Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Pile Driving Training Exercises at Naval Base Ventura County, Port Hueneme, 15956-15980 [2023-05242]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 50 (Wednesday, March 15, 2023)]
[Notices]
[Pages 15956-15980]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-05242]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB988]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Pile Driving Training Exercises at 
Naval Base Ventura County, Port Hueneme

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from the United States Navy (Navy) 
for authorization to take marine mammals incidental to pile driving 
training exercises at Naval Base Ventura County, Port Hueneme (NBVC). 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-time, 1 year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorization and agency responses will be 
summarized in the final notice of our decision. The Navy's activities 
are considered (a) military readiness activities pursuant to the MMPA, 
as amended by the National Defense Authorization Act for Fiscal Year 
2004 (2004 NDAA).

DATES: Comments and information must be received no later than April 
14, 2023.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email to 
[email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at 
www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities without change. All 
personal identifying information (e.g., name, address) voluntarily 
submitted by the commenter may be publicly accessible. Do not submit 
confidential business information or otherwise sensitive or protected 
information.

FOR FURTHER INFORMATION CONTACT: Reny Tyson Moore, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-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

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intentional, taking of small numbers of marine mammals by U.S. citizens 
who engage in a specified activity (other than commercial fishing) 
within a specified geographical region if certain findings are made and 
either regulations are proposed or, if the taking is limited to 
harassment, a notice of a proposed incidental harassment authorization 
is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on 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 2004 NDAA (Pub. L. 108-136) removed the ``small numbers'' and 
``specified geographical region'' limitations indicated above and 
amended the definition of ``harassment'' as applied to a ``military 
readiness activity.'' The NDAA also amended the process as it relates 
to military readiness activities and the incidental take authorization 
process such that ``least practicable impact'' on such species or stock 
shall include consideration of personnel safety, practicality of 
implementation, and impact on the effectiveness of the military 
readiness activity. Before making the required determination, the 
Secretary shall consult with the Department of Defense regarding 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity. The activity for 
which incidental take of marine mammals is being requested addressed 
here qualifies as a military readiness activity. The definitions of all 
applicable MMPA statutory terms cited above are included in the 
relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment. This action 
is consistent with categories of activities identified in Categorical 
Exclusion B4 (IHAs with no anticipated serious injury or mortality) of 
the Companion Manual for NOAA Administrative Order 216-6A, which do not 
individually or cumulatively have the potential for significant impacts 
on the quality of the human environment and for which we have not 
identified any extraordinary circumstances that would preclude this 
categorical exclusion. Accordingly, NMFS has preliminarily determined 
that the issuance of the proposed IHA qualifies to be categorically 
excluded from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    NMFS received a request from the U.S. Navy on August 18, 2021, for 
an IHA to take marine mammals incidental to pile driving training 
exercises at NBVC. NMFS provided comments on the application and the 
Navy resubmitted a revised application on May 11, 2022. On May 25, 
2022, the Navy notified NMFS of the need to update the application to 
include additional activities. NMFS received the updated application on 
October 26, 2022. NMFS provided comments on the updated application and 
received a revised application from the Navy on December 5, 2022. NMFS 
provided additional comments on the application on December 8, 2022, 
and received an update application on January 6, 2023, which was deemed 
adequate and complete on January 12, 2023. The Navy's request is for 
take of California sea lions (Zalophus californius) and harbor seals 
(Phoca vitulina richardii) by Level B harassment only. Neither the Navy 
nor NMFS expect serious injury or mortality to result from this 
activity and, therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    The primary mission of NBVC is to provide a home port and to 
furnish training, administrative, and logistical support for the Naval 
Construction Battalions. Naval Construction Group ONE (NCG-1) is 
proposing to execute pile driving training exercises at NBVC that are 
essential to construction battalion personnel prior to deployment. The 
proposed work would include vibratory and impact pile driving, 
temporary pier construction, and subsequent removal of all installed 
materials. Training would occur at either Wharf 4 or Wharf D. These are 
military readiness activities, as defined under the National 7 Defense 
Authorization Act (NDAA) of Fiscal Year 2004 (Pub. L. 108-136).
    Up to four training exercises would take place during the proposed 
authorization period. Each training exercise would last up to 24 days 
and would include pile installation and removal of a sheet pile wall 
and round pile pier. The sheet pile wall and pier construction/removal 
would occur during the same training evolution, but would not occur at 
the same time. The U.S. Navy is requesting an IHA for Level B 
harassment of California sea lions and harbor seals related to these 
activities. Level A harassment is not anticipated or requested. The IHA 
would be valid for one year after issuance.

Dates and Duration

    The total annual days of active in-water pile installation and 
removal would be 96 days. These days would be spread over four annual 
training exercises, each of which would include 12 days for in-water 
pile installation and 12 days for in-water pile removal (i.e., each 
training exercise would last 24 days). Each workday would occur during 
daylight hours, and would last approximately eight hours, but pile 
driving/removal would not occur for the entire eight hours. Due to the 
availability of resources, requirements by NBVC for port use, and 
battalion training needs, it is not possible to predict the precise 
dates of training activities; however, no more than four separate 
training events would occur over the duration of the proposed 1 year 
IHA.

Geographic Region

    Port Hueneme is located approximately 102 kilometers (km) (55 
nautical miles) northeast of Los Angeles. The port is adjacent to the 
Santa Barbara Channel, between the California coast and the offshore 
Channel Islands. Port Hueneme does not fall within the Study Area for 
any other Navy at-sea Environmental Impact Statements/Overseas 
Environmental Impact Statements in the region, as it is also north of 
the Navy's Hawaii-Southern California Training and Testing (HSTT) Study 
Area, and east of the Navy's Point Mugu Sea Range Study Area.
    Port Hueneme Harbor encompasses NBVC Port Hueneme and a commercial 
port. The entrance channel is 2,300 ft (701 m) long with the narrowest 
width of the channel entrance at 330 ft (101 m). The average depth of 
the harbor is 34.5 ft (10.5 m) at Mean Lower Low Water. Port operations 
comprise

[[Page 15958]]

approximately 200 acres at the southern end of NBVC Port Hueneme. The 
substrate is primarily mud, with occasional rock debris at the base of 
the inlet jetties. Marine subtidal habitat at NBVC Port Hueneme 
consists of communities associated with sand, mud, and rock substrates. 
Shoreline features in the harbor around Wharf 4 and Wharf D include 
riprap, quay walls, and wharf pilings.
    Each training event would occur at either Wharf 4 or Wharf D at 
NBVC. Wharf 4 contains two potential pile driving sites. The Wharf 4 
South site is located directly in front of the Naval Facilities 
Engineering and Expeditionary Warfare Center Dive Locker, while the 
Wharf 4 East site is located along the side of the Naval Facilities 
Engineering and Expeditionary Warfare Center Dive Locker (Figure 1). 
The Wharf D site is located near the mouth of the harbor (Figure 2). 
The Wharf 4 locations are open to the majority of the harbor, whereas 
the Wharf D location is almost entirely self-contained, with only one 
access point from the channel leading to the harbor itself. No part of 
the proposed training exercises would occur outside of Port Hueneme 
Harbor in the Pacific Ocean.
BILLING CODE 3510-22-P

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[GRAPHIC] [TIFF OMITTED] TN15MR23.000


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[GRAPHIC] [TIFF OMITTED] TN15MR23.001

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    The specific components of each exercise may vary based on the 
specific training requirements for each battalion, but could include 
steel sheet pile driving and round pile driving. Therefore, the 
proposed action laid out herein is based on the components that would 
result in the most piles being driven through the duration of the 
exercise. For all pile driving efforts, a 50-ton crane would be placed 
on either the southernmost or easternmost end of Wharf 4, or along the 
western wall of Wharf D, and would be used for both installation and 
removal of the piles. Impact pile driving would use a DELMAG D12-32 (or 
similar) diesel hammer, while vibratory pile driving would use a 
vibratory hammer. Various

[[Page 15961]]

moveable floats, or potentially a small boat, would be used to provide 
in-, or near,-water support for the pile installation and/or removal. 
Only one hammer would be used at any given point in time; there would 
not be any instances where multiple piles would be driven 
simultaneously. All piles would be removed using a vibratory hammer.

Steel Sheet Pile Driving

    The sheet pile wall would be constructed in one of two ways: either 
as a continuous wall or as a set of up six sheet piles repeatedly 
driven in the same location to reach a certain number of piles in a 
smaller space. In this case, up to six piles would be driven, then all 
but one removed before the process would begin again.
    Steel sheet piles are ``Z'' shaped and made of corrugated steel. 
Each sheet pile would be 24-inches wide, \3/4\-inch thick and with a 
height of 16.14 inches. The total footprint of the disturbed area due 
to each sheet pile would be approximately 2.7 square feet (ft) (0.25 
square meters (m)). Once the first sheet pile is driven, each 
subsequent sheet pile would be interlocked with the pile next to it. 
The crane would slide a pile into the locking channel of the adjacent 
pile, then into the water. Once the undriven pile is stable, the crane 
would release the pile, swing the vibratory hammer over and attach it 
to the pile. Vibratory pile driving would be the only means of driving 
sheet piles. Each pile would be driven to a depth of approximately 30 
ft (9 meters (m)) into the seafloor. Installation of each sheet pile 
would take approximately 1.5 hours to complete, with up to ten minutes 
of driving during that timeframe. Removal of each sheet pile would take 
approximately 20 minutes.
    Three sheet piles would typically be driven into place during each 
operating day. Each workday is anticipated to last approximately eight 
hours, which would include pile driving and supporting pierside 
activities. Up to 5 days of steel sheet pile installation and 5 days of 
steel sheet removal would occur per training exercise.
    Two 14-inch steel H-beam piles would be driven per exercise in 
order to support templates for placing steel sheets. These H-beam piles 
would typically be driven using a vibratory hammer, but there is 
potential that they could be driven via impact hammer. Installation and 
removal of the two H-beam piles would take one day, respectively. This 
exercise is summarized in Table 1.

                            Table 1--Summary of Pile Details and Estimated Effort Required for Pile Installation and Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Vibratory                       Production rate (piles/day)
                                                          installation/      Potential   --------------------------------
                                 Size       Number of        removal      impact strikes                                      Days of         Days of
       Pile type/shape         (inches)   sheets/piles     duration per    per pile, if                                    installation       removal
                                                            pile/sheet        needed       Installation       Removal
                                                            (minutes)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steel Sheet.................         24              15  10/20..........              NA               3               3               5               5
Timber Pile.................         16              10  20/30..........           1,800               2               2               5               5
H-Beam......................         14               4  20/30..........           1,800               2               2               2               2
                             ---------------------------------------------------------------------------------------------------------------------------
    Project Totals..........  .........              29  7.17 hours/12    ..............  ..............  ..............              12              12
                                                          hours.
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Round Pile Driving

    Round timber piles would also be driven using either vibratory or 
impact pile driving methods. The Navy anticipates that installation and 
removal of round piles would take 5 days, respectively. Additional 
details regarding installation and removal rates are included in Table 
1.
    An example of the type of training exercise using round timber 
piles is the construction of a round pile pier. The constructed round 
pile pier would consist of up to ten, but typically six, 16-inch round 
pier piles spaced approximately 13 ft (4 m) apart and a pre-fabricated 
pier affixed to the piles above the waterline. After completion of site 
feasibility and a survey to ensure no obstructions at the seafloor, a 
guide system would be put in place (approximately 10 to 15 ft [3 to 4.5 
m] into the seafloor) in order to ensure piles are driven in the 
correct location and straight into the seafloor. The guide system would 
minimize the movement of a pile once the driving has commenced, and 
would utilize two steel H-beam piles to hold a template place. The 
piles would be lifted into place using the crane and the pile driver 
would be used to embed each pile to a depth of 30 to 35 ft (9 to 11 m) 
into the seafloor. It is expected that each timber pile would take 
approximately four hours to be installed into the seafloor, and that 
two piles per day would be installed; therefore, each day of pile 
installation would last for eight hours. Active pile installation time 
for each pile would be approximately 20 minutes. H-beam piles would 
typically be driven using a vibratory hammer, but there is potential 
that they could be driven via impact hammer. Installation of each H-
beam pile is anticipated to take 20 minutes, and up to two H-beam piles 
would be installed in one day. This exercise is summarized in Table 1.
    Once the pile driving is complete, the guide system (i.e., the H-
beam piles) would be removed and the U.S. Naval Mobile Construction 
Battalion personnel (known as Seabees) would build the decking system 
pier-side on Wharf 4 or Wharf D. The decking system would then be 
lifted by the crane onto the round piles, and the Seabees would secure 
the deck to the piles. At this point, the pier installation would be 
complete, and the decking would be detached from the piles and lifted 
back to land by the crane. The piles would be removed from the sediment 
one-by-one with the vibratory hammer and placed onto the wharf. The 
Navy anticipates each timber pile would take approximately 30 minutes 
to remove via a vibratory hammer and that up to 2 timber piles would be 
removed each day. They further anticipate that each H-beam pile would 
take approximately 30 minutes to remove via a vibratory hammer and that 
up to 2 H-beam piles would be removed each day.
    All piles used for this exercise would be washed thoroughly at the 
NBVC Wash Rack area, which is a self-contained system that ensures the 
runoff from pile washing would have no environmental impact. The piles 
would be staged at the NCG-1 staging yard.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, incorporated here by reference, instead of 
reprinting the information. Additional information regarding

[[Page 15962]]

population trends and threats may be found in NMFS' Stock Assessment 
Reports (SARs; 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 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this action, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS' 
SARs). While no serious injury or mortality is 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 SARs (e.g., Carretta et al., 2022). All values 
presented in Table 2 are the most recent available at the time of 
publication and are available in the 2021 SARs (Carretta et al., 2022) 
(available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                                              Table 2--Species Likely Impacted by the Specified Activities
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                                                                                                            Stock abundance Nbest,
                                                                                          ESA/MMPA status;  (CV, Nmin, most recent             Annual M/
             Common name                  Scientific name             MMPA stock          strategic (Y/N)    abundance survey) \2\     PBR       SI \3\
                                                                                                \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    California sea lion.............  Zalophus californianus  U.S......................  -,-, N             257,606 (N.A.;             14,011       >320
                                                                                                             233,515; 2014).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina          California...............  -,-, N             30,968 (N.A.; 27,348;       1,641         43
                                       richardii.                                                            2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 (N.A.).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.

    As indicated above, the 2 species (with 2 managed stocks) in Table 
2 temporally and spatially co-occur with the activity to the degree 
that take is reasonably likely to occur.

California Sea Lion

    California sea lions occur in the eastern North Pacific from Puerto 
Vallarta, Mexico, through the Gulf of California and north along the 
west coast of North America to the Gulf of Alaska (Jefferson et al., 
2015; Maniscalco et al., 2004). International agreements between the 
U.S., Mexico, and Canada for joint management of California sea lions 
do not exist; therefore, California sea lions observed at rookeries 
north of the U.S./Mexico border are considered part of the U.S. stock. 
California sea lions are the most abundant pinniped found along the 
California coast.
    During the summer, California sea lions typically congregate near 
rookery islands and specific open-water areas. The primary rookeries 
off the coast of the U.S. are on San Nicolas, San Miguel, Santa 
Barbara, and San Clemente Islands (Lowry et al., 2008; Lowry and 
Forney, 2005; Lowry et al., 2017). Sea lions breed on the offshore 
islands of southern and central California from May through July (Heath 
and Perrin, 2009). During the non-breeding season, adult and subadult 
males and juveniles migrate northward along the coast to central and 
northern California, Oregon, Washington, and Vancouver Island 
(Jefferson et al., 1993). They return south the following spring (Heath 
and Perrin, 2008, Lowry and Forney, 2005). Females and some juveniles 
tend to remain closer to rookeries (Antonelis et al., 1990; Melin et 
al., 2008). Pupping occurs primarily on the California Channel Islands 
from late May until the end of June (Peterson and Bartholomew, 1967). 
Weaning and mating occur in late spring and summer during the peak 
upwelling period (Bograd et al., 2009). After the mating season, adult 
males migrate northward to feeding areas as far away as the Gulf of 
Alaska (Lowry et al., 1992), and they remain away until spring (March-
May), when they migrate back to the breeding colonies. Adult females 
generally remain south of Monterey Bay, California throughout the year, 
feeding in coastal waters in the summer and offshore waters in the 
winter, alternating between foraging and nursing their pups on shore 
until the next pupping/breeding season (Melin and DeLong, 2000; Melin 
et al., 2008).
    California sea lions are known to feed in both benthic and open-
water habitats, and have a broad diet range, feeding on a variety of 
fish and cephalopod species depending on the environment. Common prey 
items include salmon, Pacific sardines (Sardinops sagax), northern 
anchovy (Engraulis mordax), mackerel, Pacific whiting (Merluccius 
productus), rockfish, market squid (Loligo opalescens), bass, 
cutlassfish, cusk eels, greenlings, dogfish, perch, and various 
flatfish (Lowry and Forney, 2005; Orr et al., 2011,; Orr et al., 2012), 
midshipmen and lanternfish (Lowry and Forney, 2005; Orr et al., 2011; 
Orr et al., 2012). Dive durations range from 1.4 to 5 minutes, with 
longer dives during El Ni[ntilde]o events; sea lions dive about 32 to

[[Page 15963]]

47 percent of the time at sea (Feldkamp et al., 1989; Kuhn and Costa, 
2014; Melin and DeLong, 2000; Melin et al., 2008). Adult females 
alternate between nursing their pup on shore and foraging at sea, 
spending approximately 67 to 77 percent of time at sea (Kuhn and Costa, 
2014; Melin and DeLong, 2000).
    From January 2013 through September 2016, a greater than expected 
number of young malnourished California sea lions stranded along the 
coast of California. This event was classified as an unusual mortality 
event (UME) as defined under Section 410(6) of the MMPA as it was a 
stranding that was unexpected; involved a significant die-off of a 
marine mammal population, and demanded immediate response. Sea lions 
stranding from an early age (6-8 months old) through two years of age 
(hereafter referred to as juveniles) were consistently underweight 
without other disease processes detected. Of the 8,122 stranded 
juveniles attributed to the UME, 93 percent stranded alive (n = 7,587, 
with 3,418 of these released after rehabilitation) and 7 percent (n = 
531) stranded dead. Several factors are hypothesized to have impacted 
the ability of nursing females and young sea lions to acquire adequate 
nutrition for successful pup rearing and juvenile growth. In late 2012, 
decreased anchovy and sardine recruitment (CalCOFI data, July 2013) may 
have led to nutritionally stressed adult females. Biotoxins were 
present at various times throughout the UME, and while they were not 
detected in the stranded juvenile sea lions (whose stomachs were empty 
at the time of stranding), biotoxins may have impacted the adult 
females' ability to support their dependent pups by affecting their 
cognitive function (e.g., navigation, behavior towards their 
offspring). Therefore, the role of biotoxins in this UME, via its 
possible impact on adult females' ability to support their pups, is 
unclear. The proposed primary cause of the UME was malnutrition of sea 
lion pups and yearlings due to ecological factors. These factors 
included shifts in distribution, abundance and/or quality of sea lion 
prey items around the Channel Island rookeries during critical sea lion 
life history events (nursing by adult females, and transitioning from 
milk to prey by young sea lions). These prey shifts were most likely 
driven by unusual oceanographic conditions at the time due to the event 
known as the ``Warm Water Blob'' and El Ni[ntilde]o. This investigation 
closed on May 6, 2020. Please refer to: https://www.fisheries.noaa.gov/national/marine-life-distress/2013-2016-california-sea-lion-unusual-mortality-event-california for more information on this UME.
    California sea lions in the U.S. are not listed as ``endangered'' 
or ``threatened'' under the ESA or as ``depleted'' under the MMPA. They 
are also not considered ``strategic'' under the MMPA because human-
caused mortality is less than the PBR. The fishery mortality and 
serious injury rate (197 animals/year) for this stock is less than 10 
percent of the calculated PBR and, therefore, is considered to be 
insignificant and approaching a zero mortality and serious injury rate 
(Laake et al., 2018). Expanding pinniped populations though have 
resulted in increased human-caused serious injury and mortality, due to 
shootings, entrainment in power plants, interactions with hook and line 
fisheries, separation of mothers and pups due to human disturbance, dog 
bites, and vessel and vehicle strikes (Carretta et al., 2021). Other 
threats to California sea lions include exposure to anthropogenic 
sound, algal neurotoxins, and increasing sea-surface temperatures in 
the California Current (Carretta et al., 2021).
    California sea lions are prone to invade human-modified coastal 
sites that provide good hauling out substrate, such as marina docks and 
floats, buoys, bait barges, small boats, and rip-rap tidal and wave 
protection structures. They are known to be present on these structures 
within the proposed action area, occasionally in large numbers. The 
primary sea lion haulout at NBVC is on and around the floating docks at 
Wharf D, though other areas are occasionally used. California sea lions 
were also frequently encountered swimming near the channel markers, and 
their presence within the proposed action area is considered 
``regular'' according to the NBVC Integrated Natural Resources 
Management Plan (Department of the Navy, 2019).

Harbor Seal

    Harbor seals are widely distributed in the North Atlantic and North 
Pacific. Two subspecies exist in the Pacific: P. v. stejnegeri in the 
western North Pacific, near Japan, and P. v. richardii in the eastern 
North Pacific (Burns, 2002; Jefferson et al., 2008). Of the two 
subspecies, only the eastern North Pacific subspecies would be found in 
the proposed action area. This subspecies inhabits near-shore coastal 
and estuarine areas from Baja California, Mexico, to the Pribilof 
Islands in Alaska. Previous assessments of the status of harbor seals 
have recognized three stocks along the west coast of the continental 
U.S.: (1) California, (2) Oregon and Washington outer coast waters, and 
(3) inland waters of Washington (Carretta et al., 2022). Harbor seals 
observed in the proposed action area are considered members of the 
California stock.
    Harbor seals are rarely found more than 20 km (11 nautical miles) 
from shore (Baird, 2001) and are generally non-migratory (Burns, 2002; 
Jefferson et al., 2008) and solitary at sea, with local movements 
associated with such factors as tides, weather, season, food 
availability, and reproduction (Bigg, 1969, 1981; Boveng et al., 2012; 
Fisher, 1952; Hastings et al., 2004; Lowry et al,. 2001; Rehberg and 
Small, 2001; Scheffer and Slipp, 1944; Small et al,. 2005; Small et 
al., 2003; Swain et al., 1996). While primarily aquatic, harbor seals 
also use the coastal terrestrial environment, where they haul out of 
the water periodically on to rocks, reefs, beaches, and anthropogenic 
structures to regulate their body temperature, molt, interact with 
other seals, give birth, and raise their pups. Pupping occurs from 
March through May in central California (Codde and Allen, 2020). Pups 
are weaned in four weeks, most by mid-June (Codde and Allen, 2020). 
Harbor seals breed between late March and June. Harbor seals molt from 
May through June. Peak numbers of harbor seals haul out during late May 
to July, which coincides with the peak molt. During both pupping and 
molting seasons, the number of seals and the length of time hauled out 
per day increase, from an average of 7 hours per day to 10-12 hours 
(Harvey and Goley, 2011; Huber et al., 2001; Stewart and Yochem, 1994). 
They haul out in groups to avoid predators, with groups spending less 
time being watchful for predators than individuals that haul out alone.
    Harbor seals feed in marine, estuarine, and occasionally fresh 
water environments. They tend to forage at night and haul out during 
the day with a peak in the afternoon between 1 p.m. and 4 p.m. (Grigg 
et al., 2012; Stewart and Yochem, 1994; Yochem et al., 1987). Tide 
levels affect the maximum number of seals hauled out, with the largest 
number of seals hauled out at low tide, but time of day and season have 
the greatest influence on haul out behavior (Manugian et al., 2017; 
Patterson and Acevedo-Guti[eacute]rrez, 2008; Stewart and Yochem, 
1994).
    Diving behavior analyses of harbor seals in shallow estuarine 
environments indicated that they spent more than 80 percent of their 
time diving in the upper portion of the water column at or above 185 ft 
(56 m), but exhibited relatively long duration dives (4.4 to 5.2 
minutes) (Eguchi, 1998; Womble et al. 2014).

[[Page 15964]]

Since the proposed action area is very shallow, with an average depth 
of 34.5 ft (10.5 m) at mean low water, it is likely that harbor seals, 
when present, would always be at or near the surface (Tetra Tech, 
2012).
    California harbor seals are not listed as ``endangered'' or 
``threatened'' under the ESA, nor are they designated as ``depleted'' 
under the MMPA. Annual human-caused mortality does not exceed Potential 
Biological Removal (PBR) threshold for this stock, and they are not 
considered a ``strategic'' stock under the MMPA (Carretta et al., 
2022). Despite this, expanding pinniped populations in general have 
resulted in increased human-caused serious injury and mortality, due to 
shootings, entrainment in power plants, interactions with recreational 
hook and line fisheries, separation of mothers and pups due to human 
disturbance, dog bites, and vessel and vehicle strikes (Carretta et al. 
2022).
    Small numbers of harbor seals are found hauled out on coastal and 
island sites and forage in the nearshore waters of Southern California, 
but are found in only moderate numbers compared to sea lions and 
elephant seals. In California, approximately 400-600 harbor seal 
haulout sites are widely distributed along the mainland and on offshore 
islands, including intertidal sandbars, rocky shores and beaches 
(Hanan, 1996; Lowry et al., 2008). The harbor seal haul-out sites 
include several areas along the coast of La Jolla in San Diego County 
and most of the Channel Islands (Lowry et al., 2008; Lowry et al., 
2017). Harbor seals have been reported hauling out on the beach just 
outside the mouth of Port Hueneme Harbor, but the Integrated Natural 
Resources Management Plan for NBVC categorizes their presence on the 
beach as ``rare'' (Department of the Navy, 2019). Pacific harbor seals 
are also considered rare in Port Hueneme and no harbor seal haul-outs 
are present in the action area.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 3.

                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a discussion of the ways that components of 
the specified activity may impact marine mammals and their habitat. The 
Estimated Take section later in this document includes a quantitative 
analysis of the number of individuals that are expected to be taken by 
this activity. The Negligible Impact Analysis and Determination section 
considers the content of this section, the Estimated Take section, and 
the Proposed Mitigation section, to draw conclusions regarding the 
likely impacts of these activities on the reproductive success or 
survivorship of individuals and how those impacts are reasonably 
expected to, or reasonably likely to, adversely affect the species or 
stock through effects on annual rates of recruitment or survival.
    Acoustic effects on marine mammals during the specified activity 
can occur from impact and vibratory pile driving. The effects of 
underwater noise from the Navy's proposed activities have the potential 
to result in Level B harassment of marine mammals in the action area.

Description of Sound Sources

    This section contains a brief technical background on sound, on the 
characteristics of certain sound types, and on metrics used in this 
proposal inasmuch as the information is relevant to the specified 
activity and to a discussion of the potential effects of the specified 
activity on marine mammals found later in this document. For general 
information on sound and its interaction with the marine environment, 
please see, e.g., Au and Hastings (2008); Richardson et al. (1995); 
Urick (1983).
    Sound travels in waves, the basic components of which are 
frequency, wavelength, and amplitude. Frequency

[[Page 15965]]

is the number of pressure waves that pass by a reference point per unit 
of time and is measured in hertz (Hz) or cycles per second. Wavelength 
is the distance between two peaks or corresponding points of a sound 
wave (length of one cycle). Higher frequency sounds have shorter 
wavelengths than lower frequency sounds, and typically attenuate 
(decrease) more rapidly, except in certain cases in shallower water. 
Amplitude is the height of the sound pressure wave or the ``loudness'' 
of a sound and is typically described using the relative unit of the 
dB. A sound pressure level (SPL) in dB is described as the ratio 
between a measured pressure and a reference pressure (for underwater 
sound, this is 1 microPascal ([mu]Pa)), and is a logarithmic unit that 
accounts for large variations in amplitude; therefore, a relatively 
small change in dB corresponds to large changes in sound pressure. The 
source level represents the SPL referenced at a distance of 1 m from 
the source (referenced to 1 [mu]Pa), while the received level is the 
SPL at the listener's position (referenced to 1 [mu]Pa). The received 
level is the sound level at the listener's position. Note that all 
underwater sound levels in this document are referenced to a pressure 
of 1 [mu]Pa and all airborne sound levels in this document are 
referenced to a pressure of 20 [mu]Pa.
    Root mean square (RMS) is the quadratic mean sound pressure over 
the duration of an impulse. RMS is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick, 1983). RMS accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper, 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    Sound exposure level (SEL; represented as dB referenced to 1 [mu]Pa 
squared per second (re 1 [mu]Pa2-s)) represents the total energy in a 
stated frequency band over a stated time interval or event, and 
considers both intensity and duration of exposure. The per-pulse SEL is 
calculated over the time window containing the entire pulse (i.e., 100 
percent of the acoustic energy). SEL is a cumulative metric; it can be 
accumulated over a single pulse, or calculated over periods containing 
multiple pulses. Cumulative SEL (SELcum) represents the total energy 
accumulated by a receiver over a defined time window or during an 
event. Peak sound pressure (also referred to as zero-to-peak sound 
pressure or 0-pk) is the maximum instantaneous sound pressure 
measurable in the water at a specified distance from the source, and is 
represented in the same units as the RMS sound pressure.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in a 
manner similar to ripples on the surface of a pond and may be either 
directed in a beam or beams or may radiate in all directions 
(omnidirectional sources), as is the case for sound produced by the 
construction activities considered here. The compressions and 
decompressions associated with sound waves are detected as changes in 
pressure by aquatic life and man-made sound receptors such as 
hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound, which is 
defined as the all-encompassing sound in a given place and is usually a 
composite of sound from many sources both near and far (American 
National Standards Institute standards (ANSI), 1995). The sound level 
of a region is defined by the total acoustical energy being generated 
by known and unknown sources. These sources may include physical (e.g., 
wind and waves, earthquakes, ice, atmospheric sound), biological (e.g., 
sounds produced by marine mammals, fish, and invertebrates), and 
anthropogenic (e.g., vessels, dredging, construction) sound. A number 
of sources contribute to ambient sound, including wind and waves, which 
are a main source of naturally occurring ambient sound for frequencies 
between 200 Hz and 50 kilohertz (kHz) (Mitson, 1995). In general, 
ambient sound levels tend to increase with increasing wind speed and 
wave height. Precipitation can become an important component of total 
sound at frequencies above 500 Hz, and possibly down to 100 Hz during 
quiet times. Marine mammals can contribute significantly to ambient 
sound levels, as can some fish and snapping shrimp. The frequency band 
for biological contributions is from approximately 12 Hz to over 100 
kHz. Sources of ambient sound related to human activity include 
transportation (surface vessels), dredging and construction, oil and 
gas drilling and production, geophysical surveys, sonar, and 
explosions. Vessel noise typically dominates the total ambient sound 
for frequencies between 20 and 300 Hz. In general, the frequencies of 
anthropogenic sounds are below 1 kHz and, if higher frequency sound 
levels are created, they attenuate rapidly.
    No direct data on ambient noise levels within Port Hueneme are 
available; however, in-water ambient noise levels are considered 
comparable to similar ports and harbors. McKenna et al. (2013) observed 
as many as 18 container ships per day transiting through or past Port 
Hueneme in the Santa Barbara Channel, with sound level per ship varying 
with vessel speed, but ranging from 175 to 195 dB re 1 [mu]Pa2 at 1 m 
with frequencies ranging from 20 to 1,000 Hz. Though this is outside 
the proposed action area, it illustrates the high vessel volume in the 
region. Similarly, Kipple and Gabriel (2004) found that ship noise was 
characterized by a broad frequency range (roughly 0.1 to 35 kHz), with 
peak noise at higher frequency for smaller vessels. Similar broad-
spectrum (10 Hz to more than 1 kHz) noise has been reported for a 
variety of categories of ships (National Research Council, 2003). Port 
Hueneme Harbor is co-owned by NBVC, Port Hueneme, and the Oxnard Harbor 
District, and the commercial port sees 8 billion dollars annually in 
goods movement, with multiple berths for large cargo ships (Port of 
Hueneme, 2019). Maintenance of the port for accommodation of those 
large cargo ships includes dredging, which also increases the 
soundscape underwater.
    Ambient noise levels in ports and harbors vary by location, but 
generally exceed the Level B harassment threshold for continuous noise 
of 120 dB RMS in heavily trafficked locations. For example, from 2014 
to 2015, ambient noise data was collected in the northern portion of 
the San Diego Bay during ten separate deployments of 3 days each. 
During those deployments, ambient noise levels ranged from 126 to 146 
dB RMS, with typical ambient levels around 129 to 130 dB RMS (Naval 
Facilities Engineering Command Southwest; NAVFAC SW, 2020). More recent 
ambient data collected in the south-central San Diego Bay (an area with 
less vessel traffic than the north San Diego Bay), showed ambient SPLs 
ranging from 121 to 131 dB RMS, and an average ambient SPL at 126 dB 
RMS (Dahl and Dall'Osto, 2019). Similar ports with large container ship 
transits also had ambient levels that were higher than the regulatory 
120 dB RMS threshold, with ambient SPLs at different locations in Puget 
Sound measured at 128 dB RMS (Washington State Department of 
Transportation,

[[Page 15966]]

2012) and between 132 and 143 dB RMS (Strategic Environmental 
Consulting, 2005), while in San Francisco Bay ambient SPLs were 
measured at 133 dB RMS (Laughlin, 2006).
    While no ambient data is available for the specific proposed 
project area, it is assumed that, due to both the Navy's and commercial 
use of Port Hueneme, ambient SPLs will be higher than the 120 dB RMS 
regulatory threshold for continuous noise. However, absent specific 
values for the project location, all acoustical analyses for continuous 
noise sources (i.e., vibratory pile driving) will be assessed relative 
to the 120 dB RMS Level B harassment threshold.
    Two types of hammers would be used on this project: impact and 
vibratory. The sounds produced by these hammers fall into one of two 
general sound types: impulsive and non-impulsive (defined below). The 
distinction between these two sound types is important because they 
have differing potential to cause physical effects, particularly with 
regard to hearing (e.g., Ward, 1997 in Southall et al., 2007). Please 
see Southall et al. (2007) for an in-depth discussion of these 
concepts.
    Impulsive sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986; Harris, 1998; National Institute for Occupational Safety 
and Health (NIOSH), 1998; International Organization for 
Standardization (ISO) 2003; ANSI 2005) and occur either as isolated 
events or repeated in some succession. Impulsive sounds are all 
characterized by a relatively rapid rise from ambient pressure to a 
maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-impulsive sounds can be tonal, narrowband, or broadband, brief 
or prolonged, and may be either continuous or non-continuous (ANSI, 
1995; NIOSH, 1998). Some of these non-impulsive sounds can be transient 
signals of short duration but without the essential properties of 
impulses (e.g., rapid rise time). Examples of non-impulsive sounds 
include those produced by vessels, aircraft, machinery operations such 
as drilling or dredging, vibratory pile driving, and active sonar 
systems. The duration of such sounds, as received at a distance, can be 
greatly extended in a highly reverberant environment.
    Impact hammers operate by repeatedly dropping and/or pushing a 
heavy piston onto a pile to drive the pile into the substrate. Sound 
generated by impact hammers is characterized by rapid rise times and 
high peak levels, a potentially injurious combination (Hastings and 
Popper, 2005). Vibratory hammers install piles by vibrating them and 
allowing the weight of the hammer to push them into the sediment. 
Vibratory hammers produce significantly less sound than impact hammers. 
Peak Sound Pressure Levels (SPLs) may be 180 dB or greater, but are 
generally 10 to 20 dB lower than SPLs generated during impact pile 
driving of the same-sized pile (Oestman et al., 2009). Rise time is 
slower, reducing the probability and severity of injury, and sound 
energy is distributed over a greater amount of time (Nedwell and 
Edwards, 2002; Carlson et al., 2005).
    The likely or possible impacts of the Navy's proposed activity on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of the equipment and personnel; however, any impacts to marine 
mammals are expected to primarily be acoustic in nature. Acoustic 
stressors include effects of heavy equipment operation during pile 
installation and removal.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal is the primary means by which 
marine mammals may be harassed from the Navy's specified activity. In 
general, animals exposed to natural or anthropogenic sound may 
experience physical and psychological effects, ranging in magnitude 
from none to severe (Southall et al., 2007; 2019). In general, exposure 
to pile driving noise has the potential to result in auditory threshold 
shifts and behavioral reactions (e.g., avoidance, temporary cessation 
of foraging and vocalizing, changes in dive behavior). Exposure to 
anthropogenic noise can also lead to non-observable physiological 
responses such an increase in stress hormones. Additional noise in a 
marine mammal's habitat can mask acoustic cues used by marine mammals 
to carry out daily functions such as communication and predator and 
prey detection. The effects of pile driving noise on marine mammals are 
dependent on several factors, including, but not limited to, sound type 
(e.g., impulsive vs. non-impulsive), the species, age and sex class 
(e.g., adult male vs. mom with calf), duration of exposure, the 
distance between the pile and the animal, received levels, behavior at 
time of exposure, and previous history with exposure (Wartzok et al., 
2004; Southall et al., 2007, Ellison et al., 2012, and Southall et al., 
2021). Here we discuss physical auditory effects (threshold shifts) 
followed by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral). When analyzing the auditory effects of noise exposure, it is 
often helpful to broadly categorize sound as either impulsive or non-
impulsive. When considering auditory effects, vibratory pile driving is 
considered a non-impulsive source while impact pile is treated as an 
impulsive source.
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Available data 
from humans and other terrestrial mammals indicate that a 40 dB 
threshold shift approximates PTS onset (see Ward et al., 1958, 1959; 
Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; 
Henderson et al., 2008). PTS levels for marine mammals are estimates, 
as with the exception of a single study unintentionally inducing PTS in 
a harbor seal (Kastak et al., 2008), there are no empirical data 
measuring PTS in marine mammals largely due to the fact that, for 
various ethical reasons, experiments involving

[[Page 15967]]

anthropogenic noise exposure at levels inducing PTS are not typically 
pursued or authorized (NMFS, 2018).
    Temporary Threshold Shift (TTS)--A temporary, reversible increase 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2018). Based on data from cetacean TTS measurements (see 
Southall et al., 2007), a TTS of 6 dB is considered the minimum 
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et 
al., 2000; Finneran et al., 2000, 2002). As described in Finneran 
(2015), marine mammal studies have shown the amount of TTS increases 
with SELcum in an accelerating fashion: at low exposures with lower 
SELcum, the amount of TTS is typically small and the growth curves have 
shallow slopes. At exposures with higher SELcum, the growth curves 
become steeper and approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
masking, below). For example, a marine mammal may be able to readily 
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal 
is traveling through the open ocean, where ambient noise is lower and 
there are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts. We note that reduced hearing sensitivity as 
a simple function of aging has been observed in marine mammals, as well 
as humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, but such relationships are assumed to be similar to 
those in humans and other terrestrial mammals. PTS typically occurs at 
exposure levels at least several decibels above (a 40-dB threshold 
shift approximates PTS onset; e.g., Kryter et al., 1966; Miller, 1974) 
that inducing mild TTS (a 6-dB threshold shift approximates TTS onset; 
e.g., Southall et al., 2007). Based on data from terrestrial mammals, a 
precautionary assumption is that the PTS thresholds for impulsive 
sounds (such as impact pile driving pulses as received close to the 
source) are at least 6 dB higher than the TTS threshold on a peak-
pressure basis and PTS cumulative sound exposure level thresholds are 
15 to 20 dB higher than TTS cumulative sound exposure level thresholds 
(Southall et al., 2007). Given the higher level of sound or longer 
exposure duration necessary to cause PTS as compared with TTS, it is 
considerably less likely that PTS could occur.
    TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. 
Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and six species of pinnipeds (northern elephant seal 
(Mirounga angustirostris), harbor seal, ring seal (Pusa hispida), 
spotted seal (Phoca largha), bearded seal (Erignathus barbatus), and 
California sea lion) that were exposed to a limited number of sound 
sources (i.e., mostly tones and octave-band noise with limited number 
of exposure to impulsive sources such as seismic airguns or impact pile 
driving) in laboratory settings (Southall et al., 2019). No data are 
available on noise-induced hearing loss for mysticetes. For summaries 
of data on TTS in marine mammals or for further discussion of TTS onset 
thresholds, please see Southall et al., (2019), and NMFS (2018).
    Installing piles requires a combination of impact pile driving and 
vibratory pile driving. For the project, these activities will not 
occur at the same time and there will be pauses in activities producing 
the sound during each day. Given these pauses and that many marine 
mammals are likely moving through the project area and not remaining 
for extended periods of time, the potential for TTS declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal also has the potential to behaviorally disturb marine mammals. 
Behavioral disturbance may include a variety of effects, including 
subtle changes in behavior (e.g., minor or brief avoidance of an area 
or changes in vocalizations), more conspicuous changes in similar 
behavioral activities, and more sustained and/or potentially severe 
reactions, such as displacement from or abandonment of high-quality 
habitat. Disturbance may result in changing durations of surfacing and 
dives, changing direction and/or speed; reducing/increasing vocal 
activities; changing/cessation of certain behavioral activities (such 
as socializing or feeding); eliciting a visible startle response or 
aggressive behavior (such as tail/fin slapping or jaw clapping); 
avoidance of areas where sound sources are located. Pinnipeds may 
increase their haul out time, possibly to avoid in-water disturbance 
(Thorson and Reyff, 2006). Behavioral responses to sound are highly 
variable and context-specific and any reactions depend on numerous 
intrinsic and extrinsic factors (e.g., species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day), as well as the interplay between factors (e.g., 
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007; 
Weilgart, 2007; Archer et al., 2010, Ellison et al., 2019; Southall et 
al., 2021). Behavioral reactions can vary not only among individuals 
but also within an individual, depending on previous experience with a 
sound source, context, and numerous other factors (Ellison et al., 
2012), and can vary depending on characteristics associated with the 
sound source (e.g., whether it is moving or stationary, number of 
sources, distance from the source). In general, pinnipeds seem more 
tolerant of, or at least habituate more quickly to, potentially 
disturbing underwater sound than do cetaceans, and generally seem to be 
less responsive to exposure to industrial sound than most cetaceans. 
Please see Richardson et al. (1995), Nowacek et al. (2007), Southall et 
al. (2007), Gomez et al. (2015), Southall et al. (2019), and Southall 
et al. (2021) for a review of responses of marine mammals to 
anthropogenic sounds. Habituation can occur when an animal's response 
to a stimulus wanes with repeated exposure, usually in the absence of 
unpleasant associated events (Wartzok et al., 2003). Animals are most 
likely to habituate to sounds that are predictable and unvarying. It is 
important to note that habituation is appropriately considered as a 
``progressive reduction in response to stimuli that are perceived as 
neither aversive nor beneficial,'' rather than as, more generally, 
moderation in response to human disturbance (Bejder et al.,

[[Page 15968]]

2009). The opposite process is sensitization, when an unpleasant 
experience leads to subsequent responses, often in the form of 
avoidance, at a lower level of exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al., 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al,. 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
(Eubalaena glacialis) have been observed to shift the frequency content 
of their calls upward while reducing the rate of calling in areas of 
increased anthropogenic noise (Parks et al., 2007). In some cases, 
animals may cease sound production during production of aversive 
signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
(Eschrictius robustus) are known to change direction--deflecting from 
customary migratory paths--in order to avoid noise from seismic surveys 
(Malme et al., 1984). Avoidance may be short-term, with animals 
returning to the area once the noise has ceased (e.g., Bowles et al., 
1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey 
et al., 2007). Longer-term displacement is possible, however, which may 
lead to changes in abundance or distribution patterns of the affected 
species in the affected region if habituation to the presence of the 
sound does not occur (e.g., Blackwell et al., 2004; Bejder et al., 
2006; Teilmann et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996; Bowers et al., 2018). The result of a flight response 
could range from brief, temporary exertion and displacement from the 
area where the signal provokes flight to, in extreme cases, marine 
mammal strandings (Evans and England, 2001). However, it should be 
noted that response to a perceived predator does not necessarily invoke 
flight (Ford and Reeves, 2008), and whether individuals are solitary or 
in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause

[[Page 15969]]

population declines through reduction of fitness (e.g., decline in body 
condition) and subsequent reduction in reproductive success, survival, 
or both (e.g., Harrington and Veitch, 1992; Daan et al., 1996; Bradshaw 
et al., 1998). However, Ridgway et al. (2006) reported that increased 
vigilance in bottlenose dolphins exposed to sound over a 5 day period 
did not cause any sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003), however 
distress is an unlikely result of this project based on observations of 
marine mammals during previous, similar construction projects.
    Auditory Masking--Acoustic masking is when other noises such as 
from human sources interfere with animal detection of acoustic signals 
such as communication calls, echolocation sounds, and environmental 
sounds important to marine mammals. Since many marine mammals rely on 
sound to find prey, moderate social interactions, and facilitate mating 
(Tyack, 2008), noise from anthropogenic sound sources can interfere 
with these functions, but only if the noise spectrum overlaps with the 
hearing sensitivity of the marine mammal and the sounds being used 
(Southall et al., 2007; Clark et al., 2009; Hatch et al., 2012). 
Chronic exposure to excessive, though not high-intensity, noise could 
cause masking at particular frequencies for marine mammals that utilize 
sound for vital biological functions (Clark et al., 2009). The ability 
of a noise source to mask biologically important sounds depends on the 
characteristics of both the noise source and the signal of interest 
(e.g., signal-to-noise ratio, temporal variability, direction), in 
relation to each other and to an animal's hearing abilities (e.g., 
sensitivity, frequency range, critical ratios, frequency 
discrimination, directional discrimination, age or TTS hearing loss), 
and existing ambient noise and propagation conditions. It is important 
to distinguish TTS and PTS, which persist after the sound exposure, 
from masking, which occurs during the sound exposure. Because masking 
(without resulting in TS) is not associated with abnormal physiological 
function, but rather changes in behavioral patterns resulting from lost 
opportunities (e.g., communication, feeding), it is not considered a 
physiological effect, but rather a potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore, 2014). Masking can be tested 
directly in captive species (e.g., Erbe, 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).

[[Page 15970]]

    Marine mammals in Port Hueneme are continuously exposed to 
anthropogenic noise which may lead to some habituation, but is also a 
source of masking. Vocalization changes may result from a need to 
compete with an increase in background noise and include increasing the 
source level, modifying the frequency, increasing the call repetition 
rate of vocalizations, or ceasing to vocalize in the presence of 
increased noise (Hotchkin and Parks, 2013). Pinnipeds may be at risk 
for vocal masking.
    Masking is more likely to occur in the presence of broadband, 
relatively continuous noise sources. Energy distribution of pile 
driving covers a broad frequency spectrum, and sound from pile driving 
would be within the audible range of California sea lions and harbor 
seals present in the proposed action area. While some pile driving 
during Navy training activities may mask some acoustic signals that are 
relevant to the daily behavior of pinnipeds, the short-term duration 
and limited areas affected make it very unlikely that the fitness or 
survival of any individuals would be affected.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal that have the potential to cause behavioral harassment, 
depending on their distance from these activities. Airborne noise would 
primarily be an issue for pinnipeds that are swimming or hauled out 
near the project site within the range of noise levels elevated above 
the acoustic criteria. We recognize that pinnipeds in the water could 
be exposed to airborne sound that may result in behavioral harassment 
when looking with their heads above water. Most likely, airborne sound 
would cause behavioral responses similar to those discussed above in 
relation to underwater sound. For instance, anthropogenic sound could 
cause hauled-out pinnipeds to exhibit changes in their normal behavior, 
such as reduction in vocalizations, or cause them to temporarily 
abandon the area and move further from the source. However, these 
animals would previously have been `taken' because of exposure to 
underwater sound above the behavioral harassment thresholds, which are 
in all cases larger than those associated with airborne sound. Thus, 
the behavioral harassment of these animals is already accounted for in 
these estimates of potential take. Therefore, we do not believe that 
authorization of incidental take resulting from airborne sound for 
pinnipeds is warranted, and airborne sound is not discussed further 
here.

Potential Effects on Marine Mammal Habitat

    The Navy's proposed activities at the project area would not result 
in permanent negative impacts to habitats used directly by marine 
mammals, but may have potential short-term impacts to food sources such 
as forage fish and invertebrates and may affect acoustic habitat (see 
masking discussion above). Physical alteration of the water column or 
bottom topography, as a result of pile driving training exercises would 
be of limited duration and intermittent spatial and temporal scale. 
Considering that all piles would be removed after each training 
exercise is completed, long term or permanent impacts would be 
unlikely. Pile driving would likely result in localized turbidity 
increases, which would not be expected to decrease water quality due to 
the existing high use of Port Hueneme Harbor by the Navy and Oxnard 
Harbor District. Port Hueneme Harbor moves over 8 billion dollars 
annually, and is the only commercial deep-water port between Los 
Angeles and San Francisco (Port of Hueneme, 2019). Additionally, the 
U.S. Army Corps of Engineers completed a port deepening project in 
2021, dredging the commercial harbor to reach a depth of 12 m (40 ft) 
for berthings (Port of Hueneme, 2021). Given the highly industrial 
nature of the proposed action area, and likely existing elevated 
turbidity due to run-off, hardened shorelines, and vessel traffic, the 
incremental increase in turbidity resulting from the proposed training 
exercises would not have a measurable impact on physical habitat. No 
permanent structures would be installed in the proposed action area. No 
permanent impacts to habitat are proposed for, or would occur as a 
result of, these proposed training exercises. Therefore, Navy training 
activities are not likely to have more than a localized and short-term 
effect on marine mammal habitat in the proposed action area.
    There are no known foraging hotspots or other ocean bottom 
structure of significant biological importance to marine mammals 
present in the marine waters of the project area. The Navy's training 
exercises in NBCV could have localized, temporary impacts on marine 
mammal habitat and their prey by increasing in-water sound pressure 
levels and slightly decreasing water quality. Increased noise levels 
may affect acoustic habitat (see masking discussion above) and 
adversely affect marine mammal prey in the vicinity of the project area 
(see discussion below). During impact and vibratory pile driving or 
removal, elevated levels of underwater noise would ensonify a portion 
of NBVC and nearby waters where both fishes and mammals occur and could 
affect foraging success. Additionally, marine mammals may avoid the 
area during construction, however, displacement due to noise is 
expected to be temporary and is not expected to result in long-term 
effects to the individuals or populations. Construction activities are 
of short duration and would likely have temporary impacts on marine 
mammal habitat through increases in underwater and airborne sound.
    Pile installation/removal may temporarily increase turbidity 
resulting from suspended sediments. Any increases would be temporary, 
localized, and minimal. In general, turbidity associated with pile 
installation is localized to about a 7.6-m (25-ft) radius around the 
pile (Everitt et al., 1980). Cetaceans are not expected to be close 
enough to the project pile driving areas to experience effects of 
turbidity, and pinnipeds could avoid localized areas of turbidity. 
Therefore, the impact from increased turbidity levels is expected to 
minimal for marine mammals. Furthermore, pile driving and removal at 
the project site would not obstruct movements or migration of marine 
mammals.
    Potential Pile Driving Effects on Prey--Pile driving produces 
continuous, non-impulsive sounds (i.e., vibratory pile driving) and 
intermittent, pulsed sounds (i.e. impact driving). Sound may affect 
marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton). Marine mammal prey varies by species, season, and 
location. Here, we describe studies regarding the effects of noise on 
known marine mammal prey.
    Marine invertebrates in the proposed action area encompass a 
diverse range of species, including mollusks, crabs, shrimp, snails, 
sponges, sea fans, isopods, and a diverse assemblage of polychaete 
worms (Chess and Hobson, 1997; Dugan et al., 2000; Proctor et al., 
1980; Talley et al., 2000; Thompson et al., 1993). Marine invertebrates 
are important food sources that support the base of the regional food 
chain (Linacre, 2004; Perry, 2003) and provide food for both harbor 
seals, which feed on crustaceans and shellfish, as well as California 
sea lions, which feed on squid. The benthic habitat within the proposed 
action area is predominantly soft bottomed, and heavily impacted by

[[Page 15971]]

anthropogenic use (e.g., by maintenance dredging).
    Very little is known about sound detection by aquatic invertebrates 
(Hawkins and Popper, 2017; Lovell et al., 2005; Popper, 2008). While 
data are limited, studies do suggest that most major invertebrates do 
not hear well, and crustaceans and cephalopods likely hear only low 
frequency sounds (Hanlon, 1987; Hill, 2009; Mooney et al., 2010; 
Offutt, 1970; Roberts and Breithaupt, 2016). Acoustic signals produced 
by crustaceans range from low-frequency rumbles (20 to 60 Hz) to high-
frequency signals 20 to 55 kHz (Edmonds et al., 2016; Henninger and 
Watson, 2005; Patek and Caldwell, 2006; Roberts and Breithaupt, 2016; 
Staaterman, 2016). In general, organisms may detect sound by sensing 
either the particle motion or pressure component of sound, or both. 
However, because any acoustic sensory capabilities of invertebrates (if 
present at all) are limited to detecting water motion, and water 
particle motion near a sound source falls off rapidly with distance, 
aquatic invertebrates are likely limited to detecting nearby low-
frequency sound sources rather than sound caused by pressure waves from 
distant sources unknown (Hawkins and Popper, 2017; Lovell et al., 2005; 
Popper, 2008). Recent research suggests that both behavioral and 
physiological impacts may be possible when crustaceans are exposed to 
repeated high levels of low frequency, high amplitude anthropogenic 
noise (Celi et al., 2015; Edmonds et al., 2016; Filiciotto et al., 
2014; Roberts and Breithaupt, 2016). With respect specifically to pile 
driving, the substrate borne vibrations can elicit alarm responses in 
mobile benthic epifauna such as crabs, while particle motion in the 
water column elicits a similar response in squid. While benthic 
invertebrates of many types would be expected in the proposed action 
area, squid would not be common (Jones et al., 2020; Roberts et al., 
2016).
    It is expected that most marine invertebrates would be sensitive to 
the low frequency, high amplitude sources, particularly impact pile 
driving, associated with the proposed training exercises, as alarm 
response to simulated pile driving has been observed in mollusks, 
crustaceans, and cephalopods (Jones et al., 2020; Roberts et al., 
2016). Any marine invertebrate capable of sensing sound may alter its 
behavior if exposed to sufficiently high levels of sound. Although 
individuals may be briefly exposed to pile driving noise associated 
with the proposed training exercises, intermittent exposures to pile 
driving noise are not expected to impact survival, growth, recruitment, 
or reproduction of widespread marine invertebrate populations, 
particularly given that invertebrate populations living within this 
highly industrialized environment are likely acclimated to fairly high 
levels of background noise. Therefore, impacts to invertebrates are 
expected to be minor and temporary.
    The nearshore areas of Port Hueneme are highly industrialized, and 
thus, represent relatively low quality fish habitat. Nevertheless, this 
area is inhabited by a range of pelagic and demersal fish species, many 
of which represent important forage species (Allen et al., 2006; Cross 
and Allen, 1993; Mueter, 2004). Small coastal pelagic fishes, such as 
the pacific sardine and northern anchovy, are important forage species 
for marine mammals, as are larger piscivorous species including 
mackerel, kelp bass (Paralabrax clathratus), and rockfish, which are 
also preyed upon by marine mammals (Koslow et al., 2015; Miller and 
Lea, 1972; Roedel, 1953).
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). All fishes have two sensory systems that can detect sound in the 
water: the inner ear, which functions similarly to the inner ear in 
other vertebrates, and the lateral line, which consists of a series of 
receptors along the body of a fish (Popper and Hawkins, 2018; Popper 
and Schilt, 2008). The lateral line detects particle motion at low 
frequencies from below 1 Hz up to at least 400 Hz (Coombs and 
Montgomery, 1999; Hastings and Popper, 2005; Higgs and Radford, 2013; 
Webb et al., 2008). The inner ear of fish generally detects relatively 
higher frequency sounds. The potential effects of noise on fishes 
depends on the overlapping frequency range, distance from the sound 
source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    All known fish species would be able to detect low-frequency noise 
associated with the proposed training exercises. Although hearing 
capability data only exist for fewer than 100 fish species, current 
data suggest that most fish detect sounds from 50 to 1,000 Hz (Hawkins 
and Popper, 2017; Popper, 2008; Popper et al., 2003; Popper et al., 
2014). It is believed that most fish have their best hearing 
sensitivity from 100 to 400 Hz (Hawkins and Popper, 2017; Popper, 
2008).
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality (summarized in Popper et al., 2014). However, in 
most fish species, hair cells in the ear continuously regenerate and 
loss of auditory function likely is restored when damaged cells are 
replaced with new cells. As a consequence, any hearing loss in fish may 
be as temporary as the timeframe required to repair or replace the 
sensory cells that were damaged or destroyed (Smith et al., 2006). 
Halvorsen et al. (2012a) showed that a TTS of 4-6 dB was recoverable 
within 24 hours for one species. Impacts would be most severe when the 
individual fish is close to the source and when the duration of 
exposure is long. Injury caused by barotrauma can range from slight to 
severe and can cause death, and is most likely for fish with swim 
bladders. Barotrauma injuries have been documented during controlled 
exposure to impact pile driving (Halvorsen et al., 2012b; Casper et 
al., 2013). PTS has not been documented in fish.
    Fish react to sounds that are especially strong and/or intermittent 
low-frequency sounds. Short duration, sharp sounds can cause overt or 
subtle changes in fish behavior and local distribution. The reaction of 
fish to noise depends on the physiological state of the fish, past 
exposures, motivation (e.g., feeding, spawning, migration), and other 
environmental factors. Hastings and Popper (2005) identified several 
studies that suggest fish may relocate to avoid certain areas of sound 
energy. Additional studies have documented effects of pile driving on 
fish; several are based on studies in support of large, multiyear 
bridge construction projects (e.g., Scholik and Yan 2001, 2002; Popper 
and Hastings 2009). Several studies have demonstrated that impulse 
sounds might affect the distribution and behavior of some fishes, 
potentially impacting foraging opportunities or increasing energetic 
costs (e.g., Fewtrell and McCauley, 2012; Pearson et al. 1992; Skalski 
et al. 1992; Santulli et al. 1999; Paxton et al. 2017). However, some 
studies have shown no or slight reaction to impulse sounds (e.g., Pena 
et al. 2013; Wardle et al. 2001; Jorgenson and Gyselman, 2009; Cott et 
al. 2012).
    Since the proposed action area is a relatively enclosed 
environment, sound would not propagate outside of Port Hueneme Harbor. 
Furthermore, only a limited number of fish may be exposed to loud 
sound, while most would be far enough from the sources for the sound 
level to have attenuated considerably. During a period of disrupted 
hearing,

[[Page 15972]]

fish would potentially be less sensitive to sounds produced by 
predators or prey, or to other acoustic information about their 
environment. Fish use sounds to detect both predators and prey, as well 
as for schooling, mating, and navigating (Hawkins and Popper, 2017; 
Popper et al., 2003). Masking can impede the flight response of fish 
from predators or may not allow fish to detect potential prey in the 
area. Long-term consequences to fish species are not expected, as any 
masking would be localized and short term.
    Behavioral responses to loud noise could include a startle 
response, such as the fish swimming away from the source, the fish 
``freezing'' and staying in place, or scattering (Popper, 2008). It is 
not anticipated that temporary behavioral reactions (e.g., temporary 
cessation of feeding or avoidance response) would affect the individual 
fitness of a fish, or a population as individuals are expected to 
resume normal behavior following the sound exposure. In general, 
impacts to marine mammal prey species are expected to be minor and 
temporary due to the short timeframe of the project.
    In summary, given the short daily duration of sound associated with 
individual pile driving and the small area being affected relative to 
available nearby habitat, pile driving activities associated with the 
proposed action are not likely to have a permanent, adverse effect on 
any fish habitat, or populations of fish species or other prey. Thus, 
we conclude that impacts of the specified activity are not likely to 
have more than short-term adverse effects on any prey habitat or 
populations of prey species. Further, any impacts to marine mammal 
habitat are not expected to result in significant or long-term 
consequences for individual marine mammals, or to contribute to adverse 
impacts on their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determinations.
    Harassment is the only type of take expected to result from these 
activities. For this military readiness activity, the MMPA defines 
``harassment'' as (i) Any act that injures or has the significant 
potential to injure a marine mammal or marine mammal stock in the wild 
(Level A harassment); or (ii) Any act that disturbs or is likely to 
disturb a marine mammal or marine mammal stock in the wild by causing 
disruption of natural behavioral patterns, including, but not limited 
to, migration, surfacing, nursing, breeding, feeding, or sheltering, to 
a point where the behavioral patterns are abandoned or significantly 
altered (Level B harassment).
    Authorized takes would be by Level B harassment only, in the form 
of disruption of behavioral patterns and/or TTS for individual marine 
mammals resulting from exposure to the pile driving activities. Based 
on the nature of the activity and the anticipated effectiveness of the 
mitigation measures (i.e., shutdown measures) discussed in detail below 
in the Proposed Mitigation section, Level A harassment is neither 
anticipated nor proposed to be authorized.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the proposed take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources.
    The Navy's proposed training activities includes the use of 
continuous (vibratory pile installation/removal) and impulsive (impact 
pile installation) sources, and therefore the RMS SPL thresholds of 120 
and 160 dB re 1 [mu]Pa are applicable.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). The Navy's 
training exercises includes the use of impulsive (impact pile driving) 
and non-impulsive (vibratory pile driving/removal) sources.
    These thresholds are provided in Table 4. The references, analysis, 
and methodology used in the development of the thresholds are described 
in NMFS' 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

[[Page 15973]]



                     Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                         PTS onset thresholds * (received level)
             Hearing group             -------------------------------------------------------------------------
                                                Impulsive                          Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans..........  Cell 1: L0-pk,flat: 219    Cell 2: LE, LF,24h: 199 dB.
                                         dB; LE, LF,24h: 1183 dB.
Mid-Frequency (MF) Cetaceans..........  Cell 3: L0-pk,flat: 230    Cell 4: LE, MF,24h: 198 dB.
                                         dB; LE, MF,24h: 1185 dB.
High-Frequency (HF) Cetaceans.........  Cell 5: L0-pk,flat: 202    Cell 6: LE, HF,24h: 173 dB.
                                         dB; LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)....  Cell 7: L0-pk.flat: 218    Cell 8: LE,PW,24h: 201 dB.
                                         dB; LE,PW,24h: 1185 dB.
Otariid Pinnipeds (OW) (Underwater)...  Cell 9: L0-pk,flat: 232    Cell 10: LE,OW,24h: 219 dB.
                                         dB LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS
  onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds
  associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
  exposure level (LE,) 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 are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    Sound Source Levels of Proposed Training Exercises--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. The Navy evaluated sound source level 
measurements available for certain pile types and sizes from similar 
environments to determine reasonable source levels likely to result 
from the proposed pile driving activities. The Navy determined that 
data from CALTRANS (2020) and NAVFAC SW (2020) provided the most 
applicable acoustic source data to use as proxy source levels for this 
proposed action. The Navy proposed, and NFMS agrees, that source level 
data from NAVFAC SW (2020) be used as proxy source levels for vibratory 
driving of 24-inch sheet piles because this reference provided noise 
data from the site of the proposed training exercise (i.e., data were 
recorded from Wharf 4 at NBVC). The Navy proposes, and NMFS agrees, 
that source level data from CALTRANS (2020) be used for all other pile 
sizes and installation methods as this reference provided data for the 
same or similar pile sizes and installation techniques, despite source 
levels having been recorded at different locations than the proposed 
training exercises (Table 5). Details are described below. Note that 
the source levels discussed here and provided in Table 5 represent the 
SPL referenced at a distance of 10 m from the source unless otherwise 
specified. Further, the Navy and NMFS assume that source levels 
attributed to vibratory removal of piles are equivalent or less than 
source levels attributed to the vibratory installation of pile.
    Vibratory or impact data is not available for 16-inch timber piles. 
Therefore, the Navy proposed, and NMFS agrees, that source levels for 
impact driving of 14-inch timber piles at the Ballena Bay in Alameda, 
California be used as a proxy values for impact driving 16-inch timber 
piles (CALTRANS, 2020) (Table 5). For vibratory driving of 16-inch 
timber piles, the Navy proposed, and NMFS concurs, to use source level 
data from vibratory driving of unknown sized timber piles used at the 
Norfolk Naval Station in Norfolk, Virginia (CALTRANS, 2020; Illingworth 
& Rodkin, 2015) as proxy values for the proposed training exercises 
(Table 5).
    Source level data for the installation and removal of 14-inch steel 
H-beam piles is limited. The Navy proposed, and NMFS agrees, that 
source levels for 15-inch steel H- been piles installed at Ballena Isle 
Marina in Alameda, California be used as proxy values for 14-inch steel 
H-beam piles during impact driving. This decision is based upon the 
piles similar size, the use of a vertical hammer placement (as opposed 
to battering at an angle), and the similarity in water depths at the 
action sites (Table 5). The Navy also proposed, and NMFS agrees, that 
source levels for 10-inch steel H-beam piles installed during the San 
Rafeal Canal project in San Rafeal, California (CALTRANS, 2020) be used 
as proxy values for vibratory driving of 14-inch steel H beam piles 
during vibratory driving (Table 5).

                      Table 5--Summary of Unattenuated In-Water Pile Driving Source Levels
----------------------------------------------------------------------------------------------------------------
                                                                                                    SELss (dB re
                                                                   Peak SPL (dB   RMS SPL (dB re  1 [micro]Pa\2\
          Pile driving method               Pile description           re 1        1 [micro]Pa)        sec)
                                                                    [micro]Pa)
----------------------------------------------------------------------------------------------------------------
Impact................................  Timber (16-in)..........             180             170             160
                                        Steel H beam (14-in)....             195             180             170
Vibratory (installation and removal)..  Timber (16-in)..........  ..............             162  ..............
                                        Steel sheet (24-in).....  ..............         \1\ 159  ..............
                                        Steel H beam (14-in)....  ..............             147  ..............
----------------------------------------------------------------------------------------------------------------
\1\ The RMS SPL for vibratory installation of 24-inch steel sheets was recorded 11 m from the source.


[[Page 15974]]

    Level B Harassment Zones--Transmission loss (TL) is the decrease in 
acoustic intensity as an acoustic pressure wave propagates out from a 
source. TL parameters vary with frequency, temperature, sea conditions, 
current, source and receiver depth, water depth, water chemistry, and 
bottom composition and topography. The general formula for underwater 
TL is:

TL = B * log10 (R1/R2),

Where:

B = transmission loss coefficient (assumed to be 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. The recommended TL coefficient for most nearshore 
environments is the practical spreading value of 15. This value results 
in an expected propagation environment that would lie between spherical 
and cylindrical spreading loss conditions, which is the most 
appropriate assumption for the Navy's proposed training exercises in 
the absence of specific modelling.
    All Level B harassment isopleths are reported in Table 7 
considering RMS SSLs for impact and vibratory pile driving, 
respectively. It should be noted that based on the geography of the 
NBVC and the surrounding land masses, port infrastructure, and the 
shoreline, the Level B harassment isopleths would reach a maximum of 
790 m (2,592 ft) for Wharf 4 South, 795 m (2,601 ft) for Wharf 4 East, 
and 655 m (2,149 ft) for Wharf D (See Figure 6-1, 6-2, and 6-3 in the 
Navy's application). Although it is known that there can be leakage or 
diffraction around such barriers, the assumption herein is that any 
impervious barriers would contain all pile driving noise associated 
with the Proposed Action.
    Level A Harassment Zones--The ensonified area associated with Level 
A harassment is more technically challenging to predict due to the need 
to account for a duration component. Therefore, NMFS developed an 
optional User Spreadsheet tool to accompany the Technical Guidance that 
can be used to relatively simply predict an isopleth distance for use 
in conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources, such as vibratory and impact pile driving, the 
optional User Spreadsheet tool predicts the distance at which, if a 
marine mammal remained at that distance for the duration of the 
activity, it would be expected to incur PTS. Inputs used in the 
optional User Spreadsheet tool are reported in Table 6, and the 
resulting estimated isopleths are reported in Table 7.

                                                          Table 6--NMFS User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Vibratory pile driving                                      Impact pile driving
                                    --------------------------------------------------------------------------------------------------------------------
                                      16-inch timber piles    14-inch steel H beam    24-inch steel sheet    16-inch timber piles   14-inch steel H beam
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used...............  A.1) Non-Impul, Stat,   A.1) Non-Impul, Stat,   A.1) Non-Impul, Stat,  E.1) Impact pile       E.1) Impact pile
                                      Cont.                   Cont.                   Cont.                  driving.               driving
Source Level (SPL).................  162 dB RMS............  147 dB RMS............  159 dB RMS...........  160 dB SEL...........  170 dB SEL
Transmission Loss Coefficient......  15....................  15....................  15...................  15...................  15
Weighting Factor Adjustment (kHz)..  2.5...................  2.5...................  2.5..................  2....................  2
Time to install/remove single pile   30....................  30....................  20...................  .....................  .....................
 (minutes).
Number of strikes per pile.........  ......................  ......................  .....................  1,800................  1,800
Piles to install/remove per day....  2.....................  2.....................  3....................  2....................  2
Distance of sound pressure level     10....................  10....................  11...................  10...................  10
 measurement (m).
--------------------------------------------------------------------------------------------------------------------------------------------------------


           Table 7--Distances to Level A Harassment, by Hearing Group, and Level B Harassment Thresholds Per Pile Type and Pile Driving Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                            Level A harassment       Level A      Level B      Level B
                                                                                               distance (m)         harassment   harassment   harassment
                                                                             Piles per  --------------------------    areas       distance      areas
                  Activity                          Pile description            day                                (km\2\) for    (m) all    (km\2\) for
                                                                                              PW           OW      all hearing    hearing    all hearing
                                                                                                                    groups \1\     groups     groups \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation/Removal.............  16-inch Timber Piles.........            3          4.8          0.3         <0.1    \2\ 6,310         <0.3
                                             14-inch Steel H Beam.........            2          0.5            0         <0.1          631         <0.3
                                             24-inch Steel Sheet..........            3          3.4          0.2         <0.1    \2\ 4,379         <0.3
Impact Installation/Removal................  16-inch Timber Piles.........            3         36.8          2.7         <0.1           47         <0.1
                                             14-inch Steel H-Beam.........            2        170.6         12.4         <0.1          216         <0.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Harassment areas have been truncated where appropriate to account for land masses.
\2\ The maximum harassment distances are approximately 790 m (2,592 ft) for Wharf 4 South, 795 m (2,601 ft) for Wharf 4 East, and 655 m (2,149 ft) for
  Wharf D.


[[Page 15975]]

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information that 
will inform the take calculations. Here we also describe how the 
occurrence information provided is synthesized to produce a 
quantitative estimate of the take that is reasonably likely to occur 
and proposed for authorization.

California Sea Lion

    No density or abundance numbers exist for California sea lions in 
the proposed action area. Therefore, to quantitatively assess exposure 
of marine mammals to noise from pile driving conducted as part of the 
Navy's training exercises, the Navy used estimates derived from recent 
monitoring efforts to determine the number of animals potentially 
exposed in the Level A and Level B harassment zones in any one day of 
pile driving or extraction.
    NBVC biologists have been conducting opportunistic surveys of 
California sea lions hauled out at Wharf D somewhat regularly since 
2010. California sea lions have been observed regularly hauling out on 
structures (i.e., docks, barges, and boats) near Wharf D, sometimes in 
large numbers. They often crowd onto these structures, making it 
difficult for observers to determine the total number of sea lions 
present. Some of the counts at Wharf D include pinnipeds present in the 
water, which could also include harbor seals. California sea lions are 
the predominant pinniped species at Port Hueneme Harbor, so the 
assumption is that nearly all animals present would be California sea 
lions. The number of California sea lions present in the proposed 
action area at Wharf D is variable by month and by year. The maximum 
number of California sea lions counted at Wharf D during an individual 
survey day was 342 (1/15/2021). No other pinniped species have been 
observed at Wharf D during these surveys. While these count data 
provide a snapshot of pinniped presence in the action area, they do not 
provide rate of turnover over time of different pinnipeds present in 
the proposed action area; nor do they provide long-term sea lion 
presence patterns.
    Since the fall of 2020, there have also been efforts to count 
pinnipeds in the water near Wharf 4; however, these monitoring efforts 
have been sporadic, taking place for an hour at a time from a boat 
launch just south of Wharf 4. Monitoring efforts have observed anywhere 
from zero to 85 sea lions in an hour (see Figure 6-4 in the Navy's 
application). Additionally, the same individuals may have been observed 
multiple times within the survey period. Therefore, the number of 
California sea lions assumed to be present in the proposed action area 
at Wharf 4 is variable.
    Based on these data, the Navy conservatively estimates that 342 
California sea lions (i.e., the maximum number of California sea lions 
observed in the proposed action area on a single day) may be present in 
the proposed action area each day and be behaviorally harassed during 
the 96 days of pile driving proposed as part of the Navy's training 
exercises. Therefore, the Navy requests, and NMFS proposes to 
authorize, 36,960 instances of take by Level B harassment for 
California Sea Lions. No take Level A harassment is anticipated or 
proposed to be authorized for California sea lions due to the small 
Level A harassment zones (Table 7) and implementation of shutdown 
zones, which would be larger than Level A harassment isopleths, as 
described below in the Proposed Mitigation section.

Harbor Seals

    No density or abundance numbers exist for harbor seals in the 
proposed action area. Harbor seals have only been observed by NBVC 
biologists near Wharf 4; no harbor seals have been detected at Wharf D. 
The maximum number of harbor seals seen over the course of an hour of 
observation was 5 seals. This was 5.88% of the maximum number of 
California sea lions observed at Wharf D (N = 85). Therefore, to 
account for the potential for harbor seals in the proposed action area, 
the Navy assumes that 5.88 percent of the maximum number of California 
sea lions observed animals at Wharf D (5.88 percent of 342, or 20.1 
[rounded up to 21] animals per day) are harbor seals.
    Based on these data, the Navy conservatively estimates that 21 
harbor seals may be present in the proposed action area each day and be 
behaviorally harassed during the 96 days of pile driving proposed as 
part of the Navy's training exercises. Therefore, the Navy requests, 
and NMFS proposes to authorize, 2,016 instances of take by Level B 
harassment for harbor seals. No take by Level A harassment is 
anticipated or proposed to be authorized for harbor seals. While the 
Level A harassment zone for impact pile driving 14-inch steel H-beams 
is 170.6 m, harbor seals are considered rare in the proposed action 
area (Department of the Navy, 2019) minimizing the likelihood of Level 
A harassment take. In addition, measures described below in the 
Proposed Mitigation section, including shutdown measures and the 
implementation of lookouts at stations where the entire Level B zones 
are observable, will minimize the likelihood that harbor seals will be 
in this larger zone during impact driving of steel H-beams and that 
they would incur PTS before pile driving activities could be shut down. 
Therefore NMFS agrees with the Navy and is not proposing to authorize 
any takes by Level A harassment takes for harbor seals during the 
Navy's proposed training exercises.
    In summary, the total amount of Level A harassment and Level B 
harassment proposed to be authorized for each marine mammal stock is 
presented in Table 8.

        Table 8--Proposed Amount of Take as a Percentage of Stock Abundance, by Stock and Harassment Type
----------------------------------------------------------------------------------------------------------------
                                                             Proposed authorized take
            Species                   Stock      ------------------------------------------------   Percent of
                                                      Level A         Level B          Total           stock
----------------------------------------------------------------------------------------------------------------
California Sea Lion...........  U.S.............               0          36,960          36,960            14.3
Harbor Seal...................  California......               0           2,016           2,016            6.51
----------------------------------------------------------------------------------------------------------------

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include

[[Page 15976]]

information about the availability and feasibility (economic and 
technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The Navy must employ the following standard mitigation measures, as 
included in the proposed IHA:
     Conduct briefings between construction supervisors and 
crews, the marine mammal monitoring team, and Navy staff prior to the 
start of all in-water pile driving activity, and when new personnel 
join the work, to ensure that responsibilities, communication 
procedures, marine mammal monitoring protocols, and operational 
procedures are clearly understood.
     During all in-water work other than pile driving (e.g., 
pile placement, boat use), in order to prevent injury from physical 
interaction with construction equipment, a shutdown zone of 10 m (33 
ft) will be implemented. If a marine mammal comes within 10 m (33 ft), 
operations shall cease and vessels shall reduce speed to the minimum 
level required to maintain steerage and safe working conditions. If 
human safety is at risk, the in-water activity will be allowed to 
continue until it is safe to stop.
     The Navy must establish shutdown zones for all for in-
water pile driving activities. 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). Shutdown zones will vary based on the type 
of pile installation/removal activity (See Table 9). Here, shutdown 
zones are larger than the calculated Level A harassment isopleths shown 
in Table 7. The placement of lookouts during all pile driving 
activities (described in detail in the Proposed Monitoring and 
Reporting Section) will ensure that the entirety of all shutdown zones 
and Level A harassment zones are visible during pile installation and 
removal.

                         Table 9--Shutdown Zones During In-Water Pile Driving Activities
----------------------------------------------------------------------------------------------------------------
                                                                                           Distance (m)
                   Activity                             Pile description         -------------------------------
                                                                                        PW              OW
----------------------------------------------------------------------------------------------------------------
Vibratory Installation/Removal................  16-inch Timber Piles............              15              15
                                                14-inch Steel H Beam............              15              15
                                                24-inch Steel Sheet.............              15              15
Impact Installation/Removal...................  16-inch Timber Piles............              40              40
                                                14-inch Steel H Beam............             175             175
----------------------------------------------------------------------------------------------------------------

     The Navy must delay or shutdown all in-water pile driving 
activities should an animal approach or enter the appropriate shutdown 
zone. The Navy may resume in-water pile driving activities after one of 
the following conditions have been met: (1) the animal is observed 
exiting the shutdown zone; (2) the animal is thought to have exited the 
shutdown zone based on a determination of its course, speed, and 
movement relative to the pile driving location; or (3) the shutdown 
zone has been clear from any additional sightings for 15 minutes.
     The Navy shall employ lookouts trained in marine mammal 
identification and behaviors to monitor marine mammal presence in the 
action area. Requirements for numbers and locations of observers will 
be based on hammer type, pile material, and Seabees training location 
as described in Section 5 of the IHA. Lookouts must track marine 
mammals observed anywhere within their visual range relative to in-
water construction activities, and estimate the amount of time a marine 
mammal spends within the Level A or Level B harassment zones while pile 
driving activities are underway. The Navy must monitor the project 
area, including the Level B harassment zones, to the maximum extent 
possible based on the required number of lookouts, required monitoring 
locations, and environmental conditions. For all pile driving and 
removal activities, at least one lookout must be used.
     The placement of the lookouts during all pile driving and 
removal activities must ensure that the entire applicable shutdown 
zones are visible during all in-water pile installation and removal. 
One observer must be placed in a position to implement shutdown/delay 
procedures, when applicable, by notifying the hammer operator of a need 
for a shutdown of pile driving or removal.
     Prior to the start of pile driving or removal, the 
shutdown zone(s) must be monitored for a minimum of 30 minutes to 
ensure that they are clear of marine mammals (i.e., pre-clearance 
monitoring). Pile driving will only commence once observers have 
declared the shutdown zone(s) are clear of marine mammals. Monitoring 
must also take place for 30 minutes post-completion of pile driving;
     If in-water work ceases for more than 30 minutes, the Navy 
must conduct pre-clearance monitoring of both the Level B harassment 
zone and shutdown zone;
     Pre-start clearance monitoring must be conducted during 
periods of visibility sufficient for the lead lookout to determine that 
the shutdown zones indicated in Table 9 are clear of marine mammals. 
Pile driving may commence following 30 minutes of observation when the 
determination is made that the

[[Page 15977]]

shutdown zones are clear of marine mammals;
     The Navy must use soft start techniques when impact pile 
driving. Soft start requires contractors to provide an initial set of 
three strikes at reduced energy, followed by a 30 second waiting 
period, then two subsequent reduced energy strike sets. A soft start 
must 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 starts will not be used for vibratory pile 
installation and removal. Lookouts shall begin observing for marine 
mammals 30 minutes before ``soft start'' or in-water pile installation 
or removal begins.
     For any marine mammal species for which take by Level B 
harassment has not been requested or authorized, in-water pile 
installation/removal will shut down immediately when the animals are 
sighted;
     If take by Level B harassment 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 
of them.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     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.

Visual Monitoring

    Monitoring must be conducted by qualified lookouts with support 
from Navy biologists, in accordance with the following:
     Navy biologists will train and certify lookouts in 
accordance with the mitigation, monitoring and reporting requirements 
of the issued IHA;
     NMFS will approve resumes of the Navy biologists who 
provide the training to the lookouts;
     Lead lookouts will be selected by Navy biologists among 
the best performing lookouts;
     All lookouts will maintain contact via either handheld 
communication devices or flags to signal sightings and shutdowns;
     Lookouts shall be placed at vantage points to monitor for 
marine mammals and implement shutdown/delay procedures when applicable 
by calling for the shutdown to the hammer operator;
     The Lead lookout will be located within auditory range of 
the pile driving team and will have primary responsibility for calling 
activity shutdowns;
     Lookouts shall use a hand-held GPS device, rangefinder or 
marker buoy to verify the required monitoring distance from the project 
site;
     Monitoring shall occur in all-weather until training has 
concluded for the day;
     Lookouts must scan the waters within the Level A 
harassment and Level B harassment zones using binoculars (10x42 or 
similar) and or the naked eye and make visual observations of marine 
mammals present; and
     Lookouts must record all observations of marine mammals as 
described in the Section 5 of the IHA, regardless of distance from the 
pile being driven. Lookouts shall document any behavioral reactions in 
concert with distance from piles being driven or removed;
    Lookouts must have the following additional qualifications:
     Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the water's surface 
with ability to estimate target size and distance; use of binoculars 
may be necessary to correctly identify the target;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.

Reporting

    The Navy must submit a draft marine mammal monitoring report to 
NMFS within 90 days after the completion of pile driving training 
activities, or 60 days prior to a requested date of issuance of any 
future IHAs for projects at the same location, whichever comes first. 
NMFS would provide comments within 30 days after receiving the draft 
report, and the Navy would address the comments and submit revisions 
within 30 days of receipt. If no comments are received from NMFS within 
30 days, the draft report would be considered as final.
    The draft and final marine mammal monitoring reports must be 
submitted to [email protected] and 
[email protected]. The reports shall include an overall 
description of work completed, a narrative regarding marine mammal

[[Page 15978]]

sightings, and associated data sheets. Specifically, the reports must 
include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact or vibratory) and the total 
equipment duration for vibratory installation and removal for each pile 
or total number of strikes for each pile for impact driving;
     Lookout locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of lookout shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Description of any deviation from initial proposal in pile 
numbers, pile types, average driving times, etc.;
     Brief description of any impediments to obtaining reliable 
observations during training periods; and
     Description of any impediments to complying with the 
aforementioned mitigation measures.
    Lookouts must record all incidents of marine mammal occurrence in 
the area in which take is anticipated regardless of distance from 
activity, and shall document any behavioral reactions in concert with 
distance from piles being driven or removed. Specifically, lookouts 
must record the following:
     Name of lookout who sighted the animal(s) and lookout 
location and activity at time of sighting;
     Time of sighting;
     Identification of the animal(s) (e.g., genus/species, 
lowest possible taxonomic level, or unidentified), lookout confidence 
in identification, and the composition of the group if there is a mix 
of species;
     Distance and bearing of each marine mammal observed 
relative to the pile being driven for each sighting (if pile driving 
was occurring at time of sighting);
     Estimated number of animals (min/max/best estimate);
     Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, sex class, etc.);
     Animal's closest point of approach and estimated time 
spent within the harassment zone;
     Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses thought to have resulted from the 
activity (e.g., no response or changes in behavioral state such as 
ceasing feeding, changing direction, flushing, or breaching);
     Number of marine mammals detected within the harassment 
zones and shutdown zones, by species; and
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    Reporting Injured or Dead Marine Mammals
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the IHA-holder must 
immediately cease the specified activities and report the incident to 
the Office of Protected Resources (OPR) 
([email protected]; [email protected]) and to the 
West Coast Regional Stranding Coordinator (1-866-767-6114) as soon as 
feasible. The incident 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.
    If the death or injury was clearly caused by the specified 
activity, the Navy must immediately cease the specified activities 
until NMFS is able to review the circumstances of the incident and 
determine what, if any, additional measures are appropriate to ensure 
compliance with the terms of the proposed IHA. The Navy must not resume 
their activities until notified by NMFS that they can continue.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338; 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the discussion of our analysis applies to both 
California sea lions and harbor seals, given that the anticipated 
effects of this activity on these different marine mammal stocks are 
expected to be similar. There is little information about the nature or 
severity of the impacts, or the size, status, or structure of any of 
these species or stocks that would lead to a different analysis for 
this activity.
    NMFS has identified key factors which may be employed to assess the 
level of analysis necessary to conclude whether potential impacts 
associated with a specified activity should be considered negligible. 
These include (but are not limited to) the type and magnitude of 
taking, the amount and importance of the available habitat for the 
species or stock that is affected, the duration of the anticipated 
effect to the species or stock, and the status of the species or stock.
    NMFS does not anticipate that serious injury or mortality would 
occur as a result of the Navy's planned activity given the nature of 
the activity, even in the absence of required mitigation. Pile driving 
activities associated with the Navy's pile driving training exercises, 
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, incidental to underwater 
sounds generated from pile driving. Potential takes could occur if 
individuals are present in zones

[[Page 15979]]

ensonified above the thresholds for Level B harassment, identified 
above, while activities are underway. Level A harassment is not 
anticipated or proposed to be authorized, as described in the Estimated 
Take section, given the construction method and the implementation of 
the planned mitigation measures, including soft start measures during 
impact pile driving and shutdown zones.
    Vibratory and impact hammers will be the primary methods of 
installation. Vibratory pile driving produces lower SPLs than impact 
pile driving and will be the predominant construction method used 
during training (Table 1). The rise time of the sound produced by 
vibratory pile driving is slower, reducing the probability and severity 
of injury. Impact pile driving produces short, sharp pulses with higher 
peak levels and much sharper rise time to reach those peaks. When 
impact pile driving is used, implementation of soft start and shutdown 
zones will significantly reduce any possibility of injury. Given 
sufficient ``notice'' through use of soft starts (for impact driving), 
marine mammals are expected to move away from a sound source prior to 
it becoming potentially injurious. The Navy will use at least one 
lookout stationed strategically to increase detectability of marine 
mammals, enabling a high rate of success in implementation of shutdowns 
to avoid injury.
    Exposures to elevated sound levels produced during pile driving and 
removal in NBVC may cause behavioral disturbance of some individuals, 
however behavioral responses of marine mammals are expected to be mild, 
short term, and temporary. The Navy's proposed activities and 
associated impacts will occur within a limited, confined area of the 
stocks' range. The project area is concentrated within two wharfs and 
the Level B harassment zones would be truncated by land. Given that 
pile driving and removal would occur for only short durations (i.e., 4 
training sessions lasting up to 24 days each) on nonconsecutive days, 
any harassment occurring would be temporary. Pinnipeds swim, dive, 
mill, and haul out in and around Port Hueneme, but there is no data 
regarding the rate of turnover over time of different pinnipeds present 
in the proposed action are. Further there is no information regarding 
long-term pinniped presence patterns. Due to the nature of the proposed 
training exercise, we can presume that some individual harbor seals and 
California sea lions will be repeatedly taken. Repeated, sequential 
exposure to pile driving noise over a long duration could result in 
more severe impacts to individuals that could affect a population; 
however, the number of non-consecutive pile driving days for this 
project means that these types of impacts are not anticipated.
    Effects on individuals that are taken by Level B harassment, as 
enumerated in the Estimated Take section, 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). Marine mammals within the 
Level B harassment zones may not show any visual cues they are 
disturbed by activities or they could become alert, avoid the area, 
leave the area, or display other mild responses that are not observable 
such as changes in vocalization patterns. Most likely, individuals will 
simply 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 Southern 
California, which have taken place with no known long-term adverse 
consequences from behavioral harassment (e.g., December 27, 2021, 86 FR 
73257; October 31, 2022, 87 FR 65578). 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 both California 
sea lions and harbor seals have been observed in the NVBC, they are 
frequently observed along the nearshore waters of Southern California 
and have been observed hauling outside the mouth of Port Hueneme Harbor 
(Department of the Navy, 2019) suggesting they have available habitat 
outside of the NBVC to use while the proposed activity is occurring. 
While vibratory pile driving associated with the proposed project may 
produce sounds above ambient noise, the project site itself is located 
in an industrialized port, the entire ensonified area is within in the 
NBVC, and sounds produced by the proposed activities are anticipated to 
quickly become indistinguishable from other background noise in port as 
they attenuate to near ambient SPLs moving away from the project site. 
Therefore, we expect that animals disturbed by project sound would 
simply avoid the area and use more-preferred habitats.
    Additionally, and as noted previously, some subset of the 
individuals that are behaviorally harassed could also simultaneously 
incur some small degree of TTS for a short duration of time. Because of 
the small degree anticipated, though, any TTS potentially incurred here 
would not be expected to adversely impact individual fitness, let alone 
annual rates of recruitment or survival.
    More generally, there are no known calving or rookery grounds 
within the project area. Because the Navy's activities could occur 
during any season, takes may occur during important feeding times. 
However, the project area represents a small portion of available 
foraging habitat and impacts on marine mammal feeding for all species 
should be minimal.
    The project also is not expected to have significant adverse 
effects on affected marine mammal habitat. The project activities would 
not modify existing marine mammal habitat for a significant amount of 
time. Impacts to the immediate substrate are anticipated, but these 
would be limited to minor, temporary suspension of sediments, which 
could impact water quality and visibility for a short amount of time 
but which would not be expected to have any effects on individual 
marine mammals. Any impacts on marine mammal prey that would occur 
during the Navy's planned activity would have, at most, short-term 
effects on foraging of individual marine mammals, and likely no effect 
on the populations of marine mammals as a whole. The activities may 
cause some fish to temporarily 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 and the 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. Indirect effects 
on marine mammal prey during the construction are expected to be minor, 
and these effects are unlikely to cause substantial effects on marine 
mammals at the individual level, with no expected effect on annual 
rates of recruitment or survival. Overall, the area impacted by the 
project is very small compared to the available surrounding habitat, 
and does not include habitat of particular importance.
    It is unlikely that minor noise effects in a small, localized area 
of habitat

[[Page 15980]]

would have any effect on the stocks' annual rates of recruitment or 
survival. In combination, we believe that these factors, as well as the 
available body of evidence from other similar activities, demonstrate 
that the potential effects of the specified activities would have only 
minor, short-term effects on individuals. The specified activities are 
not expected to impact rates of recruitment or survival and would, 
therefore, not result in population-level impacts.
    In summary and as described above, the following factors primarily 
support negligible impact determinations for the affected stocks of 
California sea lions and harbor seals that the impacts resulting from 
this activity are not expected to adversely affect any of the species 
or stocks through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or proposed 
for authorization;
     Take by Level A harassment of California sea lions and 
harbor seals is not anticipated or proposed for authorization;
     The Navy would implement mitigation measures including 
soft-starts for impact pile driving and shutdown zones to minimize the 
numbers of marine mammals exposed to injurious levels of sound, and to 
ensure that take by Level A harassment does not occur.
     The anticipated incidents of Level B harassment consist 
of, at worst, temporary modifications in behavior or TTS 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 all species and does 
not include habitat areas of special significance (Biologically 
Important Areas or ESA-designated critical habitat);
     The intensity of anticipated takes by Level B harassment 
is relatively low for all stocks and would not be of a duration or 
intensity expected to result in impacts on reproduction or survival; 
and
     The presumed efficacy of the proposed 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 proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks would 
not have an unmitigable adverse impact on the availability of such 
species or stocks for taking for subsistence purposes.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species.
    No incidental take of ESA-listed species is proposed for 
authorization or expected to result from this activity. Therefore, NMFS 
has determined that formal consultation under section 7 of the ESA is 
not required for this action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the Navy for conducting up to four pile driving 
training exercises at NBVC for a year after the date of issuance of the 
IHA, provided the previously mentioned mitigation, monitoring, and 
reporting requirements are incorporated. A draft of the proposed IHA 
can be found at: www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed 
action. We also request comment on the potential renewal of this 
proposed IHA as described in the paragraph below. Please include with 
your comments any supporting data or literature citations to help 
inform decisions on the request for this IHA or a subsequent renewal 
IHA.
    On a case-by-case basis, NMFS may issue a one-time, 1 year renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical activities as described in the Description of Proposed 
Activities section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activities section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    Upon review of the request for renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS determines 
that there are no more than minor changes in the activities, the 
mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: March 9, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-05242 Filed 3-14-23; 8:45 am]
BILLING CODE 3510-22-P