[Federal Register Volume 83, Number 112 (Monday, June 11, 2018)]
[Notices]
[Pages 26968-26991]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-12471]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG108


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Unexploded Ordnance Investigation 
Survey off the Coast 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 unexploded ordnance (UXO) 
investigation surveys off the coast of Virginia as part of site 
characterization surveys in the area of the Research Lease of Submerged 
Lands for Renewable Energy Development on the Outer Continental Shelf 
(OCS-A 0497) (Lease Area) and coastal waters where a cable route 
corridor will be established. 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 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 July 11, 
2018.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent to <a href="/cdn-cgi/l/email-protection#2b627f7b0572445e454c4042456b45444a4a054c445d"><span class="__cf_email__" data-cfemail="357c61651b6c5a405b525e5c5b755b5a54541b525a43">[email protected]</span></a>.
    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: Dale Youngkin, 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

    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 
authorization is provided to the public for review.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth.
    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as an 
impact

[[Page 26969]]

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.
    The MMPA states that the term ``take'' means to harass, hunt, 
capture, or kill, or attempt to harass, hunt, capture, or kill any 
marine mammal.
    Except with respect to certain activities not pertinent here, 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).

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to potential impacts 
on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (incidental harassment authorizations with 
no anticipated serious injury or mortality) of the Companion Manual for 
NOAA Administrative Order 216-6A, which do not individually or 
cumulatively have the potential for significant impacts on the quality 
of the human environment and for which we have not identified any 
extraordinary circumstances that would preclude this categorical 
exclusion. Accordingly, NMFS has preliminarily determined that the 
issuance of the proposed IHA qualifies to be categorically excluded 
from further NEPA review. We will review all comments submitted in 
response to this notice prior to concluding our NEPA process or making 
a final decision on the IHA request.

Summary of Request

    On March 7, 2018, NMFS received a request from Dominion for an IHA 
to take marine mammals incidental to high resolution geophysical (HRG) 
surveys off the coast of Virginia. The purpose of these surveys are to 
acquire data regarding the potential presence of UXO within the 
proposed construction and operational footprints of the Coastal 
Virginia Offshore Wind (CVOW) Project Area in the Lease Area and export 
cable route construction corridor (Survey Area). A revised application 
was received on April 26, 2018. NMFS deemed that request to be adequate 
and complete. Dominion's request is for take of nine marine mammal 
species by Level B harassment. Neither Dominion nor NMFS expects 
injury, 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

    Dominion proposes to conduct marine site characterization surveys 
including HRG surveys to search for UXO in the marine environment of 
the approximately 2,135-acre Lease Area located offshore of Virginia 
(see Figure 1-1 in the IHA application). Additionally, an export cable 
route will be established between the Lease Area and Virginia Beach, 
identified as the Export Cable Route Area (see Figure 1 in the IHA 
application). See the IHA application for further information. The 
survey area consists of two 1-kilometer (km) X 1-km turbine position 
locations, a 2 km by 300 meter (m) Inter-array cable route connecting 
the two turbine position locations, and a 43-km X 300 m Export Corridor 
Route. For the purpose of this IHA, the survey area is designated as 
the Lease Area and cable route corridors. Water depths across the Lease 
Area are estimated to range from approximately 8 to 40 m (26 to 131 
feet (ft)) while the cable route corridors will extend to shallow water 
areas near landfall locations. Surveys would begin no earlier than 
August 1, 2018 and are anticipated to last for up to three months.
    The purpose of the marine site characterization surveys are to 
acquire data regarding the potential presence of UXO within the 
proposed construction and operational footprints of the CVOW Project 
Area (i.e., export cable construction corridor, inter-array cable area, 
and wind turbine positions) in accordance with the Bureau of Ocean 
Energy Management (BOEM) guidelines for archaeology surveys as well as 
geophysical activities. No removal of ordnance would be conducted as a 
part of the activities. Underwater sound resulting from Dominion's 
proposed HRG surveys for UXO have the potential to result in incidental 
take of marine mammals in the form of harassment.

Dates and Duration

    Surveys will last for approximately three months and are 
anticipated to commence no earlier than August 1, 2018. This schedule 
is based on 24-hour operations and includes potential down time due to 
inclement weather. Based on 24-hour operations, the estimated duration 
of the HRG survey activities would be approximately 60 days for the 
export cable route corridor and approximately 15 days each for the 
inter-array cable route and wind turbine positions.

Specific Geographic Region

    Dominion's survey activities will occur in the approximately 2,135-
acre Research Lease Area located off the coast of Virginia (see Figure 
1 in the IHA application). Additionally, a cable route corridor would 
be surveyed between the Lease Area and the coast of Virginia. The cable 
route corridor to be surveyed is anticipated to be 300 m wide and 43 km 
long. The wind turbine positions to be surveyed are 2 approximately 1 
km X 1 km square areas connected by an inter-array cable route that is 
300 m wide and 2 km in length.

Detailed Description of the Specified Activities

    Dominion's proposed marine site characterization surveys include 
HRG survey activities. These activities are described below.

HRG Survey Activities

    The HRG survey activities proposed by Dominion would include the 
following:
    <bullet> Depth sounding (multibeam echosounder) to determine water 
depths and general bottom topography (currently estimated to range from 
approximately 8 to 40 m (26 to 131 ft) in depth);
    <bullet> Magnetic intensity measurements for detecting local 
variations in regional magnetic field from geological strata and 
potential ferrous objects on and below the bottom;
    <bullet> Seafloor imaging (sidescan sonar survey) for seabed 
sediment classification purposes, to identify acoustic targets resting 
on the bottom or that are partially buried;
    <bullet> Shallow penetration sub-bottom profiler (pinger/chirp) to 
map the near surface stratigraphy (top 0 to 5 m (0 to 16 ft) of soils 
below seabed); and
    <bullet> Medium penetration sub-bottom profiler (sparker) to map 
deeper subsurface stratigraphy as needed (soils down to 20 m (66 ft) 
below seabed).
    Table 1 identifies the representative survey equipment that may be 
used in support of planned HRG survey activities. The make and model of 
the listed HRG equipment will vary depending on availability but will 
be finalized as part of the survey

[[Page 26970]]

preparations and contract negotiations with the survey contractor. The 
final selection of the survey equipment will be confirmed prior to the 
start of the HRG survey program. Any survey equipment selected would 
have characteristics similar to the systems described below, if 
different.

                                          Table 1--Summary of HRG Survey Equipment Proposed for Use by Dominion
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                   Representative HRG        Operating                              Peak source level    Beamwidth      Pulse duration
           HRG system               survey equipment        frequencies      RMS source level \1\          \1\            (degree)        (millisec)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Subsea Positioning/USBL.........  Sonardyne Ranger 2   35-50kHz............  188 dBrms...........  200 dBPeak.........          180  1.
                                   USBL.
Sidescan Sonar..................  Klein 300H Sidescan  445/900 kHz *.......  242 dBrms...........  226 dBPeak.........          0.2  0.0025 to 0.4.
                                   Sonar.
Pinger/Chirper..................  GeoPulse Sub-Bottom  1.5-19 kHz..........  208 dBrms...........  223.5 dBPeak.......           55  0.1 to 1.
                                   Profiler.
Sparker.........................  Geo-Source 600/800.  50 Hz-5 kHz.........  221/217 dBrms.......  222/223 dBPeak.....          110  0.8.
Multibeam Sonar.................  SeaBat 7125........  200/400 kHz *.......  221 dBrms...........  220 dBPeak.........            2  2 to 6.
Medium Sub-Bottom Profiler......  Innomar 100........  85-115 kHz..........  243 dBrms...........  250 dBPeak.........            1  0.07 to 2.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Source levels reported by manufacturer.
* Operating frequencies are above all relevant marine mammal hearing thresholds, so are not assessed in this IHA.

    The HRG survey activities would be supported by up to two vessels. 
Assuming a maximum survey track line to fully cover the survey area, 
the assigned vessels will be sufficient in size to accomplish the 
survey goals in specific survey areas and will be capable of 
maintaining both the required course and survey speed of approximately 
4.0 nautical miles per hour (mph) (knot (kn)) while transiting survey 
lines.
    To minimize cost, the duration of survey activities, and the period 
of potential impact on marine species while surveying, Dominion has 
proposed that HRG survey operations would be conducted continuously 24 
hours per day. Based on 24-hour operations, the estimated duration of 
the HRG survey activities would be approximately three months 
(including estimated weather down time) including 60 survey days in the 
export cable route and 15 survey days each in the inter-array cable 
route corridor and wind turbine positions.
    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. Based on the frequency ranges and source levels of 
the potential equipment planned to be used in support of HRG survey 
activities (Table 1) the survey activities that have the potential to 
cause Level B harassment to marine mammals include the noise produced 
by the 800 kilojoule (kJ) Geo-Source sparker, the GeoPulse sub-bottom 
profiler (pinger), and the Innomar Medium 100 sub-bottom profiler. We 
note here that the operating frequencies for all but the Innomar Medium 
100 sub-bottom profiler are in the best hearing range for all marine 
mammal species that may potentially occur in the project area. However, 
the Innomar Medium 100 sub-bottom profiler operating frequencies are 
outside of the best hearing range for low-frequency (LF) cetacean 
species (refer to Marine Mammal subsection below for more detail on 
marine mammal hearing groups). Level A harassment may occur at 
distances from the Innomar 100 sub-bottom profiler solely for high-
frequency (HF) cetaceans (harbor porpoise), though it is very unlikely 
to occur due to the one degree beam width. For the LF and mid-frequency 
(MF) cetaceans, Level A harassment could only potentially occur so 
close to the HRG source such that Level A harassment is not 
anticipated, especially in consideration of the hearing ranges for LF 
cetaceans and with implementation of monitoring and mitigation measures 
(described in more detail in the ``Estimated Take'' and ``Proposed 
Mitigation'' sections below). 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 3 and 4 of Dominion's IHA application summarize available 
information regarding status and trends, distribution and habitat 
preferences, and behavior and life history, of the potentially affected 
marine mammal species. Additional information regarding population 
trends and threats may be found in NMFS's Stock Assessment Reports 
(SAR; www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these 
species (e.g., physical and behavioral descriptions) may be found on 
NMFS's website (www.fisheries.noaa.gov/species-directory).
    Table 2 lists all species with expected potential for occurrence in 
the survey area and summarizes information related to the population or 
stock, including regulatory status under the MMPA and Endangered 
Species Act (ESA) and potential biological removal (PBR), where known. 
For taxonomy, we follow Committee on Taxonomy (2017). PBR is defined by 
the MMPA as the maximum number of animals, not including natural 
mortalities, that may be removed from a marine mammal stock while 
allowing that stock to reach or maintain its optimum sustainable 
population (as described in NMFS's SARs). While no mortality is 
anticipated or authorized here, PBR is included here as gross 
indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. 2017 draft SARs (e.g., Hayes et al., 2018). All values 
presented in Table 2 are the most recent available at the time of 
publication and are available in the 2017 draft SARs (Hayes et al., 
2018).

[[Page 26971]]



                      Table 2--Marine Mammals With Potential Occurrence in the Survey Area
----------------------------------------------------------------------------------------------------------------
                                                  NMFS MMPA
                                                   and ESA     Stock abundance                 Occurrence and
         Common name                 Stock         status;      (CV,Nmin) \2\    PBR \3\   seasonality in the NW
                                                  strategic                                     Atlantic OCS
                                                  (Y/N) \1\
----------------------------------------------------------------------------------------------------------------
                                           Toothed whales (Odontoceti)
----------------------------------------------------------------------------------------------------------------
Atlantic white-sided dolphin   W North Atlantic  -; N         48,819 (0.61;           304  rare.
 (Lagenorhynchus acutus).                                      30,403).
Atlantic spotted dolphin       W North Atlantic  -; N         44,715 (0.43;           316  rare.
 (Stenella frontalis).                                         31,610).
Bottlenose dolphin (Tursiops   W North           -; Y         3,751 (0.60;             23  Common year round.
 truncatus).                    Atlantic,                      2,353).
                                Southern
                                Migratory
                                Coastal.
Clymene dolphin (Stenella      W North Atlantic  -; N         Unknown (unk;         Undet  rare.
 clymene).                                                     unk; n/a).
Pantropical Spotted dolphin    W North Atlantic  -; N         3,333 (0.91;             17  rare.
 (Stenella attenuata).                                         1,733).
Risso's dolphin (Grampus       W North Atlantic  -; N         18,250 (0.46;           126  rare.
 griseus).                                                     12,619).
Common dolphin (Delphinus      W North Atlantic  -; N         70,184 (0.28;           557  Common year round.
 delphis).                                                     55,690).
Striped dolphin (Stenella      W North Atlantic  -; N         54,807 (0.3;            428  rare.
 coeruleoalba).                                                42,804).
Spinner Dolphin (Stenella      W North Atlantic  -; N         Unknown (unk;         Undet  rare.
 longirostris).                                                unk; n/a).
Harbor porpoise (Phocoena      Gulf of Maine/    -; N         79,833 (0.32;           706  Common year round.
 phocoena).                     Bay of Fundy.                  61,415).
Killer whale (Orcinus orca)..  W North Atlantic  -; N         Unknown (unk;         Undet  rare.
                                                               unk; n/a).
False killer whale (Pseudorca  W North Atlantic  -; Y         442 (1.06; 212).        2.1  rare.
 crassidens).
Long-finned pilot whale        W North Atlantic  -; Y         5,636 (0.63;             35  rare.
 (Globicephala melas).                                         3,464).
Short-finned pilot whale       W North Atlantic  -; Y         21,515 (0.37;           159  rare.
 (Globicephala macrorhynchus).                                 15,913).
Sperm whale (Physeter          North Atlantic..  E; Y         2,288 (0.28;            3.6  Year round in
 macrocephalus).                                               1,815).                      continental shelf
                                                                                            and slope waters,
                                                                                            occur seasonally to
                                                                                            forage.
Pygmy sperm whale \4\ (Kogia   W North Atlantic  -; N         3,785 (0.47;             26  rare.
 breviceps).                                                   2,598).
Dwarf sperm whale \4\ (Kogia   W North Atlantic  -; N         3,785 (0.47;             26  rare.
 sima).                                                        2,598).
Cuvier's beaked whale          W North Atlantic  -; N         6,532 (0.32;             50  rare.
 (Ziphius cavirostris).                                        5,021).
Blainville's beaked whale \5\  W North Atlantic  -; N         7,092 (0.54;             46  rare.
 (Mesoplodon densirostris).                                    4,632).
Gervais' beaked whale \5\      W North Atlantic  -; N         7,092 (0.54;             46  rare.
 (Mesoplodon europaeus).                                       4,632).
True's beaked whale \5\        W North Atlantic  -; N         7,092 (0.54;             46  rare.
 (Mesoplodon mirus).                                           4,632).
Sowerby's Beaked Whale \5\     W North Atlantic  -; N         7,092 (0.54;             46  rare.
 (Mesoplodon bidens).                                          4,632).
Melon-headed whale             W North Atlantic  -; N         Unknown (unk;         Undet  rare.
 (Peponocephala electra).                                      unk; n/a).
----------------------------------------------------------------------------------------------------------------
                                            Baleen whales (Mysticeti)
----------------------------------------------------------------------------------------------------------------
Minke whale (Balaenoptera      Canadian East     -; N         2,591 (0.81;             14  Year round in
 acutorostrata).                Coast.                         1,425).                      continental shelf
                                                                                            and slope waters,
                                                                                            occur seasonally to
                                                                                            forage.
Blue whale (Balaenoptera       W North Atlantic  E; Y         Unknown (unk;           0.9  Year round in
 musculus).                                                    440).                        continental shelf
                                                                                            and slope waters,
                                                                                            occur seasonally to
                                                                                            forage.
Fin whale (Balaenoptera        W North Atlantic  E; Y         1,618 (0.33;            2.5  Year round in
 physalus).                                                    1,234).                      continental shelf
                                                                                            and slope waters,
                                                                                            occur seasonally to
                                                                                            forage.
Humpback whale (Megaptera      Gulf of Maine...  -; Y         335 (0.42; 239).        3.7  Common year round.
 novaeangliae).
North Atlantic right whale     W North Atlantic  E; Y         458 (0; 455)....        1.4  Year round in
 (Eubalaena glacialis).                                                                     continental shelf
                                                                                            and slope waters,
                                                                                            occur seasonally to
                                                                                            forage.
Sei whale (Balaenoptera        Nova Scotia.....  E; Y         357 (0.52; 236).        0.5  Year round in
 borealis).                                                                                 continental shelf
                                                                                            and slope waters,
                                                                                            occur seasonally to
                                                                                            forage.
----------------------------------------------------------------------------------------------------------------
                                            Earless seals (Phocidae)
----------------------------------------------------------------------------------------------------------------
Gray seal \6\ (Halichoerus     W North Atlantic  -; N         27,131 (0.10;         1,554  Unlikely.
 grypus).                                                      25,908).
Harbor seal (Phoca vitulina).  W North Atlantic  -; N         75,834 (0.15;         2,006  Common year round.
                                                               66,884).
Hooded seal (Cystophora        W North Atlantic  -; N         Unknown (unk;         Undet  rare.
 cristata).                                                    unk).
Harp seal (Phoca               North Atlantic..  -; N         Unknown (unk;         Undet  rare.
 groenlandica).                                                unk).
----------------------------------------------------------------------------------------------------------------
\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\ 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 2017 Draft Atlantic SARs.
\3\ 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).
\4\ Abundance estimate includes both dwarf and pygmy sperm whales.
\5\ Abundance estimate includes all species of Mesoplodon in the Atlantic.
\6\ Abundance estimate applies to U.S. population only, actual abundance, including those occurring in Canada,
  is estimated at 505,000.

    All species that could potentially occur in the proposed survey 
areas are included in Table 2. However, the temporal and/or spatial 
occurrence for all but 11 of the species listed in Table 2 is such that 
take of these species is not expected to occur, and they are not 
discussed further beyond the explanation provided here. Take of these 
species is not anticipated either because they have very low densities 
in the project area, are known to occur

[[Page 26972]]

further offshore or further north than the project area, or are 
considered very unlikely to occur in the project area during the 
proposed survey due to the species' seasonal occurrence in the area. 
The 11 species/stocks evaluated for incidental take include: North 
Atlantic right whale; humpback whale; fin whale; minke whale; Atlantic 
white-sided dolphin; common dolphin; bottlenose dolphin; Atlantic 
spotted dolphin; long-finned pilot whale; short-finned pilot whale; and 
harbor porpoise.
    Five marine mammal species listed in Table 2 are listed under the 
ESA and are known to be present, at least seasonally, in waters of the 
mid-Atlantic (sperm whale, north Atlantic right whale, fin whale, blue 
whale, and sei whale). All of these species are highly migratory and do 
not spend extended periods of time in the localized survey area. The 
offshore waters of Virginia (including the survey area) are primarily 
used as a migration corridor for these species, particularly north 
Atlantic right whales, during seasonal movements north or south between 
feeding and breeding grounds (Knowlton et al., 2002; Firestone et al., 
2008). While fin and north Atlantic right whales have the potential to 
occur within the survey area, sperm, blue, and sei whales are more 
pelagic and/or northern species and their presence within the survey 
area is unlikely (Waring et al., 2007; 2010; 2012; 2013) and these 
species are therefore not considered further in this analysis. In 
addition, while stranding data exists for harbor and gray seals along 
the mid-Atlantic coast south of New Jersey, their preference for 
colder, northern waters during the survey period makes their presence 
in the survey area unlikely. Winter haulout sites for harbor seals have 
been identified within the Chesapeake Bay region. However, the seals 
are not present during the summer and fall months when the survey 
activities are planned (Waring et al., 2016). In addition, coastal 
Virginia represents the southern extent of the habitat range for gray 
seals, with few stranding records reported and sightings only occur 
during winter months as far south as New Jersey (Waring et al., 2016). 
Therefore pinniped species will not be discussed further in this 
analysis.
    Below is a description of the species that are both common in the 
survey area and that have the highest likelihood of occurring, at least 
seasonally, in the survey area and are thus have potential to be taken 
by the proposed activities.

North Atlantic Right Whale

    The North Atlantic right whale ranges from the calving grounds in 
the southeastern United States to feeding grounds in New England waters 
and into Canadian waters (Waring et al., 2016). Surveys have 
demonstrated the existence of seven areas where North Atlantic right 
whales congregate seasonally, including Georges Bank, Cape Cod, and 
Massachusetts Bay (Waring et al., 2016). In the late fall months (e.g. 
October), right whales generally disappear from the feeding grounds in 
the North Atlantic and move south to their breeding grounds. The 
proposed survey area is within the North Atlantic right whale migratory 
corridor. During the proposed survey (i.e., March through August) right 
whales may be migrating through the proposed survey area and the 
surrounding waters.
    The western North Atlantic population demonstrated overall growth 
of 2.8 percent per year between 1990 to 2010, despite a decline in 1993 
and no growth between 1997 and 2000 (Pace et al., 2017). However, since 
2010 the population has been in decline, with a 99.99 percent 
probability of a decline of just under 1 percent per year (Pace et al., 
2017). Between 1990 and 2015, calving rates varied substantially, with 
low calving rates coinciding with all three periods of decline or no 
growth (Pace et al., 2017). On average, North Atlantic right whale 
calving rates are estimated to be roughly half that of southern right 
whales (Eubalaena australis) (Pace et al. 2017), which are increasing 
in abundance (NMFS 2015).
    The current abundance estimate for this stock is 458 individuals 
(Hayes et al., 2018). Data indicates that the number of adult females 
fell from 200 in 2010 to 186 in 2015 while males fell from 283 to 272 
in the same timeframe (Pace et al., 2017). In addition, elevated North 
Atlantic right whale mortalities have occurred since June 7, 2017. A 
total of 18 confirmed dead stranded whales (12 in Canada; 6 in the 
United States), with an additional 5 live whale entanglements in 
Canada, have been documented to date. This event has been declared an 
Unusual Mortality Event (UME). More information is available online at: 
http://www.nmfs.noaa.gov/pr/health/mmume/2017northatlanticrightwhaleume.html.
    The lease area is part of a biologically important migratory area 
for North Atlantic right whales; this important migratory area is 
comprised of the waters of the continental shelf offshore the east 
coast of the United States and extends from Florida through 
Massachusetts. Given the limited spatial extent of the proposed survey 
and the large spatial extent of the migratory area, we do not expect 
North Atlantic right whale migration to be negatively impacted by the 
proposed survey. There is no designated critical habitat for any ESA-
listed marine mammals in the proposed survey area. NMFS' regulations at 
50 CFR 224.105 designated the nearshore waters of the Mid-Atlantic 
Bight as the Mid-Atlantic U.S. Seasonal Management Area (SMA) for right 
whales in 2008. Mandatory vessel speed restrictions (less than 10 kn) 
are in place in that SMA from November 1 through April 30 to reduce the 
threat of collisions between ships and right whales around their 
migratory route and calving grounds.

Humpback Whale

    Humpback whales are found worldwide in all oceans. The humpback 
whale population within the North Atlantic has been estimated to 
include approximately 11,570 individuals (Waring et al., 2016). 
Humpbacks occur off southern New England in all four seasons, with peak 
abundance in spring and summer. In winter, humpback whales from waters 
off New England, Canada, Greenland, Iceland, and Norway migrate to mate 
and calve primarily in the West Indies (including the Antilles, the 
Dominican Republic, the Virgin Islands and Puerto Rico), where spatial 
and genetic mixing among these groups occurs (Waring et al., 2015). 
While migrating, humpback whales utilize the mid-Atlantic as a 
migration pathway between calving/mating grounds to the south and 
feeding grounds in the north (Waring et al. 2007).
    Since January 2016, elevated humpback whale mortalities have 
occurred along the Atlantic coast from Maine through North Carolina. 
This event has been declared a UME. Partial or full necropsy 
examinations have been conducted on approximately half of the 68 known 
cases. A portion of the whales have shown evidence of pre-mortem vessel 
strike; however, this finding is not consistent across all of the 
whales examined so more research is needed. NOAA is consulting with 
researchers that are conducting studies on the humpback whale 
populations, and these efforts may provide information on changes in 
whale distribution and habitat use that could provide additional 
insight into how these vessel interactions occurred. Three previous 
UMEs involving humpback whales have occurred since 2000, in 2003, 2005, 
and 2006. More information is available at www.nmfs.noaa.gov/pr/health/mmume/2017humpbackatlanticume.html.

[[Page 26973]]

Fin Whale

    Fin whales are common in waters of the U.S. Atlantic Exclusive 
Economic Zone (EEZ), principally from Cape Hatteras northward (Waring 
et al., 2016). Fin whales are present north of 35-degree latitude in 
every season and are broadly distributed throughout the western North 
Atlantic for most of the year (Waring et al., 2016). Fin whales are 
found in small groups of up to 5 individuals (Brueggeman et al., 1987). 
The current abundance estimate for the western North Atlantic stock of 
fin whales is 1,618 individuals (Hayes et al., 2017).

Minke Whale

    Minke whales can be found in temperate, tropical, and high-latitude 
waters. The Canadian East Coast stock can be found in the area from the 
western half of the Davis Strait (45[deg] W) to the Gulf of Mexico 
(Waring et al., 2016). This species generally occupies waters less than 
100 m deep on the continental shelf. There appears to be a strong 
seasonal component to minke whale distribution in which spring to fall 
are times of relatively widespread and common occurrence, and when the 
whales are most abundant in New England waters, while during winter the 
species appears to be largely absent (Waring et al., 2016).

Atlantic White-Sided Dolphin

    White-sided dolphins are found in temperate and sub-polar waters of 
the North Atlantic, primarily in continental shelf waters to the 100-m 
depth contour from central West Greenland to North Carolina (Waring et 
al., 2016). There are three stock units: Gulf of Maine, Gulf of St. 
Lawrence, and Labrador Sea stocks (Palka et al., 1997). The Gulf of 
Maine population of white-sided dolphins is most common in continental 
shelf waters from Hudson Canyon (approximately 39[deg] N) to Georges 
Bank, and in the Gulf of Maine and lower Bay of Fundy. Sighting data 
indicate seasonal shifts in distribution (Northridge et al., 1997). 
During January to May, low numbers of white-sided dolphins are found 
from Georges Bank to Jeffreys Ledge (off New Hampshire), with even 
lower numbers south of Georges Bank, as documented by a few strandings 
collected on beaches of Virginia to South Carolina. From June through 
September, large numbers of white-sided dolphins are found from Georges 
Bank to the lower Bay of Fundy. From October to December, white-sided 
dolphins occur at intermediate densities from southern Georges Bank to 
southern Gulf of Maine (Payne and Heinemann 1990). Sightings south of 
Georges Bank, particularly around Hudson Canyon, occur year round but 
at low densities. The current abundance estimate for this stock is 
48,819 (Hayes et al., 2017). The main threat to this species is 
interactions with fisheries.

Common Dolphin

    The common dolphin is found worldwide in temperate to subtropical 
seas. In the North Atlantic, short-beaked common dolphins are commonly 
found over the continental shelf between the 100-m and 2000-m isobaths 
and over prominent underwater topography and east to the mid-Atlantic 
Ridge (Waring et al., 2016). Only the western North Atlantic stock may 
be present in the Lease Area. The current abundance estimate for this 
stock is 70,184 animals (Hayes et al., 2017). The main threat to this 
species is interactions with fisheries.

Bottlenose Dolphin

    Bottlenose dolphins occur in oceans and peripheral seas at both 
tropical and temperate latitudes. The population of bottlenose dolphins 
in the North Atlantic consists of a complex mosaic of stocks (Waring et 
al., 2016). There are two distinct morphotypes: Migratory coastal and 
offshore. The migratory coastal morphotype resides in waters typically 
less than 20 m (65.6 ft) deep, along the inner continental shelf, 
around islands, and is continuously distributed south of Long Island, 
NY into the Gulf of Mexico. This migratory coastal population is 
subdivided into seven stocks based largely upon spatial distribution 
(Waring et al., 2016). Of these seven coastal stocks, the Western North 
Atlantic migratory coastal stock is common in the coastal continental 
shelf water off the North Carolina/Virginia border Waring et al., 
2016). There are northern and southern Western North Atlantic migratory 
coastal stocks, and we would anticipate the southern stock to be 
present in the survey area. These animals move into or reside in bays, 
estuaries, lower reaches of rivers, and coastal waters within the 
approximately 25 m depth isobath north of Cape Hatteras (Reeves et al., 
2002; Waring et al., 2016). During winter, bottlenose dolphins are 
rarely observed north of the North Carolina/Virginia border (Waring et 
al., 2016).
    Generally, the offshore migratory morphotype is found exclusively 
seaward of 34 km (21 miles) and in waters deeper than 34 m (111.5 ft). 
The offshore population extends along the entire continental shelf 
break from Georges Bank to Florida during the spring and summer months, 
and has been observed in the Gulf of Maine during the late summer and 
fall. However, the range of the offshore morphotype south of Cape 
Hatteras has recently been found to overlap with that of the migratory 
coastal morphotype in water depths of 13 m (42.7 ft) (Waring et al., 
2016; Hayes et al., 2017). The main threat to this species is human 
interaction due to interactions with commercial fisheries (Waring et 
al., 2016). They have also been adversely affected by pollution, 
habitat alteration, boat collisions, human disturbance, and are subject 
to bioaccumulation of toxins.

Atlantic Spotted Dolphin

    There are two species of spotted dolphin in the Atlantic Ocean, the 
Atlantic spotted dolphin, and the pantropical spotted dolphin (Perrin 
1987). Where they co-occur, the two species can be difficult to 
differentiate. In addition, two forms of the Atlantic spotted dolphin 
exist with one that is large and heavily spotted and the other smaller 
in size with less spots (Waring et al., 2016). The larger form is 
associated with continental shelf habitat while the smaller form is 
more pelagic, preferring offshore waters and waters around oceanic 
islands (Perrin, 2009; 1994). The Atlantic spotted dolphin prefers 
tropical to warm temperate waters along the continental shelf 10 to 200 
m (33 to 650 ft) deep to slope waters greater than 500 m (1,640 ft).

Risso's Dolphin

    Risso's dolphin is typically an offshore dolphin that is uncommon 
to see inshore (Reeves et al., 2002). Risso's dolphin prefers temperate 
to tropical waters along the continental shelf edge and can range from 
Cape Hatteras to Georges Bank from spring through fall, and throughout 
the mid-Atlantic Bight out to oceanic waters during winter (Payne et 
al., 1984). Risso's dolphins are usually seen in groups of 12 to 40, 
but loose aggregations of 100 to 200 or more are seen occasionally 
(Reeves et al., 2002).

Long-Finned and Short-Finned Pilot Whales

    The two species of pilot whales in the western Atlantic are 
difficult to differentiate. Therefore, both species are presented 
together, since much of the data is generalized for these species. Both 
species are generally found along the edge of the continental shelf at 
depths of 100 to 1,000 m (330 to 3,300 ft) in areas of high reliefs or 
submerged banks. In the western North Atlantic, long-finned pilot 
whales are pelagic, occurring in especially high densities in

[[Page 26974]]

winter and spring over the continental slope, then moving inshore and 
onto the shelf in summer and fall following squid and mackerel 
populations (Reeves et al., 2002). Short-finned pilot whales prefer 
tropical, subtropical and warm temperate waters (Olsen, 2009). The 
short-finned pilot whale ranges from New Jersey south through Florida, 
the northern Gulf of Mexico, and the Caribbean (Warring et al., 2011). 
Populations for both of these species overlap between North Carolina 
and New Jersey (Waring et al., 2012; 2011)

Harbor Porpoise

    In the Lease Area, only the Gulf of Maine/Bay of Fundy stock may be 
present. This stock is found in U.S. and Canadian Atlantic waters and 
is concentrated in the northern Gulf of Maine and southern Bay of Fundy 
region, generally in waters less than 150 m deep (Waring et al., 2016). 
They are seen from the coastline to deep waters (>1,800 m; Westgate et 
al. 1998), although the majority of the population is found over the 
continental shelf (Waring et al., 2016). Average group size for this 
stock in the Bay of Fundy is approximately four individuals (Palka 
2007). The current abundance estimate for this stock is 79,883 (Hayes 
et al., 2017). The main threat to this 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).

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 
decibels (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):
    <bullet> Low-frequency cetaceans (mysticetes): Generalized hearing 
is estimated to occur between approximately 7 Hertz (Hz) and 35 
kilohertz (kHz);
    <bullet> Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): Generalized hearing is estimated to occur 
between approximately 150 Hz and 160 kHz;
    <bullet> 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.
    <bullet> Pinnipeds in water; Phocidae (true seals): Generalized 
hearing is estimated to occur between approximately 50 Hz to 86 kHz;
    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 (2016) for a review of available information. 
Eleven marine mammal species (all cetacean species) have the reasonable 
potential to co-occur with the proposed survey activities. Please refer 
to Table 2. Of the species that may be present, four are classified as 
low-frequency cetaceans (i.e., all mysticete species), six are 
classified as mid-frequency cetaceans (i.e., all delphinid species), 
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.

Background on Sound

    Sound is a physical phenomenon consisting of minute vibrations that 
travel through a medium, such as air or water, and is generally 
characterized by several variables. Frequency describes the sound's 
pitch and is measured in Hz or kHz, while sound level describes the 
sound's intensity and is measured in dB. Sound level increases or 
decreases exponentially with each dB of change. The logarithmic nature 
of the scale means that each 10-dB increase is a 10-fold increase in 
acoustic power (and a 20-dB increase is then a 100-fold increase in 
power). A 10-fold increase in acoustic power does not mean that the 
sound is perceived as being 10 times louder, however. Sound levels are 
compared to a reference sound pressure (micro Pascal) to identify the 
medium. For air and water, these reference pressures are ``re: 20 micro 
Pascals ([micro]Pa)'' and ``re: 1 [micro]Pa,'' respectively. Root mean 
square (rms) is the quadratic mean sound pressure over the duration of 
an impulse. Rms is calculated by squaring all of the sound amplitudes, 
averaging the squares, and then taking the square root of the average 
(Urick 1975). Rms 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. 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 rather than by peak 
pressures.
    When sound travels (propagates) from its source, its loudness 
decreases as the distance traveled by the sound increases. Thus, the 
loudness of a sound at its source is higher than the loudness of that 
same sound one km away. Acousticians often refer to the loudness of a 
sound at its source (typically referenced to one m from the source) as

[[Page 26975]]

the source level and the loudness of sound elsewhere as the received 
level (i.e., typically the receiver). For example, a humpback whale 3 
km from a device that has a source level of 230 dB may only be exposed 
to sound that is 160 dB loud, depending on how the sound travels 
through water (e.g., spherical spreading (6 dB reduction with doubling 
of distance) was used in this example). As a result, it is important to 
understand the difference between source levels and received levels 
when discussing the loudness of sound in the ocean or its impacts on 
the marine environment.
    As sound travels from a source, its propagation in water is 
influenced by various physical characteristics, including water 
temperature, depth, salinity, and surface and bottom properties that 
cause refraction, reflection, absorption, and scattering of sound 
waves. Oceans are not homogeneous and the contribution of each of these 
individual factors is extremely complex and interrelated. The physical 
characteristics that determine the sound's speed through the water will 
change with depth, season, geographic location, and with time of day 
(as a result, in actual active sonar operations, crews will measure 
oceanic conditions, such as sea water temperature and depth, to 
calibrate models that determine the path the sonar signal will take as 
it travels through the ocean and how strong the sound signal will be at 
a given range along a particular transmission path). As sound travels 
through the ocean, the intensity associated with the wavefront 
diminishes, or attenuates. This decrease in intensity is referred to as 
propagation loss, also commonly called transmission loss.

Acoustic Impacts

    Geophysical (HRG) surveys may temporarily impact marine mammals in 
the area due to elevated in-water sound levels. Marine mammals are 
continually exposed to many sources of sound. Naturally occurring 
sounds such as lightning, rain, sub-sea earthquakes, and biological 
sounds (e.g., snapping shrimp, whale songs) are widespread throughout 
the world's oceans. Marine mammals produce sounds in various contexts 
and use sound for various biological functions including, but not 
limited to: (1) Social interactions; (2) foraging; (3) orientation; and 
(4) predator detection. Interference with producing or receiving these 
sounds may result in adverse impacts. Audible distance, or received 
levels of sound depend on the nature of the sound source, ambient noise 
conditions, and the sensitivity of the receptor to the sound 
(Richardson et al., 1995). Type and significance of marine mammal 
reactions to sound are likely dependent on a variety of factors 
including, but not limited to, (1) the behavioral state of the animal 
(e.g., feeding, traveling, etc.); (2) frequency of the sound; (3) 
distance between the animal and the source; and (4) the level of the 
sound relative to ambient conditions (Southall et al., 2007).
    When considering the influence of various kinds of sound on the 
marine environment, it is necessary to understand that different kinds 
of marine life are sensitive to different frequencies of sound. Current 
data indicate that not all marine mammal species have equal hearing 
capabilities (Richardson et al., 1995; Wartzok and Ketten, 1999; Au and 
Hastings, 2008).
    Animals are less sensitive to sounds at the outer edges of their 
functional hearing range and are more sensitive to a range of 
frequencies within the middle of their functional hearing range. For 
mid-frequency cetaceans, functional hearing estimates occur between 
approximately 150 Hz and 160 kHz with best hearing estimated to occur 
between approximately 10 to less than 100 kHz (Finneran et al., 2005 
and 2009, Natchtigall et al., 2005 and 2008; Yuen et al., 2005; Popov 
et al., 2011; and Schlundt et al., 2011).

Hearing Impairment

    Marine mammals may experience temporary or permanent hearing 
impairment when exposed to loud sounds. Hearing impairment is 
classified by temporary threshold shift (TTS) and permanent threshold 
shift (PTS). PTS is considered auditory injury (Southall et al., 2007) 
and occurs in a specific frequency range and amount. Irreparable damage 
to the inner or outer cochlear hair cells may cause PTS; however, other 
mechanisms are also involved, such as exceeding the elastic limits of 
certain tissues and membranes in the middle and inner ears and 
resultant changes in the chemical composition of the inner ear fluids 
(Southall et al., 2007). There are no empirical data for onset of PTS 
in any marine mammal; therefore, PTS-onset must be estimated from TTS-
onset measurements and from the rate of TTS growth with increasing 
exposure levels above the level eliciting TTS-onset. PTS is presumed to 
be likely if the hearing threshold is reduced by >=40 dB (that is, 40 
dB of TTS).

Threshold Shift

    Marine mammals exposed to high-intensity sound, or to lower-
intensity sound for prolonged periods, can experience hearing threshold 
shift (TS), which is the loss of hearing sensitivity at certain 
frequency ranges (Finneran, 2015). TS can be permanent (PTS), in which 
case the loss of hearing sensitivity is not fully recoverable, or 
temporary (TTS), in which case the animal's hearing threshold would 
recover over time (Southall et al., 2007). Repeated sound exposure that 
leads to TTS could cause PTS. In severe cases of PTS, there can be 
total or partial deafness, while in most cases the animal has an 
impaired ability to hear sounds in specific frequency ranges (Kryter, 
1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several dB 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

[[Page 26976]]

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 (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and three species of pinnipeds (northern elephant 
seal, harbor seal, and California sea lion) 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). 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 (2016).
    Animals in the survey area during the HRG surveys are unlikely to 
incur TTS hearing impairment due to the characteristics of the sound 
sources, which include fairly low source levels and generally very 
short pulses and duration of the sound. Even for high-frequency 
cetacean species (e.g., harbor porpoises), which may have increased 
sensitivity to TTS (Lucke et al., 2009; Kastelein et al., 2012b), 
individuals would have to make a very close approach and also remain 
very close to vessels operating these sources in order to receive 
multiple exposures at relatively high levels, as would be necessary to 
cause TTS. Intermittent exposures--as would occur due to the brief, 
transient signals produced by these sources--require a higher 
cumulative sound exposure level (SEL) to induce TTS than would 
continuous exposures of the same duration (i.e., intermittent exposure 
results in lower levels of TTS) (Mooney et al., 2009a; Finneran et al., 
2010). Moreover, most marine mammals would more likely avoid a loud 
sound source rather than swim in such close proximity as to result in 
TTS. Kremser et al., (2005) noted that the probability of a cetacean 
swimming through the area of exposure when a sub-bottom profiler emits 
a pulse is small--because if the animal was in the area, it would have 
to pass the transducer at close range in order to be subjected to sound 
levels that could cause TTS and would likely exhibit avoidance behavior 
to the area near the transducer rather than swim through at such a 
close range. Further, the restricted beam shape of the sub-bottom 
profiler and other HRG survey equipment makes it unlikely that an 
animal would be exposed more than briefly during the passage of the 
vessel. Boebel et al., (2005) concluded similarly for single and 
multibeam echosounders and, more recently, Lurton (2016) conducted a 
modeling exercise and concluded similarly that likely potential for 
acoustic injury from these types of systems is negligible but that 
behavioral response cannot be ruled out. Animals may avoid the area 
around the survey vessels, thereby reducing exposure. Any disturbance 
to marine mammals is likely to be in the form of temporary avoidance or 
alteration of opportunistic foraging behavior near the survey location. 
For similar reasons, and with implementation of mitigation measures, 
animals in the survey area during the HRG surveys are unlikely to incur 
PTS hearing impairment; however, a small number of PTS takes are 
evaluated for authorization as discussed in more detail in the 
Estimated Take section.

Masking

    Masking is the obscuring of sounds of interest to an animal by 
other sounds, typically at similar frequencies. Marine mammals are 
highly dependent on sound, and their ability to recognize sound signals 
amid other sound is important in communication and detection of both 
predators and prey (Tyack 2000). Background ambient sound may interfere 
with or mask the ability of an animal to detect a sound signal even 
when that signal is above its absolute hearing threshold. Even in the 
absence of anthropogenic sound, the marine environment is often loud. 
Natural ambient sound includes contributions from wind, waves, 
precipitation, other animals, and (at frequencies above 30 kHz) thermal 
sound resulting from molecular agitation (Richardson et al., 1995).
    Background sound may also include anthropogenic sound, and masking 
of natural sounds can result when human activities produce high levels 
of background sound. Conversely, if the background level of underwater 
sound is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked. 
Ambient sound is highly variable on continental shelves (Myrberg 1978; 
Desharnais et al., 1999). This results in a high degree of variability 
in the range at which marine mammals can detect anthropogenic sounds.
    Although masking is a phenomenon which may occur naturally, the 
introduction of loud anthropogenic sounds into the marine environment 
at frequencies important to marine mammals increases the severity and 
frequency of occurrence of masking. For example, if a baleen whale is 
exposed to continuous low-frequency sound from an industrial source, 
this would reduce the size of the area around that whale within which 
it can hear the calls of another whale. The components of background 
noise that are similar in frequency to the signal in question primarily 
determine the degree of masking of that signal. In general, little is 
known about the degree to which marine mammals rely upon detection of 
sounds from conspecifics, predators, prey, or other natural sources. In 
the absence of specific information about the importance of detecting 
these natural sounds, it is not possible to predict the impact of 
masking on marine mammals (Richardson et al., 1995). In general, 
masking effects are expected to be less severe when sounds are 
transient than when they are continuous. Masking is typically of 
greater concern for those marine mammals that utilize low-frequency 
communications, such as baleen whales, because of how far low-frequency 
sounds propagate.
    Marine mammal communications would not likely be masked appreciably 
by the proposed HRG equipment signals given the directionality of the 
signal and the brief period when an individual mammal is likely to be 
within its beam.

Non-Auditory Physical Effects (Stress)

    Classic stress responses begin when an animal's central nervous 
system

[[Page 26977]]

perceives a potential threat to its homeostasis. That perception 
triggers stress responses regardless of whether a stimulus actually 
threatens the animal; the mere perception of a threat is sufficient to 
trigger a stress response (Moberg 2000; Seyle 1950). Once an animal's 
central nervous system perceives a threat, it mounts a biological 
response or defense that consists of a combination of the four general 
biological defense responses: Behavioral responses, autonomic nervous 
system responses, neuroendocrine responses, or immune responses.
    In the case of many stressors, an animal's first and sometimes most 
economical (in terms of biotic costs) response is behavioral avoidance 
of the potential stressor or avoidance of continued exposure to a 
stressor. An animal's second line of defense to stressors involves the 
sympathetic part of the autonomic nervous system and the classical 
``fight or flight'' response which includes the cardiovascular system, 
the gastrointestinal system, the exocrine glands, and the adrenal 
medulla to produce changes in heart rate, blood pressure, and 
gastrointestinal activity that humans commonly associate with 
``stress.'' These responses have a relatively short duration and may or 
may not have significant long-term effect on an animal's welfare.
    An animal's third line of defense to stressors involves its 
neuroendocrine systems; the system that has received the most study has 
been the hypothalamus-pituitary-adrenal system (also known as the HPA 
axis in mammals). Unlike stress responses associated with the autonomic 
nervous system, virtually all neuro-endocrine 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 (Moberg 1987; Rivier 1995), altered 
metabolism (Elasser et al., 2000), reduced immune competence (Blecha 
2000), and behavioral disturbance. Increases in the circulation of 
glucocorticosteroids (cortisol, corticosterone, and aldosterone in 
marine mammals; see Romano et al., 2004) have been equated with stress 
for many years.
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and distress is the biotic 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 a 
risk to the animal's welfare. 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 biotic function, 
which impairs those functions that experience the diversion. For 
example, when mounting a stress response diverts energy away from 
growth in young animals, those animals may experience stunted growth. 
When mounting a stress response diverts energy from a fetus, an 
animal's reproductive success and its fitness will suffer. In these 
cases, the animals will have entered a pre-pathological or pathological 
state which is called ``distress'' (Seyle 1950) or ``allostatic 
loading'' (McEwen and Wingfield 2003). This pathological state will 
last until the animal replenishes its biotic reserves sufficient to 
restore normal function. Note that these examples involved a long-term 
(days or weeks) stress response exposure to stimuli.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses have also been documented 
fairly well through controlled experiments; because this physiology 
exists in every vertebrate that has been studied, it is not surprising 
that stress responses and their costs have been documented in both 
laboratory and free-living animals (for examples see, Holberton et al., 
1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004; 
Lankford et al., 2005; Reneerkens et al., 2002; Thompson and Hamer, 
2000). Information has also been collected on the physiological 
responses of marine mammals to exposure to anthropogenic sounds (Fair 
and Becker 2000; Romano et al., 2002). 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.
    Studies of other marine animals and terrestrial animals would also 
lead us to expect some marine mammals to experience physiological 
stress responses and, perhaps, physiological responses that would be 
classified as ``distress'' upon exposure to high frequency, mid-
frequency and low-frequency sounds. For example, Jansen (1998) reported 
on the relationship between acoustic exposures and physiological 
responses that are indicative of stress responses in humans (for 
example, elevated respiration and increased heart rates). Jones (1998) 
reported on reductions in human performance when faced with acute, 
repetitive exposures to acoustic disturbance. Trimper et al., (1998) 
reported on the physiological stress responses of osprey to low-level 
aircraft noise while Krausman et al., (2004) reported on the auditory 
and physiology stress responses of endangered Sonoran pronghorn to 
military overflights. Smith et al., (2004a, 2004b), for example, 
identified noise-induced physiological transient stress responses in 
hearing-specialist fish (i.e., goldfish) that accompanied short- and 
long-term hearing losses. Welch and Welch (1970) reported physiological 
and behavioral stress responses that accompanied damage to the inner 
ears of fish and several mammals.
    Hearing is one of the primary senses marine mammals use to gather 
information about their environment and to communicate with 
conspecifics. Although empirical information on the relationship 
between sensory impairment (TTS, PTS, and acoustic masking) on marine 
mammals remains limited, it seems reasonable to assume that reducing an 
animal's ability to gather information about its environment and to 
communicate with other members of its species would be stressful for 
animals that use hearing as their primary sensory mechanism. Therefore, 
we assume that acoustic exposures sufficient to trigger onset PTS or 
TTS would be accompanied by physiological stress responses because 
terrestrial animals exhibit those responses under similar conditions 
(NRC 2003). More importantly, marine mammals might experience stress 
responses at received levels lower than those necessary to trigger 
onset TTS. Based on empirical studies of the time required to recover 
from stress responses (Moberg 2000), we also assume that stress 
responses are likely to persist beyond the time interval required for 
animals to recover from TTS and might result in pathological and pre-
pathological states that would be as significant as behavioral 
responses to TTS.
    In general, there are few data on the potential for strong, 
anthropogenic underwater sounds to cause non-auditory physical effects 
in marine mammals. The available data do not allow identification of a 
specific exposure level above which non-auditory effects can be 
expected (Southall et al., 2007). There is no definitive evidence that 
any of these effects occur even for marine mammals in close proximity 
to an anthropogenic sound source. In addition, marine mammals that show 
behavioral avoidance of survey vessels and related sound sources are 
unlikely to incur non-auditory impairment or other physical

[[Page 26978]]

effects. NMFS does not expect that the generally short-term, 
intermittent, and transitory HRG activities would create conditions of 
long-term, continuous noise and chronic acoustic exposure leading to 
long-term physiological stress responses in marine mammals.

Behavioral Disturbance

    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 shown pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud, pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, et al., 
one the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart 2007; NRC 2005). 
However, there are broad categories of potential response, which we 
describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark 2000; Costa et al., 2003; Ng and Leung 2003; Nowacek et al., 
2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007b). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise

[[Page 26979]]

from seismic surveys (Malme et al., 1984). Avoidance may be short-term, 
with animals returning to the area once the noise has ceased (e.g., 
Bowles et al., 1994; Goold 1996; Stone et al., 2000; Morton and 
Symonds, 2002; Gailey et al., 2007). Longer-term displacement is 
possible, however, which may lead to changes in abundance or 
distribution patterns of the affected species in the affected region if 
habituation to the presence of the sound does not occur (e.g., 
Blackwell et al., 2004; Bejder et al., 2006; Teilmann et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996). The result of a flight response could range from 
brief, temporary exertion and displacement from the area where the 
signal provokes flight to, in extreme cases, marine mammal strandings 
(Evans and England, 2001). However, it should be noted that response to 
a perceived predator does not necessarily invoke flight (Ford and 
Reeves, 2008) and whether individuals are solitary or in groups may 
influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al., (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Marine mammals are likely to avoid the HRG survey activity, 
especially the naturally shy harbor porpoise, while some dolphin 
species might be attracted to them out of curiosity. However, because 
the sub-bottom profilers and other HRG survey equipment operate from a 
moving vessel, and the maximum radius to the Level B harassment 
threshold is relatively small, the area and time that this equipment 
would be affecting a given location is very small. Further, once an 
area has been surveyed, it is not likely that it will be surveyed 
again, thereby reducing the likelihood of repeated HRG-related impacts 
within the survey area.
    We have also considered the potential for severe behavioral 
responses such as stranding and associated indirect injury or mortality 
from Dominion's use of HRG survey equipment, on the basis of a 2008 
mass stranding of approximately 100 melon-headed whales in a Madagascar 
lagoon system. An investigation of the event indicated that use of a 
high-frequency mapping system (12-kHz multibeam echosounder) was the 
most plausible and likely initial behavioral trigger of the event, 
while providing the caveat that there is no unequivocal and easily 
identifiable single cause (Southall et al., 2013). The investigatory 
panel's conclusion was based on (1) very close temporal and spatial 
association and directed movement of the survey with the stranding 
event; (2) the unusual nature of such an event coupled with previously 
documented apparent behavioral sensitivity of the species to other 
sound types (Southall et al., 2006; Brownell et al., 2009); and (3) the 
fact that all other possible factors considered were determined to be 
unlikely causes. Specifically, regarding survey patterns prior to the 
event and in relation to bathymetry, the vessel transited in a north-
south direction on the shelf break parallel to the shore, ensonifying 
large areas of deep-water habitat prior to operating intermittently in 
a concentrated area offshore from the stranding site; this may have 
trapped the animals between the sound source and the shore, thus 
driving them towards the lagoon system. The investigatory panel 
systematically excluded or deemed highly unlikely nearly all potential 
reasons for these animals leaving their typical pelagic habitat for an 
area extremely atypical for the species (i.e., a shallow lagoon 
system). Notably, this was the first time that such a system has been 
associated with a stranding event. The panel also noted several site- 
and situation-specific secondary factors that may have contributed to 
the avoidance responses that led to the eventual entrapment and 
mortality of the whales. Specifically, shoreward-directed surface 
currents and elevated chlorophyll levels in the area preceding the 
event may have played a role (Southall et al., 2013). The report also 
notes that prior use of a similar system in the general area may have 
sensitized the animals and also concluded that, for odontocete 
cetaceans that hear well in higher frequency ranges where ambient noise 
is typically quite low, high-power active sonars operating in this 
range may be more easily audible and have potential effects over larger 
areas than low frequency systems that have more typically been 
considered in terms of anthropogenic noise impacts. It is, however, 
important to note that the relatively lower output frequency, higher 
output power, and complex nature of the system implicated in this 
event, in context of the other factors noted here, likely produced a 
fairly unusual set of circumstances that indicate that such events 
would likely remain rare and are not necessarily relevant to use of 
lower-power, higher-frequency systems more commonly used for HRG survey 
applications. The risk of similar events recurring may be very low, 
given the extensive use of active acoustic systems used for scientific 
and navigational purposes worldwide on a daily basis and the lack of 
direct evidence of such responses previously reported.

Tolerance

    Numerous studies have shown that underwater sounds from industrial 
activities are often readily detectable by marine mammals in the water 
at distances of many km. However, other studies have shown that marine

[[Page 26980]]

mammals at distances more than a few km away often show no apparent 
response to industrial activities of various types (Miller et al., 
2005). This is often true even in cases when the sounds must be readily 
audible to the animals based on measured received levels and the 
hearing sensitivity of that mammal group. Although various baleen 
whales, toothed whales, and (less frequently) pinnipeds have been shown 
to react behaviorally to underwater sound from sources such as airgun 
pulses or vessels under some conditions, at other times, mammals of all 
three types have shown no overt reactions (e.g., Malme et al., 1986; 
Richardson et al., 1995; Madsen and Mohl 2000; Croll et al., 2001; 
Jacobs and Terhune 2002; Madsen et al., 2002; Miller et al., 2005).

Vessel Strike

    Ship strikes of marine mammals can cause major wounds, which may 
lead to the death of the animal. An animal at the surface could be 
struck directly by a vessel, a surfacing animal could hit the bottom of 
a vessel, or a vessel's propeller could injure an animal just below the 
surface. The severity of injuries typically depends on the size and 
speed of the vessel (Knowlton and Kraus 2001; Laist et al., 2001; 
Vanderlaan and Taggart 2007).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some baleen whales, such as the North Atlantic right whale, seem 
generally unresponsive to vessel sound, making them more susceptible to 
vessel collisions (Nowacek et al., 2004). These species are primarily 
large, slow moving whales. Smaller marine mammals (e.g., bottlenose 
dolphin) move quickly through the water column and are often seen 
riding the bow wave of large ships. Marine mammal responses to vessels 
may include avoidance and changes in dive pattern (NRC 2003).
    An examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike results in death (Knowlton and Kraus 2001; 
Laist et al., 2001; Jensen and Silber 2003; Vanderlaan and Taggart 
2007). In assessing records with known vessel speeds, Laist et al., 
(2001) found a direct relationship between the occurrence of a whale 
strike and the speed of the vessel involved in the collision. The 
authors concluded that most deaths occurred when a vessel was traveling 
in excess of 24.1 km/h (14.9 mph; 13 kn). Given the slow vessel speeds 
and predictable course necessary for data acquisition, ship strike is 
unlikely to occur during the geophysical surveys. Marine mammals would 
be able to easily avoid the survey vessel due to the slow vessel speed. 
Further, Dominion would implement measures (e.g., protected species 
monitoring, vessel speed restrictions and separation distances; see 
Proposed Mitigation Measures) set forth in the BOEM lease to reduce the 
risk of a vessel strike to marine mammal species in the survey area.

Marine Mammal Habitat

    There are no feeding areas, rookeries or mating grounds known to be 
biologically important to marine mammals within the proposed project 
area. We are not aware of any available literature on impacts to marine 
mammal prey from HRG survey equipment. However, as the HRG survey 
equipment introduces noise to the marine environment, there is the 
potential for it to result in avoidance of the area around the HRG 
survey activities on the part of marine mammal prey. Any avoidance of 
the area on the part of marine mammal prey would be expected to be 
short term and temporary. Because of the temporary nature of the 
disturbance, the availability of similar habitat and resources (e.g., 
prey species) in the surrounding area, and the lack of important or 
unique marine mammal habitat, 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. Impacts on marine mammal habitat from the proposed 
activities will be temporary, insignificant, and discountable.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, 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 be by Level B harassment only, as use of the 
HRG equipment has the potential to result in disruption of behavioral 
patterns for individual marine mammals. NMFS has determined take by 
Level A harassment is not an expected outcome of the proposed activity 
as discussed in greater detail below. As described previously, no 
mortality or serious injury is anticipated or proposed to be authorized 
for this activity. Below we describe how the take is estimated for this 
project.
    Described in the most basic way, 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. Below, we describe these 
components in more detail and present the proposed take estimate.

Acoustic Thresholds

    NMFS uses 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 
sound source (e.g., frequency, predictability, duty cycle); the 
environment (e.g., bathymetry); and the receiving animals (hearing, 
motivation, experience, demography, behavioral context); therefore can 
be difficult to predict (Southall et al., 2007, Ellison et al., 2011). 
NMFS uses a generalized acoustic threshold based on received level to 
estimate the onset of Level B (behavioral) harassment. NMFS predicts 
that marine mammals may be behaviorally harassed when exposed to 
underwater anthropogenic noise above received levels 160 dB re 1 [mu]Pa 
(rms) for non-explosive impulsive (e.g., seismic HRG equipment) or 
intermittent (e.g., scientific sonar) sources. Dominion's proposed 
activity includes the use of impulsive sources. Therefore, the 160 dB 
re 1 [mu]Pa (rms) criteria is applicable for analysis of Level B 
harassment.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on

[[Page 26981]]

Marine Mammal Hearing (NMFS 2016) 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 
Technical Guidance identifies the received levels, or thresholds, above 
which individual marine mammals are predicted to experience changes in 
their hearing sensitivity for all underwater anthropogenic sound 
sources, reflects the best available science, and better predicts the 
potential for auditory injury than does NMFS' historical criteria.
    These thresholds were developed by compiling and synthesizing the 
best available science and soliciting input multiple times from both 
the public and peer reviewers to inform the final product, and are 
provided in Table 3 below. The references, analysis, and methodology 
used in the development of the thresholds are described in NMFS 2016 
Technical Guidance, which may be accessed at: www.nmfs.noaa.gov/pr/acoustics/guidelines.htm. As described above, Dominion's proposed 
activity includes the use of intermittent and impulsive sources

            Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift in Marine Mammals
----------------------------------------------------------------------------------------------------------------
                                                                    PTS onset thresholds
              Hearing group               ----------------------------------------------------------------------
                                                    Impulsive *                       Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans.............  Lpk,flat: 219 dB; LE,LF,24h:  LE,LF,24h: 199 dB.
                                            183 dB.
Mid-Frequency (MF) Cetaceans.............  Lpk,flat: 230 dB; LE,MF,24h:  LE,MF,24h: 198 dB.
                                            185 dB.
High-Frequency (HF) Cetaceans............  Lpk,flat: 202 dB; LE,HF,24h:  LE,HF,24h: 173 dB.
                                            155 dB.
Phocid Pinnipeds (PW); (Underwater)......  Lpk,flat: 218 dB; LE,PW,24h:  LE,PW,24h: 201 dB.
                                            185 dB.
Otariid Pinnipeds (OW); (Underwater).....  Lpk,flat: 232 dB; LE,OW,24h:  LE,OW,24h: 219 dB.
                                            203 dB.
----------------------------------------------------------------------------------------------------------------
Note: * 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]Pa2s. In this Table, thresholds are abbreviated to reflect American National
  Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
  frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
  being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
  designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
  that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
  exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
  is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into estimating the area ensonified above the 
acoustic thresholds.
    The proposed survey would entail the use of HRG survey equipment. 
The distance to the isopleth corresponding to the threshold for Level B 
harassment was calculated for all HRG survey equipment with the 
potential to result in harassment of marine mammals (see Table 1). Of 
the HRG survey equipment planned for use that has the potential to 
result in harassment of marine mammals, acoustic modeling indicated the 
Innomar Medium 100 sub-bottom profiler would be expected to produce 
sound that would propagate the furthest in the water (Table 4); 
therefore, for the purposes of the take calculation, it was assumed 
this equipment would be active during the entirety of the survey. Thus 
the distance to the isopleth corresponding to the threshold for Level B 
harassment for the Innomar Medium 100 sub-bottom profiler (100 m; Table 
4) was used as the basis of the Level B take calculation for all marine 
mammals.

  Table 4--Predicted Radial Distances (m) From HRG Sources to Isopleths
              Corresponding to Level B Harassment Threshold
------------------------------------------------------------------------
                                                     Modeled distance to
          HRG system           HRG survey equipment   threshold (160 dB
                                                         re 1 [mu]Pa)
------------------------------------------------------------------------
Pinger/Chirper...............  GeoPulse sub-bottom                  <5 m
                                profiler.
Sparker......................  Geo-Source 800                      <20 m
                                sparker.
Medium penetration sub-bottom  Innomar Medium 100                *<100 m
 profiler.                      sub-bottom profiler.
------------------------------------------------------------------------
* We note here that the Innomar Medium 100 sub-bottom profiler operating
  frequencies (85-115 kHz) are beyond the best hearing capabilities of
  LF cetaceans (7-35 kHz), but as this sound source provides the largest
  Level B isopleth, this information was used to calculate the zone of
  influence and estimate take for all species.

    Predicted distances to Level A harassment isopleths, which vary 
based on marine mammal functional hearing groups (Table 5), were also 
calculated by Dominion. The updated acoustic thresholds for impulsive 
sounds (such as HRG survey equipment) contained in the Technical 
Guidance (NMFS, 2016) were presented as dual metric acoustic thresholds 
using both SEL<INF>cum</INF> and peak sound pressure level (SPL) 
metrics. As dual metrics, NMFS considers onset of PTS (Level A 
harassment) to have occurred when either one of the two metrics is 
exceeded (i.e., metric resulting in the largest isopleth). The 
SEL<INF>cum</INF> metric considers both level and duration of exposure, 
as well as auditory weighting functions by marine mammal hearing group. 
In recognition of the fact that calculating Level A harassment 
ensonified areas could be more technically challenging to predict due 
to the duration component and the use of weighting functions in the new 
SEL<INF>cum</INF> thresholds, NMFS developed an optional User 
Spreadsheet that includes tools to help predict a simple isopleth that 
can be used in conjunction with marine mammal density or occurrence

[[Page 26982]]

to facilitate the estimation of take numbers. Dominion used the NMFS 
optional User Spreadsheet to calculate distances to Level A harassment 
isopleths (see Appendix A of the IHA application). Modeled distances to 
isopleths corresponding to Level A harassment thresholds for the 
proposed HRG equipment and marine mammal hearing groups are shown in 
Table 5.

        Table 5--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds
----------------------------------------------------------------------------------------------------------------
    Functional hearing group (Level A
         harassment thresholds)                      PTS onset                      Lateral distance (m)
----------------------------------------------------------------------------------------------------------------
                                          GeoPulse Sub-Bottom Profiler
----------------------------------------------------------------------------------------------------------------
Low frequency cetaceans.................  219 dBpeak/....................  --
                                          183 dB SELcum..................  <1
Mid frequency cetaceans.................  230 dBpeak/....................  --
                                          185 dB SELcum..................  --
High frequency cetaceans................  202 dBpeak/....................  <1
                                          155 dB SELcum..................  16
Phocid Pinnipeds (Underwater)...........  218 dBpeak/....................  --
                                          185 dB SELcum..................  <1
----------------------------------------------------------------------------------------------------------------
                                             Geo-Source 800 Sparker
----------------------------------------------------------------------------------------------------------------
Low frequency cetaceans.................  219 dBpeak/....................  --
                                          183 dB SELcum..................  5
Mid frequency cetaceans.................  230 dBpeak/....................  --
                                          185 dB SELcum..................  <1
High frequency cetaceans................  202 dBpeak/....................  <1
                                          155 dB SELcum..................  24
Phocid Pinnipeds (Underwater)...........  218 dBpeak/....................  --
                                          185 dB SELcum..................  3
----------------------------------------------------------------------------------------------------------------
                                     Innomar Medium 100 Sub-Bottom Profiler
----------------------------------------------------------------------------------------------------------------
Low frequency cetaceans.................  219 dBpeak/....................  <1
                                          183 dB SELcum..................  N/A
Mid frequency cetaceans.................  230 dBpeak/....................  <1
                                          185 dB SELcum..................  --
High frequency cetaceans................  202 dBpeak/....................  <5
                                          155 dB SELcum..................  <50
Phocid Pinnipeds (Underwater)...........  218 dBpeak/....................  <1
                                          185 dB SELcum..................  N/A
----------------------------------------------------------------------------------------------------------------
Note: Peak SPL is unweighted (flat weighted), whereas the cumulative SEL criterion is M-weighted for the given
  marine mammal hearing group.
-- indicates not expected to be measureable to regulatory threshold at any appreciable distance.
N/A indicates not applicable as the HRG sound source is outside the effective marine mammal hearing range.

    In this case, due to the very small estimated distances to Level A 
harassment thresholds for all marine mammal functional hearing groups, 
based on both SEL<INF>cum</INF> and peak SPL (Table 5), and in 
consideration of the proposed mitigation measures, including marine 
mammal exclusion zones to avoid Level A harassment (see the Proposed 
Mitigation section for more detail) NMFS has determined that the 
likelihood of Level A take of marine mammals occurring as a result of 
the proposed survey is so low as to be discountable. However, to be 
conservative, Dominion has requested small amounts of Level A 
incidental take for bottlenose, common, and Atlantic white-sided 
dophins to specifically allow survey activities to continue, 
understanding the proclivity of these species to approach vessels to 
bow and/or wake ride and closely investigate active survey gear. 
Calculated distances presented in Table 5 indicates Level A PTS onset 
occurring at distances less than one m of the sound source (if at all) 
for mid-frequency cetaceans such as delphinids, and the applicant has 
calculated take based on a 5 m zone as an even more conservative 
measure for Level A take. However, due to the small Level A isopleth 
and the fact that animals are not likely to remain within this small 
zone for long enough to incur PTS, NMFS is not proposing to authorize 
Level A take for these species/stocks.
    We note that because of some of the assumptions included in the 
methods used, isopleths produced may be overestimates to some degree. 
The acoustic sources proposed for use in Dominion's survey do not 
radiate sound equally in all directions but were designed instead to 
focus acoustic energy directly toward the sea floor. Therefore, the 
acoustic energy produced by these sources is not received equally in 
all directions around the source but is instead concentrated along some 
narrower plane depending on the beamwidth of the source. For example, 
in the case of the Innomar Medium 100 sub-bottom profiler, the 
beamwidth is only one degree. However, the calculated distances to 
isopleths do not account for this directionality of the sound source 
and are therefore conservative. For mobile sources, such as the 
proposed survey, the User Spreadsheet predicts the closest distance at 
which a stationary animal would not incur PTS if the sound source 
traveled by the animal in a straight line at a constant speed. In 
addition to the conservative estimation of calculated distances to 
isopleths associated with the Innomar Medium 100 sub-bottom profiler, 
calculated takes may be conservative due to the fact that this sound 
source operates at frequencies beyond the best hearing capabilities of

[[Page 26983]]

LF cetaceans, but calculated takes for all species were based on the 
isopleths associated with this sound source. As discussed above, the 
Innomar Medium 100 sub-bottom profiler operates at frequencies between 
85 and 115 kHz and the best hearing range of LF cetaceans is between 7 
and 35 kHz. Therefore, we would not expect that take of LF cetaceans 
would likely occur due to the use of this equipment because it operates 
beyond their hearing capabilities, but takes were estimated based on 
these isopleths due to the fact that the largest distances were 
associated with this equipment.

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    The best available scientific information was considered in 
conducting marine mammal exposure estimates (the basis for estimating 
take). For cetacean species, densities calculated by Roberts et al. 
(2016) were used. The density data presented by Roberts et al. (2016) 
incorporates aerial and shipboard line-transect survey data from NMFS 
and from other organizations collected over the period 1992-2014. 
Roberts et al. (2016) modeled density from 8 physiographic and 16 
dynamic oceanographic and biological covariates, and controlled for the 
influence of sea state, group size, availability bias, and perception 
bias on the probability of making a sighting. In general, NMFS 
considers the models produced by Roberts et al. (2016) to be the best 
available source of data regarding cetacean density in the Atlantic 
Ocean. More information, including the model results and supplementary 
information for each model, is available online at: 
seamap.env.duke.edu/models/Duke-EC-GOM-2015/.
    For the purposes of the take calculations, density data from 
Roberts et al. (2016) were mapped within the boundary of the survey 
area for each survey segment (i.e., the Lease Area survey segment and 
the cable route area survey segment; See Figure 1 in the IHA 
application) using a geographic information system. Monthly density 
data for all cetacean species potentially taken by the proposed survey 
was available via Roberts et al. (2016). Monthly mean density within 
the survey area, as provided in Roberts et al. (2016), were averaged by 
season (i.e., Summer (June, July, August), and Fall (September, 
October, November)) to provide seasonal density estimates. The highest 
average seasonal density as reported by Roberts et al. (2016), for each 
species, was used based on the planned survey dates of August through 
October.

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 
are calculated, as described above. Those distances are then used to 
calculate the area(s) around the HRG survey equipment predicted to be 
ensonified to sound levels that exceed harassment thresholds. The area 
estimated to be ensonified to relevant thresholds in a single day of 
the survey is then calculated, based on areas predicted to be 
ensonified around the HRG survey equipment and estimated trackline 
distance traveled per day by the survey vessel. The estimated daily 
vessel track line distance was determined using the estimated average 
speed of the vessel (4 kn) multiplied by 24 (to account for the 24 hour 
operational period of the survey). Using the maximum distance to the 
regulatory threshold criteria (Tables 4 and 5) and estimated daily 
track line distance of approximately 177.8 km (110.5 mi), it was 
estimated that an area of 35.59 km\2\ (13.74 mi\2\) per day would be 
ensonified to the largest Level B harassment threshold, and 1.78 km\2\ 
(0.69 mi\2\) per day would be ensonifed to the Level A harassment 
threshold (largest threshold of 155 dB SEL<INF>cum</INF> for HF 
cetaceans was used) (Table 6).

  Table 6--Estimated Track Line Distance per Day (km) and Area (km\2\)
   Estimated To Be Ensonified to Level B Harassment Threshold per Day
------------------------------------------------------------------------
                                 Estimated area        Estimated area
                               ensonified to Level   ensonified to Level
    Estimated track line          A harassment          B harassment
    distance per day (km)       threshold per day     threshold per day
                                     (km\2\)               (km\2\)
------------------------------------------------------------------------
177.8.......................                 1.78                 35.59
------------------------------------------------------------------------

    The number of marine mammals expected to be incidentally taken per 
day is then calculated by estimating the number of each species 
predicted to occur within the daily ensonified area, using estimated 
marine mammal densities as described above. In this case, estimated 
marine mammal density values varied between the turbine positions, 
inter-array cable route corridor survey areas, and export cable route 
corridors; therefore, the estimated number of each species taken per 
survey day was calculated separately for the these survey areas. 
Estimated numbers of each species taken per day are then multiplied by 
the number of survey days to generate an estimate of the total number 
of each species expected to be taken over the duration of the survey. 
In this case, as the estimated number of each species taken per day 
varied depending on survey area (turbine positions, inter-array cable 
route, and export cable route corridor), the number of each species 
taken per day in each respective survey area was multiplied by the 
number of survey days anticipated in each survey area (i.e., 15 survey 
days each in the turbine position location and inter-array cable route, 
and 60 survey days in the export cable route corridor portion of the 
survey) to get a total number of takes per species in each respective 
survey area.
    As described above, due to the very small estimated distances to 
Level A harassment thresholds (based on both SEL<INF>cum</INF> and peak 
SPL; Table 5), and in consideration of the proposed mitigation 
measures, the likelihood of the proposed survey resulting in take in 
the form of Level A harassment is considered so unlikely as to be 
discountable. Proposed take numbers are shown in Table 7. As described 
above, the zone of influence (ZOI) were calculated based on the sound 
source with the largest isopleths to the regulatory thresholds (the 
Innomar

[[Page 26984]]

Medium 100 sub-bottom profiler) without consideration of the fact that 
this equipment operates beyond the best hearing capability of LF 
cetaceans, so calculated takes of these species are likely to be 
overestimates due to the fact that we would not necessarily expect LF 
cetaceans to be harassed by sound produced by this equipment.

              Table 7--Numbers of Potential Incidental Take of Marine Mammals Calculated and Proposed for Level B Harassment Authorization
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Turbine positions            Export cable route        Inter-array cable route             Totals
                                        ----------------------------------------------------------------------------------------------------------------
                Species                   Max. seasonal                Max. seasonal                Max. seasonal
                                         density \a\ (#/  Calculated  density \a\ (#/  Calculated  density \a\ (#/  Calculated    Adjusted       % of
                                          1,000 km\2\)      takes      1,000 km\2\)      takes      1,000 km\2\)      takes         take      population
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale.............            0.00            0            0.00         0.00            0.00         0.00        \b\ 0         0.00
Humpback whale.........................            0.02         0.10            0.02         0.39            0.02         0.10            1         0.30
Fin whale..............................            0.11         0.57            0.11         2.28            0.11         0.57        \b\ 0         0.00
Minke whale............................            0.03         0.14            0.03         0.58            0.03         0.14       \c\ 10         0.39
Bottlenose dolphin--N Coastal Migratory           13.99        74.69           13.99       298.77           13.99        74.69    \d e\ 350         9.33
Bottlenose dolphin--Offshore...........           13.99        74.69           13.99       298.77           13.99        74.69    \d e\ 350         9.33
Atlantic spotted dolphin...............            0.90         4.80            1.23        26.29            0.90         4.80      \c\ 300         0.67
Common dolphin.........................            2.50        13.35            2.50        53.40            2.50        13.35      \d\ 400         0.57
Atlantic white-sided dolphin...........            0.39         2.08            0.39         8.30            0.39         2.08      \c\ 200         0.41
Risso's dolphin........................            0.01         0.03            0.00         0.02            0.01         0.03            0         0.00
Short-finned/long-finned pilot whale...            0.06         0.31            0.02         0.53            0.06         0.31       \e\ 15         0.27
Harbor porpoise........................            0.27         1.45            0.23         4.91            0.27         1.45            8         0.01
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Density values from Duke University (Roberts et al., 2016).
\b\ Proposed mitigation (exclusion zone) will prevent take.
\c\ Value increased to reflect typical group size.
\d\ Calculated take has been modified to account for increases in actual sighting data to date (Ocean Wind LLC, 2017) based on similar project
  activities.
\e\ Take adjusted to account for possible overlap of the Western North Atlantic southern migratory coastal and offshore stocks (assume a 50 percent of
  each stock).

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 relative cost and 
impact on operations.

Proposed Mitigation Measures

    With NMFS' input during the application process, and as per the 
BOEM Lease, Dominion is proposing the following mitigation measures 
during the proposed marine site characterization surveys.

Marine Mammal Exclusion and Watch Zones

    Marine mammal exclusion zones (EZ) will be established around the 
HRG survey equipment and monitored by protected species observers (PSO) 
during HRG surveys as follows:
    <bullet> 50 m (164.0 ft) EZ for harbor porpoises, which is the 
extent of the largest calculated distance to the potential for onset of 
PTS (Level A harassment);
    <bullet> 100 m (328.1 ft) EZ for ESA-listed large whales (i.e., fin 
whales), which is the largest calculated distance to the potential for 
behavioral harassment (Level B behavioral harassment); and
    <bullet> 500 m (1,640.4 ft) EZ for North Atlantic right whales.
    In addition, PSOs will visually monitor to the extent of the Level 
B zone (100 m (328.1 ft)) for all other marine mammal species not 
listed above.

Visual Monitoring

    Visual monitoring of the established exclusion and monitoring zones 
will be performed by qualified and NMFS-approved PSOs. It will be the 
responsibility of the Lead PSO on duty to communicate the presence of 
marine mammals as well as to communicate and enforce the action(s) that 
are necessary to ensure mitigation and monitoring requirements are 
implemented as appropriate. PSOs will be equipped with binoculars and 
have the ability to estimate distances to marine mammals located in 
proximity to the vessel and/or exclusion zone using range finders. 
Reticulated binoculars will also be available to PSOs for use as 
appropriate based on conditions and visibility to support the siting 
and monitoring of marine species. Digital single-lens reflex camera 
equipment will be used to record sightings and verify species 
identification. During surveys conducted at night, night-vision 
equipment and infrared technology will be available for PSO use.

Pre-Clearance of the Exclusion Zone

    For all HRG survey activities, Dominion would implement a 30-minute 
pre-clearance period of the relevant EZs prior to the initiation of HRG 
survey equipment. During this period the EZs would be monitored by 
PSOs, using the appropriate visual technology for a 30-minute period. 
HRG

[[Page 26985]]

survey equipment would not be initiated if marine mammals are observed 
within or approaching the relevant EZs during this pre-clearance 
period. If a marine mammal were observed within or approaching the 
relevant EZ during the pre-clearance period, ramp-up would not begin 
until the animal(s) has been observed exiting the EZ or until an 
additional time period has elapsed with no further sighting of the 
animal (15 minutes for small delphinoid cetaceans and pinnipeds and 30 
minutes for all other species). This pre-clearance requirement would 
include small delphinoids that approach the vessel (e.g., bow ride). 
PSOs would also continue to monitor the zone for 30 minutes after 
survey equipment is shut down or survey activity has concluded.

Ramp-Up of Survey Equipment

    Where technically feasible, a ramp-up procedure would be used for 
HRG survey equipment capable of adjusting energy levels at the start or 
re-start of HRG survey activities. The ramp-up procedure would be used 
at the beginning of HRG survey activities in order to provide 
additional protection to marine mammals near the survey area by 
allowing them to vacate the area prior to the commencement of survey 
equipment use at full energy. A ramp-up would begin with the power of 
the smallest acoustic equipment at its lowest practical power output 
appropriate for the survey. When technically feasible the power would 
then be gradually turned up and other acoustic sources added in way 
such that the source level would increase gradually.

Shutdown Procedures

    If a marine mammal is observed within or approaching the relevant 
EZ (as described above) an immediate shutdown of the survey equipment 
is required. Subsequent restart of the survey equipment may only occur 
after the animal(s) has either been observed exiting the relevant EZ or 
until an additional time period has elapsed with no further sighting of 
the animal (15 minutes for delphinoid cetaceans and pinnipeds and 30 
minutes for all other species). HRG survey equipment may be allowed to 
continue operating if small delphinids voluntarily approach the vessel 
(e.g., to bow ride) when HRG survey equipment is operating.
    If the HRG equipment shuts down for reasons other than mitigation 
(i.e., mechanical or electronic failure) resulting in the cessation of 
the survey equipment for a period greater than 20 minutes, a 30 minute 
pre-clearance period (as described above) would precede the restart of 
the HRG survey equipment. If the pause is less than less than 20 
minutes, the equipment may be restarted as soon as practicable at its 
full operational level only if visual surveys were continued diligently 
throughout the silent period and the EZs remained clear of marine 
mammals during that entire period. If visual surveys were not continued 
diligently during the pause of 20 minutes or less, a 30-minute pre-
clearance period (as described above) would precede the re-start of the 
HRG survey equipment. Following a shutdown, HRG survey equipment may be 
restarted following pre-clearance of the zones as described above.

Vessel Strike Avoidance

    Dominion will ensure that vessel operators and crew maintain a 
vigilant watch for cetaceans and pinnipeds by slowing down or stopping 
the vessel to avoid striking marine mammals. Survey vessel crew members 
responsible for navigation duties will receive site-specific training 
on marine mammal sighting/reporting and vessel strike avoidance 
measures. Vessel strike avoidance measures will include, but are not 
limited to, the following, as required in the BOEM lease, except under 
circumstances when complying with these requirements would put the 
safety of the vessel or crew at risk:
    <bullet> All vessel operators and crew will maintain vigilant watch 
for cetaceans and pinnipeds, and slow down or stop their vessel to 
avoid striking these protected species;
    <bullet> All vessel operators will comply with 10 kn (18.5 km/hr) 
or less speed restrictions in any DMA. This applies to all vessels 
operating at any time of year. In addition (if applicable, as surveys 
are not anticipated to occur during this time of year), vessels over 
19.8 m (65 ft) operating from November 1 through April 30 will operate 
at speeds of 10 kn or less;
    <bullet> All vessel operators will reduce vessel speed to 10 kn 
(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;
    <bullet> All survey vessels will maintain a separation distance of 
500 m (1640 ft) or greater from any sighted North Atlantic right whale;
    <bullet> If underway, vessels must steer a course away from any 
sighted North Atlantic right whale at 10 kn (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 (1640 ft)) to an underway vessel, the underway vessel must 
reduce speed and shift the engine to neutral. Engines will not be 
engaged until the North Atlantic 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 
100 m;
    <bullet> All vessels will maintain a separation distance of 100 m 
(330 ft) or greater from any sighted non-delphinoid cetacean. If 
sighted, the vessel underway must reduce speed and shift the engine to 
neutral, and must not engage the engines until the non-delphinoid 
cetacean has moved outside of the vessel's path and beyond 100 m. If a 
survey 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;
    <bullet> All vessels will maintain a separation distance of 100 m 
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 survey vessel is 
stationary, the vessel will not engage the engines until the non-
delphinoid cetacean has moved out of the vessel's path and beyond 100 
m.
    <bullet> Any vessel underway remain parallel to a sighted 
delphinoid cetacean's course whenever possible, and avoid excessive 
speed or abrupt changes in direction. Any vessel underway reduces 
vessel speed to 10 kn (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;
    <bullet> All vessels underway will not divert or alter course in 
order to approach any whale, delphinoid cetacean, or pinniped. Any 
vessel underway will avoid excessive speed or abrupt changes in 
direction to avoid injury to the sighted cetacean or pinniped; and
    <bullet> All vessels will maintain a separation distance of 50 m 
(164 ft) or greater from any sighted pinniped.

Seasonal Operating Requirements

    Between watch shifts, members of the monitoring team will consult 
NMFS' North Atlantic right whale reporting systems for the presence of 
North Atlantic right whales throughout survey operations. The proposed 
survey

[[Page 26986]]

activities will occur in the vicinity of the Right Whale Mid-Atlantic 
SMA located at the mouth of the Chesapeake Bay. However, the proposed 
survey start date in August, 2018 is outside of the seasonal mandatory 
speed restriction period for this SMA (November 1 through April 30). 
Members of the monitoring team will monitor the NMFS North Atlantic 
right whale reporting systems for the establishment of a Dynamic 
Management Area (DMA). If NMFS should establish a DMA in the survey 
area, within 24 hours of the establishment of the DMA Dominion will 
work with NMFS to shut down and/or alter the survey activities as 
needed to avoid right whales to the extent possible.
    The proposed mitigation measures are designed to avoid the already 
low potential for injury in addition to some Level B harassment, and to 
minimize the potential for vessel strikes. There are no known marine 
mammal feeding areas, rookeries, or mating grounds in the survey area 
that would otherwise potentially warrant increased mitigation measures 
for marine mammals or their habitat (or both). The proposed survey 
would occur in an area that has been identified as a biologically 
important area for migration for North Atlantic right whales. However, 
given the small spatial extent of the survey area relative to the 
substantially larger spatial extent of the right whale migratory area, 
the survey is not expected to appreciably reduce migratory habitat nor 
to negatively impact the migration of North Atlantic right whales, thus 
additional mitigation to address the proposed survey's occurrence in 
North Atlantic right whale migratory habitat is not warranted. Further, 
we believe the proposed mitigation measures are practicable for the 
applicant to implement.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth, requirements pertaining to 
the monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present 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:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
    <bullet> Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
    <bullet> How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
    <bullet> Mitigation and monitoring effectiveness.

Proposed Monitoring Measures

    As described above, visual monitoring of the EZs and monitoring 
zone will be performed by qualified and NMFS-approved PSOs. Observer 
qualifications will include direct field experience on a marine mammal 
observation vessel and/or aerial surveys and completion of a PSO 
training program, as appropriate. As proposed by the applicant and 
required by BOEM, an observer team comprising a minimum of four NMFS-
approved PSOs operating in shifts, will be employed by Dominion during 
the proposed surveys. PSOs will work in shifts such that no one monitor 
will work more than 4 consecutive hours without a 2 hour break or 
longer than 12 hours during any 24-hour period. During daylight hours 
the PSOs will rotate in shifts of one on and three off, while during 
nighttime operations PSOs will work in pairs. During ramp-up 
procedures, two PSOs will be required. Each PSO will monitor 360 
degrees of the field of vision.
    Also as described above, PSOs will be equipped with binoculars and 
have the ability to estimate distances to marine mammals located in 
proximity to the vessel and/or exclusion zone using range finders. 
Reticulated binoculars will also be available to PSOs for use as 
appropriate based on conditions and visibility to support the siting 
and monitoring of marine species. Digital single-lens reflex camera 
equipment will be used to record sightings and verify species 
identification. During night operations, night-vision equipment, and 
infrared technology will be used to increase the ability to detect 
marine mammals. Position data will be recorded using hand-held or 
vessel global positioning system (GPS) units for each sighting. 
Observations will take place from the highest available vantage point 
on the survey vessel. General 360-degree scanning will occur during the 
monitoring periods, and target scanning by the PSO will occur when 
alerted of a marine mammal presence.
    Data on all PSO observations will be recorded based on standard PSO 
collection requirements. This will include dates and locations of 
survey operations; time of observation, location and weather; details 
of the sightings (e.g., species, age classification (if known), 
numbers, behavior); and details of any observed ``taking'' (behavioral 
disturbances). The data sheet will be provided to NMFS for review and 
approval prior to the start of survey activities. In addition, prior to 
initiation of survey work, all crew members will undergo environmental 
training, a component of which will focus on the procedures for 
sighting and protection of marine mammals. A briefing will also be 
conducted between the survey supervisors and crews, the PSOs, and 
Dominion. The purpose of the briefing will be to establish 
responsibilities of each party, define the chains of command, discuss 
communication procedures, provide an overview of monitoring purposes, 
and review operational procedures.

Proposed Reporting Measures

    Dominion will provide the following reports as necessary during 
survey activities:
    <bullet> The Applicant will contact NMFS within 24 hours of the 
commencement

[[Page 26987]]

of survey activities and again within 24 hours of the completion of the 
activity.
    <bullet> Notification of Injured or Dead Marine Mammals--In the 
unanticipated event that the specified HRG activities lead to an injury 
of a marine mammal (Level A harassment) or mortality (e.g., ship-
strike, gear interaction, and/or entanglement), Dominion would 
immediately cease the specified activities and report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources and the NMFS Greater Atlantic Stranding Coordinator. The 
report would include the following information:
    <bullet> Time, date, and location (latitude/longitude) of the 
incident;
    <bullet> Name and type of vessel involved;
    <bullet> Vessel's speed during and leading up to the incident;
    <bullet> Description of the incident;
    <bullet> Status of all sound source use in the 24 hours preceding 
the incident;
    <bullet> Water depth;
    <bullet> Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    <bullet> Description of all marine mammal observations in the 24 
hours preceding the incident;
    <bullet> Species identification or description of the animal(s) 
involved;
    <bullet> Fate of the animal(s); and
    <bullet> Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the event. NMFS would work with Dominion to minimize 
reoccurrence of such an event in the future. Dominion would not resume 
activities until notified by NMFS.
    In the event that Dominion discovers an injured or dead marine 
mammal and determines that the cause of the injury or death is unknown 
and the death is relatively recent (i.e., in less than a moderate state 
of decomposition), Dominion would immediately report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources and the NMFS Greater Atlantic Stranding Coordinator. The 
report would include the same information identified in the paragraph 
above. Activities would be able to continue while NMFS reviews the 
circumstances of the incident. NMFS would work with Dominion to 
determine if modifications in the activities are appropriate.
    In the event that Dominion discovers an injured or dead marine 
mammal and determines that the injury or death is not associated with 
or related to the activities authorized in the IHA (e.g., previously 
wounded animal, carcass with moderate to advanced decomposition, or 
scavenger damage), Dominion would report the incident to the Chief of 
the Permits and Conservation Division, Office of Protected Resources, 
and the NMFS Greater Atlantic Regional Stranding Coordinator, within 24 
hours of the discovery. Dominion would provide photographs or video 
footage (if available) or other documentation of the stranded animal 
sighting to NMFS. Dominion may continue its operations under such a 
case.
    Within 90 days after completion of survey activities, a final 
technical report will be provided to NMFS that fully documents the 
methods and monitoring protocols, summarizes the data recorded during 
monitoring, estimates the number of marine mammals estimated to have 
been taken during survey activities, and provides an interpretation of 
the results and effectiveness of all mitigation and monitoring. Any 
recommendations made by NMFS must be addressed in the final report 
prior to acceptance by NMFS.

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. 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).
    To avoid repetition, our analysis applies to all the species listed 
in Tables 8 and 9, given that NMFS expects the anticipated effects of 
the proposed survey to be similar in nature.
    NMFS does not anticipate that serious injury or mortality would 
occur as a result of Dominion's proposed survey, even in the absence of 
proposed mitigation. Thus the proposed authorization does not authorize 
any serious injury or mortality. As discussed in the Potential Effects 
section, non-auditory physical effects and vessel strike are not 
expected to occur.
    We expect that most potential takes would be in the form of short-
term Level B behavioral harassment in the form of temporary avoidance 
of the area or decreased foraging (if such activity were occurring), 
reactions that are considered to be of low severity and with no lasting 
biological consequences (e.g., Southall et al., 2007).
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see Potential Effects of the Specified 
Activity on Marine Mammals and their Habitat). Marine mammal habitat 
may be impacted by elevated sound levels, but these impacts would be 
temporary. In addition to being temporary and short in overall 
duration, the acoustic footprint of the proposed survey is small 
relative to the overall distribution of the animals in the area and 
their use of the area. Feeding behavior is not likely to be 
significantly impacted, as no areas of biological significance for 
marine mammal feeding are known to exist in the survey area. Prey 
species are mobile and are broadly distributed throughout the project 
area; therefore, marine mammals that may be temporarily displaced 
during survey 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, 
the availability of similar habitat and resources in the surrounding 
area, and the lack of important or unique marine mammal feeding 
habitat, 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. In addition, there 
are no rookeries or mating or calving areas known to be biologically 
important to marine mammals within the proposed project area. The 
proposed survey area is within a biologically important migratory area 
for North Atlantic right whales (effective March-April and November-
December)

[[Page 26988]]

that extends from Massachusetts to Florida (LaBrecque, et al., 2015). 
Off the coast of Virginia, this biologically important migratory area 
extends from the coast to the just beyond the shelf break. Due to the 
fact that that the proposed survey is temporary and short in overall 
duration, and the fact that the spatial acoustic footprint of the 
proposed survey is very small relative to the spatial extent of the 
available migratory habitat in the area, North Atlantic right whale 
migration is not expected to be impacted by the proposed survey.
    The proposed mitigation measures are expected to reduce the number 
and/or severity of takes by (1) giving animals the opportunity to move 
away from the sound source before HRG survey equipment reaches full 
energy; (2) preventing animals from being exposed to sound levels that 
may otherwise result in injury. Additional vessel strike avoidance 
requirements will further mitigate potential impacts to marine mammals 
during vessel transit to and within the survey area.
    NMFS concludes that exposures to marine mammal species and stocks 
due to Dominion's proposed survey would result in only short-term 
(temporary and short in duration) effects to individuals exposed. 
Marine mammals may temporarily avoid the immediate area, but are not 
expected to permanently abandon the area. Major shifts in habitat use, 
distribution, or foraging success are not expected. NMFS does not 
anticipate the proposed take estimates to impact annual rates of 
recruitment or survival.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
    <bullet> No mortality or serious injury is anticipated or 
authorized;
    <bullet> The anticipated impacts of the proposed activity on marine 
mammals would limited to temporary behavioral changes due to avoidance 
of the area around the survey vessel;
    <bullet> The availability of alternate areas of similar habitat 
value for marine mammals to temporarily vacate the survey area during 
the proposed survey to avoid exposure to sounds from the activity;
    <bullet> The proposed project area does not contain areas of 
significance for feeding, mating or calving;
    <bullet> Effects on species that serve as prey species for marine 
mammals from the proposed survey are not expected;
    <bullet> The proposed mitigation measures, including visual and 
acoustic monitoring and shutdowns, 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 Section 101(a)(5)(D) of the MMPA for specified 
activities other than military readiness activities. The MMPA does not 
define small numbers and so, in practice, where estimated numbers are 
available, NMFS compares the number of individuals taken to the most 
appropriate estimation of abundance of the relevant species or stock in 
our determination of whether an authorization is limited to small 
numbers of marine mammals. Additionally, other qualitative factors may 
be considered in the analysis, such as the temporal or spatial scale of 
the activities.
    The numbers of marine mammals that we propose for authorization to 
be taken, for all species and stocks, would be considered small 
relative to the relevant stocks or populations (less than 10 percent of 
bottlenose dolphin stocks, and less than 1 percent of each of the other 
species and stocks). See Tables 7 and 8. Based on the analysis 
contained herein of the proposed activity (including the proposed 
mitigation and monitoring measures) and the anticipated take of marine 
mammals, NMFS preliminarily finds that small numbers of marine mammals 
will be taken relative to the population size of the affected species 
or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks would 
not have an unmitigable adverse impact on the availability of such 
species or stocks for taking for subsistence purposes.

Endangered Species Act

    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.
    The NMFS Office of Protected Resources is proposing mitigation to 
avoid the incidental take of the species of marine mammals which are 
likely to be present and are listed under the ESA: The North Atlantic 
right and fin whales. Therefore, consultation under section 7 of the 
ESA is not required.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to Dominion for conducting UXO surveys offshore Virginia 
and along the export cable routes from the date of issuance for a 
period of one year, provided the previously mentioned mitigation, 
monitoring, and reporting requirements are incorporated. This section 
contains a draft of the IHA itself. The wording contained in this 
section is proposed for inclusion in the IHA (if issued).
    1. This IHA is valid for a period of one year from the date of 
issuance.
    2. This IHA is valid only for UXO survey activities utilizing HRG 
survey equipment, as specified in the IHA application, in the Atlantic 
Ocean.
    3. General Conditions
    (a) A copy of this IHA must be in the possession of Dominion Energy 
Virginia (Dominion), the vessel operator and other relevant personnel, 
the lead PSO, and any other relevant designees of Dominion operating 
under the authority of this IHA.
    (b) The species authorized for taking are listed in Table 8. The 
taking is limited to the species and numbers listed in Tables 8 and 9. 
Any taking of species not listed in Tables 8 and 9, or exceeding the 
authorized amounts listed, is prohibited and may result in the 
modification, suspension, or revocation of this IHA.
    (c) The taking by injury, serious injury or death of any species of 
marine mammal is prohibited and may result in the modification, 
suspension, or revocation of this IHA.
    (d) Dominion shall ensure that the vessel operator and other 
relevant vessel personnel are briefed on all responsibilities, 
communication procedures, marine mammal monitoring protocols, 
operational procedures, and IHA requirements prior to the start of 
survey activity, and when relevant new personnel join the survey 
operations.
    4. Mitigation Requirements--the holder of this Authorization is 
required

[[Page 26989]]

to implement the following mitigation measures:
    (a) Dominion shall use at least four (4) NMFS-approved protected 
species observers (PSOs) during HRG surveys. The PSOs must have no 
tasks other than to conduct observational effort, record observational 
data, and communicate with and instruct relevant vessel crew with 
regard to the presence of marine mammals and mitigation requirements. 
PSO resumes shall be provided to NMFS for approval prior to 
commencement of the survey.
    (b) Visual monitoring must begin no less than 30 minutes prior to 
initiation of survey equipment and must continue until 30 minutes after 
use of survey equipment ceases.
    (c) Exclusion Zones and Watch Zone--PSOs shall establish and 
monitor marine mammal Exclusion Zones and Watch Zones. PSOs shall 
monitor a marine mammal Watch Zone that shall encompass an area 500 m 
from the survey equipment to encompass the exclusion zone for North 
Atlantic right whales. PSOs shall document and record the behavior of 
all marine mammals observed within the Watch Zone. The Exclusion Zones 
are as follows:
    (i) A 50 m Exclusion Zone for harbor porpoises;
    (ii) a 100 m Exclusion Zone for large ESA-listed whales, except 
North Atlantic right whales (i.e., fin whales); and
    (iii) a 500 m Exclusion Zone for North Atlantic right whales.
    (d) Shutdown requirements--If a marine mammal is observed within, 
entering, or approaching the relevant Exclusion Zones as described 
under 4(c) while geophysical survey equipment is operational, the 
geophysical survey equipment must be immediately shut down.
    (i) Any PSO on duty has the authority to call for shutdown of 
survey equipment. When there is certainty regarding the need for 
mitigation action on the basis of visual detection, the relevant PSO(s) 
must call for such action immediately.
    (ii) If a species for which authorization has not been granted, or, 
a species for which authorization has been granted but the authorized 
number of takes have been met, approaches or is observed within 100 m 
of the survey equipment, shutdown must occur.
    (iii) When a shutdown is called for by a PSO, the shutdown must 
occur and any dispute resolved only following shutdown.
    (iv) Upon implementation of a shutdown, survey equipment may be 
reactivated when all marine mammals have been confirmed by visual 
observation to have exited the relevant Exclusion Zone or an additional 
time period has elapsed with no further sighting of the animal that 
triggered the shutdown (15 minutes for small delphinoid cetaceans and 
pinnipeds and 30 minutes for all other species).
    (v) If geophysical equipment shuts down for reasons other than 
mitigation (i.e., mechanical or electronic failure) resulting in the 
cessation of the survey equipment for a period of less than 20 minutes, 
the equipment may be restarted as soon as practicable if visual surveys 
were continued diligently throughout the silent period and the relevant 
Exclusion Zones are confirmed by PSOs to have remained clear of marine 
mammals during the entire 20 minute period. If visual surveys were not 
continued diligently during the pause of 20 minutes or less, a 30 
minute pre-clearance period shall precede the restart of the 
geophysical survey equipment as described in 4(e). If the period of 
shutdown for reasons other than mitigation is greater than 20 minutes, 
a pre-clearance period shall precede the restart of the geophysical 
survey equipment as described in 4(e).
    (e) Pre-clearance observation--30 minutes of pre-clearance 
observation shall be conducted prior to initiation of geophysical 
survey equipment. geophysical survey equipment shall not be initiated 
if marine mammals are observed within or approaching the relevant 
Exclusion Zones as described under 4(d) during the pre-clearance 
period. If a marine mammal is observed within or approaching the 
relevant Exclusion Zone during the pre-clearance period, geophysical 
survey equipment shall not be initiated until the animal(s) is 
confirmed by visual observation to have exited the relevant Exclusion 
Zone or until an additional time period has elapsed with no further 
sighting of the animal (15 minutes for small delphinoid cetaceans and 
pinnipeds and 30 minutes for all other species).
    (f) Ramp-up--when technically feasible, survey equipment shall be 
ramped up at the start or re-start of survey activities. Ramp-up will 
begin with the power of the smallest acoustic equipment at its lowest 
practical power output appropriate for the survey. When technically 
feasible the power will then be gradually turned up and other acoustic 
sources added in way such that the source level would increase 
gradually.
    (g) Vessel Strike Avoidance--Vessel operator and crew must maintain 
a vigilant watch for all marine mammals and slow down or stop the 
vessel or alter course, as appropriate, to avoid striking any marine 
mammal, unless such action represents a human safety concern. Survey 
vessel crew members responsible for navigation duties shall receive 
site-specific training on marine mammal sighting/reporting and vessel 
strike avoidance measures. Vessel strike avoidance measures shall 
include the following, except under circumstances when complying with 
these requirements would put the safety of the vessel or crew at risk:
    (i) The vessel operator and crew shall maintain vigilant watch for 
cetaceans and pinnipeds, and slow down or stop the vessel to avoid 
striking marine mammals;
    (ii) The vessel operator will reduce vessel speed to 10 kn (18.5 
km/hr) or less when any large whale, any mother/calf pairs, whale or 
dolphin pods, or larger assemblages of non-delphinoid cetaceans are 
observed near (within 100 m (330 ft)) an underway vessel;
    (iii) The survey vessel will maintain a separation distance of 500 
m (1640 ft) or greater from any sighted North Atlantic right whale;
    (iv) If underway, the vessel must steer a course away from any 
sighted North Atlantic right whale at 10 kn (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 100 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 North Atlantic right whale has moved outside of the 
vessel's path and beyond 100 m. If stationary, the vessel must not 
engage engines until the North Atlantic right whale has moved beyond 
100 m;
    (v) The vessel will maintain a separation distance of 100 m (330 
ft) or greater from any sighted non-delphinoid cetacean. If sighted, 
the vessel underway must reduce speed and shift the engine to neutral, 
and must not engage the engines until the non-delphinoid cetacean has 
moved outside of the vessel's path and beyond 100 m. If a survey 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;
    (vi) The vessel will maintain a separation distance of 50 m (164 
ft) or greater from any sighted delphinoid cetacean. Any vessel 
underway remain parallel to a sighted delphinoid cetacean's course 
whenever possible, and avoid excessive speed or abrupt changes in 
direction. Any vessel underway reduces vessel speed to 10 kn (18.5 km/
hr) or less when pods (including mother/calf pairs) or large 
assemblages of delphinoid cetaceans are

[[Page 26990]]

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;
    (vii) All vessels underway will not divert or alter course in order 
to approach any whale, delphinoid cetacean, or pinniped. Any vessel 
underway will avoid excessive speed or abrupt changes in direction to 
avoid injury to the sighted cetacean or pinniped; and
    (viii) All vessels will maintain a separation distance of 50 m (164 
ft) or greater from any sighted pinniped.
    (ix) The vessel operator will comply with 10 kn (18.5 km/hr) or 
less speed restrictions in any Seasonal Management Area per NMFS 
guidance.
    (x) If NMFS should establish a Dynamic Management Area (DMA) in the 
area of the survey, within 24 hours of the establishment of the DMA, 
DWW shall contact the NMFS Office of Protected Resources to determine 
whether survey location and/or activities should be altered to avoid 
North Atlantic right whales.
    5. Monitoring Requirements--The Holder of this Authorization is 
required to conduct marine mammal visual monitoring during geophysical 
survey activity. Monitoring shall be conducted in accordance with the 
following requirements:
    (a) A minimum of four NMFS-approved PSOs, operating in shifts, 
shall be employed by Dominion during geophysical surveys.
    (b) Observations shall take place from the highest available 
vantage point on the survey vessel. General 360-degree scanning shall 
occur during the monitoring periods, and target scanning by PSOs will 
occur when alerted of a marine mammal presence.
    (c) PSOs shall be equipped with binoculars and have the ability to 
estimate distances to marine mammals located in proximity to the vessel 
and/or Exclusion Zones using range finders. Reticulated binoculars will 
also be available to PSOs for use as appropriate based on conditions 
and visibility to support the sighting and monitoring of marine 
species. Digital single-lens reflex camera equipment will be used to 
record sightings and verify species identification.
    (d) During night surveys, night-vision equipment and infrared 
technology shall be used. Specifications for night-vision and infrared 
equipment shall be provided to NMFS for review and acceptance prior to 
start of surveys.
    (e) PSOs operators shall work in shifts such that no one monitor 
will work more than 4 consecutive hours without a 2 hour break or 
longer than 12 hours during any 24-hour period. During daylight hours 
the PSOs shall rotate in shifts of 1 on and 3 off. During ramp-up 
procedures and nighttime operations PSOs shall work in pairs.
    (f) Position data shall be recorded using hand-held or vessel 
global positioning system (GPS) units for each sighting.
    (g) A briefing shall be conducted between survey supervisors and 
crews, PSOs, and Dominion to establish responsibilities of each party, 
define chains of command, discuss communication procedures, provide an 
overview of monitoring purposes, and review operational procedures.
    (h) PSO Qualifications shall include direct field experience on a 
marine mammal observation vessel and/or aerial surveys.
    (i) Data on all PSO observations shall be recorded based on 
standard PSO collection requirements. PSOs must use standardized data 
forms, whether hard copy or electronic. The following information shall 
be reported:
    (i) PSO names and affiliations
    (ii) Dates of departures and returns to port with port name
    (iii) Dates and times (Greenwich Mean Time) of survey effort and 
times corresponding with PSO effort
    (iv) Vessel location (latitude/longitude) when survey effort begins 
and ends; vessel location at beginning and end of visual PSO duty 
shifts
    (v) Vessel heading and speed at beginning and end of visual PSO 
duty shifts and upon any line change
    (vi) Environmental conditions while on visual survey (at beginning 
and end of PSO shift and whenever conditions change significantly), 
including wind speed and direction, Beaufort sea state, Beaufort wind 
force, swell height, weather conditions, cloud cover, sun glare, and 
overall visibility to the horizon
    (vii) Factors that may be contributing to impaired observations 
during each PSO shift change or as needed as environmental conditions 
change (e.g., vessel traffic, equipment malfunctions)
    (viii) Survey activity information, such as acoustic source power 
output while in operation, number and volume of airguns operating in 
the array, tow depth of the array, and any other notes of significance 
(i.e., pre-ramp-up survey, ramp-up, shutdown, testing, shooting, ramp-
up completion, end of operations, streamers, etc.)
    (ix) If a marine mammal is sighted, the following information 
should be recorded:
    (A) Watch status (sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
    (B) PSO who sighted the animal;
    (C) Time of sighting;
    (D) Vessel location at time of sighting;
    (E) Water depth;
    (F) Direction of vessel's travel (compass direction);
    (G) Direction of animal's travel relative to the vessel;
    (H) Pace of the animal;
    (I) Estimated distance to the animal and its heading relative to 
vessel at initial sighting;
    (J) Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified); also note the composition 
of the group if there is a mix of species;
    (K) Estimated number of animals (high/low/best) ;
    (L) Estimated number of animals by cohort (adults, yearlings, 
juveniles, calves, group composition, etc.);
    (M) Description (as many distinguishing features as possible of 
each individual seen, including length, shape, color, pattern, scars or 
markings, shape and size of dorsal fin, shape of head, and blow 
characteristics);
    (N) Detailed behavior observations (e.g., number of blows, number 
of surfaces, breaching, spyhopping, diving, feeding, traveling; as 
explicit and detailed as possible; note any observed changes in 
behavior);
    (O) Animal's closest point of approach and/or closest distance from 
the center point of the acoustic source;
    (P) Platform activity at time of sighting (e.g., deploying, 
recovering, testing, data acquisition, other); and
    (Q) Description of any actions implemented in response to the 
sighting (e.g., delays, shutdown, ramp-up, speed or course alteration, 
etc.) and time and location of the action.
    6. Reporting--a technical report shall be provided to NMFS within 
90 days after completion of survey activities that fully documents the 
methods and monitoring protocols, summarizes the data recorded during 
monitoring, estimates the number of marine mammals that may have been 
taken during survey activities, describes the effectiveness of the 
various mitigation techniques and provides an interpretation of the 
results and effectiveness of all monitoring tasks. Any recommendations 
made by NMFS shall be addressed in the final report prior to acceptance 
by NMFS.
    (a) Reporting injured or dead marine mammals:
    (i) In the event that the specified activity clearly causes the 
take of a marine mammal in a manner not

[[Page 26991]]

prohibited by this IHA (if issued), such as serious injury or 
mortality, Dominion shall immediately cease the specified activities 
and immediately report the incident to NMFS. The report must include 
the following information:
    (A) Time, date, and location (latitude/longitude) of the incident;
    (B) Vessel's speed during and leading up to the incident;
    (C) Description of the incident;
    (D) Status of all sound source use in the 24 hours preceding the 
incident;
    (E) Water depth;
    (F) Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    (G) Description of all marine mammal observations in the 24 hours 
preceding the incident;
    (H) Species identification or description of the animal(s) 
involved;
    (I) Fate of the animal(s); and
    (J) Photographs or video footage of the animal(s).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS will work with Dominion to 
determine what measures are necessary to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. Dominion may not 
resume their activities until notified by NMFS.
    (ii) In the event that Dominion discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition), Dominion shall immediately report 
the incident to NMFS. The report must include the same information 
identified in condition 6(b)(i) of this IHA. Activities may continue 
while NMFS reviews the circumstances of the incident. NMFS will work 
with Dominion to determine whether additional mitigation measures or 
modifications to the activities are appropriate.
    (iii) In the event that Dominion discovers an injured or dead 
marine mammal, and the lead PSO determines that the injury or death is 
not associated with or related to the specified activities (e.g., 
previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), Dominion shall report the incident 
to NMFS within 24 hours of the discovery. Dominion shall provide 
photographs or video footage or other documentation of the sighting to 
NMFS.
    7. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein, or if 
NMFS determines the authorized taking is having more than a negligible 
impact on the species or stock of affected marine mammals.

Request for Public Comments

    We request comment on our analyses, the draft authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed marine 
site characterization surveys. Please include with your comments any 
supporting data or literature citations to help inform our final 
decision on the request for MMPA authorization.
    On a case-by-case basis, NMFS may issue a one-year renewal IHA 
without additional notice when (1) another year of identical or nearly 
identical activities as described in the Specified Activities section 
is planned, or (2) the activities would not be completed by the time 
the IHA expires and renewal would allow completion of the activities 
beyond that described in the Dates and Duration section, provided all 
of the following conditions are met:
    <bullet> A request for renewal is received no later than 60 days 
prior to expiration of the current IHA.
    <bullet> The request for renewal must include the following:
    (1) An explanation that the activities to be conducted beyond the 
initial dates either are identical to the previously analyzed 
activities or include changes so minor (e.g., reduction in pile size) 
that the changes do not affect the previous analyses, take estimates, 
or mitigation and monitoring requirements; and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    <bullet> 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 remain the same and appropriate, 
and the original findings remain valid.

    Dated: June 6, 2018.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2018-12471 Filed 6-8-18; 8:45 am]
 BILLING CODE 3510-22-P


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