Notice2023-28514
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
December 27, 2023
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the Chesapeake Tunnel Joint Venture (CTJV) for authorization to take marine mammals incidental to the Parallel Thimble Shoal Tunnel Project (PTST) in Virginia Beach, Virginia. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 88 Issue 247 (Wednesday, December 27, 2023)</title>
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[Federal Register Volume 88, Number 247 (Wednesday, December 27, 2023)]
[Notices]
[Pages 89385-89406]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-28514]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XD544]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel
Project, Virginia Beach, Virginia
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the Chesapeake Tunnel Joint
Venture (CTJV) for authorization to take marine mammals incidental to
the Parallel Thimble Shoal Tunnel Project (PTST) in Virginia Beach,
Virginia. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to issue an incidental harassment
authorization (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time, 1-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
[[Page 89386]]
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision.
DATES: Comments and information must be received no later than January
26, 2024.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
<a href="/cdn-cgi/l/email-protection#a2ebf6f28cd2c3d7cecbccc7e2cccdc3c38cc5cdd4"><span class="__cf_email__" data-cfemail="c9809d99e7b9a8bca5a0a7ac89a7a6a8a8e7aea6bf">[email protected]</span></a>. 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 above.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at <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> without change. All
personal identifying information (e.g., name, address) voluntarily
submitted by the commenter may be publicly accessible. Do not submit
confidential business information or otherwise sensitive or protected
information.
FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NAO 216-6A, which do not
individually or cumulatively have the potential for significant impacts
on the quality of the human environment and for which we have not
identified any extraordinary circumstances that would preclude this
categorical exclusion. Accordingly, NMFS has preliminarily determined
that the issuance of the proposed IHA qualifies to be categorically
excluded from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On July 28, 2023, NMFS received a request from CTJV for an IHA to
take marine mammals incidental to in-water construction activities
associated with the PTST project near Virginia Beach, VA. Following
NMFS' review of the initial application, CTJV submitted several revised
versions of the application based on NMFS' comments. The final version
was submitted on November 7, 2023, and was deemed adequate and complete
on November 13, 2023. CTJV's request is for take of 5 species by Level
B harassment and, for a subset of three of these species, by Level A
harassment. Neither CTJV nor NMFS expect serious injury or mortality to
result from this activity and, therefore, an IHA is appropriate.
NMFS most recently issued an IHA to CTJV for similar work on
November 8, 2022, (87 FR 68462; November 15, 2022). CTJV complied with
all the requirements (e.g., mitigation, monitoring, and reporting) of
the previous IHA, and information regarding their monitoring results
may be found in the Estimated Take section.
This proposed IHA would cover 1 year of a larger project for which
CTJV obtained IHAs for similar work (83 FR 36522, July 30, 2018; 85 FR
16061, March 20, 2020; 86 FR 14606, March 17, 2021; 86 FR 67024,
November 24, 2021; and 87 FR 68462, November 15, 2022). The larger
multi-year PTST project consists of the construction of a two-lane
parallel tunnel to the west of the existing Thimble Shoal Tunnel,
connecting Portal Island Nos. 1 and 2 as part of the 23-mile Chesapeake
Bay Bridge-Tunnel (CBBT) facility.
Description of Proposed Activity
Overview
The purpose of the project is to build an additional two lane
vehicle tunnel under the navigation channel as part of the CBBT. The
PTST project will address existing constraints to regional mobility
based on current traffic volume, improve safety, improve the ability to
conduct necessary maintenance with minimal impact to traffic flow, and
ensure reliable hurricane evacuation routes. In-water construction work
would include the removal of a total of 158 36-inch steel piles on the
temporary dock and trestle on Portal Islands Nos. 1 and 2 as well as
the removal of steel mooring piles on both Portal Islands (97 total on
Portal Island No.1); the removal of 36'' steel piles on the trestle (34
total on Portal Island No. 2); and the removal of 36'' steel mooring
piles on both Island 1 (9 piles) and Island No. 2 (18 piles). All steel
piles are hollow pipe piles. The proposed impact and vibratory pile
removal activities can introduce sound into the water environment which
can result in take of marine mammals by behavioral harassment and, for
some species, by auditory injury. Proposed construction activities are
expected to be completed from January-April as well as in December
2024. Note that the term ``pile driving'' is only used to refer to pile
removal activities. No pile
[[Page 89387]]
installation activities are planned by CTJV.
Dates and Duration
The proposed in-water removal of a total of 158 piles would occur
over 80 days. Removal will begin on Portal Island No. 1 in January
through April 2024 for 54 days then will resume on Portal Island No. 2
in December 2024 for 26 days. No pile removal work will take place in
the interim. The project schedule is shown in table 1.
Specific Geographic Region
The PTST project is located between Portal Islands No.1 and No. 2
of the CBBT as shown in Figure 1. A 6,525 lineal foot (ft) (1,989
meters(m)) tunnel will be bored underneath the Thimble Shoal Channel
connecting the Portal Islands located near the mouth of the Chesapeake
Bay. The CBBT is a 23-mile (37 km) long facility that connects the
Hampton Roads area of Virginia to the Eastern Shore of Virginia. Water
depths within the PTST construction area range from 0 to 60 ft (18.2 m)
below Mean Lower Low Water (MLLW). The Thimble Shoal Channel is 1,000
ft (305 m) wide and is maintained at a depth of 50 ft (15.2 m) MLLW.
[GRAPHIC] [TIFF OMITTED] TN27DE23.003
Figure 1--Map of Proposed Project Area Near Virginia Beach, Virginia
Detailed Description of the Specified Activity
The PTST project consists of the construction of a two lane tunnel
parallel and to the west of the existing tunnel, connecting Portal
Islands No. 1 and No. 2. A tunnel boring machine (TBM) will both
excavate material and construct the tunnel as it progresses from Portal
Island No. 1 to Portal Island No. 2. Precast concrete tunnel segments
will be transported to the TBM for installation. The TBM will assemble
the tunnel segments in-place as the tunnel is bored. After the tunnel
structure is completed, final upland work for the PTST Project will
include installation of the final roadway, lighting, finishes,
mechanical systems, and other required internal systems for tunnel use
and function. In addition, the existing fishing pier will be repaired
and refurbished.
[[Page 89388]]
Descriptions of additional upland activities may be found in the
application but such actions will not affect marine mammals and are not
described here.
Proposed in-water activities during this IHA include the removal of
36-inch steel piles on the temporary dock and trestle (97 total on
Portal Island No.1) and the removal of 36-inch steel piles on the
trestle (34 total on Portal Island No.2) as well as the removal of 36-
inch steel mooring piles on both Portal Islands (9 piles on Portal
Island No. 1 and 18 total on Portal Island No. 2). A total of 158 piles
will be removed over 80 in-water work days. Pile driving activities
will be conducted by initially using an impact hammer, if necessary, to
break the friction on the previously installed piles. If an impact
hammer is not required to initially break friction, then a vibratory
hammer will be used for extraction. If the pile cannot be removed with
this method, the pile will then be cut off a minimum of three feet
below the stabilized, post construction sediment-water interface. There
will be no concurrent pile driving activity.
Table 1--Anticipated Pile Installation Schedule
[January 2024-December 2024]
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Number of Number of piles/
Installation/ Bubble curtain Number days per days per Anticipated
Pile location Pile function Pile type removal method (yes/no) of piles activity activity (per installation
(total) hammer type) date
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Portal Island No. 1......... Mooring 36-inch Impact (if Yes............ 9 5 (2 Piles/Day).. 1 January
dolphins. Diameter Steel needed). Yes............ 5 (2 Piles/Day).. through 28
Pipe Pile. Vibratory February 2024.
(Removal).
Portal Island No. 1......... Temporary Dock/ 36-inch Impact (if Yes............ 97 49 (2 Piles/Day).. 1 January
Trestle. Diameter Steel needed). Yes............ 49 (2 Piles/Day).. through 30
Interlocked Vibratory April 2024.
Pipe Piles. (Removal).
Portal Island No. 2......... Mooring 36-inch Impact (if Yes............ 18 9 (2 Piles/Day).. December 1-31,
dolphins. Diameter Steel needed). Yes............ 9 (2 Piles/Day).. 2024.
Pipe Pile. Vibratory
(Removal).
Portal Island No. 2......... Omega Trestle.. 36-inch Impact (if Yes............ 34 17 (2 Piles/Day).. December 1-31,
Diameter Steel needed). Yes............ 17 (2 Piles/Day).. 2024.
Interlocked Vibratory
Pipe Piles. (Removal).
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Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting)
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <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
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
proposed to be authorized for this activity and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality from
anthropogenic sources are included here as gross indicators of the
status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Atlantic and Gulf of Mexico SARs (Hayes et al. 2023). All
values presented in table 2 are the most recent available at the time
of publication and are available online at: <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
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ESA/MMPA status; Stock abundance (CV, Nmin, most recent Annual M/SI
Common name Scientific name Stock Strategic (Y/N) \1\ abundance survey) \2\ PBR \3\
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals):
Humpback whale................... Megaptera novaeangliae.. Gulf of Maine.......... -,-; N................. 1,393 (0; 1,375, 2016) 22 12.15
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
[[Page 89389]]
Bottlenose dolphin............... Tursiops truncatus...... WNA Coastal, Northern -,-; Y................. 6,639 (0.41; 4,759; 2016) 48 12.2-21.5
Migratory.
WNA Coastal, Southern -,-; Y................. 3,751 (0.06; 2,353; 2016) 24 0-18.3
Migratory.
Northern North Carolina -,-; Y................. 823 (0.06; 782; 2017) 7.8 7.2-30
Estuarine System.
Family Phocoenidae (porpoises):
Harbor porpoise.................. Phocoena phocoena....... Gulf of Maine/Bay of -, -; N................ 95,543 (0.31; 74,034; 2016) 851 164
Fundy.
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Order Carnivora--Superfamily Pinnipedia
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Family Phocidae (earless seals):
Harbor seal...................... Phoca vitulina.......... WNA.................... -, -; N................ 61,336 (0.08, 57,637, 2018) 1,729 339
Gray seal \4\.................... Halichoerus grypus...... WNA.................... -, -; N................ 27,300 (0.22, 22,785, 2016) 1,458 4,453
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted
under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be declining and likely to be listed under
the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <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).
As indicated above, all five species (with seven managed stocks) in
table 2 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. While North Atlantic
right whale and fin whale could potentially occur in the area,
occurrence of these species is very rare, the species are readily
observed, and the applicant would shut down pile driving activity if
they enter the project area. Thus take is not expected to occur, and
they are not discussed further.
Humpback Whale
The humpback whale is found worldwide in all oceans. In winter,
humpback whales from waters off New England, Canada, Greenland,
Iceland, and Norway migrate to mate and calve primarily in the West
Indies, where spatial and genetic mixing among these groups occurs. For
the humpback whale, NMFS defines a stock on the basis of feeding
location, i.e., Gulf of Maine. However, our reference to humpback
whales in this document refers to any individuals of the species that
are found in the specific geographic region. These individuals may be
from the same breeding population (e.g., West Indies breeding
population of humpback whales) but visit different feeding areas.
Based on photo-identification only 39 percent of individual
humpback whales observed along the mid- and south Atlantic U.S. coast
are from the Gulf of Maine stock (Barco et al., 2002). Therefore, the
SAR abundance estimate underrepresents the relevant population, i.e.,
the West Indies breeding population.
Prior to 2016, humpback whales were listed under the ESA as an
endangered species worldwide. Following a 2015 global status review
(Bettridge et al., 2015), NMFS established 14 Distinct Population
Segments (DPSs) with different listing statuses (81 FR 62259, September
8, 2016) pursuant to the ESA. The West Indies DPS, which consists of
the whales whose breeding range includes the Atlantic margin of the
Antilles from Cuba to northern Venezuela, and whose feeding range
primarily includes the Gulf of Maine, eastern Canada, and western
Greenland, was delisted. As described in Bettridge et al. (2015), the
West Indies DPS has a substantial population size (i.e., approximately
10,000; Stevick et al., 2003; Smith et al., 1999; Bettridge et al.,
2015), and appears to be experiencing consistent growth.
Humpback whales are the only large cetaceans that are likely to
occur in the project area and could be found there at any time of the
year. There has been a decline in whale sightings in the peak months
since 2016/17; the distribution of whale sightings occur most
frequently in the month of January through March (Aschettino et al.,
2021).
There have been 33 humpback whale strandings recorded in Virginia
between 1988 and 2013. Most of these strandings were reported from
ocean facing beaches, but 11 were also within the Chesapeake Bay (Barco
and Swingle, 2014). Strandings occurred in all seasons, but were most
common in the spring. Since January 2016, elevated humpback whale
mortalities have occurred along the Atlantic coast from Maine through
Florida. The event has been declared an Unusual Mortality Event (UME)
with 209 strandings recorded, 7 of which occurred in or near the mouth
of the Chesapeake Bay. More detailed information is available at:
<a href="https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2023-humpback-whale-unusual-mortality-event-along-atlantic-coast">https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2023-humpback-whale-unusual-mortality-event-along-atlantic-coast</a>. Three
previous UMEs involving humpback whales have occurred since 2000, in
2003, 2005, and 2006.
Humpback whales use the mid-Atlantic as a migratory pathway to and
from the calving/mating grounds, but it may also be an important winter
feeding area for juveniles. Since 1989, observations of juvenile
humpbacks in the mid-Atlantic have been increasing during the winter
months, peaking from January through March. Biologists theorize that
non-reproductive animals may be establishing a winter feeding range in
the mid-Atlantic since they are not participating in reproductive
[[Page 89390]]
behavior in the Caribbean (Swingle et al., 1993).
Bottlenose Dolphin
The bottlenose dolphin occurs in temperate and tropical oceans
throughout the world (Blaylock 1985). In the western Atlantic Ocean
there are two distinct morphotypes of bottlenose dolphins, an offshore
type that occurs along the edge of the continental shelf as well as an
inshore type. The inshore morphotype can be found along the entire
United States coast from New York to the Gulf of Mexico, and typically
occurs in waters less than 20 m deep (Hayes et al., 2021). Bottlenose
dolphins found in Virginia are representative primarily of either the
northern migratory coastal stock, southern migratory coastal stock, or
the Northern North Carolina Estuarine System Stock (NNCES).
The northern migratory coastal stock is best defined by its
distribution during warm water months when the stock occupies coastal
waters from the shoreline to approximately the 20 m isobath between
Assateague, Virginia, and Long Island, New York (Garrison et al.,
2017). The stock migrates in late summer and fall and, during cold
water months (best described by January and February), occupies coastal
waters from approximately Cape Lookout, North Carolina, to the North
Carolina/Virginia border. Historically, common bottlenose dolphins have
been rarely observed during cold water months in coastal waters north
of the North Carolina/Virginia border, and their northern distribution
in winter appears to be limited by water temperatures. Overlap with the
southern migratory coastal stock in coastal waters of northern North
Carolina and Virginia is possible during spring and fall migratory
periods, but the degree of overlap is unknown and it may vary depending
on annual water temperature (Garrison et al., 2016). When the stock has
migrated in cold water months to coastal waters from just north of Cape
Hatteras, North Carolina, to just south of Cape Lookout, North
Carolina, it overlaps spatially with the NNCES stock (Garrison et al.,
2017).
The southern migratory coastal stock migrates seasonally along the
coast between North Carolina and northern Florida (Garrison et al.,
2017). During January-March, the southern migratory coastal stock
appears to move as far south as northern Florida. During April-June,
the stock moves back north past Cape Hatteras, North Carolina, where it
overlaps, in coastal waters, with the NNCES stock (in waters <=1 km
from shore). During the warm water months of July-August, the stock is
presumed to occupy coastal waters north of Cape Lookout, North
Carolina, to Assateague, Virginia, including the Chesapeake Bay.
The NNCES stock is best defined as animals that occupy primarily
waters of the Pamlico Sound estuarine system (which also includes Core,
Roanoke, and Albemarle sounds, and the Neuse River) during warm water
months (July-August). Members of this stock also use coastal waters
(<=1 km from shore) of North Carolina from Beaufort north to Virginia
Beach, Virginia, including the lower Chesapeake Bay. A community of
NNCES dolphins are likely year-round Bay residents (Eric Patterson,
pers. communication).
Harbor Porpoise
The harbor porpoise is typically found in colder waters in the
northern hemisphere. In the western North Atlantic Ocean, harbor
porpoises range from Greenland to as far south as North Carolina (Barco
and Swingle, 2014). They are commonly found in bays, estuaries, and
harbors less than 200 m deep (Hayes et al., 2022). Harbor porpoises in
the United States are made up of the Gulf of Maine/Bay of Fundy stock.
Gulf of Maine/Bay of Fundy stock are concentrated in the Gulf of Maine
in the summer, but are widely dispersed from Maine to New Jersey in the
winter. South of New Jersey, harbor porpoises occur at lower densities.
Migrations to and from the Gulf of Maine do not follow a defined route
(Hayes et al., 2022).
Harbor porpoise occur seasonally in the winter and spring in small
numbers near the project area. Strandings occur primarily on ocean
facing beaches, but they occasionally travel into the Chesapeake Bay to
forage and could occur in the project area (Barco and Swingle, 2014).
Since 1999, stranding incidents have ranged widely from a high of 40 in
1999 to 2 in 2011, 2012, and 2016 (Barco et al., 2017). In most areas,
harbor porpoise occur in small groups of just a few individuals.
Harbor Seal
The harbor seal occurs in arctic and temperate coastal waters
throughout the northern hemisphere, including on both the east and west
coasts of the United States. On the east coast, harbor seals can be
found from the Canadian Arctic down to Georgia (Blaylock, 1985). Harbor
seals occur year-round in Canada and Maine and seasonally (September-
May) from southern New England to New Jersey (Hayes et al., 2022). The
range of harbor seals appears to be shifting as they are regularly
reported further south than they were historically. In recent years,
they have established haulout sites in the Chesapeake Bay including on
the portal islands of the CBBT (Rees et al., 2016, Jones et al., 2018).
Harbor seals are the most common seal in Virginia (Barco and
Swingle, 2014). They can be seen resting on the rocks around the portal
islands of the CBBT from December through April. They are primarily
concentrated north of the project area at Portal Island No. 3. Over 8
field seasons (2014-2015 through 2021-2022), 79.1 percent of seals were
recorded at Portal Island No. 3; 17.4 percent were recorded at Portal
Island No. 4; and 3.5 percent were recorded at Portal Island No. 1 and
No. 2 combined (Jones and Rees 2023).
Harbor seals are central-place foragers (Orians and Pearson, 1979)
and tend to exhibit strong site fidelity within season and across
years, generally forage close to haulout sites, and repeatedly visit
specific foraging areas (Suryan and Harvey, 1998; Thompson et al.,
1998). Harbor seals tend to forage at night and haul out during the day
with a peak in the afternoon between 1 p.m. and 4 p.m. (London et al.,
2001).
Gray Seal
The gray seal occurs on both coasts of the Northern Atlantic Ocean
and are divided into three major populations The western north Atlantic
stock occurs in eastern Canada and the northeastern United States,
occasionally as far south as North Carolina. Gray seals inhabit rocky
coasts and islands, sandbars, ice shelves and icebergs. In the United
States, gray seals congregate in the summer to give birth at four
established colonies in Massachusetts and Maine (Hayes et al., 2022).
From September through May, they disperse and can be abundant as far
south as New Jersey. The range of gray seals appears to be shifting as
they are regularly being reported further south than they were
historically (Rees et al. 2016).
Gray seals are uncommon in Virginia and the Chesapeake Bay. Only 15
gray seal strandings were documented in Virginia from 1988 through 2013
(Barco and Swingle, 2014). They are rarely found resting on the rocks
around the portal islands of the CBBT from December through April
alongside harbor seals. Seal observation surveys conducted at the CBBT
recorded one gray seal in each of the 2014/2015 and 2015/2016 seasons
while no gray seals were reported during the 2016/2017 and 2017/2018
seasons (Rees et al. 2016, Jones et al. 2018).
[[Page 89391]]
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in table 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger &
L. australis).
Phocid pinnipeds (PW) (underwater) (true 50 Hz to 86 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 39 kHz.
lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al.
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take section later in this document includes a
quantitative analysis of the number of individuals that are expected to
be taken by this activity. The Negligible Impact Analysis and
Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and whether those
impacts are reasonably expected to, or reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.
Acoustic effects on marine mammals during the specified activity
can occur from impact and vibratory pile driving activities. The
effects of underwater noise from CTJV's proposed activities have the
potential to result in Level A harassment and Level B harassment of
marine mammals.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (American National Standards Institute 1995).
The sound level of an area is defined by the total acoustical energy
being generated by known and unknown sources. These sources may include
physical (e.g., waves, wind, precipitation, earthquakes, ice,
atmospheric sound), biological (e.g., sounds produced by marine
mammals, fish, and invertebrates), and anthropogenic sound (e.g.,
vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10 to 20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
Two types of hammers would be used on this project. Impact hammers
operate by repeatedly dropping and/or pushing a heavy piston onto a
pile to drive the pile into the substrate. Sound generated by impact
hammers is characterized by rapid rise times and high peak levels, a
potentially injurious combination (Hastings and Popper, 2005).
Vibratory hammers install piles by vibrating them and allowing the
weight of the hammer to push them into the sediment. Vibratory hammers
produce significantly less sound than impact hammers. Peak Sound
Pressure Levels (SPLs) may be 180 dB or greater, but are generally 10
to 20 dB lower than SPLs generated during impact pile driving of the
same-sized pile (Oestman et al., 2009). Rise time is slower, reducing
the probability and severity of injury, and sound energy is distributed
over a greater amount of time (Nedwell and Edwards, 2002; Carlson et
al., 2005).
[[Page 89392]]
The likely or possible impacts of CTJV's proposed activities on
marine mammals could be generated from both non-acoustic and acoustic
stressors. Potential non-acoustic stressors include the physical
presence of the equipment, vessels, and personnel; however, any impacts
to marine mammals are expected to primarily be acoustic in nature.
Acoustic stressors include effects of heavy equipment operation during
pile driving activities.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving activities is the primary means by which
marine mammals may be harassed from CTJV's specified activities. In
general, animals exposed to natural or anthropogenic sound may
experience behavioral, physiological, and/or physical effects, ranging
in magnitude from none to severe (Southall et al., 2007). Generally,
exposure to pile driving activities has the potential to result in
behavioral reactions (e.g., avoidance, temporary cessation of foraging
and vocalizing, changes in dive behavior) and, in limited cases,
auditory threshold shifts. Exposure to anthropogenic noise can also
lead to non-observable physiological responses such as an increase in
stress hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions such
as communication and predator and prey detection. The effects of pile
driving activities on marine mammals are dependent on several factors,
including, but not limited to, sound type (e.g., impulsive vs. non-
impulsive), the species, age and sex class (e.g., adult male vs. mother
with calf), duration of exposure, the distance between the pile and the
animal, received levels, behavior at time of exposure, and previous
history with exposure (Wartzok et al., 2003; Southall et al., 2007).
Here we discuss physical auditory effects (threshold shifts) followed
by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (2018), there are numerous factors
to consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how animal uses sound within the
frequency band of the signal; e.g., Kastelein et al., 2014), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40-dB
threshold shift approximates PTS onset (Ward et al., 1958; Ward et al.,
1959; Ward, 1960; Kryter et al., 1966; Miller, 1974; Henderson et al.,
2008). PTS levels for marine mammals are estimates, because there are
limited empirical data measuring PTS in marine mammals (e.g., Kastak et
al., 2008), largely due to the fact that, for various ethical reasons,
experiments involving anthropogenic noise exposure at levels inducing
PTS are not typically pursued or authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--A temporary, reversible increase
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018). Based on data from cetacean TTS measurements
(Southall et al., 2007), a TTS of 6 dB is considered the minimum
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et
al., 2000; Finneran et al., 2000). As described in Finneran (2016),
marine mammal studies have shown the amount of TTS increases with
cumulative sound exposure level (SEL<INF>cum</INF>) in an accelerating
fashion: At low exposures with lower SEL<INF>cum</INF>, the amount of
TTS is typically small and the growth curves have shallow slopes. At
exposures with higher SEL<INF>cum</INF>, the growth curves become
steeper and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in Auditory
Masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost. Currently, TTS data only exist for four
species of cetaceans (bottlenose dolphin, beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis) and five species of pinnipeds exposed to a limited
number of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran, 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran, 2015). Additionally, the existing marine mammal TTS data
come from a limited number of individuals within these species. No data
are available on noise-induced hearing loss for mysticetes. For
summaries of data on TTS in marine mammals or for further discussion of
TTS onset thresholds, please see Southall et al. (2007), Finneran and
Jenkins (2012), Finneran (2015), and table 5 in NMFS (2018).
Activities for this project include impact and vibratory pile
driving. There would likely be pauses in activities producing the sound
during each day. Given these pauses and the fact that many marine
mammals are likely moving through the project areas and not remaining
for extended periods of time, the potential for threshold shift
declines.
Behavioral harassment--Exposure to noise from pile driving
activities has the potential to behaviorally disturb marine mammals.
Available studies show wide variation in response to underwater sound;
therefore, it is difficult to predict specifically how any given sound
in a particular instance might affect marine
[[Page 89393]]
mammals perceiving the signal. If a marine mammal does react briefly to
an underwater sound by changing its behavior or moving a small
distance, the impacts of the change are unlikely to be significant to
the individual, let alone the stock or population. However, if a sound
source displaces marine mammals from an important feeding or breeding
area for a prolonged period, impacts on individuals and populations
could be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007;
National Research Council (NRC), 2005).
The following subsections provide examples of behavioral responses
that provide an idea of the variability in behavioral responses that
would be expected given the differential sensitivities of marine mammal
species to sound and the wide range of potential acoustic sources to
which a marine mammal may be exposed. Behavioral responses that could
occur for a given sound exposure should be determined from the
literature that is available for each species, or extrapolated from
closely related species when no information exists, along with
contextual factors. Available studies show wide variation in response
to underwater sound; therefore, it is difficult to predict specifically
how any given sound in a particular instance might affect marine
mammals perceiving the signal. There are broad categories of potential
response, which we describe in greater detail here, that include
alteration of dive behavior, alteration of foraging behavior, effects
to respiration, interference with or alteration of vocalization,
avoidance, and flight.
Pinnipeds may increase their haul out time, possibly to avoid in-
water disturbance (Thorson and Reyff, 2006). Behavioral reactions can
vary not only among individuals but also within an individual,
depending on previous experience with a sound source, context, and
numerous other factors (Ellison et al., 2012), and can vary depending
on characteristics associated with the sound source (e.g., whether it
is moving or stationary, number of sources, distance from the source).
In general, pinnipeds seem more tolerant of, or at least habituate more
quickly to, potentially disturbing underwater sound than do cetaceans,
and generally seem to be less responsive to exposure to industrial
sound than most cetaceans.
Alteration of Feeding Behavior--Disruption of feeding behavior can
be difficult to correlate with anthropogenic sound exposure, so it is
usually inferred by observed displacement from known foraging areas,
the appearance of secondary indicators (e.g., bubble nets or sediment
plumes), or changes in dive behavior. As for other types of behavioral
response, the frequency, duration, and temporal pattern of signal
presentation, as well as differences in species sensitivity, are likely
contributing factors to differences in response in any given
circumstance (e.g., Croll et al., 2001; Nowacek et al., 2004; Madsen et
al., 2006; Yazvenko et al., 2007). In addition, behavioral state of the
animal plays a role in the type and severity of a behavioral response,
such as disruption to foraging (e.g., Silve et al., 2016; Wensveen et
al., 2017). An evaluation of whether foraging disruptions would be
likely to incur fitness consequences considers temporal and spatial
scale of the activity in the context of the available foraging habitat
and, in more severe cases may necessitate consideration of information
on or estimates of the energetic requirements of the affected
individuals and the relationship between prey availability, foraging
effort and success, and the life history stage of the animal. Goldbogen
et al. (2013) indicate that disruption of feeding and displacement
could impact individual fitness and health. However, for this to be
true, we would have to assume that an individual could not compensate
for this lost feeding opportunity by either immediately feeding at
another location, by feeding shortly after cessation of acoustic
exposure, or by feeding at a later time. There is no indication this is
the case here, particularly since prey would likely still be available
in the environment in most cases following the cessation of acoustic
exposure.
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness. Neuroendocrine stress responses often involve the
hypothalamus-pituitary-adrenal system. Virtually all neuroendocrine
functions that are affected by stress--including immune competence,
reproduction, metabolism, and behavior--are regulated by pituitary
hormones. Stress-induced changes in the secretion of pituitary hormones
have been implicated in failed reproduction, altered metabolism,
reduced immune competence, and behavioral disturbance (e.g., Moberg,
1987; Blecha, 2000). Increases in the circulation of glucocorticoids
are also equated with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003), however
distress is an unlikely result of these projects based on observations
of marine mammals during previous, similar projects.
Auditory Masking--Sound can disrupt behavior through masking, or
interfering with, an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance,
[[Page 89394]]
navigation) (Richardson et al., 1995). Masking occurs when the receipt
of a sound is interfered with by another coincident sound at similar
frequencies and at similar or higher intensity, and may occur whether
the sound is natural (e.g., snapping shrimp, wind, waves,
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar,
seismic exploration) in origin. The ability of a noise source to mask
biologically important sounds depends on the characteristics of both
the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions. Masking of natural sounds can result when human activities
produce high levels of background sound at frequencies important to
marine mammals. Conversely, if the background level of underwater sound
is high (e.g., on a day with strong wind and high waves), an
anthropogenic sound source would not be detectable as far away as would
be possible under quieter conditions and would itself be masked. The
mouth of the Chesapeake Bay contains active military and commercial
shipping, as well as numerous recreational and other commercial vessel
and background sound levels in the area are already elevated.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and removal that have the potential to cause behavioral harassment,
depending on their distance from pile driving activities. Cetaceans are
not expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA. Airborne noise would primarily be
an issue for pinnipeds that are swimming or hauled out near the project
site within the range of noise levels elevated above the acoustic
criteria. We recognize that pinnipeds in the water could be exposed to
airborne sound that may result in behavioral harassment when looking
with their heads above water. Most likely, airborne sound would cause
behavioral responses similar to those discussed above in relation to
underwater sound. For instance, anthropogenic sound could cause hauled
out pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to temporarily abandon the
area and move further from the source. However, these animals would
likely previously have been `taken' because of exposure to underwater
sound above the behavioral harassment thresholds, which are generally
larger than those associated with airborne sound. Thus, the behavioral
harassment of these animals is already accounted for in these estimates
of potential take. Therefore, we do not believe that authorization of
additional incidental take resulting from airborne sound for pinnipeds
is warranted, and airborne sound is not discussed further.
Marine Mammal Habitat Effects
CTJV's proposed construction activities could have localized,
temporary impacts on marine mammal habitat, including prey, by
increasing in-water sound pressure levels and slightly decreasing water
quality. Increased noise levels may affect acoustic habitat (see
Auditory Masking discussion above) and adversely affect marine mammal
prey in the vicinity of the project areas (see discussion below).
Elevated levels of underwater noise would ensonify the project areas
where both fishes and mammals occur and could affect foraging success.
Additionally, marine mammals may avoid the area during construction;
however, displacement due to noise is expected to be temporary and is
not expected to result in long-term effects to the individuals or
populations.
In-water Construction Effects on Potential Prey--Construction
activities would produce continuous (i.e., vibratory pile driving) and
intermittent (i.e., impact pile driving) sounds. Sound may affect
marine mammals through impacts on the abundance, behavior, or
distribution of prey species (e.g., crustaceans, cephalopods, fish,
zooplankton). Marine mammal prey varies by species, season, and
location. Here, we describe studies regarding the effects of noise on
known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay,
2009). Depending on their hearing anatomy and peripheral sensory
structures, which vary among species, fishes hear sounds using pressure
and particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent
low-frequency sounds, and behavioral responses such as flight or
avoidance are the most likely effects. Short duration, sharp sounds can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to noise depends on the physiological state of the
fish, past exposures, motivation (e.g., feeding, spawning, migration),
and other environmental factors. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pile
driving on fish; several are based on studies in support of large,
multiyear bridge construction projects (e.g., Scholik and Yan, 2001;
Scholik and Yan, 2002; Popper and Hastings, 2009). Several studies have
demonstrated that impulse sounds might affect the distribution and
behavior of some fishes, potentially impacting foraging opportunities
or increasing energetic costs (e.g., Fewtrell and McCauley, 2012;
Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999;
Paxton et al., 2017). However, some studies have shown no or slight
reaction to impulse sounds (e.g., Pena et al., 2013; Wardle et al.,
2001; Jorgenson and Gyselman, 2009).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4 to 6 dB was recoverable within 24
hours for one species. Impacts would be most severe when the individual
fish is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fishes from pile driving activities at
the project area would be temporary behavioral avoidance of the area.
The duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment,
[[Page 89395]]
distribution, and behavior is anticipated.
Construction activities have the potential to have adverse impacts
on forage fish in the project area in the form of increased turbidity.
Forage fish form a significant prey base for many marine mammal species
that occur in the project area. Turbidity within the water column has
the potential to reduce the level of oxygen in the water and irritate
the gills of prey fish in the proposed project area. However, fish in
the proposed project area would be able to move away from and avoid the
areas where increase turbidity may occur. Given the limited area
affected and ability of fish to move to other areas, any effects on
forage fish are expected to be minor or negligible.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed actions
are not likely to have a permanent, adverse effect on any fish habitat,
or populations of fish species. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity. Thus, we
conclude that impacts of the specified activities are not likely to
have more than short-term adverse effects on any prey habitat or
populations of prey species. Further, any impacts to marine mammal
habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to adverse
impacts on their populations.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic sources (i.e., impact and vibratory driving) has the
potential to result in disruption of behavioral patterns for individual
marine mammals. There is also some potential for auditory injury (Level
A harassment) to result, primarily for high frequency species and
phocids because predicted auditory injury zones are larger than for
mid-frequency species. Auditory injury is unlikely to occur for mid-
frequency species. The proposed mitigation and monitoring measures are
expected to minimize the severity of the taking to the extent
practicable.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur. CTJV's proposed
activities include the use of continuous (vibratory pile driving) and
impulsive (impact pile driving) sources, and therefore the RMS SPL
thresholds of 120 and 160 dB re 1 [mu]Pa are applicable.
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise from
two different types of sources (impulsive or non-impulsive). CTJV's
proposed pile driving activities includes the use of impulsive (impact
pile driving) and non-impulsive (vibratory pile driving) sources.
These thresholds are provided in table 4 below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
<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>.
[[Page 89396]]
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS Onset Acoustic Thresholds * (Received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., pile driving).
The project includes vibratory and impact pile driving. Source
levels for these activities are based on reviews of measurements of the
same or similar types and dimensions of piles available in the
literature. Source levels for each pile size and activity are presented
in table 5. Source levels for vibratory pile removal and installation
of piles of the same diameter are assumed to be the same. Note that
CTJV will employ a bubble curtain during all impact and vibratory
driving activities which NMFS assumes will reduce source levels by 5
dB.
Table 5--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
Pile type Hammer type Peak RMS SSsel Source
----------------------------------------------------------------------------------------------------------------
36-in steel pipe............. Impact/(with 5 210/(205) 193/(188) 183/(178) Caltrans 2015,
dB bubble 2020.
curtain).
Vibratory/(with - 180/(175) 170/(165) .............. Caltrans 2015.
5 dB bubble
curtain).
----------------------------------------------------------------------------------------------------------------
Note: CTJV will incorporate bubble curtain with a 5 dB reduction for all pile driving activities.
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B * Log10 (R1/R2),
where
TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement
Absent site-specific acoustical monitoring with differing measured
transmission loss, a practical spreading value of 15 is used as the
transmission loss coefficient in the above formula. Site-specific
transmission loss data for the PTST project area are not available;
therefore, the default coefficient of 15 is used to determine the
distances to the Level A harassment and Level B harassment thresholds.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the Technical Guidance that can be used
to relatively simply predict an isopleth distance for use in
conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources, such as pile driving, the optional User Spreadsheet
tool predicts the distance at which, if a marine mammal remained at
that distance for the duration of the activity, it would be expected to
incur PTS. Inputs used in the optional User Spreadsheet tool are shown
in table 6, and the resulting estimated isopleths are shown in table 7,
as reported below.
[[Page 89397]]
Table 6--User Spreadsheet Inputs
------------------------------------------------------------------------
36-inch steel piles
-------------------------------
Vibratory Impact
------------------------------------------------------------------------
Source Level (SPL)...................... 170 RMS 183 SEL
Transmission Loss Coefficient........... 15 15
Weighting Factor Adjustment (kHz)....... 2.5 2
Activity Duration per day (minutes)..... 30 ..............
Number of strikes per pile.............. .............. 240
Number of piles per day................. 2 2
Distance of sound pressure level 10 10
measurement............................
------------------------------------------------------------------------
Table 7--Calculated Level A and Level B Harassment Isopleths
[Meters]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment zones
Scenario ---------------------------------------------------------------------------------------------- Level B harassment
LF MF HF Phocid pinnipeds zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
Driving Type:
Pile Type...................... Island 1 & 2.......... Island 1 & 2.......... Island 1 & 2......... Island 1 & 2......... Island 1 & 2.
36-in Impact (with Bubble Curtain):
36-in. Steel................... 285................... 10.................... 338.................. 152.................. 736.
36-inVibratory (with Bubble
Curtain):
36-in. Steel................... 8..................... 1..................... 12................... 5.................... 10,000.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence and Take Estimation
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations as well as how the information
provided is synthesized to produce a quantitative estimate of the take
that is reasonably likely to occur and proposed for authorization.
Several approaches were utilized to estimate take for affected species
depending on the best data that was available. For some species, survey
or observational data was used to estimate take (e.g., harbor seal,
gray seal). If density data was available, it was employed to develop
the take estimate (i.e., bottlenose dolphin). In cases where the best
available information consisted only of very low density values, NMFS
assumed the average group to arrive at an estimate (i.e., humpback
whale, harbor porpoise).
Humpback Whale
Humpback whales are rare in the Chesapeake Bay. Density data for
this species within the project vicinity were not available. Habitat-
based density models produced by the Duke University Marine Geospatial
Ecology Laboratory (Roberts et al. 2016) represent the best available
information regarding marine mammal densities offshore near the mouth
of the Chesapeake Bay. At the closest point to the PTST project area,
humpback densities showed a maximum monthly density of 0.107/100 km\2\
in March. Because humpback whale occurrence is low, as mentioned above,
the CTJV estimated, and NMFS concurred, that there will be a single
humpback sighting every two months for the duration of in-water pile
driving activities. There are 5 months of planned in-water
construction. Using an average group size of two animals Kraus et al.
(2016) and 5 months of active in-water pile driving work (Jan, Feb,
Mar, Apr, Dec) provides an estimate of four takes during the January-
April period. NMFS conservatively assumed that there would be an
additional sighting of 2 humpback whales in December. Because it is
expected that a full shutdown can occur before the mammal can reach the
full extent of the Level A harassment zone, no takes by Level A
harassment were requested or are expected. Therefore, NMFS proposes to
authorize six takes of humpback whale by Level B harassment.
Bottlenose Dolphin
There was insufficient monitoring data available from previous PTST
IHAs to estimate dolphin take. Therefore, the expected number of
bottlenose dolphins was estimated using a 2016 report on the
occurrence, distribution, and density of marine mammals near Naval
Station Norfolk and Virginia Beach, Virginia (Engelhaupt et al. 2016).
This report provides seasonal densities of bottlenose dolphins for
inshore areas in the vicinity of the project and along the coast of
Virginia Beach. Like most wildlife, bottlenose dolphins do not use
habitat uniformly. The heterogeneity in available habitat, dietary
items and protection likely results in some individuals preferring
ocean and others estuary (Ballance 1992; Gannon and Waples 2004).
Dolphins clearly have the ability to move between these habitat types.
Gannon and Waples (2004) suggest individuals prefer one habitat over
the other based on gut contents of dietary items. Therefore, a subset
of survey data from Engelhaupt et al. (2016) was used to determine
seasonal dolphin densities within the project area. A spatially refined
approach was used by plotting dolphin sightings within a 12 km radius
of the proposed project location. Densities were determined following
methodology outlined in Engelhaupt et al. 2016 and Miller et al. 2019
using the package DISTANCE in R statistical software (R. Core Team
2018). Calculated densities by season are provided in table 8.
Table 8--Densities (Individual/km\2\) of Bottlenose Dolphin From Inshore
Areas of Virginia
------------------------------------------------------------------------
12 km distance
Season around PTST
project area
------------------------------------------------------------------------
Spring.................................................. 1.00
Winter.................................................. 0.63
------------------------------------------------------------------------
This information was then used to calculate the monthly takes based
on the number of pile driving days per month. These were broken out by
month as
[[Page 89398]]
shown in table 9. The Level B harassment area for each pile and driving
type was multiplied by the appropriate seasonal density and the
anticipated number of days per activity per month to derive the total
number of takes for each activity. Given this information, NMFS is
proposing to authorize a total of 12,256 Level B harassment exposures
for bottlenose dolphins. No take by Level A harassment is proposed by
NMFS since the shutdown zone is 30 m and should be readily visible to
PSOs.
Table 9--Estimated Takes of Bottlenose Dolphin by Level B Harassment by Month, Location, and Driving Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Month Jan Feb Mar Apr Dec Totals
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dolphin Density (/km\2\)................................ 0.63 0.63 1 1 0.63 ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact: Portal Island 1 Mooring Dolphins (9 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)................................... 1.38 1.38 1.38 1.38 1.38 ..............
Driving Days............................................ 2 3 0 0 0 ..............
Dolphin Harassments..................................... 2 3 0 0 0 5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory: Portal Island 1 Mooring Dolphins (9 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)................................... 212 212 212 212 212 ..............
Driving Days............................................ 2 3 0 0 0 ..............
Dolphin Harassments..................................... 268 401 0 0 0 669
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact: Portal Island 2 Mooring Dolphins (18 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)................................... 1.32 1.32 1.32 1.32 1.32 ..............
Driving Days............................................ 0 0 0 0 9 ..............
Dolphin Harassments..................................... 0 0 0 0 8 8
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory: Portal Island 2 Mooring Dolphins (18 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)................................... 202 202 202 202 202 ..............
Driving Days............................................ 0 0 0 0 9 ..............
Dolphin Harassments..................................... 0 0 0 0 1146 1146
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact: Portal Island 1 Trestle/Dock Removal (97 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)................................... 1.38 1.38 1.38 1.38 1.38 ..............
Driving Days............................................ 13 15 13 8 0 ..............
Dolphin Harassments..................................... 12 14 18 12 0 56
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory: Portal Island 1 Trestle/Dock Removal (97 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)................................... 212 212 212 212 212 ..............
Driving Days............................................ 13 15 13 8 0 ..............
Dolphin Harassments..................................... 1737 2004 2756 1696 0 8193
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact: Portal Island 2 Trestle Removal (34 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)................................... 1.32 1.32 1.32 1.32 1.32 ..............
Driving Days............................................ 0 0 0 0 17 ..............
Dolphin Harassments..................................... 0 0 0 0 15 15
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory: Portal Island 2 Trestle Removal (34 Piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refined Area (/km\2\)................................... 202 202 202 202 202 ..............
Driving Days............................................ 0 0 0 0 17 ..............
Dolphin Harassments..................................... 0 0 0 0 2164 2164
-----------------------------------------------------------------------------------------------
Total............................................... .............. .............. .............. .............. .............. 12,256
--------------------------------------------------------------------------------------------------------------------------------------------------------
The total number of bottlenose dolphin Level B harassment events
will be split between three bottlenose dolphin stocks: Western North
Atlantic Southern Migratory Coastal; Western North Atlantic Northern
Migratory Coastal; and NNCES. There is insufficient information to
apportion the requested takes precisely to each of these three stocks
present in the project area. Given that most of the NNCES stock are
found in the Pamlico Sound estuarine system, it is assumed that no
greater than 200 of the takes will be from this stock. Since members of
the Western North Atlantic Northern Migratory Coastal and Western North
Atlantic Southern Migratory Coastal stocks are thought to occur in or
near the project area in greater numbers, we conservatively assume that
no more than half of the remaining animals will belong to either of
these stocks. Additionally, a subset of these takes would likely be
comprised of Chesapeake Bay resident dolphins, although the size of
that population is unknown. It is assumed that an animal will be taken
once over a 24-hour period; however, the same individual
[[Page 89399]]
may be taken multiple times over the duration of the project.
Therefore, the number of takes for each stock is assumed to
overestimate the actual number of individuals that may be affected.
Harbor Porpoise
Harbor porpoises are known to occur in the coastal waters near
Virginia Beach (Hayes et al. 2019), and although they have been
reported on rare occasions in the Chesapeake Bay near the project area,
they have not been seen by the Protected Species Observers in the PTST
project area during the construction. Density data for this species
within the project vicinity do not exist or were not calculated because
sample sizes were too small to produce reliable estimates of density.
Additionally, harbor porpoise sighting data collected by the U.S. Navy
near Naval Station Norfolk and Virginia Beach from 2012 to 2015
(Engelhaupt et al. 2014, 2015, 2016) did not produce high enough sample
sizes to calculate densities.
One group of two harbor porpoises was seen during spring 2015
(Engelhaupt et al. 2016). Therefore, it is assumed that there are two
harbor porpoises exposed to noise exceeding harassment levels each
month during the spring (March-April) for a total of four harbor
porpoises (i.e., 1 group of 2 individuals per month x 2 months per year
= 4 harbor porpoises). Harbor porpoises are not expected to be present
in the summer, fall or winter. Harbor porpoises are members of the
high-frequency hearing group which would have Level A harassment
isopleths as large as 338 m during impact driving of 36'' steel pile,
while the Level B harassment zone is 736 m. Given the relatively large
Level A harassment zones for HF cetaceans during impact driving and a
required shutdown zone of 200 m, NMFS will assume that 30 percent of
porpoises are taken by Level A harassment. Therefore, NMFS proposes to
authorize take of three porpoises by Level B harassment and one
porpoise by Level A harassment.
Harbor Seal
The expected number of harbor seals in the project area was
estimated using systematic, land and vessel-based survey data for in-
water and hauled-out seals collected by the U.S. Navy at the CBBT rock
armor and Portal Islands from November 2014 through April 2022 (Rees et
al. 2016; Jones et al. 2018; Jones and Rees 2020; Jones and Rees 2021;
Jones and Rees 2022; Jones and Rees 2023) and shown in table 10. The
number of harbor seals sighted by month ranged from 0 to 170
individuals.
Table 10--Summary of Historical Harbor Seal Sightings by Month From 2014 to 2022 at the Chesapeake Bay Bridge Tunnel
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Monthly
Month 2014 2015 2016 2017 2018 2019 2020 2021 2022 average
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
January....................................................... ........... ........... 33 120 170 7 18 49 34 61.6
February...................................................... ........... 39 80 106 159 21 0 43 14 57.7
March......................................................... ........... 55 61 41 0 18 6 26 37 30.5
April......................................................... ........... 10 1 3 3 4 0 6 1 3.5
December...................................................... 4 9 24 8 29 0 4 11 11 12.5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Seal counts began in November 2014 and were collected for 9 field seasons (2014/2015, 2015/2016, 2016/2017, 2017/2018, 2018/2019, 2019/2020, 2020/2021, 2021/2022) ending in 2022. In
January 2015, no surveys were conducted.
Seal density data are in the format of seal per unit time;
therefore, seal take requests were calculated as total number of
potential seals per pile driving day (8 hours) multiplied by the number
of driving days per month. For example, in December seal density data
is reported at 14.3 seals per day * 26 workdays in December, resulting
in the potential of 372 instances of take for that month (table 11).
The anticipated number of take events were summed across the months
during which in-water pile driving is planned. The largest Level A
harassment isopleth for phocid species is 153 m which would occur when
piles were being removed via impact hammer with a bubble curtain. The
smallest Level A harassment zone is 1 m which would occur when piles
are removed via vibratory hammer with a bubble curtain. NMFS is
proposing to require a shutdown zone for harbor seals of 160 m during
impact driving which would theoretically result in no take by Level A
harassment. However, a small number of harbor seals could enter into
the shutdown zone unseen by a PSO and remain for sufficient duration to
incur PTS. Given that harbor seals are common in the project area, NMFS
assumed that a single harbor seal would experience Level A harassment
during each in-water work day (80). Therefore, NMFS proposes to
authorize the take of 80 harbor seals by Level A harassment and 2,634
harbor seals by Level B harassment for a total of 2,714 takes (table
11).
Table 11--Calculation of the Number of Harbor Seal Takes
----------------------------------------------------------------------------------------------------------------
Estimated Total pile Total number
Month seals per work driving days of requested
day per month takes
----------------------------------------------------------------------------------------------------------------
January 2024.................................................... 61.6 15 924
February 2024................................................... 57.8 18 1,040
March 2024...................................................... 30.5 13 396.5
April 2024...................................................... 3.5 8 28
December 2024................................................... 12.5 26 325
2,714
----------------------------------------------------------------------------------------------------------------
Gray Seal
The number of gray seals expected to be present at the PTST project
area was estimated using the same methodology as was used for the
harbor seal. Survey data collected by the U.S. Navy at the portal
islands from 2015 through 2022 was utilized (Rees et al. 2016; Jones et
al. 2018; Jones and Rees 2023). A maximum of 1 gray seal was seen
during the months of February 2015, 2016, and
[[Page 89400]]
2022. Given this information NMFS assumed that a single gray seal would
be taken per work day in February 2024.The anticipated numbers of
monthly takes were calculated following the same approach as for harbor
seals, and the monthly takes were then summed (table 12). Although the
project has not recorded any gray seal sightings to date, NMFS assumed
that, over the duration of the project, a single gray seal could enter
into the Level A harassment zone unseen by a PSO and remain for
sufficient duration to incur PTS. Therefore, NMFS is proposing to
authorize the take of 1 gray seal by Level A harassment and 17 gray
seals by Level B harassment for a total of 18 proposed takes.
Table 12--Calculation of the Number of Gray Seal Takes
----------------------------------------------------------------------------------------------------------------
Estimated Total pile Total number
Month seals per work driving days of requested
day per month takes
----------------------------------------------------------------------------------------------------------------
January 2024.................................................... 0 15 0
February 2024................................................... 1 18 18
March 2024...................................................... 0 13 0
April 2024...................................................... 0 8 0
December 2024................................................... 0 26 0
-----------------------------------------------
Total....................................................... .............. .............. 18
----------------------------------------------------------------------------------------------------------------
Table 13 shows the take numbers proposed for authorization by NMFS
as well as the percentage of each stock affected.
Table 13--Proposed Take by Stock and Harassment Type as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Level A Level B Percent of
Species Stock harassment harassment Total stock
----------------------------------------------------------------------------------------------------------------
Humpback Whale................ Gulf of Maine... 0 6 6 0.4
Harbor Porpoise............... Gulf of Maine/ 1 3 4 <0.01
Bay of Fundy.
Bottlenose Dolphin............ WNA Coastal, 0 6,028 6,028 90.8
Northern
Migratory.
WNA Coastal, 0 6,028 6,028 160.1
Southern
Migratory.
NNCES........... 0 200 200 24.3
Harbor Seal................... Western North 80 2,634 2,714 4.4
Atlantic.
Gray Seal..................... Western North 1 17 18 <0.01
Atlantic.
----------------------------------------------------------------------------------------------------------------
The monitoring results from work conducted in 2020 and 2021 are
found in table 14. The results demonstrate significantly fewer takes by
harassment than were authorized, and it is important to note that
estimates in the previous IHAs as well as in this proposed IHA are
based on conservative assumptions, including the size of identified
harassment zones and the abundance of marine mammals. However, we note
that these assumptions represent the best available information in this
case.
Table 14--Marine Mammal Monitoring Results From IHAs Issued in 2020 and 2021
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Observations Observations Observations Observations
Level A Level B in level A in level B Level A Level B in level A in level B
Species Stock harassments harassments harassment harassment harassments harassments harassment harassment
authorized authorized zones under zones under authorized authorized zones under zones under
in 2020 IHA in 2020 IHA 2020 IHA 2020 IHA in 2021 IHA in 2021 IHA 2021 IHA 2021 IHA
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback Whale................................ Gulf of Maine................... ............ 12 ............ ............ ............ 12 ............ ............
Harbor Porpoise............................... Gulf of Maine/Bay of Fundy...... 5 7 ............ ............ 5 7 ............ ............
Bottlenose Dolphin............................ WNA Coastal, Northern Migratory. 142 14,095 ............ 5 ............ 43,203 ............ 394
WNA Coastal, Southern Migratory. 142 14,095 ............ ............ ............ 43,203 ............ ............
NNCES........................... 2 198 ............ ............ ............ 250 ............ ............
Harbor Seal................................... Western North Atlantic.......... 1,296 2,124 ............ ............ 1154 1,730 ............ ............
Gray Seal..................................... Western North Atlantic.......... 1 3 ............ ............ 16 24 ............ ............
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds,
[[Page 89401]]
and areas of similar significance, and on the availability of the
species or stock for taking for certain subsistence uses (latter not
applicable for this action). NMFS regulations require applicants for
incidental take authorizations to include information about the
availability and feasibility (economic and technological) of equipment,
methods, and manner of conducting the activity or other means of
effecting the least practicable adverse impact upon the affected
species or stocks, and their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost and impact on
operations.
CTJV must conduct training between construction supervisors, crews,
marine mammal monitoring team, and relevant CTJV staff prior to the
start of all pile driving activities and when new personnel join the
work, so that responsibilities, communication procedures, monitoring
protocols, and operational procedures are clearly understood.
Construction supervisors and crews, PSOs, and relevant CTJV staff
must avoid direct physical interaction with marine mammals during
construction activity. If a marine mammal comes within 10 m of such
activity, operations must cease and vessels must reduce speed to the
minimum level required to maintain steerage and safe working
conditions, as necessary to avoid direct physical interaction. If an
activity is delayed or halted due to the presence of a marine mammal,
the activity may not commence or resume until either the animal has
voluntarily exited and been visually confirmed beyond the shutdown zone
indicated in table 15 or 15 minutes have passed without re-detection of
the animal.
Construction activities must be halted upon observation of a
species for which incidental take is not authorized or a species for
which incidental take has been authorized but the authorized number of
takes has been met entering or within the harassment zone.
Shutdown Zones--For all pile driving activities, CTJV would
implement shutdowns within designated zones. The purpose of a shutdown
zone is generally to define an area within which shutdown of the
activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). Shutdown zones
vary based on the activity type and marine mammal hearing group (table
7). In most cases, the shutdown zones are based on the estimated Level
A harassment isopleth distances for each hearing group. However, in
cases where it would be challenging to detect marine mammals at the
Level A harassment isopleth, (e.g., for high frequency cetaceans and
phocids during impact driving activities), smaller shutdown zones have
been proposed (table 15).
Table 15--Shutdown and Monitoring Zones
[Meters]
----------------------------------------------------------------------------------------------------------------
Monitoring
Method and piles LF cetaceans MFcetaceans HF cetaceans Phocids zone
----------------------------------------------------------------------------------------------------------------
36-in Impact (with bubble 285 20 200 160 736
Curtain).......................
36-in Vibratory (with bubble 10 10 15 10 10,000
curtain).......................
----------------------------------------------------------------------------------------------------------------
Protected Species Observers--The number and placement of PSOs
during all construction activities (described in the Proposed
Monitoring and Reporting section as well as the Marine Mammal
Monitoring Plan) would ensure that the entire shutdown zone is visible.
A minimum of one PSO must be employed for all driving activities and
placed at a location providing, at a minimum, adequate views of the
established shutdown zones.
Monitoring for Level B Harassment--PSOs would monitor the shutdown
zones and beyond to the extent that PSOs can see. Monitoring beyond the
shutdown zones enables observers to be aware of and communicate the
presence of marine mammals in the project areas outside the shutdown
zones and thus prepare for a potential cessation of activity should the
animal enter the shutdown zone. If a marine mammal enters the Level B
harassment zone (or Level A harassment zone if larger than the Level B
harassment zone), PSOs will document the marine mammal's presence and
behavior.
Pre and Post-Activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving of 30
minutes or longer occurs, PSOs will observe the shutdown, Level A
harassment, and Level B harassment zones for a period of 30 minutes.
Pre-start clearance monitoring must be conducted during periods of
visibility sufficient for the lead PSO to determine that the shutdown
zones are clear of marine mammals. If the shutdown zone is obscured by
fog or poor lighting conditions, in-water construction activity will
not be initiated until the entire shutdown zone is visible. Pile
driving activities may commence following 30 minutes of observation
when the determination is made that the shutdown zones are clear of
marine mammals. If a marine mammal is observed entering or within
shutdown zones, pile driving activities must be delayed or halted. If
pile driving is delayed or halted due to the presence of a marine
mammal, the activity may not commence or resume until either the animal
has voluntarily exited and been visually confirmed beyond the shutdown
zone or 15 minutes have passed for all other species without re-
detection of the animal.
Soft Start--The use of soft-start procedures are believed to
provide additional protection to marine mammals by providing warning
and/or giving marine mammals a chance to leave the area prior to the
hammer operating at full capacity. For impact pile driving, contractors
would be required to provide an initial set of three strikes from the
hammer at reduced energy, with each strike followed by a 30-second
waiting period. This procedure would be conducted a total of three
times before impact pile driving
[[Page 89402]]
begins. Soft start would be implemented at the start of each day's
impact pile driving activities and at any time following cessation of
impact pile driving activities for a period of 30 minutes or longer.
Soft start is not required during vibratory pile driving activities.
Bubble Curtain--Use of a bubble curtain during impact and vibratory
pile driving in water depths greater than 3 m (10 ft) would be
required. It must be operated as necessary to achieve optimal
performance, and there can be no reduction in performance attributable
to faulty deployment. At a minimum, CTJV must adhere to the following
performance standards: The bubble curtain must distribute air bubbles
around 100 percent of the piling circumference for the full depth of
the water column. The lowest bubble ring must be in contact with the
substrate for the full circumference of the ring, and the weights
attached to the bottom ring shall ensure 100 percent substrate contact.
No parts of the ring or other objects shall prevent full substrate
contact. Air flow to the bubblers must be balanced around the
circumference of the pile.
Based on our evaluation of the applicant's proposed measures NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<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
would constrain the ensonified area to only one side (i.e., east or
west) of the bridge tunnel structure. Additionally, CTJV expressed
concern that since they will only be using one drill for about two
hours per week, it will be difficult to secure multiple observers
willing to commit to the PTST project.
Monitoring will be conducted 30 minutes before, during, and 30
minutes after all in water construction activities. In addition, PSOs
will record all incidents of marine mammal occurrence, regardless of
distance from activity, and will document any behavioral reactions in
concert with distance from piles being removed. Pile driving activities
include the time to remove a single pile or series of piles, as long as
the time elapsed between uses of the pile driving equipment is no more
than 30 minutes.
Reporting
CTJV will submit a draft marine mammal monitoring report to NMFS
within 90 days after the completion of pile driving activities, or 60
days prior to a requested date of issuance of any future IHAs for the
project, or other projects at the same location, whichever comes first.
The marine mammal monitoring report will include an overall description
of work completed, a narrative regarding marine mammal sightings, and
associated PSO data sheets. Specifically, the report will include:
<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,
[[Page 89403]]
vibratory); and (2) Total duration of driving time for each pile
(vibratory) and number of strikes for each pile (impact);
<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 would constitute the final report. If comments are
received, a final report addressing NMFS comments must be submitted
within 30 days after receipt of comments. The Holder must submit all
PSO data electronically in a format that can be queried such as a
spreadsheet or database (i.e., digital images of data sheets are not
sufficient).
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the Holder must report the
incident to the Office of Protected Resources (OPR), NMFS
(<a href="/cdn-cgi/l/email-protection#4e1e1c60071a1e60032120273a213c2720291c2b3e213c3a3d0e20212f2f60292138"><span class="__cf_email__" data-cfemail="f4a4a6dabda0a4dab99b9a9d809b869d9a93a691849b868087b49a9b9595da939b82">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#0d44595d237d6c78616463684d63626c6c236a627b"><span class="__cf_email__" data-cfemail="470e1317693726322b2e2922072928262669202831">[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 Proposed
Mitigation section).
We anticipate that harbor porpoises, harbor seals and gray seals
may sustain some limited Level A harassment in the form of auditory
injury. However, animals in these locations that experience PTS would
likely only receive slight PTS, i.e., minor degradation of hearing
capabilities within regions of hearing that align most completely with
the energy produced by pile driving, i.e., the low-frequency region
below 2 kHz, not severe hearing impairment or impairment in the regions
of greatest hearing sensitivity. If hearing impairment occurs, it is
most likely that the affected animal would lose a few decibels in its
hearing sensitivity, which in most cases is not likely to meaningfully
affect its ability to forage and communicate with conspecifics. Impacts
to individual fitness, reproduction, or survival are unlikely. As
described above, we expect that marine mammals would be likely to move
away from a sound source that represents an aversive stimulus,
especially at levels that would be expected to result in PTS, given
[[Page 89404]]
sufficient notice through use of soft start.
Behavioral responses of marine mammals to pile driving at the
project site, if any, are expected to be mild and temporary. Marine
mammals within the Level B harassment zone may not show any visual cues
they are disturbed by activities or could become alert, avoid the area,
leave the area, or display other mild responses that are not observable
such as changes in vocalization patterns. Given the short duration of
noise-generating activities per day, any harassment would be temporary.
There are no other areas or times of known biological importance for
any of the affected species.
We acknowledge the existence and concern about the ongoing humpback
whale UME. We have no evidence that this project is likely to result in
vessel strikes (a major correlate of the UME) and marine construction
projects in general involve the use of slow-moving vessels, such as
tugs towing or pushing barges, or smaller work boats maneuvering in the
vicinity of the construction project. These vessel types are not
typically associated with vessel strikes resulting in injury or
mortality. More generally, the UME does not yet provide cause for
concern regarding population-level impacts for humpback whales. Despite
the UME, the West Indies breeding population or DPS, remains healthy.
For all species and stocks, take would occur within a limited,
confined area (adjacent to the CBBT) of the stock's range and the
amount of take proposed to be authorized is extremely small when
compared to stock abundance. In addition, it is unlikely that minor
noise effects in a small, localized area of habitat would have any
effect on the stocks' ability to recover. In combination, we believe
that these factors, as well as the available body of evidence from
other similar activities, demonstrate that the potential effects of the
specified activities will have only minor, short-term effects on
individuals. The specified activities are not expected to impact rates
of recruitment or survival and will therefore not result in population-
level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> Authorized Level A harassment would 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 would 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 proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is less than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
The amount of take NMFS proposes to authorize is below one third of
the estimated stock abundance for humpback whale, harbor porpoise, gray
seal, and harbor seal (in fact, take is no more than 6 percent of the
abundance of the affected stocks, see table 13). This is likely a
conservative estimate because they assume all takes are of different
individual animals which is likely not the case. Some individuals may
return multiple times in a day, but PSOs would count them as separate
takes if they cannot be individually identified.
There are three bottlenose dolphin stocks that could occur in the
project area. Therefore, the estimated 12,256 dolphin takes by Level B
harassment would likely be split among the western North Atlantic
northern migratory coastal stock, western North Atlantic southern
migratory coastal stock, and NNCES stock. Based on the stocks'
respective occurrence in the area, NMFS estimated that there would be
no more than 200 takes from the NNCES stock, representing 24.3 percent
of that population, with the remaining takes split evenly between the
northern and southern migratory coastal stocks. Based on consideration
of various factors described below, we have determined the numbers of
individuals taken would comprise less than one-third of the best
available population abundance estimate of either coastal migratory
stock. Detailed descriptions of the stocks' ranges have been provided
in Description of Marine Mammals in the Area of Specified Activities.
Both the northern migratory coastal and southern migratory coastal
stocks have expansive ranges and they are the only dolphin stocks
thought to make broad-scale, seasonal migrations in coastal waters of
the western North Atlantic. Given the large ranges associated with
these two stocks it is unlikely that large segments of either stock
would approach the project area and enter into the Chesapeake Bay. The
majority of both stocks are likely to be found widely dispersed across
their respective habitat ranges and unlikely to be concentrated in or
near the Chesapeake Bay.
Furthermore, the Chesapeake Bay and nearby offshore waters
represent the boundaries of the ranges of each of the two coastal
stocks during migration. The northern migratory coastal stock is found
during warm water months from coastal Virginia, including the
Chesapeake Bay and Long Island, New York. The stock migrates south in
late summer and fall. During cold water months dolphins may be found in
coastal waters from Cape Lookout, North Carolina, to the North
Carolina/Virginia. During January-March, the southern migratory coastal
stock appears to move as far south as northern Florida. From April to
June, the stock moves back north to North Carolina. During the warm
water months of July-August, the stock is presumed to occupy coastal
waters north of Cape Lookout, North Carolina, to Assateague, Virginia,
including the Chesapeake Bay. There is likely some overlap between the
northern and southern migratory stocks during spring and fall
migrations, but the extent of overlap is unknown.
The Bay and waters offshore of the mouth are located on the
periphery of the migratory ranges of both coastal stocks (although
during different seasons). Additionally, each of the migratory coastal
stocks are likely to be
[[Page 89405]]
located in the vicinity of the Bay for relatively short timeframes.
Given the limited number of animals from each migratory coastal stock
likely to be found at the seasonal migratory boundaries of their
respective ranges, in combination with the short time periods (~2
months) animals might remain at these boundaries, it is reasonable to
assume that takes are likely to occur only within some small portion of
either of the migratory coastal stocks.
Both migratory coastal stocks likely overlap with the NNCES stock
at various times during their seasonal migrations. The NNCES stock is
defined as animals that primarily occupy waters of the Pamlico Sound
estuarine system (which also includes Core, Roanoke, and Albemarle
sounds, and the Neuse River) during warm water months (July-August).
Members of this stock also use coastal waters (<=1 km from shore) of
North Carolina from Beaufort north to Virginia Beach, Virginia,
including the lower Chesapeake Bay. Comparison of dolphin photo-
identification data confirmed that limited numbers of individual
dolphins observed in Roanoke Sound have also been sighted in the
Chesapeake Bay (Young, 2018). Like the migratory coastal dolphin
stocks, the NNCES stock covers a large range. The spatial extent of
most small and resident bottlenose dolphin populations is on the order
of 500 km\2\, while the NNCES stock occupies over 8,000 km\2\
(LeBrecque et al., 2015). Given this large range, it is again unlikely
that a preponderance of animals from the NNCES stock would depart the
North Carolina estuarine system and travel to the northern extent of
the stock's range and enter into the Bay. However, recent evidence
suggests that there is likely a small resident community of NNCES
dolphins of indeterminate size that inhabits the Chesapeake Bay year-
round (Eric Patterson, Personal Communication).
Many of the dolphin observations in the Bay are likely repeated
sightings of the same individuals. The Potomac-Chesapeake Dolphin
Project has observed over 1,200 unique animals since observations began
in 2015. Re-sightings of the same individual can be highly variable.
Some dolphins are observed once per year, while others are highly
regular with greater than 10 sightings per year (Mann, Personal
Communication). Similarly, using available photo-identification data,
Engelhaupt et al. (2016) determined that specific individuals were
often observed in close proximity to their original sighting locations
and were observed multiple times in the same season or same year.
Ninety-one percent of re-sighted individuals (100 of 110) in the study
area were recorded less than 30 km from the initial sighting location.
Multiple sightings of the same individual would considerably reduce the
number of individual animals that are taken by harassment. Furthermore,
the existence of a resident dolphin population in the Bay would
increase the percentage of dolphin takes that are actually re-sightings
of the same individuals.
In summary and as described above, the following factors primarily
support our preliminary determination regarding the incidental take of
small numbers of a species or stock:
<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 would be unlikely to find a high percentage of
any one stock concentrated in a relatively small area such as the
project area or the Bay;
<bullet> The Bay represents the migratory boundary for each of the
specified dolphin stocks and it would be unlikely to find a high
percentage of any stock concentrated at such boundaries;
<bullet> Many of the takes would be repeats of the same animal and
it is likely that a number of individual animals could be taken 10 or
more times.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA; 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species.
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to CTJV for conducting construction activities as part of
the PTST project near Virginia Beach, VA from January through December
2024 provided the previously mentioned mitigation, monitoring, and
reporting requirements are incorporated. A draft of the proposed IHA
can be found at: <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>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed
construction activities associated with the PTST project. We also
request comment on the potential renewal of this proposed IHA as
described in the paragraph below. Please include with your comments any
supporting data or literature citations to help inform decisions on the
request for this IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
<bullet> The request for renewal must include the following:
[[Page 89406]]
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: December 21, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2023-28514 Filed 12-26-23; 8:45 am]
BILLING CODE 3510-22-P
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</html>Indexed from Federal Register on December 27, 2023.
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