Notice2024-05321
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel Project, Virginia Beach, Virginia
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
March 13, 2024
Effective
February 15, 2024
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
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.
Full Text
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<title>Federal Register, Volume 89 Issue 50 (Wednesday, March 13, 2024)</title>
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[Federal Register Volume 89, Number 50 (Wednesday, March 13, 2024)]
[Notices]
[Pages 18378-18393]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. 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).
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[[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; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a> and
2023 Draft SARS; <a href="https://www.federalregister.gov/documents/2024/01/29/2024-01653/draft-2023-marine-mammal-stock-assessment-reports">https://www.federalregister.gov/documents/2024/01/29/2024-01653/draft-2023-marine-mammal-stock-assessment-reports</a>) and more
general information about these species (e.g., physical and behavioral
descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
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; <a href="https://www.federalregister.gov/documents/2024/01/29/2024-01653/draft-2023-marine-mammal-stock-assessment-reports">https://www.federalregister.gov/documents/2024/01/29/2024-01653/draft-2023-marine-mammal-stock-assessment-reports</a>. All
values presented in table 2 are the most recent available at the time
of publication and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports</a>. 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 (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>) 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:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> 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);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> 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:
<bullet> PSOs must be independent of the activity contractor (for
example, employed by a subcontractor), and have no other assigned tasks
during monitoring periods;
<bullet> 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;
<bullet> 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.
<bullet> PSOs must be approved by NMFS prior to beginning any
activity subject to this IHA.
PSOs should also have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> 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
<bullet> 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:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> 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);
[[Page 18391]]
<bullet> PSO locations during marine mammal monitoring;
<bullet> 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;
<bullet> 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);
<bullet> Number of marine mammals detected within the harassment
zones, by species; and,
<bullet> 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
(<a href="/cdn-cgi/l/email-protection#f7a7a5d9bea3a7d9ba98999e8398859e9990a5928798858384b799989696d9909881"><span class="__cf_email__" data-cfemail="8fdfdda1c6dbdfa1c2e0e1e6fbe0fde6e1e8ddeaffe0fdfbfccfe1e0eeeea1e8e0f9">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#f4bda0a4da849581989d9a91b49a9b9595da939b82"><span class="__cf_email__" data-cfemail="d8918c88f6a8b9adb4b1b6bd98b6b7b9b9f6bfb7ae">[email protected]</span></a>) 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:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> 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
[[Page 18392]]
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:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> Authorized Level A harassment will be very small amounts
and of low degree;
<bullet> No important habitat areas have been identified within the
project area;
<bullet> For all species, the specified project area in Chesapeake
Bay is a very small and peripheral part of their range;
<bullet> CTJV will implement mitigation measures such as bubble
curtains, soft-starts, and shut downs; and
<bullet> 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:
<bullet> 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);
<bullet> Potential bottlenose dolphin takes in the project area are
likely to be allocated among three distinct stocks;
<bullet> 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;
<bullet> 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;
<bullet> 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
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