seals do not make extensive pelagic
migrations, but may travel hundreds of kilometers to find food or
suitable breeding areas (Herder, 1986; Harvey and Goley, 2011; Carretta
et al., 2022). Grigg et al. (2009) reported seasonal shifts in harbor
seal movements based on prey availability.
Harbor seals may haul out on rocks, buoys, or other structures and
are relatively uncommon in San Diego Bay, although harbor seals have
been observed during several past Navy
[[Page 68448]]
projects near Ballast Point (Tierra Data Inc., 2012; Jenkins, 2012),
Pier 122 (Jenkins, 2012; Bowman, 2014), along the NBPL shoreline
(Lerma, 2014) and near the Naval Mine and Anti-Submarine Warfare Comman
(NMAWC) (McConchie, 2014). During the fourth year of the NBPL fuel pier
replacement project, 88 individual harbor seals were observed over a
152 day monitoring period (NAVFAC SW, 2017; 2018a).
Elephant Seal
Northern elephant seals breed and give birth in California and Baja
California, mainly on offshore islands during the months of December to
March (Stewart and Huber, 1993; Stewart et al., 1994; Carretta et al.,
2022). Molting season takes place from March to August. In between the
spring/summer molting season and winter breeding season, northern
elephant seals migrate to feeding grounds (Carretta et al., 2022).
Males and females exhibit spatial segregation in foraging areas with
males feeding on benthic prey along the continental shelf near the Gulf
of Alaska and western Aleutian Islands, and females feeding on pelagic
prey in pelagic areas near the Gulf of Alaska and central North Pacific
(Le Boeuf et al., 2000).
Northern elephant seal populations in the U.S. and Mexico have
recovered after being reduced to near extinction by hunting (Stewart et
al., 1994) and undergoing a severe population bottleneck and loss of
genetic diversity that resulted in the population being reduced to only
an estimated 10-30 individuals (Hoelzel et al., 2002; Carretta et al.,
2022). The northern elephant seal population is estimated to have grown
at 3.8 percent annually since 1988 (Lowry et al., 2014). There are two
distinct populations of northern elephant seals, including a breeding
population in Baja California, Mexico and a breeding population on U.S.
islands off California. Northern elephant seals in the San Diego region
could be from either population (Carretta et al., 2021).
Northern elephant seals occur in the southern California bight, and
have the potential to occur in San Diego Bay (NAVFAC SW and POSD,
2013). The most recent documented occurrences of northern elephant
seals near the proposed project area was in 2015. A single distressed
juvenile was observed hauled out on the beach to the west of Pier 99
and approximately 0.6 km south of the proposed project area during the
second year of work on the Fuel Pier Replacement project at NBPL
(NAVFAC SW, 2015). In addition, a second juvenile was observed near the
NBPL Harbor Drive Annex, approximately 3 km north of the proposed
project area (McConchie, personal communication). Given the continuing,
long-term increase in the population of northern elephant seals (Lowry
et al., 2014), there is an increasing possibility of occurrence in the
project area.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al., 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may affect marine mammals and their habitat.
The Estimated Take section later in this document includes a
quantitative analysis of the number of individuals that are expected to
be taken by this activity. The Negligible Impact Analysis and
Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and whether those
impacts are reasonably expected to, or reasonably likely to, adversely
affect the species or stock through
[[Page 68449]]
effects on annual rates of recruitment or survival.
Acoustic effects on marine mammals during the specified activities
can occur from impact pile driving and vibratory driving and removal.
The effects of underwater noise from the Navy's proposed activities
have the potential to result in Level A or Level B harassment of marine
mammals in the action area.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (ANSI, 1995). The sound level of an area is
defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., waves, wind,
precipitation, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20
decibels (dB) from day to day (Richardson et al., 1995). The result is
that, depending on the source type and its intensity, sound from the
specified activities may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
In-water construction activities associated with the project would
include impact and vibratory pile driving and removal. The sounds
produced by these activities fall into one of two general sound types:
impulsive and non-impulsive. Impulsive sounds (e.g., explosions, sonic
booms, impact pile driving) are typically transient, brief (less than 1
second), broadband, and consist of high peak sound pressure with rapid
rise time and rapid decay (ANSI, 1986; NIOSH, 1998; NMFS, 2018). Non-
impulsive sounds (e.g., machinery operations such as drilling or
dredging, vibratory pile driving, underwater chainsaws, and active
sonar systems) can be broadband, narrowband or tonal, brief or
prolonged (continuous or intermittent), and typically do not have the
high peak sound pressure with raid rise/decay time that impulsive
sounds do (ANSI, 1995; NIOSH, 1998; NMFS, 2018). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997).
Two types of hammers would be used on this project, impact and
vibratory. Impact hammers operate by repeatedly dropping and/or pushing
a heavy piston onto a pile to drive the pile into the substrate. Sound
generated by impact hammers is considered impulsive. Vibratory hammers
install piles by vibrating them and allowing the weight of the hammer
to push them into the sediment. Vibratory hammers produce non-
impulsive, continuous sounds. Vibratory hammering generally produces
SPLs 10 to 20 dB lower than impact pile driving of the same-sized pile
(Oestman et al., 2009). Rise time is slower, reducing the probability
and severity of injury, and sound energy is distributed over a greater
amount of time (Nedwell and Edwards, 2002; Carlson et al., 2005).
The likely or possible impacts of the Navy's proposed activities on
marine mammals could be generated from both non-acoustic and acoustic
stressors. Potential non-acoustic stressors include the physical
presence of the equipment, vessels, and personnel; however, we expect
that any animals that approach the project site(s) close enough to be
harassed due to the presence of equipment or personnel would be within
the Level B harassment zones from pile driving and would already be
subject to harassment from the in-water activities. Therefore, any
impacts to marine mammals are expected to primarily be acoustic in
nature. Acoustic stressors are generated by heavy equipment operation
during pile installation and removal (i.e., impact and vibratory pile
driving and removal).
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving equipment is the primary means by which
marine mammals may be harassed from the Navy's specified activities. In
general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007). Generally, exposure to
pile driving and removal and other construction noise has the potential
to result in auditory threshold shifts and behavioral reactions (e.g.,
avoidance, temporary cessation of foraging and vocalizing, changes in
dive behavior). Exposure to anthropogenic noise can also lead to non-
observable physiological responses, such as an increase in stress
hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions, such
as communication and predator and prey detection. The effects of pile
driving and demolition noise on marine mammals are dependent on several
factors, including, but not limited to, sound type (e.g., impulsive vs.
non-impulsive), the species, age and sex class (e.g., adult male vs.
mother with calf), duration of exposure, the distance between the pile
and the animal, received levels, behavior at time of exposure, and
previous history with exposure (Wartzok et al., 2004; Southall et al.,
2007). Here we discuss physical auditory effects (threshold shifts)
followed by behavioral effects and potential impacts on habitat. No
physiological effects other than permanent threshold shift (PTS) are
anticipated or proposed to be authorized, and therefore are not
discussed further.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (2018), there are numerous factors
to consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how animal uses sound within the
frequency band of the signal; e.g., Kastelein et al., 2014), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
[[Page 68450]]
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40 dB
threshold shift approximates PTS onset (see Ward et al., 1958, 1959;
Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996;
Henderson et al., 2008). PTS levels for marine mammals are estimates,
because there are limited empirical data measuring PTS in marine
mammals (e.g., Kastak et al., 2008), largely due to the fact that, for
various ethical reasons, experiments involving anthropogenic noise
exposure at levels inducing PTS are not typically pursued or authorized
(NMFS, 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2018). Based on data from cetacean TTS
measurements (see Southall et al., 2007), a TTS of 6 dB is considered
the minimum threshold shift clearly larger than any day-to-day or
session-to-session variation in a subject's normal hearing ability
(Schlundt et al., 2000; Finneran et al., 2000, 2002). As described in
Finneran (2016), marine mammal studies have shown the amount of TTS
increases with cumulative sound exposure level (SEL<INF>cum</INF>) in
an accelerating fashion: At low exposures with lower SEL<INF>cum,</INF>
the amount of TTS is typically small and the growth curves have shallow
slopes. At exposures with higher SEL<INF>cum</INF>, the growth curves
become steeper and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis),
and five species of pinnipeds exposed to a limited number of sound
sources (i.e., mostly tones and octave-band noise) in laboratory
settings (Finneran, 2015). TTS was not observed in trained spotted
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive
noise at levels matching previous predictions of TTS onset (Reichmuth
et al., 2016). In general, harbor seals and harbor porpoises have a
lower TTS onset than other measured pinniped or cetacean species
(Finneran, 2015). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a, 2019b, 2020a, 2020b). In addition, TTS
can accumulate across multiple exposures, but the resulting TTS will be
less than the TTS from a single, continuous exposure with the same SEL
(Finneran et al., 2010; Kastelein et al., 2014; Kastelein et al.,
2015a; Mooney et al., 2009). This means that TTS predictions based on
the total, cumulative SEL will overestimate the amount of TTS from
intermittent exposures such as sonars and impulsive sources.
The potential for TTS from impact pile driving exists. After
exposure to playbacks of impact pile driving sounds (rate 2,760
strikes/hour) in captivity, mean TTS increased from 0 dB after 15
minute exposure to 5 dB after 360 minute exposure; recovery occurred
within 60 minutes (Kastelein et al., 2016). Additionally, the existing
marine mammal TTS data come from a limited number of individuals within
these species. No data are available on noise-induced hearing loss for
mysticetes. Nonetheless, what we considered is the best available
science. For summaries of data on TTS in marine mammals or for further
discussion of TTS onset thresholds, please see Southall et al. (2007,
2019), Finneran and Jenkins (2012), Finneran (2015), and Table 5 in
NMFS (2018).
Installing piles for this project requires impact pile driving.
There would likely be pauses in activities producing the sound during
each day. Given these pauses and the fact that many marine mammals are
likely moving through the project areas and not remaining for extended
periods of time, the potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
removal also has the potential to behaviorally disturb marine mammals.
Available studies show wide variation in response to underwater sound;
therefore, it is difficult to predict specifically how any given sound
in a particular instance might affect marine mammals perceiving the
signal. If a marine mammal does react briefly to an underwater sound by
changing its behavior or moving a small distance, the impacts of the
change are unlikely to be significant to the individual, let alone the
stock or population. However, if a sound source displaces marine
mammals from an important feeding or breeding area for a prolonged
period, impacts on individuals and populations could be significant
(e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 2005).
Disturbance may result in changing durations of surfacing and
dives, number of blows per surfacing, or moving direction and/or speed;
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior (such as tail/fluke slapping or jaw
clapping); or avoidance of areas where sound sources are located.
Pinnipeds may increase their haul-out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound
are highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al.,
2007; Weilgart, 2007; Archer et al., 2010; Southall et al., 2021).
Behavioral reactions can vary not only among individuals but also
within an individual, depending on previous experience with a sound
source, context, and numerous other factors (Ellison et al., 2012), and
can vary depending on characteristics associated with the sound source
(e.g., whether it is moving or stationary, number of sources, distance
from the source). In general, pinnipeds seem more tolerant of, or at
least habituate more quickly to, potentially disturbing underwater
sound than do cetaceans, and generally seem to be less responsive to
exposure to industrial sound than most cetaceans.
[[Page 68451]]
Please see Appendices B and C of Southall et al. (2007) as well as
Nowacek et al. (2007); Ellison et al. (2012), and Gomez et al. (2016)
for a review of studies involving marine mammal behavioral responses to
sound.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 2007;
Melc[oacute]n et al., 2012). In addition, behavioral state of the
animal plays a role in the type and severity of a behavioral response,
such as disruption to foraging (e.g., Sivle et al., 2016; Wensveen et
al., 2017). A determination of whether foraging disruptions incur
fitness consequences would require information on or estimates of the
energetic requirements of the affected individuals and the relationship
between prey availability, foraging effort and success, and the life
history stage of the animal (Goldbogen et al., 2013).
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker 2000; Romano
et al., 2002b) and, more rarely, studied in wild populations (e.g.,
Romano et al., 2002a). For example, Rolland et al. (2012) found that
noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003), however
distress is an unlikely result of these projects based on observations
of marine mammals during previous, similar projects in the area.
Masking--Sound can disrupt behavior through masking, or interfering
with, an animal's ability to detect, recognize, or discriminate between
acoustic signals of interest (e.g., those used for intraspecific
communication and social interactions, prey detection, predator
avoidance, navigation) (Richardson et al., 1995). Masking occurs when
the receipt of a sound is interfered with by another coincident sound
at similar frequencies and at similar or higher intensity, and may
occur whether the sound is natural (e.g., snapping shrimp, wind, waves,
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar,
seismic exploration) in origin. The ability of a noise source to mask
biologically important sounds depends on the characteristics of both
the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions. Masking of natural sounds can result when human activities
produce high levels of background sound at frequencies important to
marine mammals. Conversely, if the background level of underwater sound
is high (e.g., on a day with strong wind and high waves), an
anthropogenic sound source would not be detectable as far away as would
be possible under quieter conditions and would itself be masked. The
masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt
et al., 2009). San Diego Bay is heavily used by commercial,
recreational, and military vessels, and background sound levels in the
area are already elevated. Due to the transient nature of marine
mammals to move and avoid disturbance, masking is not likely to have
long-term impacts on marine mammal species within the proposed project
area.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and removal that have the potential to cause behavioral harassment,
depending on their distance from pile driving activities. Cetaceans are
not expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the acoustic criteria. We recognize that
pinnipeds in the water could be exposed to airborne sound that may
result in behavioral harassment when looking with their heads above
water. Most likely, airborne sound would cause behavioral responses
similar to those discussed above in relation to underwater sound. For
[[Page 68452]]
instance, anthropogenic sound could cause hauled-out pinnipeds to
exhibit changes in their normal behavior, such as reduction in
vocalizations, or cause them to temporarily abandon the area and move
further from the source. However, these animals would likely previously
have been ``taken'' because of exposure to underwater sound above the
behavioral harassment thresholds, which are generally larger than those
associated with airborne sound. Thus, the behavioral harassment of
these animals is already accounted for in these estimates of potential
take. Therefore, we do not believe that authorization of incidental
take resulting from airborne sound for pinnipeds is warranted, and
airborne sound is not discussed further here.
Marine Mammal Habitat Effects
The Navy's proposed construction activities could have localized,
temporary impacts on marine mammal habitat, including prey, by
increasing in-water sound pressure levels and slightly decreasing water
quality. Increased noise levels may affect acoustic habitat (see
masking discussion above) and adversely affect marine mammal prey in
the vicinity of the project areas (see discussion below). During impact
and vibratory pile driving or removal, elevated levels of underwater
noise would ensonify the project area where both fishes and mammals
occur, and could affect foraging success. Additionally, marine mammals
may avoid the area during construction, however, displacement due to
noise is expected to be temporary and is not expected to result in
long-term effects to the individuals or populations. Construction
activities are expected to be of short duration and would likely have
temporary impacts on marine mammal habitat through increases in
underwater and airborne sound.
A temporary and localized increase in turbidity near the seafloor
would occur in the immediate area surrounding the area where piles are
installed or removed. In general, turbidity associated with pile
installation is localized to about a 25-ft (7.6-m) radius around the
pile (Everitt et al., 1980). Turbidity monitoring during high-pressure
water jetting to remove caissons for the fourth IHA of the Fuel Pier
Replacement Project revealed relatively minor, if any, changes, with
only localized decreases in water clarity that dissipated within 3 to 5
minutes (but up to 10) from the start of jetting (NAVFAC SW, 2018a).
Cetaceans are not expected to be close enough to the pile driving areas
to experience effects of turbidity, and any pinnipeds could avoid
localized areas of turbidity. Local currents are anticipated to
disburse any additional suspended sediments produced by project
activities at moderate to rapid rates depending on tidal stage.
Therefore, we expect the impact from increased turbidity levels to be
discountable to marine mammals and do not discuss it further.
In-Water Construction Effects on Potential Foraging Habitat--The
area likely impacted by the Pier 302 Replacement Project is relatively
small compared to the total available habitat in San Diego Bay. The
proposed project area is highly influenced by anthropogenic activities,
and provides limited foraging habitat for marine mammals. Furthermore,
pile driving and removal at the proposed project site would not
obstruct long-term movements or migration of marine mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. The
duration of fish and marine mammal avoidance of this area after pile
driving stops is unknown, but a rapid return to normal recruitment,
distribution, and behavior is anticipated. Any behavioral avoidance by
prey of the disturbed area would still leave significantly large areas
of potential foraging habitat in the nearby vicinity.
In-water Construction Effects on Potential Prey--Sound may affect
marine mammals through impacts on the abundance, behavior, or
distribution of prey species (e.g., crustaceans, cephalopods, fish,
zooplankton, other marine mammals). Marine mammal prey varies by
species, season, and location. Here, we describe studies regarding the
effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay,
2009). Depending on their hearing anatomy and peripheral sensory
structures, which vary among species, fishes hear sounds using pressure
and particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish; several are based on
studies in support of large, multiyear bridge construction projects
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Many
studies have demonstrated that impulse sounds might affect the
distribution and behavior of some fishes, potentially impacting
foraging opportunities or increasing energetic costs (e.g., Fewtrell
and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992;
Santulli et al., 1999; Paxton et al., 2017). In response to pile
driving, Pacific sardines and northern anchovies may exhibit an
immediate startle response to individual strikes, but return to
``normal'' pre[hyphen]strike behavior following the conclusion of pile
driving with no evidence of injury as a result (Appendix C in NAVFAC
SW, 2014). However, some studies have shown no or slight reaction to
impulse sounds (e.g., Pena et al., 2013; Wardle et al., 2001; Jorgenson
and Gyselman, 2009; Popper et al., 2005).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fishes from pile driving and removal and
construction activities at the project area would be temporary
behavioral avoidance of the area. The duration of
[[Page 68453]]
fish avoidance of this area after pile driving stops is unknown, but a
rapid return to normal recruitment, distribution, and behavior is
anticipated. In general, impacts to marine mammal prey species are
expected to be minor and temporary. Further, it is anticipated that
preparation activities for pile driving or removal (i.e., positioning
of the hammer, clipper or wire saw) and upon initial startup of devices
would cause fish to move away from the affected area outside areas
where injuries may occur. Therefore, relatively small portions of the
proposed project area would be affected for short periods of time, and
the potential for effects on fish to occur would be temporary and
limited to the duration of sound[hyphen]generating activities.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed actions
are not likely to have a permanent, adverse effect on any fish habitat,
or populations of fish species. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large potential areas
fish and marine mammal foraging habitat in the nearby vicinity. Thus,
we conclude that impacts of the specified activities are not likely to
have more than short-term adverse effects on any prey habitat or
populations of prey species. Further, any impacts to marine mammal
habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to adverse
impacts on their populations.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of disruption of behavioral patterns for individual marine mammals
resulting from exposure to the acoustic sources. Based on the nature of
the activity and the anticipated effectiveness of the mitigation
measures (i.e., vibratory or impact pile driving and removal) discussed
in detail below in the Proposed Mitigation section. Level A harassment
is neither anticipated nor proposed to be authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
The Navy's proposed construction activities include the use of
continuous (vibratory pile-driving) and impulsive (impact pile-driving)
sources, and therefore the RMS SPL threshold of 160 dB re 1 [mu]Pa is
applicable for impulsive noise. For continuous noise, the RMS SPL
threshold of 129.6 dB re 1 [mu]Pa is applicable as a de facto
harassment threshold, based upon measured noise data for San Diego Bay
as referenced in the Description of Proposed Activity section.
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise from
two different types of sources (impulsive or non-impulsive). The Navy's
proposed activity includes the use of impulsive (impact hammer) and
non-impulsive (vibratory hammer) sources.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
www.fisheries.noaa.gov/national/
[[Page 68454]]
marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: L0-pk,flat: 219 Cell 2: LE, LF,24h: 199 dB.
dB; LE, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: L0-pk,flat: 230 Cell 4: LE, MF,24h: 198 dB.
dB; LE, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: L0-pk,flat: 202 Cell 6: LE, HF,24h: 173 dB.
dB; LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: L0-pk,flat: 218 Cell 8: LE, PW,24h: 201 dB.
dB; LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: L0-pk,flat: 232 Cell 10: LE,OW,24h: 219 dB.
dB; LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS
onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds
associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
exposure level (LE,) has a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to be
more reflective of International Organization for Standardization standards (ISO, 2017). The subscript
``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within the
generalized hearing range of marine mammals (i.e., 7 Hz to 160 kHz). The subscript associated with cumulative
sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF,
and HF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The
weighted cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e., varying
exposure levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate
the conditions under which these thresholds will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected by sound generated by the
primary components of the project (i.e., impact and vibratory pile
driving).
In order to calculate distances to the Level A harassment and Level
B harassment thresholds for the methods and piles being used in this
project, the Navy used acoustic monitoring data from various similar
locations to develop source levels for the different pile types, sizes,
and methods proposed for use (Table 5).
Table 5--Source Levels for Proposed Removal and Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Peak sound
pressure (dB Mean maximum SEL (dB re
Method Pile size/type re 1[mu]Pa) RMS SPL (dB re 1[mu]Pa2 sec) Source
\1\ 1 [mu]Pa) \1\ \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Extraction................... 18'' Octagonal Concrete .............. \3\ 162 .............. NAVFAC SW, 2022.
\2\.
18'' Steel Pipe........... .............. \4\ 156 .............. Denes et al., 2016.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Pile Driving.................... 24'' Octagonal Concrete... 188 176 166 Caltrans, 2020.
14'' Square Concrete...... 183 166 154 Caltrans, 2020.
Vibratory Hammer....................... 6'' Round Steel \5\....... 171 155 155 Illingworth and Rodkin, 2007.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ As measured, or calculated, at 10 m (33 ft).
\2\ In the absence of information on vibratory extraction of 18-inch octagonal concrete piles, source data from 20-inch concrete square piles NAVFAC SW
(2022) was used as a proxy source level.
\3\ The maximum mean calculated source value for 20-inch square concrete piles (NAVFAC SW, 2022) was 162 dB RMS based on unpublished data from the Pier
6 Replacement Project.
\4\ Table 20 in Denes et al. (2016) records a value of 152.4 dB RMS at 17 m (56 ft) for vibratory extraction. This data point, and a transmission loss
of 15LogR, was used to back-calculate a value of 155.9 dB RMS at 10 m (33 ft) (rounded to 156 dB RMS).
\5\ In the absence of information on vibratory installation of 6-inch round steel piles, source data from 12-inch round steel piles (Illingworth &
Rodkin, 2017) was used as a proxy source level. Abbreviations: [mu]Pa = microPascal; dB = decibel; RMS = root mean square; SPL = sound pressure level;
m = meters.
Level B Harassment Zones
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B * Log10 (R1/R2), where
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement
The recommended TL coefficient for most nearshore environments is
the practical spreading value of 15. This value results in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions, which is the most appropriate
assumption for the Navy' proposed activities. The Level B harassment
zones and areas of zones of
[[Page 68455]]
influence (ZOIs) for the Navy's proposed activities are shown in Table
6.
Table 6--Distance to Level B Harassment Thresholds and ZOI Areas
----------------------------------------------------------------------------------------------------------------
Projected radial distance to
Maximum RMS Level B harassment thresholds
Method Pile size/type SPL (dB re 1 and ensonified area \1\ \2\
[mu]Pa) \1\ -------------------------------
Distance m Area km\2\
----------------------------------------------------------------------------------------------------------------
Pile Removal Activities
----------------------------------------------------------------------------------------------------------------
18'' Octagonal Concrete. 162 1,445 3.13
Vibratory Extraction.................. 18'' Steel Pipe......... 156 575 0.68
----------------------------------------------------------------------------------------------------------------
Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving \3\............... 24'' Octagonal Concrete. 176 117 0.041
Impact Pile Driving................... 14'' Square Concrete.... 166 25 <0.01
Vibratory Hammer...................... 6'' Round Steel......... 155 494 0.45
----------------------------------------------------------------------------------------------------------------
\1\ The Level B ZOIs for continuous pile removal and installation activities are based on the distance for noise
to decay to ambient levels (129.6 dB re 1[mu]Pa), while 160 dB was used for impulsive sound.
\2\ Assumes Practical Spreading Loss.
\3\ With or without High-pressure Water Jetting.
Abbreviations: dB re 1 [mu]Pa = decibels referenced to a pressure of 1 microPascal, km\2\ = square kilometers, m
= meters, ft = feet, RMS = root mean square, ZOI = Zone of Influence.
Level A Harassment Zones
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the Technical Guidance that can be used
to relatively simply predict an isopleth distance for use in
conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources, such as pile installation or removal, the optional
User Spreadsheet tool predicts the distance at which, if a marine
mammal remained at that distance for the duration of the activity, it
would be expected to incur PTS. The isopleths generated by the User
Spreadsheet used the same TL coefficient as the Level B harassment zone
calculations (i.e., the practical spreading value of 15). Inputs used
in the User Spreadsheet (e.g., number of piles per day, duration and/or
strikes per pile) are presented in Table 1. The maximum RMS SPL/SEL SPL
and resulting isopleths are reported below in Table 7. The maximum RMS
SPL value was used to calculate Level A harassment isopleths for
vibratory pile driving and extraction activities, while the single
strike SEL SPL value was used to calculate Level A isopleths for impact
pile driving activities.
Table 7--Distances to Level A Harassment Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Single strike Project distances to Level A thresholds (m)
Maximum RMS SEL (dB re 1 Duration (hrs/-----------------------------------------------
Method Pile size/type SPL (dB re 1 [mu]Pa\2\ sec) day)
[mu]Pa) \1\ \1\ MF PW OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Removal Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Extraction.............. 18'' Octagonal 162 N/A 1.25 0.8 5.6 0.4
Concrete \2\.
18'' Steel Pipe..... \2\ 156 N/A 0.25 0.1 0.8 0.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Pile Driving............... 24'' Octagonal 176 166 1.33 4.1 \3\ 62.4 4.5
Concrete.
14'' Square Concrete 166 154 0.25 0.2 2.5 0.2
Vibratory Hammer.................. 6'' Round Steel..... 155 155 0.07 0.0 0.3 0.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ As measured at 10 m (33 ft.).
\2\ Table 20 in Denes et al. (2016) records a value of 152.4 dB RMS at 17 m (56 ft.) for vibratory extraction. This data point, and a transmission loss
of 15LogR, was used to back-calculate a value of 156 dB RMS at 10 m (33 ft.).
\3\ Value is greater than the standard shutdown zone of 20 m (see Proposed Mitigation) and will be monitored as shutdown zone to ensure no Level A takes
of harbor seals or northern elephant seals occur during impact pile driving of 24-inch octagonal concrete piles.
Abbreviations: RMS = root mean square, dB re 1 [mu]Pa = decibels referenced to a pressure of 1 microPascal, m = meters, ft = feet, MF = mid-frequency
cetaceans, PW = phocid pinnipeds, OW = otariid pinnipeds.
Marine Mammal Occurrence
In this section, we provide information about the occurrence of
marine mammals, including density or other relevant information that
will inform the take calculations. Unless otherwise specified, the term
``pile driving'' in this section, and all following sections, may refer
to either pile installation or removal. NMFS has carefully reviewed the
Navy's analysis and concludes that it represents an appropriate and
accurate method for
[[Page 68456]]
estimating incidental take that may be caused by the Navy's activities.
Daily occurrence estimates of marine mammals in the proposed
project area are based upon the Year 4 IHA monitoring report from the
Fuel Pier Replacement Project (NAVFAC SW, 2017b). Year 4 is expected to
be most representative of typical species occurrences as this
monitoring period had the highest number of activity days and the
highest average number of animals observed per day for the three most
common species in the area (California sea lion, harbor seal,
bottlenose dolphin), with the exception of Year 2. However, Year 2 was
an El Ni[ntilde]o year and not considered representative of typical
species occurrences. The Year 2 monitoring report data was used for any
species not observed in Year 4 (common dolphin, Pacific white-sided
dolphin, northern elephant seal) (NAVFAC SW, 2015) (Table 8). Years 1,
3, and 5 included significantly less monitoring effort than Years 2 and
4, and may also not be representative of typical species richness and
occurrences.
Table 8--Total and Daily Species Occurrences During Years 2 and 4 IHA Monitoring
----------------------------------------------------------------------------------------------------------------
Year 2 IHA (100 monitoring Year 4 IHA (152 monitoring
days; El Nino year) days)
Species ---------------------------------------------------------------
Average per Average per
Total observed day Total observed day
----------------------------------------------------------------------------------------------------------------
California sea lion............................. 7,507 75.1 2,263 * 14.9
Harbor seal..................................... 248 2.5 88 * 0.6
Bottlenose dolphin.............................. 695 7 67 * 0.4
Common dolphin.................................. 850 * 8.5 N/a N/a
Pacific white-sided dolphin..................... 27 * 0.3 N/a N/a
Northern elephant seal.......................... \1\ 1 \1\ 1 N/a N/a
----------------------------------------------------------------------------------------------------------------
* Mean estimate used for daily occurrences for current analysis.
\1\ Same individual hauled out each day.
Year 4 monitoring consisted of the longest effort of all 5 IHA
years for the Navy Fuel Pier Replacement Project, and daily occurrence
estimates for California sea lions, harbor seals, and bottlenose
dolphins were selected from this year. Common dolphins, Pacific white-
sided dolphins, and northern elephant seals were not sighted in Year 4;
however, these species were sighted in Year 2 monitoring. Pacific
white-sided dolphins were only sighted during this year. Daily
occurrence estimates for common dolphins and Pacific white-sided
dolphins were selected from Year 2. Only one northern elephant seal was
sighted during the Year 2 monitoring, and the same individual was
hauled out each day. Using a daily occurrence estimate from past
monitoring was, therefore, not an accurate approach for estimating
occurrence of northern elephant seals. Past monitoring efforts,
including the one northern elephant seal sighted during Year 2
monitoring and a sighting north of the project area, (McConchie, 2015;
NAVFAC SW, 2015) documented a total of two juvenile northern elephant
seals in the proposed project area, as described earlier in the
Description of Marine Mammals in Areas of Specified Activities section.
Due to increasing stock numbers, there is a reasonable probability that
this species could be sighted in the proposed project area during
construction activities. Instead of using past monitoring data to
estimate daily occurrence, it is expected that two northern elephant
seals may be observed in the proposed project area during construction
activities, based upon previous sighting data. The Navy added a buffer
of five seals to this estimate for a total of seven expected elephant
seals in the area during construction activities, and NMFS agrees with
this approach.
Monitoring during Year 4 yielded an observation of 2,263 California
sea lions over the course of the 152-day monitoring period. These
observations equate to an average of 14.9 California sea lions observed
per day, and approximately 15 California sea lions expected to be in
the vicinity of Pier 302, when this estimate is rounded.
Based upon monitoring during Year 4, 88 harbor seals were observed
over the course of the 152-day monitoring period. These observations
equate to an average of 0.6 harbor seals observed per day, and
approximately 1 seal per day expected to be in the vicinity of Pier 302
when this estimate is rounded.
Monitoring during Year 4 yielded an observation of 67 bottlenose
dolphins in the proposed project area over the course of the 152-day
monitoring period. This observation equates to an average of 0.4, or 1
if rounded, bottlenose dolphins expected to be in the vicinity of Pier
302 each day of the proposed construction activities.
During Year 2 monitoring, 850 common dolphins were sighted in the
proposed project area over the course of the 152-day monitoring period.
This equates to an average of 8.5 common dolphins observed per day.
When rounded to the nearest whole number, 9.0 individuals are expected
to be sighted per day in the vicinity of Pier 302.
Monitoring during Year 2 documented seven sightings of Pacific
white-sided dolphins, comprising 27 individuals, with an average of
0.28 individuals sighted per day of monitoring. Rounding this estimate
to the nearest whole number leads to 1.0 individual per day to be
expected to be in the vicinity of Pier 302 during the proposed
construction activities.
Take Estimation
Here we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization.
Daily occurrence estimates were multiplied by the number of days of
pile removal and installation (32 days) to calculate estimated take by
Level B harassment of California sea lions, harbor seals, bottlenose
dolphins, common dolphins, Pacific white-sided dolphins, and northern
elephant seals (Table 9).
[[Page 68457]]
Table 9--Proposed Takes by Level B Harassment and Percent of Stock Proposed To Be Authorized for Take
----------------------------------------------------------------------------------------------------------------
Percentage of
Expected daily Proposed take by population
Species average Level B proposed to be
individuals harassment authorized for
take
----------------------------------------------------------------------------------------------------------------
California sea lion \1\................................ 15 480 0.19
Harbor seal \1\........................................ 1 32 0.10
Bottlenose dolphin \1\................................. 1 32 7.1
Common dolphin (long and short beaked) \2\............. 9 288 * 0.35
Pacific white-sided dolphin \2\........................ 1 32 0.09
Northern elephant seal................................. (\3\) 7 0.004
----------------------------------------------------------------------------------------------------------------
\1\ Average daily counts based on observations during Year 4 Fuel Pier Replacement Project Monitoring (NAVFAC
SW, 2017b).
\2\ Average daily counts based on observations during Year 2 Fuel Pier Replacement Project Monitoring (NAVFAC
SW, 2015).
\3\ Expected potential of two northern elephant seals over the duration of project activity with a +5 buffer for
Level B Take.
* Percent population calculated for each stock of common dolphins. Percentage in the table represents the
percent of take of long-beaked common dolphins as this would be a greater percentage than if all take were
attributed to short-beaked common dolphins (0.03 percent).
By using the sighting-based approach, take values are not affected
by the estimated harassment distances from Tables 6 and 7. Given the
very small Level A harassment isopleths for all species and proposed
mitigation measures, no take by Level A harassment is anticipated or
proposed for this authorization.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
Shutdown Zones
Before the commencement of in-water construction activities, the
Navy would establish shutdown zones for all activities. The purpose of
a shutdown zone is to define an area within which shutdown of the
activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area. During all in-
water construction activities, the Navy has proposed to implement a
standard 20 m (66 ft) shutdown zone, with the exception of a 70 m (230
ft) zone for phocids during the use of impact pile driving for the 24''
octagonal concrete piles. These distances exceed the estimated Level A
harassment distances (Table 10). During the impact installation of the
24-inch octagonal concrete piles, the shutdown zone for phocids will be
buffered to 70 m (230 ft) to encompass the Level A harassment zone.
Adherence to this expanded shutdown zone will avoid the potential for
the take of phocids by Level A harassment during impact pile driving.
If a marine mammal enters a buffered shutdown zone, in-water activities
would be stopped until visual confirmation that the animal has left the
zone or the animal is not sighted for 15 minutes.
All marine mammals will be monitored in the Level B harassment
zones and throughout the area as far as visual monitoring can take
place. If a marine mammal enters the Level B harassment zone, in-water
activities will continue and the animal's presence within the estimated
harassment zone will be documented.
The Navy would also establish shutdown zones for all marine mammals
for which take has not been authorized or for which incidental take has
been authorized but the authorized number of takes has been met. These
zones are equivalent to the Level B harassment zones for each activity.
If a marine mammal species not covered under this IHA enters the
shutdown zone, all in-water activities will cease until the animal
leaves the zone or has not been observed for at least 1 hour, and NMFS
will be notified about species and precautions taken. Pile removal will
proceed if the non-IHA species is observed to leave the Level B
harassment zone or if 1 hour has passed since the last observation.
If shutdown and/or clearance procedures would result in an imminent
safety concern, as determined by the Navy, the in-water activity will
be allowed to continue until the safety concern has been addressed, and
the animal will be continuously monitored. The Navy Point of Contact
(POC) will be consulted before re-commencing activities.
[[Page 68458]]
Table 10--Shutdown Zones and Level B Harassment Zones
----------------------------------------------------------------------------------------------------------------
Shutdown zones m (ft) Level B
Method Pile size/type ------------------------------------------------ harassment
MF PW OW zones m (ft)
----------------------------------------------------------------------------------------------------------------
Pile Removal Activities
----------------------------------------------------------------------------------------------------------------
Vibratory Extraction.......... 18'' Octagonal 20 (66) 20 (66) 20 (66) 1,445 (4,742)
Concrete.
18''Steel Pipe.. 20 (66) 20 (66) 20 (66) 575 (1,888)
----------------------------------------------------------------------------------------------------------------
Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving........... 24'' Octagonal 20 (66) \1\ 70 (230) 20 (66) 117 (383)
Concrete.
14'' Square 20 (66) 20 (66) 20 (66) 25 (82)
Concrete.
Vibratory Hammer.............. 6'' Round Steel. 20 (66) 20 (66) 20 (66) 494 (1,619)
----------------------------------------------------------------------------------------------------------------
\1\ Level A ZOI buffered from 62.5 m up to 70 m.
Protected Species Observers
The placement of protected species observers (PSOs) during all pile
driving activities (described in the Proposed Monitoring and Reporting
section) would ensure that the entire shutdown zone is visible. Should
environmental conditions deteriorate such that the entire shutdown zone
would not be visible (e.g., fog, heavy rain), pile driving would be
delayed until the PSO is confident marine mammals within the shutdown
zone could be detected.
Pre-Activity Monitoring
Prior to the start of daily in-water construction activity, or
whenever a break in pile driving of 30 minutes or longer occurs, PSOs
would observe the shutdown and monitoring zones for a period of 30
minutes. The shutdown zone would be considered cleared when a marine
mammal has not been observed within the zone for that 30-minute period.
If a marine mammal is observed within the shutdown zones listed in
Table 10, pile driving activity would be delayed or halted. If work
ceases for more than 30 minutes, the pre-activity monitoring of the
shutdown zones would commence. A determination that the shutdown zone
is clear must be made during a period of good visibility (i.e., the
entire shutdown zone and surrounding waters must be visible to the
naked eye).
Soft-Start Procedures
Soft-start procedures provide additional protection to marine
mammals by providing warning and/or giving marine mammals a chance to
leave the area prior to the hammer operating at full capacity. For
impact pile driving, contractors would be required to provide an
initial set of three strikes from the hammer at reduced energy,
followed by a 30-second waiting period, then two subsequent reduced-
energy strike sets. Soft-start would be implemented at the start of
each day's impact pile driving and at any time following cessation of
impact pile driving for a period of 30 minutes or longer.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
Visual Monitoring
Marine mammal monitoring during pile driving activities would be
conducted by PSOs meeting NMFS' the following requirements:
<bullet> Independent PSOs (i.e., not construction personnel) who
have no other assigned tasks during monitoring periods would be used;
<bullet> At least one PSO would have prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization;
<bullet> Other PSOs may substitute education (degree in biological
science or related field) or training for experience; and
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator would be designated. The lead
observer would be required to have prior experience
[[Page 68459]]
working as a marine mammal observer during construction.
PSOs would 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.
The Navy would have at least two PSOs stationed at the best
possible vantage points in the project area to monitor during all pile
driving activities. If a PSO sights a marine mammal in the shutdown
zone, the PSO should alert the ``command'' PSO to notify the equipment
operator to shut down. If the ``command PSO'' does not respond, any PSO
has the authority to notify the need for a shutdown. If the ``command''
PSO calls for a shutdown, the ``command'' PSO will let the contractor
know when activities can re-commence. Additional PSOs may be employed
during periods of low or obstructed visibility to ensure the entirety
of the shutdown zones are monitored. A marine mammal monitoring plan
will be developed and submitted to NMFS for approval prior to
commencing in-water construction activities.
Reporting
A draft marine mammal monitoring report would be submitted to NMFS
within 90 days after the completion of pile driving activities, or 60
days prior to a requested date of issuance of any future IHAs for the
project, or other projects at the same location, whichever comes first.
The marine mammal report would include an overall description of work
completed, a narrative regarding marine mammal sightings, and
associated PSO data sheets. Specifically, the report would include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including: (a) How many and what type of piles were
driven or removed and the method (i.e., impact or vibratory); and (b)
the total duration of time for each pile (vibratory driving) number of
strikes for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring; and
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance.
PSOs would record all incidents of marine mammal occurrence,
regardless of distance from activity, and would document any behavioral
reactions in concert with distance from piles being driven or removed.
Specifically, PSOs will record the following:
<bullet> Name of PSO who sighted the animal(s) and PSO location and
activity at time of sighting;
<bullet> Time of sighting;
<bullet> Identification of the animal(s) (e.g., genus/species,
lowest possible taxonomic level, or unidentified), PSO confidence in
identification, and the composition of the group if there is a mix of
species;
<bullet> Distance and location of each observed marine mammal
relative to the pile being driven or hole being drilled for each
sighting;
<bullet> Estimated number of animals (min/max/best estimate);
<bullet> Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, etc.);
<bullet> Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching);
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
the species listed in Table 2, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. There is little information about the nature or severity of
the impacts, or the size, status, or structure of any of these species
or stocks that would lead to a different analysis for this activity.
Level A harassment is extremely unlikely given the small size of
the Level A harassment isopleths and the required mitigation measures
designed to minimize the possibility of injury to marine mammals. No
mortality is anticipated given the nature of the activity.
Pile installation and removal activities have the potential to
disturb or displace marine mammals. Specifically, the project
activities may result in take, in the form of Level A and Level B
harassment from underwater sounds generated from impact and vibratory
pile installation, and vibratory pile removal activities. Potential
takes could occur if individuals move into the ensonified zones when
these activities are underway.
The takes from Level B harassment would be due to potential
behavioral disturbance. No serious injury or mortality is anticipated
for any stocks presented in this analysis given the nature of the
activity and mitigation measures designed to minimize the
[[Page 68460]]
possibility of injury. The potential for harassment is minimized
through construction methods and the implementation of planned
mitigation strategies (see Proposed Mitigation section).
Take would occur within a limited, confined area of each stock's
range. Level B harassment would be reduced to the level of least
practicable adverse impact through use of mitigation measures described
herein. Further, the amount of take authorized is extremely small when
compared to stock abundance.
No marine mammal stocks for which incidental take authorization is
proposed are listed as threatened or endangered under the ESA or
determined to be strategic or depleted under the MMPA. The relatively
low marine mammal occurrences in the area, small shutdown zones, and
proposed monitoring make injury takes of marine mammals unlikely. The
shutdown zones would be thoroughly monitored before the proposed
vibratory pile installation and removal begins, and construction
activities would be postponed if a marine mammal is sighted within the
shutdown zone. There is a high likelihood that marine mammals would be
detected by trained observers under environmental conditions described
for the proposed project. Limiting construction activities to daylight
hours will also increase detectability of marine mammals in the area.
Therefore, the proposed mitigation and monitoring measures are expected
to eliminate the potential for injury and Level A harassment as well as
reduce the amount and intensity for Level B behavioral harassment.
Furthermore, the pile installation and removal activities analyzed here
are similar to, or less impactful than, numerous construction
activities conducted in other similar locations which have occurred
with no reported injuries or mortality to marine mammals, and no known
long-term adverse consequences from behavioral harassment.
Anticipated and authorized takes are expected to be limited to
short-term Level B harassment (behavioral disturbance) as construction
activities will occur over the course of 32 weeks. Effects on
individuals taken by Level B harassment, based upon reports in the
literature as well as monitoring from other similar activities, may
include increased swimming speeds, increased surfacing time, or
decreased foraging (e.g., Thorson and Reyff, 2006; NAVFAC SW, 2018b).
Individual animals, even if taken multiple times, will likely move away
from the sound source and be temporarily displaced from the area due to
elevated noise level during pile removal. Marine mammals could also
experience TTS if they move into the Level B monitoring zone. TTS is a
temporary loss of hearing sensitivity when exposed to loud sound, and
the hearing threshold is expected to recover completely within minutes
to hours. Thus, it is not considered an injury. While TTS could occur,
it is not considered a likely outcome of this activity. Repeated
exposures of individuals to levels of sounds that could cause Level B
harassment are unlikely to considerably significantly disrupt foraging
behavior or result in significant decrease in fitness, reproduction, or
survival for the affected individuals. In all, there would be no
adverse impacts to the stock as a whole.
The proposed project is not expected to have significant adverse
effects on marine mammal habitat. There are no Biologically Important
Areas or ESA-designated critical habitat within the project area, and
the proposed activities would not permanently modify existing marine
mammal habitat. The activities may cause fish to leave the area
temporarily. This could impact marine mammals' foraging opportunities
in a limited portion of the foraging range, however, due to the short
duration of activities and the relatively small area of affected
habitat, the impacts to marine mammal habitat are not expected to cause
significant or long-term negative consequences.
In combination, we believe that these factors, as well as the
available body of evidence from other similar activities, demonstrate
that the potential effects of the specified activities would have only
minor, short-term effects on individuals. The specified activities are
not expected to impact reproduction or survival of any individual
marine mammals, much less affect rates of recruitment or survival and
would therefore not result in population-level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality or Level A harassment is
anticipated or authorized;
<bullet> The specified activity and associated ensonified areas are
very small relative to the overall habitat ranges of all species;
<bullet> Biologically important areas or critical habitat have not
been identified within the project area;
<bullet> The lack of anticipated significant or long-term effects
to marine mammal habitat;
<bullet> The Navy is required to implement mitigation measures to
minimize impacts, such as PSO observation and shutdown zones of 20 m
(66 ft); 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 will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted previously, only small numbers of incidental take may be
authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
The amount of take NMFS proposes to authorize is below one-third of
the estimated stock abundances for all seven species (refer back to
Table 9). For most requested species, the proposed take of individuals
is less than 1 percent of the abundance of the affected stock (with
exception for bottlenose dolphins at 7.1 percent). This is likely a
conservative estimate because it assumes all takes are of different
individual animals, which is likely not the case. Some individuals may
return multiple times in a day, but PSOs would count them as separate
takes if they cannot be individually identified.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals,
[[Page 68461]]
NMFS preliminarily finds that small numbers of marine mammals would be
taken relative to the population size of the affected species or
stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA; 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species.
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to the U.S. Navy for conducting the NBPL Pier 302
Replacement Project in San Diego Bay from October 1, 2023 through
September 30, 2024, provided the previously mentioned mitigation,
monitoring, and reporting requirements are incorporated. A draft of the
proposed IHA can be found at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed
construction activities. We also request comment on the potential
renewal of this proposed IHA as described in the paragraph below.
Please include with your comments any supporting data or literature
citations to help inform decisions on the request for this IHA or a
subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activities section of this notice is planned or (2) the activities as
described in the Description of Proposed Activities section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<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);
and
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: November 9, 2022.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2022-24847 Filed 11-14-22; 8:45 am]
BILLING CODE 3510-22-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.