[Federal Register Volume 88, Number 247 (Wednesday, December 27, 2023)]
[Notices]
[Pages 89385-89406]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-28514]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD544]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel 
Project, 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 
the 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-time, 1-year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider

[[Page 89386]]

public comments prior to making any final decision on the issuance of 
the requested MMPA authorization and agency responses will be 
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than January 
26, 2024.

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

FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected 
Resources, NMFS, (301) 427-8401.

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 proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or 
mortality) of the Companion Manual for NAO 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 July 28, 2023, NMFS received a request from CTJV for an IHA to 
take marine mammals incidental to in-water construction activities 
associated with the PTST project near Virginia Beach, VA. Following 
NMFS' review of the initial application, CTJV submitted several revised 
versions of the application based on NMFS' comments. The final version 
was submitted on November 7, 2023, and was deemed adequate and complete 
on November 13, 2023. CTJV's request is for take of 5 species by Level 
B harassment and, for a subset of three of these species, by Level A 
harassment. Neither CTJV nor NMFS expect serious injury or mortality to 
result from this activity and, therefore, an IHA is appropriate.
    NMFS most recently issued an IHA to CTJV for similar work on 
November 8, 2022, (87 FR 68462; November 15, 2022). CTJV complied with 
all the requirements (e.g., mitigation, monitoring, and reporting) of 
the previous IHA, and information regarding their monitoring results 
may be found in the Estimated Take section.
    This proposed IHA would cover 1 year of a larger project for which 
CTJV obtained IHAs for similar work (83 FR 36522, July 30, 2018; 85 FR 
16061, March 20, 2020; 86 FR 14606, March 17, 2021; 86 FR 67024, 
November 24, 2021; and 87 FR 68462, November 15, 2022). The larger 
multi-year 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 as part of the 23-mile Chesapeake 
Bay Bridge-Tunnel (CBBT) facility.

Description of Proposed Activity

Overview

    The purpose of the project is to build an additional two lane 
vehicle tunnel under the navigation channel as part of the CBBT. The 
PTST project will address existing constraints to regional mobility 
based on current traffic volume, improve safety, improve the ability to 
conduct necessary maintenance with minimal impact to traffic flow, and 
ensure reliable hurricane evacuation routes. In-water construction work 
would include the removal of a total of 158 36-inch steel piles on the 
temporary dock and trestle on Portal Islands Nos. 1 and 2 as well as 
the removal of steel mooring piles on both Portal Islands (97 total on 
Portal Island No.1); the removal of 36'' steel piles on the trestle (34 
total on Portal Island No. 2); and the removal of 36'' steel mooring 
piles on both Island 1 (9 piles) and Island No. 2 (18 piles). All steel 
piles are hollow pipe piles. The proposed impact and vibratory pile 
removal activities can introduce sound into the water environment which 
can result in take of marine mammals by behavioral harassment and, for 
some species, by auditory injury. Proposed construction activities are 
expected to be completed from January-April as well as in December 
2024. Note that the term ``pile driving'' is only used to refer to pile 
removal activities. No pile

[[Page 89387]]

installation activities are planned by CTJV.

Dates and Duration

    The proposed in-water removal of a total of 158 piles would occur 
over 80 days. Removal will begin on Portal Island No. 1 in January 
through April 2024 for 54 days then will resume on Portal Island No. 2 
in December 2024 for 26 days. No pile removal work will take place in 
the interim. The project schedule is shown in table 1.

Specific Geographic Region

    The PTST project is located between Portal Islands No.1 and No. 2 
of the CBBT as shown in Figure 1. A 6,525 lineal foot (ft) (1,989 
meters(m)) 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 and is maintained at a depth of 50 ft (15.2 m) MLLW.
[GRAPHIC] [TIFF OMITTED] TN27DE23.003

Figure 1--Map of Proposed Project Area Near Virginia Beach, Virginia

Detailed Description of the Specified Activity

    The PTST project consists of the construction of a two lane tunnel 
parallel and to the west of the existing tunnel, connecting Portal 
Islands No. 1 and No. 2. A tunnel boring machine (TBM) will 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 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.

[[Page 89388]]

    Descriptions of additional 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 during this IHA include the removal of 
36-inch steel piles on the temporary dock and trestle (97 total on 
Portal Island No.1) and the removal of 36-inch steel piles on the 
trestle (34 total on Portal Island No.2) as well as the removal of 36-
inch steel mooring piles on both Portal Islands (9 piles on Portal 
Island No. 1 and 18 total on Portal Island No. 2). A total of 158 piles 
will be removed over 80 in-water work days. Pile driving activities 
will be conducted by initially using an impact hammer, if necessary, to 
break the friction on the previously installed piles. If an impact 
hammer is not required to initially break friction, then a vibratory 
hammer will be used for extraction. If the pile cannot be removed with 
this method, the pile will then be cut off a minimum of three feet 
below the stabilized, post construction sediment-water interface. There 
will be no concurrent pile driving activity.

                                                     Table 1--Anticipated Pile Installation Schedule
                                                              [January 2024-December 2024]
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                                                                                                             Number of  Number of piles/
                                                                 Installation/    Bubble curtain   Number    days per       days per       Anticipated
        Pile location          Pile function      Pile type      removal method      (yes/no)     of piles   activity    activity (per     installation
                                                                                                              (total)     hammer type)         date
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Portal Island No. 1.........  Mooring          36-inch          Impact (if       Yes............         9           5  (2 Piles/Day)..  1 January
                               dolphins.        Diameter Steel   needed).        Yes............                     5  (2 Piles/Day)..   through 28
                                                Pipe Pile.      Vibratory                                                                 February 2024.
                                                                 (Removal).
Portal Island No. 1.........  Temporary Dock/  36-inch          Impact (if       Yes............        97          49  (2 Piles/Day)..  1 January
                               Trestle.         Diameter Steel   needed).        Yes............                    49  (2 Piles/Day)..   through 30
                                                Interlocked     Vibratory                                                                 April 2024.
                                                Pipe Piles.      (Removal).
Portal Island No. 2.........  Mooring          36-inch          Impact (if       Yes............        18           9  (2 Piles/Day)..  December 1-31,
                               dolphins.        Diameter Steel   needed).        Yes............                     9  (2 Piles/Day)..   2024.
                                                Pipe Pile.      Vibratory
                                                                 (Removal).
Portal Island No. 2.........  Omega Trestle..  36-inch          Impact (if       Yes............        34          17  (2 Piles/Day)..  December 1-31,
                                                Diameter Steel   needed).        Yes............                    17  (2 Piles/Day)..   2024.
                                                Interlocked     Vibratory
                                                Pipe Piles.      (Removal).
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    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting)

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' 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' website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this activity and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS' 
SARs). While no serious injury or mortality is anticipated or proposed 
to be authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Atlantic and Gulf of Mexico SARs (Hayes et al. 2023). All 
values presented in table 2 are the most recent available at the time 
of publication and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                                                  Table 2--Species Likely Impacted by the Specified Activities
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                                                                                              ESA/MMPA status;         Stock abundance (CV, Nmin, most recent                       Annual M/SI
             Common name                    Scientific name               Stock             Strategic (Y/N) \1\                abundance survey) \2\                    PBR             \3\
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                                                              Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals):
    Humpback whale...................  Megaptera novaeangliae..  Gulf of Maine..........  -,-; N.................                         1,393 (0; 1,375, 2016)              22           12.15
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                                                                Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:

[[Page 89389]]

 
    Bottlenose dolphin...............  Tursiops truncatus......  WNA Coastal, Northern    -,-; Y.................                      6,639 (0.41; 4,759; 2016)              48       12.2-21.5
                                                                  Migratory.
                                                                 WNA Coastal, Southern    -,-; Y.................                      3,751 (0.06; 2,353; 2016)              24          0-18.3
                                                                  Migratory.
                                                                 Northern North Carolina  -,-; Y.................                          823 (0.06; 782; 2017)             7.8          7.2-30
                                                                  Estuarine System.
Family Phocoenidae (porpoises):
    Harbor porpoise..................  Phocoena phocoena.......  Gulf of Maine/Bay of     -, -; N................                    95,543 (0.31; 74,034; 2016)             851             164
                                                                  Fundy.
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                                                                             Order Carnivora--Superfamily Pinnipedia
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Family Phocidae (earless seals):
    Harbor seal......................  Phoca vitulina..........  WNA....................  -, -; N................                    61,336 (0.08, 57,637, 2018)           1,729             339
    Gray seal \4\....................  Halichoerus grypus......  WNA....................  -, -; N................                    27,300 (0.22, 22,785, 2016)           1,458           4,453
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted
  under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be declining and likely to be listed under
  the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports. CV is coefficient of
  variation; Nmin is the minimum estimate of stock abundance.
\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
  Mortality/Serious Injury (M/SI) often cannot be determined precisely and is in some cases presented as a minimum value or range.
\4\ The NMFS stock abundance estimate applies to U.S. population only, however the actual stock abundance is approximately 505,000. The PBR value is estimated for the U.S. population, while
  the M/SI estimate is provided for the entire gray seal stock (including animals in Canada).

    As indicated above, all five species (with seven managed stocks) in 
table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. While North Atlantic 
right whale and fin whale could potentially occur in the area, 
occurrence of these species is very rare, the species are readily 
observed, and the applicant would shut down pile driving activity if 
they enter the project area. Thus take is not expected to occur, and 
they are not discussed further.

Humpback Whale

    The humpback whale is found worldwide in all oceans. In winter, 
humpback whales from waters off New England, Canada, Greenland, 
Iceland, and Norway migrate to mate and calve primarily in the West 
Indies, 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 Distinct Population 
Segments (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 has been a decline in whale sightings in the peak months 
since 2016/17; the distribution of whale sightings occur most 
frequently in the month of January through March (Aschettino et al., 
2021).
    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 an Unusual Mortality Event (UME) 
with 209 strandings recorded, 7 of which occurred in or near the mouth 
of the Chesapeake Bay. More detailed information is available at: 
https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2023-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. Biologists theorize that 
non-reproductive animals may be establishing a winter feeding range in 
the mid-Atlantic since they are not participating in reproductive

[[Page 89390]]

behavior in the Caribbean (Swingle et al., 1993).

Bottlenose Dolphin

    The bottlenose dolphin occurs in temperate and tropical oceans 
throughout the world (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 m deep (Hayes et al., 2021). 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., 
2017). 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. 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 NNCES stock (Garrison et al., 
2017).
    The southern migratory coastal stock migrates seasonally along the 
coast between North Carolina and northern Florida (Garrison et al., 
2017). 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, 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.
    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 (Eric Patterson, 
pers. communication).

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 m deep (Hayes et al., 2022). Harbor porpoises in 
the United States are made up of the Gulf of Maine/Bay of Fundy stock. 
Gulf of Maine/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 
(Hayes et al., 2022).
    Harbor porpoise occur seasonally in the winter and spring in small 
numbers near the project area. 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). In most areas, 
harbor porpoise occur in small groups of just a few individuals.

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 (Hayes et al., 2022). 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 haulout 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. They are primarily 
concentrated north of the project area at Portal Island No. 3. Over 8 
field seasons (2014-2015 through 2021-2022), 79.1 percent of seals were 
recorded at Portal Island No. 3; 17.4 percent were recorded at Portal 
Island No. 4; and 3.5 percent were recorded at Portal Island No. 1 and 
No. 2 combined (Jones and Rees 2023).
    Harbor seals are central-place foragers (Orians and Pearson, 1979) 
and tend to exhibit strong site fidelity within season and across 
years, generally forage close to haulout sites, and repeatedly visit 
specific foraging areas (Suryan and Harvey, 1998; Thompson et al., 
1998). Harbor seals tend to forage at night and haul out during the day 
with a peak in the afternoon between 1 p.m. and 4 p.m. (London et al., 
2001).

Gray Seal

    The gray seal occurs on both coasts of the Northern Atlantic Ocean 
and are divided into three major populations 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. In the United 
States, gray seals congregate in the summer to give birth at four 
established colonies in Massachusetts and Maine (Hayes et al., 2022). 
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).

[[Page 89391]]

Marine Mammal Hearing

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

                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
               Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen         7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,      150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true          275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus cruciger &
 L. australis).
Phocid pinnipeds (PW) (underwater) (true     50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea     60 Hz to 39 kHz.
 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 et al. 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

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

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 (American National Standards Institute 1995). 
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 to 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.
    Two types of hammers would be used on this project. Impact hammers 
operate by repeatedly dropping and/or pushing a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper, 2005). 
Vibratory hammers install piles by vibrating them and allowing the 
weight of the hammer to push them into the sediment. Vibratory hammers 
produce significantly less sound than impact hammers. Peak Sound 
Pressure Levels (SPLs) may be 180 dB or greater, but are generally 10 
to 20 dB lower than SPLs generated during impact pile driving of the 
same-sized pile (Oestman et al., 2009). Rise time is slower, reducing 
the probability and severity of injury, and sound energy is distributed 
over a greater amount of time (Nedwell and Edwards, 2002; Carlson et 
al., 2005).

[[Page 89392]]

    The likely or possible impacts of CTJV's proposed activities on 
marine mammals could be generated from both non-acoustic and acoustic 
stressors. Potential non-acoustic stressors include the physical 
presence of the equipment, vessels, 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 driving activities.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving activities is the primary means by which 
marine mammals may be harassed from CTJV's specified activities. In 
general, animals exposed to natural or anthropogenic sound may 
experience behavioral, physiological, and/or physical effects, ranging 
in magnitude from none to severe (Southall et al., 2007). Generally, 
exposure to pile driving activities has the potential to result in 
behavioral reactions (e.g., avoidance, temporary cessation of foraging 
and vocalizing, changes in dive behavior) and, in limited cases, 
auditory threshold shifts. Exposure to anthropogenic noise can also 
lead to non-observable physiological responses such as an increase in 
stress hormones. Additional noise in a marine mammal's habitat can mask 
acoustic cues used by marine mammals to carry out daily functions such 
as communication and predator and prey detection. The effects of pile 
driving activities 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. mother 
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., 2003; Southall et al., 2007). 
Here we discuss physical auditory effects (threshold shifts) followed 
by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    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 (Ward et al., 1958; Ward et al., 
1959; Ward, 1960; Kryter et al., 1966; Miller, 1974; Henderson et al., 
2008). PTS levels for marine mammals are estimates, because there are 
limited empirical data measuring PTS in marine mammals (e.g., Kastak et 
al., 2008), 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 
(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). 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 
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).
    Activities for this project include impact and vibratory pile 
driving. There would likely be pauses in activities producing the sound 
during each day. Given these pauses and the fact that many marine 
mammals are likely moving through the project areas and not remaining 
for extended periods of time, the potential for threshold shift 
declines.
    Behavioral harassment--Exposure to noise from pile driving 
activities has the potential to behaviorally disturb marine mammals. 
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

[[Page 89393]]

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; 
National Research Council (NRC), 2005).
    The following subsections provide examples of behavioral responses 
that provide an idea of the variability in behavioral responses that 
would be expected given the differential sensitivities of marine mammal 
species to sound and the wide range of potential acoustic sources to 
which a marine mammal may be exposed. Behavioral responses that could 
occur for a given sound exposure should be determined from the 
literature that is available for each species, or extrapolated from 
closely related species when no information exists, along with 
contextual factors. 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. 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 respiration, interference with or alteration of vocalization, 
avoidance, and flight.
    Pinnipeds may increase their haul out time, possibly to avoid in-
water disturbance (Thorson and Reyff, 2006). 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.
    Alteration of Feeding Behavior--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). In addition, behavioral state of the 
animal plays a role in the type and severity of a behavioral response, 
such as disruption to foraging (e.g., Silve et al., 2016; Wensveen et 
al., 2017). An evaluation of whether foraging disruptions would be 
likely to incur fitness consequences considers temporal and spatial 
scale of the activity in the context of the available foraging habitat 
and, in more severe cases may necessitate consideration of 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. Goldbogen 
et al. (2013) indicate that disruption of feeding and displacement 
could impact individual fitness and health. However, for this to be 
true, we would have to assume that an individual could not compensate 
for this lost feeding opportunity by either immediately feeding at 
another location, by feeding shortly after cessation of acoustic 
exposure, or by feeding at a later time. There is no indication this is 
the case here, particularly since prey would likely still be available 
in the environment in most cases following the cessation of acoustic 
exposure.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness. Neuroendocrine stress responses often involve the 
hypothalamus-pituitary-adrenal system. Virtually all neuroendocrine 
functions that are affected by stress--including immune competence, 
reproduction, metabolism, and behavior--are regulated by pituitary 
hormones. Stress-induced changes in the secretion of pituitary hormones 
have been implicated in failed reproduction, altered metabolism, 
reduced immune competence, and behavioral disturbance (e.g., Moberg, 
1987; Blecha, 2000). Increases in the circulation of glucocorticoids 
are also equated with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003), however 
distress is an unlikely result of these projects based on observations 
of marine mammals during previous, similar projects.
    Auditory 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,

[[Page 89394]]

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. The 
mouth of the Chesapeake Bay contains active military and commercial 
shipping, as well as numerous recreational and other commercial vessel 
and background sound levels in the area are already elevated.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal that have the potential to cause behavioral harassment, 
depending on their distance from 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. 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 
likely previously have been `taken' because of exposure to underwater 
sound above the behavioral harassment thresholds, which are generally 
larger than those associated with airborne sound. Thus, the behavioral 
harassment of these animals is already accounted for in these estimates 
of potential take. Therefore, we do not believe that authorization of 
additional incidental take resulting from airborne sound for pinnipeds 
is warranted, and airborne sound is not discussed further.

Marine Mammal Habitat Effects

    CTJV's proposed construction activities could have localized, 
temporary impacts on marine mammal habitat, including prey, by 
increasing in-water sound pressure levels and slightly decreasing water 
quality. Increased noise levels may affect acoustic habitat (see 
Auditory Masking discussion above) and adversely affect marine mammal 
prey in the vicinity of the project areas (see discussion below). 
Elevated levels of underwater noise would ensonify the project areas 
where both fishes and mammals occur and could affect foraging success. 
Additionally, marine mammals may avoid the area during construction; 
however, displacement due to noise is expected to be temporary and is 
not expected to result in long-term effects to the individuals or 
populations.
    In-water Construction Effects on Potential Prey--Construction 
activities would produce continuous (i.e., vibratory pile driving) and 
intermittent (i.e., impact pile driving) sounds. Sound may affect 
marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton). Marine mammal prey varies by species, season, and 
location. Here, we describe studies regarding the effects of noise on 
known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). Depending on their hearing anatomy and peripheral sensory 
structures, which vary among species, fishes hear sounds using pressure 
and particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds that are especially strong and/or intermittent 
low-frequency sounds, and behavioral responses such as flight or 
avoidance are the most likely effects. Short duration, sharp sounds can 
cause overt or subtle changes in fish behavior and local distribution. 
The reaction of fish to noise depends on the physiological state of the 
fish, past exposures, motivation (e.g., feeding, spawning, migration), 
and other environmental factors. Hastings and Popper (2005) identified 
several studies that suggest fish may relocate to avoid certain areas 
of sound energy. Additional studies have documented effects of pile 
driving on fish; several are based on studies in support of large, 
multiyear bridge construction projects (e.g., Scholik and Yan, 2001; 
Scholik and Yan, 2002; Popper and Hastings, 2009). Several studies have 
demonstrated that impulse sounds might affect the distribution and 
behavior of some fishes, potentially impacting foraging opportunities 
or increasing energetic costs (e.g., Fewtrell and McCauley, 2012; 
Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999; 
Paxton et al., 2017). However, some studies have shown no or slight 
reaction to impulse sounds (e.g., Pena et al., 2013; Wardle et al., 
2001; Jorgenson and Gyselman, 2009).
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4 to 6 dB was recoverable within 24 
hours for one species. Impacts would be most severe when the individual 
fish is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    The most likely impact to fishes 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,

[[Page 89395]]

distribution, and behavior is anticipated.
    Construction activities have the potential to have adverse impacts 
on forage fish in the project area in the form of increased turbidity. 
Forage fish form a significant prey base for many marine mammal species 
that occur in the project area. Turbidity within the water column has 
the potential to reduce the level of oxygen in the water and irritate 
the gills of prey fish in the proposed project area. However, fish in 
the proposed project area would be able to move away from and avoid the 
areas where increase turbidity may occur. Given the limited area 
affected and ability of fish to move to other areas, any effects on 
forage fish are expected to be minor or negligible.
    In summary, given the short daily duration of sound associated with 
individual pile driving events and the relatively small areas being 
affected, pile driving activities associated with the proposed actions 
are not likely to have a permanent, adverse effect on any fish habitat, 
or populations of fish species. 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. Thus, we 
conclude that impacts of the specified activities 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 the IHA, which will inform both 
NMFS' consideration of ``small numbers,'' and the negligible impact 
determinations.
    Harassment is the only type of take expected to result from these 
activities. 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 the acoustic sources (i.e., impact and vibratory driving) 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 species and 
phocids because predicted auditory injury zones are larger than for 
mid-frequency species. Auditory injury is unlikely to occur for mid-
frequency species. The proposed mitigation and monitoring measures are 
expected to minimize the severity of the taking to the extent 
practicable.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the proposed take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile 
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by TTS as, in most cases, the likelihood of 
TTS occurs at distances from the source less than those at which 
behavioral harassment is likely. TTS of a sufficient degree can 
manifest as behavioral harassment, as reduced hearing sensitivity and 
the potential reduced opportunities to detect important signals 
(conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur. CTJV's proposed 
activities include the use of continuous (vibratory pile driving) and 
impulsive (impact pile driving) sources, and therefore the RMS SPL 
thresholds of 120 and 160 dB re 1 [mu]Pa are applicable.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). CTJV's 
proposed pile driving activities includes the use of impulsive (impact 
pile driving) and non-impulsive (vibratory pile driving) sources.
    These thresholds are provided in table 4 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.

[[Page 89396]]



                     Table 4--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;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 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 are used in estimating the area ensonified above the 
acoustic thresholds, including 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. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., pile driving).
    The project includes vibratory and impact pile driving. Source 
levels for these activities are based on reviews of measurements of the 
same or similar types and dimensions of piles available in the 
literature. Source levels for each pile size and activity are presented 
in table 5. Source levels for vibratory pile removal and installation 
of piles of the same diameter are assumed to be the same. Note that 
CTJV will employ a bubble curtain during all impact and vibratory 
driving activities which NMFS assumes will reduce source levels by 5 
dB.

      Table 5--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
          Pile type               Hammer type         Peak             RMS            SSsel           Source
----------------------------------------------------------------------------------------------------------------
36-in steel pipe.............  Impact/(with 5         210/(205)       193/(188)       183/(178)  Caltrans 2015,
                                dB bubble                                                         2020.
                                curtain).
                               Vibratory/(with -      180/(175)       170/(165)  ..............  Caltrans 2015.
                                5 dB bubble
                                curtain).
----------------------------------------------------------------------------------------------------------------
Note: CTJV will incorporate bubble curtain with a 5 dB reduction for all pile driving activities.

    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
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement

    Absent site-specific acoustical monitoring with differing measured 
transmission loss, a practical spreading value of 15 is used as the 
transmission loss coefficient in the above formula. Site-specific 
transmission loss data for the PTST project area are not available; 
therefore, the default coefficient of 15 is used to determine the 
distances to the Level A harassment and Level B harassment thresholds.
    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the Technical Guidance that can be used 
to relatively simply predict an isopleth distance for use in 
conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources, such as pile driving, the optional User Spreadsheet 
tool predicts the distance at which, if a marine mammal remained at 
that distance for the duration of the activity, it would be expected to 
incur PTS. Inputs used in the optional User Spreadsheet tool are shown 
in table 6, and the resulting estimated isopleths are shown in table 7, 
as reported below.

[[Page 89397]]



                    Table 6--User Spreadsheet Inputs
------------------------------------------------------------------------
                                                36-inch steel piles
                                         -------------------------------
                                             Vibratory        Impact
------------------------------------------------------------------------
Source Level (SPL)......................         170 RMS         183 SEL
Transmission Loss Coefficient...........              15              15
Weighting Factor Adjustment (kHz).......             2.5               2
Activity Duration per day (minutes).....              30  ..............
Number of strikes per pile..............  ..............             240
Number of piles per day.................               2               2
Distance of sound pressure level                      10              10
 measurement............................
------------------------------------------------------------------------


                                              Table 7--Calculated Level A and Level B Harassment Isopleths
                                                                        [Meters]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Level A harassment zones
              Scenario              ----------------------------------------------------------------------------------------------   Level B harassment
                                               LF                      MF                      HF              Phocid pinnipeds            zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
Driving Type:
    Pile Type......................  Island 1 & 2..........  Island 1 & 2..........  Island 1 & 2.........  Island 1 & 2.........  Island 1 & 2.
36-in Impact (with Bubble Curtain):
    36-in. Steel...................  285...................  10....................  338..................  152..................  736.
36-inVibratory (with Bubble
 Curtain):
    36-in. Steel...................  8.....................  1.....................  12...................  5....................  10,000.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations as well as how the information 
provided is synthesized to produce a quantitative estimate of the take 
that is reasonably likely to occur and proposed for authorization. 
Several approaches were utilized to estimate take for affected species 
depending on the best data that was available. For some species, survey 
or observational data was used to estimate take (e.g., harbor seal, 
gray seal). If density data was available, it was employed to develop 
the take estimate (i.e., bottlenose dolphin). In cases where the best 
available information consisted only of very low density values, NMFS 
assumed the average group to arrive at an estimate (i.e., humpback 
whale, harbor porpoise).

Humpback Whale

    Humpback whales are rare in the Chesapeake Bay. Density data for 
this species within the project vicinity were not available. 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 showed a maximum monthly density of 0.107/100 km\2\ 
in March. Because humpback whale occurrence is low, as mentioned above, 
the CTJV estimated, and NMFS concurred, that there will be a single 
humpback sighting every two months for the duration of in-water pile 
driving activities. There are 5 months of planned in-water 
construction. Using an average group size of two animals Kraus et al. 
(2016) and 5 months of active in-water pile driving work (Jan, Feb, 
Mar, Apr, Dec) provides an estimate of four takes during the January-
April period. NMFS conservatively assumed that there would be an 
additional sighting of 2 humpback whales in December. Because it is 
expected that a full shutdown can occur before the mammal can reach the 
full extent of the Level A harassment zone, no takes by Level A 
harassment were requested or are expected. Therefore, NMFS proposes to 
authorize six takes of humpback whale by Level B harassment.

Bottlenose Dolphin

    There was insufficient monitoring data available from previous PTST 
IHAs to estimate dolphin take. Therefore, the expected number of 
bottlenose dolphins 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). 
This report provides seasonal densities of bottlenose dolphins for 
inshore areas in the vicinity of the project and along the coast of 
Virginia Beach. Like most wildlife, bottlenose dolphins do not use 
habitat uniformly. The heterogeneity in available habitat, dietary 
items and protection likely results in some individuals preferring 
ocean and others estuary (Ballance 1992; Gannon and Waples 2004). 
Dolphins clearly 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 within the project area. A spatially refined 
approach was used by plotting dolphin sightings within a 12 km radius 
of the proposed project location. Densities were determined following 
methodology outlined in Engelhaupt et al. 2016 and Miller et al. 2019 
using the package DISTANCE in R statistical software (R. Core Team 
2018). Calculated densities by season are provided in table 8.

Table 8--Densities (Individual/km\2\) of Bottlenose Dolphin From Inshore
                            Areas of Virginia
------------------------------------------------------------------------
                                                          12 km distance
                         Season                             around PTST
                                                           project area
------------------------------------------------------------------------
Spring..................................................            1.00
Winter..................................................            0.63
------------------------------------------------------------------------

    This information was then used to calculate the monthly takes based 
on the number of pile driving days per month. These were broken out by 
month as

[[Page 89398]]

shown in table 9. The Level B harassment area for each pile and driving 
type was multiplied by the appropriate seasonal density and the 
anticipated number of days per activity per month to derive the total 
number of takes for each activity. Given this information, NMFS is 
proposing to authorize a total of 12,256 Level B harassment exposures 
for bottlenose dolphins. No take by Level A harassment is proposed by 
NMFS since the shutdown zone is 30 m and should be readily visible to 
PSOs.

                      Table 9--Estimated Takes of Bottlenose Dolphin by Level B Harassment by Month, Location, and Driving Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Month                                 Jan             Feb             Mar             Apr             Dec           Totals
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dolphin Density (/km\2\)................................            0.63            0.63               1               1            0.63  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                   Impact: Portal Island 1 Mooring Dolphins (9 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)...................................            1.38            1.38            1.38            1.38            1.38  ..............
Driving Days............................................               2               3               0               0               0  ..............
Dolphin Harassments.....................................               2               3               0               0               0               5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Vibratory: Portal Island 1 Mooring Dolphins (9 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)...................................             212             212             212             212             212  ..............
Driving Days............................................               2               3               0               0               0  ..............
Dolphin Harassments.....................................             268             401               0               0               0             669
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                   Impact: Portal Island 2 Mooring Dolphins (18 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)...................................            1.32            1.32            1.32            1.32            1.32  ..............
Driving Days............................................               0               0               0               0               9  ..............
Dolphin Harassments.....................................               0               0               0               0               8               8
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                 Vibratory: Portal Island 2 Mooring Dolphins (18 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)...................................             202             202             202             202             202  ..............
Driving Days............................................               0               0               0               0               9  ..............
Dolphin Harassments.....................................               0               0               0               0            1146            1146
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                 Impact: Portal Island 1 Trestle/Dock Removal (97 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)...................................            1.38            1.38            1.38            1.38            1.38  ..............
Driving Days............................................              13              15              13               8               0  ..............
Dolphin Harassments.....................................              12              14              18              12               0              56
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Vibratory: Portal Island 1 Trestle/Dock Removal (97 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)...................................             212             212             212             212             212  ..............
Driving Days............................................              13              15              13               8               0  ..............
Dolphin Harassments.....................................            1737            2004            2756            1696               0            8193
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                   Impact: Portal Island 2 Trestle Removal (34 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)...................................            1.32            1.32            1.32            1.32            1.32  ..............
Driving Days............................................               0               0               0               0              17  ..............
Dolphin Harassments.....................................               0               0               0               0              15              15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Vibratory: Portal Island 2 Trestle Removal (34 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)...................................             202             202             202             202             202  ..............
Driving Days............................................               0               0               0               0              17  ..............
Dolphin Harassments.....................................               0               0               0               0            2164            2164
                                                         -----------------------------------------------------------------------------------------------
    Total...............................................  ..............  ..............  ..............  ..............  ..............          12,256
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The total number of bottlenose dolphin Level B harassment events 
will be split between three bottlenose dolphin stocks: Western North 
Atlantic Southern Migratory Coastal; Western North Atlantic Northern 
Migratory Coastal; and NNCES. There is insufficient information to 
apportion the requested takes precisely to each of these three stocks 
present in the project area. Given that most of the NNCES stock are 
found in the Pamlico Sound estuarine system, it is assumed that no 
greater than 200 of the takes will be from this stock. Since members of 
the Western North Atlantic Northern Migratory Coastal and Western North 
Atlantic Southern Migratory Coastal stocks are thought to occur in or 
near the project area in greater numbers, we conservatively assume that 
no more than half of the remaining animals will belong to either of 
these stocks. Additionally, a subset of these takes would likely be 
comprised of Chesapeake Bay resident dolphins, although the size of 
that population is unknown. It is assumed that an animal will be taken 
once over a 24-hour period; however, the same individual

[[Page 89399]]

may be taken multiple times over the duration of the project. 
Therefore, the number of takes for each stock is assumed to 
overestimate the actual number of individuals that may be affected.

Harbor Porpoise

    Harbor porpoises are known to occur in the coastal waters near 
Virginia Beach (Hayes et al. 2019), and although they have been 
reported on rare occasions in the Chesapeake Bay near the project area, 
they have not been seen by the Protected Species Observers in the PTST 
project area during the construction. Density data for this species 
within the project vicinity do not exist or were not calculated because 
sample sizes were too small to produce reliable estimates of density. 
Additionally, harbor porpoise sighting data collected by the U.S. Navy 
near Naval Station Norfolk and Virginia Beach from 2012 to 2015 
(Engelhaupt et al. 2014, 2015, 2016) did not produce high enough sample 
sizes to calculate densities.
    One group of two harbor porpoises was seen during spring 2015 
(Engelhaupt et al. 2016). Therefore, it is assumed that there are two 
harbor porpoises exposed to noise exceeding harassment levels each 
month during the spring (March-April) for a total of four harbor 
porpoises (i.e., 1 group of 2 individuals per month x 2 months per year 
= 4 harbor porpoises). Harbor porpoises are not expected to be present 
in the summer, fall or winter. Harbor porpoises are members of the 
high-frequency hearing group which would have Level A harassment 
isopleths as large as 338 m during impact driving of 36'' steel pile, 
while the Level B harassment zone is 736 m. Given the relatively large 
Level A harassment zones for HF cetaceans during impact driving and a 
required shutdown zone of 200 m, NMFS will assume that 30 percent of 
porpoises are taken by Level A harassment. Therefore, NMFS proposes to 
authorize take of three porpoises by Level B harassment and one 
porpoise by Level A harassment.

Harbor Seal

    The expected number of harbor seals in the project area was 
estimated using systematic, land and vessel-based survey data for in-
water and hauled-out seals collected by the U.S. Navy at the CBBT rock 
armor and Portal Islands from November 2014 through April 2022 (Rees et 
al. 2016; Jones et al. 2018; Jones and Rees 2020; Jones and Rees 2021; 
Jones and Rees 2022; Jones and Rees 2023) and shown in table 10. The 
number of harbor seals sighted by month ranged from 0 to 170 
individuals.

                                      Table 10--Summary of Historical Harbor Seal Sightings by Month From 2014 to 2022 at the Chesapeake Bay Bridge Tunnel
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                                                       Monthly
                             Month                                  2014         2015         2016         2017         2018         2019         2020         2021         2022       average
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
January.......................................................  ...........  ...........           33          120          170            7           18           49           34         61.6
February......................................................  ...........           39           80          106          159           21            0           43           14         57.7
March.........................................................  ...........           55           61           41            0           18            6           26           37         30.5
April.........................................................  ...........           10            1            3            3            4            0            6            1          3.5
December......................................................            4            9           24            8           29            0            4           11           11         12.5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Seal counts began in November 2014 and were collected for 9 field seasons (2014/2015, 2015/2016, 2016/2017, 2017/2018, 2018/2019, 2019/2020, 2020/2021, 2021/2022) ending in 2022. In
  January 2015, no surveys were conducted.

    Seal density data are in the format of seal per unit time; 
therefore, seal take requests were calculated as total number of 
potential seals per pile driving day (8 hours) multiplied by the number 
of driving days per month. For example, in December seal density data 
is reported at 14.3 seals per day * 26 workdays in December, resulting 
in the potential of 372 instances of take for that month (table 11). 
The anticipated number of take events were summed across the months 
during which in-water pile driving is planned. The largest Level A 
harassment isopleth for phocid species is 153 m which would occur when 
piles were being removed via impact hammer with a bubble curtain. The 
smallest Level A harassment zone is 1 m which would occur when piles 
are removed via vibratory hammer with a bubble curtain. NMFS is 
proposing to require a shutdown zone for harbor seals of 160 m during 
impact driving which would theoretically result in no take by Level A 
harassment. However, a small number of harbor seals could enter into 
the shutdown zone unseen by a PSO and remain for sufficient duration to 
incur PTS. Given that harbor seals are common in the project area, NMFS 
assumed that a single harbor seal would experience Level A harassment 
during each in-water work day (80). Therefore, NMFS proposes to 
authorize the take of 80 harbor seals by Level A harassment and 2,634 
harbor seals by Level B harassment for a total of 2,714 takes (table 
11).

                            Table 11--Calculation of the Number of Harbor Seal Takes
----------------------------------------------------------------------------------------------------------------
                                                                     Estimated      Total pile     Total number
                              Month                               seals per work   driving days    of requested
                                                                        day          per month         takes
----------------------------------------------------------------------------------------------------------------
January 2024....................................................            61.6              15             924
February 2024...................................................            57.8              18           1,040
March 2024......................................................            30.5              13           396.5
April 2024......................................................             3.5               8              28
December 2024...................................................            12.5              26             325
                                                                                                           2,714
----------------------------------------------------------------------------------------------------------------

Gray Seal

    The number of gray seals expected to be present at the PTST project 
area was estimated using the same methodology as was used for the 
harbor seal. Survey data collected by the U.S. Navy at the portal 
islands from 2015 through 2022 was utilized (Rees et al. 2016; Jones et 
al. 2018; Jones and Rees 2023). A maximum of 1 gray seal was seen 
during the months of February 2015, 2016, and

[[Page 89400]]

2022. Given this information NMFS assumed that a single gray seal would 
be taken per work day in February 2024.The anticipated numbers of 
monthly takes were calculated following the same approach as for harbor 
seals, and the monthly takes were then summed (table 12). Although the 
project has not recorded any gray seal sightings to date, NMFS assumed 
that, over the duration of the project, a single gray seal could enter 
into the Level A harassment zone unseen by a PSO and remain for 
sufficient duration to incur PTS. Therefore, NMFS is proposing to 
authorize the take of 1 gray seal by Level A harassment and 17 gray 
seals by Level B harassment for a total of 18 proposed takes.

                             Table 12--Calculation of the Number of Gray Seal Takes
----------------------------------------------------------------------------------------------------------------
                                                                     Estimated      Total pile     Total number
                              Month                               seals per work   driving days    of requested
                                                                        day          per month         takes
----------------------------------------------------------------------------------------------------------------
January 2024....................................................               0              15               0
February 2024...................................................               1              18              18
March 2024......................................................               0              13               0
April 2024......................................................               0               8               0
December 2024...................................................               0              26               0
                                                                 -----------------------------------------------
    Total.......................................................  ..............  ..............              18
----------------------------------------------------------------------------------------------------------------

    Table 13 shows the take numbers proposed for authorization by NMFS 
as well as the percentage of each stock affected.

             Table 13--Proposed Take by Stock and Harassment Type as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
                                                      Level A         Level B                       Percent of
            Species                   Stock         harassment      harassment         Total           stock
----------------------------------------------------------------------------------------------------------------
Humpback Whale................  Gulf of Maine...               0               6               6             0.4
Harbor Porpoise...............  Gulf of Maine/                 1               3               4           <0.01
                                 Bay of Fundy.
Bottlenose Dolphin............  WNA Coastal,                   0           6,028           6,028            90.8
                                 Northern
                                 Migratory.
                                WNA Coastal,                   0           6,028           6,028           160.1
                                 Southern
                                 Migratory.
                                NNCES...........               0             200             200            24.3
Harbor Seal...................  Western North                 80           2,634           2,714             4.4
                                 Atlantic.
Gray Seal.....................  Western North                  1              17              18           <0.01
                                 Atlantic.
----------------------------------------------------------------------------------------------------------------

    The monitoring results from work conducted in 2020 and 2021 are 
found in table 14. The results demonstrate significantly fewer takes by 
harassment than were authorized, and it is important to note that 
estimates in the previous IHAs as well as in this proposed IHA are 
based on conservative assumptions, including the size of identified 
harassment zones and the abundance of marine mammals. However, we note 
that these assumptions represent the best available information in this 
case.

                                                          Table 14--Marine Mammal Monitoring Results From IHAs Issued in 2020 and 2021
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                              Observations  Observations                              Observations  Observations
                                                                                     Level A       Level B     in level A    in level B      Level A       Level B     in level A    in level B
                    Species                                   Stock                harassments   harassments   harassment    harassment    harassments   harassments   harassment    harassment
                                                                                   authorized    authorized    zones under   zones under   authorized    authorized    zones under   zones under
                                                                                   in 2020 IHA   in 2020 IHA    2020 IHA      2020 IHA     in 2021 IHA   in 2021 IHA    2021 IHA      2021 IHA
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback Whale................................  Gulf of Maine...................  ............            12  ............  ............  ............            12  ............  ............
Harbor Porpoise...............................  Gulf of Maine/Bay of Fundy......             5             7  ............  ............             5             7  ............  ............
Bottlenose Dolphin............................  WNA Coastal, Northern Migratory.           142        14,095  ............             5  ............        43,203  ............           394
                                                WNA Coastal, Southern Migratory.           142        14,095  ............  ............  ............        43,203  ............  ............
                                                NNCES...........................             2           198  ............  ............  ............           250  ............  ............
Harbor Seal...................................  Western North Atlantic..........         1,296         2,124  ............  ............          1154         1,730  ............  ............
Gray Seal.....................................  Western North Atlantic..........             1             3  ............  ............            16            24  ............  ............
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds,

[[Page 89401]]

and areas of similar significance, and on the availability of the 
species or stock for taking for certain subsistence uses (latter not 
applicable for this action). NMFS regulations require applicants for 
incidental take authorizations to include information about the 
availability and feasibility (economic and technological) of equipment, 
methods, and manner of conducting the activity or other means of 
effecting the least practicable adverse impact upon the affected 
species or stocks, and their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost and impact on 
operations.
    CTJV must conduct training between construction supervisors, crews, 
marine mammal monitoring team, and relevant CTJV staff prior to the 
start of all pile driving activities and when new personnel join the 
work, so that responsibilities, communication procedures, monitoring 
protocols, and operational procedures are clearly understood.
    Construction supervisors and crews, PSOs, and relevant CTJV staff 
must avoid direct physical interaction with marine mammals during 
construction activity. If a marine mammal comes within 10 m of such 
activity, operations must cease and vessels must reduce speed to the 
minimum level required to maintain steerage and safe working 
conditions, as necessary to avoid direct physical interaction. If an 
activity is delayed or halted due to the presence of a marine mammal, 
the activity may not commence or resume until either the animal has 
voluntarily exited and been visually confirmed beyond the shutdown zone 
indicated in table 15 or 15 minutes have passed without re-detection of 
the animal.
    Construction activities must be halted upon observation of a 
species for which incidental take is not authorized or a species for 
which incidental take has been authorized but the authorized number of 
takes has been met entering or within the harassment zone.
    Shutdown Zones--For all pile driving activities, CTJV would 
implement shutdowns within designated zones. The purpose of a shutdown 
zone is generally to define an area within which shutdown of the 
activity would occur upon sighting of a marine mammal (or in 
anticipation of an animal entering the defined area). Shutdown zones 
vary based on the activity type and marine mammal hearing group (table 
7). In most cases, the shutdown zones are based on the estimated Level 
A harassment isopleth distances for each hearing group. However, in 
cases where it would be challenging to detect marine mammals at the 
Level A harassment isopleth, (e.g., for high frequency cetaceans and 
phocids during impact driving activities), smaller shutdown zones have 
been proposed (table 15).

                                     Table 15--Shutdown and Monitoring Zones
                                                    [Meters]
----------------------------------------------------------------------------------------------------------------
                                                                                                    Monitoring
        Method and piles           LF cetaceans     MFcetaceans    HF cetaceans       Phocids          zone
----------------------------------------------------------------------------------------------------------------
36-in Impact (with bubble                    285              20             200             160             736
 Curtain).......................
36-in Vibratory (with bubble                  10              10              15              10          10,000
 curtain).......................
----------------------------------------------------------------------------------------------------------------

    Protected Species Observers--The number and placement of PSOs 
during all construction activities (described in the Proposed 
Monitoring and Reporting section as well as the Marine Mammal 
Monitoring Plan) would ensure that the entire shutdown zone is visible. 
A minimum of one PSO must be employed for all driving activities and 
placed at a location providing, at a minimum, adequate views of the 
established shutdown zones.
    Monitoring for Level B Harassment--PSOs would monitor the shutdown 
zones and beyond to the extent that PSOs can see. Monitoring beyond the 
shutdown zones enables observers to be aware of and communicate the 
presence of marine mammals in the project areas outside the shutdown 
zones and thus prepare for a potential cessation of activity should the 
animal enter the shutdown zone. If a marine mammal enters the Level B 
harassment zone (or Level A harassment zone if larger than the Level B 
harassment zone), PSOs will document the marine mammal's presence and 
behavior.
    Pre and Post-Activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving of 30 
minutes or longer occurs, PSOs will observe the shutdown, Level A 
harassment, and Level B harassment zones for a period of 30 minutes. 
Pre-start clearance monitoring must be conducted during periods of 
visibility sufficient for the lead PSO to determine that the shutdown 
zones are clear of marine mammals. If the shutdown zone is obscured by 
fog or poor lighting conditions, in-water construction activity will 
not be initiated until the entire shutdown zone is visible. Pile 
driving activities may commence following 30 minutes of observation 
when the determination is made that the shutdown zones are clear of 
marine mammals. If a marine mammal is observed entering or within 
shutdown zones, pile driving activities must be delayed or halted. If 
pile driving is delayed or halted due to the presence of a marine 
mammal, the activity may not commence or resume until either the animal 
has voluntarily exited and been visually confirmed beyond the shutdown 
zone or 15 minutes have passed for all other species without re-
detection of the animal.
    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 three 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

[[Page 89402]]

begins. Soft start would be implemented at the start of each day's 
impact pile driving activities and at any time following cessation of 
impact pile driving activities for a period of 30 minutes or longer. 
Soft start is not required during vibratory pile driving activities.
    Bubble Curtain--Use of a bubble curtain during impact and vibratory 
pile driving in water depths greater than 3 m (10 ft) would be 
required. It must be operated as necessary to achieve optimal 
performance, and there can be no reduction in performance attributable 
to faulty deployment. At a minimum, CTJV must adhere to the following 
performance standards: The bubble curtain must distribute air bubbles 
around 100 percent of the piling circumference for the full depth of 
the water column. The lowest bubble ring must be in contact with the 
substrate for the full circumference of the ring, and the weights 
attached to the bottom ring shall ensure 100 percent substrate contact. 
No parts of the ring or other objects shall prevent full substrate 
contact. Air flow to the bubblers must be balanced around the 
circumference of the pile.
    Based on our evaluation of the applicant's proposed measures NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.
    Visual Monitoring--Marine mammal monitoring must be conducted in 
accordance with the Marine Mammal Monitoring and Mitigation Plan. 
Marine mammal monitoring during pile driving activities must be 
conducted by NMFS-approved PSOs in a manner consistent with the 
following:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor), and have no other assigned tasks 
during monitoring periods;
     At least one PSO must have prior experience performing the 
duties of a PSO during construction activity pursuant to a NMFS-issued 
incidental take authorization;
     Other PSOs may substitute other relevant experience, 
education (degree in biological science or related field) or training 
for experience performing the duties of a PSO during construction 
activities pursuant to a NMFS-issued incidental take authorization.
     PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA.
    PSOs should also have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including 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, times, and reason for implementation 
of mitigation (or why mitigation was note implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Visual monitoring will be conducted by a minimum of one trained PSO 
positioned at a suitable vantage point that will allow coverage of the 
identified harassment zones. The Portal Islands and associated berms 
would constrain the ensonified area to only one side (i.e., east or 
west) of the bridge tunnel structure. Additionally, CTJV expressed 
concern that since they will only be using one drill for about two 
hours per week, it will be difficult to secure multiple observers 
willing to commit to the PTST project.
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after all in water construction activities. In addition, PSOs 
will record all incidents of marine mammal occurrence, regardless of 
distance from activity, and will document any behavioral reactions in 
concert with distance from piles being removed. Pile driving activities 
include the time to remove 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.

Reporting

    CTJV will submit a draft marine mammal monitoring report to NMFS 
within 90 days after the completion of pile driving activities, or 60 
days prior to a requested date of issuance of any future IHAs for the 
project, or other projects at the same location, whichever comes first. 
The marine mammal monitoring report will include an overall description 
of work completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report will include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including: (1) The number and type of piles that 
were removed (e.g., impact,

[[Page 89403]]

vibratory); and (2) Total duration of driving time for each pile 
(vibratory) and number of strikes for each pile (impact);
     PSO locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information: (1) Name of PSO who sighted the animal(s) and PSO location 
and activity at time of sighting; (2) Time of sighting; (3) 
Identification of the animal(s) (e.g., genus/species, lowest possible 
taxonomic level, or unidentified), PSO confidence in identification, 
and the composition of the group if there is a mix of species; (4) 
Distance and location of each observed marine mammal relative to the 
pile being removed for each sighting; (5) Estimated number of animals 
(min/max/best estimate); (6) Estimated number of animals by cohort 
(adults, juveniles, neonates, group composition, etc.); (7) Animal's 
closest point of approach and estimated time spent within the 
harassment zone; (8) Description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
     Number of marine mammals detected within the harassment 
zones, by species; and,
     Detailed information about implementation of any 
mitigation (e.g., shutdowns and delays), a description of specific 
actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    If no comments are received from NMFS within 30 days, the draft 
final report would constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments. The Holder must submit all 
PSO data electronically in a format that can be queried such as a 
spreadsheet or database (i.e., digital images of data sheets are not 
sufficient).
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the Holder must report the 
incident to the Office of Protected Resources (OPR), NMFS 
([email protected] and [email protected]) and to the 
Greater Atlantic Regional Stranding Coordinator (978-282-8478) as soon 
as feasible. If the death or injury was clearly caused by the specified 
activity, the Holder must immediately cease the activities until NMFS 
OPR is able to review the circumstances of the incident and determine 
what, if any, additional measures are appropriate to ensure compliance 
with the terms of this IHA. The Holder must not resume their activities 
until notified by NMFS. The report must include the following 
information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the majority of our analysis applies to all 
the species listed in table 13, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, they are described independently in the analysis below.
    Impact and vibratory pile driving have the potential to disturb or 
displace marine mammals. Specifically, the project activities may 
result in take, in the form of Level A and Level B harassment from 
underwater sounds generated from pile driving.
    The takes from Level A and Level B harassment would be due to 
potential behavioral disturbance, TTS, and PTS. No serious injury or 
mortality is anticipated given the nature of the activity and measures 
designed to minimize the possibility of injury to marine mammals. The 
potential for harassment is minimized through the construction method 
and the implementation of the planned mitigation measures (see Proposed 
Mitigation section).
    We anticipate that harbor porpoises, harbor seals and gray seals 
may sustain some limited Level A harassment in the form of auditory 
injury. However, animals in these locations 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 would lose a few decibels in its 
hearing sensitivity, which in most cases is not likely to meaningfully 
affect its ability to forage and communicate with conspecifics. Impacts 
to individual fitness, reproduction, or survival are unlikely. 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

[[Page 89404]]

sufficient notice through use of soft start.
    Behavioral responses of marine mammals to pile driving at the 
project site, if any, are expected to be mild and temporary. Marine 
mammals within the Level B harassment zone may not show any visual cues 
they are disturbed by activities or could become alert, avoid the area, 
leave the area, or display other mild responses that are not observable 
such as changes in vocalization patterns. Given the short duration of 
noise-generating activities per day, any harassment would be temporary. 
There are no other areas or times of known biological importance for 
any of the affected species.
    We acknowledge the existence and concern about the ongoing humpback 
whale UME. We have no evidence that this project is likely to result in 
vessel strikes (a major correlate of the UME) and marine construction 
projects in general involve the use of slow-moving vessels, such as 
tugs towing or pushing barges, or smaller work boats maneuvering in the 
vicinity of the construction project. These vessel types are not 
typically associated with vessel strikes resulting in injury or 
mortality. More generally, the UME does not yet provide cause for 
concern regarding population-level impacts for humpback whales. Despite 
the UME, the West Indies breeding population or DPS, remains healthy.
    For all species and stocks, take would occur within a limited, 
confined area (adjacent to the CBBT) of the stock's range and the 
amount of take proposed to be authorized is extremely small when 
compared to stock abundance. In addition, it is unlikely that minor 
noise effects in a small, localized area of habitat would have any 
effect on the stocks' ability to recover. In combination, we believe 
that these factors, as well as the available body of evidence from 
other similar activities, demonstrate that the potential effects of the 
specified activities will have only minor, short-term effects on 
individuals. The specified activities are not expected to impact rates 
of recruitment or survival and will therefore not result in population-
level impacts.
    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 serious injury or mortality is anticipated or 
authorized;
     Authorized Level A harassment would be very small amounts 
and of low degree;
     No important habitat areas have been identified within the 
project area;
     For all species, the specified project area in Chesapeake 
Bay is a very small and peripheral part of their range;
     CTJV would implement mitigation measures such as bubble 
curtains, soft-starts, and shut downs; and
     Monitoring reports from similar work in Chesapeake Bay 
have documented little to no effect on individuals of the same species 
impacted by the specified activities.
    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 previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is less than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The amount of take NMFS proposes to authorize is below one third of 
the estimated stock abundance for humpback whale, harbor porpoise, gray 
seal, and harbor seal (in fact, take is no more than 6 percent of the 
abundance of the affected stocks, see table 13). This is likely a 
conservative estimate because they assume all takes are of different 
individual animals which is likely not the case. Some individuals may 
return multiple times in a day, but PSOs would count them as separate 
takes if they cannot be individually identified.
    There are three bottlenose dolphin stocks that could occur in the 
project area. Therefore, the estimated 12,256 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 
no more than 200 takes from the NNCES stock, representing 24.3 percent 
of that population, 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 Chesapeake Bay. The 
majority of both stocks are likely to be found widely dispersed across 
their respective habitat 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

[[Page 89405]]

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 (~2 
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 and enter into the Bay. However, recent evidence 
suggests that there is likely a small resident community of NNCES 
dolphins of indeterminate size that inhabits the Chesapeake Bay year-
round (Eric Patterson, Personal Communication).
    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, Personal 
Communication). Similarly, using available photo-identification data, 
Engelhaupt et al. (2016) determined that specific individuals were 
often observed in close proximity to their original sighting locations 
and were observed multiple times in the same season or same year. 
Ninety-one percent of re-sighted individuals (100 of 110) in the study 
area were recorded less than 30 km from the initial sighting location. 
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 authorized for take 
comprises less than 10 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;
     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 would 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

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

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to CTJV for conducting construction activities as part of 
the PTST project near Virginia Beach, VA from January through December 
2024 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

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 
construction activities associated with the PTST project. We also 
request comment on the potential renewal of this proposed IHA as 
described in the paragraph below. Please include with your comments any 
supporting data or literature citations to help inform decisions on the 
request for this IHA or a subsequent renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, 1-year renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical activities as described in the Description of Proposed 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond 1 year from expiration 
of the initial IHA).
     The request for renewal must include the following:

[[Page 89406]]

    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    Upon review of the request for renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS determines 
that there are no more than minor changes in the activities, the 
mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: December 21, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-28514 Filed 12-26-23; 8:45 am]
BILLING CODE 3510-22-P