[Federal Register Volume 84, Number 227 (Monday, November 25, 2019)]
[Notices]
[Pages 64847-64872]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-25471]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XR035
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel
Project in Virginia Beach, Virginia
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the Chesapeake Tunnel Joint
Venture (CTJV) for authorization to take marine mammals incidental to
Parallel Thimble Shoal Tunnel Project (PTST) in Virginia Beach,
Virginia. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to issue an incidental harassment
authorization (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-year renewal that could be issued under certain circumstances and
if all requirements are met, as described in Request for Public
Comments at the end of this notice. NMFS will consider public comments
prior to making any final decision on the issuance of the requested
MMPA authorizations and agency responses will be summarized in the
final notice of our decision.
DATES: Comments and information must be received no later than December
26, 2019.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Physical comments should be sent to
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments
should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for
[[Page 64848]]
taking for subsistence uses (where relevant). Further, NMFS must
prescribe the permissible methods of taking and other means of
effecting the least practicable [adverse] impact on the affected
species or stocks and their habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stocks for taking for certain
subsistence uses (referred to in shorthand as ``mitigation''); and
requirements pertaining to the mitigation, monitoring and reporting of
such takings are set forth.
The definitions of all applicable MMPA statutory terms cited above
are included in the relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (incidental harassment authorizations with
no anticipated serious injury or mortality) of the Companion Manual for
NOAA Administrative Order 216-6A, which do not individually or
cumulatively have the potential for significant impacts on the quality
of the human environment and for which we have not identified any
extraordinary circumstances that would preclude this categorical
exclusion. Accordingly, NMFS has preliminarily determined that the
issuance of the proposed IHA qualifies to be categorically excluded
from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On May 24, 2019, NMFS received a request from the CTJV for an IHA
to take marine mammals incidental to pile driving and removal at the
Chesapeake Bay Bridge and Tunnel (CBBT) near Virginia Beach, Virginia.
The application was deemed adequate and complete on October 11, 2019.
The CTJV's request is for take of small numbers of harbor seal (Phoca
vitulina), gray seal (Halichoerus grypus), bottlenose dolphin (Tursiops
truncatus), harbor porpoise (Phocoena phocoena) and humpback whale
(Megaptera novaeangliae) by Level A and Level B harassment. Neither
CTJV nor NMFS expects serious injury or mortality to result from this
activity and, therefore, an IHA is appropriate.
NMFS previously issued an IHA to the CTJV for similar work (83 FR
36522; July 30, 2018). However, due to design and schedule changes only
a small portion of that work was conducted under the issued IHA. This
proposed IHA covers one year of a five-year project.
Description of Proposed Activity
Overview
The CTJV has requested authorization for take of marine mammals
incidental to in-water construction activities associated with the PTST
project. The project consists of the construction of a two-lane
parallel tunnel to the west of the existing Thimble Shoal Tunnel,
connecting Portal Island Nos. 1 and 2 of the CBBT facility which
extends across the mouth of the Chesapeake Bay near Virginia Beach,
Virginia. Upon completion, the new tunnel will carry two lanes of
southbound traffic and the existing tunnel will remain in operation and
carry two lanes of northbound traffic. The PTST project will address
existing constraints to regional mobility based on current traffic
volume along the facility. Construction will include the installation
of 878 piles over 188 days as shown below:
180 12-inch timber piles
140 36-inch steel pipe piles
500 36-inch interlocked pipes
58 42-inch steel casings
These will be installed using impact driving, vibratory driving and
drilling with down-the-hole (DTH) hammers. Some piles will be removed
via vibratory hammer. These activities will introduce sound into the
water at levels which are likely to result in behavioral harassment or
auditory injury based on expected marine mammal presence in the area.
In-water construction associated with the project is anticipated to
begin in fall of 2019.
Dates and Duration
Work authorized under the proposed IHA is anticipated to take 188
days and would occur during standard daylight working hours of
approximately 8-12 hours per day depending on the season. In-water work
would occur every month with the exception of September and October.
The PTST project has been divided into four phases over 5 years.
Phase I commenced in June 2017 and consisted of upland pre-tunnel
excavation activities, while Phase IV is scheduled to be completed in
May of 2022. In-water activities are limited to Phase II and,
potentially, Phase IV (if substructure repair work is required at the
fishing pier and/or bridge trestles and abutments).
Specific Geographic Region
The PTST project is located between Portal Island Nos. 1 and 2 of
the CBBT as shown in Figure 1. A tunnel will be bored underneath the
Thimble Shoal Channel connecting the Portal Islands located near the
mouth of the Chesapeake Bay. The CBBT is a 23-mile (37 km) long
facility that connects the Hampton Roads area of Virginia to the
Eastern Shore of Virginia. Water depths within the PTST construction
area range from 0 to 60 ft (18.2 m) below Mean Lower Low Water (MLLW).
The Thimble Shoal Channel is 1,000 ft (305 m) wide, is authorized to a
depth of -55 ft (16.8 m) below MLLW, and is maintained at a depth of 50
ft (15.2 m) MLLW.
[[Page 64849]]
[GRAPHIC] [TIFF OMITTED] TN25NO19.001
Detailed Description of Specific Activity
The PTST project consists of the construction of a two-lane
parallel tunnel to the west of the existing Thimble Shoal Tunnel,
connecting Portal Island Nos. 1 and 2. Construction of the tunnel
structure will begin on Portal Island No. 1 and move from south to
north to Portal Island No. 2.
The tunnel boring machine (TBM) components will be barged and
trucked to Portal Island No. 1. The TBM will be assembled within an
entry/launch portal that will be constructed on Portal Island No. 1.
The machine will then both excavate material and construct the tunnel
as it progresses from Portal Island No. 1 to Portal Island No. 2.
Precast concrete tunnel segments will be transported to the TBM for
installation. The TBM will assemble the tunnel segments in-place as the
tunnel is bored. After the TBM reaches Portal Island No. 2, it will be
disassembled, and the components will be removed via an exit/receiving
portal on Portal Island No. 2. After the tunnel structure is completed,
final upland work for the PTST Project will include installation of the
final roadway, lighting, finishes, mechanical systems, and other
required internal systems for tunnel use and function. In addition, the
existing fishing pier will be repaired and refurbished.
The new parallel two-lane tunnel is 6,350 ft (1935.5 m) in overall
total length with 5,356 linear ft (1632.5 m) located below Mean High
Water (MHW). Descriptions of upland activities may be found in the
application but such actions will not affect marine mammals and are not
described here.
Proposed in-water activities include the following and are shown in
Table 1:
Temporary dock construction: Construction of a 32,832
ft\2\ (3.050 m\2\) working platform on the west side of Portal Island
No. 1. This construction includes temporary in-water installation of 58
36-inch piles. A 42-inch steel casing will initially be drilled with a
DTH hammer for each of the 36-inch piles which will then be installed
with an impact hammer. A bubble curtain will be used during the impact
driving of 47 of the 36-inch piles while 11 piles are expected to be
installed using the impact hammer without a bubble curtain due to water
depth of less than 10 ft.
Mooring dolphins: An estimated 180 12-inch timber piles
will be used for construction of the temporary mooring dolphins (120
piles at Portal Island No. 1 and 60 piles at Portal Island No. 2) and
will be installed and removed using a vibratory hammer. However, should
refusal be encountered prior to design tip elevation when driving with
the vibratory hammer an impact hammer will be used to drive the
remainder of the pile length. No bubble curtains will be utilized for
the installation of the timber piles.
Construction of two temporary Omega trestles: 36 in-water
36-inch diameter steel pipe piles will be installed at Portal Island 1
along with 28 in-water 36-inch diameter steel pipe piles at Island 2.
These trestles will be offset to the west side of each engineered berm,
extending
[[Page 64850]]
approximately 659 ft (231.7 m) channelward from Portal Island Nos. 1
and 2, respectively.
Construction of two engineered berms, approximately 1,395
ft (425 m) in length for Portal Island No. 1 (435 ft (132 m) above MHW
and 960 ft (292 m) below MHW) requiring 256 36-inch steel interlocked
pipe piles (135 on west side; 121 on east side) and approximately 1,354
ft (451 m) in length for Portal Island No. 2 (446 ft (136 m) above MHW
and 908 ft below (277 m) MHW) requiring 244 piles of the same size and
type (129 piles on west side; 115 on east side). Both berms will extend
channelward from each portal island. Construction methods will include
impact pile driving as well as casing advancement by DTH hammer.
Interlocked pipe piles will be installed through the use of DTH
drilling equipment. This equipment uses reverse circulation drilling
techniques in order to advance hollow steel pipes through the existing
rock found within the project site. Reverse circulation drilling is a
process that involves the use of compressed air to power a down-the-
hole hammer drill. In addition to providing the reciprocating action of
the drill, the compressed air also serves to lift the drill cuttings
away from the face of the drill and direct them back into the drill
string where they are collected from the drill system for disposal.
Once the pipes are advanced through the rock layer using the DTH
technology, they are driven to final grade via traditional impact
driving methods.
Vibratory installation and removal of 12 36-inch steel
pipe piles at Portal Island 1 and 16 piles at Portal Island 2 on both
sides of the new tunnel alignment for settlement mitigation, support of
excavation (SOE), and to facilitate flowable fill placement.
Some in-water construction activities would occur
simultaneously. Table 2 depicts concurrent driving scenarios (i.e.,
Impact + DTH; DTH + DTH) and the number of days they are anticipated to
occur at specific locations (i.e. Portal Island 1; Portal Island 2;
Portal Island 1 and Portal Island 2).
Table 1--Pile Driving Activities Associated With the PTST Project
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Number of Days per
Pile location Pile function Pile type Installation/removal Bubble piles activity Days per activity (by hammer
method curtain below MHW (total) type)
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1............. Mooring dolphins..... 12-inch Timber piles. Vibratory (Install).. No............ 120 21 12 Days (10 Piles/Day).
Impact (if needed)... No............ 3 Days (12 Piles/Day).
Vibratory (Removal).. No............ 6 Days (20 Piles/Day).
1............. Temporary Dock....... 42-inch Diameter DTH (install)........ No............ 58 48 29 Days (2 Piles/day).
Steel Pipe Casing. Vibratory (removal).. No............ 19 Days (3 Piles/day).
36-inch Diameter Impact............... Yes........... * 58 29 29 Days (2 Piles/day).
Steel Pipe Pile.
1............. Omega Trestle........ 36-inch Diameter DTH (Install)........ No............ ** 36 78 13 Days (2 Piles/Day).
Steel Pipe Piles.
Impact............... Yes........... 65 Days (0.4 Piles/Day).
1............. Berm Support of 36-inch Diameter DTH (install)........ No............ 135 58 45 Days (3 Piles/Day).
Excavation Wall-- Steel Interlocked
West Side. Pipe Piles.
Impact............... Yes........... 13 Days (10 Piles/Day).
1............. Berm Support of 36-inch Diameter DTH (Install)........ No............ 121 121 80 Days (1.5 Piles/Day).
Excavation Wall-- Steel Interlocked
East Side. Pipe Piles.
Impact............... Yes........... 41 Days (3 Piles/Day).
1............. Mooring Piles and 36-inch Diameter Vibratory (Install & No............ 12 2 2 Days (12 Piles/Day).
Templates. Steel Pipe Piles. Removal).
2............. Mooring Dolphins..... 12-inch Timber Piles. Vibratory (Install).. No............ 60 12 6 Days (10 Piles/Day).
Impact (if needed)... No............ 2 Days (15 Piles/Day).***
Vibratory (Removal).. No............ 4 Days (20 Piles/Day).
2............. Omega Trestle........ 36-inch Diameter DTH (Install)........ No............ 28 28 16 Days (2 Piles/Day).
Steel Pipe Piles.
Impact............... Yes........... 12 Days (2.33 Piles/Day).
2............. Berm Support of 36-inch Diameter DTH (Install)........ No............ 129 55 42 Days (3 Piles/Day).
Excavation Wall-- Steel Interlocked
West Side. Pipe Piles.
Impact............... Yes........... 13 Days (9.5 Piles/Day).
2............. Berm Support of 36-inch Diameter DTH (Install)........ No............ 115 106 71 Days (1.5 Piles/Day).
Excavation Wall-- Steel Interlocked
East Side. Pipe Piles.
Impact............... Yes........... 35 Days (3 Piles/Day).
2............. Mooring Piles and 36-inch Diameter Vibratory (Install & No............ 16 4 4 Days (4 Piles/Day).
Templates. Steel Pipe Piles. Removal).
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Total..... ..................... ..................... ..................... .............. 878
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* 11 piles will be installed in <10 ft water so bubble curtain will not be used.
** 10 piles will be installed in <10 ft water so bubble curtain will not be used.
Table 2--Concurrent Driving Scenarios for PTST Project
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Number of days
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Concurrent driving scenarios Driving at Portal
Island 1 Island 2 Island 1 and
Portal Island 2 *
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Impact + DTH........................................... 13 14 13
DTH + DTH.............................................. 22 11 17
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* Single hammer at each portal island.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (https://www.fisheries.noaa.gov/find-species).
Table 3 lists all species with expected potential for occurrence
near the project area and summarizes information related to the
population or stock, including regulatory status under the
[[Page 64851]]
MMPA and ESA and potential biological removal (PBR), where known. For
taxonomy, we follow Committee on Taxonomy (2018). PBR is defined by the
MMPA as the maximum number of animals, not including natural
mortalities, that may be removed from a marine mammal stock while
allowing that stock to reach or maintain its optimum sustainable
population (as described in NMFS's SARs). While no mortality is
anticipated or authorized here, PBR and annual serious injury and
mortality from anthropogenic sources are included here as gross
indicators of the status of the species and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS's stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS's United States Atlantic and Gulf of Mexico Marine Mammal Stock
Assessments (Hayes et al. 2019). All values presented in Table 3 are
the most recent available at the time of publication and are available
in the 2018 SARs (Hayes et al. 2019).
Table 3--Marine Mammal Species Likely To Occur Near the Project Area
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ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenidae:
North Atlantic right whale \7\.. Eubalaena glacialis.... Western North Atlantic E, D; Y 451 (0, 411 \4\; 2017) 0.9 5.56
(WNA).
Family Balaenopteridae (rorquals):
Humpback whale \5\.............. Megaptera novaeangliae. Gulf of Maine.......... -,-; N 896 (.42; 896; 2012).. 14.6 9.7
Fin whale \7\................... Balaenoptera physalus.. WNA.................... E,D; Y 1,618 (0.33; 1,234; 2.5 2.5
2011.
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Bottlenose dolphin.............. Tursiops truncatus..... WNA Coastal, Northern -,-; Y 6,639 (0.41; 4,759; 48 6.1-13.2
Migratory. 2011).
WNA Coastal, Southern -,-; Y 7,751 (0.06; 2,353; 23 0-14.3
Migratory. 2011).
Northern North Carolina -,-; Y 823 (0.06; 782; 2013). 7.8 0.8-18.2
Estuarine System.
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Maine/Bay of -, -; N 79,833 (0.32; 61,415; 706 256
Fundy. 2011).
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Order Carnivora--Superfamily Pinnipedia
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Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... WNA.................... -; N 75,834 (0.1; 66,884, 2,006 345
2012).
Gray seal \6\................... Halichoerus grypus..... WNA.................... -; N 27,131 (0.19, 23,158, 1,359 5,688
2016).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ For the North Atlantic right whale the best available abundance estimate is derived from the 2018 North Atlantic Right Whale Consortium 2018 Annual
Report Card (Pettis et al. 2018).
\5\ 2018 U.S. Atlantic SAR for the Gulf of Maine feeding population lists a current abundance estimate of 896 individuals. However, we note that the
estimate is defined on the basis of feeding location alone (i.e., Gulf of Maine) and is therefore likely an underestimate.
\6\ The NMFS stock abundance estimate applies to U.S. population only, however the actual stock abundance is approximately 505,000.
\7\ Species are not expected to be taken or proposed for authorization.
All species that could potentially occur in the proposed survey
areas are included in Table 3. However, the temporal and/or spatial
occurrence of North Atlantic right whale and fin whale is such that
take is not expected to occur, and they are not discussed further
beyond the explanation provided here. Between 1998 and 2013, there were
no reports of North Atlantic right whale strandings within the
Chesapeake Bay and only four reported standings along the coast of
Virginia. During this same period, only six fin whale strandings were
recorded within the Chesapeake Bay (Barco and Swingle 2014). There were
no reports of fin whale strandings (Swingle et al. 2017) in 2016. Due
to the low occurrence of North Atlantic right whales and fin whales,
NMFS is not proposing to authorize take of these species. There are
also few reported sightings or observations of either species in the
Bay. Since June 7, 2017, elevated North Atlantic right whale
mortalities have been documented, primarily in Canada, and were
declared an Unusual Mortality Event (UME). As of September 30, 2019,
only a single right whale mortality has been documented this year,
which occurred offshore of Virginia Beach, VA and was caused by chronic
[[Page 64852]]
entanglement. Due to the low occurrence of North Atlantic right whales
and fin whales, NMFS is not proposing to authorize take of these
species.
Cetaceans
Humpback Whale
The humpback whale is found worldwide in all oceans. Humpbacks
occur off southern New England in all four seasons, with peak abundance
in spring and summer. In winter, humpback whales from waters off New
England, Canada, Greenland, Iceland, and Norway migrate to mate and
calve primarily in the West Indies (including the Antilles, the
Dominican Republic, the Virgin Islands and Puerto Rico), where spatial
and genetic mixing among these groups occurs.
For the humpback whale, NMFS defines a stock on the basis of
feeding location, i.e., Gulf of Maine. However, our reference to
humpback whales in this document refers to any individuals of the
species that are found in the specific geographic region. These
individuals may be from the same breeding population (e.g., West Indies
breeding population of humpback whales) but visit different feeding
areas.
Based on photo-identification only 39 percent of individual
humpback whales observed along the mid- and south Atlantic U.S. coast
are from the Gulf of Maine stock (Barco et al., 2002). Therefore, the
SAR abundance estimate underrepresents the relevant population, i.e.,
the West Indies breeding population.
Prior to 2016, humpback whales were listed under the ESA as an
endangered species worldwide. Following a 2015 global status review
(Bettridge et al., 2015), NMFS established 14 DPSs with different
listing statuses (81 FR 62259; September 8, 2016) pursuant to the ESA.
The West Indies DPS, which consists of the whales whose breeding range
includes the Atlantic margin of the Antilles from Cuba to northern
Venezuela, and whose feeding range primarily includes the Gulf of
Maine, eastern Canada, and western Greenland, was delisted. As
described in Bettridge et al. (2015), the West Indies DPS has a
substantial population size (i.e., approximately 10,000; Stevick et
al., 2003; Smith et al., 1999; Bettridge et al., 2015), and appears to
be experiencing consistent growth. Humpback whales are the only large
cetaceans that are likely to occur in the project area and could be
found there at any time of the year. There have been 33 humpback whale
strandings recorded in Virginia between 1988 and 2013. Most of these
strandings were reported from ocean facing beaches, but 11 were also
within the Chesapeake Bay (Barco and Swingle 2014). Strandings occurred
in all seasons, but were most common in the spring.
Since January 2016, elevated humpback whale mortalities have
occurred along the Atlantic coast from Maine through Florida. The event
has been declared a UME with 105 strandings recorded, 7 of which
occurred in or near the mouth of the Chesapeake Bay. Partial or full
necropsy examinations have been conducted on approximately half of the
known cases. A portion of the whales have shown evidence of pre-mortem
vessel strike; however, this finding is not consistent across all of
the whales examined so more research is needed. NOAA is consulting with
researchers that are conducting studies on the humpback whale
populations, and these efforts may provide information on changes in
whale distribution and habitat use that could provide additional
insight into how these vessel interactions occurred. More detailed
information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2019-humpback-whale-unusual-mortality-event-along-atlantic-coast. Three previous UMEs involving humpback whales
have occurred since 2000, in 2003, 2005, and 2006.
Humpback whales use the mid-Atlantic as a migratory pathway to and
from the calving/mating grounds, but it may also be an important winter
feeding area for juveniles. Since 1989, observations of juvenile
humpbacks in the mid-Atlantic have been increasing during the winter
months, peaking from January through March (Swingle et al. 1993).
Biologists theorize that non-reproductive animals may be establishing a
winter feeding range in the mid-Atlantic since they are not
participating in reproductive behavior in the Caribbean. Swingle et al.
(1993) identified a shift in distribution of juvenile humpback whales
in the nearshore waters of Virginia, primarily in winter months.
Identified whales using the mid-Atlantic area were found to be
residents of the Gulf of Maine and Atlantic Canada (Gulf of St.
Lawrence and Newfoundland) feeding groups; suggesting a mixing of
different feeding populations in the Mid-Atlantic region.
Bottlenose Dolphin
The bottlenose dolphin occurs in temperate and tropical oceans
throughout the world, ranging in latitudes from 45[deg] N to 45[deg] S
(Blaylock 1985). In the western Atlantic Ocean there are two distinct
morphotypes of bottlenose dolphins, an offshore type that occurs along
the edge of the continental shelf as well as an inshore type. The
inshore morphotype can be found along the entire United States coast
from New York to the Gulf of Mexico, and typically occurs in waters
less than 20 meters deep (NOAA Fisheries 2016a). Bottlenose dolphins
found in Virginia are representative primarily of either the northern
migratory coastal stock, southern migratory coastal stock, or the
Northern North Carolina Estuarine System Stock (NNCES).
The northern migratory coastal stock is best defined by its
distribution during warm water months when the stock occupies coastal
waters from the shoreline to approximately the 20-m isobath between
Assateague, Virginia, and Long Island, New York (Garrison et al.
2017b). The stock migrates in late summer and fall and, during cold
water months (best described by January and February), occupies coastal
waters from approximately Cape Lookout, North Carolina, to the North
Carolina/Virginia border (Garrison et al. 2017b). Historically, common
bottlenose dolphins have been rarely observed during cold water months
in coastal waters north of the North Carolina/Virginia border, and
their northern distribution in winter appears to be limited by water
temperatures. Overlap with the southern migratory coastal stock in
coastal waters of northern North Carolina and Virginia is possible
during spring and fall migratory periods, but the degree of overlap is
unknown and it may vary depending on annual water temperature (Garrison
et al. 2016). When the stock has migrated in cold water months to
coastal waters from just north of Cape Hatteras, North Carolina, to
just south of Cape Lookout, North Carolina, it overlaps spatially with
the Northern North Carolina Estuarine System (NNCES) Stock (Garrison et
al. 2017b).
The southern migratory coastal stock migrates seasonally along the
coast between North Carolina and northern Florida (Garrison et al.
2017b). During January-March, the southern migratory coastal stock
appears to move as far south as northern Florida. During April-June,
the stock moves back north past Cape Hatteras, North Carolina (Garrison
et al. 2017b), where it overlaps, in coastal waters, with the NNCES
stock (in waters <=1 km from shore). During the warm water months of
July-August, the stock is presumed to occupy coastal waters north of
Cape Lookout, North Carolina, to Assateague, Virginia, including the
Chesapeake Bay.
[[Page 64853]]
The NNCES stock is best defined as animals that occupy primarily
waters of the Pamlico Sound estuarine system (which also includes Core,
Roanoke, and Albemarle sounds, and the Neuse River) during warm water
months (July-August). Members of this stock also use coastal waters
(<=1 km from shore) of North Carolina from Beaufort north to Virginia
Beach, Virginia, including the lower Chesapeake Bay. A community of
NNCES dolphins are likely year-round Bay residents (Patterson, Pers.
Comm).
Harbor Porpoise
The harbor porpoise is typically found in colder waters in the
northern hemisphere. In the western North Atlantic Ocean, harbor
porpoises range from Greenland to as far south as North Carolina (Barco
and Swingle 2014). They are commonly found in bays, estuaries, and
harbors less than 200 meters deep (NOAA Fisheries 2017c). Harbor
porpoises in the United States are made up of the Gulf of Main/Bay of
Fundy stock. Gulf of Main/Bay of Fundy stock are concentrated in the
Gulf of Maine in the summer, but are widely dispersed from Maine to New
Jersey in the winter. South of New Jersey, harbor porpoises occur at
lower densities. Migrations to and from the Gulf of Maine do not follow
a defined route. (NOAA Fisheries 2016c).
Harbor porpoise occur seasonally in the winter and spring in small
numbers. Strandings occur primarily on ocean facing beaches, but they
occasionally travel into the Chesapeake Bay to forage and could occur
in the project area (Barco and Swingle 2014). Since 1999, stranding
incidents have ranged widely from a high of 40 in 1999 to 2 in 2011,
2012, and 2016 (Barco et al. 2017).
Pinnipeds
Harbor Seal
The harbor seal occurs in arctic and temperate coastal waters
throughout the northern hemisphere, including on both the east and west
coasts of the United States. On the east coast, harbor seals can be
found from the Canadian Arctic down to Georgia (Blaylock 1985). Harbor
seals occur year-round in Canada and Maine and seasonally (September-
May) from southern New England to New Jersey (NOAA Fisheries 2016d).
The range of harbor seals appears to be shifting as they are regularly
reported further south than they were historically. In recent years,
they have established haul out sites in the Chesapeake Bay including on
the portal islands of the CBBT (Rees et al. 2016, Jones et al. 2018).
Harbor seals are the most common seal in Virginia (Barco and
Swingle 2014). They can be seen resting on the rocks around the portal
islands of the CBBT from December through April. Seal observation
surveys conducted at the CBBT recorded 112 seals during the 2014/2015
season, 184 seals during the 2015/2016 season, 308 seals in the 2016/
2017 season and 340 seals during the 2017/2018 season. They are
primarily concentrated north of the project area at Portal Island No. 3
(Rees et al 2016; Jones et al. 2018).
Gray Seal
The gray seal occurs on both coasts of the Northern Atlantic Ocean
and are divided into three major populations (NOAA Fisheries 2016b).
The western north Atlantic stock occurs in eastern Canada and the
northeastern United States, occasionally as far south as North
Carolina. Gray seals inhabit rocky coasts and islands, sandbars, ice
shelves and icebergs (NOAA Fisheries 2016b). In the United States, gray
seals congregate in the summer to give birth at four established
colonies in Massachusetts and Maine (NOAA Fisheries 2016b). From
September through May, they disperse and can be abundant as far south
as New Jersey. The range of gray seals appears to be shifting as they
are regularly being reported further south than they were historically
(Rees et al. 2016).
Gray seals are uncommon in Virginia and the Chesapeake Bay. Only 15
gray seal strandings were documented in Virginia from 1988 through 2013
(Barco and Swingle 2014). They are rarely found resting on the rocks
around the portal islands of the CBBT from December through April
alongside harbor seals. Seal observation surveys conducted at the CBBT
recorded one gray seal in each of the 2014/2015 and 2015/2016 seasons
while no gray seals were reported during the 2016/2017 and 2017/2018
seasons (Rees et al. 2016, Jones et al. 2018).
Habitat
No ESA-designated critical habitat overlaps with the project area.
A migratory Biologically Important Area (BIA) for North Atlantic right
whales is found offshore of the mouth of the Chesapeake Bay but does
not overlap with the project area. As previously described, right
whales are rarely observed in the Bay and sound from the proposed in-
water activities are not anticipated to propagate outside of the Bay to
the boundary of the designated BIA.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et al.
1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 4.
Table 4--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
[[Page 64854]]
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al. 2006; Kastelein et al. 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Five marine mammal species (3 cetacean and 2 phocid pinniped) have the
reasonable potential to co-occur with the proposed survey activities.
Please refer to Table 3. Of the cetacean species that may be present,
one is classified as low-frequency (humpback whale), one is classified
as mid-frequency (bottlenose dolphin) and one is classified as high-
frequency (harbor porpoise).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take by Incidental Harassment section
later in this document includes a quantitative analysis of the number
of individuals that are expected to be taken by this activity. The
Negligible Impact Analysis and Determination section considers the
content of this section, the Estimated Take by Incidental Harassment
section, and the Proposed Mitigation section, to draw conclusions
regarding the likely impacts of these activities on the reproductive
success or survivorship of individuals and how those impacts on
individuals are likely to impact marine mammal species or stocks.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far. The sound level of an area is defined by the
total acoustical energy being generated by known and unknown sources.
These sources may include physical (e.g., waves, wind, precipitation,
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced
by marine mammals, fish, and invertebrates), and anthropogenic sound
(e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al. 1995). The result is that, depending
on the source type and its intensity, sound from the specified activity
may be a negligible addition to the local environment or could form a
distinctive signal that may affect marine mammals.
In-water construction activities associated with the project would
include impact pile driving, vibratory pile driving, vibratory pile
removal, and drilling with a DTH hammer. The sounds produced by these
activities fall into one of two general sound types: Impulsive and non-
impulsive. Impulsive sounds (e.g., explosions, gunshots, sonic booms,
impact pile driving) are typically transient, brief (less than 1
second), broadband, and consist of high peak sound pressure with rapid
rise time and rapid decay (ANSI 1986; NIOSH 1998; NMFS 2018). Non-
impulsive sounds (e.g. aircraft, machinery operations such as drilling
or dredging, vibratory pile driving, and active sonar systems) can be
broadband, narrowband or tonal, brief or prolonged (continuous or
intermittent), and typically do not have the high peak sound pressure
with raid rise/decay time that impulsive sounds do (ANSI 1995; NIOSH
1998; NMFS 2018). The distinction between these two sound types is
important because they have differing potential to cause physical
effects, particularly with regard to hearing (e.g., Ward 1997 in
Southall et al. 2007).
Impact hammers operate by repeatedly dropping a heavy piston onto a
pile to drive the pile into the substrate. Sound generated by impact
hammers is characterized by rapid rise times and high peak levels, a
potentially injurious combination (Hastings and Popper 2005). Vibratory
hammers install piles by vibrating them and allowing the weight of the
hammer to push them into the sediment. Vibratory hammers produce
significantly less sound than impact hammers. Peak sound pressure
levels (SPLs) may be 180 dB or greater, but are generally 10 to 20 dB
lower than SPLs generated during impact pile driving of the same-sized
pile (Oestman et al. 2009). Rise time is slower, reducing the
probability and severity of injury, and sound energy is distributed
over a greater amount of time (Nedwell and Edwards 2002; Carlson et al.
2005). A DTH hammer is used to place hollow steel piles or casings by
drilling. A DTH hammer is a drill bit that drills through the bedrock
using a pulse mechanism that functions at the bottom of the hole. This
pulsing bit breaks up rock to allow removal of debris and insertion of
the pile. The head extends so that the drilling takes place below the
pile. Sound associated with DTH has both continuous and impulsive
characteristics and may be appropriately characterized one way or the
other depending on the operating parameters and settings that are
utilized on a specific device. CTJV conducted sound
[[Page 64855]]
source verification (SSV) monitoring prior to the expiration of the
previous IHA and determined that impulsive characteristics were
predominant as the equipment was employed at the PTST project location
(Denes et al. 2019).
The likely or possible impacts of CTJV's proposed activity on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, any impacts to marine
mammals are expected to primarily be acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
installation.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving is the primary means by which marine
mammals may be harassed from CTJV's specified activity. In general,
animals exposed to natural or anthropogenic sound may experience
physical and psychological effects, ranging in magnitude from none to
severe (Southall et al. 2007). Exposure to in-water construction noise
has the potential to result in auditory threshold shifts and behavioral
reactions (e.g., avoidance, temporary cessation of foraging and
vocalizing, changes in dive behavior) and/or lead to non-observable
physiological responses such an increase in stress hormones
((Richardson et al. 1995; Gordon et al. 2004; Nowacek et al.2007;
Southall et al. 2007; Gotz et al. 2009). Additional noise in a marine
mammal's habitat can mask acoustic cues used by marine mammals to carry
out daily functions such as communication and predator and prey
detection. The effects of pile driving noise on marine mammals are
dependent on several factors, including, but not limited to, sound type
(e.g., impulsive vs. non-impulsive), the species, age and sex class
(e.g., adult male vs. mom with calf), duration of exposure, the
distance between the pile and the animal, received levels, behavior at
time of exposure, and previous history with exposure (Wartzok et al.
2004; Southall et al. 2007). Here we discuss physical auditory effects
(threshold shifts), followed by behavioral effects and potential
impacts on habitat.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur, in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal, but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the masking zone may be highly variable in size.
We describe the more severe effects (i.e., permanent hearing
impairment, certain non-auditory physical or physiological effects)
only briefly as we do not expect that there is a reasonable likelihood
that CTJV's activities would result in such effects (see below for
further discussion). NMFS defines a noise-induced threshold shift (TS)
as a change, usually an increase, in the threshold of audibility at a
specified frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (2018), there are numerous factors
to consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how animal uses sound within the
frequency band of the signal; e.g., Kastelein et al. 2014b), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). Available data from
humans and other terrestrial mammals indicate that a 40 dB threshold
shift approximates PTS onset (see Ward et al. 1958, 1959; Ward 1960;
Kryter et al. 1966; Miller 1974; Ahroon et al. 1996; Henderson et al.
2008). PTS levels for marine mammals are estimates, as with the
exception of a single study unintentionally inducing PTS in a harbor
seal (Kastak et al. 2008), there are no empirical data measuring PTS in
marine mammals largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels
inducing PTS are not typically pursued or authorized (NMFS 2018).
Temporary Threshold Shift (TTS)--A temporary, reversible increase
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS 2018). Based on data from cetacean TTS measurements (see
Southall et al. 2007), a TTS of 6 dB is considered the minimum
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et
al. 2000; Finneran et al. 2000, 2002). As described in Finneran (2016),
marine mammal studies have shown the amount of TTS increases with
cumulative sound exposure level (SELcum) in an accelerating fashion: At
low exposures with lower SELcum, the amount of TTS is typically small
and the growth curves have shallow slopes. At exposures with higher
SELcum, the growth curves become steeper and approach linear
relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al. 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale (Delphinapterus
[[Page 64856]]
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis)) and five species of pinnipeds exposed to a limited
number of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al. 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran 2015). Additionally, the existing marine mammal TTS data come
from a limited number of individuals within these species. No data are
available on noise-induced hearing loss for mysticetes. For summaries
of data on TTS in marine mammals or for further discussion of TTS onset
thresholds, please see Southall et al. (2007), Finneran and Jenkins
(2012), Finneran (2015), and Table 5 in NMFS (2018).
Behavioral Harassment--Behavioral disturbance may include a variety
of effects, including subtle changes in behavior (e.g., minor or brief
avoidance of an area or changes in vocalizations), more conspicuous
changes in similar behavioral activities, and more sustained and/or
potentially severe reactions, such as displacement from or abandonment
of high-quality habitat. Disturbance may result in changing durations
of surfacing and dives, number of blows per surfacing, or moving
direction and/or speed; reduced/increased vocal activities; changing/
cessation of certain behavioral activities (such as socializing or
feeding); visible startle response or aggressive behavior (such as
tail/fluke slapping or jaw clapping); avoidance of areas where sound
sources are located. Pinnipeds may increase their haul out time,
possibly to avoid in-water disturbance (Thorson and Reyff 2006).
Behavioral responses to sound are highly variable and context-specific
and any reactions depend on numerous intrinsic and extrinsic factors
(e.g., species, state of maturity, experience, current activity,
reproductive state, auditory sensitivity, time of day), as well as the
interplay between factors (e.g., Richardson et al. 1995; Wartzok et al.
2003; Southall et al. 2007; Weilgart 2007; Archer et al. 2010).
Behavioral reactions can vary not only among individuals but also
within an individual, depending on previous experience with a sound
source, context, and numerous other factors (Ellison et al. 2012), and
can vary depending on characteristics associated with the sound source
(e.g., whether it is moving or stationary, number of sources, distance
from the source). In general, pinnipeds seem more tolerant of, or at
least habituate more quickly to, potentially disturbing underwater
sound than do cetaceans, and generally seem to be less responsive to
exposure to industrial sound than most cetaceans. Please see Appendices
B-C of Southall et al. (2007) for a review of studies involving marine
mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al. 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al. 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.
1995; NRC, 2003; Wartzok et al. 2003). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al. 1997;
Finneran et al. 2003). Observed responses of wild marine mammals to
loud pulsed sound sources (typically seismic airguns or acoustic
harassment devices) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds 2002; see also Richardson et al. 1995; Nowacek et al. 2007).
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. 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; NRC 2005).
However, 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 breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely, and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark 2000; Costa et al. 2003; Ng and Leung 2003; Nowacek et al.
2004; Goldbogen et al. 2013a,b). Variations in dive behavior may
reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
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). A
determination of whether foraging disruptions incur fitness
consequences would require 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.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the tolerance of underwater noise
when
[[Page 64857]]
determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al. 2001, 2005b, 2006; Gailey et al.
2007).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al,
2000; Fristrup et al. 2003; Foote et al, 2004), while right whales have
been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al, 2007b). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al, 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al. 1995). For example, gray whales
(Eschrictius robustus) are known to change direction--deflecting from
customary migratory paths--in order to avoid noise from seismic surveys
(Malme et al. 1984). Avoidance may be short-term, with animals
returning to the area once the noise has ceased (e.g., Bowles et al.
1994; Goold 1996; Stone et al. 2000; Morton and Symonds, 2002; Gailey
et al. 2007). Longer-term displacement is possible, however, which may
lead to changes in abundance or distribution patterns of the affected
species in the affected region if habituation to the presence of the
sound does not occur (e.g., Blackwell et al. 2004; Bejder et al. 2006;
Teilmann et al. 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus 1996). The result of a flight response could range from brief,
temporary exertion and displacement from the area where the signal
provokes flight to, in extreme cases, marine mammal strandings (Evans
and England 2001). However, it should be noted that response to a
perceived predator does not necessarily invoke flight (Ford and Reeves
2008), and whether individuals are solitary or in groups may influence
the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil 1997; Fritz et al, 2002; Purser and Radford 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al. 1996; Bradshaw et al. 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al. 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al. 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
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
[[Page 64858]]
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).
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, 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. Busy ship channels
traverse Thimble Shoal. Commercial vessels including container ships
and cruise ships as well as numerous recreational frequent the area, so
background sound levels near the PTST project area are likely to be
elevated, although to what degree is unknown.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al. 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al. 2000;
Foote et al. 2004; Parks et al. 2007b; Di Iorio and Clark 2009; Holt et
al. 2009). Masking can be reduced in situations where the signal and
noise come from different directions (Richardson et al. 1995), through
amplitude modulation of the signal, or through other compensatory
behaviors (Houser and Moore 2014). Masking can be tested directly in
captive species (e.g., Erbe 2008), but in wild populations it must be
either modeled or inferred from evidence of masking compensation. There
are few studies addressing real-world masking sounds likely to be
experienced by marine mammals in the wild (e.g., Branstetter et al.
2013).
Masking affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand 2009). All anthropogenic sound sources, but especially
chronic and lower-frequency signals (e.g., from vessel traffic),
contribute to elevated ambient sound levels, thus intensifying masking.
Underwater Acoustic Effects
Potential Effects of Pile Driving Sound
The effects of sounds from pile driving might include one or more
of the following: Temporary or permanent hearing impairment, non-
auditory physical or physiological effects, behavioral disturbance, and
masking (Richardson et al. 1995; Gordon et al. 2003; Nowacek et al.
2007; Southall et al. 2007). The effects of pile driving on marine
mammals are dependent on several factors, including the type and depth
of the animal; the pile size and type, and the intensity and duration
of the pile driving sound; the substrate; the standoff distance between
the pile and the animal; and the sound propagation properties of the
environment. Impacts to marine mammals from pile driving activities are
expected to result primarily from acoustic pathways. As such, the
degree of effect is intrinsically related to the frequency, received
level, and duration of the sound exposure, which are in turn influenced
by the distance between the animal and the source. The further away
from the source, the less intense the exposure should be. The substrate
and depth of the habitat affect the sound propagation properties of the
environment. In addition, substrates that are soft (e.g., sand) would
absorb or attenuate the sound more readily than hard substrates (e.g.,
rock), which may reflect the acoustic wave. Soft porous substrates
would also likely require less time to drive the pile, and possibly
less forceful equipment, which would ultimately decrease the intensity
of the acoustic source.
In the absence of mitigation, impacts to marine species could be
expected to include physiological and behavioral responses to the
acoustic signature (Viada et al. 2008). Potential effects from
impulsive sound sources like impact pile driving can range in severity
from effects such as behavioral disturbance to temporary or permanent
hearing impairment (Yelverton et al. 1973). Due to the nature of the
pile driving sounds in the project, behavioral disturbance is the most
likely effect from the proposed activity. Marine mammals exposed to
high intensity sound repeatedly or for prolonged periods can experience
hearing threshold shifts. Note that PTS constitutes injury, but TTS
does not (Southall et al. 2007).
Non-Auditory Physiological Effects
Non-auditory physiological effects or injuries that theoretically
might occur in marine mammals exposed to strong underwater sound
include stress, neurological effects, bubble formation, resonance
effects, and other types of organ or tissue damage (Cox et al. 2006;
Southall et al. 2007). Studies examining such effects are limited. In
general, little is known about the potential for pile driving to cause
non-auditory physical effects in marine mammals. Available data suggest
that such effects, if they occur at all, would presumably be limited to
short distances from the sound source and to activities that extend
over a prolonged period. The available data do not allow identification
of a specific exposure level above which non-auditory effects can be
expected (Southall et al. 2007) or any meaningful quantitative
predictions of the numbers (if any) of marine mammals that might be
affected in those ways. We do not expect any non-auditory physiological
effects because of mitigation that prevents animals from approach the
source too closely. Marine mammals that show behavioral avoidance of
pile driving, including some odontocetes and some pinnipeds,
[[Page 64859]]
are especially unlikely to incur non-auditory physical effects.
Disturbance Reactions
Responses to continuous sound, such as vibratory pile installation,
have not been documented as well as responses to pulsed sounds. With
both types of pile driving, it is likely that the onset of pile driving
could result in temporary, short term changes in an animal's typical
behavior and/or avoidance of the affected area. These behavioral
changes may include (Richardson et al. 1995): Changing durations of
surfacing and dives, number of blows per surfacing, or moving direction
and/or speed; reduced/increased vocal activities; changing/cessation of
certain behavioral activities (such as socializing or feeding); visible
startle response or aggressive behavior (such as tail/fluke slapping or
jaw clapping); avoidance of areas where sound sources are located; and/
or flight responses (e.g., pinnipeds flushing into water from haul-outs
or rookeries). Pinnipeds may increase their haul out time, possibly to
avoid in-water disturbance (Thorson and Reyff 2006). If a marine mammal
responds to a stimulus by changing its behavior (e.g., through
relatively minor changes in locomotion direction/speed or vocalization
behavior), the response may or may not constitute taking at the
individual level, and is unlikely to affect the stock or the species as
a whole. However, if a sound source displaces marine mammals from an
important feeding or breeding area for a prolonged period, impacts on
animals, and if so potentially on the stock or species, could
potentially be significant (e.g., Lusseau and Bejder 2007; Weilgart
2007).
The biological significance of many of these behavioral
disturbances is difficult to predict, especially if the detected
disturbances appear minor. However, the consequences of behavioral
modification could be expected to be biologically significant if the
change affects growth, survival, or reproduction. Significant
behavioral modifications that could potentially lead to effects on
growth, survival, or reproduction include:
Drastic changes in diving/surfacing patterns (such as
those thought to cause beaked whale stranding due to exposure to
military mid-frequency tactical sonar);
Longer-term habitat abandonment due to loss of desirable
acoustic environment; and
Longer-term cessation of feeding or social interaction.
The onset of behavioral disturbance from anthropogenic sound
depends on both external factors (characteristics of sound sources and
their paths) and the specific characteristics of the receiving animals
(hearing, motivation, experience, demography) and is difficult to
predict (Southall et al. 2007).
Auditory Masking
Natural and artificial sounds can disrupt behavior by masking. The
frequency range of the potentially masking sound is important in
determining any potential behavioral impacts. Because sound generated
from in-water pile driving is mostly concentrated at low frequency
ranges, it may have less effect on high frequency echolocation sounds
made by porpoises. The most intense underwater sounds in the proposed
action are those produced by impact pile driving. Given that the energy
distribution of pile driving covers a broad frequency spectrum, sound
from these sources would likely be within the audible range of marine
mammals present in the project area. Impact pile driving and DTH
drilling activities are relatively short-term, with rapid pulses
occurring for less than fifteen minutes per pile. The probability for
impact pile driving and DTH drilling resulting from this proposed
action masking acoustic signals important to the behavior and survival
of marine mammal species is low. Vibratory pile driving is also
relatively short-term, with rapid oscillations occurring for
approximately 30 minutes per pile. It is possible that vibratory pile
driving resulting from this proposed action may mask acoustic signals
important to the behavior and survival of marine mammal species, but
the short-term duration and limited affected area would result in
insignificant impacts from masking. Any masking event that could
possibly rise to Level B harassment under the MMPA would occur
concurrently within the zones of behavioral harassment already
estimated for vibratory and impact pile driving, and which have already
been taken into account in the exposure analysis. Active pile driving
is anticipated to occur for up to 8 hours per day for 188 days, but we
do not anticipate masking to significantly affect marine mammals for
the reasons listed above.
Airborne Acoustic Effects
Pinnipeds that occur near the project site could be exposed to
airborne sounds associated with pile driving 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. Only limited numbers of
pinnipeds have used Portal Island 1 and 2 as haulouts (<6 percent of
total pinniped sightings). The majority of hauled out pinniped
sightings have been found at Portal Island 3 (~90 percent) according to
Jones et al. (2018), which is 6 km north of Portal Island 2. This is
far beyond the distance at which harassment could occur due to airborne
noise.
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
previously have been `taken' because of exposure to underwater sound
above the behavioral harassment thresholds, which are in all cases
larger than those associated with airborne sound. Thus, the behavioral
harassment of these animals would already accounted for in these
estimates of potential take. Therefore, we do not believe that
authorization of incidental take resulting from airborne sound for
pinnipeds is warranted, and airborne sound is not discussed further
here.
Marine Mammal Habitat Effects
The area likely impacted by the project is relatively small
compared to the available habitat for all impacted species and stocks,
and does not include any ESA-designated critical habitat. As previously
mentioned, no BIAs overlap with the project area. CTJV's proposed
construction activities would not result in permanent negative impacts
to habitats used directly by marine mammals, but could have localized,
temporary impacts on marine mammal habitat including their prey by
increasing underwater and airborne SPLs and slightly decreasing water
quality. Increased noise levels may affect acoustic habitat (see
masking discussion above) and adversely affect marine mammal prey in
the vicinity of the project area (see discussion below). During pile
driving, elevated levels of underwater noise would ensonify areas
[[Page 64860]]
near the project where both fish and mammals occur and could affect
foraging success.
There are no known foraging hotspots or other ocean bottom
structure of significant biological importance to marine mammals
present in the marine waters of the project area. Therefore, the main
impact issue associated with the proposed activity would be temporarily
elevated sound levels and the associated direct effects on marine
mammals, as discussed previously in this document. The primary
potential acoustic impacts to marine mammal habitat are associated with
elevated sound levels produced by impact, vibratory, and DTH pile
installation as well as vibratory pile removal in the project area.
Physical impacts to the environment such as construction debris are
unlikely.
In-water pile driving would also cause short-term effects on water
quality due to increased turbidity. CTJV would employ standard
construction best management practices to reducing any potential
impacts. Therefore, the impact from increased turbidity levels is
expected to be discountable.
In-Water Construction Effects on Potential Foraging Habitat
Pile installation may temporarily increase turbidity resulting from
suspended sediments. Any increases would be temporary, localized, and
minimal. In general, turbidity associated with pile installation is
localized to about a 25-foot (7.6 m) radius around the pile (Everitt et
al. 1980). Large cetaceans are not expected to be close enough to the
project activity areas to experience effects of turbidity, and any
small cetaceans and pinnipeds could avoid localized areas of turbidity.
Therefore, the impact from increased turbidity levels is expected to be
discountable to marine mammals.
Essential Fish Habitat (EFH) for several species or groups of
species overlaps with the project area including: Little skate,
Atlantic herring, red hake, windowpane flounder, winter skate,
clearnose skate, sandbar shark, sand tiger shark, bluefish, Atlantic
butterfish, scup, summer flounder, and black sea bass. Use of soft
start procedure and bubble curtains will reduce the impacts of
underwater acoustic noise to fish from pile driving activities.
Avoidance by potential prey (i.e., fish) of the immediate area due to
the temporary loss of this foraging habitat is also possible. The
duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. 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.
In-water Construction Effects on Potential Prey (Fish)--
Construction activities would produce continuous (i.e., vibratory pile
driving and removal) and pulsed (i.e., impact driving, DTH) sounds.
Fish react to sounds that are especially strong and/or intermittent
low-frequency sounds. Short duration, sharp sounds can cause overt or
subtle changes in fish behavior and local distribution (summarized in
Popper and Hastings 2009). Hastings and Popper (2005) reviewed several
studies that suggest fish may relocate to avoid certain areas of sound
energy. Additional studies have documented physical and behavioral
effects of pile driving on fish, although several are based on studies
in support of large, multiyear bridge construction projects (e.g.,
Scholik and Yan 2001, 2002; Popper and Hastings 2009). Sound pulses at
received levels of 160 dB may cause subtle changes in fish behavior.
SPLs of 180 dB may cause noticeable changes in behavior (Pearson et al.
1992; Skalski et al. 1992). SPLs of sufficient strength have been known
to cause injury to fish and fish mortality (summarized in Popper et al.
2014).
The most likely impact to fish 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, distribution and
behavior is anticipated. In general, impacts to marine mammal prey
species are expected to be minor and temporary.
In summary, given the relatively small areas being affected, pile
driving activities associated with the proposed action are not likely
to have a permanent, adverse effect on any fish habitat, or populations
of fish species. Thus, we conclude that impacts of the specified
activity 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 this IHA, which will inform both
NMFS' consideration of small numbers and the negligible impact
determination.
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 acoustic sources (i.e., impact driving, vibratory driving and
removal, DTH drilling) 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 cetacean species and phocid pinnipeds because
predicted auditory injury zones are larger than for low-frequency and
mid-frequency species. The proposed mitigation and monitoring measures
are expected to minimize the severity of such taking to the extent
practicable.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
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)
and the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of 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
estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed 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
[[Page 64861]]
harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment for non-explosive sources--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 (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al. 2007, Ellison
et al. 2012). Based on what the available science indicates and the
practical need to use a threshold based on a factor that is both
predictable and measurable for most activities, NMFS uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS predicts that marine mammals are likely to
be behaviorally harassed in a manner we consider Level B harassment
when exposed to underwater anthropogenic noise above received levels of
120 dB re 1 micropascal ([micro]Pa) root mean square (rms) for
continuous (e.g., vibratory pile-driving) and above 160 dB re 1 [mu]Pa
(rms) for non-explosive impulsive (e.g., impact pile driving) or
intermittent (e.g., scientific sonar) sources.
CTJV's proposed activity includes the use of continuous (vibratory
pile driving/removal) and impulsive (impact pile driving; DTH hammer)
sources and, therefore, the 120 and 160 dB re 1 [mu]Pa (rms) are
applicable.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (NMFS 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 activity includes the use of impulsive (impact pile driving;
DTH drilling) and non-impulsive (vibratory pile driving) sources.
These thresholds are provided in the Table 5 below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS 2018 Technical Guidance, which may be accessed at
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 5--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; LE,LF,24h: 183 Cell 2: LE,LF,24h: 199 dB.
dB.
Mid-Frequency (MF) Cetaceans Cell 3: Lpk,flat: 230 dB; LE,MF,24h: 185 Cell 4: LE,MF,24h: 198 dB.
dB.
High-Frequency (HF) Cell 5: Lpk,flat: 202 dB; LE,HF,24h: 155 Cell 6: LE,HF,24h: 173 dB.
Cetaceans. dB.
Phocid Pinnipeds (PW) Cell 7: Lpk,flat: 218 dB; LE,PW,24h: 185 Cell 8: LE,PW,24h: 201 dB.
(Underwater). dB.
Otariid Pinnipeds (OW) Cell 9: Lpk,flat: 232 dB; LE,OW,24h: 203 Cell 10: LE,OW,24h: 219 dB.
(Underwater). 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 will feed into identifying the area ensonified above the
acoustic thresholds, which include 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.
Pile driving generates underwater noise that can potentially result in
disturbance to marine mammals in the project area. The maximum
(underwater) area ensonified is determined by the topography of the Bay
including shorelines to the west south and north as well as by hard
structures such as portal islands.
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; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven
pile, and
R2 = the distance from the driven pile of the initial
measurement
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log[range]). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting
[[Page 64862]]
in a reduction of 3 dB in sound level for each doubling of distance
from the source (10*log[range]). A practical spreading value of fifteen
is often used under conditions, such as the PTST project site where
water generally increases with depth as the receiver moves away from
pile driving locations, resulting in an expected propagation
environment that would lie between spherical and cylindrical spreading
loss conditions. Practical spreading loss is assumed here.
The intensity of pile driving sounds is greatly influenced by
factors such as the type of piles, hammers, and the physical
environment in which the activity takes place. In order to calculate
distances to the Level A harassment and Level B harassment thresholds
for the 36-inch steel piles proposed in this project, CTJV used
acoustic monitoring data from other locations as described in Caltrans
2015 for impact and vibratory driving. CTJV also conducted their own
sound source verification testing on 42-inch steel casings as described
below to determine source levels associated with DTH drilling. NMFS
used vibratory driving of 36-in steel pile source levels for vibratory
driving of 42-inch casings source levels. CTJV has proposed to employ
bubble curtains during impact driving of 36-inch steel piles and,
therefore, reduced the source level by 7 dB (a conservative estimate
based on several studies including Austin et al. 2016).
Source levels for drilling with a DTH hammer were field verified at
the PTST project site by JASCO Applied Sciences in July 2019 (Denes,
2019). Underwater sound levels were measured during drilling with a DTH
hammer at five pile locations--3 without bubble curtain attenuation and
2 with bubble curtain attenuation. The average SPL value at 10 m for
the DTH location without a bubble curtain was 180 dB re 1[mu]Pa, while
the average SEL and PK levels were 164 dB re 1[mu]Pa2[middot]s and 190
dB re 1[mu]Pa, respectively. These values were greater than DTH testing
done at another location in Alaska (Denes et al. 2016). The dominant
signal characteristic was found to be impulsive rather than continuous.
Southall et al. (2007) suggested that impulsive sounds can be
distinguished from non-impulsive sounds by comparing the SPL of a 0.035
s window that includes the pulse and with a 1 s window that may include
multiple pulses. If the SPL of the 0.035 s window is 3 dB or more
greater than the 1 s window, then the signal should be considered
impulsive. Denes (2019) observed that at the PTST site, the SPL of the
0.035 s pulse is 5 dB higher than the SPL of the 1 s sample, so the DTH
source is classified here as impulsive. Source levels associated with
DTH drilling of 42-inch steel casings were assumed to be the same as
recorded for installation of 36-in steel pipe by DTH.
CTJV utilized in-water measurements generated by the Greenbusch
Group (2018) from the WSDOT Seattle Pier 62 project (83 FR 39709) to
establish proxy sound source levels for vibratory installation and
removal of 14-inch timber piles. NMFS reviewed the report by the
Greenbusch Group (2018) and determined that the findings were derived
by pooling together all steel pile and timber pile at various distance
measurements data together. The data was not normalized to the standard
10 m distance. NMFS analyzed source measurements at different distances
for all 63 individual timber piles that were removed and normalized the
values to 10 m. The results showed that the median is 152 dB SPLrms.
This value was used as the source level for vibratory removal of 14-
inch timber piles. Source levels for impact driving of 12-in timber
piles were from the Ballena Bay Marina project in Alameda, CA as
described in Caltrans 2015. Sound source levels used to calculate take
are shown in Table 6.
Table 6--The Sound Source Levels (dB Peak, dB RMS, and dB sSEL) by Hammer Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated
Estimated peak Estimated single strike
Type of pile Hammer type noise level pressure level sound exposure Relevant piles at the Pile function
(dB peak) (dB RMS) level (dB PTST project
sSEL)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch Steel Pipe............... Impact \a\.......... 210 193 183 Plumb.................... Omega Trestle,
Temporary Dock,
Berm Wall West, and
Berm Wall East.
Impact with Bubble 203 186 176 Plumb.................... Berm Wall West, Berm
Curtain \b\. Wall East, and
Temporary Dock.
DTH--Impulsive \d\.. 190 180 164 Plumb.................... Omega Trestle, Berm
Wall West, and Berm
Wall East.
Vibratory \a\....... NA 170 170 Pipe Piles............... Mooring Piles and
Templates.
12-inch Timber Pile.............. Vibratory \c\....... NA 152 152 Plumb.................... Mooring Dolphins.
Impact \a\.......... 177 165 157 Plumb.................... Mooring Dolphins.
42-inch Steel Casing............. DTH--Impulsive \d\.. 190 180 164 Steel Casing............. Temporary Dock.
Vibratory \a\....... NA 170 170 Pipe Piles............... Temporary Dock.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: sSEL = Single Strike Exposure Level; dB = decibel; N/A = not applicable.
\a\ Caltrans 2015.
\b\ 7 dB reduction was assumed for use an encased bubble curtain (Austin et al. 2016).
\c\ Greenbusch Group 2018.
\d\ Denes et al. 2019.
CTJV used NMFS' Optional User Spreadsheet, available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance, to input project-specific parameters and
calculate the isopleths for the Level A harassment zones for impact and
vibratory pile driving. When the NMFS Technical Guidance (2016) was
published, in recognition of the fact that ensonified area/volume could
be more technically challenging to predict because of the duration
component in the new thresholds, we developed a User Spreadsheet that
includes tools to help predict a simple isopleth that can be used in
conjunction with marine mammal density or occurrence to help predict
takes. We note that because of some of the assumptions included in the
methods used for these tools, we anticipate that isopleths produced are
typically going to be overestimates of some degree, which may result in
some degree of overestimate of Level A harassment take. However, these
tools offer the best way to predict appropriate isopleths when more
sophisticated 3D modeling methods are not available, and NMFS continues
to develop ways to quantitatively refine these tools, and will
qualitatively address the output where appropriate. For stationary
source pile driving, the NMFS User Spreadsheet predicts the distance at
[[Page 64863]]
which, if a marine mammal remained at that distance the whole duration
of the activity, it would incur PTS.
Table 7 provides the sound source values and input used in the User
Spreadsheet to calculate harassment isopleths for each source type
while Table 8 shows distances to Level A harassment isopleths. Note
that the isopleths calculated using the proposed number of piles driven
per day is highly conservative. PTS is based on accumulated exposure
over time. Therefore, an individual animal would have to be within the
calculated PTS zones when all of the piles of a single type and driving
method are being actively installed throughout an entire day. The
marine mammals proposed for authorization are highly mobile. It is
unlikely that an animal would remain within the PTS zone during the
installation of, for example, 10 piles over an 8-hour period. NMFS
opted to reduce the number of piles driven per day by approximately 50
percent in order to derive more realistic PTS isopleths. In cases where
the number of proposed piles per day was an odd number, NMFS used the
next largest whole number that was greater than 50 percent. These are
shown in Table 7 in the row with the heading ``Piles/day to calculate
PTS.'' Table 8 contains calculated distances to PTS isopleths and Table
9 depicts distances to Level B harassment isopleths.
Table 7--User Spreadsheet Input Parameters Used for Calculating Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
12-in timber 36-in steel 42-in steel casing
--------------------------------------------------------------------------------------------------------
Model parameter Impact--with
Vibratory Impact Vibratory Impact bubble DTH Vibratory DTH DTH--simult.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used........................... * A.1 ** E.1 A.1 E.1 E.1 E.1 A.1 E.1 E.1
Weighting Factor (kHz)......................... 2.5 2 2.5 2.0 2.0 2.0 2.5 2.0 2.0
RMS (dB)....................................... 152 165 170 193 186 180 170 180 180
Peak/SEL (dB).................................. na 177/157 na 210/183 203/176 190/164 na 190/164 190/164
Proposed Piles/day............................. 10 10 10 7 10 3 10 3 6
Piles/day to calculate PTS..................... 5 5 5 4 5 2 5 2 3
Duration to drive pile (minutes)............... 30 na 12 na na na 12 na na
Propagation.................................... 15 15 15 15 15 15 15 15 15
Distance from source (meters).................. 10 10 10 10 10 10 10 10 10
Strikes per pile............................... na 1000 na 1000 1000 25200 na 25200 50400
--------------------------------------------------------------------------------------------------------------------------------------------------------
* A.1) Vibratory Pile driving.
** E.1) Impact Pile Driving.
Table 8--Radial Distance to PTS Isopleths (meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Scenario Low-frequency Mid-frequency High-frequency Phocid Pile location
------------------------------------------------------------ cetaceans cetaceans cetaceans pinnipeds ----------------------------
----------------------------------------------------------------
Driving type Pile type Distance from Distance from Distance from Distance from
islands 1 & 2 islands 1 & 2 islands 1 & 2 islands 1 & 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact............................. 12-in. Timber......... 54 1.9 65 2 Mooring Dolphins.
36-in. Steel.......... 2,516 90 2,997 1,347 Omega Trestle, Temporary
Dock, Berm Wall West, and
Berm Wall East.
Impact with Bubble Curtain......... 36-in. Steel.......... 997 36 1,188 534 Berm Wall West, Berm Wall
East, and Temporary Dock.
DTH--Impulsive..................... 42-in. Steel.......... 737 26 878 395 Casing for Temporary Dock.
36-in. Steel.......... 737 26 878 395 Omega Trestle, Temporary
Dock, Berm Wall West, and
Berm Wall East.
DTH Simultaneous................... 42-in. Steel.......... 1,534 55 1,827 821 Omega Trestle, Temporary
Dock, Berm Wall West, and
Berm Wall East.
DTH & Impact Hammer with bubble 36-and 42-in. Steel *. 1,734 62 2,066 929
curtain: Simultaneous at the same
island.
DTH at PI 1 and Impact with Bubble 36-and 42-in. Steel... 737 (Island 1) 26 (Island 1) 878 (Island 1) 395 (Island 1)
Curtain Hammer at PI 2. 997 (Island 2) 36 (Island 2) 1,188 (Island 534 (Island 2)
2)
Continuous (Vibratory)............. 12-in. Timber......... 3 0.3 5 2 Mooring Dolphins.
36-in. Steel.......... 27 2 40 17 Mooring Piles and
Templates.
42-in. Steel.......... * 27 * 2 * 40 * 17 Casing for Temporary Dock.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Activity will not occur on Portal Island 2.
[[Page 64864]]
Table 9--Radial Distance (meters) to Level B Harassment Monitoring Isopleths
----------------------------------------------------------------------------------------------------------------
Distance from
Driving method Pile type island 1 & 2 Pile location
----------------------------------------------------------------------------------------------------------------
Impact.................................. 12-in. Timber............. 22 Mooring Dolphins.
36-in. Steel.............. 1,555 Omega Trestle, Temporary
Dock, Berm Wall West, and
Berm Wall East.
Impact with Bubble Curtain.............. 36-in. Steel.............. 541 Berm Wall West, Berm Wall
East, and Temporary Dock.
DTH--Impulsive.......................... 42-in. Steel.............. * 215 Casing for Temporary Dock.
36-in. Steel.............. 215 Omega Trestle, Temporary
Dock, Berm Wall West, and
Berm Wall East.
Continuous (Vibratory).................. 12-in. mooring............ 1,354 Mooring Dolphins.
36-in. Steel.............. 21,544 Mooring Piles and
Templates.
42-in. Steel.............. * 21,544 Casing for Temporary Dock.
----------------------------------------------------------------------------------------------------------------
* Activity will not occur on Portal Island 2.
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals and describe how it is
brought together with the information above to produce a quantitative
take estimate. When available, peer-reviewed scientific publications
were used to estimate marine mammal abundance in the project area. In
some cases population estimates, densities, and other quantitative
information are lacking. Local observational data and estimated group
size were utilized where applicable.
Humpback Whale
Humpback whales are relatively rare in the Chesapeake Bay and
density data for this species within the project vicinity were not
available nor able to be calculated. Populations in the mid-Atlantic
have been estimated for humpback whales off the coast of New Jersey
with a density of 0.000130 per square kilometer (Whitt et al. 2015).
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 ranged from a high of 0.107/100 km\2\
in March to 0.00010/100 km\2\ in August. Furthermore, CTJV conducted
marine mammal monitoring during SSV testing for 5 days in July 2019.
During that time there were no sightings or takes of humpback whales.
Because humpback whale occurrence is low as demonstrated above,
CTJV and NMFS estimated that there will be a single humpback sighting
every two months for the duration of in-water pile driving activities.
Using an average group size of 2 animals, pile driving activities over
a 10-month period would result in 10 takes of humpback whale by Level B
harassment. No takes by Level A harassment are expected or proposed.
Bottlenose Dolphin
Expected bottlenose dolphin take 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). Three years of dolphin survey data were collected from either
in-shore or open ocean transects. In-shore transects occurred off the
coast of Virginia Beach in the Atlantic Ocean as well as inside the Bay
to the southwest of the proposed project area. The previously issued
IHA (83 FR 36522; July 30, 2018) used the same seasonal dolphin
densities provided by Engelhaupt et al. (2016) to calculate take.
CTJV used data from Engelhaupt et al. (2016) but employed a
different methodology to estimate take for this IHA. Dolphin sightings
are not uniformly distributed along the survey area. There were more
sightings along the Atlantic coastal ocean and fewer along the
shoreline within the Bay. It is likely that bottlenose dolphins do not
use the habitat uniformly, but rather selectively based on
heterogeneity in available habitat, dietary items and protection with
some individuals preferring ocean and others estuary (Ballance, 1992;
Gannon and Waples 2004). Although dolphins 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 in the Bay near the
project area. A spatially refined approach was employed by plotting
dolphin sightings within 12 km of the project location and then
determining densities following methodology outlined in Engelhaupt et
al. (2016) and Miller et al. (2019) using the package DISTANCE in R
statistical software. The distance of 12 km was selected for estimating
dolphin densities because uncertainty increases in extrapolating those
data out further from the geographical location of the survey.
Additionally, most of the sound generated by the proposed project will
be directed into the Bay where dolphin densities are less compared to
coastal ocean regions. Therefore, a 12 km radius should provide more
accurate density estimates near the proposed project area by excluding
higher density data from the coastal ocean areas.
Transect distance and areas were determined by using Image J
software (NIH Freeware) to trace individual transects within the
calculated Level B harassment zones. The entire length of the transects
was also calculated using Image J to determine the viability of this
approach where the average transect zig-zag from Image J was 3.6 km
compared to the methods in the report of a 3.7 km transect. Dolphin
sightings were truncated at 0.32 km from the transect line based on the
probability of accurate abundance estimations following the approach
from Engelhaupt et al. (2016). Density estimates were stratified based
on seasons (as defined by Engelhaupt et al. 2016) where there would be
sufficient data to run the model, as monthly density estimates did not
have enough data points. Seasonal densities are below in Table 10 and
Level B harassment zone areas are shown in Table 11.
Table 10--Bottlenose Dolphin Densities (Individual/km\2\) From Inshore
Areas of Virginia
------------------------------------------------------------------------
Density within 12
Season km of project
area
------------------------------------------------------------------------
Spring............................................... 0.6
Summer............................................... 0.62
Fall................................................. 1.17
Winter............................................... 0.26
------------------------------------------------------------------------
[[Page 64865]]
Table 11--In-Water Area (km\2\) Used for Calculating Dolphin Takes per Construction Components per Hammer Type
----------------------------------------------------------------------------------------------------------------
Impact with Vibratory Impact + DTH DTH + DTH
Construction component Impact hammer bubble curtain hammer hammers hammers
----------------------------------------------------------------------------------------------------------------
Mooring Cluster................. 0.003 0.003 4.16 .............. ..............
Temporary Dock.................. 5.55 0.63 830 .............. 0.25
Omega Trestle and West O-pile 8.55 8.55 830 1.72 0.49
wall...........................
East O-Pile Walls............... .............. .............. .............. 1.43 ..............
----------------------------------------------------------------------------------------------------------------
Densities from Table 10 and harassment zone areas from Table 11
were used to calculate the monthly takes based on the number of pile
driving days. The number of dolphin takes per construction component
per pile driving method was then summed for each month (Table 12). NMFS
proposes to authorize 10,109 incidents of take for bottlenose dolphin
by Level B harassment as shown in Table 12 and has split out the three
dolphin stocks as shown in Table 13. There is insufficient information
to apportion the takes precisely to the three stocks present in the
area. Given that most of the NNCES stock are found in the Pamlico Sound
estuarine system, NMFS will assume that no more than 200 of the
proposed takes will be from this stock. A subset of these 200 takes
would likely be comprised of Bay resident dolphins, although the number
is unknown. Since members of the northern migratory coastal and
southern migratory coastal stocks are thought to occur in or near the
Bay in greater numbers, we will conservatively assume that no more than
half of the remaining animals (9,909) will accrue to either of these
stocks.
During 5 days of SSV testing conducted by CTJV in July 2019,
dolphins were recorded every day with a minimum daily sighting rate of
8 (July 22, 2019 and maximum daily rate of 40 animals (July 23, 2019).
There were 116 total sightings of which 50 were recorded as takes by
Level B harassment. For comparative purposes, the average daily dolphin
take rate estimated for the proposed IHA is 54 animals while the
maximum sightings per day was 40 animals as noted above. Given this
information, NMFS is confident that the proposed dolphin take estimate
is reasonable, if somewhat conservative.
Table 12--Estimated Bottlenose Dolphin Take by Month and Driving Activity
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Month November December January February March April May June July August September October
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dolphin Density (n/km2)....................... 1.17 0.26 0.26 0.26 0.6 0.6 0.6 0.62 0.62 0.62 1.17 1.17
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mooring Cluster
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory--Timber Piles....................... 7 2 0 0 0 0 0 0 0 0 0 0
Impact--Timber Piles.......................... 3 1 0 0 0 0 0 0 0 0 0 0
Dolphin Takes................................. 34 2 0 0 0 0 0 0 0 0 0 0 36
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Dock
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Impact--Steel Pile............................ 0 1 1 1 1 1 1 0 0 0 0 0
Impact with Bubble Curtain--Steel Pile........ 0 2 2 2 2 2 2 0 0 0 0 0
Vibratory--Steel Pile......................... 0 4 4 4 4 4 4 0 0 0 0 0
Two DTH--Steel Pile........................... 0 3 3 3 3 3 3 0 0 0 0 0
Dolphin Takes................................. 0 865 649 649 1,499 1,499 1,499 0 0 0 0 0 6,660
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Omega Trestle/West O-pile Walls/Mooring Piles & Templates
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Impact--Steel Pile............................ 2 2 2 2 4 3 2 0 0 0 0 0
Vibratory--Steel Pile......................... 1 1 0 0 0 0 1 1 1 1 0 0
Two DTH--Steel Pile........................... 2 2 2 2 6 4 4 0 0 0 0 0
DTH+ Impact--Steel Pile....................... 3 3 3 3 8 6 4 0 0 0 0 0
Dolphin Takes................................. 998 222 6 6 31 23 514 515 515 515 0 0 3,343
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Omega Trestle/East O-Pile Walls
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Impact--Steel Pile............................ 0 2 2 2 2 4 2 2 2 2 0 0
DTH+ Impact--Steel Pile....................... 0 1 1 1 1 2 1 1 1 1 0 0
Two DTH--Steel Pile........................... 0 1 1 1 1 2 1 1 1 1 0 0
Dolphin Takes................................. 0 4 4 4 8 16 8 9 9 9 0 0 70
Total No. of Pile Driving Days per Month...... 18 25 21 21 32 31 25 5 5 5 0 0
-------------------------------------------------------------------------------------------------------------------------------------------------
Total Level B harassment Takes............ .......... .......... ......... ......... ......... ......... ......... ......... ......... ......... .......... ......... 10,109
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor Porpoise
Given that harbor porpoises are uncommon in the project area, this
exposure analysis assumes that there is a porpoise sighting once during
every two months of operations which would equate to five sightings
over ten months. Assuming an average group size of two (Hansen et al.
2018; Elliser et al. 2018) over 10 months of in-water work results in a
total of 10 estimated takes of porpoises. Harbor porpoises are members
of the high-frequency hearing group which have Level A harassment
isopleths as large as 2,997 m during impact installation of four piles
per day. Given the relatively large Level A harassment zones during
impact driving, NMFS assumed in the previous IHA (83 FR 36522; July 30,
2018) that 40 percent of estimated porpoises takes would be by Level A
harassment and authorized 4 takes of porpoises by Level A and 6 takes
by Level B harassment. CTJV conducted marine mammal monitoring during
SSV testing at the
[[Page 64866]]
project location for 5 days in July 2019. During that time there were
no sightings or takes of porpoises. However, NMFS is conservatively
proposing to authorize the same number of porpoise takes for Level A
and Level B harassment for this IHA.
Harbor Seal
The number of harbor seals expected to be present in the PTST
project area was estimated using survey data for in-water and hauled
out seals collected by the United States Navy at the portal islands
from November 2014 through April 2018 (Rees et al., 2016; Jones et al.
2018). The survey data revealed a daily maximum of 45 animals during
this period which occurred in January, 2018. The maximum number of
animals observed per day (45) was multiplied by the total number of
proposed driving days between November and May (173) since (seals are
not present in the area from June through October). Based on this
calculation NMFS proposes to authorize 7,785 incidental takes of harbor
seal. Note that the CTJV monitoring report did not record any seal
observations over 5 days of SSV testing, but this would be expected as
seals are not present during July.
The largest Level A harassment isopleth for phocid species is
approximately 1,347 meters which would occur during impact driving of
36-inch steel piles. The smallest Level A harassment isopleths are 2 m
and would occur during impact and vibratory driving of 12-inch timber
piles. NMFS has prescribed a shutdown zone for harbor seals of 15
meters as a mitigation measure since seals are common in the project
area and are known to approach the shoreline. A larger shutdown zone
would likely result in multiple shutdowns and impede the project
schedule. From the previously issued IHA, NMFS assumed that 40 percent
of the exposed seals will occur within the Level A harassment zone
specified for a given scenario and the remaining affected seals would
result in Level B harassment takes. Therefore, NMFS proposes to
authorize 3,114 takes by Level A harassment and 4,671 takes by Level B
harassment.
Gray Seal
The number of gray seals expected to be present at the PTST project
area was estimated using survey data collected by the U.S. Navy at the
portal islands from 2014 through 2018 (Rees et al. 2016; Jones et al.
2018). One seal was observed in February of 2015 and one seal was
recorded in February of 2016 while no seals were observed at any time
during 2017 or 2018. Since seals are anticipated to occur only during
the month of February at a rate of 1 animal per day for the anticipated
21 in-water work days during that month, NMFS proposes to authorized 21
incidental takes of gray seal. The Level A isopleths for gray seals are
identical to those for harbor seals. With a shutdown zone of 15 meters,
previously, NMFS previously estimated 40 of the total take (not 40
percent of the affected species or stock) would occur in the Level A
harassment zone specified for a given scenario. Therefore, NMFS
proposes to authorize 8 takes by Level A harassment and 13 takes by
Level B harassment.
Table 13 shows that estimated percentage of stock proposed for take
by both Level A and Level B harassment.
Table 13--Estimated Take by Level A and Level B Harassment
----------------------------------------------------------------------------------------------------------------
Species Stock Level A takes Level B takes
----------------------------------------------------------------------------------------------------------------
Humpback whale................................ Gulf of Maine................... .............. 10
Harbor porpoise............................... Gulf of Maine/Bay of Fundy...... 4 6
Bottlenose dolphin............................ WNA Coastal, Northern Migratory. .............. 4,955
WNA Coastal, Southern Migratory. .............. 4,954
NNCES........................... .............. 200
Harbor seal................................... Western North Atlantic.......... 3,114 4,671
Gray seal..................................... Western North Atlantic.......... 8 13
----------------------------------------------------------------------------------------------------------------
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 such
activity, and other means of effecting the least practicable impact on
such species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such 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 such
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, we
carefully consider 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, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
In addition to the measures described later in this section, CTJV
will employ the following standard mitigation measures:
Conduct briefings between construction supervisors and
crews and the marine mammal monitoring team prior to the start of all
pile driving activity, and when new personnel join the work, to explain
responsibilities, communication procedures, marine mammal monitoring
protocol, and operational procedures;
For in-water heavy machinery work other than pile driving
(e.g., standard barges, etc.), if a marine mammal comes
[[Page 64867]]
within 10 m, operations shall cease and vessels shall reduce speed to
the minimum level required to maintain steerage and safe working
conditions. This type of work could include the following activities:
(1) Movement of the barge to the pile location; or (2) positioning of
the pile on the substrate via a crane (i.e., stabbing the pile);
Work may only occur during daylight hours, when visual
monitoring of marine mammals can be conducted;
For those marine mammals for which Level B harassment take
has not been requested, in-water pile driving will shut down
immediately if such species are observed within or entering the
monitoring zone (i.e., Level B harassment zone); and
If take reaches the authorized limit for an authorized
species, pile installation will be stopped as these species approach
the Level B harassment zone to avoid additional take.
The following measures would apply to CTJV's mitigation
requirements:
Establishment of Shutdown Zone--For all pile driving and drilling
activities, CTJV would establish a shutdown zone. The purpose of a
shutdown zone is generally to define an area within which shutdown of
activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). These shutdown
zones would be used to prevent incidental Level A harassment from
impact pile driving for bottlenose dolphins and humpback whales.
Shutdown zones for species proposed for authorization are as follows:
100 meters for harbor porpoise and bottlenose dolphin.
15 meters for harbor seal and gray seal.
For humpback whale, shutdown distances are shown in Table
14 under low-frequency cetaceans and are dependent on activity type.
Establishment of Monitoring Zones for Level A and Level B
Harassment--CTJV would establish monitoring zones based on calculated
Level A harassment isopleths associated with specific pile driving
activities and scenarios. These are areas beyond the established
shutdown zone in which animals could be exposed to sound levels that
could result in Level A harassment in the form of PTS. CTJV would also
establish and monitor Level B harassment zones which are areas where
SPLs are equal to or exceed the 160 dB rms threshold for impact driving
and DTH drilling and 120 dB rms threshold during vibratory driving.
Monitoring zones provide utility for observing by establishing
monitoring protocols for areas adjacent to the shutdown zones. The
monitoring zones enable observers to be aware of and communicate the
presence of marine mammals in the project area outside the shutdown
zone and thus prepare for a potential cease of activity should the
animal enter the shutdown zone. The proposed Level A and Level B
harassment monitoring zones are described in Table 14. Since some of
the Level B harassment monitoring zones cannot be effectively observed
in their entirety, Level B harassment exposures will be recorded and
extrapolated based upon the number of observed take and the percentage
of the Level B harassment zone that was not visible.
Table 14--Level A and Level B Harassment Monitoring Zones During Project Activities (meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Scenario Level A harassment zones Level B
----------------------------------------------------------------------------------------------------------------------------------------- monitoring
Low-frequency Mid-frequency High- Phocid zones
cetaceans cetaceans frequency pinnipeds ---------------
Driving type Pile type -------------------------------- cetaceans ----------------
---------------- Island 1 & 2
Island 1 & 2 Island 1 & 2 * Island 1 & 2 Island 1 & 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact.................................... 12-in. Timber............... 55 .............. .............. .............. 25
36-in. Steel................ 2,520 .............. 3,000 1,350 1,585
Impact with Bubble Curtain................ 36-in. Steel................ 1,000 .............. 1,190 540 545
DTH--Impulsive............................ 42-in. Steel................ 740 .............. 880 395 220
DTH Simultaneous at same island........... 42-in. Steel................ 1,535 .............. 1,830 825 220
DTH & Impact Hammer with bubble curtain: 36- and 42-in. Steel........ 1,735 .............. 2,070 930 545
Simultaneous at the same island.
DTH at PI 1. And Impact with Bubble 36- and 42-in. Steel........ 740 .............. 880 395 220 from PI 1
Curtain Hammer at PI 2. 545 from PI 2
Continuous (Vibratory).................... 12-in. Timber............... .............. .............. .............. .............. 1,360
36-in. Steel................ 30 .............. .............. 20 21,545
42-in.** Steel.............. 30 .............. .............. 20 21,545
--------------------------------------------------------------------------------------------------------------------------------------------------------
* indicates that shutdown zone is larger than calculated harassment zone.
** Activity only proposed at Portal Island 1 as part of project pile driving plan.
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 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 begins. Soft start would be implemented at the
start of each day's impact pile driving and at any time following
cessation of impact pile driving for a period of 30 minutes or longer.
Soft start is not required during vibratory or DTH pile driving
activities.
Use of bubble curtains--Use of air bubble curtain system would be
implemented by CTJV during impact driving of 36-in steel piles except
in water less than 10 ft in depth. The use of this sound attenuation
device will reduce SPLs and the size of the zones of influence for
Level A harassment and Level B harassment. Bubble curtains would meet
the following requirements:
The bubble curtain must distribute air bubbles around 100
percent of the piling perimeter for the full depth of the water column.
The lowest bubble ring shall be in contact with the
mudline and/or rock bottom for the full circumference of the ring, and
the weights attached to the bottom ring shall ensure 100 percent
mudline and/or rock bottom contact. No parts of the ring or other
objects shall
[[Page 64868]]
prevent full mudline and/or rock bottom contact.
The bubble curtain shall be operated such that there is
proper (equal) balancing of air flow to all bubblers.
The applicant shall require that construction contractors
train personnel in the proper balancing of air flow to the bubblers and
corrections to the attenuation device to meet the performance
standards. This shall occur prior to the initiation of pile driving
activities.
Pre-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, protected species observers (PSOs) will
observe the shutdown and monitoring zones for a period of 30 minutes.
The shutdown zone will be cleared when a marine mammal has not been
observed within the zone for that 30-minute period. If a marine mammal
is observed within the shutdown zone, a soft-start cannot proceed until
the animal has left the zone or has not been observed for 15 minutes.
If the Level B harassment zone has been observed for 30 minutes and
non-permitted species are not present within the zone, soft start
procedures can commence and work can continue even if visibility
becomes impaired within the Level B harassment monitoring zone. When a
marine mammal permitted for take by Level B harassment is present in
the Level B harassment zone, activities may begin and Level B
harassment take will be recorded. If work ceases for more than 30
minutes, the pre-activity monitoring of both the Level B harassment and
shutdown zone will commence again.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means 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 in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density).
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas).
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors.
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks.
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat).
Mitigation and monitoring effectiveness.
Marine Mammal Visual Monitoring
Monitoring shall be conducted by NMFS-approved observers. Trained
observers shall be placed from the best vantage point(s) practicable to
monitor for marine mammals and implement shutdown or delay procedures
when applicable through communication with the equipment operator.
Observer training must be provided prior to project start, and shall
include instruction on species identification (sufficient to
distinguish the species in the project area), description and
categorization of observed behaviors and interpretation of behaviors
that may be construed as being reactions to the specified activity,
proper completion of data forms, and other basic components of
biological monitoring, including tracking of observed animals or groups
of animals such that repeat sound exposures may be attributed to
individuals (to the extent possible).
Monitoring would be conducted 30 minutes before, during, and 30
minutes after pile driving activities. In addition, observers shall
record all incidents of marine mammal occurrence, regardless of
distance from activity, and shall document any behavioral reactions in
concert with distance from piles being driven. Pile driving activities
include the time to install 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.
CTJV would be required to station PSOs at locations offering the
best available views of the monitoring zones. At least one PSO must be
located in close proximity to each pile driving rig during active
operation of single or multiple, concurrent driving devices. A minimum
of one additional PSO is required at each active driving rig if the
Level B harassment zone and shutdown zones cannot reasonably be
observed by one PSO.
PSOs would scan the waters using binoculars, and/or spotting
scopes, and would use a handheld GPS or range-finder device to verify
the distance to each sighting from the project site. All PSOs would be
trained in marine mammal identification and behaviors and are required
to have no other project-related tasks while conducting monitoring. In
addition, monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable to monitor for
marine mammals and implement shutdown/delay procedures when applicable
by calling for the shutdown to the hammer operator. CTJV would adhere
to the following PSO qualifications:
(i) Independent observers (i.e., not construction personnel) are
required.
(ii) At least one observer must have prior experience working as an
observer.
(iii) Other observers may substitute education (degree in
biological science or related field) or training for experience.
(iv) Where a team of three or more observers are required, one
observer shall be designated as lead observer or monitoring
coordinator. The lead observer must have prior experience working as an
observer.
(v) CTJV shall submit observer CVs for approval by NMFS.
Additional standard observer qualifications include:
Ability to conduct field observations and collect data
according to assigned protocols;
Experience or training in the field identification of
marine mammals,
[[Page 64869]]
including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates and times when in-water construction
activities were suspended to avoid potential incidental injury from
construction sound of marine mammals observed within a defined shutdown
zone; and marine mammal behavior; and
Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Observers will be required to use approved data forms. Among other
pieces of information, CTJV will record detailed information about any
implementation of shutdowns, including the distance of animals to the
pile and description of specific actions that ensued and resulting
behavior of the animal, if any. In addition, CTJV will attempt to
distinguish between the number of individual animals taken and the
number of incidences of take. We require that, at a minimum, the
following information be collected on the sighting forms:
Date and time that monitored activity begins or ends;
Construction activities occurring during each observation
period;
Weather parameters (e.g., percent cover, visibility);
Water conditions (e.g., sea state, tide state);
Species, numbers, and, if possible, sex and age class of
marine mammals;
Description of any observable marine mammal behavior
patterns, including bearing and direction of travel and distance from
pile driving activity, and if possible, the correlation to SPLs;
Distance from pile driving activities to marine mammals
and distance from the marine mammals to the observation point;
Description of implementation of mitigation measures
(e.g., shutdown or delay);
Locations of all marine mammal observations; and
Other human activity in the area.
Reporting
A draft report would be submitted to NMFS within 90 days of the
completion of marine mammal monitoring, or 60 days prior to the
requested date of issuance of any future IHA for projects at the same
location, whichever comes first. The report will include marine mammal
observations pre-activity, during-activity, and post-activity during
pile driving days (and associated PSO data sheets), and will also
provide descriptions of any behavioral responses to construction
activities by marine mammals and a complete description of all
mitigation shutdowns and the results of those actions and an
extrapolated total take estimate based on the number of marine mammals
observed during the course of construction. A final report must be
submitted within 30 days following resolution of comments on the draft
report.
Reporting Injured or Dead Marine Mammals
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, CTJV shall report the
incident to the Office of Protected Resources (OPR), NMFS and to the
Greater Atlantic Region New England/Mid-Atlantic Regional Stranding
Coordinator as soon as feasible. The report must include the following
information:
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive;
If available, photographs or video footage of the
animal(s); and
General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), 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's 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 environmental 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).
Pile driving activities associated with the proposed PTST project,
as outlined previously, have the potential to disturb or displace
marine mammals. The specified activities may result in take, in the
form of Level B harassment (behavioral disturbance) or Level A
harassment (auditory injury), incidental to underwater sounds generated
from pile driving. Potential takes could occur if individuals are
present in the ensonified zone when pile driving occurs. Level A
harassment is only anticipated for harbor porpoises, harbor seals, and
gray seals.
No serious injury or mortality is anticipated given the nature of
the activities and measures designed to minimize the possibility of
injury to marine mammals. The potential for these outcomes is minimized
through the construction method and the implementation of the planned
mitigation measures. Specifically, vibratory driving, impact driving,
and drilling with DTH hammers will be the primary methods of
installation and pile removal will occur with a vibratory hammer.
Impact pile driving produces short, sharp pulses with higher peak
levels and much sharper rise time to reach those peaks. When impact
pile driving is used, implementation of bubble curtains, soft start and
shutdown zones significantly reduces any possibility of injury. Given
sufficient notice through use of soft starts (for impact driving),
marine mammals are expected to move away from a sound source that is
annoying prior to it becoming potentially injurious.
CTJV will use qualified PSOs stationed strategically to increase
detectability of marine mammals, enabling a high rate of success in
implementation of shutdowns to avoid injury for most species. PSOs will
be stationed on a specific Portal Island
[[Page 64870]]
whenever pile driving operations are underway at that location. More
than one PSO may be stationed on an island in order to provide a
relatively clear view of the shutdown zone and monitoring zones. These
factors will limit exposure of animals to noise levels that could
result in injury.
CTJV's proposed pile driving activities are highly localized. Only
a relatively small portion of the Chesapeake Bay may be affected.
Localized noise exposures produced by project activities may cause
short-term behavioral modifications in affected cetaceans and pinnipeds
Moreover, the proposed mitigation and monitoring measures are expected
to further reduce the likelihood of injury as well as reduce behavioral
disturbances.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, will likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring) (e.g., Thorson and Reyff
2006). Individual animals, even if taken multiple times, will most
likely move away from the sound source and be temporarily displaced
from the areas of pile driving, although even this reaction has been
observed primarily only in association with impact pile driving. The
pile driving activities analyzed here are similar to, or less impactful
than, numerous other construction activities conducted along both
Atlantic and Pacific coasts, which have taken place with no known long-
term adverse consequences from behavioral harassment. Furthermore, many
projects similar to this one are also believed to result in multiple
takes of individual animals without any documented long-term adverse
effects. Level B harassment will be minimized through use of mitigation
measures described herein and, if sound produced by project activities
is sufficiently disturbing, animals are likely to simply avoid the area
while the activity is occurring.
In addition to the expected effects resulting from authorized Level
B harassment, we anticipate that small numbers of harbor porpoises,
harbor seals and gray seals may sustain some limited Level A harassment
in the form of auditory injury. However, animals 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's threshold would increase
by a few dBs, which is not likely to meaningfully affect its ability to
forage and communicate with conspecifics. 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 sufficient notice through use of
soft start.
The project is not expected to have significant adverse effects on
marine mammal habitat. No important feeding and/or reproductive areas
for marine mammals are known to be near the project area. Project
activities would not permanently modify existing marine mammal habitat.
The activities may cause some fish to leave the area of disturbance,
thus temporarily impacting marine mammal foraging opportunities in a
limited portion of the foraging range. However, because of the
relatively small area of the habitat that may be affected, the impacts
to marine mammal habitat are not expected to cause significant or long-
term negative consequences.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
No mortality is anticipated or authorized;
Limited Level A harassment exposures (harbor porpoises,
harbor seals, and gray seals) are anticipated to result only in slight
PTS, within the lower frequencies associated with pile driving;
The anticipated incidents of Level B harassment consist
of, at worst, temporary modifications in behavior that would not result
in fitness impacts to individuals;
The specified activity and associated ensonifed areas are
very small relative to the overall habitat ranges of all species and
does not include habitat areas of special significance (BIAs or ESA-
designated critical habitat); and
The presumed efficacy of the proposed mitigation measures
in reducing the effects of the specified activity.
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 above, only small numbers of incidental take 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. Additionally, other qualitative
factors may be considered in the analysis, such as the temporal or
spatial scale of the activities.
The proposed take of marine mammal stocks comprises less than 10.2
percent of the Western North Atlantic harbor seal stock abundance, and
less than one percent of the other stocks, with the exception of
bottlenose dolphin stocks. There are three bottlenose dolphin stocks
that could occur in the project area. Therefore, the estimated 10,109
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 200 takes from the NNCES stock, 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 Bay. The majority of
both stocks are likely to be found widely dispersed across their
respective habitat
[[Page 64871]]
ranges and unlikely to be concentrated in or near the Chesapeake Bay.
Furthermore, the Chesapeake Bay and nearby offshore waters
represent the boundaries of the ranges of each of the two coastal
stocks during migration. The northern migratory coastal stock is found
during warm water months from coastal Virginia, including the
Chesapeake Bay and Long Island, New York. The stock migrates south in
late summer and fall. During cold water months dolphins may be found in
coastal waters from Cape Lookout, North Carolina, to the North
Carolina/Virginia. During January-March, the southern migratory coastal
stock appears to move as far south as northern Florida. From April to
June, the stock moves back north to North Carolina. During the warm
water months of July-August, the stock is presumed to occupy coastal
waters north of Cape Lookout, North Carolina, to Assateague, Virginia,
including the Chesapeake Bay. There is likely some overlap between the
northern and southern migratory stocks during spring and fall
migrations, but the extent of overlap is unknown.
The Bay and waters offshore of the mouth are located on the
periphery of the migratory ranges of both coastal stocks (although
during different seasons). Additionally, each of the migratory coastal
stocks are likely to be located in the vicinity of the Bay for
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 (~two 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. However, recent evidence suggests that there is like a
small resident community of NNCES dolphins that inhabits the Chesapeake
Bay year-round (Patterson, Pers. Comm).
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, pers. comm.).
Multiple sightings of the same individual would considerably reduce the
number of individual animals that are taken by harassment. Furthermore,
the existence of a resident dolphin population in the Bay would
increase the percentage of dolphin takes that are actually re-sightings
of the same individuals.
In summary and as described above, the following factors primarily
support our preliminary determination regarding the incidental take of
small numbers of a species or stock:
The take of marine mammal stocks proposed for
authorization comprises less than 9 percent of any stock abundance
(with the exception of bottlenose dolphin stocks);
Potential bottlenose dolphin takes in the project area are
likely to be allocated among three distinct stocks;
Bottlenose dolphin stocks in the project area have
extensive ranges and it would be unlikely to find a high percentage of
any one stock concentrated in a relatively small area such as the
project area or the Bay;
The Bay represents the migratory boundary for each of the
specified dolphin stocks and it would be unlikely to find a high
percentage of any stock concentrated at such boundaries; and
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 will be taken relative to the population size
of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act (ESA)
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.
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 the CTJV for conducting pile driving activities as part
of the PTST project for a period of one year from the date of issuance,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the proposed IHA can be found
at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
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 PTST
project. We also request at this time 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.
On a case-by-case basis, NMFS may issue a one-year IHA renewal with
an additional 15 days for public comments when (1) another year of
identical or nearly identical activities as described in the Specified
Activities section of this notice is planned or (2) the activities as
described in the Specified Activities section of this notice would
[[Page 64872]]
not be completed by the time the IHA expires and a Renewal would allow
for completion of the activities beyond that described in the Dates and
Duration section of this notice, provided all of the following
conditions are met:
A request for renewal is received no later than 60 days
prior to expiration of the current IHA.
The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested Renewal 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
because only a subset of the initially analyzed activities remain to be
completed under the Renewal).
(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: November 19, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2019-25471 Filed 11-22-19; 8:45 am]
BILLING CODE 3510-22-P