Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel Project in Virginia Beach, Virginia, 64847-64872 [2019-25471]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[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
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                                                                                                     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
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* 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\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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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)
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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).
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                                                         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 remai