[Federal Register Volume 85, Number 105 (Monday, June 1, 2020)]
[Notices]
[Pages 33129-33139]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-11732]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XR106]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Floating Dry Dock Project at
Naval Base San Diego in San Diego, California
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; Issuance of an Incidental Harassment Authorization.
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA), as amended, notification is hereby given
that NMFS has issued an incidental harassment authorization (IHA) to
the U.S. Navy (Navy) to incidentally take, by Level B harassment, one
species of marine mammal during the Floating Dry Dock Project at Naval
Base San Diego in San Diego, California.
DATES: This Authorization is effective from September 15, 2020 through
September 14, 2021.
FOR FURTHER INFORMATION CONTACT: Wendy Piniak, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the
authorization, application, and supporting documents, as well as a list
of the references cited in this document, may be obtained online at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of
problems accessing these documents, please call the contact listed
above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed IHA may be provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and 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.
Summary of Request
On November 26, 2019, NMFS received a request from the Navy for an
IHA to take marine mammals incidental to the Floating Dry Dock Project
at Naval Base San Diego in San Diego, California. We received a revised
application on February 10, 2020. The application was deemed adequate
and complete on March 17, 2020. The Navy's request is for take of a
small number of California sea lions by Level B harassment only.
Neither the Navy nor NMFS expects serious injury or mortality to result
from this activity and, therefore, an IHA is appropriate.
Description of Activity
Overview
The Navy requested authorization for take of marine mammals
incidental to in-water activities associated with the Floating Dry Dock
Project at Naval Base San Diego in San Diego, California. The Navy
plans to construct a floating dry dock and associated pier-side access
in the south-central portion of San Diego Bay. The floating dry dock is
needed to ensure the Naval Base San Diego's capability to conduct
berth-side repair and maintenance of vessels. Implementation of the
project requires installation of two mooring dolphins, including
vertical and angled structural piles, as well as fender piles,
installation of a concrete ramp wharf and vehicle bridge, and dredging
at the floating dry dock location. In-water construction will include
installation of a maximum of 56 24-inch concrete piles using impact
pile driving and high-pressure water jetting and a maximum of 20 24-
inch steel pipe piles using impact and vibratory pile driving. Sounds
produced by these activities may result in take, by Level B harassment,
of marine mammals located in San Diego Bay, California. In-water pile-
driving activities are anticipated to occur for 60 days during the
period from September 15, 2020 to September 14, 2021.
Dates and Duration
In-water activities (pile installation) associated with the project
are anticipated to begin September 15, 2020, and be completed by
September 14, 2021. Pile driving activities will occur for 60 days
during the planned project dates. In-water activities will occur during
daylight hours only.
Detailed Description of Specific Activity
A detailed description of the planned activities is provided in the
Federal Register notice announcing the proposed IHA (85 FR 21179; April
16, 2020). Since that time, the Navy has revised the number of 24-inch
steel pipe piles required for the project (and therefore the number of
days required to complete the project), and the revised description of
this component of the project (construction of two mooring dolphins) is
provided below. No other revisions have been made to the Navy's planned
activities. Please refer to the proposed IHA Federal Register notice
for a detailed description of the activity.
The Navy will construct a floating dry dock and associated pier-
side access in the south-central portion of San Diego Bay.
Implementation of the project requires in-water activities that will
produce sounds that may result in take of marine mammals located in the
San Diego Bay including dredging, installation of two mooring dolphins,
including vertical and angled structural
[[Page 33130]]
piles, as well as fender piles, and installation of a concrete ramp
wharf and vehicle bridge. Two mooring dolphins will be located forward
and aft of the dry dock. The mooring dolphins will each be supported by
up to 16 vertical 24-inch octagonal concrete piles (32 total) installed
using impact pile driving and high-pressure water jetting. The aft
mooring dolphin would also require approximately two 24-inch angled
steel pipe piles. Up to eight additional 24-inch steel pipe piles are
anticipated to be required for each of the forward and aft mooring
dolphins (16 total, rather than the 8 described in the Federal Register
notice announcing the proposed IHA (85 FR 21179; April 16, 2020)).
Cast-in-place reinforced concrete caps, 9.1 by 9.1 m (30 by 30 ft),
will be installed at each mooring dolphin location. Grippers will be
secured to the dolphins' concrete pile caps and used to hold the
floating dry dock in position. Construction materials will be delivered
by truck and the piles would be installed using a floating crane and an
impact or vibratory pile driver aided by jetting methods. Fender piles
associated with the aft mooring dolphin will consist of two steel pipe
piles, 24-inches in diameter or less. All steel pipe piles will
initially be installed using vibratory pile driving, followed by the
use of an impact pile driver.
Pile driving activities are planned to occur from September 15,
2020 through September 14, 2021. The total number of pile driving days
will not exceed 60 days (rather than the 50 days described in the
Federal Register notice announcing the proposed IHA (85 FR 21179; April
16, 2020)) during this time period.
Mitigation, monitoring, and reporting measures are described in
detail later in this document (please see Mitigation and Monitoring and
Reporting).
Comments and Responses
A notice of NMFS' proposal to issue an IHA to the Navy was
published in
the Federal Register on April 16, 2020 (85 FR 21179). That notice
described, in detail, the Navy's proposed activity, the marine mammal
species that may be affected by the activity, the anticipated effects
on marine mammals and their habitat, proposed amount and manner of
take, and proposed mitigation, monitoring and reporting measures.
During the 30-day public comment period NMFS received a comment letter
from the Marine Mammal Commission (Commission); the Commission's
recommendations and our responses are provided here, and the comments
have been posted online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.
Comment 1: The Commission recommends that NMFS revise its standard
condition for ceasing in-water heavy machinery activities (Condition
4(a) in the IHA) to include, as examples, movement of the barge to the
pile location, positioning of the pile on the substrate, use of barge-
mounted excavators, and dredging in all draft and final incidental take
authorizations.
Response: NMFS appreciates the recommendation but disagrees that a
comprehensive listing of potential activities for which the measure is
appropriate is necessary, and does not adopt the recommendation.
Comment 2: The Commission notes that the Level B harassment zone is
more than 2.5 km for vibratory pile driving and more than 1.8 km during
impact driving of 24-inch piles. In both circumstances, California sea
lions would not be sighted at the extents of the Level B harassment
zones if only one Protected Species Observer (PSO) was located at the
pile-driving location in the near field. They note that a second
vessel-based PSO should monitor the extent of the Level B harassment
zone during impact pile driving as well as during vibratory pile
driving. Given that impact pile driving of 24-inch steel piles would
occur after the piles have been driven with the vibratory hammer, it
would be practicable for the vessel-based PSO to remain on station and
continue to monitor until impact pile driving is finished and the pile
is driven to depth. The Commission recommends that NMFS include in
condition 5(a) of the final authorization the requirement that the Navy
use one land-based and one-vessel-based PSO to monitor for marine
mammals during both vibratory and impact pile driving of 24-inch steel
piles.
Response: NMFS disagrees with the Commission's rationale and
assertion that the measure is practicable, and does not adopt the
recommendation. We have included in the authorization that the Navy
must include extrapolation of the estimated takes by Level B harassment
based on the number of observed exposures within the Level B harassment
zone and the percentage of the Level B harassment zone that was not
visible in the draft and final reports. Though as the Commission notes,
vibratory and impact pile driving may occur in succession, this may not
always be the case (for example, when switching hammer types). Given
the condition to extrapolate takes, it is not necessary to require that
the entire Level B zone be visible or monitored during all activities.
Comment 3: The Commission noted that NMFS indicated in the Federal
Register notice that pile installation would only occur during daylight
hours and that pile driving would only be conducted at least 30 minutes
after sunrise and up to 30 minutes before sunset, when visual
monitoring of marine mammals can be conducted. However, they stated
that NMFS did not stipulate in the draft authorization that activities
must occur during daylight hours only, nor that activities must be
conducted during periods of good visibility and stated that, if poor
environmental conditions restrict full visibility of the shutdown zone,
pile installation must be delayed. The Commission recommends that NMFS
include (1) in the final authorization the requirements that the Navy
conduct pile-driving activities during daylight hours only and, if the
entire shut-down zone(s) is not visible, delay or cease pile-driving
activities until the zone(s) is visible and (2) standard conditions
consistently in all draft and final authorizations involving pile-
driving activities.
Response: We do not fully concur with the Commission's
recommendations, or with their underlying justification, and do not
adopt them as stated. While the Navy has no intention of conducting
pile driving activities at night, it is unnecessary to preclude such
activity should the need arise (e.g., on an emergency basis or to
complete driving of a pile begun during daylight hours, should the
construction operator deem it necessary to do so). Further, as stated
above, while acknowledging that prescribed mitigation measures for any
specific action (and an associated determination that the prescribed
measures are sufficient to achieve the least practicable adverse impact
on the affected species or stocks and their habitat) are subject to
review by the Commission and the public, any determination of what
measures constitute ``standard'' mitigation requirements is NMFS' alone
to make. Even in the context of measures that NMFS considers to be
``standard'' we reserve the flexibility to deviate from such measures,
depending on the circumstances of the action. We disagree with the
statement that a prohibition on pile driving activity outside of
daylight hours is necessary to meet the MMPA's least practicable
adverse impact standard, and the Commission does not justify this
assertion.
Comment 4: The Commission states that it is unclear from both the
preamble
[[Page 33131]]
and the draft authorization whether the Navy will keep a running tally
of the total Level B harassment takes, including observed and
extrapolated takes. They state that it is imperative that the Navy do
so to ensure that the takes are within the authorized limits and the
authorized numbers of takes are not exceeded to implement effectively
condition 4(h) in the draft authorization. The Commission recommends
that NMFS ensure that the Navy keeps a running tally of the total
takes, based on observed and extrapolated takes, for Level B harassment
consistent with condition 4(h) of the final authorization.
Response: We agree that the Navy must ensure they do not exceed
authorized takes but do not concur with the recommendation. NMFS is not
responsible for ensuring that the Navy does not operate in violation of
an issued IHA.
Comment 5: The Commission recommended that NMFS refrain from
issuing renewals for any authorization and instead use its abbreviated
Federal Register notice process, which is similarly expeditious and
fulfills NMFS's intent to maximize efficiencies. If NMFS continues to
propose to issue renewals, the Commission recommends that it (1)
stipulate that a renewal is a one-time opportunity (a) in all Federal
Register notices requesting comments on the possibility of a renewal,
(b) on its web page detailing the renewal process, and (c) in all draft
and final authorizations that include a term and condition for a
renewal and, (2) if NMFS declines to adopt this recommendation, explain
fully its rationale for not doing so.
Response: NMFS does not agree with the Commission and, therefore,
does not adopt the Commission's recommendation. NMFS will provide a
detailed explanation of its decision within 120 days, as required by
section 202(d) of the MMPA.
Description of Marine Mammals in the Area of Specified Activities
A detailed description of the species likely to be affected by the
Navy's project, including brief introductions to the species and
relevant stocks as well as available information regarding population
trends and threats, and information regarding local occurrence, were
provided in the Federal Register notice for the proposed IHA (85 FR
21179; April 16, 2020). Since that time, we are not aware of any
changes in the status of these species and stocks; therefore, detailed
descriptions are not provided here. Please refer to the proposed IHA
Federal Register notice for these descriptions; we provide a summary of
marine mammals that may potentially be present in the project area here
(Table 1). Additional information regarding population trends and
threats may be found in NMFS' Stock Assessment Reports (SAR; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS'
website (https://www.fisheries.noaa.gov/find-species).
Table 1 lists all species or stocks for which take is expected and
authorized for this action, and summarizes information related to the
population or stock, including regulatory status under the MMPA and the
Endangered Species Act (ESA) and potential biological removal (PBR),
where known. For taxonomy, we follow Committee on Taxonomy (2019). PBR
is defined by the MMPA as the maximum number of animals, not including
natural mortalities, that may be removed from a marine mammal stock
while allowing that stock to reach or maintain its optimum sustainable
population (as described in NMFS's SARs). While no mortality is
anticipated or authorized here, PBR and annual serious injury and
mortality from anthropogenic sources are included here as gross
indicators of the status of the species and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Pacific Stock Assessment Reports (e.g., Carretta et al.,
2019). All values presented in Table 1 are the most recent available at
the time of publication and are available in the 2018 Final SARs
(Carretta et al., 2019) (available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments).
Table 1--Marine Mammals Potentially Present Within Central San Diego, California During the Specified Activity
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ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock Strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
sea lions):
California sea lion............. Zalophus californianus. U.S.................... -, -, N 257,606 (N/A, 233,515, 14,011 >321
2014).
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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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. California sea lion
population size was estimated from a 1975-2014 time series of pup counts (Lowry et al., 2017), combined with mark-recapture estimates of survival
rates (DeLong et al., 2017, Laake et al., 2018).
\3\ These values, found in NMFS' 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.
[[Page 33132]]
Habitat
No ESA-designated critical habitat or Biologically Important Areas
overlap with the project area.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
Underwater noise from impact and vibratory pile driving activities
associated with the planned Floating Dry Dock Project at Naval Base San
Diego have the potential to result in harassment of marine mammals in
the vicinity of the action area. The Federal Register notice for the
proposed IHA (85 FR 21179; April 16, 2020) included a discussion of the
potential effects of such disturbances on marine mammals and their
habitat, therefore that information is not repeated in detail here;
please refer to the Federal Register notice (85 FR 21179; April 16,
2020) for that information.
Estimated Take
This section provides an estimate of the number of incidental takes
authorized through this IHA, which will inform both NMFS' consideration
of ``small numbers'' and the negligible impact determination.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes will be by Level B harassment only, in the form of
disruption of behavioral patterns for individual California sea lions
resulting from exposure to pile driving activities. Based on the nature
of the activity and the anticipated effectiveness of the mitigation
measures (i.e., shutdown)--discussed in detail below in Mitigation
section, Level A harassment is neither anticipated nor authorized.
As described previously, no mortality is anticipated or authorized
for this activity. Below we describe how the take is estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals 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)
and the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring results or average group size). Below, we describe the
factors considered here in more detail and present the take estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed 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
permanent threshold shift (PTS) of some degree (equated to Level A
harassment).
Level B Harassment for non-explosive sources--Though significantly
driven by received level, the onset of behavioral disturbance from
anthropogenic noise exposure is also informed to varying degrees by
other factors related to the source (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on what the available science indicates
and the practical need to use a threshold based on a factor that is
both predictable and measurable for most activities, NMFS uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS predicts that marine mammals are
likely to be behaviorally harassed in a manner we consider Level B
harassment when exposed to underwater anthropogenic noise above
received levels of 120 decibels (dB) re: 1 micropascal ([mu]Pa) root
mean square (rms) for continuous (e.g., vibratory pile-driving,
drilling) and above 160 dB re: 1 [mu]Pa (rms) for non-explosive
impulsive (e.g., seismic airguns) or intermittent (e.g., scientific
sonar) sources.
Navy's activity includes the use of continuous (vibratory pile
driving) and impulsive (impact pile driving) sources, and therefore the
120 and 160 dB re: 1 [mu]Pa (rms) thresholds are applicable. However,
background (ambient) noise in the south-central San Diego Bay was
measured at 126 dB re: 1 [mu]Pa (L50) in 2019 (Dahl and Dall'Osto
2019), therefore, 126 dB re: 1 [mu]Pa was used to calculate the Level B
harassment isopleth.
Level A harassment for non-explosive sources--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). Navy's planned activity includes the use
includes the use of continuous (vibratory pile driving) and impulsive
(impact pile driving) 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
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 2--Thresholds Identifying the Onset of Permanent Threshold Shift
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PTS onset thresholds \*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
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Low-Frequency (LF) Cetaceans........... Lp,0-pk,flat: 219 dB; LE,p,LF,24h: 199 dB.
LE,p,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Lp,0-pk,flat: 230 dB; LE,p,MF,24h: 198 dB.
LE,p,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Lp,0-pk,flat: 202 dB; LE,p,HF,24h: 173 dB.
LE,p,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Lp,0-pk.flat: 218 dB; LE,p,PW,24h: 201 dB.
LE,p,PW,24h: 185 dB.
[[Page 33133]]
Otariid Pinnipeds (OW) (Underwater).... Lp,0-pk,flat: 232 dB; LE,p,OW,24h: 219 dB.
LE,p,OW,24h: 203 dB.
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\*\ Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating
PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds
associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
hearing range of marine mammals (i.e., 7 Hz to 160 kHz). The subscript associated with cumulative sound
exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF
cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted
cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e., varying exposure
levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the
conditions under which these thresholds will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the project. Pile driving
generates underwater noise that can potentially result in disturbance
to marine mammals in the project area. The maximum (underwater) area
ensonified is determined by the topography of the San Diego Bay
including hard structures directly to the south of the project site.
Additionally, vessel traffic and other commercial and industrial
activities in the project area may contribute to elevated background
noise levels which may mask sounds produced by the project.
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
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log[range]). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting in a reduction of 3 dB in sound level
for each doubling of distance from the source (10*log[range]). A
practical spreading value of fifteen is often used under conditions,
such as the project site where water increases with depth as the
receiver moves away from the shoreline, resulting in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions. Practical spreading loss is
assumed here.
The intensity of pile driving sounds is greatly influenced by
factors such as the type of piles, hammers, and the physical
environment in which the activity takes place. In order to calculate
distances to the Level A harassment and Level B harassment thresholds
for the 24-inch octagonal concrete piles and the 24-inch steel pipe
piles planned in this project, acoustic monitoring data from other
locations were used. Empirical data from recent sound source
verification (SSV) studies reported in CALTRANS (2015) were used to
estimate sound source levels (SSLs) for impact pile driving. For impact
pile driving of 24-inch octagonal concrete piles measurements from San
Francisco Bay, California were used (SELs-s: 166 dB re: 1 [mu]Pa\2\s;
SPLrms: 176 dB re: 1 [mu]Pa; SPLpeak: 188 dB re: 1 [mu]Pa) (CALTRANS,
2015). For impact pile driving of 24-inch steel pipe piles measurements
from Carquinez Bay, California were used (SELs-s: 178 dB re: 1
[mu]Pa\2\s; SPLrms: 194 dB re: 1 [mu]Pa; SPLpeak: 207 dB re: 1 [mu]Pa)
(CALTRANS, 2015). For vibratory pile driving of 24-inch steel pipe
piles, average data collected from four projects (three in Washington
and one in California) involving 16 and 24-inch piles reported by
United States Navy (2015) were used. The highest project average SPLrms
of 162 dB re: 1 [mu]Pa was selected as the most reasonable proxy for
24-inch steel pipe piles.
For piles requiring use of vibratory pile driving, it is
anticipated that 10 minutes (min) per pile will be required. The number
of final strikes via impact pile driving for each pile installed would
be dependent on the underlying geology and the exact placement of the
pile. For example, pile-driving activities associated with the Pier 12
replacement required between 500 and 600 blows per pile (Alberto
Sanchez 2019, personal communication). To be conservative, 600 strikes
per pile is estimated for impact pile driving.
Navy used NMFS' Optional User Spreadsheet, available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance, to input project-specific parameters and
calculate the isopleths for the Level A harassment zones for impact and
vibratory pile driving. When the NMFS Technical Guidance (2018) was
published, in recognition of the fact that ensonified area/volume could
be more technically challenging to predict because of the duration
component in the new thresholds, we developed a User Spreadsheet that
includes tools to help predict a simple isopleth that can be used in
conjunction with marine mammal density or occurrence to help predict
takes. We note that because of some of the assumptions included in the
methods used for these tools, we anticipate that isopleths produced are
typically going to be overestimates of some degree, which may result in
some
[[Page 33134]]
degree of overestimate of Level A harassment take. However, these tools
offer the best way to predict appropriate isopleths when more
sophisticated 3D modeling methods are not available, and NMFS continues
to develop ways to quantitatively refine these tools, and will
qualitatively address the output where appropriate. For stationary
sources pile driving, the User Spreadsheet predicts the distance at
which, if a marine mammal remained at that distance the whole duration
of the activity, it would incur PTS.
Table 3 provides the sound source values and input used in the User
Spreadsheet to calculate harassment isopleths for each source type. For
impact pile driving, isopleths calculated using the cumulative SEL
metric (SELs-s) will be used as it produces larger isopleths than
SPLpeak. Isopleths for Level B harassment associated with impact pile
driving (160 dB) and vibratory pile driving (126 dB) were also
calculated and can be found in Table 4.
Table 3--User Spreadsheet Input Parameters Used for Calculating Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
Impact pile driving 24- Vibratory pile driving
User Spreadsheet Parameter inch octagonal Impact pile driving 24- 24-inch steel pipe
concrete piles inch steel pipe piles piles
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used................. (E.1) Impact pile (E.1) Impact pile (A.1) Vibratory pile
driving. driving. driving
Source Level (SELs-s or SPL rms)..... 166 SELs-s \a\......... 178 SELs-s \a\......... 162 dB SPL rms \b\
Source Level (SPLpeak)............... 188.................... 207.................... N/A
Weighting Factor Adjustment (kHz).... 2...................... 2...................... 2.5
Number of piles per day.............. 3...................... 1...................... 1
Number of strikes per pile........... 600.................... 600.................... N/A
Number of strikes per day............ 1,800.................. 600.................... N/A
Estimate driving duration (min) per N/A.................... N/A.................... 10
pile.
Activity Duration (h) within 24-h N/A.................... N/A.................... 0.167
period.
Propagation (xLogR).................. 15 Log R............... 15 Log R............... 15 Log R
Distance of source level measurement 10..................... 10..................... 10
(meters).
----------------------------------------------------------------------------------------------------------------
\a\ CATRANS, 2015.
\b\ United States Navy, 2015.
Table 4--Calculated Distances to Level A Harassment and Level B Harassment Isopleths During Pile Driving
----------------------------------------------------------------------------------------------------------------
Level A Level B Level B
harassment zone harassment zone harassment zone
(meters) (meters) ensonified area
Source -------------------------------------- (km\2\)
------------------
Otariid pinnipeds Pinnipeds Pinnipeds
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving 24-inch octagonal concrete piles... 4 117 0.043
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving 24-inch steel pipe piles........... 13 1,848 3.68
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving 24-inch steel pipe piles........ <1 2,512 6.94
----------------------------------------------------------------------------------------------------------------
Source PTS onset
isopleth--Peak
(meters)
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving 24-inch octagonal concrete piles... N/A
----------------------------------------------------------------------------------------------------------------
Impact Pile Driving 24-inch steel pipe piles........... N/A
----------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations, and how this information is brought together to produce a
quantitative take estimate.
No California sea lion density information is available for south
San Diego Bay. Potential exposures to impact and vibratory pile driving
noise for each threshold for California sea lions were estimated using
data collected during a 2010 survey as reported in Sorensen and Swope
(2010). The Sorenson and Swope (2010) survey is the only known survey
to provide marine mammal observation data below the San Diego Coronado
Bridge (in mid San Diego Bay). The single survey was on February 16,
2010. During this survey one single sea lion was observed off Pier 3
and one single sea lion was observed ~600 m from the project site.
Level B Harassment Calculations
The following equation was used to calculate takes by Level B
harassment:
Level B harassment estimate = N (number of animals in the ensonified
area) * Number of days of noise generating activities.
The available survey data suggests from Sorenson and Swope (2010)
suggests two California sea lions could be present each day in the
project area, however given the limited data available, to be
conservative we have estimated four California sea lions could be
present each day.
Level B harassment estimate = 4 (number of animals in the ensonified
area) * 60 (Number of days of noise generating activities) = 240.
[[Page 33135]]
Note that after the publication of the proposed IHA, the Navy
reevaluated the number of required 24-inch steel pipe piles, increasing
the maximum number from 10 to 20 24-inch steel pipe piles. This
increased the maximum number of days of the project activity from 50
(as presented in the proposed IHA) to 60, and therefore has increased
the estimated number of California sea lion takes by Level B harassment
from 200 (as presented in the proposed IHA) to 240.
Level A Harassment Calculations
Navy intends to avoid Level A harassment take by shutting down
activities if a California sea lion approaches with 25 m of the project
site, which encompasses all Level A harassment (PTS onset)
ensonification zones described in Table 4. Therefore, no take by Level
A harassment is anticipated or authorized.
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, we
carefully consider two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure 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, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
In addition to the measures described later in this section, Navy
will employ the following standard mitigation measures:
Conduct briefings between construction supervisors and
crews and the marine mammal monitoring team prior to the start of all
pile driving activity, and when new personnel join the work, to explain
responsibilities, communication procedures, marine mammal monitoring
protocol, and operational procedures;
For in-water heavy machinery work other than pile driving
(e.g., standard barges, etc.), if a marine mammal comes within 10 m,
operations shall cease and vessels shall reduce speed to the minimum
level required to maintain steerage and safe working conditions. This
type of work could include the following activities: (1) Movement of
the barge to the pile location; or (2) positioning of the pile on the
substrate via a crane (i.e., stabbing the pile);
Though not required, Navy has indicated that in-water pile
driving will only be conducted at least 30 minutes after sunrise and up
to 30 minutes before sunset, when visual monitoring of marine mammals
can be conducted;
For those marine mammals for which Level B harassment take
has not been requested, in-water pile driving will shut down
immediately if such species are observed within or entering the
monitoring zone (i.e., Level B harassment zone); and
If take reaches the authorized limit for an authorized
species, pile installation will be stopped as these species approach
the Level B harassment zone to avoid additional take.
The following measures apply to Navy's mitigation requirements:
Establishment of Shutdown Zone for Level A Harassment--For all pile
driving activities, Navy will establish a shutdown zone. The purpose of
a shutdown zone is generally to define an area within which shutdown of
activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). Conservative
shutdown zones of 25 m for impact and vibratory pile driving activities
would be implemented for California sea lions. The placement of PSOs
during all pile driving activities (described in detail in the
Monitoring and Reporting section) will ensure shutdown zones are
visible.
Establishment of Monitoring Zones for Level B Harassment--Navy will
establish monitoring zones to correlate with Level B harassment zones
which are areas where SPLs are equal to or exceed the 160 dB re: 1
[micro]Pa (rms) threshold for impact pile driving and the 126 dB re: 1
[micro]Pa (rms) threshold during vibratory pile driving (Table 5).
Monitoring zones provide utility for observing by establishing
monitoring protocols for areas adjacent to the shutdown zones.
Monitoring zones enable observers to be aware of and communicate the
presence of marine mammals in the project area outside the shutdown
zone and thus prepare for a potential cease of activity should the
animal enter the shutdown zone.
Table 5--Monitoring and Shutdown Zones for Each Project Activity
------------------------------------------------------------------------
Monitoring zone Shutdown zone
Source (m) (m)
------------------------------------------------------------------------
Impact Pile Driving 4-inch 120 25
octagonal concrete piles.........
Impact Pile Driving 24-inch steel 1,850 25
pipe piles.......................
Vibratory Pile Driving 24-inch 2,515 25
steel pipe piles.................
------------------------------------------------------------------------
Soft Start--The use of soft-start procedures are believed to
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
will be required to provide an initial set of strikes from
[[Page 33136]]
the hammer at reduced energy, with each strike followed by a 30-second
waiting period. This procedure will be conducted a total of three times
before impact pile driving begins. Soft start will 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.
Soft start is not required during vibratory pile driving activities.
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 will observe the shutdown and monitoring
zones for a period of 30 minutes. The shutdown zone will be 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 zone,
a soft-start cannot proceed until the animal has left the zone or has
not been observed for 15 minutes. If the Level B harassment zone has
been observed for 30 minutes and non-permitted species are not present
within the zone, soft start procedures can commence and work can
continue even if visibility becomes impaired within the Level B
harassment monitoring zone. When a marine mammal permitted for take by
Level B harassment is present in the Level B harassment zone,
activities may begin and Level B harassment take will be recorded. If
work ceases for more than 30 minutes, the pre-activity monitoring of
both the Level B harassment and shutdown zone will commence again.
Due to strong tidal fluctuations and associated currents in San
Diego Bay, bubble curtains will not be implemented as they would not be
effective in this environment.
Based on our evaluation of the applicant's planned measures, NMFS
has determined that the mitigation measures provide the means 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.
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 in the
action area. Effective reporting is critical both to compliance as well
as ensuring that the most value is obtained from the required
monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
Marine Mammal Visual Monitoring
Monitoring shall be conducted by NMFS-approved observers. Trained
observers shall be placed from the best vantage point(s) practicable to
monitor for marine mammals and implement shutdown or delay procedures
when applicable through communication with the equipment operator.
Observer training must be provided prior to project start, and shall
include instruction on species identification (sufficient to
distinguish the species in the project area), description and
categorization of observed behaviors and interpretation of behaviors
that may be construed as being reactions to the specified activity,
proper completion of data forms, and other basic components of
biological monitoring, including tracking of observed animals or groups
of animals such that repeat sound exposures may be attributed to
individuals (to the extent possible).
Monitoring will be conducted 30 minutes before, during, and 30
minutes after pile driving activities. In addition, observers shall
record all incidents of marine mammal occurrence, regardless of
distance from activity, and shall document any behavioral reactions in
concert with distance from piles being driven. Pile driving activities
include the time to install a single pile or series of piles, as long
as the time elapsed between uses of the pile driving equipment is no
more than 30 minutes.
At least one land-based PSO will be located at the project site,
and for the Navy has indicated that when possible and appropriate
during vibratory pile driving activities, one additional boat-based PSO
will be located at the edge of the Level B harassment isopleth (see
Figure 1-2 of the Marine Mammal Monitoring Plan dated March, 2020).
PSOs will scan the waters using binoculars, and/or spotting scopes,
and will use a handheld GPS or range-finder device to verify the
distance to each sighting from the project site. All PSOs will be
trained in marine mammal identification and behaviors and are required
to have no other project-related tasks while conducting monitoring. In
addition, monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable to monitor for
marine mammals and implement shutdown/delay procedures when applicable
by calling for the shutdown to the hammer operator. Navy would adhere
to the following PSO qualifications:
(i) Independent observers (i.e., not construction personnel) are
required;
(ii) At least one observer must have prior experience working as an
observer;
(iii) Other observers may substitute education (degree in
biological science or related field) or training for experience;
(iv) Where a team of three or more observers are required, one
observer shall be designated as lead observer or monitoring
coordinator. The lead observer must have prior experience working as an
observer; and
(v) Navy shall submit observer Curriculum vitaes for approval by
NMFS. Additional standard observer qualifications include:
Ability to conduct field observations and collect data
according to assigned protocols;
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
[[Page 33137]]
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates and times when in-water construction
activities were suspended to avoid potential incidental injury from
construction sound of marine mammals observed within a defined shutdown
zone; and marine mammal behavior; and
Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Observers will be required to use approved data forms (see data
collection forms in the applicant's Marine Mammal Mitigation and
Monitoring Plan). Among other pieces of information, Navy will record
detailed information about any implementation of shutdowns, including
the distance of animals to the pile and description of specific actions
that ensued and resulting behavior of the animal, if any. In addition,
Navy will attempt to distinguish between the number of individual
animals taken and the number of incidences of take. We require that, at
a minimum, the following information be collected on the sighting
forms:
Dates and times (begin and end) of all marine mammal
monitoring;
Construction activities occurring during each daily
observation period, including how many and what type of piles were
driven or removed and by what method (i.e., impact or vibratory);
Weather parameters and water conditions during each
monitoring period (e.g., wind speed, percent cover, visibility, sea
state);
The number of marine mammals observed, by species,
relative to the pile location and if pile driving or removal was
occurring at time of sighting;
Age and sex class, if possible, of all marine mammals
observed;
PSO locations during marine mammal monitoring;
Distances and bearings of each marine mammal observed to
the pile being driven or removed for each sighting (if pile driving or
removal was occurring at time of sighting);
Description of any marine mammal behavior patterns during
observation, including direction of travel and estimated time spent
within the Level A and Level B harassment zones while the source was
active;
Number of individuals of each species (differentiated by
month as appropriate) detected within the monitoring zone, and
estimates of number of marine mammals taken, by species (a correction
factor may be applied to total take numbers, as appropriate);
Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting behavior of the animal, if
any;
Description of attempts to distinguish between the number
of individual animals taken and the number of incidences of take, such
as ability to track groups or individuals;
An extrapolation of the estimated takes by Level B
harassment based on the number of observed exposures within the Level B
harassment zone and the percentage of the Level B harassment zone that
was not visible; and
Submit all PSO datasheets and/or raw sighting data (in a
separate file from the final report referenced immediately above).
A draft report will be submitted to NMFS within 90 days of the
completion of marine mammal monitoring, or 60 days prior to the
requested date of issuance of any future IHA for projects at the same
location, whichever comes first. The report will include marine mammal
observations pre-activity, during-activity, and post-activity during
pile driving days (and associated PSO data sheets), and will also
provide descriptions of any behavioral responses to construction
activities by marine mammals and a complete description of all
mitigation shutdowns and the results of those actions and an
extrapolated total take estimate based on the number of marine mammals
observed during the course of construction. A final report must be
submitted within 30 days following resolution of comments on the draft
report.
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the IHA-holder shall report
the incident to the Office of Protected Resources (OPR) (301-427-8401),
NMFS and to the West Coast Region Stranding Coordinator (562-980-3230)
as soon as feasible. If the death or injury was clearly caused by the
specified activity, the IHA-holder must immediately cease the specified
activities until NMFS is able to review the circumstances of the
incident and determine what, if any, additional measures are
appropriate to ensure compliance with the terms of the IHA. The IHA-
holder must not resume their activities until notified by NMFS. The
report must include the following information:
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive;
If available, photographs or video footage of the
animal(s); and
General circumstances under which the animal was
discovered.
NMFS will work with Navy to determine what, if anything, is
necessary to minimize the likelihood of further prohibited take and
ensure MMPA compliance. Navy must not resume their activities until
notified by NMFS.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat, and the likely effectiveness
of the mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing
[[Page 33138]]
sources of human-caused mortality, or ambient noise levels).
Pile driving activities associated with the Floating Dry Dock
Project, as outlined previously, have the potential to disturb or
displace marine mammals. Specifically, the specified activities may
result in take, in the form of Level B harassment (behavioral
disturbance) from underwater sounds generated from impact and vibratory
pile driving. Potential takes could occur if individuals of California
sea lions are present in the ensonified zone when these activities are
underway.
No mortality or Level A harassment is anticipated or authorized
given the nature of the activity and measures designed to minimize the
possibility of injury to marine mammals. The potential for harassment
is minimized through the construction method and the implementation of
the planned mitigation measures (see Mitigation section).
The Navy's activities are localized and of relatively short
duration (a maximum of 60 days of pile driving for 76 piles). The
project area is also very limited in scope spatially, as all work is
concentrated on a single pier. Localized and short-term noise exposures
produced by project activities may cause short-term behavioral
modifications in pinnipeds. Moreover, the planned mitigation and
monitoring measures are expected to further reduce the likelihood of
injury, as it is unlikely an animal would remain in close proximity to
the sound source, as well as reduce behavioral disturbances.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, will likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring) (e.g., Thorson and Reyff,
2006; HDR, Inc., 2012; Lerma, 2014; ABR, 2016). Most likely,
individuals will move away from the sound source and be temporarily
displaced from the areas of pile driving, although even this reaction
has been observed primarily only in association with impact pile
driving. The pile driving activities analyzed here are similar to, or
less impactful than, numerous other construction activities conducted
in California, which have taken place with no known long-term adverse
consequences from behavioral harassment. Level B harassment will be
reduced to the level of least practicable adverse impact through use of
mitigation measures described herein and, if sound produced by project
activities is sufficiently disturbing, animals are likely to simply
avoid the area while the activity is occurring. While vibratory pile
driving associated with the project may produce sounds above ambient at
distances of several kilometers from the project site, thus intruding
on some habitat, the project site itself is located in an
industrialized bay, and sounds produced by the planned activities are
anticipated to quickly become indistinguishable from other background
noise in San Diego Bay as they attenuate to near ambient SPLs moving
away from the project site. Therefore, we expect that animals annoyed
by project sound would simply avoid the area and use more-preferred
habitats.
The project is also not expected to have significant adverse
effects on affected marine mammal habitat. The project activities will
not modify existing marine mammal habitat for a significant amount of
time. The activities may cause some fish to leave the area of
disturbance, thus temporarily impacting marine mammal foraging
opportunities in a limited portion of the foraging range. However,
because of the short duration of the activities, the relatively small
area of the habitat that may be affected, the impacts to marine mammal
habitat are not expected to cause significant or long-term negative
consequences.
In summary and as described above, the following factors primarily
support our determination that the impacts resulting from this activity
are not expected to adversely affect the species or stock through
effects on annual rates of recruitment or survival:
No mortality or Level A harassment is anticipated or
authorized;
The anticipated incidents of Level B harassment consist
of, at worst, temporary modifications in behavior that would not result
in fitness impacts to individuals;
The specified activity and ensonification area is very
small relative to the overall habitat ranges of California sea lions
and does not include habitat areas of special significance (e.g.,
biologically important areas); and
The presumed efficacy of the planned mitigation measures
in reducing the effects of the specified activity to the level of least
practicable adverse impact.
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 planned monitoring and
mitigation measures, NMFS finds that the total marine mammal take from
the planned activity will have a negligible impact on all affected
marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
The Marine Mammal Occurrence and Take Calculation and Estimation
section describes the number of California sea lions that could be
exposed to received noise levels that could cause Level B harassment
for the Navy's planned activities in the project area site relative to
the total stock abundance. Based on the estimated stock abundance
presented in the 2018 Final SARs (257,606), our analysis shows that
less than 1 percent of the affected stock could be taken by harassment.
Based on the analysis contained herein of the planned activity
(including the mitigation and monitoring measures) and the anticipated
take of marine mammals, NMFS finds that small numbers of marine mammals
will 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.
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 action with respect to environmental
[[Page 33139]]
consequences 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 determined that the issuance of the
IHA qualifies to be categorically excluded from further NEPA review.
Endangered Species Act (ESA)
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.
No incidental take of ESA-listed species is authorized 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.
Authorization
NMFS has issued an IHA to the Navy for the incidental take of
marine mammals due to in-water construction activities associated with
the Floating Dry Dock Project at Naval Base San Diego in San Diego,
California from September 15, 2020 to September 14, 2021, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated.
Dated: May 27, 2020.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2020-11732 Filed 5-29-20; 8:45 am]
BILLING CODE 3510-22-P