[Federal Register Volume 84, Number 227 (Monday, November 25, 2019)]
[Notices]
[Pages 64847-64872]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-25471]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XR035


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel 
Project in Virginia Beach, Virginia

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 Chesapeake Tunnel Joint 
Venture (CTJV) for authorization to take marine mammals incidental to 
Parallel Thimble Shoal Tunnel Project (PTST) in Virginia Beach, 
Virginia. 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-year renewal that could be issued under certain circumstances and 
if all requirements are met, as described in Request for Public 
Comments at the end of this notice. NMFS will consider public comments 
prior to making any final decision on the issuance of the requested 
MMPA authorizations and agency responses will be summarized in the 
final notice of our decision.

DATES: Comments and information must be received no later than December 
26, 2019.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent 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 received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act 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: Robert Pauline, 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: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are issued or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization may be provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for

[[Page 64848]]

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 such 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 
such takings are set forth.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

National Environmental Policy Act

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

Summary of Request

    On May 24, 2019, NMFS received a request from the CTJV for an IHA 
to take marine mammals incidental to pile driving and removal at the 
Chesapeake Bay Bridge and Tunnel (CBBT) near Virginia Beach, Virginia. 
The application was deemed adequate and complete on October 11, 2019. 
The CTJV's request is for take of small numbers of harbor seal (Phoca 
vitulina), gray seal (Halichoerus grypus), bottlenose dolphin (Tursiops 
truncatus), harbor porpoise (Phocoena phocoena) and humpback whale 
(Megaptera novaeangliae) by Level A and Level B harassment. Neither 
CTJV nor NMFS expects serious injury or mortality to result from this 
activity and, therefore, an IHA is appropriate.
    NMFS previously issued an IHA to the CTJV for similar work (83 FR 
36522; July 30, 2018). However, due to design and schedule changes only 
a small portion of that work was conducted under the issued IHA. This 
proposed IHA covers one year of a five-year project.

Description of Proposed Activity

Overview

    The CTJV has requested authorization for take of marine mammals 
incidental to in-water construction activities associated with the PTST 
project. The project consists of the construction of a two-lane 
parallel tunnel to the west of the existing Thimble Shoal Tunnel, 
connecting Portal Island Nos. 1 and 2 of the CBBT facility which 
extends across the mouth of the Chesapeake Bay near Virginia Beach, 
Virginia. Upon completion, the new tunnel will carry two lanes of 
southbound traffic and the existing tunnel will remain in operation and 
carry two lanes of northbound traffic. The PTST project will address 
existing constraints to regional mobility based on current traffic 
volume along the facility. Construction will include the installation 
of 878 piles over 188 days as shown below:

 180 12-inch timber piles
 140 36-inch steel pipe piles
 500 36-inch interlocked pipes
 58 42-inch steel casings

    These will be installed using impact driving, vibratory driving and 
drilling with down-the-hole (DTH) hammers. Some piles will be removed 
via vibratory hammer. These activities will introduce sound into the 
water at levels which are likely to result in behavioral harassment or 
auditory injury based on expected marine mammal presence in the area. 
In-water construction associated with the project is anticipated to 
begin in fall of 2019.

Dates and Duration

    Work authorized under the proposed IHA is anticipated to take 188 
days and would occur during standard daylight working hours of 
approximately 8-12 hours per day depending on the season. In-water work 
would occur every month with the exception of September and October.
    The PTST project has been divided into four phases over 5 years. 
Phase I commenced in June 2017 and consisted of upland pre-tunnel 
excavation activities, while Phase IV is scheduled to be completed in 
May of 2022. In-water activities are limited to Phase II and, 
potentially, Phase IV (if substructure repair work is required at the 
fishing pier and/or bridge trestles and abutments).

Specific Geographic Region

    The PTST project is located between Portal Island Nos. 1 and 2 of 
the CBBT as shown in Figure 1. A tunnel will be bored underneath the 
Thimble Shoal Channel connecting the Portal Islands located near the 
mouth of the Chesapeake Bay. The CBBT is a 23-mile (37 km) long 
facility that connects the Hampton Roads area of Virginia to the 
Eastern Shore of Virginia. Water depths within the PTST construction 
area range from 0 to 60 ft (18.2 m) below Mean Lower Low Water (MLLW). 
The Thimble Shoal Channel is 1,000 ft (305 m) wide, is authorized to a 
depth of -55 ft (16.8 m) below MLLW, and is maintained at a depth of 50 
ft (15.2 m) MLLW.

[[Page 64849]]

[GRAPHIC] [TIFF OMITTED] TN25NO19.001

Detailed Description of Specific Activity

    The PTST project consists of the construction of a two-lane 
parallel tunnel to the west of the existing Thimble Shoal Tunnel, 
connecting Portal Island Nos. 1 and 2. Construction of the tunnel 
structure will begin on Portal Island No. 1 and move from south to 
north to Portal Island No. 2.
    The tunnel boring machine (TBM) components will be barged and 
trucked to Portal Island No. 1. The TBM will be assembled within an 
entry/launch portal that will be constructed on Portal Island No. 1. 
The machine will then both excavate material and construct the tunnel 
as it progresses from Portal Island No. 1 to Portal Island No. 2.
    Precast concrete tunnel segments will be transported to the TBM for 
installation. The TBM will assemble the tunnel segments in-place as the 
tunnel is bored. After the TBM reaches Portal Island No. 2, it will be 
disassembled, and the components will be removed via an exit/receiving 
portal on Portal Island No. 2. After the tunnel structure is completed, 
final upland work for the PTST Project will include installation of the 
final roadway, lighting, finishes, mechanical systems, and other 
required internal systems for tunnel use and function. In addition, the 
existing fishing pier will be repaired and refurbished.
    The new parallel two-lane tunnel is 6,350 ft (1935.5 m) in overall 
total length with 5,356 linear ft (1632.5 m) located below Mean High 
Water (MHW). Descriptions of upland activities may be found in the 
application but such actions will not affect marine mammals and are not 
described here.
    Proposed in-water activities include the following and are shown in 
Table 1:
     Temporary dock construction: Construction of a 32,832 
ft\2\ (3.050 m\2\) working platform on the west side of Portal Island 
No. 1. This construction includes temporary in-water installation of 58 
36-inch piles. A 42-inch steel casing will initially be drilled with a 
DTH hammer for each of the 36-inch piles which will then be installed 
with an impact hammer. A bubble curtain will be used during the impact 
driving of 47 of the 36-inch piles while 11 piles are expected to be 
installed using the impact hammer without a bubble curtain due to water 
depth of less than 10 ft.
     Mooring dolphins: An estimated 180 12-inch timber piles 
will be used for construction of the temporary mooring dolphins (120 
piles at Portal Island No. 1 and 60 piles at Portal Island No. 2) and 
will be installed and removed using a vibratory hammer. However, should 
refusal be encountered prior to design tip elevation when driving with 
the vibratory hammer an impact hammer will be used to drive the 
remainder of the pile length. No bubble curtains will be utilized for 
the installation of the timber piles.
     Construction of two temporary Omega trestles: 36 in-water 
36-inch diameter steel pipe piles will be installed at Portal Island 1 
along with 28 in-water 36-inch diameter steel pipe piles at Island 2. 
These trestles will be offset to the west side of each engineered berm, 
extending

[[Page 64850]]

approximately 659 ft (231.7 m) channelward from Portal Island Nos. 1 
and 2, respectively.
     Construction of two engineered berms, approximately 1,395 
ft (425 m) in length for Portal Island No. 1 (435 ft (132 m) above MHW 
and 960 ft (292 m) below MHW) requiring 256 36-inch steel interlocked 
pipe piles (135 on west side; 121 on east side) and approximately 1,354 
ft (451 m) in length for Portal Island No. 2 (446 ft (136 m) above MHW 
and 908 ft below (277 m) MHW) requiring 244 piles of the same size and 
type (129 piles on west side; 115 on east side). Both berms will extend 
channelward from each portal island. Construction methods will include 
impact pile driving as well as casing advancement by DTH hammer. 
Interlocked pipe piles will be installed through the use of DTH 
drilling equipment. This equipment uses reverse circulation drilling 
techniques in order to advance hollow steel pipes through the existing 
rock found within the project site. Reverse circulation drilling is a 
process that involves the use of compressed air to power a down-the-
hole hammer drill. In addition to providing the reciprocating action of 
the drill, the compressed air also serves to lift the drill cuttings 
away from the face of the drill and direct them back into the drill 
string where they are collected from the drill system for disposal. 
Once the pipes are advanced through the rock layer using the DTH 
technology, they are driven to final grade via traditional impact 
driving methods.
     Vibratory installation and removal of 12 36-inch steel 
pipe piles at Portal Island 1 and 16 piles at Portal Island 2 on both 
sides of the new tunnel alignment for settlement mitigation, support of 
excavation (SOE), and to facilitate flowable fill placement.
     Some in-water construction activities would occur 
simultaneously. Table 2 depicts concurrent driving scenarios (i.e., 
Impact + DTH; DTH + DTH) and the number of days they are anticipated to 
occur at specific locations (i.e. Portal Island 1; Portal Island 2; 
Portal Island 1 and Portal Island 2).

                                            Table 1--Pile Driving Activities Associated With the PTST Project
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                     Number of   Days per
Pile  location      Pile function            Pile type         Installation/removal      Bubble        piles     activity  Days per activity  (by hammer
                                                                      method             curtain     below MHW   (total)               type)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.............  Mooring dolphins.....  12-inch Timber piles.  Vibratory (Install)..  No............        120         21  12 Days (10 Piles/Day).
                                                              Impact (if needed)...  No............                        3 Days (12 Piles/Day).
                                                              Vibratory (Removal)..  No............                        6 Days (20 Piles/Day).
1.............  Temporary Dock.......  42-inch Diameter       DTH (install)........  No............         58         48  29 Days (2 Piles/day).
                                        Steel Pipe Casing.    Vibratory (removal)..  No............                        19 Days (3 Piles/day).
                                       36-inch Diameter       Impact...............  Yes...........       * 58         29  29 Days (2 Piles/day).
                                        Steel Pipe Pile.
1.............  Omega Trestle........  36-inch Diameter       DTH (Install)........  No............      ** 36         78  13 Days (2 Piles/Day).
                                        Steel Pipe Piles.
                                                              Impact...............  Yes...........                        65 Days (0.4 Piles/Day).
1.............  Berm Support of        36-inch Diameter       DTH (install)........  No............        135         58  45 Days (3 Piles/Day).
                 Excavation Wall--      Steel Interlocked
                 West Side.             Pipe Piles.
                                                              Impact...............  Yes...........                        13 Days (10 Piles/Day).
1.............  Berm Support of        36-inch Diameter       DTH (Install)........  No............        121        121  80 Days (1.5 Piles/Day).
                 Excavation Wall--      Steel Interlocked
                 East Side.             Pipe Piles.
                                                              Impact...............  Yes...........                        41 Days (3 Piles/Day).
1.............  Mooring Piles and      36-inch Diameter       Vibratory (Install &   No............         12          2  2 Days (12 Piles/Day).
                 Templates.             Steel Pipe Piles.      Removal).
2.............  Mooring Dolphins.....  12-inch Timber Piles.  Vibratory (Install)..  No............         60         12  6 Days (10 Piles/Day).
                                                              Impact (if needed)...  No............                        2 Days (15 Piles/Day).***
                                                              Vibratory (Removal)..  No............                        4 Days (20 Piles/Day).
2.............  Omega Trestle........  36-inch Diameter       DTH (Install)........  No............         28         28  16 Days (2 Piles/Day).
                                        Steel Pipe Piles.
                                                              Impact...............  Yes...........                        12 Days (2.33 Piles/Day).
2.............  Berm Support of        36-inch Diameter       DTH (Install)........  No............        129         55  42 Days (3 Piles/Day).
                 Excavation Wall--      Steel Interlocked
                 West Side.             Pipe Piles.
                                                              Impact...............  Yes...........                        13 Days (9.5 Piles/Day).
2.............  Berm Support of        36-inch Diameter       DTH (Install)........  No............        115        106  71 Days (1.5 Piles/Day).
                 Excavation Wall--      Steel Interlocked
                 East Side.             Pipe Piles.
                                                              Impact...............  Yes...........                        35 Days (3 Piles/Day).
2.............  Mooring Piles and      36-inch Diameter       Vibratory (Install &   No............         16          4  4 Days (4 Piles/Day).
                 Templates.             Steel Pipe Piles.      Removal).
                                                                                                    -----------
    Total.....  .....................  .....................  .....................  ..............        878
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* 11 piles will be installed in <10 ft water so bubble curtain will not be used.
** 10 piles will be installed in <10 ft water so bubble curtain will not be used.


                             Table 2--Concurrent Driving Scenarios for PTST Project
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                                                                              Number of days
                                                        --------------------------------------------------------
              Concurrent driving scenarios                                                     Driving at Portal
                                                              Island 1           Island 2         Island 1 and
                                                                                               Portal Island 2 *
----------------------------------------------------------------------------------------------------------------
Impact + DTH...........................................                 13                 14                 13
DTH + DTH..............................................                 22                 11                 17
----------------------------------------------------------------------------------------------------------------
* Single hammer at each portal island.

    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. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 3 lists all species with expected potential for occurrence 
near the project area and summarizes information related to the 
population or stock, including regulatory status under the

[[Page 64851]]

MMPA and ESA and potential biological removal (PBR), where known. For 
taxonomy, we follow Committee on Taxonomy (2018). PBR is defined by the 
MMPA as the maximum number of animals, not including natural 
mortalities, that may be removed from a marine mammal stock while 
allowing that stock to reach or maintain its optimum sustainable 
population (as described in NMFS's SARs). While no mortality is 
anticipated or authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's United States Atlantic and Gulf of Mexico Marine Mammal Stock 
Assessments (Hayes et al. 2019). All values presented in Table 3 are 
the most recent available at the time of publication and are available 
in the 2018 SARs (Hayes et al. 2019).

                                          Table 3--Marine Mammal Species Likely To Occur Near the Project Area
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                                                                                         ESA/MMPA status;    Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
    North Atlantic right whale \7\..  Eubalaena glacialis....  Western North Atlantic   E, D; Y             451 (0, 411 \4\; 2017)        0.9       5.56
                                                                (WNA).
Family Balaenopteridae (rorquals):
    Humpback whale \5\..............  Megaptera novaeangliae.  Gulf of Maine..........  -,-; N              896 (.42; 896; 2012)..       14.6        9.7
    Fin whale \7\...................  Balaenoptera physalus..  WNA....................  E,D; Y              1,618 (0.33; 1,234;           2.5        2.5
                                                                                                             2011.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Bottlenose dolphin..............  Tursiops truncatus.....  WNA Coastal, Northern    -,-; Y              6,639 (0.41; 4,759;            48   6.1-13.2
                                                                Migratory.                                   2011).
                                                               WNA Coastal, Southern    -,-; Y              7,751 (0.06; 2,353;            23     0-14.3
                                                                Migratory.                                   2011).
                                                               Northern North Carolina  -,-; Y              823 (0.06; 782; 2013).        7.8   0.8-18.2
                                                                Estuarine System.
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Gulf of Maine/Bay of     -, -; N             79,833 (0.32; 61,415;         706        256
                                                                Fundy.                                       2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  WNA....................  -; N                75,834 (0.1; 66,884,        2,006        345
                                                                                                             2012).
    Gray seal \6\...................  Halichoerus grypus.....  WNA....................  -; N                27,131 (0.19, 23,158,       1,359      5,688
                                                                                                             2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ For the North Atlantic right whale the best available abundance estimate is derived from the 2018 North Atlantic Right Whale Consortium 2018 Annual
  Report Card (Pettis et al. 2018).
\5\ 2018 U.S. Atlantic SAR for the Gulf of Maine feeding population lists a current abundance estimate of 896 individuals. However, we note that the
  estimate is defined on the basis of feeding location alone (i.e., Gulf of Maine) and is therefore likely an underestimate.
\6\ The NMFS stock abundance estimate applies to U.S. population only, however the actual stock abundance is approximately 505,000.
\7\ Species are not expected to be taken or proposed for authorization.

    All species that could potentially occur in the proposed survey 
areas are included in Table 3. However, the temporal and/or spatial 
occurrence of North Atlantic right whale and fin whale is such that 
take is not expected to occur, and they are not discussed further 
beyond the explanation provided here. Between 1998 and 2013, there were 
no reports of North Atlantic right whale strandings within the 
Chesapeake Bay and only four reported standings along the coast of 
Virginia. During this same period, only six fin whale strandings were 
recorded within the Chesapeake Bay (Barco and Swingle 2014). There were 
no reports of fin whale strandings (Swingle et al. 2017) in 2016. Due 
to the low occurrence of North Atlantic right whales and fin whales, 
NMFS is not proposing to authorize take of these species. There are 
also few reported sightings or observations of either species in the 
Bay. Since June 7, 2017, elevated North Atlantic right whale 
mortalities have been documented, primarily in Canada, and were 
declared an Unusual Mortality Event (UME). As of September 30, 2019, 
only a single right whale mortality has been documented this year, 
which occurred offshore of Virginia Beach, VA and was caused by chronic

[[Page 64852]]

entanglement. Due to the low occurrence of North Atlantic right whales 
and fin whales, NMFS is not proposing to authorize take of these 
species.

Cetaceans

Humpback Whale
    The humpback whale is found worldwide in all oceans. Humpbacks 
occur off southern New England in all four seasons, with peak abundance 
in spring and summer. In winter, humpback whales from waters off New 
England, Canada, Greenland, Iceland, and Norway migrate to mate and 
calve primarily in the West Indies (including the Antilles, the 
Dominican Republic, the Virgin Islands and Puerto Rico), where spatial 
and genetic mixing among these groups occurs.
    For the humpback whale, NMFS defines a stock on the basis of 
feeding location, i.e., Gulf of Maine. However, our reference to 
humpback whales in this document refers to any individuals of the 
species that are found in the specific geographic region. These 
individuals may be from the same breeding population (e.g., West Indies 
breeding population of humpback whales) but visit different feeding 
areas.
    Based on photo-identification only 39 percent of individual 
humpback whales observed along the mid- and south Atlantic U.S. coast 
are from the Gulf of Maine stock (Barco et al., 2002). Therefore, the 
SAR abundance estimate underrepresents the relevant population, i.e., 
the West Indies breeding population.
    Prior to 2016, humpback whales were listed under the ESA as an 
endangered species worldwide. Following a 2015 global status review 
(Bettridge et al., 2015), NMFS established 14 DPSs with different 
listing statuses (81 FR 62259; September 8, 2016) pursuant to the ESA. 
The West Indies DPS, which consists of the whales whose breeding range 
includes the Atlantic margin of the Antilles from Cuba to northern 
Venezuela, and whose feeding range primarily includes the Gulf of 
Maine, eastern Canada, and western Greenland, was delisted. As 
described in Bettridge et al. (2015), the West Indies DPS has a 
substantial population size (i.e., approximately 10,000; Stevick et 
al., 2003; Smith et al., 1999; Bettridge et al., 2015), and appears to 
be experiencing consistent growth. Humpback whales are the only large 
cetaceans that are likely to occur in the project area and could be 
found there at any time of the year. There have been 33 humpback whale 
strandings recorded in Virginia between 1988 and 2013. Most of these 
strandings were reported from ocean facing beaches, but 11 were also 
within the Chesapeake Bay (Barco and Swingle 2014). Strandings occurred 
in all seasons, but were most common in the spring.
    Since January 2016, elevated humpback whale mortalities have 
occurred along the Atlantic coast from Maine through Florida. The event 
has been declared a UME with 105 strandings recorded, 7 of which 
occurred in or near the mouth of the Chesapeake Bay. Partial or full 
necropsy examinations have been conducted on approximately half of the 
known cases. A portion of the whales have shown evidence of pre-mortem 
vessel strike; however, this finding is not consistent across all of 
the whales examined so more research is needed. NOAA is consulting with 
researchers that are conducting studies on the humpback whale 
populations, and these efforts may provide information on changes in 
whale distribution and habitat use that could provide additional 
insight into how these vessel interactions occurred. More detailed 
information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2019-humpback-whale-unusual-mortality-event-along-atlantic-coast. Three previous UMEs involving humpback whales 
have occurred since 2000, in 2003, 2005, and 2006.
    Humpback whales use the mid-Atlantic as a migratory pathway to and 
from the calving/mating grounds, but it may also be an important winter 
feeding area for juveniles. Since 1989, observations of juvenile 
humpbacks in the mid-Atlantic have been increasing during the winter 
months, peaking from January through March (Swingle et al. 1993). 
Biologists theorize that non-reproductive animals may be establishing a 
winter feeding range in the mid-Atlantic since they are not 
participating in reproductive behavior in the Caribbean. Swingle et al. 
(1993) identified a shift in distribution of juvenile humpback whales 
in the nearshore waters of Virginia, primarily in winter months. 
Identified whales using the mid-Atlantic area were found to be 
residents of the Gulf of Maine and Atlantic Canada (Gulf of St. 
Lawrence and Newfoundland) feeding groups; suggesting a mixing of 
different feeding populations in the Mid-Atlantic region.
Bottlenose Dolphin
    The bottlenose dolphin occurs in temperate and tropical oceans 
throughout the world, ranging in latitudes from 45[deg] N to 45[deg] S 
(Blaylock 1985). In the western Atlantic Ocean there are two distinct 
morphotypes of bottlenose dolphins, an offshore type that occurs along 
the edge of the continental shelf as well as an inshore type. The 
inshore morphotype can be found along the entire United States coast 
from New York to the Gulf of Mexico, and typically occurs in waters 
less than 20 meters deep (NOAA Fisheries 2016a). Bottlenose dolphins 
found in Virginia are representative primarily of either the northern 
migratory coastal stock, southern migratory coastal stock, or the 
Northern North Carolina Estuarine System Stock (NNCES).
    The northern migratory coastal stock is best defined by its 
distribution during warm water months when the stock occupies coastal 
waters from the shoreline to approximately the 20-m isobath between 
Assateague, Virginia, and Long Island, New York (Garrison et al. 
2017b). The stock migrates in late summer and fall and, during cold 
water months (best described by January and February), occupies coastal 
waters from approximately Cape Lookout, North Carolina, to the North 
Carolina/Virginia border (Garrison et al. 2017b). Historically, common 
bottlenose dolphins have been rarely observed during cold water months 
in coastal waters north of the North Carolina/Virginia border, and 
their northern distribution in winter appears to be limited by water 
temperatures. Overlap with the southern migratory coastal stock in 
coastal waters of northern North Carolina and Virginia is possible 
during spring and fall migratory periods, but the degree of overlap is 
unknown and it may vary depending on annual water temperature (Garrison 
et al. 2016). When the stock has migrated in cold water months to 
coastal waters from just north of Cape Hatteras, North Carolina, to 
just south of Cape Lookout, North Carolina, it overlaps spatially with 
the Northern North Carolina Estuarine System (NNCES) Stock (Garrison et 
al. 2017b).
    The southern migratory coastal stock migrates seasonally along the 
coast between North Carolina and northern Florida (Garrison et al. 
2017b). During January-March, the southern migratory coastal stock 
appears to move as far south as northern Florida. During April-June, 
the stock moves back north past Cape Hatteras, North Carolina (Garrison 
et al. 2017b), where it overlaps, in coastal waters, with the NNCES 
stock (in waters <=1 km from shore). During the warm water months of 
July-August, the stock is presumed to occupy coastal waters north of 
Cape Lookout, North Carolina, to Assateague, Virginia, including the 
Chesapeake Bay.

[[Page 64853]]

    The NNCES stock is best defined as animals that occupy primarily 
waters of the Pamlico Sound estuarine system (which also includes Core, 
Roanoke, and Albemarle sounds, and the Neuse River) during warm water 
months (July-August). Members of this stock also use coastal waters 
(<=1 km from shore) of North Carolina from Beaufort north to Virginia 
Beach, Virginia, including the lower Chesapeake Bay. A community of 
NNCES dolphins are likely year-round Bay residents (Patterson, Pers. 
Comm).
Harbor Porpoise
    The harbor porpoise is typically found in colder waters in the 
northern hemisphere. In the western North Atlantic Ocean, harbor 
porpoises range from Greenland to as far south as North Carolina (Barco 
and Swingle 2014). They are commonly found in bays, estuaries, and 
harbors less than 200 meters deep (NOAA Fisheries 2017c). Harbor 
porpoises in the United States are made up of the Gulf of Main/Bay of 
Fundy stock. Gulf of Main/Bay of Fundy stock are concentrated in the 
Gulf of Maine in the summer, but are widely dispersed from Maine to New 
Jersey in the winter. South of New Jersey, harbor porpoises occur at 
lower densities. Migrations to and from the Gulf of Maine do not follow 
a defined route. (NOAA Fisheries 2016c).
    Harbor porpoise occur seasonally in the winter and spring in small 
numbers. Strandings occur primarily on ocean facing beaches, but they 
occasionally travel into the Chesapeake Bay to forage and could occur 
in the project area (Barco and Swingle 2014). Since 1999, stranding 
incidents have ranged widely from a high of 40 in 1999 to 2 in 2011, 
2012, and 2016 (Barco et al. 2017).

Pinnipeds

Harbor Seal
    The harbor seal occurs in arctic and temperate coastal waters 
throughout the northern hemisphere, including on both the east and west 
coasts of the United States. On the east coast, harbor seals can be 
found from the Canadian Arctic down to Georgia (Blaylock 1985). Harbor 
seals occur year-round in Canada and Maine and seasonally (September-
May) from southern New England to New Jersey (NOAA Fisheries 2016d). 
The range of harbor seals appears to be shifting as they are regularly 
reported further south than they were historically. In recent years, 
they have established haul out sites in the Chesapeake Bay including on 
the portal islands of the CBBT (Rees et al. 2016, Jones et al. 2018).
    Harbor seals are the most common seal in Virginia (Barco and 
Swingle 2014). They can be seen resting on the rocks around the portal 
islands of the CBBT from December through April. Seal observation 
surveys conducted at the CBBT recorded 112 seals during the 2014/2015 
season, 184 seals during the 2015/2016 season, 308 seals in the 2016/
2017 season and 340 seals during the 2017/2018 season. They are 
primarily concentrated north of the project area at Portal Island No. 3 
(Rees et al 2016; Jones et al. 2018).
Gray Seal
    The gray seal occurs on both coasts of the Northern Atlantic Ocean 
and are divided into three major populations (NOAA Fisheries 2016b). 
The western north Atlantic stock occurs in eastern Canada and the 
northeastern United States, occasionally as far south as North 
Carolina. Gray seals inhabit rocky coasts and islands, sandbars, ice 
shelves and icebergs (NOAA Fisheries 2016b). In the United States, gray 
seals congregate in the summer to give birth at four established 
colonies in Massachusetts and Maine (NOAA Fisheries 2016b). From 
September through May, they disperse and can be abundant as far south 
as New Jersey. The range of gray seals appears to be shifting as they 
are regularly being reported further south than they were historically 
(Rees et al. 2016).
    Gray seals are uncommon in Virginia and the Chesapeake Bay. Only 15 
gray seal strandings were documented in Virginia from 1988 through 2013 
(Barco and Swingle 2014). They are rarely found resting on the rocks 
around the portal islands of the CBBT from December through April 
alongside harbor seals. Seal observation surveys conducted at the CBBT 
recorded one gray seal in each of the 2014/2015 and 2015/2016 seasons 
while no gray seals were reported during the 2016/2017 and 2017/2018 
seasons (Rees et al. 2016, Jones et al. 2018).

Habitat

    No ESA-designated critical habitat overlaps with the project area. 
A migratory Biologically Important Area (BIA) for North Atlantic right 
whales is found offshore of the mouth of the Chesapeake Bay but does 
not overlap with the project area. As previously described, right 
whales are rarely observed in the Bay and sound from the proposed in-
water activities are not anticipated to propagate outside of the Bay to 
the boundary of the designated BIA.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et al. 
1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
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 4.

                  Table 4--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).

[[Page 64854]]

 
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. 
Five marine mammal species (3 cetacean and 2 phocid pinniped) have the 
reasonable potential to co-occur with the proposed survey activities. 
Please refer to Table 3. Of the cetacean species that may be present, 
one is classified as low-frequency (humpback whale), one is classified 
as mid-frequency (bottlenose dolphin) and one is classified as high-
frequency (harbor porpoise).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take by Incidental Harassment 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 by Incidental Harassment 
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 on 
individuals are likely to impact marine mammal species or stocks.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far. The sound level of an area is defined by the 
total acoustical energy being generated by known and unknown sources. 
These sources may include physical (e.g., waves, wind, precipitation, 
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced 
by marine mammals, fish, and invertebrates), and anthropogenic sound 
(e.g., vessels, dredging, aircraft, construction).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al. 1995). The result is that, depending 
on the source type and its intensity, sound from the specified activity 
may be a negligible addition to the local environment or could form a 
distinctive signal that may affect marine mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving, vibratory pile 
removal, and drilling with a DTH hammer. The sounds produced by these 
activities fall into one of two general sound types: Impulsive and non-
impulsive. Impulsive sounds (e.g., explosions, gunshots, sonic booms, 
impact pile driving) are typically transient, brief (less than 1 
second), broadband, and consist of high peak sound pressure with rapid 
rise time and rapid decay (ANSI 1986; NIOSH 1998; NMFS 2018). Non-
impulsive sounds (e.g. aircraft, machinery operations such as drilling 
or dredging, vibratory pile driving, and active sonar systems) can be 
broadband, narrowband or tonal, brief or prolonged (continuous or 
intermittent), and typically do not have the high peak sound pressure 
with raid rise/decay time that impulsive sounds do (ANSI 1995; NIOSH 
1998; NMFS 2018). The distinction between these two sound types is 
important because they have differing potential to cause physical 
effects, particularly with regard to hearing (e.g., Ward 1997 in 
Southall et al. 2007).
    Impact hammers operate by repeatedly dropping 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). A DTH hammer is used to place hollow steel piles or casings by 
drilling. A DTH hammer is a drill bit that drills through the bedrock 
using a pulse mechanism that functions at the bottom of the hole. This 
pulsing bit breaks up rock to allow removal of debris and insertion of 
the pile. The head extends so that the drilling takes place below the 
pile. Sound associated with DTH has both continuous and impulsive 
characteristics and may be appropriately characterized one way or the 
other depending on the operating parameters and settings that are 
utilized on a specific device. CTJV conducted sound

[[Page 64855]]

source verification (SSV) monitoring prior to the expiration of the 
previous IHA and determined that impulsive characteristics were 
predominant as the equipment was employed at the PTST project location 
(Denes et al. 2019).
    The likely or possible impacts of CTJV'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.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving is the primary means by which marine 
mammals may be harassed from CTJV'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). Exposure to in-water construction noise 
has the potential to result in auditory threshold shifts and behavioral 
reactions (e.g., avoidance, temporary cessation of foraging and 
vocalizing, changes in dive behavior) and/or lead to non-observable 
physiological responses such an increase in stress hormones 
((Richardson et al. 1995; Gordon et al. 2004; Nowacek et al.2007; 
Southall et al. 2007; Gotz et al. 2009). 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). Here we discuss physical auditory effects 
(threshold shifts), followed by behavioral effects and potential 
impacts on habitat.
    Richardson et al. (1995) described zones of increasing intensity of 
effect that might be expected to occur, in relation to distance from a 
source and assuming that the signal is within an animal's hearing 
range. First is the area within which the acoustic signal would be 
audible (potentially perceived) to the animal, but not strong enough to 
elicit any overt behavioral or physiological response. The next zone 
corresponds with the area where the signal is audible to the animal and 
of sufficient intensity to elicit behavioral or physiological 
responsiveness. Third is a zone within which, for signals of high 
intensity, the received level is sufficient to potentially cause 
discomfort or tissue damage to auditory or other systems. Overlaying 
these zones to a certain extent is the area within which masking (i.e., 
when a sound interferes with or masks the ability of an animal to 
detect a signal of interest that is above the absolute hearing 
threshold) may occur; the masking zone may be highly variable in size.
    We describe the more severe effects (i.e., permanent hearing 
impairment, certain non-auditory physical or physiological effects) 
only briefly as we do not expect that there is a reasonable likelihood 
that CTJV's activities would result in such effects (see below for 
further discussion). 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. 2014b), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS 2018). Available data from 
humans and other terrestrial mammals indicate that a 40 dB threshold 
shift approximates PTS onset (see Ward et al. 1958, 1959; Ward 1960; 
Kryter et al. 1966; Miller 1974; Ahroon et al. 1996; Henderson et al. 
2008). PTS levels for marine mammals are estimates, 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 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 (2016), 
marine mammal studies have shown the amount of TTS increases with 
cumulative sound exposure level (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.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale (Delphinapterus

[[Page 64856]]

leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and five species of pinnipeds exposed to a limited 
number of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (Finneran 2015). TTS was not observed in trained 
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to 
impulsive noise at levels matching previous predictions of TTS onset 
(Reichmuth et al. 2016). In general, harbor seals and harbor porpoises 
have a lower TTS onset than other measured pinniped or cetacean species 
(Finneran 2015). Additionally, the existing marine mammal TTS data come 
from a limited number of individuals within these species. No data are 
available on noise-induced hearing loss for mysticetes. For summaries 
of data on TTS in marine mammals or for further discussion of TTS onset 
thresholds, please see Southall et al. (2007), Finneran and Jenkins 
(2012), Finneran (2015), and Table 5 in NMFS (2018).
    Behavioral Harassment--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, number of blows per surfacing, or moving 
direction and/or speed; reduced/increased vocal activities; changing/
cessation of certain behavioral activities (such as socializing or 
feeding); visible startle response or aggressive behavior (such as 
tail/fluke slapping or jaw clapping); avoidance of areas where sound 
sources are located. Pinnipeds may increase their haul out time, 
possibly to avoid in-water disturbance (Thorson and Reyff 2006). 
Behavioral responses to sound are highly variable and context-specific 
and any reactions depend on numerous intrinsic and extrinsic factors 
(e.g., species, state of maturity, experience, current activity, 
reproductive state, auditory sensitivity, time of day), as well as the 
interplay between factors (e.g., Richardson et al. 1995; Wartzok et al. 
2003; Southall et al. 2007; Weilgart 2007; Archer et al. 2010). 
Behavioral reactions can vary not only among individuals but also 
within an individual, depending on previous experience with a sound 
source, context, and numerous other factors (Ellison et al. 2012), and 
can vary depending on characteristics associated with the sound source 
(e.g., whether it is moving or stationary, number of sources, distance 
from the source). In general, pinnipeds seem more tolerant of, or at 
least habituate more quickly to, potentially disturbing underwater 
sound than do cetaceans, and generally seem to be less responsive to 
exposure to industrial sound than most cetaceans. Please see Appendices 
B-C of Southall et al. (2007) for a review of studies involving marine 
mammal behavioral responses to sound.
    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. 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

[[Page 64857]]

determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al. 2001, 2005b, 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 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, 2007b). 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). 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 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 five-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

[[Page 64858]]

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).
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al. 1995). Masking occurs when 
the receipt of a sound is interfered with by another coincident sound 
at similar frequencies and at similar or higher intensity, and may 
occur whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions.
    Masking of natural sounds can result when human activities produce 
high levels of background sound at frequencies important to marine 
mammals. Conversely, if the background level of underwater sound is 
high (e.g. on a day with strong wind and high waves), an anthropogenic 
sound source would not be detectable as far away as would be possible 
under quieter conditions and would itself be masked. Busy ship channels 
traverse Thimble Shoal. Commercial vessels including container ships 
and cruise ships as well as numerous recreational frequent the area, so 
background sound levels near the PTST project area are likely to be 
elevated, although to what degree is unknown.
    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. 2007b; 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).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.

Underwater Acoustic Effects

Potential Effects of Pile Driving Sound
    The effects of sounds from pile driving might include one or more 
of the following: Temporary or permanent hearing impairment, non-
auditory physical or physiological effects, behavioral disturbance, and 
masking (Richardson et al. 1995; Gordon et al. 2003; Nowacek et al. 
2007; Southall et al. 2007). The effects of pile driving on marine 
mammals are dependent on several factors, including the type and depth 
of the animal; the pile size and type, and the intensity and duration 
of the pile driving sound; the substrate; the standoff distance between 
the pile and the animal; and the sound propagation properties of the 
environment. Impacts to marine mammals from pile driving activities are 
expected to result primarily from acoustic pathways. As such, the 
degree of effect is intrinsically related to the frequency, received 
level, and duration of the sound exposure, which are in turn influenced 
by the distance between the animal and the source. The further away 
from the source, the less intense the exposure should be. The substrate 
and depth of the habitat affect the sound propagation properties of the 
environment. In addition, substrates that are soft (e.g., sand) would 
absorb or attenuate the sound more readily than hard substrates (e.g., 
rock), which may reflect the acoustic wave. Soft porous substrates 
would also likely require less time to drive the pile, and possibly 
less forceful equipment, which would ultimately decrease the intensity 
of the acoustic source.
    In the absence of mitigation, impacts to marine species could be 
expected to include physiological and behavioral responses to the 
acoustic signature (Viada et al. 2008). Potential effects from 
impulsive sound sources like impact pile driving can range in severity 
from effects such as behavioral disturbance to temporary or permanent 
hearing impairment (Yelverton et al. 1973). Due to the nature of the 
pile driving sounds in the project, behavioral disturbance is the most 
likely effect from the proposed activity. Marine mammals exposed to 
high intensity sound repeatedly or for prolonged periods can experience 
hearing threshold shifts. Note that PTS constitutes injury, but TTS 
does not (Southall et al. 2007).
Non-Auditory Physiological Effects
    Non-auditory physiological effects or injuries that theoretically 
might occur in marine mammals exposed to strong underwater sound 
include stress, neurological effects, bubble formation, resonance 
effects, and other types of organ or tissue damage (Cox et al. 2006; 
Southall et al. 2007). Studies examining such effects are limited. In 
general, little is known about the potential for pile driving to cause 
non-auditory physical effects in marine mammals. Available data suggest 
that such effects, if they occur at all, would presumably be limited to 
short distances from the sound source and to activities that extend 
over a prolonged period. The available data do not allow identification 
of a specific exposure level above which non-auditory effects can be 
expected (Southall et al. 2007) or any meaningful quantitative 
predictions of the numbers (if any) of marine mammals that might be 
affected in those ways. We do not expect any non-auditory physiological 
effects because of mitigation that prevents animals from approach the 
source too closely. Marine mammals that show behavioral avoidance of 
pile driving, including some odontocetes and some pinnipeds,

[[Page 64859]]

are especially unlikely to incur non-auditory physical effects.
Disturbance Reactions
    Responses to continuous sound, such as vibratory pile installation, 
have not been documented as well as responses to pulsed sounds. With 
both types of pile driving, it is likely that the onset of pile driving 
could result in temporary, short term changes in an animal's typical 
behavior and/or avoidance of the affected area. These behavioral 
changes may include (Richardson et al. 1995): Changing durations of 
surfacing and dives, number of blows per surfacing, or moving direction 
and/or speed; reduced/increased vocal activities; changing/cessation of 
certain behavioral activities (such as socializing or feeding); visible 
startle response or aggressive behavior (such as tail/fluke slapping or 
jaw clapping); avoidance of areas where sound sources are located; and/
or flight responses (e.g., pinnipeds flushing into water from haul-outs 
or rookeries). Pinnipeds may increase their haul out time, possibly to 
avoid in-water disturbance (Thorson and Reyff 2006). If a marine mammal 
responds to a stimulus by changing its behavior (e.g., through 
relatively minor changes in locomotion direction/speed or vocalization 
behavior), the response may or may not constitute taking at the 
individual level, and is unlikely to affect the stock or the species as 
a whole. However, if a sound source displaces marine mammals from an 
important feeding or breeding area for a prolonged period, impacts on 
animals, and if so potentially on the stock or species, could 
potentially be significant (e.g., Lusseau and Bejder 2007; Weilgart 
2007).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, or reproduction. Significant 
behavioral modifications that could potentially lead to effects on 
growth, survival, or reproduction include:
     Drastic changes in diving/surfacing patterns (such as 
those thought to cause beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Longer-term habitat abandonment due to loss of desirable 
acoustic environment; and
     Longer-term cessation of feeding or social interaction.
    The onset of behavioral disturbance from anthropogenic sound 
depends on both external factors (characteristics of sound sources and 
their paths) and the specific characteristics of the receiving animals 
(hearing, motivation, experience, demography) and is difficult to 
predict (Southall et al. 2007).
Auditory Masking
    Natural and artificial sounds can disrupt behavior by masking. The 
frequency range of the potentially masking sound is important in 
determining any potential behavioral impacts. Because sound generated 
from in-water pile driving is mostly concentrated at low frequency 
ranges, it may have less effect on high frequency echolocation sounds 
made by porpoises. The most intense underwater sounds in the proposed 
action are those produced by impact pile driving. Given that the energy 
distribution of pile driving covers a broad frequency spectrum, sound 
from these sources would likely be within the audible range of marine 
mammals present in the project area. Impact pile driving and DTH 
drilling activities are relatively short-term, with rapid pulses 
occurring for less than fifteen minutes per pile. The probability for 
impact pile driving and DTH drilling resulting from this proposed 
action masking acoustic signals important to the behavior and survival 
of marine mammal species is low. Vibratory pile driving is also 
relatively short-term, with rapid oscillations occurring for 
approximately 30 minutes per pile. It is possible that vibratory pile 
driving resulting from this proposed action may mask acoustic signals 
important to the behavior and survival of marine mammal species, but 
the short-term duration and limited affected area would result in 
insignificant impacts from masking. Any masking event that could 
possibly rise to Level B harassment under the MMPA would occur 
concurrently within the zones of behavioral harassment already 
estimated for vibratory and impact pile driving, and which have already 
been taken into account in the exposure analysis. Active pile driving 
is anticipated to occur for up to 8 hours per day for 188 days, but we 
do not anticipate masking to significantly affect marine mammals for 
the reasons listed above.

Airborne Acoustic Effects

    Pinnipeds that occur near the project site could be exposed to 
airborne sounds associated with pile driving that have the potential to 
cause behavioral harassment, depending on their distance from pile 
driving activities. Cetaceans are not expected to be exposed to 
airborne sounds that would result in harassment as defined under the 
MMPA.
    Airborne noise would primarily be an issue for pinnipeds that are 
swimming or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. Only limited numbers of 
pinnipeds have used Portal Island 1 and 2 as haulouts (<6 percent of 
total pinniped sightings). The majority of hauled out pinniped 
sightings have been found at Portal Island 3 (~90 percent) according to 
Jones et al. (2018), which is 6 km north of Portal Island 2. This is 
far beyond the distance at which harassment could occur due to airborne 
noise.
    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 would already accounted for in these 
estimates of potential take. Therefore, we do not believe that 
authorization of incidental take resulting from airborne sound for 
pinnipeds is warranted, and airborne sound is not discussed further 
here.

Marine Mammal Habitat Effects

    The area likely impacted by the project is relatively small 
compared to the available habitat for all impacted species and stocks, 
and does not include any ESA-designated critical habitat. As previously 
mentioned, no BIAs overlap with the project area. CTJV's proposed 
construction activities would not result in permanent negative impacts 
to habitats used directly by marine mammals, but could have localized, 
temporary impacts on marine mammal habitat including their prey by 
increasing underwater and airborne SPLs 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 pile 
driving, elevated levels of underwater noise would ensonify areas

[[Page 64860]]

near the project where both fish and mammals occur and could affect 
foraging success.
    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. Therefore, the main 
impact issue associated with the proposed activity would be temporarily 
elevated sound levels and the associated direct effects on marine 
mammals, as discussed previously in this document. The primary 
potential acoustic impacts to marine mammal habitat are associated with 
elevated sound levels produced by impact, vibratory, and DTH pile 
installation as well as vibratory pile removal in the project area. 
Physical impacts to the environment such as construction debris are 
unlikely.
    In-water pile driving would also cause short-term effects on water 
quality due to increased turbidity. CTJV would employ standard 
construction best management practices to reducing any potential 
impacts. Therefore, the impact from increased turbidity levels is 
expected to be discountable.
In-Water Construction Effects on Potential Foraging Habitat
    Pile installation 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 25-foot (7.6 m) radius around the pile (Everitt et 
al. 1980). Large cetaceans are not expected to be close enough to the 
project activity areas to experience effects of turbidity, and any 
small cetaceans and pinnipeds could avoid localized areas of turbidity. 
Therefore, the impact from increased turbidity levels is expected to be 
discountable to marine mammals.
    Essential Fish Habitat (EFH) for several species or groups of 
species overlaps with the project area including: Little skate, 
Atlantic herring, red hake, windowpane flounder, winter skate, 
clearnose skate, sandbar shark, sand tiger shark, bluefish, Atlantic 
butterfish, scup, summer flounder, and black sea bass. Use of soft 
start procedure and bubble curtains will reduce the impacts of 
underwater acoustic noise to fish from pile driving activities. 
Avoidance by potential prey (i.e., fish) of the immediate area due to 
the temporary loss of this foraging habitat is also possible. The 
duration of fish avoidance of this area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity.
    In-water Construction Effects on Potential Prey (Fish)--
Construction activities would produce continuous (i.e., vibratory pile 
driving and removal) and pulsed (i.e., impact driving, DTH) sounds. 
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 (summarized in 
Popper and Hastings 2009). Hastings and Popper (2005) reviewed several 
studies that suggest fish may relocate to avoid certain areas of sound 
energy. Additional studies have documented physical and behavioral 
effects of pile driving on fish, although several are based on studies 
in support of large, multiyear bridge construction projects (e.g., 
Scholik and Yan 2001, 2002; Popper and Hastings 2009). Sound pulses at 
received levels of 160 dB may cause subtle changes in fish behavior. 
SPLs of 180 dB may cause noticeable changes in behavior (Pearson et al. 
1992; Skalski et al. 1992). SPLs of sufficient strength have been known 
to cause injury to fish and fish mortality (summarized in Popper et al. 
2014).
    The most likely impact to fish from pile driving activities at the 
project area would be temporary behavioral avoidance of the area. The 
duration of fish avoidance of this area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. In general, impacts to marine mammal prey 
species are expected to be minor and temporary.
    In summary, given the relatively small areas being affected, 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. 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 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of acoustic sources (i.e., impact driving, vibratory driving and 
removal, DTH drilling) has the potential to result in disruption of 
behavioral patterns for individual marine mammals. There is also some 
potential for auditory injury (Level A harassment) to result, primarily 
for high frequency cetacean species and phocid pinnipeds because 
predicted auditory injury zones are larger than for low-frequency and 
mid-frequency species. The proposed mitigation and monitoring measures 
are expected to minimize the severity of such taking to the extent 
practicable.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed or incur some 
degree of permanent hearing impairment; (2) the area or volume of water 
that will be ensonified above these levels in a day; (3) the density or 
occurrence of marine mammals within these ensonified areas; and, (4) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of takes, additional information that can qualitatively 
inform take estimates is also sometimes available (e.g., previous 
monitoring results or average group size). Below, we describe the 
factors considered here in more detail and present the proposed take 
estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B

[[Page 64861]]

harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al. 2007, Ellison 
et al. 2012). Based on what the available science indicates and the 
practical need to use a threshold based on a factor that is both 
predictable and measurable for most activities, NMFS uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS predicts that marine mammals are likely to 
be behaviorally harassed in a manner we consider Level B harassment 
when exposed to underwater anthropogenic noise above received levels of 
120 dB re 1 micropascal ([micro]Pa) root mean square (rms) for 
continuous (e.g., vibratory pile-driving) and above 160 dB re 1 [mu]Pa 
(rms) for non-explosive impulsive (e.g., impact pile driving) or 
intermittent (e.g., scientific sonar) sources.
    CTJV's proposed activity includes the use of continuous (vibratory 
pile driving/removal) and impulsive (impact pile driving; DTH hammer) 
sources and, therefore, the 120 and 160 dB re 1 [mu]Pa (rms) are 
applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (NMFS 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). CTJV's 
proposed activity includes the use of impulsive (impact pile driving; 
DTH drilling) and non-impulsive (vibratory pile driving) sources.
    These thresholds are provided in the Table 5 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 5--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                               PTS onset acoustic thresholds * (received level)
        Hearing Group        -----------------------------------------------------------------------------------
                                              Impulsive                               Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans  Cell 1: Lpk,flat: 219 dB; LE,LF,24h: 183  Cell 2: LE,LF,24h: 199 dB.
                               dB.
Mid-Frequency (MF) Cetaceans  Cell 3: Lpk,flat: 230 dB; LE,MF,24h: 185  Cell 4: LE,MF,24h: 198 dB.
                               dB.
High-Frequency (HF)           Cell 5: Lpk,flat: 202 dB; LE,HF,24h: 155  Cell 6: LE,HF,24h: 173 dB.
 Cetaceans.                    dB.
Phocid Pinnipeds (PW)         Cell 7: Lpk,flat: 218 dB; LE,PW,24h: 185  Cell 8: LE,PW,24h: 201 dB.
 (Underwater).                 dB.
Otariid Pinnipeds (OW)        Cell 9: Lpk,flat: 232 dB; LE,OW,24h: 203  Cell 10: LE,OW,24h: 219 dB.
 (Underwater).                 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
  has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
  National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
  incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
  ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
  generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
  the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
  be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
  it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Pile driving generates underwater noise that can potentially result in 
disturbance to marine mammals in the project area. The maximum 
(underwater) area ensonified is determined by the topography of the Bay 
including shorelines to the west south and north as well as by hard 
structures such as portal islands.
    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B * Log10 (R1/R2),

Where:

TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven 
pile, and
R2 = the distance from the driven pile of the initial 
measurement

    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive conditions including in-water structures and 
sediments. Spherical spreading occurs in a perfectly unobstructed 
(free-field) environment not limited by depth or water surface, 
resulting in a 6 dB reduction in sound level for each doubling of 
distance from the source (20*log[range]). Cylindrical spreading occurs 
in an environment in which sound propagation is bounded by the water 
surface and sea bottom, resulting

[[Page 64862]]

in a reduction of 3 dB in sound level for each doubling of distance 
from the source (10*log[range]). A practical spreading value of fifteen 
is often used under conditions, such as the PTST project site where 
water generally increases with depth as the receiver moves away from 
pile driving locations, resulting in an expected propagation 
environment that would lie between spherical and cylindrical spreading 
loss conditions. Practical spreading loss is assumed here.
    The intensity of pile driving sounds is greatly influenced by 
factors such as the type of piles, hammers, and the physical 
environment in which the activity takes place. In order to calculate 
distances to the Level A harassment and Level B harassment thresholds 
for the 36-inch steel piles proposed in this project, CTJV used 
acoustic monitoring data from other locations as described in Caltrans 
2015 for impact and vibratory driving. CTJV also conducted their own 
sound source verification testing on 42-inch steel casings as described 
below to determine source levels associated with DTH drilling. NMFS 
used vibratory driving of 36-in steel pile source levels for vibratory 
driving of 42-inch casings source levels. CTJV has proposed to employ 
bubble curtains during impact driving of 36-inch steel piles and, 
therefore, reduced the source level by 7 dB (a conservative estimate 
based on several studies including Austin et al. 2016).
    Source levels for drilling with a DTH hammer were field verified at 
the PTST project site by JASCO Applied Sciences in July 2019 (Denes, 
2019). Underwater sound levels were measured during drilling with a DTH 
hammer at five pile locations--3 without bubble curtain attenuation and 
2 with bubble curtain attenuation. The average SPL value at 10 m for 
the DTH location without a bubble curtain was 180 dB re 1[mu]Pa, while 
the average SEL and PK levels were 164 dB re 1[mu]Pa2[middot]s and 190 
dB re 1[mu]Pa, respectively. These values were greater than DTH testing 
done at another location in Alaska (Denes et al. 2016). The dominant 
signal characteristic was found to be impulsive rather than continuous. 
Southall et al. (2007) suggested that impulsive sounds can be 
distinguished from non-impulsive sounds by comparing the SPL of a 0.035 
s window that includes the pulse and with a 1 s window that may include 
multiple pulses. If the SPL of the 0.035 s window is 3 dB or more 
greater than the 1 s window, then the signal should be considered 
impulsive. Denes (2019) observed that at the PTST site, the SPL of the 
0.035 s pulse is 5 dB higher than the SPL of the 1 s sample, so the DTH 
source is classified here as impulsive. Source levels associated with 
DTH drilling of 42-inch steel casings were assumed to be the same as 
recorded for installation of 36-in steel pipe by DTH.
    CTJV utilized in-water measurements generated by the Greenbusch 
Group (2018) from the WSDOT Seattle Pier 62 project (83 FR 39709) to 
establish proxy sound source levels for vibratory installation and 
removal of 14-inch timber piles. NMFS reviewed the report by the 
Greenbusch Group (2018) and determined that the findings were derived 
by pooling together all steel pile and timber pile at various distance 
measurements data together. The data was not normalized to the standard 
10 m distance. NMFS analyzed source measurements at different distances 
for all 63 individual timber piles that were removed and normalized the 
values to 10 m. The results showed that the median is 152 dB SPLrms. 
This value was used as the source level for vibratory removal of 14-
inch timber piles. Source levels for impact driving of 12-in timber 
piles were from the Ballena Bay Marina project in Alameda, CA as 
described in Caltrans 2015. Sound source levels used to calculate take 
are shown in Table 6.

                                     Table 6--The Sound Source Levels (dB Peak, dB RMS, and dB sSEL) by Hammer Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                            Estimated
                                                         Estimated peak     Estimated     single strike
           Type of pile                 Hammer type        noise level   pressure level  sound exposure    Relevant piles at the        Pile function
                                                            (dB peak)       (dB RMS)        level (dB           PTST project
                                                                                              sSEL)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch Steel Pipe...............  Impact \a\..........             210             193             183  Plumb....................  Omega Trestle,
                                                                                                                                     Temporary Dock,
                                                                                                                                     Berm Wall West, and
                                                                                                                                     Berm Wall East.
                                   Impact with Bubble               203             186             176  Plumb....................  Berm Wall West, Berm
                                    Curtain \b\.                                                                                     Wall East, and
                                                                                                                                     Temporary Dock.
                                   DTH--Impulsive \d\..             190             180             164  Plumb....................  Omega Trestle, Berm
                                                                                                                                     Wall West, and Berm
                                                                                                                                     Wall East.
                                   Vibratory \a\.......              NA             170             170  Pipe Piles...............  Mooring Piles and
                                                                                                                                     Templates.
12-inch Timber Pile..............  Vibratory \c\.......              NA             152             152  Plumb....................  Mooring Dolphins.
                                   Impact \a\..........             177             165             157  Plumb....................  Mooring Dolphins.
42-inch Steel Casing.............  DTH--Impulsive \d\..             190             180             164  Steel Casing.............  Temporary Dock.
                                   Vibratory \a\.......              NA             170             170  Pipe Piles...............  Temporary Dock.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: sSEL = Single Strike Exposure Level; dB = decibel; N/A = not applicable.
\a\ Caltrans 2015.
\b\ 7 dB reduction was assumed for use an encased bubble curtain (Austin et al. 2016).
\c\ Greenbusch Group 2018.
\d\ Denes et al. 2019.

    CTJV used NMFS' Optional User Spreadsheet, available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance, to input project-specific parameters and 
calculate the isopleths for the Level A harassment zones for impact and 
vibratory pile driving. When the NMFS Technical Guidance (2016) was 
published, in recognition of the fact that ensonified area/volume could 
be more technically challenging to predict because of the duration 
component in the new thresholds, we developed a User Spreadsheet that 
includes tools to help predict a simple isopleth that can be used in 
conjunction with marine mammal density or occurrence to help predict 
takes. We note that because of some of the assumptions included in the 
methods used for these tools, we anticipate that isopleths produced are 
typically going to be overestimates of some degree, which may result in 
some degree of overestimate of Level A harassment take. However, these 
tools offer the best way to predict appropriate isopleths when more 
sophisticated 3D modeling methods are not available, and NMFS continues 
to develop ways to quantitatively refine these tools, and will 
qualitatively address the output where appropriate. For stationary 
source pile driving, the NMFS User Spreadsheet predicts the distance at

[[Page 64863]]

which, if a marine mammal remained at that distance the whole duration 
of the activity, it would incur PTS.
    Table 7 provides the sound source values and input used in the User 
Spreadsheet to calculate harassment isopleths for each source type 
while Table 8 shows distances to Level A harassment isopleths. Note 
that the isopleths calculated using the proposed number of piles driven 
per day is highly conservative. PTS is based on accumulated exposure 
over time. Therefore, an individual animal would have to be within the 
calculated PTS zones when all of the piles of a single type and driving 
method are being actively installed throughout an entire day. The 
marine mammals proposed for authorization are highly mobile. It is 
unlikely that an animal would remain within the PTS zone during the 
installation of, for example, 10 piles over an 8-hour period. NMFS 
opted to reduce the number of piles driven per day by approximately 50 
percent in order to derive more realistic PTS isopleths. In cases where 
the number of proposed piles per day was an odd number, NMFS used the 
next largest whole number that was greater than 50 percent. These are 
shown in Table 7 in the row with the heading ``Piles/day to calculate 
PTS.'' Table 8 contains calculated distances to PTS isopleths and Table 
9 depicts distances to Level B harassment isopleths.

                                  Table 7--User Spreadsheet Input Parameters Used for Calculating Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     12-in timber                       36-in steel                           42-in steel casing
                                                --------------------------------------------------------------------------------------------------------
                Model parameter                                                              Impact--with
                                                 Vibratory    Impact   Vibratory    Impact       bubble       DTH     Vibratory     DTH     DTH--simult.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used...........................      * A.1     ** E.1        A.1        E.1          E.1         E.1        A.1        E.1          E.1
Weighting Factor (kHz).........................        2.5          2        2.5        2.0          2.0         2.0        2.5        2.0          2.0
RMS (dB).......................................        152        165        170        193          186         180        170        180          180
Peak/SEL (dB)..................................         na    177/157         na    210/183      203/176     190/164         na    190/164      190/164
Proposed Piles/day.............................         10         10         10          7           10           3         10          3            6
Piles/day to calculate PTS.....................          5          5          5          4            5           2          5          2            3
Duration to drive pile (minutes)...............         30         na         12         na           na          na         12         na           na
Propagation....................................         15         15         15         15           15          15         15         15           15
Distance from source (meters)..................         10         10         10         10           10          10         10         10           10
Strikes per pile...............................         na       1000         na       1000         1000       25200         na      25200        50400
--------------------------------------------------------------------------------------------------------------------------------------------------------
* A.1) Vibratory Pile driving.
** E.1) Impact Pile Driving.


                                                   Table 8--Radial Distance to PTS Isopleths (meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Scenario                            Low-frequency   Mid-frequency  High-frequency      Phocid             Pile location
------------------------------------------------------------    cetaceans       cetaceans       cetaceans       pinnipeds   ----------------------------
                                                            ----------------------------------------------------------------
            Driving type                    Pile type         Distance from   Distance from   Distance from   Distance from
                                                              islands 1 & 2   islands 1 & 2   islands 1 & 2   islands 1 & 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact.............................  12-in. Timber.........              54             1.9              65               2  Mooring Dolphins.
                                     36-in. Steel..........           2,516              90           2,997           1,347  Omega Trestle, Temporary
                                                                                                                              Dock, Berm Wall West, and
                                                                                                                              Berm Wall East.
Impact with Bubble Curtain.........  36-in. Steel..........             997              36           1,188             534  Berm Wall West, Berm Wall
                                                                                                                              East, and Temporary Dock.
DTH--Impulsive.....................  42-in. Steel..........             737              26             878             395  Casing for Temporary Dock.
                                     36-in. Steel..........             737              26             878             395  Omega Trestle, Temporary
                                                                                                                              Dock, Berm Wall West, and
                                                                                                                              Berm Wall East.
DTH Simultaneous...................  42-in. Steel..........           1,534              55           1,827             821  Omega Trestle, Temporary
                                                                                                                              Dock, Berm Wall West, and
                                                                                                                              Berm Wall East.
DTH & Impact Hammer with bubble      36-and 42-in. Steel *.           1,734              62           2,066             929
 curtain: Simultaneous at the same
 island.
DTH at PI 1 and Impact with Bubble   36-and 42-in. Steel...  737 (Island 1)   26 (Island 1)  878 (Island 1)  395 (Island 1)
 Curtain Hammer at PI 2.                                     997 (Island 2)   36 (Island 2)   1,188 (Island  534 (Island 2)
                                                                                                         2)
Continuous (Vibratory).............  12-in. Timber.........               3             0.3               5               2  Mooring Dolphins.
                                     36-in. Steel..........              27               2              40              17  Mooring Piles and
                                                                                                                              Templates.
                                     42-in. Steel..........            * 27             * 2            * 40            * 17  Casing for Temporary Dock.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Activity will not occur on Portal Island 2.


[[Page 64864]]


                  Table 9--Radial Distance (meters) to Level B Harassment Monitoring Isopleths
----------------------------------------------------------------------------------------------------------------
                                                                       Distance from
             Driving method                        Pile type           island 1 & 2          Pile location
----------------------------------------------------------------------------------------------------------------
Impact..................................  12-in. Timber.............              22  Mooring Dolphins.
                                          36-in. Steel..............           1,555  Omega Trestle, Temporary
                                                                                       Dock, Berm Wall West, and
                                                                                       Berm Wall East.
Impact with Bubble Curtain..............  36-in. Steel..............             541  Berm Wall West, Berm Wall
                                                                                       East, and Temporary Dock.
DTH--Impulsive..........................  42-in. Steel..............           * 215  Casing for Temporary Dock.
                                          36-in. Steel..............             215  Omega Trestle, Temporary
                                                                                       Dock, Berm Wall West, and
                                                                                       Berm Wall East.
Continuous (Vibratory)..................  12-in. mooring............           1,354  Mooring Dolphins.
                                          36-in. Steel..............          21,544  Mooring Piles and
                                                                                       Templates.
                                          42-in. Steel..............        * 21,544  Casing for Temporary Dock.
----------------------------------------------------------------------------------------------------------------
* Activity will not occur on Portal Island 2.

Marine Mammal Occurrence and Take Calculation and Estimation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals and describe how it is 
brought together with the information above to produce a quantitative 
take estimate. When available, peer-reviewed scientific publications 
were used to estimate marine mammal abundance in the project area. In 
some cases population estimates, densities, and other quantitative 
information are lacking. Local observational data and estimated group 
size were utilized where applicable.
Humpback Whale
    Humpback whales are relatively rare in the Chesapeake Bay and 
density data for this species within the project vicinity were not 
available nor able to be calculated. Populations in the mid-Atlantic 
have been estimated for humpback whales off the coast of New Jersey 
with a density of 0.000130 per square kilometer (Whitt et al. 2015). 
Habitat-based density models produced by the Duke University Marine 
Geospatial Ecology Laboratory (Roberts et al. 2016) represent the best 
available information regarding marine mammal densities offshore near 
the mouth of the Chesapeake Bay. At the closest point to the PTST 
project area, humpback densities ranged from a high of 0.107/100 km\2\ 
in March to 0.00010/100 km\2\ in August. Furthermore, CTJV conducted 
marine mammal monitoring during SSV testing for 5 days in July 2019. 
During that time there were no sightings or takes of humpback whales.
    Because humpback whale occurrence is low as demonstrated above, 
CTJV and NMFS estimated that there will be a single humpback sighting 
every two months for the duration of in-water pile driving activities. 
Using an average group size of 2 animals, pile driving activities over 
a 10-month period would result in 10 takes of humpback whale by Level B 
harassment. No takes by Level A harassment are expected or proposed.
Bottlenose Dolphin
    Expected bottlenose dolphin take was estimated using a 2016 report 
on the occurrence, distribution, and density of marine mammals near 
Naval Station Norfolk and Virginia Beach, Virginia (Engelhaupt et al. 
2016). Three years of dolphin survey data were collected from either 
in-shore or open ocean transects. In-shore transects occurred off the 
coast of Virginia Beach in the Atlantic Ocean as well as inside the Bay 
to the southwest of the proposed project area. The previously issued 
IHA (83 FR 36522; July 30, 2018) used the same seasonal dolphin 
densities provided by Engelhaupt et al. (2016) to calculate take.
    CTJV used data from Engelhaupt et al. (2016) but employed a 
different methodology to estimate take for this IHA. Dolphin sightings 
are not uniformly distributed along the survey area. There were more 
sightings along the Atlantic coastal ocean and fewer along the 
shoreline within the Bay. It is likely that bottlenose dolphins do not 
use the habitat uniformly, but rather selectively based on 
heterogeneity in available habitat, dietary items and protection with 
some individuals preferring ocean and others estuary (Ballance, 1992; 
Gannon and Waples 2004). Although dolphins have the ability to move 
between these habitat types, Gannon and Waples (2004) suggest 
individuals prefer one habitat over the other based on gut contents of 
dietary items.
    Therefore, a subset of survey data from Engelhaupt et al. (2016) 
was used to determine seasonal dolphin densities in the Bay near the 
project area. A spatially refined approach was employed by plotting 
dolphin sightings within 12 km of the project location and then 
determining densities following methodology outlined in Engelhaupt et 
al. (2016) and Miller et al. (2019) using the package DISTANCE in R 
statistical software. The distance of 12 km was selected for estimating 
dolphin densities because uncertainty increases in extrapolating those 
data out further from the geographical location of the survey. 
Additionally, most of the sound generated by the proposed project will 
be directed into the Bay where dolphin densities are less compared to 
coastal ocean regions. Therefore, a 12 km radius should provide more 
accurate density estimates near the proposed project area by excluding 
higher density data from the coastal ocean areas.
    Transect distance and areas were determined by using Image J 
software (NIH Freeware) to trace individual transects within the 
calculated Level B harassment zones. The entire length of the transects 
was also calculated using Image J to determine the viability of this 
approach where the average transect zig-zag from Image J was 3.6 km 
compared to the methods in the report of a 3.7 km transect. Dolphin 
sightings were truncated at 0.32 km from the transect line based on the 
probability of accurate abundance estimations following the approach 
from Engelhaupt et al. (2016). Density estimates were stratified based 
on seasons (as defined by Engelhaupt et al. 2016) where there would be 
sufficient data to run the model, as monthly density estimates did not 
have enough data points. Seasonal densities are below in Table 10 and 
Level B harassment zone areas are shown in Table 11.

 Table 10--Bottlenose Dolphin Densities (Individual/km\2\) From Inshore
                            Areas of Virginia
------------------------------------------------------------------------
                                                       Density within 12
                        Season                           km of project
                                                              area
------------------------------------------------------------------------
Spring...............................................                0.6
Summer...............................................               0.62
Fall.................................................               1.17
Winter...............................................               0.26
------------------------------------------------------------------------


[[Page 64865]]


 Table 11--In-Water Area (km\2\) Used for Calculating Dolphin Takes per Construction Components per Hammer Type
----------------------------------------------------------------------------------------------------------------
                                                    Impact with      Vibratory     Impact + DTH      DTH + DTH
     Construction component        Impact hammer  bubble curtain      hammer          hammers         hammers
----------------------------------------------------------------------------------------------------------------
Mooring Cluster.................           0.003           0.003            4.16  ..............  ..............
Temporary Dock..................            5.55            0.63             830  ..............            0.25
Omega Trestle and West O-pile               8.55            8.55             830            1.72            0.49
 wall...........................
East O-Pile Walls...............  ..............  ..............  ..............            1.43  ..............
----------------------------------------------------------------------------------------------------------------

    Densities from Table 10 and harassment zone areas from Table 11 
were used to calculate the monthly takes based on the number of pile 
driving days. The number of dolphin takes per construction component 
per pile driving method was then summed for each month (Table 12). NMFS 
proposes to authorize 10,109 incidents of take for bottlenose dolphin 
by Level B harassment as shown in Table 12 and has split out the three 
dolphin stocks as shown in Table 13. There is insufficient information 
to apportion the takes precisely to the three stocks present in the 
area. Given that most of the NNCES stock are found in the Pamlico Sound 
estuarine system, NMFS will assume that no more than 200 of the 
proposed takes will be from this stock. A subset of these 200 takes 
would likely be comprised of Bay resident dolphins, although the number 
is unknown. Since members of the northern migratory coastal and 
southern migratory coastal stocks are thought to occur in or near the 
Bay in greater numbers, we will conservatively assume that no more than 
half of the remaining animals (9,909) will accrue to either of these 
stocks.
    During 5 days of SSV testing conducted by CTJV in July 2019, 
dolphins were recorded every day with a minimum daily sighting rate of 
8 (July 22, 2019 and maximum daily rate of 40 animals (July 23, 2019). 
There were 116 total sightings of which 50 were recorded as takes by 
Level B harassment. For comparative purposes, the average daily dolphin 
take rate estimated for the proposed IHA is 54 animals while the 
maximum sightings per day was 40 animals as noted above. Given this 
information, NMFS is confident that the proposed dolphin take estimate 
is reasonable, if somewhat conservative.

                                                            Table 12--Estimated Bottlenose Dolphin Take by Month and Driving Activity
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                     Month                       November    December    January    February    March      April       May        June       July      August    September   October
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dolphin Density (n/km2).......................        1.17        0.26       0.26       0.26        0.6        0.6        0.6       0.62       0.62       0.62        1.17       1.17
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         Mooring Cluster
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory--Timber Piles.......................           7           2          0          0          0          0          0          0          0          0           0          0
Impact--Timber Piles..........................           3           1          0          0          0          0          0          0          0          0           0          0
Dolphin Takes.................................          34           2          0          0          0          0          0          0          0          0           0          0         36
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         Temporary Dock
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Impact--Steel Pile............................           0           1          1          1          1          1          1          0          0          0           0          0
Impact with Bubble Curtain--Steel Pile........           0           2          2          2          2          2          2          0          0          0           0          0
Vibratory--Steel Pile.........................           0           4          4          4          4          4          4          0          0          0           0          0
Two DTH--Steel Pile...........................           0           3          3          3          3          3          3          0          0          0           0          0
Dolphin Takes.................................           0         865        649        649      1,499      1,499      1,499          0          0          0           0          0      6,660
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Omega Trestle/West O-pile Walls/Mooring Piles & Templates
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Impact--Steel Pile............................           2           2          2          2          4          3          2          0          0          0           0          0
Vibratory--Steel Pile.........................           1           1          0          0          0          0          1          1          1          1           0          0
Two DTH--Steel Pile...........................           2           2          2          2          6          4          4          0          0          0           0          0
DTH+ Impact--Steel Pile.......................           3           3          3          3          8          6          4          0          0          0           0          0
Dolphin Takes.................................         998         222          6          6         31         23        514        515        515        515           0          0      3,343
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                 Omega Trestle/East O-Pile Walls
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Impact--Steel Pile............................           0           2          2          2          2          4          2          2          2          2           0          0
DTH+ Impact--Steel Pile.......................           0           1          1          1          1          2          1          1          1          1           0          0
Two DTH--Steel Pile...........................           0           1          1          1          1          2          1          1          1          1           0          0
Dolphin Takes.................................           0           4          4          4          8         16          8          9          9          9           0          0         70
Total No. of Pile Driving Days per Month......          18          25         21         21         32         31         25          5          5          5           0          0
                                               -------------------------------------------------------------------------------------------------------------------------------------------------
    Total Level B harassment Takes............  ..........  ..........  .........  .........  .........  .........  .........  .........  .........  .........  ..........  .........     10,109
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Harbor Porpoise
    Given that harbor porpoises are uncommon in the project area, this 
exposure analysis assumes that there is a porpoise sighting once during 
every two months of operations which would equate to five sightings 
over ten months. Assuming an average group size of two (Hansen et al. 
2018; Elliser et al. 2018) over 10 months of in-water work results in a 
total of 10 estimated takes of porpoises. Harbor porpoises are members 
of the high-frequency hearing group which have Level A harassment 
isopleths as large as 2,997 m during impact installation of four piles 
per day. Given the relatively large Level A harassment zones during 
impact driving, NMFS assumed in the previous IHA (83 FR 36522; July 30, 
2018) that 40 percent of estimated porpoises takes would be by Level A 
harassment and authorized 4 takes of porpoises by Level A and 6 takes 
by Level B harassment. CTJV conducted marine mammal monitoring during 
SSV testing at the

[[Page 64866]]

project location for 5 days in July 2019. During that time there were 
no sightings or takes of porpoises. However, NMFS is conservatively 
proposing to authorize the same number of porpoise takes for Level A 
and Level B harassment for this IHA.
Harbor Seal
    The number of harbor seals expected to be present in the PTST 
project area was estimated using survey data for in-water and hauled 
out seals collected by the United States Navy at the portal islands 
from November 2014 through April 2018 (Rees et al., 2016; Jones et al. 
2018). The survey data revealed a daily maximum of 45 animals during 
this period which occurred in January, 2018. The maximum number of 
animals observed per day (45) was multiplied by the total number of 
proposed driving days between November and May (173) since (seals are 
not present in the area from June through October). Based on this 
calculation NMFS proposes to authorize 7,785 incidental takes of harbor 
seal. Note that the CTJV monitoring report did not record any seal 
observations over 5 days of SSV testing, but this would be expected as 
seals are not present during July.
    The largest Level A harassment isopleth for phocid species is 
approximately 1,347 meters which would occur during impact driving of 
36-inch steel piles. The smallest Level A harassment isopleths are 2 m 
and would occur during impact and vibratory driving of 12-inch timber 
piles. NMFS has prescribed a shutdown zone for harbor seals of 15 
meters as a mitigation measure since seals are common in the project 
area and are known to approach the shoreline. A larger shutdown zone 
would likely result in multiple shutdowns and impede the project 
schedule. From the previously issued IHA, NMFS assumed that 40 percent 
of the exposed seals will occur within the Level A harassment zone 
specified for a given scenario and the remaining affected seals would 
result in Level B harassment takes. Therefore, NMFS proposes to 
authorize 3,114 takes by Level A harassment and 4,671 takes by Level B 
harassment.
Gray Seal
    The number of gray seals expected to be present at the PTST project 
area was estimated using survey data collected by the U.S. Navy at the 
portal islands from 2014 through 2018 (Rees et al. 2016; Jones et al. 
2018). One seal was observed in February of 2015 and one seal was 
recorded in February of 2016 while no seals were observed at any time 
during 2017 or 2018. Since seals are anticipated to occur only during 
the month of February at a rate of 1 animal per day for the anticipated 
21 in-water work days during that month, NMFS proposes to authorized 21 
incidental takes of gray seal. The Level A isopleths for gray seals are 
identical to those for harbor seals. With a shutdown zone of 15 meters, 
previously, NMFS previously estimated 40 of the total take (not 40 
percent of the affected species or stock) would occur in the Level A 
harassment zone specified for a given scenario. Therefore, NMFS 
proposes to authorize 8 takes by Level A harassment and 13 takes by 
Level B harassment.
    Table 13 shows that estimated percentage of stock proposed for take 
by both Level A and Level B harassment.

                           Table 13--Estimated Take by Level A and Level B Harassment
----------------------------------------------------------------------------------------------------------------
                    Species                                   Stock                Level A takes   Level B takes
----------------------------------------------------------------------------------------------------------------
Humpback whale................................  Gulf of Maine...................  ..............              10
Harbor porpoise...............................  Gulf of Maine/Bay of Fundy......               4               6
Bottlenose dolphin............................  WNA Coastal, Northern Migratory.  ..............           4,955
                                                WNA Coastal, Southern Migratory.  ..............           4,954
                                                NNCES...........................  ..............             200
Harbor seal...................................  Western North Atlantic..........           3,114           4,671
Gray seal.....................................  Western North Atlantic..........               8              13
----------------------------------------------------------------------------------------------------------------

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 such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting such 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) the practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    In addition to the measures described later in this section, CTJV 
will employ the following standard mitigation measures:
     Conduct briefings between construction supervisors and 
crews and the marine mammal monitoring team prior to the start of all 
pile driving activity, and when new personnel join the work, to explain 
responsibilities, communication procedures, marine mammal monitoring 
protocol, and operational procedures;
     For in-water heavy machinery work other than pile driving 
(e.g., standard barges, etc.), if a marine mammal comes

[[Page 64867]]

within 10 m, operations shall cease and vessels shall reduce speed to 
the minimum level required to maintain steerage and safe working 
conditions. This type of work could include the following activities: 
(1) Movement of the barge to the pile location; or (2) positioning of 
the pile on the substrate via a crane (i.e., stabbing the pile);
     Work may only occur during daylight hours, when visual 
monitoring of marine mammals can be conducted;
     For those marine mammals for which Level B harassment take 
has not been requested, in-water pile driving will shut down 
immediately if such species are observed within or entering the 
monitoring zone (i.e., Level B harassment zone); and
     If take reaches the authorized limit for an authorized 
species, pile installation will be stopped as these species approach 
the Level B harassment zone to avoid additional take.
    The following measures would apply to CTJV's mitigation 
requirements:
    Establishment of Shutdown Zone--For all pile driving and drilling 
activities, CTJV would establish a shutdown zone. The purpose of a 
shutdown zone is generally to define an area within which shutdown of 
activity would occur upon sighting of a marine mammal (or in 
anticipation of an animal entering the defined area). These shutdown 
zones would be used to prevent incidental Level A harassment from 
impact pile driving for bottlenose dolphins and humpback whales. 
Shutdown zones for species proposed for authorization are as follows:
     100 meters for harbor porpoise and bottlenose dolphin.
     15 meters for harbor seal and gray seal.
     For humpback whale, shutdown distances are shown in Table 
14 under low-frequency cetaceans and are dependent on activity type.
    Establishment of Monitoring Zones for Level A and Level B 
Harassment--CTJV would establish monitoring zones based on calculated 
Level A harassment isopleths associated with specific pile driving 
activities and scenarios. These are areas beyond the established 
shutdown zone in which animals could be exposed to sound levels that 
could result in Level A harassment in the form of PTS. CTJV would also 
establish and monitor Level B harassment zones which are areas where 
SPLs are equal to or exceed the 160 dB rms threshold for impact driving 
and DTH drilling and 120 dB rms threshold during vibratory driving. 
Monitoring zones provide utility for observing by establishing 
monitoring protocols for areas adjacent to the shutdown zones. The 
monitoring zones enable observers to be aware of and communicate the 
presence of marine mammals in the project area outside the shutdown 
zone and thus prepare for a potential cease of activity should the 
animal enter the shutdown zone. The proposed Level A and Level B 
harassment monitoring zones are described in Table 14. Since some of 
the Level B harassment monitoring zones cannot be effectively observed 
in their entirety, Level B harassment exposures will be recorded and 
extrapolated based upon the number of observed take and the percentage 
of the Level B harassment zone that was not visible.

                              Table 14--Level A and Level B Harassment Monitoring Zones During Project Activities (meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                Scenario                                                     Level A harassment zones                         Level B
-----------------------------------------------------------------------------------------------------------------------------------------   monitoring
                                                                           Low-frequency   Mid-frequency       High-          Phocid           zones
                                                                             cetaceans       cetaceans       frequency       pinnipeds   ---------------
               Driving type                           Pile type          --------------------------------    cetaceans   ----------------
                                                                                                         ----------------                  Island 1 & 2
                                                                           Island 1 & 2   Island 1 & 2 *   Island 1 & 2    Island 1 & 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact....................................  12-in. Timber...............              55  ..............  ..............  ..............              25
                                            36-in. Steel................           2,520  ..............           3,000           1,350           1,585
Impact with Bubble Curtain................  36-in. Steel................           1,000  ..............           1,190             540             545
DTH--Impulsive............................  42-in. Steel................             740  ..............             880             395             220
DTH Simultaneous at same island...........  42-in. Steel................           1,535  ..............           1,830             825             220
DTH & Impact Hammer with bubble curtain:    36- and 42-in. Steel........           1,735  ..............           2,070             930             545
 Simultaneous at the same island.
DTH at PI 1. And Impact with Bubble         36- and 42-in. Steel........             740  ..............             880             395   220 from PI 1
 Curtain Hammer at PI 2.                                                                                                                   545 from PI 2
Continuous (Vibratory)....................  12-in. Timber...............  ..............  ..............  ..............  ..............           1,360
                                            36-in. Steel................              30  ..............  ..............              20          21,545
                                            42-in.** Steel..............              30  ..............  ..............              20          21,545
--------------------------------------------------------------------------------------------------------------------------------------------------------
* indicates that shutdown zone is larger than calculated harassment zone.
** Activity only proposed at Portal Island 1 as part of project pile driving plan.

    Soft Start--The use of soft-start procedures are believed to 
provide additional protection to marine mammals by providing warning 
and/or giving marine mammals a chance to leave the area prior to the 
hammer operating at full capacity. For impact pile driving, contractors 
would be required to provide an initial set of strikes from the hammer 
at reduced energy, with each strike followed by a 30-second waiting 
period. This procedure would be conducted a total of three times before 
impact pile driving begins. Soft start would be implemented at the 
start of each day's impact pile driving and at any time following 
cessation of impact pile driving for a period of 30 minutes or longer. 
Soft start is not required during vibratory or DTH pile driving 
activities.
    Use of bubble curtains--Use of air bubble curtain system would be 
implemented by CTJV during impact driving of 36-in steel piles except 
in water less than 10 ft in depth. The use of this sound attenuation 
device will reduce SPLs and the size of the zones of influence for 
Level A harassment and Level B harassment. Bubble curtains would meet 
the following requirements:
     The bubble curtain must distribute air bubbles around 100 
percent of the piling perimeter for the full depth of the water column.
     The lowest bubble ring shall be in contact with the 
mudline and/or rock bottom for the full circumference of the ring, and 
the weights attached to the bottom ring shall ensure 100 percent 
mudline and/or rock bottom contact. No parts of the ring or other 
objects shall

[[Page 64868]]

prevent full mudline and/or rock bottom contact.
     The bubble curtain shall be operated such that there is 
proper (equal) balancing of air flow to all bubblers.
     The applicant shall require that construction contractors 
train personnel in the proper balancing of air flow to the bubblers and 
corrections to the attenuation device to meet the performance 
standards. This shall occur prior to the initiation of pile driving 
activities.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving of 30 
minutes or longer occurs, protected species observers (PSOs) will 
observe the shutdown and monitoring zones for a period of 30 minutes. 
The shutdown zone will be cleared when a marine mammal has not been 
observed within the zone for that 30-minute period. If a marine mammal 
is observed within the shutdown zone, a soft-start cannot proceed until 
the animal has left the zone or has not been observed for 15 minutes. 
If the Level B harassment zone has been observed for 30 minutes and 
non-permitted species are not present within the zone, soft start 
procedures can commence and work can continue even if visibility 
becomes impaired within the Level B harassment monitoring zone. When a 
marine mammal permitted for take by Level B harassment is present in 
the Level B harassment zone, activities may begin and Level B 
harassment take will be recorded. If work ceases for more than 30 
minutes, the pre-activity monitoring of both the Level B harassment and 
shutdown zone will commence again.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

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 in the 
proposed action area. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     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).
     Mitigation and monitoring effectiveness.

Marine Mammal Visual Monitoring

    Monitoring shall be conducted by NMFS-approved observers. Trained 
observers shall be placed from the best vantage point(s) practicable to 
monitor for marine mammals and implement shutdown or delay procedures 
when applicable through communication with the equipment operator. 
Observer training must be provided prior to project start, and shall 
include instruction on species identification (sufficient to 
distinguish the species in the project area), description and 
categorization of observed behaviors and interpretation of behaviors 
that may be construed as being reactions to the specified activity, 
proper completion of data forms, and other basic components of 
biological monitoring, including tracking of observed animals or groups 
of animals such that repeat sound exposures may be attributed to 
individuals (to the extent possible).
    Monitoring would be conducted 30 minutes before, during, and 30 
minutes after pile driving activities. In addition, observers shall 
record all incidents of marine mammal occurrence, regardless of 
distance from activity, and shall document any behavioral reactions in 
concert with distance from piles being driven. Pile driving activities 
include the time to install a single pile or series of piles, as long 
as the time elapsed between uses of the pile driving equipment is no 
more than 30 minutes.
    CTJV would be required to station PSOs at locations offering the 
best available views of the monitoring zones. At least one PSO must be 
located in close proximity to each pile driving rig during active 
operation of single or multiple, concurrent driving devices. A minimum 
of one additional PSO is required at each active driving rig if the 
Level B harassment zone and shutdown zones cannot reasonably be 
observed by one PSO.
    PSOs would scan the waters using binoculars, and/or spotting 
scopes, and would use a handheld GPS or range-finder device to verify 
the distance to each sighting from the project site. All PSOs would be 
trained in marine mammal identification and behaviors and are required 
to have no other project-related tasks while conducting monitoring. In 
addition, monitoring will be conducted by qualified observers, who will 
be placed at the best vantage point(s) practicable to monitor for 
marine mammals and implement shutdown/delay procedures when applicable 
by calling for the shutdown to the hammer operator. CTJV would adhere 
to the following PSO qualifications:
    (i) Independent observers (i.e., not construction personnel) are 
required.
    (ii) At least one observer must have prior experience working as an 
observer.
    (iii) Other observers may substitute education (degree in 
biological science or related field) or training for experience.
    (iv) Where a team of three or more observers are required, one 
observer shall be designated as lead observer or monitoring 
coordinator. The lead observer must have prior experience working as an 
observer.
    (v) CTJV shall submit observer CVs for approval by NMFS.
    Additional standard observer qualifications include:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals,

[[Page 64869]]

including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates and times when in-water construction 
activities were suspended to avoid potential incidental injury from 
construction sound of marine mammals observed within a defined shutdown 
zone; and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Observers will be required to use approved data forms. Among other 
pieces of information, CTJV will record detailed information about any 
implementation of shutdowns, including the distance of animals to the 
pile and description of specific actions that ensued and resulting 
behavior of the animal, if any. In addition, CTJV will attempt to 
distinguish between the number of individual animals taken and the 
number of incidences of take. We require that, at a minimum, the 
following information be collected on the sighting forms:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Weather parameters (e.g., percent cover, visibility);
     Water conditions (e.g., sea state, tide state);
     Species, numbers, and, if possible, sex and age class of 
marine mammals;
     Description of any observable marine mammal behavior 
patterns, including bearing and direction of travel and distance from 
pile driving activity, and if possible, the correlation to SPLs;
     Distance from pile driving activities to marine mammals 
and distance from the marine mammals to the observation point;
     Description of implementation of mitigation measures 
(e.g., shutdown or delay);
     Locations of all marine mammal observations; and
     Other human activity in the area.

Reporting

    A draft report would be submitted to NMFS within 90 days of the 
completion of marine mammal monitoring, or 60 days prior to the 
requested date of issuance of any future IHA for projects at the same 
location, whichever comes first. The report will include marine mammal 
observations pre-activity, during-activity, and post-activity during 
pile driving days (and associated PSO data sheets), and will also 
provide descriptions of any behavioral responses to construction 
activities by marine mammals and a complete description of all 
mitigation shutdowns and the results of those actions and an 
extrapolated total take estimate based on the number of marine mammals 
observed during the course of construction. A final report must be 
submitted within 30 days following resolution of comments on the draft 
report.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, CTJV shall report the 
incident to the Office of Protected Resources (OPR), NMFS and to the 
Greater Atlantic Region New England/Mid-Atlantic Regional Stranding 
Coordinator as soon as feasible. The report must include the following 
information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    Pile driving activities associated with the proposed PTST project, 
as outlined previously, have the potential to disturb or displace 
marine mammals. The specified activities may result in take, in the 
form of Level B harassment (behavioral disturbance) or Level A 
harassment (auditory injury), incidental to underwater sounds generated 
from pile driving. Potential takes could occur if individuals are 
present in the ensonified zone when pile driving occurs. Level A 
harassment is only anticipated for harbor porpoises, harbor seals, and 
gray seals.
    No serious injury or mortality is anticipated given the nature of 
the activities and measures designed to minimize the possibility of 
injury to marine mammals. The potential for these outcomes is minimized 
through the construction method and the implementation of the planned 
mitigation measures. Specifically, vibratory driving, impact driving, 
and drilling with DTH hammers will be the primary methods of 
installation and pile removal will occur with a vibratory hammer. 
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 bubble curtains, soft start and 
shutdown zones significantly reduces 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 that is 
annoying prior to it becoming potentially injurious.
    CTJV will use qualified PSOs stationed strategically to increase 
detectability of marine mammals, enabling a high rate of success in 
implementation of shutdowns to avoid injury for most species. PSOs will 
be stationed on a specific Portal Island

[[Page 64870]]

whenever pile driving operations are underway at that location. More 
than one PSO may be stationed on an island in order to provide a 
relatively clear view of the shutdown zone and monitoring zones. These 
factors will limit exposure of animals to noise levels that could 
result in injury.
    CTJV's proposed pile driving activities are highly localized. Only 
a relatively small portion of the Chesapeake Bay may be affected. 
Localized noise exposures produced by project activities may cause 
short-term behavioral modifications in affected cetaceans and pinnipeds 
Moreover, the proposed mitigation and monitoring measures are expected 
to further reduce the likelihood of injury as well as reduce behavioral 
disturbances.
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from other 
similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring) (e.g., Thorson and Reyff 
2006). Individual animals, even if taken multiple times, will most 
likely 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 along both 
Atlantic and Pacific coasts, which have taken place with no known long-
term adverse consequences from behavioral harassment. Furthermore, many 
projects similar to this one are also believed to result in multiple 
takes of individual animals without any documented long-term adverse 
effects. Level B harassment will be minimized 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.
    In addition to the expected effects resulting from authorized Level 
B harassment, we anticipate that small numbers of harbor porpoises, 
harbor seals and gray seals may sustain some limited Level A harassment 
in the form of auditory injury. However, animals that experience PTS 
would likely only receive slight PTS, i.e. minor degradation of hearing 
capabilities within regions of hearing that align most completely with 
the energy produced by pile driving (i.e., the low-frequency region 
below 2 kHz), not severe hearing impairment or impairment in the 
regions of greatest hearing sensitivity. If hearing impairment occurs, 
it is most likely that the affected animal's threshold would increase 
by a few dBs, which is not likely to meaningfully affect its ability to 
forage and communicate with conspecifics. As described above, we expect 
that marine mammals would be likely to move away from a sound source 
that represents an aversive stimulus, especially at levels that would 
be expected to result in PTS, given sufficient notice through use of 
soft start.
    The project is not expected to have significant adverse effects on 
marine mammal habitat. No important feeding and/or reproductive areas 
for marine mammals are known to be near the project area. Project 
activities would not permanently modify existing marine mammal habitat. 
The activities may cause some fish to leave the area of disturbance, 
thus temporarily impacting marine mammal foraging opportunities in a 
limited portion of the foraging range. However, because of the 
relatively small area of the habitat that may be affected, the impacts 
to marine mammal habitat are not expected to cause significant or long-
term negative consequences.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality is anticipated or authorized;
     Limited Level A harassment exposures (harbor porpoises, 
harbor seals, and gray seals) are anticipated to result only in slight 
PTS, within the lower frequencies associated with pile driving;
     The anticipated incidents of Level B harassment consist 
of, at worst, temporary modifications in behavior that would not result 
in fitness impacts to individuals;
     The specified activity and associated ensonifed areas are 
very small relative to the overall habitat ranges of all species and 
does not include habitat areas of special significance (BIAs or ESA-
designated critical habitat); and
     The presumed efficacy of the proposed mitigation measures 
in reducing the effects of the specified activity.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. Additionally, other qualitative 
factors may be considered in the analysis, such as the temporal or 
spatial scale of the activities.
    The proposed take of marine mammal stocks comprises less than 10.2 
percent of the Western North Atlantic harbor seal stock abundance, and 
less than one percent of the other stocks, with the exception of 
bottlenose dolphin stocks. There are three bottlenose dolphin stocks 
that could occur in the project area. Therefore, the estimated 10,109 
dolphin takes by Level B harassment would likely be split among the 
western North Atlantic northern migratory coastal stock, western North 
Atlantic southern migratory coastal stock, and NNCES stock. Based on 
the stocks' respective occurrence in the area, NMFS estimated that 
there would be 200 takes from the NNCES stock, with the remaining takes 
split evenly between the northern and southern migratory coastal 
stocks. Based on consideration of various factors described below, we 
have determined the numbers of individuals taken would comprise less 
than one-third of the best available population abundance estimate of 
either coastal migratory stock. Detailed descriptions of the stocks' 
ranges have been provided in Description of Marine Mammals in the Area 
of Specified Activities.
    Both the northern migratory coastal and southern migratory coastal 
stocks have expansive ranges and they are the only dolphin stocks 
thought to make broad-scale, seasonal migrations in coastal waters of 
the western North Atlantic. Given the large ranges associated with 
these two stocks it is unlikely that large segments of either stock 
would approach the project area and enter into the Bay. The majority of 
both stocks are likely to be found widely dispersed across their 
respective habitat

[[Page 64871]]

ranges and unlikely to be concentrated in or near the Chesapeake Bay.
    Furthermore, the Chesapeake Bay and nearby offshore waters 
represent the boundaries of the ranges of each of the two coastal 
stocks during migration. The northern migratory coastal stock is found 
during warm water months from coastal Virginia, including the 
Chesapeake Bay and Long Island, New York. The stock migrates south in 
late summer and fall. During cold water months dolphins may be found in 
coastal waters from Cape Lookout, North Carolina, to the North 
Carolina/Virginia. During January-March, the southern migratory coastal 
stock appears to move as far south as northern Florida. From April to 
June, the stock moves back north to North Carolina. During the warm 
water months of July-August, the stock is presumed to occupy coastal 
waters north of Cape Lookout, North Carolina, to Assateague, Virginia, 
including the Chesapeake Bay. There is likely some overlap between the 
northern and southern migratory stocks during spring and fall 
migrations, but the extent of overlap is unknown.
    The Bay and waters offshore of the mouth are located on the 
periphery of the migratory ranges of both coastal stocks (although 
during different seasons). Additionally, each of the migratory coastal 
stocks are likely to be located in the vicinity of the Bay for 
relatively short timeframes. Given the limited number of animals from 
each migratory coastal stock likely to be found at the seasonal 
migratory boundaries of their respective ranges, in combination with 
the short time periods (~two months) animals might remain at these 
boundaries, it is reasonable to assume that takes are likely to occur 
only within some small portion of either of the migratory coastal 
stocks.
    Both migratory coastal stocks likely overlap with the NNCES stock 
at various times during their seasonal migrations. The NNCES stock is 
defined as animals that primarily occupy waters of the Pamlico Sound 
estuarine system (which also includes Core, Roanoke, and Albemarle 
sounds, and the Neuse River) during warm water months (July-August). 
Members of this stock also use coastal waters (<=1 km from shore) of 
North Carolina from Beaufort north to Virginia Beach, Virginia, 
including the lower Chesapeake Bay. Comparison of dolphin photo-
identification data confirmed that limited numbers of individual 
dolphins observed in Roanoke Sound have also been sighted in the 
Chesapeake Bay (Young 2018). Like the migratory coastal dolphin stocks, 
the NNCES stock covers a large range. The spatial extent of most small 
and resident bottlenose dolphin populations is on the order of 500 
km\2\, while the NNCES stock occupies over 8,000 km\2\ (LeBrecque et 
al. 2015). Given this large range, it is again unlikely that a 
preponderance of animals from the NNCES stock would depart the North 
Carolina estuarine system and travel to the northern extent of the 
stock's range. However, recent evidence suggests that there is like a 
small resident community of NNCES dolphins that inhabits the Chesapeake 
Bay year-round (Patterson, Pers. Comm).
    Many of the dolphin observations in the Bay are likely repeated 
sightings of the same individuals. The Potomac-Chesapeake Dolphin 
Project has observed over 1,200 unique animals since observations began 
in 2015. Re-sightings of the same individual can be highly variable. 
Some dolphins are observed once per year, while others are highly 
regular with greater than 10 sightings per year (Mann, pers. comm.). 
Multiple sightings of the same individual would considerably reduce the 
number of individual animals that are taken by harassment. Furthermore, 
the existence of a resident dolphin population in the Bay would 
increase the percentage of dolphin takes that are actually re-sightings 
of the same individuals.
    In summary and as described above, the following factors primarily 
support our preliminary determination regarding the incidental take of 
small numbers of a species or stock:
     The take of marine mammal stocks proposed for 
authorization comprises less than 9 percent of any stock abundance 
(with the exception of bottlenose dolphin stocks);
     Potential bottlenose dolphin takes in the project area are 
likely to be allocated among three distinct stocks;
     Bottlenose dolphin stocks in the project area have 
extensive ranges and it would be unlikely to find a high percentage of 
any one stock concentrated in a relatively small area such as the 
project area or the Bay;
     The Bay represents the migratory boundary for each of the 
specified dolphin stocks and it would be unlikely to find a high 
percentage of any stock concentrated at such boundaries; and
     Many of the takes would be repeats of the same animal and 
it is likely that a number of individual animals could be taken 10 or 
more times.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Endangered Species Act (ESA)

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat.
    No incidental take of ESA-listed species is 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 CTJV for conducting pile driving activities as part 
of the PTST project for a period of one year from the date of issuance, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. A draft of the proposed IHA can be found 
at https://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 PTST 
project. We also request at this time comment on the potential renewal 
of this proposed IHA as described in the paragraph below. Please 
include with your comments any supporting data or literature citations 
to help inform decisions on the request for this IHA or a subsequent 
Renewal.
    On a case-by-case basis, NMFS may issue a one-year IHA renewal with 
an additional 15 days for public comments when (1) another year of 
identical or nearly identical activities as described in the Specified 
Activities section of this notice is planned or (2) the activities as 
described in the Specified Activities section of this notice would

[[Page 64872]]

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 expiration of the current IHA.
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal 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 
because only a subset of the initially analyzed activities remain to be 
completed under the Renewal).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for Renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: November 19, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2019-25471 Filed 11-22-19; 8:45 am]
 BILLING CODE 3510-22-P