[Federal Register Volume 89, Number 50 (Wednesday, March 13, 2024)]
[Notices]
[Pages 18378-18393]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-05321]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD721]


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: Issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
the Chesapeake Tunnel Joint Venture (CTJV) to incidentally harass 
marine mammals during construction associated with the Parallel Thimble 
Shoal Tunnel Project (PTST) in Virginia Beach, Virginia.

DATES: This authorization is effective from February 15, 2024, through 
February 14, 2025.

ADDRESSES: 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 below.

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

[[Page 18379]]

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

Summary of Request

    On 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 final IHA will 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 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 
will 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 planned 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. Planned 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 installation activities are planned by 
CTJV.
    The in-water removal of a total of 158 piles will 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. The IHA is effective 
from February 15, 2024, through February 14, 2025.
BILLING CODE 3510-22-P

[[Page 18380]]

[GRAPHIC] [TIFF OMITTED] TN13MR24.004

BILLING CODE 3510-22-C

                                      Table 1--Anticipated Pile Installation Schedule (January 2024-December 2024)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                             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
--------------------------------------------------------------------------------------------------------------------------------------------------------
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).
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 18381]]

    A detailed description of the planned construction project is 
provided in the Federal Register notice for the proposed IHA (88 FR 
89385, December 27, 2023). Since that time, no changes have been made 
to the planned activities. Therefore, a detailed description is not 
provided here. Please refer to that Federal Register notice for the 
description of the specific activity.
    Mitigation, monitoring, and reporting measures are described in 
detail later in this document (please see Mitigation and Monitoring and 
Reporting).

Comments and Responses

    A notice of NMFS' proposal to issue an IHA to CTJV was published in 
the Federal Register on December 27, 2023 (88 FR 89385). That notice 
described, in detail, CTJV's activities, the marine mammal species that 
may be affected by the activities, and the anticipated effects on 
marine mammals. In that notice, we requested public input on the 
request for authorization described therein, our analyses, the proposed 
authorization, and any other aspect of the notice of proposed IHA, and 
requested that interested persons submit relevant information, 
suggestions, and comments. This proposed notice was available for a 30-
day public comment period. No comments were submitted during the 30-day 
public comment period,

Changes From the Proposed IHA to Final IHA

    Since the Federal Register notice of the proposed IHA was published 
(88 FR 89385, December 27, 2023), NMFS published the 2023 Draft 
Atlantic Marine Mammal Stock Assessment Report, which provide updates 
to the harbor porpoise Gulf of Maine/Bay of Fundy stock and the gray 
seal Western North Atlantic stock abundances, Potential Biological 
Removal values (PBRs), and Annual Mortality/Serious Injury values 
(Annual M/SI). Updates have been made to Table 2 Species Likely 
Impacted by the Specified Activities as well as to our analysis of take 
(see Estimated Take) and small numbers determinations (see Small 
Numbers).

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 
2023 Draft SARS;  https://www.federalregister.gov/documents/2024/01/29/2024-01653/draft-2023-marine-mammal-stock-assessment-reports) 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 
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 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) and 
2023 Draft SARS;  https://www.federalregister.gov/documents/2024/01/29/2024-01653/draft-2023-marine-mammal-stock-assessment-reports. 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
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock            strategic (Y/N)      Nmin, most recent       PBR      Annual M/
                                                                                               \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
    Humpback whale..................  Megaptera novaeangliae.  Gulf of Maine..........  -,-; N             1,393 (0; 1,375, 2016)         22       12.15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Bottlenose dolphin..............  Tursiops truncatus.....  WNA Coastal, Northern    -,-; Y             6,639 (0.41; 4,759;            48   12.2-21.5
                                                                Migratory.                                  2016).
                                                               WNA Coastal, Southern    -,-; Y             3,751 (0.06; 2,353;            24      0-18.3
                                                                Migratory.                                  2016).
                                                               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            85,765 (0.53, 56,420,         649         145
                                                                Fundy.                                      2021).
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 18382]]

 
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  WNA....................  -, -; N            61,336 (0.08, 57,637,       1,729         339
                                                                                                            2018).
    Gray seal \4\...................  Halichoerus grypus.....  WNA....................  -, -; N            27,911 (0.0, 23,624,        1,512       4,570
                                                                                                            2021).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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).

    A detailed description of the species likely to be affected by the 
construction project, including a brief introduction to the affected 
stock as well as available information regarding population trends and 
threats, and information regarding local occurrence, were provided in 
the Federal Register notice for the proposed IHA (88 FR 89385, December 
27, 2023). Please refer to the Federal Register notice of the proposed 
IHA for the full description for all species. Please also refer to 
NMFS' website (https://www.fisheries.noaa.gov/find-species) for 
generalized species accounts.

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

    The underwater noise produced by CTJV's construction activities has 
the potential to result in behavioral harassment of marine mammals in 
the vicinity of the survey area. The Federal Register notice of the 
proposed IHA (88 FR 89385, December 27, 2023) included a discussion of 
the effects of anthropogenic noise on marine mammals and the potential 
effects of underwater noise from CTJV's construction activities on 
marine mammals and their habitat. That information and analysis is 
incorporated by reference into this final IHA determination and is not 
repeated here; please refer to the notice of the

[[Page 18383]]

proposed IHA (88 FR 89385, December 27, 2023).

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized 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 will 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 required 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 authorized for this activity. Below we describe how the 
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 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 planned 
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 
planned 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.

                     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.

[[Page 18384]]

 
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 planned 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 removal 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.

                    Table 6--User Spreadsheet Inputs
------------------------------------------------------------------------
                                                36-inch steel piles
                                         -------------------------------
                                             Vibratory        Impact
------------------------------------------------------------------------
Source Level (SPL)......................         170 RMS         183 SEL

[[Page 18385]]

 
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-in Vibratory (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 authorized for take. 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 will 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 authorized. Therefore, NMFS has 
authorized 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 planned 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 shown in table 9. The Level B harassment area for each pile 
and driving type was multiplied by the

[[Page 18386]]

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 authorizing 12,256 Level B 
harassment exposures for bottlenose dolphins. No take by Level A 
harassment has been authorized by NMFS since the shutdown zone is 20 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           1,146           1,146
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                 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.....................................           1,737           2,004           2,756           1,696               0           8,193
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                   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           2,164           2,164
                                                         -----------------------------------------------------------------------------------------------
    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 will 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 may be taken multiple times 
over the duration of the project. Therefore, the number of takes

[[Page 18387]]

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 will 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 is 
authorizing 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 x 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 will occur when 
piles are being removed via impact hammer with a bubble curtain. The 
smallest Level A harassment zone is 1 m which will occur when piles are 
removed via vibratory hammer with a bubble curtain. NMFS is requiring a 
shutdown zone for harbor seals of 100 m during impact driving which 
will 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 will experience Level A harassment during each in-water 
work day (80). Therefore, NMFS is authorizing 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 2022. Given this 
information NMFS

[[Page 18388]]

assumed that a single gray seal will 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 authorizing the take of 1 gray seal by Level A 
harassment and 17 gray seals by Level B harassment for a total of 18 
authorized 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 authorized by NMFS as well as the 
percentage of each stock affected.

            Table 13--Authorized 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           160.7
                                 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 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  ............  ............         1,154         1,730  ............  ............
Gray Seal.....................................  Western North Atlantic..........             1             3  ............  ............            16            24  ............  ............
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Mitigation

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

[[Page 18389]]

(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 will 
implement shutdowns within designated zones. The purpose of a shutdown 
zone is generally to define an area within which shutdown of the 
activity will 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 established (table 15).

                                     Table 15--Shutdown and Monitoring Zones
                                                    [Meters]
----------------------------------------------------------------------------------------------------------------
                                                                                                    Monitoring
        Method and piles           LF cetaceans    MF cetaceans    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 Monitoring and 
Reporting section as well as the Marine Mammal Monitoring Plan) will 
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 will 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 
will 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 will be conducted a total of three times 
before impact pile driving begins. Soft start will be implemented at 
the start of each day's impact pile driving activities and at any time 
following cessation of

[[Page 18390]]

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) will 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 planned measures, NMFS 
has determined that the 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.

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 
will 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, vibratory); and (2) Total duration of 
driving time for each pile (vibratory) and number of strikes for each 
pile (impact);

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     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 will 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 
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 will 
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 will 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 will be likely to move 
away from a sound source that represents an aversive stimulus, 
especially at levels that would be expected to result in PTS, given 
sufficient notice through use of soft start.
    Behavioral responses of marine mammals to pile driving at the 
project

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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 will occur within a limited, 
confined area (adjacent to the CBBT) of the stock's range and the 
amount of take 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 will 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 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 will 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 will 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 required monitoring and 
mitigation measures, NMFS finds that the total marine mammal take from 
the planned activity will have a negligible impact on all affected 
marine mammal species or stocks.

Small Numbers

    As noted 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 is authorizing 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 will 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 will 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 will 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 (90.8 percent) and southern migratory coastal stocks (160.7 
percent). Based on consideration of various factors described below, we 
have determined the numbers of individuals taken will 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 
will 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 located in the vicinity of the Bay for

[[Page 18393]]

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 will 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 will considerably reduce the 
number of individual animals that are taken by harassment. Furthermore, 
the existence of a resident dolphin population in the Bay will 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 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 will 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 will be unlikely to find a high 
percentage of any stock concentrated at such boundaries;
     Many of the takes will 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 planned activity 
(including the required mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS finds that small numbers of 
marine mammals will be taken relative to the population size of the 
affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks will 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 expected to result from 
this activity or been authorized by NMFS. Therefore, NMFS has 
determined that formal consultation under section 7 of the ESA is not 
required for this action.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our action (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 will preclude this 
categorical exclusion. Accordingly, NMFS has determined that the 
issuance of the IHA qualifies to be categorically excluded from further 
NEPA review.

Authorization

    NMFS has issued an IHA to CTJV for the potential harassment of 
small numbers of five marine mammal species incidental to the Parallel 
Thimble Shoal Tunnel Project, In Virginia Beach, Virginia that includes 
the previously explained mitigation, monitoring and reporting 
requirements.

    Dated: March 4, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-05321 Filed 3-12-24; 8:45 am]
BILLING CODE 3510-22-P