[Federal Register Volume 84, Number 83 (Tuesday, April 30, 2019)]
[Notices]
[Pages 18346-18381]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-08666]
[[Page 18345]]
Vol. 84
Tuesday,
No. 83
April 30, 2019
Part II
Department of Commerce
-----------------------------------------------------------------------
National Oceanic and Atmospheric Administration
-----------------------------------------------------------------------
Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to Construction of the Vineyard Wind Offshore
Wind Project; Notice
Federal Register / Vol. 84 , No. 83 / Tuesday, April 30, 2019 /
Notices
[[Page 18346]]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XG882
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Construction of the Vineyard Wind
Offshore Wind Project
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.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from Vineyard Wind, LLC to take
marine mammals incidental to construction of a commercial wind energy
project offshore Massachusetts. 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 May 30,
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
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: Jordan Carduner, 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: 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 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. Accordingly, NMFS plans to adopt the Bureau
of Ocean Energy Management's (BOEM) Environmental Impact Statement
(EIS), provided our independent evaluation of the document finds that
it includes adequate information analyzing the effects on the human
environment of issuing the IHA. NMFS is a cooperating agency on BOEM's
EIS. BOEM's draft EIS was made available for public comment from
December 7, 2018 to February 22, 2019 and is available at:
www.boem.gov/Vineyard-Wind.
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 September 7, 2018, NMFS received a request from Vineyard Wind
LLC (Vineyard Wind) for an IHA to take marine mammals incidental to
construction of an offshore wind energy project south of Massachusetts.
Vineyard Wind submitted revised versions of the application on October
11, 2018 and on January 28, 2019. The application was deemed adequate
and complete on February 15, 2018. Vineyard Wind's request is for take
of 15 species of marine mammals by harassment. Neither Vineyard Wind
nor NMFS expects serious injury or mortality to result from this
activity and, therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
Vineyard Wind proposes to construct an 800 megawatt (mw) offshore
wind energy project in Lease Area OCS-A 0501, offshore Massachusetts.
The project would consist of up to 100 offshore wind turbine generators
(WTGs) and one or more electrical service platforms (ESPs), an onshore
substation, offshore and onshore cabling, and onshore operations and
maintenance facilities. Take of marine mammals may occur incidental to
the construction of the project due to in-water noise exposure
resulting from pile driving activities associated with installation of
WTG and ESP foundations.
[[Page 18347]]
Vineyard Wind intends to install the WTGs and ESPs between April
and December in the northeast portion of the 675 square kilometer
(km\2\) (166,886 acre) Lease Area, referred to as the Wind Development
Area (WDA) (See Figure 1 in the IHA application).
Dates and Duration
Construction of the project is planned to commence between August
1, 2020--October 1, 2020. Up to 102 days of pile driving may occur
between May 1 and December 31; no pile driving activities would occur
from January 1 through April 30.
Specific Geographic Region
Vineyard Wind's proposed activity would occur in the northern
portion of the 675 square kilometer (km) (166,886 acre) Vineyard Wind
Lease Area OCS-A 0501 (Figure 1 in the IHA application), also referred
to as the WDA. At its nearest point, the WDA is just over 23 km (14 mi)
from the southeast corner of Martha's Vineyard and a similar distance
from Nantucket. Water depths in the WDA range from approximately 37-
49.5 meters (m) (121-162 feet (ft)).
Detailed Description of Specific Activity
Vineyard Wind is proposing to construct an 800 mw commercial wind
energy project in Lease Area OCS-A 0501, offshore Massachusetts. The
Project would consist of up to 100 offshore WTGs and as many as two
ESPs, an onshore substation, offshore and onshore cabling, and onshore
operations and maintenance facilities. Vineyard Wind intends to install
the WTGs and ESPs in the northeast portion of the WDA (see Figure 1 in
the IHA application). WTGs would be arranged in a grid-like pattern
with spacing of 1.4-1.9 km (0.76-1.0 nm) between turbines. Each WTG
would interconnect with the ESP(s) via an inter-array submarine cable
system. The offshore export cable transmission system would connect the
ESP(s) to a landfall location in either Barnstable or Yarmouth,
Massachusetts. Construction of the project, including pile driving,
could occur on any day from May through December. Activities associated
with the construction of the project are described in more detail
below.
Cable Laying
Cable burial operations will occur both in the WDA for the inter-
array cables connecting the WTGs to the ESPs and in the offshore export
cable corridor (OECC) for the cables carrying power from the ESPs to
land. Inter-array cables will connect radial ``strings'' of six to 10
WTGs to the ESPs. Up to a maximum of two offshore export cables will
connect the offshore ESPs to the shore. An inter-link cable will
connect the ESPs to each other. The offshore export and inter-array
cables will be buried beneath the seafloor at a target depth of up to
1.5-2.5 m (5-8 ft). Installation of an offshore export cable is
anticipated to last ~16 days. The estimated installation time for the
inter-array cables is ~60 days. Installation days are not continuous
and do not include equipment preparation or down time that may result
from weather or maintenance.
Some dredging may be required prior to cable laying due to the
presence of sand waves. The upper portions of sand waves may be removed
via mechanical or hydraulic means in order to achieve the proper burial
depth below the stable sea bottom. The majority of the export and
inter-link cable is expected to be installed using simultaneous lay and
bury via jet plowing. Jet plowing entails the use of an adjustable
blade, or plow, which rests on the sea floor and is towed by a surface
vessel. The plow creates a narrow trench at the desired depth, while
water jets fluidize the sediment within the trench. The cable is then
fed through the plow and is laid into the trench as it moves forward.
The fluidized sediments then settle back down into the trench and bury
the cable. Jet plow technology has been shown to minimize impacts to
marine habitat and excessive dispersion of bottom sediments. The
majority of the inter-array cable is also expected to be installed via
jet plowing after the cable has been placed on the seafloor. Other
methods, such as mechanical plowing or trenching, may be needed in
areas of coarser or more consolidated sediment, rocky bottom, or other
difficult conditions in order to ensure a proper burial depth. The jet
plowing tool may be based from a seabed tractor or a sled deployed from
a vessel. A mechanical plow is also deployed from a vessel. More
information on cable laying associated with the proposed project is
provided in Vineyard Wind's COP (Vineyard Wind, 2018b). As the only
potential impacts from these activities is sediment suspension, the
potential for take to result from these activities is so low as to be
discountable; therefore these activities are not analyzed further in
this document.
Construction-Related Vessel Activity
During construction of the project, Vineyard Wind anticipates that
an average of approximately 25 vessels will operate during a typical
work day in the WDA and along the OECC. Many of these vessels will
remain in the WDA or OECC for days or weeks at a time, potentially
making only infrequent trips to port for bunkering and provisioning, as
needed. Therefore, although an average of ~25 vessels will be involved
in construction activities on any given day, fewer vessels will transit
to and from New Bedford Harbor or a secondary port each day. The actual
number of vessels involved in the project at one time is highly
dependent on the project's final schedule, the final design of the
project's components, and the logistics needed to ensure compliance
with the Jones Act, a Federal law that regulates maritime commerce in
the United States.
Existing vessel traffic in the vicinity of the project area south
of Massachusetts is relatively high; therefore, marine mammals in the
area are presumably habituated to vessel noise. In addition,
construction vessels would be stationary on site for significant
periods of time and the large vessels would travel to and from the site
at relatively low speeds. Project-related vessels would be required to
adhere to several mitigation measures designed to reduce the potential
for marine mammals to be struck by vessels associated with the project;
these measures are described further below (see Proposed Mitigation
Measures). As part of various construction related activities,
including cable laying and construction material delivery, dynamic
positioning thrusters may be utilized to hold vessels in position or
move slowly. Sound produced through use of dynamic positioning
thrusters is similar to that produced by transiting vessels and dynamic
positioning thrusters are typically operated either in a similarly
predictable manner or used for short durations around stationary
activities. Sound produced by dynamic positioning thrusters would be
preceded by, and associated with, sound from ongoing vessel noise and
would be similar in nature; thus, any marine mammals in the vicinity of
the activity would be aware of the vessel's presence, further reducing
the potential for startle or flight responses on the part of marine
mammals. Construction related vessel activity, including the use of
dynamic positioning thrusters, is not expected to result in take of
marine mammals and NMFS does not propose to authorize any takes
associated with construction related vessel activity. Accordingly,
these activities are not analyzed further in this document.
Installation of WTGs and ESPs
Two foundation types are proposed for the project: Monopiles and
jackets.
[[Page 18348]]
A monopile is a single, hollow cylinder fabricated from steel that
is secured in the seabed. Monopiles have been used successfully at many
offshore wind energy locations, including in Europe where they account
for more than 80 percent of the installed foundations. The largest
potential pile diameter proposed for the project for monopile
foundations would be 10.3 m (33.8 ft). Piles for monopile foundations
would be constructed for specific locations with maximum diameters
ranging from ~8 m (26.2 ft) up to 10.3 m (33.8 ft) and an expected
median diameter of ~9 m (29.5 ft). The piles for the monopile
foundations are up to 95 m (311.7 ft) in length and will be driven to a
penetration depth of 20-45 m (65.6-147.6 ft) (mean penetration depth 30
m (98.4 ft)). A schematic diagram showing potential heights and
dimensions of the various components of a monopile foundation are shown
in Figure 2 of the IHA application.
The jacket design concept consists of three to four steel piles, a
large lattice jacket structure, and a transition piece. Jacket
foundations each require the installation of three to four jacket
securing piles, known as jacket piles, of ~3 m (9.8 ft) diameter. The 3
m (9.8 ft) diameter jacket piles for the jacket foundations are up to
~65 m (213.3 ft) in length and would be driven to a penetration depth
of 30-75 m (98.4-196.9 ft) (mean penetration depth of 45 m (147. ft)).
A schematic diagram showing potential heights and dimensions of the
various components of a jacket foundation are shown in Figure 3 of the
IHA application.
WTGs and ESPs may be placed on either type of foundation. Vineyard
Wind has proposed that up to 100 WTG foundations may be constructed and
that, of those 100 foundations, no more than 10 may be jackets. In
addition, either one or two ESPs would be built on a jacket
foundation(s). Therefore up to 102 foundations may be installed in the
WDA. Vineyard Wind has incorporated more than one design scenario in
their planning of the project. This approach, called the ``design
envelope'' concept, allows for flexibility on the part of the
developer, in recognition of the fact that offshore wind technology and
installation techniques are constantly evolving and exact
specifications of the project are not yet certain as of the publishing
of this document. Variables that are not yet certain include the
number, size, and configuration of WTGs and ESPs and their foundations,
and the number of foundations that may be installed per day (a maximum
of two foundations would be installed per day). The flexibility
provided in the envelope concept is important because it precludes the
need for numerous authorization modifications as infrastructure or
construction techniques evolve after authorizations are granted but
before construction commences. Under a scenario where 100 WTGs are
installed on monopiles, a total of as many as 108 piles may be driven
(i.e., 100 monopiles for WTG foundations and 8 jacket piles for two
ESPs). Under a scenario where 90 WTGs are installed on monopiles and 10
WTGs are installed on jacket foundations, a total of as many as 138
piles may be driven (i.e., 90 monopiles for WTG foundations, 40 jacket
piles for WTG foundations, and 8 jacket piles for ESPs). Specifications
for both foundation types are shown in Table 1.
Table 1--Foundation Types and Specifications for the Vineyard Wind Project
----------------------------------------------------------------------------------------------------------------
Maximum number
Foundation type Pile diameter Pile length Penetration depth that may be
installed *
----------------------------------------------------------------------------------------------------------------
Monopile...................... ~8 to ~10.3 m (26.2 ~60 m up to ~95 m 20-45 m (65.6-147.6 100
to 33.8 ft). (196.9-311.7 ft). ft).
Jacket........................ 3 m (9.8 ft)........ ~65 m (213.3 ft).... 30-75 m (98.4-196.9 12
ft).
----------------------------------------------------------------------------------------------------------------
* The total of all foundations installed would not exceed 102.
The monopile and jacket foundations would be installed by one or
two heavy lift or jack-up vessels. The main installation vessel(s) will
likely remain at the WDA during the installation phase and transport
vessels, tugs, and/or feeder barges would provide a continuous supply
of foundations to the WDA. If appropriate vessels are available, the
foundation components could be picked up directly in the marshalling
port by the main installation vessel(s).
At the WDA, the main installation vessel would upend the monopile
with a crane, and place it in the gripper frame, before lowering the
monopile to the seabed. The gripper frame, depending upon its design,
may be placed on the seabed scour protection materials to stabilize the
monopile's vertical alignment before and during piling. Scour
protection is included to protect the foundation from scour
development, which is the removal of the sediments near structures by
hydrodynamic forces, and consists of the placement of stone or rock
material around the foundation. The scour protection would be one to
two m high (3-6 ft), with stone or rock sizes of approximately 10-30
centimeters (4-12 inches). Once the monopile is lowered to the seabed,
the crane hook would be released, and the hydraulic hammer would be
picked up and placed on top of the monopile. Figure 4 of the IHA
application shows a vessel lowering a monopile and typical jack-up
installation vessels.
A typical pile driving operation is expected to take less than
approximately three hours to achieve the target penetration depth. It
is anticipated that a maximum of two monopiles could potentially be
driven into the seabed per day. Concurrent driving (i.e., the driving
of more than one pile at the same time) would not occur.
Impact pile driving entails the use of a hammer that utilizes a
rising and falling piston to repeatedly strike a pile and drive it into
the ground. Using a crane, the installation vessel would upend the
monopile, place it in the gripper frame, and then lower the monopile to
the seabed. The gripper frame would stabilize the monopile's vertical
alignment before and during piling. Once the monopile is lowered to the
seabed, the crane hook would be released and the hydraulic hammer would
be picked up and placed on top of the monopile. A temporary steel cap
called a helmet would be placed on top of the pile to minimize damage
to the head during impact driving. The intensity (i.e., hammer energy
level) would be gradually increased based on the resistance that is
experienced from the sediments. The expected hammer size for monopiles
is up to 4,000 kilojoules (kJ) (however, required energy may ultimately
be far less than 4,000 kJ).
[[Page 18349]]
The typical pile driving operation is expected to take less than
approximately three hours to achieve the target penetration depth. It
is anticipated that a maximum of two piles can be driven into the
seabed per day. Impact pile driving is the preferred method of pile
installation for the proposed project.
In order to initiate impact pile driving the pile must be upright,
level, and stable. The preferred option to achieve this is by utilizing
a pile frame, which sits on the sea floor and holds the pile or to use
a pile gripper as described above. In the unlikely scenario that both
preferred options have unforeseen challenges, vibratory hammering may
be utilized as a contingency. Vibratory hammering is accomplished by
rapidly alternating (~250 Hz) forces to the pile. A system of counter-
rotating eccentric weights powered by hydraulic motors are designed
such that horizontal vibrations cancel out, while vertical vibrations
are transmitted into the pile. The vibrations produced cause
liquefaction of the substrate surrounding the pile, enabling the pile
to be driven into the ground using the weight of the pile plus the
impact hammer. If required, a vibratory hammer would be used before
impact hammering begins to ensure the pile is stable in the seabed and
is level for impact hammering. However, as stated above, impact driving
is the preferred method of pile installation and vibratory driving
would only occur for very short periods of time and only if Vineyard
Wind engineers determine vibratory driving is required to seat the
pile. The degree of potential effects of underwater sound on marine
mammals is intrinsically related to the signal characteristics,
received level, distance from the source, and duration of the sound
exposure. If vibratory pile driving were required, Vineyard Wind
anticipates that any vibratory pile driving would occur for less than
10 minutes per pile, in rare cases up to 30 minutes, as it would be
used only to seat a pile such that impact driving can commence
(Vineyard Wind, 2019). If vibratory driving does occur, the noise
resulting from this activity would occur only sporadically, and for
very brief periods when it does occur. Additionally, the source levels
and source characteristics associated with vibratory driving would be
generally similar to those produced through other concurrent use of
vessels and related construction equipment, such that behavioral
harassment of marine mammals cannot reasonably be attributed to use of
the vibratory hammer in this case. Vibratory driving produces a
continuous sound with peak sound levels that are much lower than those
resulting from impact pile driving. Any elevated noise levels produced
through vibratory driving are expected to be intermittent, of short
duration, and with low peak values. As such, we expect that if marine
mammals are exposed to sound from vibratory pile driving, they may
alert to the sound but are unlikely to exhibit a behavioral response
that rises to the level of take. As such, vibratory driving is not
analyzed further in this document.
The intensity (i.e., hammer energy level) of impact pile driving
would be gradually increased based on the resistance that is
experienced from the sediments. The expected maximum hammer energy for
monopiles is 4,000 kilojoules (kJ). However, typical energy use is
anticipated to be far less than 4,000 kJ. When piles are driven with
impact hammers, they deform, sending a bulge travelling down the pile
that radiates sound into the surrounding air, water, and seabed. This
sound may be received by biological receivers such as marine mammals
through the water, as the result of reflected paths from the surface,
or re-radiated into the water from the seabed (See Figure 5 in the IHA
application for a schematic diagram illustrating sound propagation
paths associated with pile driving). Underwater sound produced during
impact pile driving during construction of the WTGs and ESPs could
result in incidental take of marine mammals by Level B harassment and,
for some species, Level A harassment.
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 IHA 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' Stock Assessment Reports (SARs;
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS'
website (www.fisheries.noaa.gov/find-species).
There are 42 marine mammal species that have been documented within
the US Atlantic Exclusive Economic Zone (EEZ). However, 16 of these
species are not expected to occur within the project area, based on a
lack of sightings in the area and their known habitat preferences and
distributions. These are: the West Indian manatee (Trichechus manatus
latirostris), Bryde's whale (Balaenoptera edeni), beluga whale
(Delphinapterus leucas), northern bottlenose whale (Hyperoodon
ampullatus), killer whale (Orcinus orca), pygmy killer whale (Feresa
attenuata), false killer whale (Pseudorca crassidens), melon-headed
whale (Peponocephala electra), white-beaked dolphin (Lagenorhynchus
albirostris), pantropical spotted dolphin (Stenella attenuata),
Fraser's dolphin (Lagenodelphis hosei), rough-toothed dolphin (Steno
bredanensis), Clymene dolphin (Stenella clymene), spinner dolphin
(Stenella longirostris), hooded seal (Cystophora cristata), and ringed
seal (Pusa hipsida). These species are not analyzed further in this
document.
There are 26 marine mammal species that could potentially occur in
the proposed project area and that are included in Table 3 of the IHA
application. However, the temporal and/or spatial occurrence of several
species listed in Table 3 of the IHA application is such that take of
these species is not expected to occur, and they are therefore not
discussed further beyond the explanation provided here. Take of these
species is not anticipated either because they have very low densities
in the project area, or because they are not expected to occur in the
project area due to their more likely occurrence in habitat that is
outside the WDA, based on the best available information. There are two
pilot whale species (long-finned and short-finned (Globicephala
macrorhynchus)) with distributions that overlap in the latitudinal
range of the WDA (Hayes et al., 2017; Roberts et al., 2016). Because it
is difficult to discriminate the two species at sea, sightings, and
thus the densities calculated from them, are generally reported
together as Globicephala spp. (Hayes et al., 2018; Roberts et al.,
2016). However, based on the best available information, short-finned
pilot whales occur in habitat that is both further offshore on the
shelf break and further south than the project area (Hayes et al.,
2018). Therefore, we assume that any take of pilot whales would be of
long-finned pilot whales. Blue whales (Balaenoptera musculus musculus),
dwarf and pygmy sperm whales (Kogia sima and K. breviceps), Cuvier's
beaked whale (Ziphius cavirostris), striped dolphins (Stenella
coeruleoalba) and
[[Page 18350]]
four species of Mesoplodont beaked whale (Mesoplodon spp.), also occur
in deepwater habitat that is further offshore than the project area
(Hayes et al., 2018, Roberts et al., 2016). Likewise, Atlantic spotted
dolphins (Stenella frontalis) primarily occur near the continental
shelf edge and continental slope, in waters that are further offshore
than the project area (Hayes et al., 2018).
Between October 2011 and June 2015 a total of 76 aerial surveys
were conducted throughout the MA and RI/MA Wind Energy Areas (WEAs)
(the WDA is contained within the MA WEA along with several other
offshore renewable energy lease areas). Between November 2011 and March
2015, Marine Autonomous Recording Units (MARU; a type of static passive
acoustic monitoring (PAM) recorder) were deployed at nine sites in the
MA and RI/MA WEAs. The goal of the study was to collect visual and
acoustic baseline data on distribution, abundance, and temporal
occurrence patterns of marine mammals (Kraus et al., 2016). The lack of
sightings of any of the species listed above reinforces the fact that
these species are not expected to occur in the project area. As these
species are not expected to occur in the project area during the
proposed activities, they are not discussed further in this document.
We expect that the species listed in Table 2 will potentially occur
in the project area and will potentially be taken as a result of the
proposed project. Table 2 summarizes information related to the
population or stock, including regulatory status under the 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' SARs). While no mortality is anticipated or authorized here, PBR
is included here as a gross indicator 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' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Atlantic SARs. All values presented in Table 2 are the most
recent available at the time of publication and are available in the
2017 Atlantic SARs (Hayes et al., 2018) or draft 2018 SARs, available
online at: www.fisheries.noaa.gov/action/2018-draft-marine-mammal-stock-assessment-reports-available.
Table 2--Marine Mammals Known To Occur in the Project Area That May Be Affected by Vineyard Wind's Proposed Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
MMPA and ESA Stock abundance
status; (CV, Nmin, most Predicted Annual M/ Occurrence and
Common name (scientific name) Stock strategic (Y/ recent abundance abundance (CV) \3\ PBR \4\ SI \4\ seasonality in
N) \1\ survey) \2\ project area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Toothed whales (Odontoceti)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale (Physeter North Atlantic..... E; Y 2,288 (0.28; 1,815; 5,353 (0.12)...... 3.6 0.8 Rare.
macrocephalus). n/a).
Long-finned pilot whale W North Atlantic... -; N 5,636 (0.63; 3,464; 18,977 (0.11) \5\. 35 27 Rare.
(Globicephala melas). n/a).
Atlantic white-sided dolphin W North Atlantic... -; N 48,819 (0.61; 37,180 (0.07)..... 304 30 Common year round.
(Lagenorhynchus acutus). 30,403; n/a).
Bottlenose dolphin (Tursiops W North Atlantic, -; N 77,532 (0.40; 97,476 (0.06)\5\.. 561 39.4 Common year round.
truncatus). Offshore. 56,053; 2011).
Common dolphin \6\ (Delphinus W North Atlantic... -; N 173,486 (0.55; 86,098 (0.12)..... 557 406 Common year round.
delphis). 55,690; 2011).
Risso's dolphin (Grampus W North Atlantic... -; N 18,250 (0.46; 7,732 (0.09)...... 126 49.9 Rare.
griseus). 12,619; 2011).
Harbor porpoise (Phocoena Gulf of Maine/Bay -; N 79,833 (0.32; 45,089 (0.12)*.... 706 255 Common year round.
phocoena). of Fundy. 61,415; 2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baleen whales (Mysticeti)
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale W North Atlantic... E; Y 451 (0; 455; n/a).. 535 (0.45)*....... 0.9 56 Year round in
(Eubalaena glacialis). continental shelf
and slope waters,
occur seasonally.
Humpback whale \7\ (Megaptera Gulf of Maine...... -; N 896 (0.42; 239; n/ 1,637 (0.07)*..... 14.6 9.8 Common year round.
novaeangliae). a).
Fin whale \6\ (Balaenoptera W North Atlantic... E; Y 3,522 (0.27; 1,234; 4,633 (0.08)...... 2.5 2.5 Year round in
physalus). n/a). continental shelf
and slope waters,
occur seasonally.
Sei whale (Balaenoptera Nova Scotia........ E; Y 357 (0.52; 236; n/ 717 (0.30)*....... 0.5 0.6 Year round in
borealis). a). continental shelf
and slope waters,
occur seasonally.
Minke whale \6\ (Balaenoptera Canadian East Coast -; N 20,741 (0.3; 1,425; 2,112 (0.05)*..... 14 7.5 Year round in
acutorostrata). n/a). continental shelf
and slope waters,
occur seasonally.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Earless seals (Phocidae)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray seal \8\ (Halichoerus W North Atlantic... -; N 27,131 (0.10; .................. 1,389 5,688 Common year round.
grypus). 25,908; n/a).
Harbor seal (Phoca vitulina).... W North Atlantic... -; N 75,834 (0.15; .................. 2,006 345 Common year round.
66,884; 2012).
[[Page 18351]]
Harp seal (Pagophilus W North Atlantic... -; N 7,411,000 (unk.; .................. unk 225,687 Rare.
groenlandicus). unk; 2014).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ 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 (see
footnote 3) 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\Stock abundance as reported in NMFS marine mammal stock assessment reports (SAR) except where otherwise noted. SARs available online at:
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments. CV is coefficient of variation; Nmin is the minimum estimate
of stock abundance. In some cases, CV is not applicable. For certain stocks, abundance estimates are actual counts of animals and there is no
associated CV. The most recent abundance survey that is reflected in the abundance estimate is presented; there may be more recent surveys that have
not yet been incorporated into the estimate. All values presented here are from the 2018 draft Atlantic SARs.
\3\ This information represents species- or guild-specific abundance predicted by recent habitat-based cetacean density models (Roberts et al., 2016,
2017, 2018). These models provide the best available scientific information regarding predicted density patterns of cetaceans in the U.S. Atlantic
Ocean, and we provide the corresponding abundance predictions as a point of reference. Total abundance estimates were produced by computing the mean
density of all pixels in the modeled area and multiplying by its area. For those species marked with an asterisk, the available information supported
development of either two or four seasonal models; each model has an associated abundance prediction. Here, we report the maximum predicted abundance.
\4\ Potential biological removal, 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 size (OSP). Annual M/SI, found in NMFS' SARs,
represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, subsistence hunting, ship
strike). Annual M/SI values often cannot be determined precisely and is in some cases presented as a minimum value. All M/SI values are as presented
in the draft 2018 SARs.
\5\Abundance estimates are in some cases reported for a guild or group of species when those species are difficult to differentiate at sea. Similarly,
the habitat-based cetacean density models produced by Roberts et al. (2016) are based in part on available observational data which, in some cases, is
limited to genus or guild in terms of taxonomic definition. Roberts et al. (2016) produced density models to genus level for Globicephala spp. and
produced a density model for bottlenose dolphins that does not differentiate between offshore and coastal stocks.
\6\ Abundance as reported in the 2007 Canadian Trans-North Atlantic Sighting Survey (TNASS), which provided full coverage of the Atlantic Canadian coast
(Lawson and Gosselin, 2009). Abundance estimates from TNASS were corrected for perception and availability bias, when possible. In general, where the
TNASS survey effort provided superior coverage of a stock's range (as compared with NOAA shipboard survey effort), the resulting abundance estimate is
considered more accurate than the current NMFS abundance estimate (derived from survey effort with inferior coverage of the stock range). NMFS stock
abundance estimate for the common dolphin is 70,184. NMFS stock abundance estimate for the fin whale is 1,618. NMFS stock abundance estimate for the
minke whale is 2,591.
\7\ 2018 U.S. Atlantic draft 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.
\8\ NMFS stock abundance estimate applies to U.S. population only, actual stock abundance is approximately 505,000.
Four marine mammal species that are listed under the Endangered
Species Act (ESA) may be present in the project area and may be taken
incidental to the proposed activity: The North Atlantic right whale,
fin whale, sei whale, and sperm whale.
Below is a description of the species that are both common in the
project area south of Massachusetts that have the highest likelihood of
occurring in the project area and are thus expected to potentially be
taken by the proposed activities. For the majority of species
potentially present in the specific geographic region, NMFS has
designated only a single generic stock (e.g., ``western North
Atlantic'') for management purposes. This includes the ``Canadian east
coast'' stock of minke whales, which includes all minke whales found in
U.S. waters is also a generic stock for management purposes. For
humpback and sei whales, NMFS defines stocks on the basis of feeding
locations, i.e., Gulf of Maine and Nova Scotia, respectively. However,
references to humpback whales and sei whales in this document refer to
any individuals of the species that are found in the specific
geographic region. Any biologically important areas (BIAs) that overlap
spatially with the project area are addressed in the species sections
below.
North Atlantic Right Whale
The North Atlantic right whale ranges from calving grounds in the
southeastern United States to feeding grounds in New England waters and
into Canadian waters (Hayes et al., 2018). Surveys have demonstrated
the existence of seven areas where North Atlantic right whales
congregate seasonally, including north and east of the proposed project
area in Georges Bank, off Cape Cod, and in Massachusetts Bay (Hayes et
al., 2018). In the late fall months (e.g., October), right whales are
generally thought to depart from the feeding grounds in the North
Atlantic and move south to their calving grounds off Georgia and
Florida. However, recent research indicates our understanding of their
movement patterns remains incomplete (Davis et al., 2017). A review of
passive acoustic monitoring data from 2004 to 2014 throughout the
western North Atlantic demonstrated nearly continuous year-round right
whale presence across their entire habitat range (for at least some
individuals), including in locations previously thought of as migratory
corridors, suggesting that not all of the population undergoes a
consistent annual migration (Davis et al., 2017). Acoustic monitoring
data from 2004 to 2014 indicated that the number of North Atlantic
right whale vocalizations detected in the proposed project area were
relatively constant throughout the year, with the exception of August
through October when detected vocalizations showed an apparent decline
(Davis et al., 2017).
The western North Atlantic population demonstrated overall growth
of 2.8 percent per year between 1990 to 2010, despite a decline in 1993
and no growth between 1997 and 2000 (Pace et al., 2017). However, since
2010 the population has been in decline, with a 99.99 percent
probability of a decline of just under 1 percent per year (Pace et al.,
2017). Between 1990 and 2015, calving rates varied substantially, with
low calving rates coinciding with all three periods of decline or no
growth (Pace et al., 2017). On average, North Atlantic right whale
calving rates are estimated to be roughly half that of southern right
whales (Eubalaena australis) (Pace et al., 2017), which are increasing
in abundance (NMFS 2015). In 2018, no new North Atlantic right whale
calves were documented in their calving grounds; this represented the
first time since annual NOAA aerial surveys began in 1989 that no new
right whale calves were observed. As of the writing of this document, 7
calves had been documented thus far in 2019. The current best estimate
of population abundance for the species is 411
[[Page 18352]]
individuals, based on data as of September 4, 2018 (Pettis et al.,
2018).
Elevated North Atlantic right whale mortalities have occurred since
June 7, 2017 along the United States and Canadian coast. A total of 20
confirmed dead stranded whales (12 in Canada; 8 in the United States)
have been documented, with 17 of those occurring in 2017. This event
has been declared an Unusual Mortality Event (UME), with human
interactions, including entanglement in fixed fishing gear and vessel
strikes, implicated in 10 of the 20 mortalities. There had been no
North Atlantic right whale standings reported in 2019 as of the
publication of this document. More information is available online at:
www.fisheries.noaa.gov/national/marine-life-distress/2017-2019-north-atlantic-right-whale-unusual-mortality-event.
During the aerial surveys conducted from 2011-2015 in the project
area, the highest number of right whale sightings occurred in March (n
= 21), with sightings also occurring in December (n = 4), January (n =
7), February (n = 14), and April (n = 14), and no sightings in any
other months (Kraus et al., 2016). There was not significant
variability in sighting rate among years, indicating consistent annual
seasonal use of the area by right whales. North Atlantic right whales
were acoustically detected in 30 out of the 36 recorded months (Kraus
et al., 2016). However, right whales exhibited strong seasonality in
acoustic presence, with mean monthly acoustic presence highest in
January (mean = 74%), February (mean = 86%), and March (mean = 97%),
and the lowest in July (mean = 16%), August (mean = 2%), and September
(mean = 12%). Density data from Roberts et al. (2017) confirms that the
highest density of right whales in the project area occurs in March.
The proposed project area is part of an important migratory area for
North Atlantic right whales; this important migratory area is comprised
of the waters of the continental shelf offshore the East Coast of the
United States and extends from Florida through Massachusetts. Aerial
surveys conducted in and near the project area from 2011-2015
documented a total of six instances of feeding behavior by North
Atlantic right whales (Kraus et al., 2016), however the area has not
been identified as an important feeding area for right whales.
NMFS' regulations at 50 CFR 224.105 designated nearshore waters of
the Mid-Atlantic Bight as Mid-Atlantic U.S. Seasonal Management Areas
(SMA) for right whales in 2008. SMAs were developed to reduce the
threat of collisions between ships and right whales around their
migratory route and calving grounds. A portion of one SMA, which occurs
off Block Island, Rhode Island, occurs near the project area, but does
not overlap spatially with the project area (see Figure 7 in the IHA
application). The SMA that occurs off Block Island is active from
November 1 through April 30 of each year.
Humpback Whale
Humpback whales are found worldwide in all oceans. Humpback whales
were listed as endangered under the Endangered Species Conservation Act
(ESCA) in June 1970. In 1973, the ESA replaced the ESCA, and humpbacks
continued to be listed as endangered. NMFS recently evaluated the
status of the species, and on September 8, 2016, NMFS divided the
species into 14 distinct population segments (DPS), removed the current
species-level listing, and in its place listed four DPSs as endangered
and one DPS as threatened (81 FR 62259; September 8, 2016). The
remaining nine DPSs were not listed. The West Indies DPS, which is not
listed under the ESA, is the only DPS of humpback whale that is
expected to occur in the project area.
In New England waters, feeding is the principal activity of
humpback whales, and their distribution in this region has been largely
correlated to abundance of prey species, although behavior and
bathymetry are factors influencing foraging strategy (Payne et al.,
1986, 1990). Humpback whales are frequently piscivorous when in New
England waters, feeding on herring (Clupea harengus), sand lance
(Ammodytes spp.), and other small fishes, as well as euphausiids in the
northern Gulf of Maine (Paquet et al., 1997). During winter, the
majority of humpback whales from North Atlantic feeding areas
(including the Gulf of Maine) mate and calve in the West Indies, where
spatial and genetic mixing among feeding groups occurs, though
significant numbers of animals are found in mid- and high-latitude
regions at this time and some individuals have been sighted repeatedly
within the same winter season, indicating that not all humpback whales
migrate south every winter (Hayes et al., 2018).
In aerial surveys conducted from 2011-2015 in the project area,
sightings of humpback whales occurred during all seasons, however they
were primarily sighted in the spring and summer seasons, with the
greatest number of sightings during the month of April (n=33). Based on
the pattern of sightings during those years their presence in the area
seemed to start in March and end in July, though a few sightings also
occurred in October, December and January (Kraus et al., 2016).
Since January 2016, elevated humpback whale mortalities have
occurred along the Atlantic coast from Maine to Florida. Partial or
full necropsy examinations have been conducted on approximately half of
the 93 known cases. Of the whales examined, about 50 percent had
evidence of human interaction, either ship strike or entanglement.
While a portion of the whales have shown evidence of pre-mortem vessel
strike, this finding is not consistent across all whales examined and
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. Three previous UMEs involving humpback whales
have occurred since 2000, in 2003, 2005, and 2006. More information is
available at: www.fisheries.noaa.gov/national/marine-life-distress/2016-2019-humpback-whale-unusual-mortality-event-along-atlantic-coast.
Fin Whale
Fin whales are common in waters of the U.S. Atlantic EEZ,
principally from Cape Hatteras northward (Hayes et al., 2018). Fin
whales are present north of 35-degree latitude in every season and are
broadly distributed throughout the western North Atlantic for most of
the year, though densities vary seasonally (Hayes et al., 2018). In
this region fin whales are the dominant large cetacean species during
all seasons, having the largest standing stock, the largest food
requirements, and therefore the largest influence on ecosystem
processes of any cetacean species (Hain et al., 1992; Kenney et al.,
1997). It is likely that fin whales occurring in the U.S. Atlantic EEZ
undergo migrations into Canadian waters, open-ocean areas, and perhaps
even subtropical or tropical regions (Edwards et al., 2015).
New England waters represent a major feeding ground for fin whales
and a biologically important feeding area for the species exists just
west of the proposed project area, stretching from just south of the
eastern tip of Long Island to south of the western tip of Martha's
Vineyard. In aerial surveys conducted from 2011-2015 in the project
area sightings occurred in every season with the greatest numbers of
sightings during the spring (n=35) and summer (n=49) months (Kraus et
al.,
[[Page 18353]]
2016). Despite much lower sighting rates during the winter, confirmed
acoustic detections of fin whales recorded on a hydrophone array in the
project area from 2011-2015 occurred throughout the year; however, due
to acoustic detection ranges in excess of 200 km, the detections do not
confirm that fin whales were present in the project area during that
time (Kraus et al., 2016).
Sei Whale
The Nova Scotia stock of sei whales can be found in deeper waters
of the continental shelf edge waters of the northeastern United States
and northeastward to south of Newfoundland. The southern portion of the
stock's range during spring and summer includes the Gulf of Maine and
Georges Bank. Spring is the period of greatest abundance in U.S.
waters, with sightings concentrated along the eastern margin of Georges
Bank and into the Northeast Channel area, and along the southwestern
edge of Georges Bank in the area of Hydrographer Canyon (Hayes et al.,
2018). Sei whales occur in shallower waters to feed. Sei whales were
only sighted during the spring and summer. In aerial surveys conducted
from 2011-2015 in the project area sightings of Sei whales occurred
between March and June, with the greatest number of sightings in May
(n=8) and June (n=13), and no sightings from July through January
(Kraus et al., 2016).
Minke Whale
Minke whales occur in temperate, tropical, and high-latitude
waters. The Canadian East Coast stock can be found in the area from the
western half of the Davis Strait (45[deg] W) to the Gulf of Mexico
(Hayes et al., 2018). This species generally occupies waters less than
100 m deep on the continental shelf. There appears to be a strong
seasonal component to minke whale distribution in which spring to fall
are times of relatively widespread and common occurrence, and when the
whales are most abundant in New England waters, while during winter the
species appears to be largely absent (Hayes et al., 2016). In aerial
surveys conducted from 2011-2015 in the project area sightings of minke
whales occurred between March and September, with the greatest number
of sightings occurring in May (n=38) and no sightings from October
through February (Kraus et al., 2016).
Since January 2017, elevated minke whale mortalities have occurred
along the Atlantic coast from Maine through South Carolina, with a
total of 59 strandings recorded when this document was written. This
event has been declared a UME. Full or partial necropsy examinations
were conducted on more than 60 percent of the whales. Preliminary
findings in several of the whales have shown evidence of human
interactions or infectious disease, but these findings are not
consistent across all of the whales examined, so more research is
needed. More information is available at: www.fisheries.noaa.gov/national/marine-life-distress/2017-2019-minke-whale-unusual-mortality-event-along-atlantic-coast.
Sperm Whale
The distribution of the sperm whale in the U.S. EEZ occurs on the
continental shelf edge, over the continental slope, and into mid-ocean
regions (Hayes et al., 2018). The basic social unit of the sperm whale
appears to be the mixed school of adult females plus their calves and
some juveniles of both sexes, normally numbering 20-40 animals in all.
There is evidence that some social bonds persist for many years
(Christal et al., 1998). In summer, the distribution of sperm whales
includes the area east and north of Georges Bank and into the Northeast
Channel region, as well as the continental shelf (inshore of the 100-m
isobath) south of New England. In the fall, sperm whale occurrence
south of New England on the continental shelf is at its highest level,
and there remains a continental shelf edge occurrence in the mid-
Atlantic bight. In winter, sperm whales are concentrated east and
northeast of Cape Hatteras. Sperm whales are not expected to be common
in the project area due to the relatively shallow depths in the project
area. In aerial surveys conducted from 2011-2015 in the project area
only four sightings of sperm whales occurred, three in summer and one
in autumn (Kraus et al., 2016).
Long-Finned Pilot Whale
Long-finned pilot whales are found from North Carolina and north to
Iceland, Greenland and the Barents Sea (Hayes et al., 2018). In U.S.
Atlantic waters the species is distributed principally along the
continental shelf edge off the northeastern U.S. coast in winter and
early spring and in late spring, pilot whales move onto Georges Bank
and into the Gulf of Maine and more northern waters and remain in these
areas through late autumn (Waring et al., 2016). In aerial surveys
conducted from 2011-2015 in the project area the majority of pilot
whale sightings were in spring (n=11); sightings were also documented
in summer, with no sightings in autumn or winter (Kraus et al., 2016).
Atlantic White-Sided Dolphin
White-sided dolphins are found in temperate and sub-polar waters of
the North Atlantic, primarily in continental shelf waters to the 100-m
depth contour from central West Greenland to North Carolina (Hayes et
al., 2018). The Gulf of Maine stock is most common in continental shelf
waters from Hudson Canyon to Georges Bank, and in the Gulf of Maine and
lower Bay of Fundy. Sighting data indicate seasonal shifts in
distribution (Northridge et al., 1997). During January to May, low
numbers of white-sided dolphins are found from Georges Bank to Jeffreys
Ledge (off New Hampshire), with even lower numbers south of Georges
Bank, as documented by a few strandings collected on beaches of
Virginia to South Carolina. From June through September, large numbers
of white-sided dolphins are found from Georges Bank to the lower Bay of
Fundy. From October to December, white-sided dolphins occur at
intermediate densities from southern Georges Bank to southern Gulf of
Maine (Payne and Heinemann 1990). Sightings south of Georges Bank,
particularly around Hudson Canyon, occur year round but at low
densities. In aerial surveys conducted from 2011-2015 in the project
area there were sightings of white-sided dolphins in every season
except winter (Kraus et al., 2016).
Common Dolphin
The common dolphin is found world-wide in temperate to subtropical
seas. In the North Atlantic, common dolphins are found over the
continental shelf between the 100-m and 2,000-m isobaths and over
prominent underwater topography and east to the mid-Atlantic Ridge
(Hayes et al., 2018), but may be found in shallower shelf waters as
well. Common dolphins are expected to occur in the vicinity of the
project area in relatively high numbers. Common dolphins were the most
frequently observed dolphin species in aerial surveys conducted from
2011-2015 in the project area (Kraus et al., 2016). Sightings peaked in
the summer between June and August, though there were sightings
recorded in nearly every month of the year (Kraus et al., 2016).
Bottlenose Dolphin
There are two distinct bottlenose dolphin mophotypes in the western
North Atlantic: The coastal and offshore forms (Hayes et al., 2018).
The two mophotypes are genetically distinct based upon both
mitochondrial and nuclear markers (Hoelzel et al., 1998;
[[Page 18354]]
Rosel et al., 2009). The offshore form is distributed primarily along
the outer continental shelf and continental slope in the Northwest
Atlantic Ocean from Georges Bank to the Florida Keys and is the only
type that may be present in the project area as the northern extent of
the range of the Western North Atlantic Northern Migratory Coastal
Stock occurs south of the project area. Bottlenose dolphins are
expected to occur in the project area in relatively high numbers. They
were the second most frequently observed species of dolphin in aerial
surveys conducted from 2011-2015 in the project area, and were observed
in every month of the year except January and March (Kraus et al.,
2016).
Risso's Dolphin
Risso's dolphins are distributed worldwide in tropical and
temperate seas and in the Northwest Atlantic occur from Florida to
eastern Newfoundland (Leatherwood et al., 1976; Baird and Stacey 1991).
Off the northeastern U.S. coast, Risso's dolphins are distributed along
the continental shelf edge from Cape Hatteras northward to Georges Bank
during spring, summer, and autumn (CETAP 1982; Payne et al., 1984) with
the range extending outward into oceanic waters in the winter (Payne et
al., 1984). Risso's dolphins are not expected to be common in the
project area due to the relatively shallow water depths. In aerial
surveys conducted from 2011-2015 in the project there were only two
confirmed sightings of Risso's dolphins, both of which occurred in the
spring (Kraus et al., 2016).
Harbor Porpoise
Harbor porpoises occur from the coastline to deep waters (>1800 m;
Westgate et al., 1998), although the majority of the population is
found over the continental shelf (Hayes et al., 2018). In the project
area, only the Gulf of Maine/Bay of Fundy stock of harbor porpoise may
be present. This stock is found in U.S. and Canadian Atlantic waters
and is concentrated in the northern Gulf of Maine and southern Bay of
Fundy region, generally in waters less than 150 m deep (Waring et al.,
2016). In aerial surveys conducted from 2011-2015 in the project area,
sightings of harbor porpoise occurred from November through May, with
the highest number of detections occurring in April and almost none
during June-September (Kraus et al., 2016).
Harbor Seal
The harbor seal is found in all nearshore waters of the North
Atlantic and North Pacific Oceans and adjoining seas above about
30[deg] N (Burns, 2009). In the western North Atlantic, harbor seals
are distributed from the eastern Canadian Arctic and Greenland south to
southern New England and New York, and occasionally to the Carolinas
(Hayes et al., 2018). Haulout and pupping sites are located off
Manomet, MA and the Isles of Shoals, ME (Waring et al., 2016). Based on
harbor seal sightings reported at sea in shipboard surveys conducted by
the NMFS Northeast Fisheries Science Center from 1995-2011, harbor
seals would be expected to occur in the project area from September to
May (Hayes et al., 2018). Harbor seals are expected to be relatively
common in the project area. Since July 2018, elevated numbers of harbor
seal and gray seal mortalities have occurred across Maine, New
Hampshire and Massachusetts. This event has been declared a UME.
Additionally, stranded seals have shown clinical signs as far south as
Virginia, although not in elevated numbers, therefore the UME
investigation now encompasses all seal strandings from Maine to
Virginia. Lastly, ice seals (harp and hooded seals) have also started
stranding with clinical signs, again not in elevated numbers, and those
two seal species have also been added to the UME investigation. Full or
partial necropsy examinations have been conducted on some of the seals
and samples have been collected for testing. Based on tests conducted
thus far, the main pathogen found in the seals is phocine distemper
virus. NMFS is performing additional testing to identify any other
factors that may be involved in this UME. Information on this UME is
available online at: www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2019-pinniped-unusual-mortality-event-along.
Gray Seal
There are three major populations of gray seals found in the world;
eastern Canada (western North Atlantic stock), northwestern Europe and
the Baltic Sea. Gray seals in the project area belong to the western
North Atlantic stock. The range for this stock is from New Jersey to
Labrador. Current population trends show that gray seal abundance is
likely increasing in the U.S. Atlantic EEZ (Hayes et al., 2018).
Although the rate of increase is unknown, surveys conducted since their
arrival in the 1980s indicate a steady increase in abundance in both
Maine and Massachusetts (Hayes et al., 2018). It is believed that
recolonization by Canadian gray seals is the source of the U.S.
population (Hayes et al., 2018). Gray seals are expected to be
relatively common in the project area. As described above, elevated
seal mortalities, including gray seals, have occurred across Maine, New
Hampshire and Massachusetts, and as far south as Virginia, since July
2018. This event has been declared a UME, with phocine distemper virus
identified as the main pathogen found in the seals. NMFS is performing
additional testing to identify any other factors that may be involved
in this UME.
Harp Seal
Harp seals are highly migratory and occur throughout much of the
North Atlantic and Arctic Oceans (Hayes et al., 2018). Breeding occurs
between late-February and April and adults then assemble on suitable
pack ice to undergo the annual molt. The migration then continues north
to Arctic summer feeding grounds. Harp seal occurrence in the project
area is considered rare. However, since the early 1990s, numbers of
sightings and strandings have been increasing off the east coast of the
United States from Maine to New Jersey (Katona et al., 1993; Rubinstein
1994; Stevick and Fernald 1998; McAlpine 1999; Lacoste and Stenson
2000; Soulen et al., 2013). These extralimital appearances usually
occur in January-May (Harris et al., 2002), when the western North
Atlantic stock is at its most southern point of migration. Harp seals
are not expected to be common in the project area. As described above,
elevated seal mortalities, including harp seals, have occurred across
Maine, New Hampshire and Massachusetts, and as far south as Virginia,
since July 2018. This event has been declared a UME, with phocine
distemper virus identified as the main pathogen found in the seals.
NMFS is performing additional testing to identify any other factors
that may be involved in this UME.
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, 2019) recommended that marine mammals be
divided into functional hearing groups based on directly measured or
estimated hearing ranges
[[Page 18355]]
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 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2018]
----------------------------------------------------------------------------------------------------------------
Hearing group Generalized hearing range *
----------------------------------------------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales)........... 7 Hz to 35 kHz.
Mid-frequency (MF) cetaceans (dolphins, toothed whales, 150 Hz to 160 kHz.
beaked whales, bottlenose whales).
High-frequency (HF) cetaceans (true porpoises, Kogia, 275 Hz to 160 kHz.
river dolphins, cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true seals)........ 50 Hz to 86 kHz.
Otariid pinnipeds (OW) (underwater) (sea lions and fur 60 Hz to 39 kHz.
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.
Fifteen marine mammal species (twelve cetacean and three pinniped (all
phocid species)) have the reasonable potential to co-occur with the
proposed activities. Please refer to Table 2. Of the cetacean species
that may be present, five are classified as low-frequency cetaceans
(i.e., all mysticete species), six are classified as mid-frequency
cetaceans (i.e., all delphinid species and the sperm whale), and one is
classified as a high-frequency cetacean (i.e., 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 section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
Description of Sound Sources
This section contains a brief technical background on sound, on the
characteristics of certain sound types, and on metrics used in this
proposal inasmuch as the information is relevant to the specified
activity and to a discussion of the potential effects of the specified
activity on marine mammals found later in this document. For general
information on sound and its interaction with the marine environment,
please see, e.g., Au and Hastings (2008); Richardson et al. (1995);
Urick (1983).
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in hertz (Hz) or cycles per second. Wavelength is the
distance between two peaks or corresponding points of a sound wave
(length of one cycle). Higher frequency sounds have shorter wavelengths
than lower frequency sounds, and typically attenuate (decrease) more
rapidly, except in certain cases in shallower water. Amplitude is the
height of the sound pressure wave or the ``loudness'' of a sound and is
typically described using the relative unit of the decibel (dB). A
sound pressure level (SPL) in dB is described as the ratio between a
measured pressure and a reference pressure (for underwater sound, this
is 1 microPascal ([mu]Pa)), and is a logarithmic unit that accounts for
large variations in amplitude; therefore, a relatively small change in
dB corresponds to large changes in sound pressure. The source level
(SL) represents the SPL referenced at a distance of 1 m from the source
(referenced to 1 [mu]Pa), while the received level is the SPL at the
listener's position (referenced to 1 [mu]Pa).
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Root mean square is calculated by squaring
all of the sound amplitudes, averaging the squares, and then taking the
square root of the average (Urick, 1983). Root mean square accounts for
both positive and negative values; squaring the pressures makes all
values positive so that they may be accounted for in the summation of
pressure levels (Hastings and Popper, 2005). This measurement is often
used in the context of discussing behavioral effects, in part because
behavioral effects, which often result from auditory cues, may be
better expressed through averaged units than by peak pressures.
Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s)
represents the total energy in a stated frequency band over a stated
time interval or event, and considers both intensity and duration of
exposure. The per-pulse SEL is calculated over the time window
containing the entire pulse (i.e., 100 percent of the acoustic energy).
SEL is a cumulative metric; it can be accumulated over a single pulse,
or calculated over periods containing multiple pulses. Cumulative SEL
represents the total energy accumulated by a receiver over a defined
time window or during an event. Peak sound pressure (also referred to
as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous
sound pressure
[[Page 18356]]
measurable in the water at a specified distance from the source, and is
represented in the same units as the rms sound pressure.
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in a
manner similar to ripples on the surface of a pond and may be either
directed in a beam or beams or may radiate in all directions
(omnidirectional sources), as is the case for sound produced by the
pile driving activity considered here. The compressions and
decompressions associated with sound waves are detected as changes in
pressure by aquatic life and man-made sound receptors such as
hydrophones.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound, which is
defined as environmental background sound levels lacking a single
source or point (Richardson et al., 1995). The sound level of a region
is defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., wind and
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
(e.g., vessels, dredging, construction) sound. A number of sources
contribute to ambient sound, including wind and waves, which are a main
source of naturally occurring ambient sound for frequencies between 200
hertz (Hz) and 50 kilohertz (kHz) (Mitson, 1995). In general, ambient
sound levels tend to increase with increasing wind speed and wave
height. Precipitation can become an important component of total sound
at frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times. Marine mammals can contribute significantly to ambient sound
levels, as can some fish and snapping shrimp. The frequency band for
biological contributions is from approximately 12 Hz to over 100 kHz.
Sources of ambient sound related to human activity include
transportation (surface vessels), dredging and construction, oil and
gas drilling and production, geophysical surveys, sonar, and
explosions. Vessel noise typically dominates the total ambient sound
for frequencies between 20 and 300 Hz. In general, the frequencies of
anthropogenic sounds are below 1 kHz and, if higher frequency sound
levels are created, they attenuate rapidly.
The sum of the various natural and anthropogenic sound sources that
comprise ambient sound at any given location and time depends not only
on the source levels (as determined by current weather conditions and
levels of biological and human 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 decibels (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. Underwater ambient sound in the Atlantic Ocean south of
Massachusetts is comprised of sounds produced by a number of natural
and anthropogenic sources. Human-generated sound is a significant
contributor to the ambient acoustic environment in the project
location. Details of source types are described in the following text.
Sounds are often considered to fall into one of two general types:
Pulsed and non-pulsed (defined in the following). 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). Please see
Southall et al. (2007) for an in-depth discussion of these concepts.
The distinction between these two sound types is not always obvious, as
certain signals share properties of both pulsed and non-pulsed sounds.
A signal near a source could be categorized as a pulse, but due to
propagation effects as it moves farther from the source, the signal
duration becomes longer (e.g., Greene and Richardson, 1988).
Pulsed sound sources (e.g., airguns, explosions, gunshots, sonic
booms, impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur
either as isolated events or repeated in some succession. Pulsed sounds
are all characterized by a relatively rapid rise from ambient pressure
to a maximal pressure value followed by a rapid decay period that may
include a period of diminishing, oscillating maximal and minimal
pressures, and generally have an increased capacity to induce physical
injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or intermittent (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems. The
duration of such sounds, as received at a distance, can be greatly
extended in a highly reverberant environment.
The impulsive sound generated by impact hammers is characterized by
rapid rise times and high peak levels. Vibratory hammers produce non-
impulsive, continuous noise at levels significantly lower than those
produced by impact hammers. Rise time is slower, reducing the
probability and severity of injury, and sound energy is distributed
over a greater amount of time (e.g., Nedwell and Edwards, 2002; Carlson
et al., 2005).
Acoustic Effects
We previously provided general background information on marine
mammal hearing (see ``Description of Marine Mammals in the Area of the
Specified Activity''). Here, we discuss the potential effects of sound
on marine mammals.
Potential Effects of Underwater Sound--Note that, in the following
discussion, we refer in many cases to a review article concerning
studies of noise-induced hearing loss conducted from 1996-2015 (i.e.,
Finneran, 2015). For study-specific citations, please see that work.
Anthropogenic sounds cover a broad range of frequencies and sound
levels and can have a range of highly variable impacts on marine life,
from none or minor to potentially severe responses, depending on
received levels, duration of exposure, behavioral context, and various
other factors. The potential effects of underwater sound from active
acoustic sources can potentially result in one or more of the
following: temporary or permanent hearing impairment, non-auditory
physical or physiological effects, behavioral disturbance, stress, and
masking (Richardson et al., 1995; Gordon et al., 2004; Nowacek et al.,
2007; Southall et al., 2007; G[ouml]tz et al., 2009). The degree of
effect is intrinsically related to the signal
[[Page 18357]]
characteristics, received level, distance from the source, and duration
of the sound exposure. In general, sudden, high level sounds can cause
hearing loss, as can longer exposures to lower level sounds. Temporary
or permanent loss of hearing will occur almost exclusively for noise
within an animal's hearing range. We first describe specific
manifestations of acoustic effects before providing discussion specific
to pile driving.
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., certain non-auditory
physical or physiological effects) only briefly as we do not expect
that there is a reasonable likelihood that pile driving may result in
such effects (see below for further discussion). Potential effects from
impulsive sound sources can range in severity from effects such as
behavioral disturbance or tactile perception to physical discomfort,
slight injury of the internal organs and the auditory system, or
mortality (Yelverton et al., 1973). Non-auditory physiological effects
or injuries that theoretically might occur in marine mammals exposed to
high level underwater sound or as a secondary effect of extreme
behavioral reactions (e.g., change in dive profile as a result of an
avoidance reaction) caused by exposure to sound include neurological
effects, bubble formation, resonance effects, and other types of organ
or tissue damage (Cox et al., 2006; Southall et al., 2007; Zimmer and
Tyack, 2007; Tal et al., 2015). The construction activities considered
here do not involve the use of devices such as explosives or mid-
frequency tactical sonar that are associated with these types of
effects.
Threshold Shift--Marine mammals exposed to high-intensity sound, or
to lower-intensity sound for prolonged periods, can experience hearing
threshold shift (TS), which is the loss of hearing sensitivity at
certain frequency ranges (Finneran, 2015). TS can be permanent (PTS),
in which case the loss of hearing sensitivity is not fully recoverable,
or temporary (TTS), in which case the animal's hearing threshold would
recover over time (Southall et al., 2007). Repeated sound exposure that
leads to TTS could cause PTS. In severe cases of PTS, there can be
total or partial deafness, while in most cases the animal has an
impaired ability to hear sounds in specific frequency ranges (Kryter,
1985).
When PTS occurs, there is physical damage to the sound receptors in
the ear (i.e., tissue damage), whereas TTS represents primarily tissue
fatigue and is reversible (Southall et al., 2007). In addition, other
investigators have suggested that TTS is within the normal bounds of
physiological variability and tolerance and does not represent physical
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to
constitute auditory injury.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above (a 40-dB threshold shift approximates PTS onset;
e.g., Kryter et al., 1966; Miller, 1974) that inducing mild TTS (a 6-dB
threshold shift approximates TTS onset; e.g., Southall et al., 2007).
Based on data from terrestrial mammals, a precautionary assumption is
that the PTS thresholds for impulse sounds (such as impact pile driving
pulses as received close to the source) are at least 6 dB higher than
the TTS threshold on a peak-pressure basis and PTS cumulative sound
exposure level thresholds are 15 to 20 dB higher than TTS cumulative
sound exposure level thresholds (Southall et al., 2007). Given the
higher level of sound or longer exposure duration necessary to cause
PTS as compared with TTS, it is considerably less likely that PTS could
occur.
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. Few data
on sound levels and durations necessary to elicit mild TTS have been
obtained for marine mammals.
Marine mammal hearing plays a critical role in communication with
conspecifics, and interpretation of environmental cues for purposes
such as predator avoidance and prey capture. 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. 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 occurs during a time 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.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis))
and three species of pinnipeds (northern elephant seal (Mirounga
angustirostris), harbor seal, and California sea lion (Zalophus
californianus)) 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. There are no data 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 NMFS (2018).
Behavioral Effects--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
[[Page 18358]]
behavioral activities, and more sustained and/or potentially severe
reactions, such as displacement from or abandonment of high-quality
habitat. 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). 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, 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 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). However,
many delphinids approach low-frequency airgun source vessels with no
apparent discomfort or obvious behavioral change (e.g., Barkaszi et
al., 2012), indicating the importance of frequency output in relation
to the species' hearing sensitivity.
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, 2013b). 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 determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et
al., 2007; Gailey et al., 2016).
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., 2007). 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
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from airgun 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;
[[Page 18359]]
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 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).
Auditory Masking--Sound can disrupt behavior through masking, or
interfering with, an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance, navigation) (Richardson et al., 1995; Erbe et al.,
2016). 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.,
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.
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore,
[[Page 18360]]
when the coincident (masking) sound is man-made, it may be considered
harassment if disrupting behavioral patterns. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which occurs during the sound exposure. Because masking
(without resulting in TS) is not associated with abnormal physiological
function, it is not considered a physiological effect, but rather a
potential behavioral effect.
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., 2007; 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.
Potential Effects of the Specified Activity--As described
previously (see ``Description of Active Acoustic Sound Sources''),
Vineyard Wind proposes to conduct pile driving in the WDA. The effects
of pile driving on marine mammals are dependent on several factors,
including the size, type, and depth of the animal; the depth,
intensity, and duration of the pile driving sound; the depth of the
water column; the substrate of the habitat; the distance between the
pile and the animal; and the sound propagation properties of the
environment.
Noise generated by impact pile driving consists of regular, pulsed
sounds of short duration. These pulsed sounds are typically high energy
with fast rise times. Exposure to these sounds may result in harassment
depending on proximity to the sound source and a variety of
environmental and biological conditions (Dahl et al., 2015; Nedwell et
al., 2007). Illingworth & Rodkin (2007) measured an unattenuated sound
pressure within 10 m (33 ft) at a peak of 220 dB re 1 [mu]Pa for a 2.4
m (96 in) steel pile driven by an impact hammer, and Brandt et al.
(2011) found that for a pile driven in a Danish wind farm in the North
Sea, the peak pressure at 720 m (0.4 nm) from the source was 196 dB re
1 [mu]Pa. Studies of underwater sound from pile driving finds that most
of the acoustic energy is below one to two kHz, with broadband sound
energy near the source (40 Hz to >40 kHz) and only low-frequency energy
(<~400 Hz) at longer ranges (Bailey et al., 2010; Erbe, 2009;
Illingworth & Rodkin, 2007). There is typically a decrease in sound
pressure and an increase in pulse duration the greater the distance
from the noise source (Bailey et al., 2010). Maximum noise levels from
pile driving usually occur during the last stage of driving each pile
where the highest hammer energy levels are used (Betke, 2008).
Available information on impacts to marine mammals from pile
driving associated with offshore wind is limited to information on
harbor porpoises and seals, as the vast majority of this research has
occurred at European offshore wind projects where large whales are
uncommon. Harbor porpoises, one of the most behaviorally sensitive
cetaceans, have received particular attention in European waters due to
their protection under the European Union Habitats Directive (EU 1992,
Annex IV) and the threats they face as a result of fisheries bycatch.
Brandt et al. (2016) summarized the effects of the construction of
eight offshore wind projects within the German North Sea between 2009
and 2013 on harbor porpoises, combining PAM data from 2010-2013 and
aerial surveys from 2009-2013 with data on noise levels associated with
pile driving. Baseline analyses were conducted initially to identify
the seasonal distribution of porpoises in different geographic
subareas. Results of the analysis revealed significant declines in
porpoise detections during pile driving when compared to 25-48 hours
before pile driving began, with the magnitude of decline during pile
driving clearly decreasing with increasing distances to the
construction site. During the majority of projects significant declines
in detections (by at least 20 percent) were found within at least 5-10
km of the pile driving site, with declines at up to 20-30 km of the
pile driving site documented in some cases. Such differences between
responses at the different projects could not be explained by
differences in noise levels alone and may be associated instead with a
relatively high quality of feeding habitat and a lower motivation of
porpoises to leave the noise impacted area in certain locations, though
the authors were unable to determine exact reasons for the apparent
differences. There were no indications for a population decline of
harbor porpoises over the five year study period based on analyses of
daily PAM data and aerial survey data at a larger scale (Brandt et al.,
2016). Despite extensive construction activities over the study period
and an increase in these activities over time, there was no long-term
negative trend in acoustic porpoise detections or densities within any
of the subareas studied. In some areas, PAM data even detected a
positive trend from 2010 to 2013. Even though clear negative short-term
effects (1-2 days in duration) of offshore wind farm construction were
found (based on acoustic porpoise detections), the authors found no
indication that harbor porpoises within the German Bight were
negatively affected by wind farm construction at the population level
(Brandt et al., 2016).
Monitoring of harbor porpoises before and after construction at the
Egmond aan Zee offshore wind project in the Dutch North Sea showed that
more porpoises were found in the wind project area compared to two
reference areas post-construction, leading the authors to conclude that
this effect was linked to the presence of the wind project, likely due
to increased food availability as well as the exclusion of fisheries
and reduced vessel traffic in the wind project (Lindeboom et al.,
2013). The available literature indicates harbor porpoise avoidance of
pile driving at offshore wind projects has occurred during the
construction phase.
[[Page 18361]]
Where long term monitoring has been conducted, harbor porpoises have
re-populated the wind farm areas after construction ceased, with the
time it takes to re-populate the area varying somewhat, indicating that
while there are short-term impacts to porpoises during construction,
population-level or long-term impacts are unlikely.
Harbor seals are also a particularly behaviorally sensitive
species. A harbor seal telemetry study off the East coast of England
found that seal abundance was significantly reduced up to 25 km from
WTG pile driving during construction, but found no significant
displacement resulted from construction overall as the seals'
distribution was consistent with the non-piling scenario within two
hours of cessation of pile driving (Russell et al., 2016). Based on two
years of monitoring at the Egmond aan Zee offshore wind project in the
Dutch North Sea, satellite telemetry, while inconclusive, seemed to
show that harbor seals avoided an area up to 40 km from the
construction site during pile driving, though the seals were documented
inside the wind farm after construction ended, indicating any avoidance
was temporary (Lindeboom et al., 2013).
Taken as a whole, the available literature suggests harbor seals
and harbor porpoises have shown avoidance of pile driving at offshore
wind projects during the construction phase in some instances, with the
duration of avoidance varying greatly, and with re-population of the
area generally occurring post-construction. The literature suggests
that marine mammal responses to pile driving in the offshore
environment are not predictable and may be context-dependent. It should
also be noted that the only studies available on marine mammal
responses to offshore wind-related pile driving have focused on species
which are known to be more behaviorally sensitive to auditory stimuli
than the other species that occur in the project area. Therefore, the
documented behavioral responses of harbor porpoises and harbor seals to
pile driving in Europe should be considered as a worst case scenario in
terms of the potential responses among all marine mammals to offshore
pile driving, and these responses cannot reliably predict the responses
that will occur in other species.
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). It is possible that the onset of pile
driving could result in temporary, short-term changes in an animal's
typical behavioral patterns and/or temporary 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. 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 lead to effects on growth, survival, or reproduction, such as
drastic changes in diving/surfacing patterns or significant habitat
abandonment are considered extremely unlikely in the case of the
proposed project, as it is expected that mitigation measures, including
clearance zones and soft start (described in detail below, see
``Proposed Mitigation Measures'') will minimize the potential for
marine mammals to be exposed to sound levels that would result in more
extreme behavioral responses. In addition, marine mammals in the
project area are expected to avoid any area that would be ensonified at
sound levels high enough for the potential to result in more severe
acute behavioral responses, as the offshore environment would allow
marine mammals the ability to freely move to other areas without
restriction.
In the case of pile driving, sound sources would be active for
relatively short durations, with relation to potential for masking. The
frequencies output by pile driving activity are lower than those used
by most species expected to be regularly present for communication or
foraging. Those species who would be more susceptible to masking at
these frequencies (LF cetaceans) use the area only seasonally. We
expect insignificant impacts from masking, and 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 impact pile driving, and which have already been taken
into account in the exposure analysis.
Anticipated Effects on Marine Mammal Habitat
The proposed activities would result in the placement of permanent
structures (i.e., WTGs) in the marine environment. Based on the best
available information, the long-term presence of the WTGs is not
expected to have negative impacts on habitats used by marine mammals,
and may ultimately have beneficial impacts on those habitats as a
result of increased presence of prey species in the project area due to
the WTGs acting as artificial reefs (Russell et al., 2014). The
proposed activities may have potential short-term impacts to food
sources such as forage fish. The proposed activities could also affect
acoustic habitat (see masking discussion above), but meaningful impacts
are unlikely. There are no known foraging hotspots, or other ocean
bottom structures of significant biological importance to marine
mammals present in 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. The most likely impact to marine mammal habitat
occurs from pile driving effects on likely marine mammal prey (e.g.,
fish). Impacts to the immediate substrate during installation of piles
are anticipated, but these would be limited to minor, temporary
suspension of sediments, which could impact water quality and
visibility for a short amount of time, but which would not be expected
to have any effects on individual marine mammals. Impacts to substrate
are therefore not discussed further.
Effects to Prey--Sound may affect marine mammals through impacts on
the abundance, behavior, or distribution of prey species (e.g.,
crustaceans, cephalopods, fish, zooplankton). Marine mammal prey varies
by species, season, and location and, for some, is not well documented.
Here, we describe studies regarding the effects of noise on known
marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and
[[Page 18362]]
detect the motion of surrounding water (Fay et al., 2008). The
potential effects of noise on fishes depends on the overlapping
frequency range, distance from the sound source, water depth of
exposure, and species-specific hearing sensitivity, anatomy, and
physiology. Key impacts to fishes may include behavioral responses,
hearing damage, barotrauma (pressure-related injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish, 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). Several studies have demonstrated that impulse sounds might
affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017). However, some
studies have shown no or slight reaction to impulse sounds (e.g., Pena
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott
et al., 2012). More commonly, though, the impacts of noise on fish are
temporary.
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al., (2012a) showed that a TTS of 4-6 dB was recoverable within 24
hours for one species. Impacts would be most severe when the individual
fish is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al., 2012b; Casper et al., 2013).
The most likely impact to fish from pile driving activities at the
project areas would be temporary behavioral avoidance of the area. The
duration of fish avoidance of an 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 due to the expected
short daily duration of individual pile driving events and the
relatively small areas being affected.
The area likely impacted by the activities is relatively small
compared to the available habitat in shelf waters in the region. 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. Based on the information discussed herein, 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 noise
from pile driving has the potential to result in disruption of
behavioral patterns for individual marine mammals. There is also some
potential for auditory injury (Level A harassment) to result. 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 harassment) or to incur PTS
of some degree (equated to Level A harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source (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 160 dB re 1 [mu]Pa (rms)
for impulsive and/or intermittent sources (e.g., impact pile driving).
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on
[[Page 18363]]
Marine Mammal Hearing (Version 2.0) (Technical Guidance, 2018)
identifies dual criteria to assess auditory injury (Level A harassment)
to five different marine mammal groups (based on hearing sensitivity)
as a result of exposure to noise from two different types of sources
(impulsive or non-impulsive). The components of Vineyard Wind's
proposed activity that may result in the take of marine mammals include
the use of impulsive sources.
These thresholds are provided in Table 4. The references, analysis,
and methodology used in the development of the thresholds are described
in NMFS 2018 Technical Guidance, which may be accessed at:
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds \*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
As described above, Vineyard Wind is proposing to install up to 100
WTGs and up to two ESPs in the WDA (i.e., a maximum of 102
foundations). Two types of foundations may be used in the construction
of the project and were therefore considered in the acoustic modeling
study conducted to estimate the potential number of marine mammal
exposures above relevant harassment thresholds: Monopile foundations
varying in size with a maximum of 10.3 m (33.8 ft) diameter piles and
jacket-style foundations using three or four 3 m (9.8 ft) diameter
(pin) piles per foundation.
As described above, Vineyard Wind has incorporated more than one
design scenario in their planning of the project. This approach, called
the ``design envelope'' concept, allows for flexibility on the part of
the developer, in recognition of the fact that offshore wind technology
and installation techniques are constantly evolving and exact
specifications of the project are not yet certain as of the publishing
of this document. Variables that are not yet certain include the
number, size, and configuration of WTGs and ESPs and their foundations,
and the number of foundations that may be installed per day (a maximum
of two foundations would be installed per day).
In recognition of the need to ensure that the range of potential
impacts to marine mammals from the various potential scenarios within
the design envelope are accounted for, potential design scenarios were
modeled separately in order to conservatively assess the impacts of
each scenario. The two installation scenarios modeled are shown in
Table 5 and consist of:
(1) The ``maximum design'' consisting of ninety 10.3 m (33.8 ft)
WTG monopile foundations, 10 jacket foundations (i.e., 40 jacket
piles), and two jacket foundations for ESPs (i.e., eight jacket piles),
and
(2) The ``most likely design'' consisting of one hundred 10.3 m
(33.8 ft) WTG monopile foundations and two jacket foundations for ESPs
(i.e., eight jacket piles).
Table 5--Potential Construction Scenarios Modeled
--------------------------------------------------------------------------------------------------------------------------------------------------------
WTG monopiles WTG jacket ESP jacket
(pile size: foundations foundations Total number of Total number of
Design scenario 10.3 m (33.8 (pile size: 3 m (pile size: 3 m piles installation
ft)) (9.8 ft)) (9.8 ft)) locations
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum design..................................................... 90 10 2 138 102
Most likely design................................................. 100 0 2 108 102
--------------------------------------------------------------------------------------------------------------------------------------------------------
As Vineyard Wind may install either one or two monopiles per day,
both the ``maximum design'' and ``most likely design'' scenarios were
modeled assuming the installation of one foundation per day and two
foundations per day distributed across the same calendar period. No
more than one jacket would be installed per day thus one jacket
foundation per day (four piles) was assumed for both scenarios. No
concurrent pile driving (i.e., driving of more than one pile at a time)
would occur and therefore concurrent driving was not modeled. The pile-
driving
[[Page 18364]]
schedules for modeling were created based on the number of expected
suitable weather days available per month (based on weather criteria
determined by Vineyard Wind) in which pile driving may occur to better
understand when the majority of pile driving is likely to occur
throughout the year. The number of suitable weather days per month was
obtained from historical weather data. The modeled pile-driving
schedule for the Maximum Design scenario is shown in Table 2 of the IHA
application.
Piles for monopile foundations would be constructed for specific
locations with maximum diameters ranging from ~8 m (26.2 ft) up to
~10.3 m (33.8 ft) and an expected median diameter of ~9 m (29.5 ft).
The 10.3 m (33.8 ft) monopile foundation is the largest potential pile
diameter proposed for the project; while a smaller diameter pile may
ultimately end up being installed, 10.3 m represents the largest
potential diameter and was therefore used in modeling of monopile
installation to be conservative. Jacket foundations each require the
installation of three to four jacket securing piles, known as jacket
piles, of ~3 m (9.8 ft) diameter. All modeling assumed 10.3 m piles
would be used for monopiles and 3 m piles would be used for jacket
foundations (other specifications associated with monopiles and jacket
piles are shown in Table 1 above and Figures 2 and 3 in the IHA
application).
Representative hammering schedules of increasing hammer energy with
increasing penetration depth were modeled, resulting in, generally,
higher intensity sound fields as the hammer energy and penetration
increases. For both monopile and jacket structure models, the piles
were assumed to be vertical and driven to a penetration depth of 30 m
and 45 m, respectively. While pile penetrations across the site would
vary, these values were chosen as reasonable penetration depths. The
estimated number of strikes required to drive piles to completion were
obtained from drivability studies provided by Vineyard Wind. All
acoustic modeling was performed assuming that only one pile is driven
at a time.
Additional modeling assumptions for the monopiles were as follows:
1,030 cm steel cylindrical piling with wall thickness of
10 cm.
Impact pile driver: IHC S-4000 (4000 kJ rated energy; 1977
kN ram weight).
Helmet weight: 3234 kN.
Additional modeling assumptions for the jacket pile are as follows:
300 cm steel cylindrical pilings with wall thickness of 5
cm.
Impact pile driver: IHC S-2500 (2500 kJ rated energy; 1227
kN ram weight).
Helmet weight: 2401 kN.
Up to four jacket piles installed per day.
Sound fields produced during pile driving were modeled by first
characterizing the sound signal produced during pile driving using the
industry-standard GRLWEAP (wave equation analysis of pile driving)
model and JASCO Applied Sciences' (JASCO) Pile Driving Source Model
(PDSM).
Underwater sound propagation (i.e., transmission loss) as a
function of range from each source was modeled using JASCO's Marine
Operations Noise Model (MONM) for multiple propagation radials centered
at the source to yield 3D transmission loss fields in the surrounding
area. The MONM computes received per-pulse SEL for directional sources
at specified depths. MONM uses two separate models to estimate
transmission loss.
At frequencies less than 2 kHz, MONM computes acoustic propagation
via a wide-angle parabolic equation (PE) solution to the acoustic wave
equation based on a version of the U.S. Naval Research Laboratory's
Range-dependent Acoustic Model (RAM) modified to account for an elastic
seabed. MONM-RAM incorporates bathymetry, underwater sound speed as a
function of depth, and a geoacoustic profile based on seafloor
composition, and accounts for source horizontal directivity. The PE
method has been extensively benchmarked and is widely employed in the
underwater acoustics community, and MONM-RAM's predictions have been
validated against experimental data in several underwater acoustic
measurement programs conducted by JASCO. At frequencies greater than 2
kHz, MONM accounts for increased sound attenuation due to volume
absorption at higher frequencies with the widely used BELLHOP Gaussian
beam ray-trace propagation model. This component incorporates
bathymetry and underwater sound speed as a function of depth with a
simplified representation of the sea bottom, as subbottom layers have a
negligible influence on the propagation of acoustic waves with
frequencies above 1 kHz. MONM-BELLHOP accounts for horizontal
directivity of the source and vertical variation of the source beam
pattern. Both propagation models account for full exposure from a
direct acoustic wave, as well as exposure from acoustic wave
reflections and refractions (i.e., multi-path arrivals at the
receiver).
The sound field radiating from the pile was simulated using a
vertical array of point sources. Because sound itself is an oscillation
(vibration) of water particles, acoustic modeling of sound in the water
column is inherently an evaluation of vibration. For this study,
synthetic pressure waveforms were computed using FWRAM, which is
JASCO's acoustic propagation model capable of producing time-domain
waveforms.
Models are more efficient at estimating SEL than rms SPL.
Therefore, conversions may be necessary to derive the corresponding rms
SPL. Propagation was modeled for a subset of sites using a full-wave
RAM PE model (FWRAM), from which broadband SEL to SPL conversion
factors were calculated. The FWRAM required intensive calculation for
each site, thus a representative subset of modeling sites were used to
develop azimuth-, range-, and depth-dependent conversion factors. These
conversion factors were used to calculate the broadband rms SPL from
the broadband SEL prediction.
Two locations within the WDA were selected to provide
representative propagation and sound fields for the project area (see
Table 6). The two locations were selected to span the region from
shallow to deep water and varying distances to dominant bathymetric
features (i.e., slope and shelf break). Water depth and environmental
characteristics (e.g., bottom-type) are similar throughout the WDA
(Vineyard Wind, 2016), and therefore minimal difference was found in
sound propagation results for the two sites (see Appendix A of the IHA
application for further detail).
Table 6--Locations Used in Propagation Modeling
--------------------------------------------------------------------------------------------------------------------------------------------------------
Location (UTM zone 19N)
Site -------------------------------- Water depth Sound sources modeled
Easting Northing (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
P1............................................. 382452 4548026 38 Monopile, Jacketed pile.
[[Page 18365]]
P2............................................. 365240 4542200 46 Monopile, Jacketed pile.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated pile driving schedules were used to calculate the SEL
sound fields at different points in time during pile driving. The pile
driving schedule for monopiles is shown in Tables A-3 and A-4 in the
IHA application. For each hammer energy level, the pile penetration is
expected to be 20% of the total depth.
The sound propagation modeling incorporated site-specific
environmental data that describes the bathymetry, sound speed in the
water column, and seabed geoacoustics in the construction area. Sound
level estimates are calculated from three-dimensional sound fields and
then collapsed over depth to find the ranges to predetermined threshold
levels (see the IHA application; Appendix A.3.2). Contour maps (see the
IHA application; Appendix A.14) show the planar distribution of the
limits of the areas affected by levels that are higher than the
specific sound level thresholds.
The modeled source spectra are provided in Figures 11 and 12 of the
IHA application. For both pile diameters, the dominant energy is below
100 Hz. The source spectra of the 10.3 m (33.8 ft) pile installation
contain more energy at lower frequencies than for the smaller 3 m (9.8
ft) piles. Please see Appendix A of the IHA application for further
details on the modeling methodology.
Noise attenuation systems, such as bubble curtains, are sometimes
used to decrease the sound levels radiated from a source. Bubbles
create a local impedance change that acts as a barrier to sound
transmission. The size of the bubbles determines their effective
frequency band, with larger bubbles needed for lower frequencies. There
are a variety of bubble curtain systems, confined or unconfined
bubbles, and some with encapsulated bubbles or panels. Attenuation
levels also vary by type of system, frequency band, and location. Small
bubble curtains have been measured to reduce sound levels but effective
attenuation is highly dependent on depth of water, current, and
configuration and operation of the curtain (Austin, Denes, MacDonnell,
& Warner, 2016; Koschinski & L[uuml]demann, 2013). Bubble curtains vary
in terms of the sizes of the bubbles and those with larger bubbles tend
to perform a bit better and more reliably, particularly when deployed
with two separate rings (Bellmann, 2014; Koschinski & L[uuml]demann,
2013; Nehls, Rose, Diederichs, Bellmann, & Pehlke, 2016).
Encapsulated bubble systems (e.g., Hydro Sound Dampers (HSDs)), can
be effective within their targeted frequency ranges, e.g., 100-800 Hz,
and when used in conjunction with a bubble curtain appear to create the
greatest attenuation. The literature presents a wide array of observed
attenuation results for bubble curtains. The variability in attenuation
levels is the result of variation in design, as well as differences in
site conditions and difficulty in properly installing and operating in-
water attenuation devices. A California Department of Transportation
(CalTrans) study tested several systems and found that the best
attenuation systems resulted in 10-15 dB of attenuation (Buehler et
al., 2015). Similarly, D[auml]hne, Tougaard, Carstensen, Rose, and
Nabe-Nielsen (2017) found that single bubble curtains that reduced
sound levels by 7 to 10 dB reduced the overall sound level by ~12 dB
when combined as a double bubble curtain for 6 m steel monopiles in the
North Sea. In modeling the sound fields for the proposed project,
hypothetical broadband attenuation levels of 6 dB and 12 dB were
modeled to gauge the effects on the ranges to thresholds given these
levels of attenuation.
The updated acoustic thresholds for impulsive sounds (such as pile
driving) contained in the Technical Guidance (NMFS, 2018) were
presented as dual metric acoustic thresholds using both
SELcum and peak sound pressure level metrics. As dual
metrics, NMFS considers onset of PTS (Level A harassment) to have
occurred when either one of the two metrics is exceeded (i.e., metric
resulting in the largest isopleth). The SELcum metric
considers both level and duration of exposure, as well as auditory
weighting functions by marine mammal hearing group.
Table 7 shows the modeled radial distances to the dual Level A
harassment thresholds using NMFS (2018) frequency weighting for marine
mammals, with 0, 6, and 12 dB sound attenuation incorporated. For the
peak level, the greatest distances expected are shown, typically
occurring at the highest hammer energies. The distances to SEL
thresholds were calculated using the hammer energy schedules for
driving one monopile or four jacket piles, as shown. The radial
distances shown in Table 7 are the maximum distances from the piles,
averaged between the two modeled locations.
Table 7--Radial Distances (m) to Level A Harassment Thresholds for Each Foundation Type With 0, 6, and 12 dB Sound Attenuation Incorporated
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment (peak) Level A harassment (SEL)
------------------------------------------------------------------------------------------------
Foundation type Hearing group 6 dB 12 dB 6 dB 12 dB
No attenuation attenuation attenuation No attenuation attenuation attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
10.3 m (33.8 ft) monopile......... LFC 34 17 8.5 5,443 3,191 1,599
MFC 10 5 2.5 56 43 0
HFC 235 119 49 101 71 71
PPW 38 19 10 450 153 71
Four, 3 m (9.8 ft) jacket piles... LFC 7.5 4 2.5 12,975 7,253 3,796
MFC 2.5 1 0.5 71 71 56
HFC 51 26 13.5 1,389 564 121
[[Page 18366]]
PPW 9 5 2.5 2,423 977 269
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Radial distances were modeled at two different representative modeling locations as described above. Distances shown represent the average of the two
modeled locations.
Table 8 shows the modeled radial distances to the Level B
harassment threshold with no attenuation, 6 dB and 12 dB sound
attenuation incorporated. Acoustic propagation was modeled at two
representative sites in the WDA as described above. The radial
distances shown in Table 8 are the maximum distance to the Level B
harassment threshold from the piles, averaged between the two modeled
locations, using the maximum hammer energy.
Table 8--Radial Distances (m) to the Level B Harassment Threshold
----------------------------------------------------------------------------------------------------------------
6 dB 12 dB
Foundation type No attenuation attenuation attenuation
----------------------------------------------------------------------------------------------------------------
10.3 m (33.8 ft) monopile....................................... 6,316 4,121 2,739
Four, 3 m (9.8 ft) jacket piles................................. 4,104 3,220 2,177
----------------------------------------------------------------------------------------------------------------
Please see Appendix A of the IHA application for further detail on
the acoustic modeling methodology.
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
The best available information regarding marine mammal densities in
the project area is provided by habitat-based density models produced
by the Duke University Marine Geospatial Ecology Laboratory (Roberts et
al., 2016, 2017, 2018). Density models were originally developed for
all cetacean taxa in the U.S. Atlantic (Roberts et al., 2016); more
information, including the model results and supplementary information
for each model, is available at seamap.env.duke.edu/models/Duke-EC-GOM-2015/. In subsequent years, certain models have been updated on the
basis of additional data as well as certain methodological
improvements. Although these updated models (and a newly developed seal
density model) are not currently publicly available, our evaluation of
the changes leads to a conclusion that these represent the best
scientific evidence available. Marine mammal density estimates in the
WDA (animals/km\2\) were obtained using these model results (Roberts et
al., 2016, 2017, 2018). As noted, the updated models incorporate
additional sighting data, including sightings from the NOAA Atlantic
Marine Assessment Program for Protected Species (AMAPPS) surveys from
2010-2014, which included some aerial surveys over the RI/MA & MA WEAs
(NEFSC & SEFSC, 2011b, 2012, 2014a, 2014b, 2015, 2016).
Mean monthly densities for all animals were calculated using a 13
km (8 mi) buffered polygon around the WDA perimeter and overlaying it
on the density maps from Roberts et al. (2016, 2017, 2018). Please see
Figure 13 in the IHA application for an example of a density map
showing Roberts et al. (2016, 2017, 2018) density grid cells with a 13
km buffer overlaid on a map of the WDA. The 13 km (8 mi) buffer is
conservative as it encompasses and extends beyond the estimated
distances to the isopleth corresponding to the Level B harassment (with
no attenuation, as well as with 6 dB and 12 dB sound attenuation) for
all hearing groups using the unweighted threshold of 160 dB re 1 [mu]Pa
(rms) (Table 8). The 13 km buffer incorporates the maximum area around
the WDA with the potential to result in behavioral disturbance for the
10.3 m (33.8 ft) monopile installation using (Wood, Southall, & Tollit,
2012) threshold criteria.
The mean density for each month was determined by calculating the
unweighted mean of all 10 x 10 km (6.2 x 6.2 mi) grid cells partially
or fully within the buffer zone polygon. Densities were computed for
the months of May to December to coincide with planned pile driving
activities (as described above, no pile driving would occur from
January through April). In cases where monthly densities were
unavailable, annual mean densities (e.g., pilot whales) and seasonal
mean densities (e.g., all seals) were used instead. Table 9 shows the
monthly marine mammal density estimates for each species incorporated
in the exposure modeling analysis.
Table 9--Monthly Marine Mammal Density Estimates for Each Species Used in the Exposure Modeling Analysis
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Monthly densities (animals/100 km2) \1\ Annual May to
--------------------------------------------------------------------------------------------------------------------- Dec
Species --------
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean Mean
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale......................................................... 0.151 0.115 0.122 0.234 0.268 0.276 0.26 0.248 0.197 0.121 0.12 0.131 0.187 0.203
Humpback whale.................................................... 0.033 0.018 0.034 0.204 0.138 0.139 0.199 0.109 0.333 0.237 0.078 0.049 0.131 0.16
Minke whale....................................................... 0.052 0.064 0.063 0.136 0.191 0.171 0.064 0.051 0.048 0.045 0.026 0.037 0.079 0.079
North Atlantic right whale........................................ 0.205 0.309 0.543 0.582 0.287 0.308 0.002 0.002 0.006 0.001 0.001 0.267 0.209 0.109
Sei whale......................................................... 0.001 0.002 0.001 0.033 0.029 0.012 0.003 0.002 0.003 0.001 0.002 0.001 0.007 0.007
Atlantic white sided dolphin...................................... 1.935 0.972 1.077 2.088 4.059 3.742 2.801 1.892 1.558 1.95 2.208 3.281 2.297 2.686
[[Page 18367]]
Bottlenose dolphin................................................ 0.382 0.011 0.007 0.497 0.726 2.199 5.072 3.603 4.417 4.46 2.136 1.216 2.061 2.979
Pilot whales...................................................... 0.555 0.555 0.555 0.555 0.555 0.555 0.555 0.555 0.555 0.555 0.555 0.555 0.555 0.555
Risso's dolphin................................................... 0.006 0.003 0.001 0.001 0.005 0.005 0.01 0.02 0.016 0.006 0.013 0.018 0.009 0.012
Short beaked dolphin.............................................. 7.734 1.26 0.591 1.613 3.093 3.153 3.569 6.958 12.2 12.727 9.321 16.831 6.588 8.482
Sperm whale *..................................................... 0.001 0.001 0.001 0.001 0.003 0.006 0.029 0.033 0.012 0.012 0.008 0.001 0.009 0.013
Harbor porpoise................................................... 3.939 6.025 12.302 6.959 3.904 1.332 0.91 0.784 0.717 0.968 2.609 2.686 3.595 1.739
Gray seal \2\..................................................... 6.844 8.291 8.621 15.17 19.123 3.072 0.645 0.372 0.482 0.687 0.778 3.506 5.633 3.583
Harbor seal \2\................................................... 6.844 8.291 8.621 15.17 19.123 3.072 0.645 0.372 0.482 0.687 0.778 3.506 5.633 3.583
Harp seal \2\..................................................... 6.844 8.291 8.621 15.17 19.123 3.072 0.645 0.372 0.482 0.687 0.778 3.506 5.633 3.583
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1 Density estimates are from habitat-based density modeling of the entire Atlantic EEZ from Roberts et al. (2016, 2017, 2018).
2 All seal species are grouped together in the density models presented by Roberts et al. (2018).
JASCO's Animal Simulation Model Including Noise Exposure (JASMINE)
animal movement model was used to predict the probability of marine
mammal exposure to project-related sound. Sound exposure models like
JASMINE use simulated animals (also known as ``animats'') to forecast
behaviors of animals in new situations and locations based on
previously documented behaviors of those animals. The predicted 3D
sound fields (i.e., the output of the acoustic modeling process
described earlier) are sampled by animats using movement rules derived
from animal observations. The output of the simulation is the exposure
history for each animat within the simulation.
The precise location of animals (and their pathways) are not known
prior to a project, therefore a repeated random sampling technique
(Monte Carlo) is used to estimate exposure probability with many
animats and randomized starting positions. The probability of an animat
starting out in or transitioning into a given behavioral state can be
defined in terms of the animat's current behavioral state, depth, and
the time of day. In addition, each travel parameter and behavioral
state has a termination function that governs how long the parameter
value or overall behavioral state persists in the simulation.
The output of the simulation is the exposure history for each
animat within the simulation, and the combined history of all animats
gives a probability density function of exposure during the project.
Scaling the probability density function by the real-world density of
animals (Table 9) results in the mean number of animals expected to be
exposed over the duration of the project. Due to the probabilistic
nature of the process, fractions of animals may be predicted to exceed
threshold. If, for example, 0.1 animals are predicted to exceed
threshold in the model, that is interpreted as a 10% chance that one
animal will exceed a relevant threshold during the project, or
equivalently, if the simulation were re-run ten times, one of the ten
simulations would result in an animal exceeding the threshold.
Similarly, a mean number prediction of 33.11 animals can be interpreted
as re-running the simulation where the number of animals exceeding the
threshold may differ in each simulation but the mean number of animals
over all of the simulations is 33.11. A portion of an animal cannot be
taken during a project, so it is common practice to round mean number
animal exposure values to integers using standard rounding methods.
However, for low-probability events it is more precise to provide the
actual values. For this reason mean number values are not rounded.
Sound fields were input into the JASMINE model and animats were
programmed based on the best available information to ``behave'' in
ways that reflect the behaviors of the 15 marine mammal species
expected to occur in the project area during the proposed activity. The
various parameters for forecasting realistic marine mammal behaviors
(e.g., diving, foraging, surface times, etc.) are determined based on
the available literature (e.g., tagging studies); when literature on
these behaviors was not available for a particular species, it was
extrapolated from a similar species for which behaviors would be
expected to be similar to the species of interest. See Appendix B of
the IHA application for a description of the species that were used as
proxies when data on a particular species was not available. The
parameters used in JASMINE describe animal movement in both the
vertical and horizontal planes. The parameters relating to travel in
these two planes are briefly described below:
Travel Sub-Models
Direction--determines an animat's choice of direction in
the horizontal plane. Sub-models are available for determining the
heading of animats, allowing for movement to range from strongly biased
to undirected. A random walk model can be used for behaviors with no
directional preference, such as feeding and playing. A directional bias
can also be incorporated in the random walk for use in situations where
animals have a preferred absolute direction, such as migration.
Travel rate--defines an animat's rate of travel in the
horizontal plane. When combined with vertical speed and dive depth, the
dive profile of the animat is produced.
Dive Sub-Models
Ascent rate--defines an animat's rate of travel in the
vertical plane during the ascent portion of a dive.
Descent rate--defines an animat's rate of travel in the
vertical plane during the descent portion of a dive.
Depth--defines an animat's maximum dive depth.
Bottom following--determines whether an animat returns to
the surface once reaching the ocean floor, or whether it follows the
contours of the bathymetry.
Reversals--determines whether multiple vertical excursions
occur once an animat reaches the maximum dive depth. This behavior is
used to emulate the foraging behavior of some marine mammal species at
depth. Reversal-specific ascent and descent rates may be specified.
Surface interval--determines the duration an animat spends
at, or near, the surface before diving again.
An individual animat's received sound exposure levels are summed
over a specified duration, such as 24 hours, to determine its total
received energy, and then compared to the threshold criteria described
above. As JASMINE modeling includes the movement of animats both within
as well as in and out of the modeled ensonified area,
[[Page 18368]]
some animats enter and depart the modeled ensonified area within a
modeled 24 hour period; however, it is important to note that the model
accounts for the acoustic energy that an animat accumulates even if
that animat departs the ensonified area prior to the full 24 hours
(i.e., even if the animat departs prior to a full 24 hour modeled
period, if that animat accumulated enough acoustic energy to be taken,
it is accounted for in the take estimate). Also note that animal
aversion was not incorporated into the Jasmine model runs that were the
basis for the take estimate for any species. See Figure 14 in the IHA
application for a depiction of animats in an environment with a moving
sound field. See Appendix B of the IHA application for more details on
the JASMINE modeling methodology, including the literature sources used
for the parameters that were input in JASMINE to describe animal
movement for each species that is expected to occur in the project
area.
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate. The following steps
were performed to estimate the potential numbers of marine mammal
exposures above Level A and Level B harassment thresholds as a result
of the proposed activity:
(1) The characteristics of the sound output from the proposed pile-
driving activities were modeled using the GRLWEAP (wave equation
analysis of pile driving) model and JASCO's PDSM;
(2) Acoustic propagation modeling was performed using JASCO's MONM
and FWRAM that combined the outputs of the source model with the
spatial and temporal environmental context (e.g., location,
oceanographic conditions, seabed type) to estimate sound fields;
(3) Animal movement modeling integrated the estimated sound fields
with species-typical behavioral parameters in the JASMINE model to
estimate received sound levels for the animals that may occur in the
operational area; and
(4) The number of potential exposures above Level A and Level B
harassment thresholds was calculated for each potential scenario within
the project design envelope.
As described above, two project design scenarios were modeled: The
``maximum design'' consisting of ninety 10.3 m (33.8 ft) WTG monopile
foundations, 10 jacket foundations, and two jacket foundations for
ESPs, and the ``most likely design'' consisting of one hundred 10.3 m
(33.8 ft) WTG monopile foundations and two jacket foundations for ESPs
(Table 5). Both of these design scenarios were also modeled with either
one or two monopile foundations installed per day. All scenarios were
modeled with both 6 dB sound attenuation and 12 dB sound attenuation
incorporated. Results of marine mammal exposure modeling of these
scenarios is shown in Tables 10-13. Note that while fractions of an
animal cannot be taken, these tables are meant simply to show the
modeled exposure numbers, versus the actual proposed take estimate.
Requested and proposed take numbers are shown below in Tables 14 and
15.
Table 10--Mean Numbers of Marine Mammals Estimated To Be Exposed Above Level A and Level B Harassment Thresholds During the Proposed Project Using the
Maximum Design Scenario and One Foundation Installed per Day
--------------------------------------------------------------------------------------------------------------------------------------------------------
6 dB attenuation 12 dB attenuation
------------------------------------------------------------------------------------------------
Species Level A Level A Level A Level A
harassment harassment Level B harassment harassment Level B
(peak) (SEL) harassment (peak) (SEL) harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin Whale.............................................. 0.1 4.13 33.11 0.02 0.29 21.78
Humpback Whale......................................... 0.03 9.01 30.1 0.01 1 19.66
Minke Whale............................................ 0.04 0.22 12.21 0 0.07 7.9
North Atlantic Right Whale............................. 0.03 1.36 13.25 0 0.09 8.74
Sei Whale.............................................. 0 0.14 1.09 0 0.01 0.74
Atlantic White-Sided Dolphin........................... 0 0 449.2 0 0 277.82
Bottlenose Dolphin..................................... 0 0 96.21 0 0 62.21
Pilot Whales........................................... 0 0 0 0 0 0
Risso's Dolphin........................................ 0 0 1.61 0 0 1.04
Common Dolphin......................................... 0.1 0 1059.97 0.1 0 703.81
Sperm Whale............................................ 0 0 0 0 0 0
Harbor Porpoise........................................ 4.23 0.17 150.13 1.54 0 91.96
Gray Seal.............................................. 0.11 0.3 196.4 0.04 0.07 118.06
Harbor Seal............................................ 0.36 0.21 214.04 0.33 0.07 136.33
Harp Seal.............................................. 0.73 0.87 217.35 0 0.04 132.91
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 11--Mean Numbers of Marine Mammals Estimated To Be Exposed Above Level A and Level B Harassment Thresholds During the Proposed Project Using the
Maximum Design Scenario and Two Foundations Installed per Day
--------------------------------------------------------------------------------------------------------------------------------------------------------
6 dB attenuation 12 dB attenuation
------------------------------------------------------------------------------------------------
Species Level A Level A Level A Level A
harassment harassment Level B harassment harassment Level B
(peak) (SEL) harassment (peak) (SEL) harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin Whale.............................................. 0.1 4.49 29.71 0 0.41 20.57
Humpback Whale......................................... 0.03 9.59 27.23 0 1.09 18.48
Minke Whale............................................ 0.03 0.23 11.52 0 0.05 7.76
North Atlantic Right Whale............................. 0.02 1.39 11.75 0.01 0.1 7.96
Sei Whale.............................................. 0 0.14 0.93 0 0.01 0.65
[[Page 18369]]
Atlantic White-Sided Dolphin........................... 0.13 0 428.23 0 0 272.67
Bottlenose Dolphin..................................... 0 0 67.71 0 0 43.87
Pilot Whales........................................... 0 0 0 0 0 0
Risso's Dolphin........................................ 0 0 1.38 0 0 0.95
Common Dolphin......................................... 0.44 0 897.91 0.1 0 622.78
Sperm Whale............................................ 0 0 0 0 0 0
Harbor Porpoise........................................ 4.23 0.17 125.23 1.85 0.06 82.28
Gray Seal.............................................. 0.29 0.47 145.2 0.04 0.25 96.41
Harbor Seal............................................ 1.01 0.86 164.48 0.16 0.39 110.25
Harp Seal.............................................. 0.38 0.53 162.03 0.17 0.04 108.19
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 12--Mean Numbers of Marine Mammals Estimated To Be Exposed Above Level A and Level B Harassment Thresholds During the Proposed Project Using the
Most Likely Scenario and One Foundation Installed per Day
--------------------------------------------------------------------------------------------------------------------------------------------------------
6 dB attenuation 12 dB attenuation
------------------------------------------------------------------------------------------------
Species Level A Level A Level A Level A
harassment harassment Level B harassment harassment Level B
(peak) (SEL) harassment (peak) (SEL) harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin Whale.............................................. 0.11 2.84 29.85 0.02 0.23 19.43
Humpback Whale......................................... 0.04 6.54 26.27 0.01 0.83 17.08
Minke Whale............................................ 0.04 0.13 10.28 0 0.06 6.77
North Atlantic Right Whale............................. 0.04 0.72 10.82 0 0.04 7.09
Sei Whale.............................................. 0 0.09 0.95 0 0.01 0.65
Atlantic White-Sided Dolphin........................... 0 0 380.82 0 0 236.77
Bottlenose Dolphin..................................... 0 0 98.56 0 0 64.19
Pilot Whales........................................... 0 0 0 0 0 0
Risso's Dolphin........................................ 0 0 1.48 0 0 0.94
Common Dolphin......................................... 0.01 0 941.41 0.01 0 617.01
Sperm Whale............................................ 0 0 0 0 0 0
Harbor Porpoise........................................ 3.86 0.14 134.88 1.38 0 80.89
Gray Seal.............................................. 0 0.01 176.92 0 0 104.6
Harbor Seal............................................ 0.34 0.01 191.06 0.34 0 120.64
Harp Seal.............................................. 0.72 0.72 193.65 0 0 116.13
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 13--Mean Numbers of Marine Mammals Estimated To Be Exposed Above Level A and Level B Harassment Thresholds During the Proposed Project Using the
Most Likely Scenario and Two Foundations Installed per Day
--------------------------------------------------------------------------------------------------------------------------------------------------------
6 dB attenuation 12 dB attenuation
------------------------------------------------------------------------------------------------
Species Level A Level A Level A Level A
harassment harassment Level B harassment harassment Level B
(peak) (SEL) harassment (peak) (SEL) harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin Whale.............................................. 0.11 3.24 26.07 0 0.36 18.08
Humpback Whale......................................... 0.04 7.18 23.09 0 0.93 15.77
Minke Whale............................................ 0.03 0.15 9.53 0 0.04 6.62
North Atlantic Right Whale............................. 0.02 0.76 9.21 0.01 0.06 6.25
Sei Whale.............................................. 0 0.09 0.78 0 0.01 0.55
Atlantic White-Sided Dolphin........................... 0.14 0 357.71 0 0 231.09
Bottlenose Dolphin..................................... 0 0 66.75 0 0 43.72
Pilot Whales........................................... 0 0 0 0 0 0
Risso's Dolphin........................................ 0 0 1.22 0 0 0.84
Common Dolphin......................................... 0.39 0 761.48 0.01 0 527.04
Sperm whale............................................ 0 0 0 0 0 0
Harbor Porpoise........................................ 3.86 0.14 107.61 1.72 0.07 70.29
Gray Seal.............................................. 0.19 0.19 123.97 0 0.18 82.23
Harbor Seal............................................ 1.01 0.68 139.82 0.17 0.34 93.67
Harp Seal.............................................. 0.36 0.36 136.45 0.18 0 90.56
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 18370]]
As shown in Tables 10-13, the greatest potential number of marine
mammal exposures above the Level B harassment threshold occurs under
the Maximum Design scenario with one monopile foundation installed per
day (Table 10) while the greatest potential number of marine mammal
exposures above the Level A harassment thresholds occurs under the
Maximum Design scenario with one monopile foundation installed per day.
With the inclusion of more jacket foundations, which would require more
piles and more overall pile driving, marine mammal exposure estimates
for the Maximum Design scenario (Tables 10 and 11) are higher than
under the Most Likely scenario (Tables 12 and 13). In all scenarios,
the maximum number of jacket foundations modeled per day was one (four
jacket piles). Modeling indicates that whether one monopile foundation
is installed per day or two makes little difference with respect to
estimated Level A harassment exposures; total exposures above the Level
A harassment threshold differed by less than one exposure over the
duration of the project, for each species. For exposures above the
Level B harassment threshold, exposure estimates for one monopile
foundation per day are somewhat higher than for two monopile
foundations per day. With two monopile foundations per day, there are
half as many days of pile driving so there is likewise a reduced number
of overall predicted Level B harassment exposures over the duration of
the project.
To be conservative, Vineyard Wind based their take request on the
Maximum Design scenario with one monopile installed per day. Vineyard
Wind also assumed that 12 dB sound attenuation can be achieved
consistently during the proposed activity, thus their take request was
based on modeled exposure numbers incorporating 12 dB effective
attenuation.
Although the exposure modeling indicated that no Level A harassment
takes are expected for several species (i.e., minke whale, sei whale,
and all small cetaceans and pinnipeds), Vineyard Wind requested Level A
harassment takes for most species as a precautionary measure, based on
the fact that shutdown of pile driving may not be technically feasible
once pile driving has begun, thus if a marine mammal were to enter the
Level A harassment zone after pile driving has commenced Vineyard Wind
may not be able to avoid that animal(s) being taken by Level A
harassment. Vineyard Wind requested Level A harassment takes for these
species based on mean group size for each respective species, based on
an assumption that if one group member were to be exposed, it is likely
that all animals in the same group would receive a similar exposure
level. Thus, for the species for which exposure modeling indicated less
than a group size would be taken (by either Level A or Level B
harassment), Vineyard Wind increased the value from the exposure
modeling results to equal one mean group size, rounded up to the
nearest integer, for species with predicted exposures of less than one
mean group size (with the exception of North Atlantic right whales, as
described below). Mean group sizes for species were derived from Kraus
et al. (2016), where available, as the best representation of expected
group sizes within the RI/MA & MA WEAs. These were calculated as the
number of individuals sighted, divided by the number of sightings
summed over the four seasons (from Tables 5 and 19 in Kraus et al.,
2016). Sightings for which species identification was considered either
definite or probable were used in the Kraus et al. (2016) data. For
species that were observed very rarely during the Kraus et al. (2016)
study (i.e., sperm whales and Risso's dolphins) or observed but not
analyzed (i.e., pinnipeds), data derived from AMAPPS surveys (Palka et
al., 2017) were used to evaluate mean group size. For sperm whales and
Risso's dolphins, the number of individuals divided by the number of
groups observed during 2010-2013 AMAPPS NE summer shipboard surveys and
NE aerial surveys during all seasons was used (Appendix I of Palka et
al., 2017). Though pinnipeds congregate in large numbers on land, at
sea they are generally foraging alone or in small groups. For harbor
and gray seals, Palka et al. (2017) report sightings of seals at sea
during 2010-2013 spring, summer, and fall NE AMAPPS aerial surveys.
Those sightings include both harbor seals and gray seals, as well as
unknown seals, and thus a single group size estimate was calculated for
these two species. Harp seals are occasionally recorded south of the
RI/MA & MA WEAs on Long Island, New York, and in the nearshore waters,
usually in groups of one or two individuals. During 2002-2018, the
Coastal Research and Education Society of Long Island (CRESLI) reported
seven sightings of harp seals (CRESLI, 2018). Five of these were of
single individuals and two were of two animals. Calculated group sizes
for all species are shown in Table 14.
Table 14--Mean Group Sizes of Marine Mammal Species Used To Estimate
Takes
------------------------------------------------------------------------
Mean
Species group
size
------------------------------------------------------------------------
Fin Whale...................................................... 1.8
Humpback Whale................................................. 2
Minke Whale.................................................... 1.2
North Atlantic Right Whale..................................... 2.4
Sei Whale...................................................... 1.6
Atlantic White-Sided Dolphin................................... 27.9
Common Bottlenose Dolphin...................................... 7.8
Pilot whale.................................................... 8.4
Risso's Dolphin................................................ 5.3
Short-Beaked Common Dolphin.................................... 34.9
Sperm Whale.................................................... 1.5
Harbor Porpoise................................................ 2.7
Gray Seal...................................................... 1.4
Harbor Seal.................................................... 1.4
Harp Seal...................................................... 1.3
------------------------------------------------------------------------
Vineyard Wind also requested Level B take numbers that differ from
the numbers modeled and were instead based on monitoring data from site
characterization surveys conducted at the same location. Vineyard Wind
reviewed monitoring data recorded during site characterization surveys
in the WDA from 2016-2018 and calculated a daily sighting rate
(individuals per day) for each species in each year, then multiplied
the maximum sighting rate from the three years by the number of pile
driving days under the Maximum Design scenario (i.e., 102 days). This
method assumes that the largest average group size for each species
observed during the three years of surveys may be present during piling
on each day. Vineyard Wind used this method for all species that were
documented by protected species observers (PSOs) during the 2016-2018
surveys. For sei whales, this approach resulted in the same number of
estimated Level B harassment takes as Level A harassment takes (two),
so to be conservative Vineyard Wind doubled the Level A harassment
value to arrive at the requested number of Level B harassment takes.
Risso's dolphins and harp seals were not documented by PSOs during
those surveys, so Vineyard Wind requested take based on two average
group sizes for those species. The Level B harassment take calculation
methodology described here resulted in higher take numbers than those
modeled (Table 10) for 10 out of 15 species expected to be taken.
We reviewed Vineyard Wind's take request and propose to authorize
take numbers that are slightly different than the numbers requested for
some species. Vineyard Wind's requested take numbers for Level A
harassment authorization are based on an
[[Page 18371]]
expectation that 12 dB sound attenuation will be effective during the
proposed activity. NMFS reviewed the CalTrans bubble curtain ``on and
off'' studies conducted in San Francisco Bay in 2003 and 2004. Based on
74 measurements (37 with the bubble curtain on and 37 with the bubble
curtain off) at both near (<100 m) and far (>100 m) distances, the
linear averaged received level reduction is 6 dB (CalTrans, 2015).
Nehls et al. (2016) reported that attenuation from use of a bubble
curtain during pile driving at the Borkum West II offshore wind farm in
the North Sea was between 10 dB and 17 dB (mean 14 dB) (peak).
Based on the best available information, we believe it reasonable
to assume some level of effective attenuation due to implementation of
noise attenuation during impact pile driving. Vineyard Wind has not
provided information regarding the attenuation system that will
ultimately be used during the proposed activity (e.g., what size
bubbles and in what configuration a bubble curtain would be used,
whether a double curtain will be employed, whether hydro-sound dampers,
noise abatement system, or some other alternate attenuation device will
be used, etc.) to support their conclusion that 12 dB effective
attenuation can be expected. In the absence of this information
regarding the attenuation system that will be used, and in
consideration of the available information on attenuation that has been
achieved during impact pile driving, we conservatively assume that 6 dB
sound attenuation will be achieved (although we do encourage Vineyard
Wind to target 12 dB noise attenuation). Therefore, where Vineyard
Wind's requested Level A take numbers were less than the Level A take
numbers modeled based on 6 dB noise attenuation (i.e., fin whale,
humpback whale and harbor porpoise) we propose to authorize higher
Level A take numbers than those requested. Vineyard Wind also requested
all take numbers based on the Maximum Design scenario with one pile
driven per day (Table 10); however, the Maximum Design scenario with
two piles driven per day resulted in slightly higher modeled takes by
Level A harassment (Table 11). We therefore propose to authorize takes
by Level A harassment based on the higher modeled take numbers.
Vineyard Wind's requested take numbers for Level B harassment
authorization are based on visual observation data recorded during the
company's site characterization surveys, as described above. In some
cases these numbers are lower than the Level B harassment exposure
numbers modeled based on marine mammal densities reported by Roberts et
al. (2016, 2017, 2018) with 6 dB sound attenuation applied (Table 10).
While we agree that Vineyard Wind's use of visual observation data as
the basis for Level B harassment take requests is generally sound, we
believe that, to be conservative, the higher of the two calculated take
numbers (i.e., take numbers based on available visual observation data,
or, based on modeled exposures above threshold) should be used to
estimate Level B exposures. Therefore, for species for which the Level
B harassment exposure numbers modeled based on marine mammal densities
reported by Roberts et al. (2016, 2017, 2018) with 6 dB sound
attenuation applied (Table 10) were higher than the take numbers based
on visual observation data (i.e., fin whale, bottlenose dolphin, harbor
porpoise, harbor seal and harp seal) we propose to authorize take
numbers based on those modeled using densities derived from Roberts et
al. (2016, 2017, 2018) with 6 dB sound attenuation applied.
For North Atlantic right whales, one exposure above the Level A
harassment threshold was modeled over the duration of the proposed
project based on the Maximum Design scenario and 6 dB effective
attenuation (Tables 10 and 11). However, Vineyard Wind has requested no
authorization for Level A harassment takes of North Atlantic right
whales, based on an expectation that any potential exposures above the
Level A harassment threshold will be avoided through enhanced
mitigation and monitoring measures proposed specifically to minimize
potential right whale exposures. We believe that, based on the enhanced
mitigation and monitoring measures proposed specifically for North
Atlantic right whales (described below, see ``Proposed Mitigation''),
including the proposed seasonal moratorium on construction from January
through April and enhanced clearance measures from November through
December and May 1 through May 14, any potential take of right whales
by Level A harassment will be avoided. Therefore, we do not propose to
authorize any takes of North Atlantic right whales by Level A
harassment.
Take numbers proposed for authorization are shown in Table 15.
Table 15--Total Numbers of Potential Incidental Take of Marine Mammals Proposed for Authorization and Proposed
Takes as a Percentage of Population
----------------------------------------------------------------------------------------------------------------
Total takes
Takes by Takes by Total takes as a
Species Level A Level B proposed for percentage of
harassment harassment authorization stock taken *
----------------------------------------------------------------------------------------------------------------
Fin whale....................................... 4 33 37 0.8
Humpback Whale.................................. 10 56 65 4.0
Minke Whale..................................... 2 98 100 4.7
North Atlantic Right Whale...................... 0 20 20 4.9
Sei Whale....................................... 2 4 6 0.8
Sperm whale..................................... 2 5 7 0.1
Atlantic White-Sided Dolphin.................... 28 1,107 1,135 3.1
Bottlenose Dolphin.............................. 8 96 104 0.1
Long-finned Pilot Whale......................... 9 91 100 0.5
Risso's Dolphin................................. 6 12 18 0.2
Common Dolphin.................................. 35 4,646 4,681 5.4
Harbor porpoise................................. 4 150 154 0.3
Gray seal....................................... 2 414 416 1.5
Harbor seal..................................... 2 214 216 0.3
[[Page 18372]]
Harp seal....................................... 2 217 219 0.0
----------------------------------------------------------------------------------------------------------------
* Calculations of percentage of stock taken are based on the best available abundance estimate as shown in Table
1. For North Atlantic right whales the best available abundance estimate is derived from the 2018 North
Atlantic Right Whale Consortium 2018 Annual Report Card (Pettis et al., 2018). For the pinniped species the
best available abundance estimates are derived from the most recent NMFS Stock Assessment Reports. For all
other species, the best available abundance estimates are derived from Roberts et al. (2016, 2017, 2018).
The take numbers we propose for authorization (Table 15) are
considered conservative for the following reasons:
Proposed take numbers are based on an assumption that all
installed monopiles would be 10.3 m in diameter, when some or all
monopiles ultimately installed may be smaller;
Proposed take numbers are based on an assumption that 102
foundations would be installed, when ultimately the total number
installed may be lower;
Proposed take numbers are based on a construction scenario
that includes up to 10 jacket foundations, when it is possible no more
than two jacket foundations may be installed;
Proposed Level A take numbers do not account for the
likelihood that marine mammals will avoid a stimulus when possible
before that stimulus reaches a level that would have the potential to
result in injury;
Proposed take numbers do not account for the effectiveness
of proposed mitigation and monitoring measures in reducing the number
of takes (with the exception of North Atlantic right whales, for which
proposed mitigation and monitoring measures are factored into the
proposed Level A harassment take number);
For 11 of 15 species, no Level A takes were predicted
based on modeling, however proposed Level A take numbers have been
conservatively increased from zero to mean group size for these
species.
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 and impact on
operations.
The mitigation strategies described below are consistent with those
required and successfully implemented under previous incidental take
authorizations issued in association with in-water construction
activities. Additional measures have also been incorporated to account
for the fact that the proposed construction activities would occur
offshore. Modeling was performed to estimate zones of influence (ZOI;
see ``Estimated Take''); these ZOI values were used to inform
mitigation measures for pile driving activities to minimize Level A
harassment and Level B harassment to the extent possible, while
providing estimates of the areas within which Level B harassment might
occur.
In addition to the specific measures described later in this
section, Vineyard Wind would conduct briefings for construction
supervisors and crews, the marine mammal and acoustic monitoring teams,
and Vineyard Wind staff prior to the start of all pile driving
activity, and when new personnel join the work, in order to explain
responsibilities, communication procedures, the marine mammal
monitoring protocol, and operational procedures.
Seasonal Restriction on Pile Driving
No pile driving activities would occur between January 1 through
April 30. This seasonal restriction would be established to minimize
the potential for North Atlantic right whales to be exposed to pile
driving noise. Based on the best available information (Kraus et al.,
2016; Roberts et al., 2017), the highest densities of right whales in
the project area are expected during the months of January through
April. This restriction would greatly reduce the potential for right
whale exposure to pile driving noise associated with the proposed
project.
Clearance Zones
Vineyard Wind would use PSOs to establish clearance zones around
the pile driving equipment to ensure these zones are clear of marine
mammals prior to the start of pile driving. The purpose of
``clearance'' of a particular zone is to prevent potential instances of
auditory injury and potential instances of more severe behavioral
disturbance as a result of exposure to pile driving noise (serious
injury or death are unlikely outcomes even in the absence of mitigation
measures) by delaying the activity before it begins if marine mammals
are detected within certain pre-defined distances of the pile driving
equipment. The primary goal in this case is to prevent auditory injury
(Level A harassment), and the proposed clearance zones are larger than
the modeled distances to the isopleths corresponding to Level A
harassment (based on peak SPL) for all marine
[[Page 18373]]
mammal functional hearing groups, assuming an effective 6 dB
attenuation of pile driving noise. Proposed clearance zones would apply
to both monopile and jacket installation. These zones vary depending on
species and are shown in Table 16. All distances to clearance zones are
the radius from the center of the pile.
Table 16--Proposed Clearance Zones During Vineyard Wind Pile Driving
------------------------------------------------------------------------
Clearance
Species zone
------------------------------------------------------------------------
North Atlantic right whale.................................. * 1,000 m
All other mysticete whales (including humpback, sei, fin and 500 m
minke whale)...............................................
Harbor porpoise............................................. 120 m
All other marine mammals (including dolphins and pinnipeds). 50 m
------------------------------------------------------------------------
* An extended clearance zone of 10 km for North Atlantic right whales is
proposed from May 1-14 and November 1-December 31, as described below.
If a marine mammal is observed approaching or entering the relevant
clearance zones prior to the start of pile driving operations, pile
driving activity will be delayed until either the marine mammal has
voluntarily left the respective clearance zone and been visually
confirmed beyond that clearance zone, or, 30 minutes have elapsed
without re-detection of the animal in the case of mysticetes, sperm
whales, Risso's dolphins and pilot whales, or 15 minutes have elapsed
without re-detection of the animal in the case of all other marine
mammals.
Prior to the start of pile driving activity, the clearance zones
will be monitored for 60 minutes to ensure that they are clear of the
relevant species of marine mammals. Pile driving would only commence
once PSOs have declared the respective clearance zones clear of marine
mammals. Marine mammals observed within a clearance zone will be
allowed to remain in the clearance zone (i.e., must leave of their own
volition), and their behavior will be monitored and documented. The
clearance zones may only be declared clear, and pile driving started,
when the entire clearance zones are visible (i.e., when not obscured by
dark, rain, fog, etc.) for a full 30 minutes prior to pile driving.
Extended Clearance Zones for North Atlantic Right Whales
In addition to the clearance zones described in Table 16, Vineyard
Wind has proposed extended clearance zones for North Atlantic right
whales during certain times of year. These extended zones are designed
to further minimize the potential for right whales to be exposed to
pile driving noise, and are proposed during times of year that are
considered to be ``shoulder seasons'' in terms of right whale presence
in the project area: November 1 through December 31, and May 1 through
May 14. While North Atlantic right whale presence during these times of
year is considered less likely than during the proposed seasonal
closure (January through April), based on the best available
information right whales may occur in the project area during these
times of year (Roberts et al., 2017; Kraus et al., 2016). Extended
clearance zones would be maintained through passive acoustic monitoring
(PAM) as well as by visual observation conducted on aerial or vessel-
based surveys as described below. Extended clearance zones for North
Atlantic right whales are as follows:
May 1 through May 14: An extended clearance zone of 10 km
would be established based on real-time PAM. Real-time PAM would begin
at least 60 minutes prior to pile driving. In addition, an aerial or
vessel-based survey would be conducted across the extended 10 km
extended clearance zone, using visual PSOs to monitor for right whales.
November 1 through December 31: An extended clearance zone
of 10 km would be established based on real-time PAM. In addition, an
aerial survey may be conducted across the extended 10 km extended
clearance zone, using visual PSOs to monitor for right whales.
During these periods (May 1 through May 14 and November 1 through
December 31), if a right whale were detected either via real-time PAM
or vessel-based or aerial surveys within 10 km of the pile driving
location, pile driving would be postponed and would not commence until
the following day, or, until a follow-up aerial or vessel-based survey
could confirm the extended clearance zone is clear of right whales, as
determined by the lead PSO. Aerial surveys would not begin until the
lead PSO on duty determines adequate visibility and at least one hour
after sunrise (on days with sun glare). Vessel-based surveys would not
begin until the lead PSO on duty determines there is adequate
visibility.
Real-time acoustic monitoring would begin at least 60 minutes prior
to pile driving. The real-time PAM system would be designed and
established such that detection capability extends to 10 km from the
pile driving location. The real-time PAM system must ensure that
acoustic detections can be classified (i.e., potentially originating
from a North Atlantic right whale) within 30 minutes of the original
detection. The PAM operator must be trained in identification of
mysticete vocalizations. The PAM operator responsible for determining
if the acoustic detection originated from a North Atlantic right whale
within the 10 km PAM monitoring zone would be required to make such a
determination if they had at least 75 percent confidence that the
vocalization within 10 km of the pile driving location originated from
a North Atlantic right whale. A record of the PAM operator's review of
any acoustic detections would be reported to NMFS.
We note that these proposed extended clearance zones would exceed
the distance to the isopleth that corresponds to the estimated Level B
harassment threshold (4,121 m for a 10.3 m monopile foundation and
3,220 m for a jacket foundation with four piles, based on 6 dB
attenuation), minimizing the potential for exposures above the Level A
harassment threshold as well as the potential for exposures above the
Level B harassment threshold during the times of year when right whales
are most likely to be present in the project area.
Soft Start
The use of a soft start procedure is believed to provide additional
protection to marine mammals by warning marine mammals or providing
them with a chance to leave the area prior to the hammer operating at
full capacity, and typically involves a requirement to initiate sound
from the hammer at reduced energy followed by a waiting period.
Vineyard Wind will utilize soft start techniques for impact pile
driving by performing an initial set of three strikes from the impact
hammer at a reduced energy level followed by a one minute waiting
period. We note that it is difficult to specify the reduction in energy
for any given hammer because of variation across drivers and, for
impact hammers, the actual number of strikes at reduced energy will
vary because operating the hammer at less than full power results in
``bouncing'' of the hammer as it strikes the pile, resulting in
multiple ``strikes''; however, Vineyard Wind has proposed that they
will target less than 40 percent of total hammer energy for the initial
hammer strikes during soft start. The soft start process would be
conducted a total of three times prior to driving each pile (e.g.,
three single strikes followed by a one minute delay, then three
additional single strikes followed by a one minute delay, then a final
set of three single strikes followed by an additional one
[[Page 18374]]
minute delay). Soft start would be required at the beginning of each
day's impact pile driving work and at any time following a cessation of
impact pile driving of thirty minutes or longer.
Shutdown
The purpose of a shutdown is to prevent some undesirable outcome,
such as auditory injury or behavioral disturbance of sensitive species,
by halting the activity. If a marine mammal is observed entering or
within the respective clearance zones (Table 16) after pile driving has
begun, the PSO will request a temporary cessation of pile driving.
Vineyard Wind has proposed that, when called for by a PSO, shutdown of
pile driving would be implemented when feasible but that shutdown would
not always be technically practicable once driving of a pile has
commenced as it has the potential to result in pile instability. We
therefore propose that shutdown would be implemented when feasible,
with a focus on other proposed mitigation measures as the primary means
of minimizing potential impacts on marine mammals from noise related to
pile driving. If shutdown is called for by a PSO, and Vineyard Wind
determines a shutdown to be technically feasible, pile driving would be
halted immediately.
In situations when shutdown is called for but Vineyard Wind
determines shutdown is not practicable due to human safety or
operational concerns, reduced hammer energy would be implemented when
practicable. After shutdown, pile driving may be initiated once all
clearance zones are clear of marine mammals for the minimum species-
specific time periods, or, if required to maintain installation
feasibility. Installation feasibility refers to ensuring that the pile
installation results in a usable foundation for the WTG (e.g.,
installed to the target penetration depth without refusal and with a
horizontal foundation/tower interface flange). In cases where pile
driving is already started and a PSO calls for shutdown, the lead
engineer on duty will evaluate the following to determine whether
shutdown is feasible: (1) Use the site-specific soil data and the real-
time hammer log information to judge whether a stoppage would risk
causing piling refusal at re-start of piling; and (2) Check that the
pile penetration is deep enough to secure pile stability in the interim
situation, taking into account weather statistics for the relevant
season and the current weather forecast. Determinations by the lead
engineer on duty will be made for each pile as the installation
progresses and not for the site as a whole.
Visibility Requirements
Pile driving would not be initiated at night, or, when the full
extent of all relevant clearance zones cannot be confirmed to be clear
of marine mammals, as determined by the lead PSO on duty. The clearance
zones may only be declared clear, and pile driving started, when the
full extent of all clearance zones are visible (i.e., when not obscured
by dark, rain, fog, etc.) for a full 30 minutes prior to pile driving.
Pile driving may continue after dark only when the driving of the same
pile began during the day when clearance zones were fully visible and
must proceed for human safety or installation feasibility reasons.
Sound Attenuation Devices
Vineyard Wind would implement sound attenuation technology that
would target at least a 12 dB reduction in pile driving noise, and that
must achieve at least a 6 dB reduction in pile driving noise, as
described above. The attenuation system may include one of the
following or some combination of the following: A Noise Mitigation
System, Hydro-sound Damper, Noise Abatement System, and/or bubble
curtain. Vineyard Wind would also have a second back-up attenuation
device (e.g., bubble curtain or similar) available, if needed, to
achieve the targeted reduction in noise levels, pending results of
sound field verification testing.
If Vineyard Wind uses a bubble curtain, 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 for the full circumference of the ring, and
the weights attached to the bottom ring shall ensure 100 percent
mudline contact. No parts of the ring or other objects shall prevent
full mudline contact. Vineyard Wind would require that construction
contractors train personnel in the proper balancing of airflow to the
bubblers, and would require that construction contractors submit an
inspection/performance report for approval by Vineyard Wind within 72
hours following the performance test. Corrections to the attenuation
device to meet the performance standards would occur prior to impact
driving.
Monitoring Protocols
Monitoring would be conducted before, during, and after pile
driving activities. In addition, observers will record all incidents of
marine mammal occurrence, regardless of distance from the construction
activity, and monitors will document any behavioral reactions in
concert with distance from piles being driven. Observations made
outside the clearance zones will not result in delay of pile driving;
that pile segment may be completed without cessation, unless the marine
mammal approaches or enters the clearance zone, at which point pile
driving activities would be halted when practicable, as described
above. 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.
The following additional measures apply to visual monitoring:
(1) Monitoring will be conducted by qualified, trained PSOs, who
will be placed on the installation vessel, which represents the best
vantage point to monitor for marine mammals and implement shutdown
procedures when applicable;
(2) A minimum of two PSOs will be on duty at all times during pile
driving activity. A minimum of four PSOs will be stationed at the pile
driving site at all times during pile driving activity;
(3) PSOs may not exceed four consecutive watch hours; must have a
minimum two hour break between watches; and may not exceed a combined
watch schedule of more than 12 hours in a 24- hour period;
(4) Monitoring will be conducted from 60 minutes prior to
commencement of pile driving, throughout the time required to drive a
pile, and for 30 minutes following the conclusion of pile driving;
(5) PSOs will have no other construction-related tasks while
conducting monitoring;
(6) PSOs should have the following minimum qualifications:
Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
Ability to conduct field observations and collect data
according to assigned protocols;
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
[[Page 18375]]
Writing skills sufficient to document 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 of marine mammals from
construction noise 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.
Observer teams employed by Vineyard Wind in satisfaction of the
mitigation and monitoring requirements described herein must meet the
following additional requirements:
Independent observers (i.e., not construction personnel)
are required;
At least one observer must have prior experience working
as an observer;
Other observers may substitute education (degree in
biological science or related field) or training for experience;
One observer will be designated as lead observer or
monitoring coordinator. The lead observer must have prior experience
working as an observer; and
NMFS will require submission and approval of observer CVs.
Vessel Strike Avoidance
Vessel strike avoidance measures will include, but are not limited
to, the following, except under circumstances when complying with these
measures would put the safety of the vessel or crew at risk:
All vessel operators and crew must maintain vigilant watch
for cetaceans and pinnipeds, and slow down or stop their vessel to
avoid striking these protected species;
All vessels transiting to and from the WDA and traveling
over 10 knots would have a visual observer who has undergone marine
mammal training stationed on the vessel. Visual observers monitoring
the vessel strike avoidance zone may be third-party observers (i.e.,
PSOs) or crew members, but crew members responsible for these duties
must be provided sufficient training to distinguish marine mammals from
other phenomena and broadly to identify a marine mammal as a right
whale, other whale (defined in this context as sperm whales or baleen
whales other than right whales), or other marine mammal;
From November 1 through May 14, all vessels must travel at
less than 10 knots (18.5 km/hr) within the WDA;
From November 1 through May 14, when transiting to or from
the WDA, vessels must either travel at less than 10 knots, or, must
implement visual surveys with at least one visual observer to monitor
for North Atlantic right whales (with the exception of vessel transit
within Nantucket Sound);
All vessels must travel at 10 knots (18.5 km/hr) or less
within any designated Dynamic Management Area (DMA), with the exception
of crew transfer vessels;
Crew transfer vessels traveling within any designated DMA
must travel at 10 knots (18.5 km/hr) or less, unless North Atlantic
right whales are clear of the transit route and WDA for two consecutive
days, as confirmed by vessel based surveys conducted during daylight
hours and real-time PAM, or, by an aerial survey, conducted once the
lead aerial observer determines adequate visibility. If confirmed clear
by one of the measures above, vessels transiting within a DMA must
employ at least two visual observers to monitor for North Atlantic
right whales. If a North Atlantic right whale is observed within or
approaching the transit route, vessels must operate at less than 10
knots until clearance of the transit route for two consecutive days is
confirmed by the procedures described above;
All vessels greater than or equal to 65 ft (19.8 m) in
overall length will comply with 10 knot (18.5 km/hr) or less speed
restriction in any Seasonal Management Area (SMA) per the NOAA ship
strike reduction rule (73 FR 60173; October 10, 2008);
All vessel operators will reduce vessel speed to 10 knots
(18.5 km/hr) or less when any large whale, any mother/calf pairs, pods,
or large assemblages of non-delphinoid cetaceans are observed near
(within 100 m (330 ft)) an underway vessel;
All survey vessels will maintain a separation distance of
500 m (1,640 ft) or greater from any sighted North Atlantic right
whale;
If underway, vessels must steer a course away from any
sighted North Atlantic right whale at 10 knots (18.5 km/hr) or less
until the 500 m (1,640 ft) minimum separation distance has been
established. If a North Atlantic right whale is sighted in a vessel's
path, or within 500 m (330 ft) to an underway vessel, the underway
vessel must reduce speed and shift the engine to neutral. Engines will
not be engaged until the right whale has moved outside of the vessel's
path and beyond 500 m. If stationary, the vessel must not engage
engines until the North Atlantic right whale has moved beyond 500 m;
All vessels will maintain a separation distance of 100 m
(330 ft) or greater from any sighted non-delphinoid cetacean. If
sighted, the vessel underway must reduce speed and shift the engine to
neutral, and must not engage the engines until the non-delphinoid
cetacean has moved outside of the vessel's path and beyond 100 m. If a
vessel is stationary, the vessel will not engage engines until the non-
delphinoid cetacean has moved out of the vessel's path and beyond 100
m;
All vessels will maintain a separation distance of 50 m
(164 ft) or greater from any sighted delphinoid cetacean, with the
exception of delphinoid cetaceans that voluntarily approach the vessel
(i.e., bow ride). Any vessel underway must remain parallel to a sighted
delphinoid cetacean's course whenever possible, and avoid excessive
speed or abrupt changes in direction. Any vessel underway must reduce
vessel speed to 10 knots (18.5 km/hr) or less when pods (including
mother/calf pairs) or large assemblages of delphinoid cetaceans are
observed. Vessels may not adjust course and speed until the delphinoid
cetaceans have moved beyond 50 m and/or the abeam of the underway
vessel;
All vessels will maintain a separation distance of 50 m
(164 ft) or greater from any sighted pinniped; and
All vessels underway will not divert or alter course in
order to approach any whale, delphinoid cetacean, or pinniped. Any
vessel underway will avoid excessive speed or abrupt changes in
direction to avoid injury to the sighted cetacean or pinniped.
Vineyard Wind will ensure that vessel operators and crew maintain a
vigilant watch for marine mammals by slowing down or stopping the
vessel to avoid striking marine mammals. Project-specific training will
be conducted for all vessel crew prior to the start of the construction
activities. Confirmation of the training and understanding of the
requirements will be documented on a training course log sheet.
We have carefully evaluated Vineyard Wind's proposed mitigation
measures and considered a range of other measures in the context of
ensuring that we prescribed the means of effecting the least
practicable adverse impact on the affected marine mammal species and
stocks and their habitat. Based on our evaluation of these measures, we
have preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable adverse impact on
marine mammal species or stocks and their habitat, paying particular
attention to
[[Page 18376]]
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for subsistence uses.
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.
Visual Marine Mammal Observations
Vineyard Wind will collect sighting data and behavioral responses
to pile driving activity for marine mammal species observed in the
region of activity during the period of activity. All observers will be
trained in marine mammal identification and behaviors and are required
to have no other construction-related tasks while conducting
monitoring. PSOs would monitor all clearance zones at all times. PSOs
would also monitor Level B harassment zones (i.e., 4,121 m for
monopiles and 3,220 m for jacket piles) and would document any marine
mammals observed within these zones, to the extent practicable (noting
that some distances to these zones are too large to fully observe).
Vineyard Wind would conduct monitoring before, during, and after pile
driving, with observers located at the best practicable vantage points
on the pile driving vessel.
Vineyard Wind would implement the following procedures for pile
driving:
A minimum of two PSOs will maintain watch at all times
when pile driving is underway.
PSOs would be located at the best vantage point(s) on the
installation vessel to ensure that they are able to observe the entire
clearance zones and as much of the Level B harassment zone as possible.
During all observation periods, PSOs will use binoculars
and the naked eye to search continuously for marine mammals.
PSOs will be equipped with reticle binoculars and night
vision binoculars.
If the clearance zones are obscured by fog or poor
lighting conditions, pile driving will not be initiated until clearance
zones are fully visible. Should such conditions arise while impact
driving is underway, the activity would be halted when practicable, as
described above.
The clearance zones will be monitored for the presence of
marine mammals before, during, and after all pile driving activity.
When monitoring is required during vessel transit (as described
above), the PSO(s) will be stationed on vessels at the best vantage
points to ensure maintenance of standoff distances between marine
mammals and vessels (as described above). Vineyard Wind would implement
the following measures during vessel transit when there is an
observation of a marine mammal:
PSOs will record the vessel's position and speed, water
depth, sea state, and visibility will be recorded at the start and end
of each observation period, and whenever there is a change in any of
those variables that materially affects sighting conditions.
PSOs will record the time, location, speed, and activity
of the vessel, sea state, and visibility.
Individuals implementing the monitoring protocol will assess its
effectiveness using an adaptive approach. PSOs will use their best
professional judgment throughout implementation and seek improvements
to these methods when deemed appropriate. Any modifications to the
protocol will be coordinated between NMFS and Vineyard Wind.
Data Collection
We require that observers use standardized data forms. Among other
pieces of information, Vineyard Wind will record detailed information
about any implementation of delays or shutdowns, including the distance
of animals to the pile and a description of specific actions that
ensued and resulting behavior of the animal, if any. 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., wind speed, percent cloud 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;
Distance from pile driving activities to marine mammals
and distance from the marine mammals to the observation point;
Type of construction activity (e.g., monopile or jacket
pile installation) when marine mammals are observed.
Description of implementation of mitigation measures
(e.g., delay or shutdown).
Locations of all marine mammal observations; and
Other human activity in the area.
Vineyard Wind will note behavioral observations, to the extent
practicable, if an animal has remained in the area during construction
activities.
Acoustic Monitoring
Vineyard Wind would utilize a PAM system to supplement visual
monitoring. The PAM system would be monitored by a minimum of one
acoustic PSO beginning at least 30 minutes prior to ramp-up of pile
driving and at all times during pile driving. Acoustic PSOs would
immediately communicate all detections of marine
[[Page 18377]]
mammals to visual PSOs, including any determination regarding species
identification, distance, and bearing and the degree of confidence in
the determination. PAM would be used to inform visual monitoring during
construction; no mitigation actions would be required on PAM detection
alone. The PAM system would not be located on the pile installation
vessel.
Acoustic PSOs may be on watch for a maximum of four consecutive
hours followed by a break of at least two hours between watches.
Acoustic PSOs would be required to complete specialized training for
operating PAM systems. PSOs can act as acoustic or visual observers
(but not simultaneously) as long as they demonstrate that their
training and experience are sufficient to perform each task.
Vineyard Wind will also conduct hydroacoustic monitoring for a
subset of impact-driven piles. Hydroacoustic monitoring would be
performed for at least one of each pile type (e.g., monopile and jacket
pile). For each pile that is monitored via hydroacoustic monitoring, a
minimum of two autonomous acoustic recorders will be deployed. Each
acoustic recorder will consist of a vertical line array with two
hydrophones deployed at depths spanning the water column (one near the
seabed and one in the water column).
Vineyard Wind would be required to conduct sound source
verification during pile driving. Sound source verification would be
required during impact installation of a 10.3 m monopile (or, of the
largest diameter monopile used over the duration of the IHA) with noise
attenuation activated; during impact installation of the same size
monopile, without noise attenuation activated (if a monopile is
installed without noise attenuation; impact pile driving without noise
attenuation would be limited to one monopile); and, during impact
installation of the largest jacket pile used over the duration of the
IHA. Sound source measurements would be conducted at distances of
approximately 50, 500, 750 and 1,500 m from the pile being driven.
Vineyard Wind would be required to empirically determine the
distances to the isopleths corresponding to the Level A and Level B
harassment thresholds either by extrapolating from in situ measurements
conducted at several points between 50, 500, 750, and 1,500 m from the
pile being driven, or by direct measurements to locate the distance
where the received levels reach the relevant thresholds or below.
Isopleths corresponding to the Level A and Level B harassment
thresholds would be empirically verified for impact driving of the
largest diameter monopile used over the duration of the IHA, and impact
driving of the largest diameter jacket pile used over the duration of
the IHA. For verification of the extent of the Level B harassment zone,
Vineyard Wind would be required to report the measured or extrapolated
distances where the received levels SPLrms decay to 160-dB, as well as
integration time for such SPLrms.
The acoustic monitoring report would include: Peak sound pressure
level (SPLpk), root-mean-square sound pressure level that contains 90
percent of the acoustic energy (SPLrms), single strike sound exposure
level, integration time for SPLrms, SELss spectrum, and 24-hour
cumulative SEL extrapolated from measurements. All these levels would
be reported in the form of median, mean, max, and minimum. The sound
levels reported would be in median and linear average (i.e., taking
averages of sound intensity before converting to dB). The acoustic
monitoring report would also include a description of depth and
sediment type at the recording location.
Recording would also occur when no construction activities are
occurring in order to establish ambient sound levels. Vineyard Wind
would also conduct real-time PAM during certain times of year to
facilitate mitigation (as described above).
Reporting
A draft report would be submitted to NMFS within 90 days of the
completion of monitoring for each installation's in-water work window.
The report would include marine mammal observations pre-activity,
during-activity, and post-activity during pile driving days, and would
also provide descriptions of any behavioral responses to construction
activities by marine mammals. The report would detail the monitoring
protocol, summarize the data recorded during monitoring including an
estimate of the number of marine mammals that may have been harassed
during the period of the report, and describe any mitigation actions
taken (i.e., delays or shutdowns due to detections of marine mammals,
and documentation of when shutdowns were called for but not implemented
and why). The report would also include results from acoustic
monitoring including dates and times of all detections, types and
nature of sounds heard, whether detections were linked with visual
sightings, water depth of the hydrophone array, bearing of the animal
to the vessel (if determinable), species or taxonomic group (if
determinable), spectrogram screenshot, a record of the PAM operator's
review of any acoustic detections, and any other notable information. A
final report must be submitted within 30 days following resolution of
comments on the draft report.
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 project, as
described previously, have the potential to disturb or temporarily
displace marine mammals. Specifically, the specified activities may
result in take, in the form of Level A harassment (potential injury) or
Level B harassment (potential behavioral disturbance) from underwater
sounds generated from pile driving. Potential takes could occur if
individual marine mammals are present in the ensonified zone when pile
driving is occurring.
To avoid repetition, the majority of our analyses apply to all the
species listed in Table 1, given that many of the anticipated effects
of the proposed project on different marine mammal
[[Page 18378]]
stocks are expected to be relatively similar in nature. Where there are
meaningful differences between species or stocks--as is the case of the
North Atlantic right whale--they are included as separate sub-sections
below.
North Atlantic Right Whales
North Atlantic right whales are currently threatened by low
population abundance, higher than normal mortality rates and lower than
normal reproductive rates. As described above, the project area
represents part of an important migratory area for North Atlantic right
whales, which make annual migrations up and down the Atlantic coast.
Due to the current status of North Atlantic right whales, and the
spatial overlap of the proposed project with an area of biological
significance for right whales, the potential impacts of the proposed
project on right whales warrant particular attention.
As described above, North Atlantic right whale presence in the
project area is seasonal. As a result of several years of aerial
surveys and PAM deployments in the area we have confidence that right
whales are expected in the project area during certain times of year
while at other times of year right whales are not expected to occur in
the project area. During aerial surveys conducted from 2011-2015 in the
project area, right whale sightings occurred only December through
April, with no sightings from May through November (Kraus et al.,
2016). There was not significant variability in sighting rate among
years, indicating consistent annual seasonal use of the area by right
whales (Kraus et al., 2016).
Due to this seasonal pattern in right whale occurrence in the
project area, we expect the most significant measure in minimizing
impacts to right whales to be the proposed seasonal closure that would
occur from January through April, when right whale abundance in the
project area is greatest. In addition, proposed mitigation measures
outside of those months--including a 10 km clearance zone facilitated
through PAM and vessel or aerial surveys during the ``shoulder
seasons'' when right whale abundance in the area is lower than the peak
months of January to April, as well as a 1 km clearance zone for all
other months--will greatly minimize any takes that may otherwise occur
outside of the months of peak abundance in the area. As a result of
these mitigation measures, we expect the already small potential for
right whales to be exposed to project-related sound above the Level A
harassment threshold to be eliminated. We also expect these proposed
measures to greatly reduce the amount of exposures to project-related
noise above the Level B harassment threshold, the duration and
intensity of any exposures above the Level B harassment threshold that
do occur, as well as the potential for mother-calf pairs to be exposed
to project-related noise above the Level B harassment threshold during
their annual migration through the project area. No serious injury or
mortality of North Atlantic right whales would be expected even in the
absence of the proposed mitigation measures.
Instances of Level B harassment of North Atlantic right whales will
be reduced to the level of least practicable adverse impact through use
of proposed mitigation measures, including soft start. Any individuals
that are exposed above the Level B harassment threshold are expected to
move away from the sound source and temporarily avoid the areas of pile
driving. We expect that any avoidance of the project area by North
Atlantic right whales would be temporary in nature and that any North
Atlantic right whales that avoid the project area during construction
would not be permanently displaced. Even repeated Level B harassment of
some small subset of the overall stock is unlikely to result in any
significant realized decrease in viability for the affected
individuals, and thus would not result in any adverse impact to the
stock as a whole.
Prey for North Atlantic right whales are mobile and broadly
distributed throughout the project area; therefore, right whales that
may be temporarily displaced during construction activities are
expected to be able to resume foraging once they have moved away from
areas with disturbing levels of underwater noise. Because of the
temporary nature of the disturbance and the availability of similar
habitat and resources in the surrounding area, the impacts to right
whales and the food sources that they utilize are not expected to cause
significant or long-term consequences for individual right whales or
their population. In addition, there are no right whale mating or
calving areas within the proposed project area.
As described above, North Atlantic right whales are experiencing an
ongoing UME. However, as described above, no injury of right whales as
a result of the proposed project is expected or proposed for
authorization, and Level B harassment takes of right whales are
expected to be in the form of avoidance of the immediate area of
construction. As no injury or mortality is expected or proposed for
authorization, and Level B harassment of North Atlantic right whales
will be reduced to the level of least practicable adverse impact
through use of proposed mitigation measures, the proposed authorized
takes of right whales would not exacerbate or compound the ongoing UME
in any way.
NMFS concludes that exposures to North Atlantic right whales would
be greatly reduced due to the seasonal restrictions, and additional
proposed mitigation measures that would ensure that any exposures above
the Level B harassment threshold would result in only short-term
effects to individuals exposed. With implementation of the proposed
mitigation requirements, take by Level A harassment is unlikely and is
therefore not proposed for authorization. Potential impacts associated
with Level B harassment would include only low-level, temporary
behavioral modifications, most likely in the form of avoidance behavior
or potential alteration of vocalizations. In order to evaluate whether
or not individual behavioral responses, in combination with other
stressors, impact animal populations, scientists have developed
theoretical frameworks which can then be applied to particular case
studies when the supporting data are available. One such framework is
the population consequences of disturbance model (PCoD), which attempts
to assess the combined effects of individual animal exposures to
stressors at the population level (NAS 2017). Nearly all PCoD studies
and experts agree that infrequent exposures of a single day or less are
unlikely to impact individual fitness, let alone lead to population
level effects (Booth et al., 2016; Booth et al., 2017; Christiansen and
Lusseau 2015; Farmer et al., 2018; Harris et al., 2017; Harwood and
Booth 2016; King et al., 2015; McHuron et al., 2018; NAS 2017; New et
al., 2014; Pirotta et al., 2018; Southall et al., 2007; Villegas-
Amtmann et al., 2015). Since NMFS expects that any exposures would be
very brief, and repeat exposures to the same individuals are unlikely,
any behavioral responses that would occur due to animals being exposed
to construction activity are expected to be temporary, with behavior
returning to a baseline state shortly after the acoustic stimuli
ceases. Given this, and NMFS' evaluation of the available PCoD studies,
any such behavioral responses are not expected to impact individual
animals' health or have effects on individual animals' survival or
reproduction, thus no detrimental impacts at the population level are
anticipated. North Atlantic right whales
[[Page 18379]]
may temporarily avoid the immediate area but are not expected to
permanently abandon the area. Impacts to breeding, feeding, sheltering,
resting, or migration are not expected, nor are shifts in habitat use,
distribution, or foraging success. NMFS does not anticipate North
Atlantic right whales takes that would result from the proposed project
would impact annual rates of recruitment or survival. Thus, any takes
that occur would not result in population level impacts.
All Other Marine Mammal Species
Impact pile driving has source characteristics (short, sharp pulses
with higher peak levels and sharper rise time to reach those peaks)
that are potentially injurious or more likely to produce severe
behavioral reactions. However, modeling indicates there is limited
potential for injury even in the absence of the proposed mitigation
measures, with several species predicted to experience no Level A
harassment based on modeling results (Tables 10-13). In addition, the
potential for injury is expected to be greatly minimized through
implementation of the proposed mitigation measures including soft
start, use of a sound attenuation system, and the implementation of
clearance zones that would facilitate a delay of pile driving if marine
mammals were observed approaching or within areas that could be
ensonified above sound levels that could result in auditory injury.
Given sufficient notice through use of soft start, marine mammals are
expected to move away from a sound source that is annoying prior to its
becoming potentially injurious or resulting in more severe behavioral
reactions. The proposed requirement that pile driving can only commence
when the full extent of all clearance zones are fully visible to PSOs
will ensure a high marine mammal detection capability, enabling a high
rate of success in implementation of clearance zones to avoid injury.
We expect that any exposures above the Level A harassment threshold
would be in the form of 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. If hearing impairment
occurs, it is most likely that the affected animal would lose a few
decibels in its hearing sensitivity, which in most cases is not likely
to meaningfully affect its ability to forage and communicate with
conspecifics. However, given sufficient notice through use of soft
start, marine mammals are expected to move away from a sound source
that is annoying prior to its becoming potentially injurious or
resulting in more severe behavioral reactions.
Additionally, the numbers of exposures above the Level A harassment
proposed for authorization are relatively low for all marine mammal
stocks and species: For 13 of 15 stocks, we propose to authorize less
than 10 takes by Level A harassment over the duration of the project;
for the other two stocks we propose to authorize no more than 35 takes
by Level A harassment. 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, thereby minimizing the degree of PTS that would be incurred.
Repeated exposures of individuals to relatively low levels of sound
outside of preferred habitat areas are unlikely to significantly
disrupt critical behaviors. Thus, even repeated Level B harassment of
some small subset of an overall stock is unlikely to result in any
significant realized decrease in viability for the affected
individuals, and thus would not result in any adverse impact to the
stock as a whole. Level B harassment will be reduced to the level of
least practicable adverse impact through use of proposed mitigation
measures and, if sound produced by project activities is sufficiently
disturbing, marine mammals are likely to simply avoid the area while
the activity is occurring. 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; HDR, Inc., 2012; Lerma, 2014). Most likely,
individuals will simply move away from the sound source and temporarily
avoid the area where pile driving is occurring. Therefore, we expect
that animals annoyed by project sound would simply avoid the area
during pile driving in favor of other, similar habitats. We expect that
any avoidance of the project area by marine mammals would be temporary
in nature and that any marine mammals that avoid the project area
during construction would not be permanently displaced.
Feeding behavior is not likely to be significantly impacted, as
prey species are mobile and are broadly distributed throughout the
project area; therefore, marine mammals that may be temporarily
displaced during construction activities are expected to be able to
resume foraging once they have moved away from areas with disturbing
levels of underwater noise. Because of the temporary nature of the
disturbance and the availability of similar habitat and resources in
the surrounding area, the impacts to marine mammals and the food
sources that they utilize are not expected to cause significant or
long-term consequences for individual marine mammals or their
populations. There are no areas of notable biological significance for
marine mammal feeding known to exist in the project area. In addition,
there are no rookeries or mating or calving areas known to be
biologically important to marine mammals within the proposed project
area.
NMFS concludes that exposures to marine mammals due to the proposed
project would result in only short-term effects to individuals exposed.
Marine mammals may temporarily avoid the immediate area but are not
expected to permanently abandon the area. Impacts to breeding, feeding,
sheltering, resting, or migration are not expected, nor are shifts in
habitat use, distribution, or foraging success. NMFS does not
anticipate the marine mammal takes that would result from the proposed
project would impact annual rates of recruitment or survival.
As described above, humpback whales, minke whales, and gray, harbor
and harp seals are experiencing ongoing UMEs. For minke whales,
although the ongoing UME is under investigation (as occurs for all
UMEs), this event does not provide cause for concern regarding
population level impacts, as the likely population abundance is greater
than 20,000 whales. Even though the PBR value is based on an abundance
for U.S. waters that is negatively biased and a small fraction of the
true population abundance, annual M/SI does not exceed the calculated
PBR value for minke whales. With regard to humpback whales, the UME
does not yet provide cause for concern regarding population-level
impacts. Despite the UME, the relevant population of humpback whales
(the West Indies breeding population, or distinct population segment
(DPS)) remains healthy. 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. The status review identified harmful algal
blooms, vessel collisions, and fishing gear entanglements as relevant
threats for this DPS, but noted that all other
[[Page 18380]]
threats are considered likely to have no or minor impact on population
size or the growth rate of this DPS (Bettridge et al., 2015). 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. With regard to gray seals, harbor
seals and harp seals, although the ongoing UME is under investigation,
the UME does not yet provide cause for concern regarding population-
level impacts to any of these stocks. For harbor seals, the population
abundance is over 75,000 and annual M/SI (345) is well below PBR
(2,006) (Hayes et al., 2018). For gray seals, the population abundance
is over 27,000, and abundance is likely increasing in the U.S. Atlantic
EEZ and in Canada (Hayes et al., 2018). For harp seals, the current
population trend in U.S. waters is unknown, as is PBR (Hayes et al.,
2018), however the population abundance is over 7 million seals,
suggesting that the UME is unlikely to result in population-level
impacts (Hayes et al., 2018). Proposed authorized takes by Level A
harassment for all species are very low (i.e., no more than 10 takes by
Level A harassment proposed for any of these species) and as described
above, any Level A harassment would be expected to be in the form of
slight PTS, i.e., minor degradation of hearing capabilities which is
not likely to meaningfully affect the ability to forage or communicate
with conspecifics. No serious injury or mortality is expected or
proposed for authorization, and Level B harassment of humpback whales
and minke whales and gray, harbor and harp seals will be reduced to the
level of least practicable adverse impact through use of proposed
mitigation measures. As such, the proposed authorized takes of humpback
whales and minke whales would not exacerbate or compound the ongoing
UMEs in any way.
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 or serious injury is anticipated or proposed
for authorization;
The anticipated impacts of the proposed activity on marine
mammals would be temporary behavioral changes due to avoidance of the
project area and limited instances of Level A harassment in the form of
a slight PTS;
Potential instances of exposure above the Level A
harassment threshold are expected to be relatively low for most
species; any potential for exposures above the Level A harassment
threshold would be minimized by proposed mitigation measures including
clearance zones;
Total proposed authorized takes as a percentage of
population are very low for all species and stocks (i.e., less than 6
percent for five stocks, and less than 1 percent for the remaining 10
stocks);
The availability of alternate areas of similar habitat
value for marine mammals to temporarily vacate the project area during
the proposed project to avoid exposure to sounds from the activity;
Effects on species that serve as prey species for marine
mammals from the proposed project are expected to be short-term and are
not expected to result in significant or long-term consequences for
individual marine mammals, or to contribute to adverse impacts on their
populations;
There are no known important feeding, breeding or calving
areas in the project area. A biologically important migratory area
exists for North Atlantic right whales, however the proposed seasonal
moratorium on construction is expected to largely avoid impacts to the
right whale migration, as described above;
The proposed mitigation measures, including visual and
acoustic monitoring, clearance zones, and soft start, are expected to
minimize potential impacts to marine mammals.
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.
We propose to authorize incidental take of 15 marine mammal stocks.
The total amount of taking proposed for authorization is less than 6
percent for five of these stocks, and less than 1 percent for the
remaining 10 stocks (Table 15), which we consider to be relatively
small percentages and we preliminarily find are small numbers of marine
mammals relative to the estimated overall population abundances for
those stocks.
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 all 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. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species.
NMFS is proposing to authorize take of North Atlantic right, fin,
sei, and sperm whales, which are listed under the ESA. The NMFS Office
of Protected Resources has requested initiation of Section 7
consultation with the NMFS Greater Atlantic Regional Fisheries Office
for the issuance of this IHA. NMFS will conclude the ESA consultation
prior to reaching a determination regarding the proposed issuance of
the authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to Vineyard Wind for
[[Page 18381]]
conducting construction activities south of Massachusetts for a period
of one year, provided the previously mentioned mitigation, monitoring,
and reporting requirements are incorporated. A draft of the proposed
IHA can be found at: 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
construction of the Vineyard Wind offshore wind project. We also
request comment on the potential for 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 our final
decision on the request for MMPA authorization.
On a case-by-case basis, NMFS may issue a one-year IHA renewal with
an expedited public comment period (15 days) when: (1) Another year of
identical or nearly identical activities as described in the Specified
Activities section is planned or (2) the activities would not be
completed by the time the IHA expires and a second IHA would allow for
completion of the activities beyond that described in the Dates and
Duration section, 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
proposed 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); and
(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: April 24, 2019.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2019-08666 Filed 4-29-19; 8:45 am]
BILLING CODE 3510-22-P