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, 33129-33139 [2020-11732]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[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
----------------------------------------------------------------------------------------------------------------
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.
----------------------------------------------------------------------------------------------------------------
\*\ 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