Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Offshore Wind Construction Activities off of Virginia, 14901-14924 [2020-05281]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 85, Number 51 (Monday, March 16, 2020)]
[Notices]
[Pages 14901-14924]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-05281]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XR075]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Offshore Wind Construction 
Activities off of Virginia

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for comments.

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SUMMARY: NMFS has received a request from Virginia Electric and Power 
Company, d/b/a Dominion Energy Virginia (Dominion), for authorization 
to take marine mammals incidental to conducting construction activities 
off the coast of Virginia in the area of Research Lease of Submerged 
Lands for Renewable Energy Activities on the Outer Continental Shelf 
(OCS) Offshore Virginia (Lease No. OCS-A-0497), in support of the 
Coastal Virginia Offshore Wind (CVOW) Project. 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 April 
15, 2020.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical

[[Page 14902]]

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/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable 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 applications 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained by visiting the internet at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. 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 evaluate our proposed action (i.e., the promulgation of 
regulations and subsequent issuance of incidental take authorization) 
and alternatives with respect to potential impacts on the human 
environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 of the Companion Manual for NAO 216-6A, 
which do not individually or cumulatively have the potential for 
significant impacts on the quality of the human environment and for 
which we have not identified any extraordinary circumstances that would 
preclude this categorical exclusion. Accordingly, NMFS has 
preliminarily determined that the proposed action qualifies to be 
categorically excluded from further NEPA review.
    Information in Dominion's application and this notice collectively 
provide the environmental information related to proposed issuance of 
these regulations and subsequent incidental take authorization for 
public review and comment. We will review all comments submitted in 
response to this notice prior to concluding our NEPA process or making 
a final decision on the request for incidental take authorization.

Summary of Request

    On September 13, 2019, NMFS received a request from Dominion for an 
IHA to take marine mammals incidental to construction activities off 
the coast of Virginia in the area of Research Lease of Submerged Lands 
for Renewable Energy Activities on the Outer Continental Shelf (OCS) 
Offshore Virginia (Lease No. OCS-A-0497) in support of the CVOW 
project. A revised application was received on January 21, 2020. NMFS 
deemed that request to be adequate and complete. Dominion's request is 
for the take of seven marine mammal species by Level B harassment that 
would occur over the course of two days of in-water construction. 
Neither Dominion nor NMFS expects serious injury or mortality to result 
from this activity and the activity is expected to last no more than 
one year, therefore, an IHA is appropriate.

Description of the Proposed Activity

Overview

    The CVOW Project (the Project) calls for development of two 6-
megawatt wind turbines on a site leased by the Virginia Department of 
Mines Minerals and Energy (DMME). Dominion has an agreement with DMME 
to build and operate the two turbines within the 2,135-acre site, which 
lies 27 miles (mi) off the coast of Virginia Beach, Virginia. Dominion 
has contracted with [Oslash]rsted for construction of the two turbines. 
The goals of the Project are to provide electricity to Virginia and to 
inform plans for a future large-scale commercial offshore wind 
development in the adjacent Virginia Wind Energy Area that is also 
leased by Dominion.
    Dominion proposes to conduct in-water construction activities in 
the area of Research Lease of Submerged Lands for Renewable Energy 
Activities on the OCS Offshore Virginia (Lease No. OCS-A-0497) (the 
Lease Area; see Figure 1-1 in the IHA application), as well as cable-
lay and marine site characterization surveys along a 27-mile (mi) 
submarine cable corridor to a landfall location in Virginia, in support 
of the Project. The objective of the construction activities is to 
support installation of the wind turbine generator (WTG) foundations.

Dates and Duration

    Construction activities are expected to occur during two days and 
could occur any time between May and October, 2020. Cable-lay and site 
characterization survey activities could occur for up to three months 
between May and October, 2020.

Specific Geographic Region

    Dominion's activities would occur in the Northwest Atlantic Ocean 
within Federal and state waters. Construction activities would occur 
within the Lease Area approximately 27 miles offshore Virginia (see 
Figure 1-1 in the IHA application) while cable-lay and site 
characterization survey activities would occur between the Lease Area 
and a landfall location in Virginia.

[[Page 14903]]

Detailed Description of the Specified Activities

    As described above, Dominion's proposed activities include in-water 
construction, cable laying, and marine site characterization surveys. 
Of these activities, only in-water construction, which would occur for 
a total of two days, is expected to result in the incidental take of 
marine mammals. These activities are described in greater detail below.

Cable-Lay Activities

    A power cable would be used to transmit the energy generated by the 
WTGs to substations on land. This cable would be buried under the 
seabed. Specialized vessels designed for laying and burying cables 
under the seabed would be used for cable-laying activities. To complete 
cable installation in one continuous run, Dominion has proposed that 
cable installation operations would be conducted continuously 24 hours 
per day. The cable would be buried by the use of a jet plow or plow 
which create subsea trenches. The underwater noise produced by subsea 
trenching operations are not expected to rise to a level that would 
result in the take of marine mammals.
    Throughout the cable lay process, a dynamic positioning (DP) 
enabled cable lay vessel would maintain its position (fixed location or 
predetermined track) by means of its propellers and thrusters using a 
Global Positioning System, which describes the ship's position by 
sending information to an onboard computer that controls the thrusters. 
DP vessels possess the ability to operate with positioning accuracy, 
safety, and reliability without the need for anchors, anchor handling 
tugs and mooring lines. Sound produced through use of DP thrusters is 
similar to that produced by transiting vessels and DP thrusters are 
typically operated either in a similarly predictable manner or used for 
short durations around stationary activities. NMFS has determined the 
acoustic impacts from DP thrusters are not likely to result in take of 
marine mammals in the absence of activity- or location-specific 
circumstances that may otherwise represent specific concerns for marine 
mammals (i.e., activities proposed in area known to be of particular 
importance for a particular species), or associated activities that may 
increase the potential to result in take when in concert with DP 
thrusters. In this case, we are not aware of any such circumstances. 
Therefore, NMFS believes the likelihood of DP thrusters used during 
cable lay activities resulting in harassment of marine mammals to be so 
low as to be discountable. As DP thrusters and subsea trenching 
operations are not expected to result in take of marine mammals, cable 
lay activities are not analyzed further in this document.

Marine Site Characterization Survey Activities

    Dominion would conduct marine site characterization surveys with 
the goal of ensuring the installation area is free of obstructions, 
installation equipment is accurately positioned, and that export cables 
(between the Project and shore) and inter-array cables (between the 
WTGs) are installed in the correct locations and to the appropriate 
depth below the seafloor. Marine site characterization surveys would be 
conducted 24 hours per day. These surveys would entail use of the 
following high resolution geophysical (HRG) equipment types:

     Subsea positioning to calculate position by measuring 
the range and bearing from a vessel-mounted transceiver to an 
acoustic transponder;
     Depth sounding (multibeam echosounder) to determine 
water depths and general bottom topography (currently estimated to 
range from approximately 6 to 26 m (20 to 85 ft) in depth);
     Parametric sub-bottom profiler to provide high-
resolution sub-bottom data laterally and vertically over all depth 
ranges; and
     Shallow penetration sub-bottom profiler (chirp) to map 
the near surface stratigraphy (top 0 to 5 m (0 to 16 ft) of soils 
below seabed).

    Table 2-2 in the IHA application identifies the representative 
survey equipment that may be used in support of planned site 
characterization survey activities. The deployment of HRG survey 
equipment, including the equipment planned for use during Dominion's 
planned activity, produces sound in the marine environment that has the 
potential to result in harassment of marine mammals. However, as sound 
propagation is dependent on several factors including operating mode, 
frequency and beam direction of the HRG equipment, the potential 
impacts to marine mammals from HRG equipment are driven by the 
specification of individual HRG sources.
    The specifications of the potential equipment planned for use 
during site characterization survey activities (Table 2-2 in the IHA 
application) were analyzed to determine whether these types of 
equipment would have the potential to result in harassment of marine 
mammals. Equipment that would be operated either at frequency ranges 
that fall outside the functional hearing ranges of marine mammals 
(e.g., above 180 kHz), that operate within marine mammal functional 
hearing ranges but have low sound source levels (e.g., a single pulse 
at less than 200 dB re re 1 [mu]Pa), or that operate with very narrow 
beam widths (e.g., a one degree beam width) are assumed to not have the 
potential to result in marine mammal harassment; therefore any sources 
planned for use by Dominion that falls into these categories (i.e., the 
SeaBat 7125 multibeam echosounder and Innomar SES-2000 parametric sub-
bottom profiler) were eliminated from further analysis. Equipment that 
does not fall into the above categories, but that is expected to 
produce sound in the marine environment that would attenuate to levels 
below the threshold for marine mammal harassment (i.e., 160 dB re 1 
[mu]Pa (rms) for intermittent sources) at very short distances (i.e., 
less than 25-m from the source) are also assumed to not have the 
potential to result in marine mammal harassment. Modeling of isopleth 
distances resulting from the remaining HRG sources proposed for use by 
Dominion (i.e., the PanGeo chirp and the Sonardyne Ranger 2 USBL) 
indicated that sound from these sources is expected to attenuate to 
levels below the threshold for marine mammal harassment at very short 
distances (i.e., less than 25-m) from the sound source.As it was 
determined that the likelihood of take occurring from all HRG equipment 
types proposed for use by Dominion would be so low as to be 
discountable, marine site characterization survey activities are not 
analyzed further in this document.

Construction Activities

    Dominion proposes to conduct pile driving activities to support 
installation of two WTG foundations. A monopile is a single, hollow 
cylinder fabricated from steel that is secured in the seabed. The 
monopiles proposed for the Project would have a 7.8 meter (m) (26 feet 
(ft)) diameter at the seafloor and 6 m (20 ft) diameter flange. The two 
monopiles would be 63 and 64 meters (207 and 210 ft) in length.
    The foundations would be constructed by driving the piles into the 
seabed with hydraulic hammers. 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. The pile driver operates by lifting 
a hammer inside the driver and dropping it onto a steel anvil. The 
anvil transmits the impulse into the top of the pile and the pile is 
forced into the sediment. Repeated blows drive the monopile to the 
desired depth, with the vertical travel of the pile decreasing

[[Page 14904]]

with each blow as greater soil resistance is built up from the contact 
between the pile surface and the sediment. Each blow typically results 
in a travel of several centimeters.
    The expected hammer energy required for pile driving would be 600 
kilojoules (kJ) though up to a maximum of 1,000 kJ may be required. 
Each pile is expected to take up to two hours to achieve the target 
penetration depth. Pile driving is expected to occur at a rate of 40 
blows per minute. A maximum of 3,419 strikes would be required to 
install the first foundation and 4,819 strikes would be required to 
install the second foundation, though the actual number of blows 
anticipated for the first and second foundations may ultimately be less 
(the difference in the number of strikes required for the two 
foundations is a result of variability in soil conditions between the 
two WTG locations). One monopile would be driven at a time and a 
maximum of one pile would be driven into the seabed per day.
    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. The acoustic energy travels into the water 
along different paths: From the top of the pile where the hammer hits, 
through the air, into the water; from the top of the pile, down the 
pile, radiating into the air while travelling down the pile, from air 
into water; from the top of the pile, down the pile, radiating directly 
into the water from the length of pile below the waterline; and, down 
the pile radiating into the seafloor, travelling through the seafloor 
and radiating back into the water. The underwater sound from pile 
driving may be received by biological receivers such as marine mammals 
through the water. Underwater sound produced during impact pile driving 
during installation of the WTGs could result in the incidental take of 
marine mammals.
    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 Activity

    Sections 4 and 5 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).
    All species that could potentially occur in the proposed project 
area are included in Table 4-1 of the IHA application. However, the 
temporal and/or spatial occurrence of several species listed in Table 
4-1 of the IHA application is such that take of these species is not 
expected to occur either because they have very low densities in the 
project area and/or are extralimital to the proposed project area. 
These are: The blue whale (Balaenoptera musculus), fin whale 
(Balaenoptera physalus), sei whale (Balaenoptera borealis), North 
Atlantic right whale (Eubalaena glacialis), humpback whale (Megaptera 
novaeangliae), minke whale (Balaenoptera acutorostrata), Bryde's whale 
(Balaenoptera edeni), sperm whale (Physeter macrocephalus), long-finned 
and short-finned pilot whale (Globicephala spp.), Cuvier's beaked whale 
(Ziphius cavirostris), four species of Mesoplodont beaked whale 
(Mesoplodon spp.), dwarf and pygmy sperm whale (Kogia sima and Kogia 
breviceps), northern bottlenose whale (Hyperoodon ampullatus), pygmy 
killer whale (Feresa attenuata), false killer whale (Pseudorca 
crassidens), melon-headed whale (Peponocephala electra), harbor 
porpoise (Phocoena phocoena), Risso's dolphin (Grampus griseus), 
striped dolphin (Stenella coeruleoalba), 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 harp seal (Pagophilus groenlandicus). As take of these 
species is not anticipated as a result of the proposed activities, 
these species are not analyzed further in this document.
    Table 1 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 (2019). 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 1 are the most 
recent available at the time of publication and are available in the 
2019 draft Atlantic SARs (Hayes et al., 2019), available online at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.

                     Table 1--Marine Mammals Known To Occur in the Project Area That May Be Affected by Dominion's Proposed Activity
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                                                           MMPA and ESA     Stock abundance
                                                             status;        (CV, Nmin, most       Predicted               Annual M/     Occurrence in
  Common name  (scientific name)           Stock         strategic (Y/N)    recent abundance   abundance (CV)   PBR \4\     SI \4\       project area
                                                               \1\            survey) \2\            \3\
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                                                               Toothed whales (Odontoceti)
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Atlantic white-sided dolphin.....  W. North Atlantic...  -; N             93,233(0.71;          37,180 (0.07)        544         26  Common.
(Lagenorhynchus acutus)..........                                          54,443; n/a).
Common dolphin...................  W. North Atlantic...  -; N             172,825 (0.21;        86,098 (0.12)      1,452        419  Common.
(Delphinus delphis)..............                                          145,216; 2011).

[[Page 14905]]

 
Atlantic spotted dolphin.........  W. North Atlantic...  -; N             39,921 (0.27;         55,436 (0.32)        320          0  Common.
(Stenella frontalis).............                                          32,032; 2012).
Bottlenose dolphin...............  W. North Atlantic,    -; N             62,851 (0.23;            \5\ 97,476        519         28  Common offshore.
(Tursiops truncatus).............   Offshore.                              51,914; 2011).              (0.06)
                                   W. North Atlantic,    -; N             3,751 (0.06; 2,353;  ..............         23     0-14.3  Common nearshore in
                                    Southern Migratory                     n/a).                                                      summer.
                                    Coastal.
Harbor porpoise..................  Gulf of Maine/Bay of  -; N             79,833 (0.32;         45,089 (0.12)        706        255  Common.
(Phocoena phocoena)..............   Fundy.                                 61,415; 2011).
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                                                                Earless seals (Phocidae)
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Gray seal \6\....................  W. North Atlantic...  -; N             27,131 (0.19;        ..............      1,389      5,410  Common.
(Halichoerus grypus).............                                          23,158; n/a).
Harbor seal......................  W. North Atlantic...  -; N             75,834 (0.15;        ..............      2,006        350  Common.
(Phoca vitulina).................                                          66,884; 2012).
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\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 2019 draft Atlantic SARs (Hayes et al., 2019).
\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 2019 SARs (Hayes et al., 2019).
\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, 2017, 2018) 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, 2017, 2018) produced a density model for bottlenose
  dolphins that does not differentiate between offshore and coastal stocks.
\6\ NMFS stock abundance estimate applies to U.S. population only, actual stock abundance is approximately 505,000.

    Below is a description of the species 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.

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 (Waring et 
al., 2016). 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).

Bottlenose Dolphin

    There are two distinct bottlenose dolphin morphotypes in the 
western North Atlantic: the coastal and offshore forms (Waring et al., 
2016). 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. The coastal morphotype is 
morphologically and genetically distinct from the larger, more robust 
morphotype that occupies habitats further offshore. Spatial 
distribution data, tag-telemetry studies, photo-ID studies and genetic 
studies demonstrate the existence of a distinct Southern Migratory 
stock of coastal bottlenose dolphins (Waring et al., 2014). The spatial 
distribution and migratory movements of the Southern Migratory Coastal 
stock are poorly understood and have been defined based on movement 
data from satellite-tag telemetry and photo-ID studies, and stable 
isotope studies. During the warm water months of July-August, the stock 
is presumed to occupy coastal waters north of Cape Lookout, North 
Carolina, to Assateague, Virginia, including Chesapeake Bay. During the 
remainder of the year (September-June), the stock migrates from 
southern North Carolina (south of Cape Lookout) to northern Florida 
(Hayes et al., 2017). The Western North Atlantic offshore stock and 
Southern Migratory Coastal stock may overlap to some degree in the 
project area (Hayes et al., 2017).

Common Dolphin

    The common dolphin is found world-wide in temperate to subtropical 
seas. In the North Atlantic, common dolphins are commonly 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 
(Waring et al., 2016).

[[Page 14906]]

Atlantic Spotted Dolphin

    Atlantic spotted dolphins are found in tropical and warm temperate 
waters ranging from southern New England, south to Gulf of Mexico and 
the Caribbean to Venezuela (Waring et al., 2014). This stock regularly 
occurs in continental shelf waters south of Cape Hatteras and in 
continental shelf edge and continental slope waters north of this 
region (Waring et al., 2014). There are two forms of this species, with 
the larger ecotype inhabiting the continental shelf and is usually 
found inside or near the 200 m isobaths (Waring et al., 2014).

Harbor Porpoise

    The Gulf of Maine/Bay of Fundy stock is the only stock that may be 
present in the project area. 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). They are seen from the coastline to deep waters 
(>1800 m; Westgate et al. 1998), although the majority of the 
population is found over the continental shelf (Waring et al., 2016). 
The main threat to the species is interactions with fisheries, with 
documented take in the U.S. northeast sink gillnet, mid-Atlantic 
gillnet, and northeast bottom trawl fisheries and in the Canadian 
herring weir fisheries (Waring 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 
(Waring et al., 2016). Haulout and pupping sites are located off 
Manomet, MA and the Isles of Shoals, ME, but generally do not occur in 
areas in southern New England (Waring et al., 2016).
    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. As of March, 2020 a total of 
3,050 reported strandings (of all species) had occurred, including 10 
strandings reported in Virginia. 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 thought to be from 
New Jersey to Labrador. Current population trends show that gray seal 
abundance is likely increasing in the U.S. Atlantic EEZ (Waring et al., 
2016). 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 (Waring et al., 2016). It is 
believed that recolonization by Canadian gray seals is the source of 
the U.S. population (Waring et al., 2016).
    As described above, elevated seal mortalities, including gray 
seals, have occurred from Maine to 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. 
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.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2016) 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. The functional groups and 
the associated frequencies are indicated below (note that these 
frequency ranges correspond to the range for the composite group, with 
the entire range not necessarily reflecting the capabilities of every 
species within that group):

     Low-frequency cetaceans (mysticetes): Generalized 
hearing is estimated to occur between approximately 7 Hertz (Hz) and 
35 kilohertz (kHz);
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): Generalized hearing is estimated to 
occur between approximately 150 Hz and 160 kHz;
     High-frequency cetaceans (porpoises, river dolphins, 
and members of the genera Kogia and Cephalorhynchus; including two 
members of the genus Lagenorhynchus, on the basis of recent 
echolocation data and genetic data): Generalized hearing is 
estimated to occur between approximately 275 Hz and 160 kHz; and
     Pinnipeds in water; Phocidae (true seals): Generalized 
hearing is estimated to occur between approximately 50 Hz to 86 kH.

    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. 
Fourteen marine mammal species (twelve cetacean and two pinniped (both 
phocid species) have the reasonable potential to co-occur with the 
proposed activities (see Table 3). Of the cetacean species that

[[Page 14907]]

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 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

[[Page 14908]]

the local environment or could form a distinctive signal that may 
affect marine mammals. Underwater ambient sound in the Atlantic Ocean 
offshore Virginia 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. The impulsive 
sound generated by impact hammers is characterized by rapid rise times 
and high peak levels.
    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.

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 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).

[[Page 14909]]

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 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

[[Page 14910]]

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; 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)

[[Page 14911]]

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, 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''), 
Dominion proposes to conduct pile driving. 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. Studies of underwater 
sound from pile driving finds that most of the acoustic

[[Page 14912]]

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. 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/

[[Page 14913]]

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 
environment within the Atlantic Ocean offshore Virginia 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 (i.e., two hours), 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 pile driving, and which have already been taken 
into account in the exposure analysis.

Anticipated Effects on Marine Mammal Habitat

    The proposed activities would not result in permanent impacts to 
habitats used directly by marine mammals, but 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, without 
any expected 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 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 in the 
project area 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 the Atlantic Ocean offshore 
Virginia and there are no known habitat areas of biological importance 
for marine mammals within the area that would be impacted. 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. Effects to habitat will not be discussed further in this 
document.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS'

[[Page 14914]]

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. 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) 
and 120 dB rms for continuous sources (e.g., vibratory driving). 
Dominion's proposed activity includes the use of impulsive sources 
(i.e., impact pile driving equipment) therefore use of the 160 dB re 1 
[mu]Pa (rms) threshold is applicable.
    Level A Harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). The 
components of Skipjack's proposed activity that may result in the take 
of marine mammals include the use of impulsive sources.
    These thresholds are provided in Table 2 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 2--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 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1[mu]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.


[[Page 14915]]

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, Dominion proposes to install two WTGs on 
monopile foundations. The WTG monopile foundations would each be 7.8-m 
in diameter. The expected hammer energy required to drive the two 
monopiles is 600 kJ, though a maximum potential hammer energy of 1,000 
kJ may be required. A bubble curtain would also be deployed to 
attenuate pile driving noise on at least one of the piles. Dominion 
performed acoustic modeling based on scenarios including 600 kJ and 
1,000 kJ hammer energy, and on attenuation levels of 15 dB, 10 dB, 6 dB 
and 0 dB achieved from the deployment of the bubble curtain.
    Modeling was performed using the software dBSea, a 3D model 
developed by Marshall Day Acoustics that is built by importing 
bathymetry data and placing noise sources in the environment. The dBSea 
model allows for the incorporation of several site-specific properties 
including sound speed profile, temperature, salinity, and current. 
Noise levels are calculated throughout the project area and displayed 
in 3D. The model also allows for the incorporation of several 
``solvers''. Two such ``solvers'' were incorporated in the modeling:
     dBSeaPE (Parabolic Equation Method): The dBSeaPE solver 
makes use of the parabolic equation method, a versatile and robust 
method of marching the sound field out in range from the sound source; 
and
     dBSeaRay (Ray Tracing Method): The dBSeaRay solver forms a 
solution by tracing rays from the source to the receiver. Many rays 
leave the source covering a range of angles, and the sound level at 
each point in the receiving field is calculated by coherently summing 
the components from each ray.
    The number of strikes per pile incorporated in the model were 3,419 
blows for the first foundation and 4,819 blows for the second 
foundation at a rate of 40 blows per minute (as described above, this 
represents a conservative estimate as the actual number of blows 
anticipated for the first and second foundations may ultimately be 
less). Source levels incorporated in the model were derived from data 
recorded at the Walney Extension Offshore Wind Farm located off the 
coast of England (NIRAS Consulting Ltd, 2017). Data from the Walney 
Extension project represents a suitable proxy for the proposed project 
as the piles at the Walney Extension project were the same diameter as 
those proposed for use in the CVOW project (i.e., 7.8-m) and water 
depth at the Walney Extension project was very similar to that at the 
CVOW project site (a depth of 28-m at the Walney Extension project 
compared to a depth of 25-m at the CVOW project site). Source levels 
derived from the Walney Extension project and used in the modeling are 
shown in Table 3.

Table 3--Source Levels Used in Modeling Pile Driving Noise From the CVOW
                                 Project
------------------------------------------------------------------------
          Hammer energy scenario               Source level at 1 meter
------------------------------------------------------------------------
600 kJ Hammer Energy......................  222 dBrms90.
                                            213 SEL.
                                            235 Peak.
1,000 kJ Hammer Energy....................  224 dBrms90.
                                            215 SEL.
                                            237 Peak.
------------------------------------------------------------------------

    Acoustic modeling was performed for scenarios including 600 kJ and 
1,000 kJ hammer energy. To be conservative, it was assumed for purposes 
of the exposure estimate that 1,000 kJ hammer energy would be required 
at all times during the driving of both piles. This represents a 
conservative assumption, as less energy may ultimately be required. 
Modeling scenarios included potential attenuation levels of 15 dB, 10 
dB, 6 dB and 0 dB achieved from the deployment of the attenuation 
system. Table 4 shows modeled isopleth distances to Level A and Level B 
harassment thresholds based on 1,000 kJ hammer energy and potential 
attenuation levels of 15 dB, 10 dB, 6 dB and 0 dB. Level A harassment 
isopleths vary based on marine mammal functional hearing groups. 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 cumulative sound exposure level 
(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., the 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 4--Modeled Radial Distances to Thresholds Corresponding to Level A and Level B Harassment From Pile
                                     Driving Based on 1,000 kJ Hammer Energy
----------------------------------------------------------------------------------------------------------------
                                       Radial distance to Level A harassment threshold (m) *          Radial
                                 ----------------------------------------------------------------   distance to
                                                                                                      Level B
                                  High frequency   Low frequency   Mid frequency      Phocid        harassment
      Attenuation scenario           cetaceans       cetaceans       cetaceans       pinnipeds     threshold (m)
                                    (peak SPL/      (peak SPL/      (peak SPL/     (underwater)  ---------------
                                      SELcum)         SELcum)         SELcum)       (peak SPL/      All marine
                                                                                      SELcum)         mammals
----------------------------------------------------------------------------------------------------------------
No attenuation..................       325/2,670       282/5,930         182/397       N/A/1,722           5,175
6 dB Reduction..................        80/1,277       N/A/3,830         N/A/252         N/A/567           3,580
10 dB Reduction.................         N/A/314       N/A/2,217         N/A/229         N/A/317           2,520
15 dB Reduction.................         N/A/233       N/A/1,277         N/A/124         N/A/236           1,370
----------------------------------------------------------------------------------------------------------------
* N/A indicates the distance to the threshold is so low it was undetectable in the modeling results.


[[Page 14916]]

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 habitat-based density models produced by the Duke University 
Marine Geospatial Ecology Laboratory (Roberts et al., 2016, 2017, 2018) 
represent the best available information regarding marine mammal 
densities in the proposed project area. The density data presented by 
Roberts et al. (2016, 2017, 2018) incorporates aerial and shipboard 
line-transect survey data from NMFS and other organizations and 
incorporates data from 8 physiographic and 16 dynamic oceanographic and 
biological covariates, and controls for the influence of sea state, 
group size, availability bias, and perception bias on the probability 
of making a sighting. These density models were originally developed 
for all cetacean taxa in the U.S. Atlantic (Roberts et al., 2016). In 
subsequent years, certain models have been updated on the basis of 
additional data as well as certain methodological improvements. The 
updated models incorporate additional sighting data, including 
sightings from the NOAA Atlantic Marine Assessment Program for 
Protected Species (AMAPPS) surveys from 2010-2014 (NEFSC & SEFSC, 2011, 
2012, 2014a, 2014b, 2015, 2016). More information, including the 
initial model results and supplementary information for each model, is 
available online at seamap.env.duke.edu/models/Duke-EC-GOM-2015/.
    Marine mammal density estimates in the project area (animals/km\2\) 
were obtained using the model results from Roberts et al. (2016, 2017, 
2018). While pile driving activities are planned for May, these 
activities could potentially occur any time between May and October. 
Average seasonal marine mammal densities were developed for each 
species and for each season when pile driving activities may occur 
using maximum monthly densities for each species, as reported by 
Roberts et al. (2016; 2017; 2018) (Densities from March through May 
were averaged for spring; June through August densities were averaged 
for summer; and September through November densities were averaged for 
fall). To be conservative, the highest average seasonal density for 
each species was then carried forward in the analysis (i.e., whichever 
of the three seasonal average densities was highest for each species 
was applied to the exposure estimate). The maximum seasonal density 
values used in the exposure estimates are shown in Table 7 below.

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate. In order to estimate 
the number of marine mammals predicted to be exposed to sound levels 
that would result in harassment, radial distances to predicted 
isopleths corresponding to harassment thresholds were calculated, as 
described above. The radial distances modeled based on scenarios of 100 
kJ hammer energy and 6 dB attenuation, 10 dB attenuation, 15 dB 
attenuation, and no attenuation (Table 4) were then used to calculate 
the areas around the pile predicted to be ensonified to sound levels 
that exceed relevant harassment thresholds.
    Marine mammal density values were overlaid on the ensonified zones 
to relevant thresholds within a geographic information system (GIS). 
The density values were multiplied by these zones, resulting in daily 
Level A and Level B harassment exposure estimates. These estimates were 
then multiplied by the number of days of pile driving activity (i.e., 
two) in order to estimate the number of marine mammals that would be 
exposed to pile driving noise above relevant thresholds for the entire 
project. The exposure numbers were rounded to the nearest whole 
individual.
    The following formula describes these steps:

Estimated Take = D x ZOI x (d)

Where:
D = average highest species density
ZOI = maximum ensonified area to relevant thresholds
d = number of days

    Dominion provided exposure estimates based on two days of pile 
driving for each scenario (i.e., no attenuation, 6 dB attenuation, 10 
dB attenuation and 15 dB attenuation). However, as Dominion has 
proposed potentially driving one pile with the attenuation system 
activated and the other pile without the attenuation system activated 
(described further under Proposed Mitigation, below), we assumed for 
the exposure estimate that one pile would be driven with no attenuation 
and the other pile would be driven with an attenuation system that 
would achieve an overall 6 dB reduction in pile driving sound. Thus we 
halved the exposure estimates provided for the 0 dB attenuation and 6 
dB attenuation scenarios to come up with exposure estimates for one day 
of pile driving for each scenario (i.e., one pile driven with no 
attenuation, and the other pile driven with 6 dB attenuation). We then 
combined these to come up with exposure estimates for the two piles. We 
note that an estimate of an overall 6 dB reduction from the attenuation 
system represents a conservative assumption, as the attenuation system 
planned for use is a double bubble curtain which may ultimately result 
in a greater level of attenuation than the assumed 6 dB (the 
attenuation system proposed for use is described further under Proposed 
Mitigation, below). Table 5 shows modeled exposures above the Level A 
harassment threshold for each of the two piles and both piles combined 
(note that modeling resulted in no takes by Level A harassment for any 
species, thus we do not propose to authorize any takes by Level A 
harassment and outputs in Table 5 are for illustrative purposes only). 
Table 6 shows modeled exposures above the Level B harassment threshold 
for each of the two piles and both piles combined. Table 7 shows 
maximum seasonal densities used in the take estimate, the number of 
takes proposed for authorization, and the total proposed takes as a 
percentage of population.

  Table 5--Modeled Exposures Above the Level A Harassment Threshold Estimated for Each Pile and for Both Piles
                                                    Combined
----------------------------------------------------------------------------------------------------------------
                                                                                   One pile with
                             Species                               One pile with       6 dB         Both piles
                                                                  no attenuation    attenuation      combined
----------------------------------------------------------------------------------------------------------------
Atlantic-spotted Dolphin........................................          0.0025           0.001          0.0035
White-sided Dolphin.............................................           0.005           0.002           0.007
Bottlenose Dolphin (W.N.A. Offshore)............................           0.059          0.0475          0.1065
Bottlenose Dolphin (W.N.A. Southern Coastal Migratory)..........           0.059          0.0475          0.1065
Risso's Dolphin.................................................               0               0               0
Common Dolphin..................................................           0.008           0.003           0.011

[[Page 14917]]

 
Pilot Whales....................................................               0               0               0
Sperm Whale.....................................................               0               0               0
Fin Whale.......................................................           0.256          0.1065          0.3625
Harbor Porpoise.................................................            0.17           0.039           0.209
Humpback Whale..................................................            0.11           0.046           0.156
Minke Whale.....................................................          0.1065          0.0445           0.151
North Atlantic Right Whale......................................          0.0845          0.0355            0.12
Sei Whale.......................................................           0.002          0.0005          0.0025
Harbor Seal.....................................................           0.086          0.0095          0.0955
Gray Seal.......................................................           0.086          0.0095          0.0955
----------------------------------------------------------------------------------------------------------------


  Table 6--Modeled Exposures Above the Level B Harassment Threshold Estimated for Each Pile and for Both Piles
                                                    Combined
----------------------------------------------------------------------------------------------------------------
                                                                                   One pile with    Both piles
                            Species *                              One pile with       6 dB          combined
                                                                  no attenuation    attenuation      (rounded)
----------------------------------------------------------------------------------------------------------------
Common dolphin..................................................            1.34            0.45               2
Atlantic-spotted dolphin........................................            0.43            0.14               1
Atlantic white-sided dolphin....................................            0.86            0.29               1
Bottlenose dolphin (W.N.A. Offshore)............................           20.08           13.49              34
Bottlenose dolphin (W.N.A. Southern Coastal Migratory)..........           20.08           13.49              34
Harbor porpoise.................................................            0.64            0.22               1
Harbor seal.....................................................            0.78            0.26               1
Gray seal.......................................................            0.78            0.26               1
----------------------------------------------------------------------------------------------------------------
* All species potentially occurring in the project area were modeled; only species with at least one exposure
  above the Level B harassment threshold that were carried forward in the take analysis are shown.


      Table 7--Marine Mammal Densities, Numbers of Potential Incidental Take of Marine Mammals Proposed for
                         Authorization and Proposed Takes as a Percentage of Population
----------------------------------------------------------------------------------------------------------------
                                                     Estimated                                    Total proposed
                                      Density     takes by Level  Proposed takes    Total takes     takes as a
             Species               (animals/100    B harassment     by Level B     proposed for    percentage of
                                      km \2\)           \1\         harassment     authorization  population \2\
----------------------------------------------------------------------------------------------------------------
Common dolphin \3\..............           1.591               2              39              39             0.0
Atlantic white-sided dolphin \3\           1.018               1              40              40             0.1
Bottlenose dolphin (W. N.                 23.861              34              34              34             0.9
 Atlantic Coastal Migratory) \4\
Bottlenose dolphin (W. N.                 23.861              34              34              34             0.1
 Atlantic Offshore \ 4\.........
Atlantic spotted dolphin \3\....           0.508               1             100             100             0.2
Harbor porpoise \3\.............           0.760               1               4               4             0.0
Gray seal \4\...................           0.925               1               1               1             0.0
Harbor seal \4\.................           0.925               1               1               1             0.0
----------------------------------------------------------------------------------------------------------------
\1\ Estimated takes based on a scenario of 1,000 kJ hammer energy and one pile driven with 6 dB attenuation and
  the other pile driven with no attenuation.
\2\ Calculations of percentage of stock taken are based on the best available abundance estimate as shown in
  Table 1. In most cases the best available abundance estimate is provided by Roberts et al. (2016, 2017, 2018),
  when available, to maintain consistency with density estimates derived from Roberts et al. (2016, 2017, 2018).
\3\ Proposed number of authorized takes (Level B harassment only) for these species has been increased from the
  estimated take number to mean group size. Sources for group size estimates are as follows: Atlantic white-
  sided dolphin: Cipriano (2018); common dolphin: Palka et al. (2015); harbor porpoise: Palka et al. (2015);
  Atlantic spotted dolphin: Herzing and Perrin (2018).
\4\ Roberts et al. (2016, 2017, 2018) produced a single density model for all bottlenose dolphins and did not
  differentiate by bottlenose dolphin stocks, and produced a single density model for all seals and did not
  differentiate between seal species. Hence, the density value is the same for both stocks of bottlenose dolphin
  stocks that may be present and for both seal species.

    Modeling results predicted no takes by Level A harassment for any 
marine mammal species (based on both SELcum and peak SPL) 
(See Table 5). NMFS has therefore determined that the likelihood of 
take of marine mammals in the form of Level A harassment occurring as a 
result of the proposed activity is so low as to be discountable, and we 
do not propose to authorize the take by Level A harassment of any 
marine mammals.
    Using the take methodology approach described above, the resulting 
take estimates for Atlantic white-sided dolphin, common dolphin, 
spotted dolphin and harbor porpoise were less than the average group 
sizes estimated for these species. However, information on the life 
histories of these species indicates they are likely to be encountered 
in groups, therefore it is reasonable to conservatively assume that one 
group of each of these species will be taken during the proposed

[[Page 14918]]

activity. We therefore propose to authorize the take of the average 
group size for these species to account for the possibility that a 
group of any of these species or stocks is taken by the proposed 
activities (Table 7).
    Roberts et al. (2016, 2017, 2018) produced a single density model 
for all bottlenose dolphins and did not differentiate by bottlenose 
dolphin stocks. The Western North Atlantic southern migratory coastal 
stock occurs in coastal waters from the shoreline to approximately the 
20-m isobath (Hayes et al. 2019). The water depth at the WTG 
installation location is 25 m. As 20-m represents an approximate depth 
limit for the coastal stock, both stocks have the potential to occur in 
the project area. Therefore we propose to authorize take for both 
stocks. The take calculation methodology described above resulted in an 
estimate of 34 bottlenose dolphin takes. We have concluded that since 
either stock may be present it is possible that all modeled takes may 
accrue to either of the stocks and we therefore propose to authorize 34 
takes from both stocks that may be present. We are therefore proposing 
to authorize twice the amount of takes that the exposure modeling 
predicts for bottlenose dolphins.
    Similar to bottlenose dolphins, Roberts et al. (2018) produced 
density models for all seals and did not differentiate by seal species. 
Because the seasonality of, and habitat use by, gray seals roughly 
overlaps with that of harbor seals in the project area, it is possible 
that modeled seal takes could occur to either species. The take 
calculation methodology described above resulted in an estimate of one 
seal take. As the one modeled seal take may accrue to either seal 
species we therefore propose to authorize one take from both seal 
species that may be present. We are therefore proposing to authorize 
twice the amount of takes that the exposure modeling predicts for seal 
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, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The mitigation measures described below are consistent with those 
required and successfully implemented under previous incidental take 
authorizations issued in association with in-water construction 
activities. 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 below, Dominion 
would conduct briefings for construction supervisors and crews, the 
marine mammal monitoring teams, and Dominion 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 from November 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 (Roberts et al., 
2017), the highest densities of right whales in the project area are 
expected during the months of November 1 through April when right 
whales are migrating. This restriction would greatly reduce the 
potential for right whale exposure to pile driving noise associated 
with the proposed project.

Pre-Clearance, Exclusion and Monitoring Zones

    Dominion would use PSOs to establish a 1,750-m exclusion zone (EZ) 
around the pile driving equipment to ensure this zone is 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 while we acknowledge that porpoises or seals 
may not be detected at this distance, the proposed 1,750-m EZ is 
significantly larger than modeled distances to isopleth distances 
corresponding to Level A harassment (based on peak SPL) for all marine 
mammal functional hearing groups (Table 4). The EZ for North Atlantic 
right whales would effectively extend beyond 1,750-m to as far as PSOs 
are able to see (i.e., a North Atlantic right whale observed at any 
distance from the pile, regardless of the whale's distance from the 
pile, would trigger further mitigation action (either delay or 
shutdown)).
    In addition to the EZ, PSOs would observe a monitoring zone that 
would correspond with the modeled distance to the Level B harassment 
isopleth (3,580 m) during pile driving activities. PSOs would record 
information on marine mammals observed within the monitoring zone, 
including species, observed behavior, and estimates of number of marine 
mammals exposed to pile driving noise within the Level B harassment 
zone. Marine mammals

[[Page 14919]]

observed within the monitoring zone but outside the EZs would not 
trigger any mitigation action. All distances are the radius from the 
center of the pile.

            Table 8--Proposed Exclusion and Monitoring Zones
------------------------------------------------------------------------
              Exclusion zone                       Monitoring zone
------------------------------------------------------------------------
1,750 m *.................................  3,580 m
------------------------------------------------------------------------
* A North Atlantic right whale observed at any distance from the pile
  would trigger delay or shutdown of pile driving.

    If a marine mammal is observed approaching or entering the relevant 
EZ prior to the start of pile driving operations, pile driving activity 
would be delayed until either the marine mammal has voluntarily left 
the respective EZ and been visually confirmed beyond that zone, or, 15 
minutes have elapsed without re-detection of the animal in the case of 
delphinids and pinnipeds or 30 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 EZ would be 
monitored for 30 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 zones clear of marine mammals. Marine 
mammals observed within a EZ would be allowed to remain in the 
clearance zone (i.e., must leave of their own volition), and their 
behavior would be monitored and documented. The EZs 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.

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. 
Dominion 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 30 second waiting period. The soft 
start process would be conducted a total of three times prior to 
driving each pile (e.g., three strikes followed by a 30 second delay, 
then three additional single strikes followed by a 30 second delay, 
then a final set of three strikes followed by an additional 30 second 
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 EZs after pile driving has begun, the PSO would request a 
temporary cessation of pile driving. Dominion has proposed that, when 
called for by a PSO, shutdown of pile driving would be implemented when 
practicable. However, there may be instances where a shutdown is not 
practicable, as any significant stoppage of pile driving progress can 
allow for displaced sediments along the piling surface areas to 
consolidate and bind, potentially resulting in a situation where a 
piling is permanently bound in a partially driven position. If a 
shutdown is called for before a pile has been driven to a sufficient 
depth to allow for pile stability, then for safety reasons the pile 
would need to be driven to a sufficient depth to allow for stability 
and a shutdown would not be practicable until after that depth was 
reached. We therefore propose that shutdown would be implemented when 
practicable.
    If shutdown is called for by a PSO, and Dominion determines a 
shutdown to be technically practicable, pile driving would be halted 
immediately. After shutdown, pile driving may be initiated once all EZs 
are clear of marine mammals for the minimum species-specific time 
periods, or, if required to maintain installation feasibility. For 
North Atlantic right whales, shutdown would occur when a right whale is 
observed by PSOs at any distance, and a shutdown zone of 1,750 m would 
be implemented for all other species (Table 8).

Noise Attenuation System

    The Project would utilize an attenuation system in order to reduce 
underwater noise from pile driving during the driving of at least one 
pile. Bubble curtains are used to reduce acoustic energy emissions from 
high-amplitude sources and are generated by releasing air through 
multiple small holes drilled in a hose or manifold deployed on the 
seabed near the source. The resulting curtain of air bubbles in the 
water attenuates sound waves propagating through the curtain. The sound 
attenuating effect of the noise mitigation system bubble curtain or air 
bubbles in water is caused by: (i) Sound scattering on air bubbles 
(resonance effect) and (ii) (specular) reflection at the transition 
between water layer with and without bubbles (air water mixture; 
impedance leap). Use of a ``double bubble curtain'' entails two 
concentric rings of bubbles around the pile and can achieve greater 
levels of attenuation than the use of a single bubble curtain. A double 
bubble curtain would be deployed to reduce sound during pile driving 
activities during the driving of at least one pile.
    Dominion has proposed driving one pile with the double bubble 
curtain activated and the other pile without the double bubble curtain 
activated with the goal of gathering in situ data on the effectiveness 
of the double bubble curtain via hydroacoustic monitoring during the 
driving of both piles. This effort would be supported by the Bureau of 
Ocean Energy Management (BOEM) Real-time Opportunity for Development 
Environmental Observations (RODEO) program, which aims to collect real-
time measurements of the construction and operation activities from the 
first offshore wind facilities in the United States to allow for more 
accurate assessments of actual environmental effects and to inform 
development of appropriate mitigation measures.
    The bubble curtains would distribute air bubbles around 100 percent 
of the piling perimeter for the full depth of the water column. The 
lowest bubble ring would be in contact with the mudline for the full 
circumference of the ring, and the weights attached to the bottom ring 
would ensure 100 percent mudline contact. No parts of the ring or other 
objects would prevent full mudline contact. Air flow to the bubblers 
would be balanced around the circumference of the pile.

Visibility Requirements

    All pile driving would be initiated during daylight hours, no 
earlier than 30 minutes after sunrise and no later than 30 minutes 
before sunset. Pile driving would not be initiated at night, or, when 
the full extent of the 1,750 m EZ cannot be confirmed to be clear of 
marine mammals, as determined by the lead PSO on duty. The EZ may only 
be declared clear, and pile driving initiated, when the full extent of 
the 1,750 m EZ is visible (i.e., when not obscured by dark, rain, fog, 
etc.) for a full 30 minutes prior to pile driving. Dominion would 
attempt to complete all pile driving in daylight; pile driving may 
continue after dark only when the installation of the same pile began 
during daylight when the Exclusion

[[Page 14920]]

Zone was fully visible for at least 30 minutes, and only in 
extraordinary circumstances when it must proceed for human safety or 
installation feasibility reasons as determined by the lead engineer.

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 EZ will not result in delay of pile driving; that pile 
segment may be completed without cessation, unless the marine mammal 
approaches or enters the EZ, 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, as long as the 
time elapsed between uses of the pile driving equipment is no more than 
30 minutes.
    The following additional measures would apply to visual monitoring:
    (1) A minimum of two PSOs would be on duty at all times during pile 
driving and removal activity;
    (2) Monitoring would be conducted by qualified, trained PSOs. PSOs 
would be stationed at the highest practical vantage point on the pile 
installation vessel;
    (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 would be conducted from 30 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 would have no other construction-related tasks while 
conducting monitoring; and
    (6) PSOs would 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;
     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.

    PSOs employed by Dominion 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 must travel at 10 knots (18.5 km/hr) or 
less within any designated Dynamic Management Area (DMA) or Seasonal 
Management Area for North Atlantic right whales;
     All vessel operators must 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 vessels must maintain a separation distance of 500 
m (1640 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 (1640 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 must 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 must 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 must maintain a separation distance of 50 m 
(164 ft) or greater from any sighted pinniped; and
     All vessels underway must 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.

    Dominion 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.
    The proposed mitigation measures are designed to avoid the already 
low potential for injury in addition to some instances of Level B 
harassment, and to minimize the potential for vessel strikes. Further, 
we believe the proposed mitigation measures are practicable for 
Dominion to implement. There are no known marine mammal rookeries or 
mating or calving grounds in the project area that would otherwise 
potentially warrant increased mitigation measures for marine mammals or 
their habitat (or both).
    We have carefully evaluated Dominion'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

[[Page 14921]]

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 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.

Proposed Monitoring Measures

    Dominion 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 be stationed on the pile installation vessel. 
The observer platform would be elevated approximately 40-m above the 
sea surface. Dominion estimates that at this height a PSO with minimum 
7x50 binoculars would be able to monitor a first reticule distance of 
approximately 3.2 miles from the sound source. PSOs would monitor the 
EZ and the Level B harassment zone at all times and would document any 
marine mammals observed within these zones, to the extent practicable. 
PSOs would conduct monitoring before, during, and after pile driving 
and removal, with observers located at the best practicable vantage 
points.
    Dominion would implement the following monitoring procedures:

     A minimum of two PSOs will maintain watch at all times 
when pile driving is underway;
     PSOs would be located at the best possible vantage 
point(s) on the pile installation vessel to ensure that they are 
able to observe the entire EZ and as much of the monitoring 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 range 
finders as well as a digital single-lens reflex 35mm camera;
     Position data will be recorded using hand-held or 
vessel based global positioning system (GPS) units for each 
sighting;
     If the EZ is obscured by fog or poor lighting 
conditions, pile driving will not be initiated until the EZ is fully 
visible. Should such conditions arise while pile driving is 
underway, the activity would be halted when practicable, as 
described above; and
     The EZ and monitoring zone will be monitored for the 
presence of marine mammals before, during, and after all pile 
driving activity.

    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 Dominion.

Data Collection

    We require that observers use standardized data forms. Among other 
pieces of information, Dominion 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:

     Dates and times (begin and end) of all marine mammal 
monitoring.
     Construction activities occurring during each daily 
observation period, including how many and what type of piles were 
driven or removed and by what method (i.e., impact or vibratory).
     Weather parameters and water conditions during each 
monitoring period (e.g., wind speed, percent cover, visibility, sea 
state).
     The number of marine mammals observed, by species, 
relative to the pile location and if pile driving or removal was 
occurring at time of sighting.
     Age and sex class, if possible, of all marine mammals 
observed.
     PSO locations during marine mammal monitoring.
     Distances and bearings of each marine mammal observed 
to the pile being driven or removed for each sighting (if pile 
driving or removal was occurring at time of sighting).
     Description of any marine mammal behavior patterns 
during observation, including direction of travel and estimated time 
spent within the Level A and Level B harassment zones while the 
source was active.
     Number of individuals of each species (differentiated 
by month as appropriate) detected within the monitoring zone, and 
estimates of number of marine mammals taken, by species (a 
correction factor may be applied to total take numbers, as 
appropriate).
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting behavior of the animal, 
if any.
     Description of attempts to distinguish between the 
number of individual animals taken and the number of incidences of 
take, such as ability to track groups or individuals.
     An extrapolation of the estimated takes by Level B 
harassment based on the number of observed exposures within the 
Level B harassment zone and the percentage of the Level B harassment 
zone that was not visible.

Submit all PSO datasheets and/or raw sighting data (in a separate 
file from the Final Report referenced immediately above).

    Dominion would note behavioral observations, to the extent 
practicable, if a marine mammal has remained in the area during 
construction activities.

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

[[Page 14922]]

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). A final report must be submitted within 30 days following 
resolution of comments on the draft report.
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the IHA-holder shall report 
the incident to the Office of Protected Resources (OPR) (301-427-8401), 
NMFS and to the Mid-Atlantic regional stranding coordinator as soon as 
feasible. The report must include the following information:

     Time, date, and location (latitude/longitude) of the 
first discovery (and updated location information if known and 
applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition 
if the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    Pile driving and removal 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 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 our analyses apply to all the 
species listed in Table 1, given that the anticipated effects of the 
proposed project on different marine mammal species and stocks are 
expected to be similar in nature.
    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 auditory injury even in the absence of the proposed 
mitigation measures, with no species predicted to experience Level A 
harassment. In addition, the already limited potential for injury is 
expected to be minimized through implementation of the proposed 
mitigation measures including soft start and the implementation of EZs 
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. 
No Level A harassment of any marine mammal stocks are anticipated or 
proposed for authorization.
    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. Instances of more severe behavioral harassment are 
expected to be minimized by proposed mitigation and monitoring 
measures. 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 
disturbed 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 activities 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, and there are 
no rookeries, mating areas, or calving areas known to be biologically 
important to marine mammals within the proposed project area. The area 
is part of a biologically important migratory area for North Atlantic 
right whales; however, seasonal restrictions on pile driving activity, 
which would restrict pile driving to times of year when right whales 
are least likely to be migrating through the project area, would 
minimize the potential for the activity to impact right whale 
migration.
    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

[[Page 14923]]

to breeding, feeding, sheltering, resting, or migration are not 
expected, nor are shifts in habitat use, distribution, or foraging 
success. Serious injury or mortality as a result of the proposed 
activities would not be expected even in the absence of the proposed 
mitigation and monitoring measures, and no serious injury or mortality 
of any marine mammal stocks are anticipated or proposed for 
authorization. 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, gray and harbor seals are experiencing ongoing 
UMEs. 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). No injury, serious injury or mortality is 
expected or proposed for authorization, and Level B harassment of gray 
and harbor 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 gray and harbor seals 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 Level A harassment, serious injury or mortality 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;
     Total proposed authorized takes as a percentage of 
population are low for all species and stocks (i.e., less than one 
percent of all 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, and authorized activities would 
be limited to times of year when potential impacts to migration 
would not be expected;
     The proposed mitigation measures, including visual 
monitoring, exclusion and monitoring zones, a bubble curtain used on 
at least one pile, 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 seven marine mammal 
stocks. The total amount of taking proposed for authorization is less 
than one-third of the best available population abundance estimate for 
all stocks (Table 7), which 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

    Section 7(a)(2) of the Endangered Species Act of 1973 (16 U.S.C. 
1531 et seq.) requires that each Federal agency insure that any action 
it authorizes, funds, or carries out is not likely to jeopardize the 
continued existence of any endangered or threatened species or result 
in the destruction or adverse modification of designated critical 
habitat. To ensure ESA compliance for the issuance of IHAs, NMFS 
consults internally whenever we propose to authorize take for 
endangered or threatened species. No incidental take of ESA-listed 
species is proposed for authorization or expected to result from this 
activity. Therefore, NMFS has determined that formal consultation under 
section 7 of the ESA is not required for this action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to Dominion for conducting pile driving activity offshore 
of Virginia, from May 1, 2020 through October 31, 2020, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. A draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this Notice of Proposed IHA for Dominion's proposed 
activity. We also request at this time comment on the potential Renewal 
of this proposed IHA as described in the paragraph below. Please 
include with your comments any supporting data or literature citations 
to help inform decisions on the request for this IHA or a subsequent 
Renewal IHA.
    On a case-by-case basis, NMFS may issue a one-year Renewal IHA 
following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical, or nearly identical, activities as described in the 
Specified Activities section of this notice is planned or (2) the 
activities as described in the Specified Activities section of this 
notice would not be completed by the time the IHA expires and a Renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this

[[Page 14924]]

notice, provided all of the following conditions are met:

     A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that the 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes 
so minor (e.g., reduction in pile size) that the changes do not 
affect the previous analyses, mitigation and monitoring 
requirements, or take estimates (with the exception of reducing the 
type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for Renewal, the status of 
the affected species or stocks, and any other pertinent information, 
NMFS determines that there are no more than minor changes in the 
activities, the mitigation and monitoring measures will remain the 
same and appropriate, and the findings in the initial IHA remain 
valid.

    Dated: March 10, 2020.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2020-05281 Filed 3-13-20; 8:45 am]
 BILLING CODE 3510-22-P