[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





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National Oceanic and Atmospheric Administration





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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]]


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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.

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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.

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    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

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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