Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Site Characterization Surveys off the Coast of North Carolina, 17384-17405 [2019-08361]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 84, Number 80 (Thursday, April 25, 2019)]
[Notices]
[Pages 17384-17405]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-08361]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG612


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Site Characterization Surveys off 
the Coast of North Carolina

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from Avangrid Renewables, LLC for 
authorization to take marine mammals incidental to high-resolution 
geophysical (HRG) survey investigations associated with marine site 
characterization activities off the coast of North Carolina in the area 
of the Commercial Lease of Submerged Lands for Renewable Energy 
Development on the Outer Continental Shelf (OCS-A 0508) (the Lease 
Area) and the coastal waters off North Carolina and Virginia where one 
or more cable route corridors 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 
is also requesting comments on a possible one-year renewal that could 
be issued under certain circumstances and if all requirements are met, 
as described in Request for Public Comments at the end of this notice. 
NMFS will consider public comments prior to making any final decision 
on the issuance of the requested MMPA authorizations and agency 
responses will be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than May 28, 
2019.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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: Rob Pauline, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. In case of 
problems accessing these documents, please call the contact listed 
above.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings

[[Page 17385]]

are made and either regulations are issued or, if the taking is limited 
to harassment, a notice of a proposed incidental take authorization may 
be provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other means of effecting the least practicable adverse 
impact on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of such species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the monitoring and 
reporting of such takings must be set forth.

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.
    NMFS is preparing an Environmental Assessment (EA) to consider the 
environmental impacts associated with the issuance of the proposed IHA. 
NMFS' EA will be made available at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
    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 October 4, 2018, NMFS received a request from Avangrid for an 
IHA to take marine mammals incidental to HRG survey investigations off 
the coast of North Carolina in the OCS-A 0508 Lease Area and in the 
coastal waters of Virginia and North Carolina where one or more cable 
route corridors will be established to support the development of an 
offshore wind project. The application was deemed adequate and complete 
on February 21, 2019. Avangrid's request is for take of small numbers 
of nine species by Level B harassment only. Neither Avangrid nor NMFS 
expects serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    The purpose of the marine site characterization survey is to 
support the siting, design, and deployment of up to three 
meteorological data buoy deployment areas and obtain a baseline 
assessment of seabed/sub-surface soil conditions in the Lease Area and 
cable route corridors to support the siting of a proposed wind farm. 
Underwater sound resulting from use of HRG equipment for site 
characterization purposes can have the potential to result in 
incidental take of marine mammals. The survey area extends along the 
coast from near the mouth of the Chesapeake Bay to Currituck, North 
Carolina. Up to 37 days of active HRG survey operations are planned and 
could take place at time during the one year authorization period. This 
take of marine mammals is anticipated to be in the form of harassment 
only; no serious injury or mortality is anticipated, nor is any 
proposed for authorization here.

Dates and Duration

    HRG Surveys are anticipated to commence no earlier than June 1, 
2019, and will last for approximately 37 days. This survey schedule is 
based on 24-hour operations and includes estimated weather down time. 
The proposed surveys are planned to take place during the summer 
months. The IHA would be effective for one year.

Specific Geographic Region

    Avangrid's survey activities will occur in the approximately 
122,317-acre Lease Area located approximately 31.3 nautical miles off 
the coast of Currituck, North Carolina, in Federal waters of the United 
States (see Figure 1 in Application). In addition, multiple cable route 
corridors will be surveyed within the area identified in Figure 1 in 
the Application. Each survey corridor is anticipated to be 30 to 70 
nautical miles and extend from the lease area to landfall locations to 
be determined. For the purpose of this proposed IHA, the survey area is 
considered to be the Lease Area and cable route corridors. Water depths 
across the survey area are relatively shallow. Lease Area depths range 
from approximately 20 to 50 m (66 to 164 feet (ft)) while the cable 
route corridors will extend to shallow water close to landfall.

Detailed Description of Specific Activity

    HRG surveys are employed to detect geohazards, archaeological 
resources, certain types of benthic communities, and to assess seafloor 
suitability for supporting structures such as platforms, pipelines, 
cables, and wind turbines. These surveys for renewable energy occur in 
shallow waters. HRG surveys typically use only electromechanical 
sources such as side-scan sonars; boomer, sparker, and chirp sub-bottom 
profilers; and multibeam depth sounders, some of which are expected to 
be beyond the functional hearing range of marine mammals or would be 
detectable only at very close range.\1\
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    \1\ HRG surveys are distinguishable from deep penetration 
seismic surveys, which occur in deeper offshore waters and are 
associated with oil and gas exploration. Seismic surveys are not 
used for renewable energy development. Deep penetration seismic 
airgun surveys are conducted by vessels towing an array of airguns 
that emit acoustic energy pulses into the seafloor, and which may 
occur over long durations and over large areas. In contrast with HRG 
surveys, airguns are considered a low-frequency source since most of 
its acoustic energy is radiated at frequencies below 200 Hz.
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    Marine site characterization surveys will include the following HRG 
survey activities:
     Multibeam echosounder use to determine site bathymetry and 
elevations;
     Seafloor imaging (sidescan sonar survey) for seabed 
sediment classification purposes, to identify natural and man-made 
acoustic targets resting on the bottom as well as any anomalous 
features;
     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);
     Medium penetration sub-bottom profiler (sparker) to map 
deeper subsurface stratigraphy as needed (soils down to 75 to 100 m 
(246 to 328 ft) below seabed);
     Magnetic intensity measurements for detecting local 
variations in regional magnetic field from geological strata and 
potential ferrous objects on and below the bottom; and
     Benthic Drop-down Video (DDV) and grab samples to inform 
and confirm geophysical interpretations and to provide further detail 
on areas of potential benthic and ecological interest.
    Note that take of marine mammals is not associated with use of 
magnetic intensity measurement devices, DDV, or grab sample equipment.
    A technical report conducted by the Naval Undersea Warfare Center 
(NUWC), through support from the Bureau of Ocean Energy Management 
(BOEM) and the United States Geological Survey, published measurements 
of the acoustic output from a variety of sources used during HRG 
surveys (Crocker and Fratantonio,

[[Page 17386]]

2016). The HRG test equipment were operated over a wide range of 
settings with different acoustic levels measured. As a conservative 
measure, the highest sound source levels and pulse duration for each 
piece of equipment were applied to the analysis herein. Representative 
equipment and source level characteristics are listed in Table 1. The 
exact make and model of the listed HRG equipment may vary depending on 
availability but will be equivalent to those described here.

                                                             Table 1--Measured Source Levels of Representative HRG Survey Equipment
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                                           Representative HRG survey                                   Peak source     RMS source    Pulse duration    Beam width
               HRG system                          equipment               Operating frequencies          level           level           (ms)          (degree)             Signal type
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Subsea Positioning/USBL.\1\               Sonardyne Ranger 2 USBL....                     35-50 kHz      200 dBpeak       188 dBRMS              16             180  FM Chirp.
Sidescan Sonar..........................  Klein 3900 Sidescan Sonar..                      445 kHz/      226 dBpeak       220 dBRMS  0.016 to 0.100          1 to 2  Impulse.
                                                                                            900 kHz
Shallow penetration sub-bottom profiler.  EdgeTech 512i..............                 0.4 to 12 kHz      186 dBpeak       179 dBRMS     1.8 to 65.8        51 to 80  FM Chirp.
Parametric Shallow penetration sub-       Innomar parametric SES-2000                 85 to 115 kHz      243 dBpeak       236 dBRMS       0.07 to 2               1  FM Chirp.
 bottom profiler.                          Standard.
Medium penetration sub-bottom profiler..  SIG ELC 820 Sparker........                0.9 to 1.4 kHz      215 dBpeak       206 dBRMS             0.8          \2\ 30  Impulse.
Multibeam Echo Sounder..................  Reson T20-P................               200/300/400 kHz      227 dBpeak       221 dBRMS          2 to 6      1.8 0.2[deg]
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1: Equipment information not provided in Crocker and Fratantonio, 2016. Information provided is based on manufacturer specifications.
2: A beamwidth of 30 degrees from horizontal is considered typical for electrode sparker technologies. Specific beamwidth information is not readily available from the equipment manufacturer.

    Note that the operating frequencies of both the multibeam echo 
sounder and side-scan sonar occur outside the hearing range of marine 
mammals. Since there are no impacts to cetaceans associated with use of 
this equipment, these sources are not considered further in this 
document.
    The survey activities will be supported by a vessel, or vessels, 
capable of maintaining course and a survey speed of approximately 4 
nautical miles per hour (knots, 7 kilometers per hour (km/hr)) while 
transiting survey lines. Surveys will be conducted along tracklines 
spaced 150 m (98 ft) apart, with tie-lines spaced every 500 m (1640 
ft). Several survey vessels may be used simultaneously, but it is more 
likely that only a single vessel would conduct surveys at any one time.
    To minimize cost, the duration of survey activities, and the period 
of potential impact on marine species while surveying, Avangrid has 
proposed conducting continuous HRG survey operations 24 hours per day. 
Based on 24-hour operations, the estimated duration of the HRG survey 
activities would be approximately 37 days. Additional time (up to 30 
days) may be required to obtain full multibeam coverage in shallow 
water areas, however the multibeam sensor operates at frequencies above 
the functional hearing ranges of marine mammals; therefore take of 
marine mammals is not expected as a result of multibeam-only survey 
activity, and multibeam-only survey activity is not analyzed further in 
this document.
    The deployment of HRG survey equipment, including the use of sound-
producing equipment operating below 200 kHz (e.g., sub-bottom 
profilers), may have the potential to result in harassment of marine 
mammals. Based on the frequency ranges of the potential equipment to be 
used in support of the HRG survey activities; the ultra-short baseline 
(USBL) positioning system and the sub-bottom profilers (shallow and 
medium penetration) operate within the established marine mammal 
hearing ranges and have the potential to result in Level B harassment 
of marine mammals.
    NMFS has previously issued IHAs for HRG surveys conducted in the 
Atlantic Ocean, off the east coast of the United States. Most of these 
have occurred in the coastal waters of southern New England, although 
NMFS recently issued an IHA for an HRG survey investigating unexploded 
ordnance (UXO) off the coast of Virginia as part of an offshore wind 
project (83 FR 39062, August 8, 2018). Marine mammal monitoring reports 
submitted after completion of HRG surveys indicated that authorized 
take numbers have never been exceeded.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's

[[Page 17387]]

website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists species with expected potential for take in the 
survey area and summarizes information related to the population or 
stock, including regulatory status under the MMPA and ESA and potential 
biological removal (PBR), where known. For taxonomy, we follow 
Committee on Taxonomy (2018). PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS's 
SARs). While no mortality or serious injury is anticipated or 
authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Atlantic 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 SARs (Hayes et al., 2018) and 
draft 2018 SARs (available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draftmarine-mammal-stock-assessment-reports).

                                           Table 2--Marine Mammal Species That May Occur Near the Survey Area
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                                                                                                       Stock abundance
                                                                                 ESA/MMPA status;      (CV, Nmin, most                      Annual M/SI
          Common name              Scientific name            Stock            strategic (Y/N) \1\     recent abundance         PBR             \3\
                                                                                                         survey) \2\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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                                                                    Family Balaenidae
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North Atlantic Right whale.....  Eubalaena           Western North Atlantic   E/D; Y                 451 (0; 445; 2017)              0.9            5.56
                                  glacialis.          (WNA).
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                                                            Family Balaenopteridae (rorquals)
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Humpback whale.................  Megaptera           Gulf of Maine..........  -/-; N                 896 (0; 896; 2012)             14.6             9.8
                                  novaeangliae.
Fin whale......................  Balaenoptera        WNA....................  E/D; Y                 1,618 (0.33; 1,234;             2.5             2.5
                                  physalus.                                                           2011)
Sei whale......................  Balaenoptera        Nova Scotia............  E/D; Y                 357 (0.52; 236                  0.5             0.6
                                  borealis.
Minke whale....................  Balaenoptera        Canadian East Coast....  -/-; N                 2,591 (0.81; 1,425               14             7.5
                                  acutorostrata.
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                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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                                                                   Family Delphinidae
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Short-finned pilot whale.......  Globicephala        WNA....................  -/-; Y                 21,515 (0.37;                   159             192
                                  macrorhyn-.                                                         15,913:2011)
                                  chus.............
Long-finned pilot whale........  Globicephala melas  WNA....................  -/-; Y                 5,636 (0.63; 3,464)              35              38
Bottlenose dolphin.............  Tursiops spp......  WNA Offshore...........  -/-; N                 77,532 (0.40;                   561            39.4
                                                                                                      56053; 2016)
                                                     WNA Southern Migratory   -/-; Y                 3,751 (0.060;                    23          0-12.3
                                                      Coastal.                                        2,353; 2017)
Short beaked common dolphin....  Delphinus delphis.  WNA....................  -/-; N                 70,184 (0.28;                   557             406
                                                                                                      55,690;2011)
Atlantic white-sided dolphin...  Lagenorhynchus      WNA....................  -/-; N                 48,819 (0.61;                   304              30
                                  acutus.                                                             30,403; 2011)
Atlantic spotted dolphin.......  Stenella frontalis  WNA....................  -/-: N                 44,715 (0.43;                   316               0
                                                                                                      31,610; 2013)
Risso's dolphin................  Grampus griseus...  WNA....................  -/-; N                 18,250 (0.5;                    126            49.7
                                                                                                      12,619; 2011)
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                                                             Family Phocoenidae (porpoises)
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Harbor porpoise................  Phocoena phocoena.  Gulf of Maine/Bay of     -/-; N                 79,833 (0.32;                   706             255
                                                      Fundy.                                          61,415; 2011)
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1--Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.

[[Page 17388]]

 
2--NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
3--These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
  fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.

    Three marine mammal species that are listed under the Endangered 
Species Act (ESA) may be present in the survey area: The North Atlantic 
right whale, fin whale, and sei whale. However, NMFS is not proposing 
authorized take of any of these species. The proposed authorization of 
take for 10 species (with 11 managed stocks) is described in the 
Estimated Take section. However, the temporal and/or spatial occurrence 
of Bryde's whale, blue whale and sperm whale is such that take is not 
expected to occur. While the BOEM Environmental Assessment (EA) for the 
North Carolina Wind Energy Areas (2015) indicates that Bryde's whales 
may be present during fall and winter, their presence in the survey 
area is very rare and unlikely during the summer (BOEM 2015). The blue 
whale is an occasional visitor along the northeast Atlantic coast. 
Sightings of blue whales off Cape Cod, Massachusetts, in summer and 
fall may represent the southern limit of the feeding range of the 
western North Atlantic stock that feeds primarily off the Canadian 
coast. The sperm whale occurs on the continental shelf edge, over the 
continental slope, and into mid-ocean regions in deeper waters than 
those in the project area. (NMFS 2015). Because the potential for the 
Bryde's whale, blue whale and sperm whale to occur within the survey 
area is unlikely, these species will not be described further. In 
addition, while strandings 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 during the summer and fall (Hayes et al 
2018). Winter haulout sites for harbor seals have been identified 
within the Chesapeake Bay region and Outer Banks beaches, however the 
seals are only occasionally sited as far south as the Carolinas and are 
not likely to be present during spring and summer months during which 
survey activities are planned (Hayes et al. 2018). In addition, coastal 
Virginia and North Carolina represent the southern extent of the 
habitat range for gray seals, with few stranding records reported for 
the even more southern waters of North Carolina and sightings occurring 
only during winter months as far south as New Jersey (Waring et al. 
2016). Therefore, these seal species will not be described further in 
this analysis.

North Atlantic Right Whale

    The North Atlantic right whale was listed as a Federal endangered 
species in 1970. The right whale is a strongly migratory species, with 
some portion of the population moving annually between high-latitude 
feeding grounds and low latitude calving and breeding grounds. The 
present range of the western North Atlantic right whale population 
extends from the southeastern United States, which is utilized for 
wintering and calving by some individuals, to summer feeding and 
nursery grounds between New England and the Bay of Fundy and the Gulf 
of St. Lawrence (Kenney 2002; Waring et al. 2011). The winter 
distribution of much of the population that does not take part in 
seasonal migration is largely unknown, although offshore surveys have 
reported 1 to 13 detections annually in northeastern Florida and 
southeastern Georgia (Waring et al. 2013). Right whales have been 
observed in or near Virginia and North Carolina waters from October 
through December, as well as in February and March, which coincides 
with the migratory time frame for this species (Knowlton et al. 2002). 
A few events of right whale calving have been documented from shallow 
coastal areas and bays (Kenney 2002). Some evidence provided through 
acoustic monitoring suggests that not all individuals of the population 
participate in annual migrations, with a continuous presence of right 
whales occupying their entire habitat range throughout the year, 
particularly north of Cape Hatteras (Davis et al. 2017). However, an 
analysis of the composition and distribution of individual right whale 
sightings archived by the North Atlantic Right Whale Consortium from 
1998 through 2015 suggests that very few whales would be present year-
round. These data also recognize changes in population distribution 
throughout the right whale habitat range that could be due to 
environmental or anthropogenic effects, a response to short-term 
changes in the environment, or a longer-term shift in the right whale 
distribution cycle (Davis et al. 2017).
    The proposed survey area is part of a migratory Biologically 
Important Area (BIA) 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. Additionally, NMFS' regulations at 50 CFR 
224.105 impose vessel speed limits in designated Seasonal Management 
Areas (SMA) in nearshore waters of the Mid-Atlantic Bight. SMAs were 
developed to reduce the threat of collisions between ships and right 
whales around their migratory route and calving grounds. NMFS requires 
that all vessels 65 ft (19.8 m) or longer must travel at 10 knots or 
less within the right whale SMA from November 1 through April 30 when 
right whales are most likely to pass through these waters (NOAA 2010). 
A small section of the cable routing area overlaps spatially with the 
Chesapeake Bay SMA.
    The western North Atlantic population demonstrated overall growth 
of 2.8 percent per year between 1990 and 2010 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). In 2018, no new North Atlantic right whale calves were 
documented in their calving grounds; this represented the first time 
since annual NOAA aerial surveys began in 1989 that no new right whale 
calves were observed. However, in 2019 at least seven right whale 
calves have been identified (Savio 2019).
    Elevated North Atlantic right whale mortalities have occurred since 
June 7, 2017. A total of 20 confirmed dead stranded whales (12 in 
Canada; 8 in the United States), have been documented to date. This 
event has been declared an Unusual Mortality Event (UME), with human 
interactions (i.e., fishery-related entanglements and vessel strikes) 
identified as the most likely cause. More information is available 
online at: https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2018-north-atlantic-right-whale-unusual-mortality-event.

Humpback Whale

    Humpback whales are found worldwide in all oceans. In 1973, the

[[Page 17389]]

ESA listed humpbacks as endangered. NMFS recently evaluated the status 
of the species, and on September 8, 2016, NMFS divided the species into 
14 distinct population segments (DPS), removed the current species-
level listing, and in its place listed four DPSs as endangered and one 
DPS as threatened (81 FR 62259; September 8, 2016). The remaining nine 
DPSs were not listed. The West Indies DPS, which is not listed under 
the ESA, is the only DPS of humpback whale that is expected to occur in 
the survey area. The best estimate of population abundance for the West 
Indies DPS is 12,312 individuals, as described in the NMFS Status 
Review of the Humpback Whale under the Endangered Species Act 
(Bettridge et al., 2015). This abundance estimate, for the West Indies 
breeding population, is more appropriate for use in reference to whales 
that may occur in the survey area than is the estimate given in Table 
2, which is specific to the Gulf of Maine feeding population.
    Since January 2016, elevated humpback whale mortalities have 
occurred along the Atlantic coast from Maine through Florida. The event 
has been declared a UME. Partial or full necropsy examinations have 
been conducted on approximately half of the 88 known cases. A portion 
of the whales have shown evidence of pre-mortem vessel strike; however, 
this finding is not consistent across all of the whales examined so 
more research is needed. NOAA is consulting with researchers that are 
conducting studies on the humpback whale populations, and these efforts 
may provide information on changes in whale distribution and habitat 
use that could provide additional insight into how these vessel 
interactions occurred. More detailed information is available at: 
https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2018-humpback-whale-unusual-mortality-event-along-atlantic-coast#causes-of-the-humpback-whale-ume (accessed February 25, 2019). Three previous 
UMEs involving humpback whales have occurred since 2000, in 2003, 2005, 
and 2006.
    During winter, the majority of humpback whales from North Atlantic 
feeding areas mate and calve in the West Indies, where spatial and 
genetic mixing among feeding groups occurs, though significant numbers 
of animals are found in mid- and high-latitude regions at this time and 
some individuals have been sighted repeatedly within the same winter 
season, indicating that not all humpback whales migrate south every 
winter (Waring et al., 2017). 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. 2013). 
Humpbacks typically occur within the Mid-Atlantic region during fall, 
winter, and spring months (Waring et al. 2012).

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., 2017). Fin whales are present north of 35-degree latitude in 
every season and are broadly distributed throughout the western North 
Atlantic for most of the year, though densities vary seasonally (Waring 
et al., 2017). They are found in small groups of up to five individuals 
(Brueggeman et al., 1987).
    Present threats to fin whales are similar to other whale species, 
namely fishery entanglements and vessel strikes. Fin whales seem less 
likely to become entangled than other whale species. Glass et al. 
(2008) reported that between 2002 and 2006, fin whales belonging to the 
Gulf of Maine population were involved in only eight confirmed 
entanglements with fishery equipment. Furthermore, Nelson et al. (2007) 
reported that fin whales exhibited a low proportion of entanglements 
(eight reported events) during their 2001 to 2005 study along the 
western Atlantic. On the other hand, vessel strikes may be a more 
serious threat to fin whales. Eight and 10 confirmed vessel strikes 
with fin whales were reported by Glass et al. (2008) and Nelson et al. 
(2007), respectively. This level of incidence was similar to that 
exhibited by the other whales studied. Conversely, a study compiling 
whale/vessel strike reports from historical accounts, recent whale 
strandings, and anecdotal records by Laist et al. (2001) reported that 
of the 11 great whale species studied, fin whales were involved in 
collisions most frequently.
    Fin whales are present in the Mid-Atlantic region during all four 
seasons, although sightings data indicate that they are more prevalent 
during winter, spring, and summer (Waring et al 2012). While fall is 
the season of lowest overall abundance off Virginia and North Carolina, 
they do not depart the area entirely.

Sei Whale

    The sei whale is a widespread species in the world's temperate, 
subpolar, subtropical, and tropical marine waters. NOAA Fisheries 
considers sei whales occurring from the U.S. East Coast to Cape Breton, 
Nova Scotia, and east to 42[deg] W as the ``Nova Scotia stock'' of sei 
whales (Waring et al. 2016; Hayes et al. 2018). Sei whales occur in 
deep water characteristic of the continental shelf edge throughout 
their range (Hain et al. 1985). They are often found in pairs 
(Schilling, 1992). In the Northwest Atlantic, it is speculated that the 
whales migrate from south of Cape Cod along the eastern Canadian coast 
in June and July, and return on a southward migration again in 
September and October (Waring et al. 2014; 2016). The sei whale is most 
common on Georges Bank and into the Gulf of Maine/Bay of Fundy region 
during spring and summer, primarily in deeper waters.
    There is limited information on the stock identity of sei whales in 
the North Atlantic and insufficient data to determine trends of the 
Nova Scotian sei whale population (Hayes et al. 2018). A final recovery 
plan for the sei whale was published in 2011 (NOAA Fisheries 2011). Sei 
whale occurrence is relatively rare in the survey area.

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., 2017). This species generally occupies waters less than 
100 m deep on the continental shelf (Waring et al., 2017).
    Since January 2017, elevated minke whale strandings have occurred 
along the Atlantic coast from Maine through South Carolina, with 
highest numbers in Massachusetts, Maine, and New York. As of September 
30, 2018, partial or full necropsy examinations have been conducted on 
more than 60 percent of the 57 known cases. Preliminary findings in 
several of the whales have shown evidence of human interactions or 
infectious disease. These findings are not consistent across all of the 
whales examined, so more research is needed. As part of the UME 
investigation process, NOAA is assembling an independent team of 
scientists to coordinate with the Working Group on Marine Mammal 
Unusual Mortality Events to review the data collected, sample stranded 
whales, and determine the next steps for the investigation. More 
information is available at: www.fisheries.noaa.gov/national/marine-life-distress/2017-2018-minke-whale-unusual-mortality-event-along-atlantic-coast (accessed February 25, 2019).

Pilot Whale

    Both the long-finned and short-finned pilot whale could occur in 
the survey

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area. However, the long-finned pilot whale is more generally found 
farther north in deeper waters along the edge of the continental shelf 
(a depth of 330 to 3,300 feet (100 to 1,000 meters). While long-finned 
pilot whales have occasionally been observed stranded as far south as 
South Carolina, long-finned and short-finned pilot whales tend to 
overlap spatially along the mid-Atlantic shelf break between New Jersey 
and the southern flank of Georges Bank (Payne and Heinemann 1993; Rone 
and Pace 2012). The latitudinal ranges of the two species remain 
uncertain, although south of Cape Hatteras, most pilot whale sightings 
are expected to be short-finned pilot whales, while north of ~42[deg] N 
most pilot whale sightings are expected to be long-finned pilot whales 
(Hayes et al. 2018).

Bottlenose Dolphin

    The bottlenose dolphin occurs in oceans and peripheral seas at both 
tropical and temperate latitudes. In North America, bottlenose dolphins 
are found in surface waters with temperatures ranging from 10 to 
32[deg] C (50 to 90 [deg]F).
    There are two distinct bottlenose dolphin morphotypes: Coastal and 
offshore. The coastal morphotype resides in waters typically less than 
65.6 ft (20 m) deep, along the inner continental shelf (within 7.5 km 
(4.6 miles) of shore), around islands, and is continuously distributed 
south of Long Island, New York into the Gulf of Mexico. These coastal 
populations are subdivided into seven stocks based largely upon spatial 
distribution (Waring et al. 2016). Of these 7 coastal stocks, the 
Western North Atlantic Southern Migratory Coastal stock is common in 
the coastal continental shelf waters off the coast of Virginia and 
North Carolina (Waring et al. 2018). These animals often move into or 
reside in bays, estuaries, the lower reaches of rivers, and coastal 
waters. The Southern Migratory Coastal Stock is one of only two (the 
other being the Northern Migratory Coastal Stock) thought to make 
broad-scale, seasonal migrations in coastal waters of the western North 
Atlantic. The spatial distribution and migratory movements of the 
Southern Migratory Coastal Stock are poorly understood and have been 
defined based on movement data from satellite-tag telemetry and photo-
ID studies, and stable isotope studies. The distribution of this stock 
is best described by satellite tag-telemetry data which provided 
evidence for a stock of dolphins migrating seasonally along the coast 
between North Carolina and northern Florida (Garrison et al. 2017b). 
Tag-telemetry data collected from two dolphins tagged in November 2004 
just south of Cape Fear, North Carolina, suggested that, during 
October-December, this stock occupies waters of southern North Carolina 
(south of Cape Lookout) where it may overlap spatially with the 
Southern North Carolina Estuarine System (SNCES) Stock in coastal 
waters <=3 km from shore. Based on the satellite telemetry data, during 
January-March, the Southern Migratory Coastal Stock appears to move as 
far south as northern Florida. During April-June, the stock moves back 
north to North Carolina past the tagging site to Cape Hatteras, North 
Carolina (Garrison et al. 2017b). During the warm water months of July-
August, the stock is presumed to occupy coastal waters north of Cape 
Lookout, North Carolina, to Assateague, Virginia, including Chesapeake 
Bay.
    The Southern Migratory Coastal stock may also overlap to some 
degree with the western North Atlantic Offshore stock of common 
bottlenose dolphins. A combined genetic and logistic regression 
analysis that incorporated depth, latitude, and distance from shore was 
used to model the probability that a particular common bottlenose 
dolphin group seen in coastal waters was of the coastal versus offshore 
morphotype (Garrison et al. 2017a). North of Cape Hatteras during 
summer months, there is strong separation between the coastal and 
offshore morphotypes (Kenney 1990; Garrison et al. 2017a), and the 
coastal morphotype is nearly completely absent in waters >20 m depth. 
South of Cape Hatteras, the regression analysis indicated that the 
coastal morphotype is most common in waters <20 m deep, but occurs at 
lower densities over the continental shelf, in waters >20 m deep, where 
it overlaps to some degree with the offshore morphotype. For the 
purposes of defining stock boundaries, estimating abundance, and 
identifying bycaught samples, the offshore boundary of the Southern 
Migratory Coastal Stock is defined as the 20-m isobath north of Cape 
Hatteras and the 200-m isobath south of Cape Hatteras. In summary, this 
stock is best delimited in warm water months, when it overlaps least 
with other stocks, as common bottlenose dolphins of the coastal 
morphotype that occupy coastal waters from the shoreline to 200 m depth 
from Cape Lookout to Cape Hatteras, North Carolina, and coastal waters 
0-20 m in depth from Cape Hatteras to Assateague, Virginia, including 
Chesapeake Bay (Hayes et al. 2018).
    The biggest threat to the population is bycatch because they are 
frequently caught in fishing gear, gillnets, purse seines, and shrimp 
trawls (Waring et al., 2016). They have also been adversely impacted by 
pollution, habitat alteration, boat collisions, human disturbance, and 
are subject to bioaccumulation of toxins. Scientists have found a 
strong correlation between dolphins with elevated levels of PCBs and 
illness, indicating certain pollutants may weaken their immune system 
(ACSonline 2004).

Common Dolphin

    The short-beaked common dolphin is found world-wide 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 
2,000-m isobaths and over prominent underwater topography and east to 
the mid-Atlantic Ridge. Common dolphins have been noted to be 
associated with Gulf Stream features (CETAP 1982; Selzer and Payne 
1988; Waring et al., 1992). The species is less common south of Cape 
Hatteras, although schools have been reported as far south as the 
Georgia/South Carolina border (Hayes et al., 2018).

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., 2017). The Gulf of Maine stock is most common in continental shelf 
waters from Hudson Canyon to Georges Bank, and in the Gulf of Maine and 
lower Bay of Fundy. Sighting data indicate seasonal shifts in 
distribution (Northridge et al., 1997). During January to May, low 
numbers of white-sided dolphins are found from Georges Bank to Jeffreys 
Ledge (off New Hampshire), with even lower numbers south of Georges 
Bank, as documented by a few strandings collected on beaches of 
Virginia to South Carolina. From June through September, large numbers 
of white-sided dolphins are found from Georges Bank to the lower Bay of 
Fundy. From October to December, white-sided dolphins occur at 
intermediate densities from southern Georges Bank to southern Gulf of 
Maine. Infrequent Virginia and North Carolina observations appear to 
represent the southern extent of the species' range during the winter 
months (Hayes et al., 2018).

Atlantic Spotted Dolphin

    There are two species of spotted dolphin in the Atlantic Ocean, the 
Atlantic spotted dolphin (Stenella frontalis) and the pantropical 
spotted

[[Page 17391]]

dolphin (S. attenuata) (Perrin et al., 1987).
    The Atlantic spotted dolphin ranges from southern New England, 
south through the Gulf of Mexico and the Caribbean to Venezuela 
(Leatherwood et al., 1976; Perrin et al., 1994). The Atlantic spotted 
dolphin prefers tropical to warm temperate waters along the continental 
shelf 10 to 200 meters (33 to 650 feet) deep to slope waters greater 
than 500 meters (1640 feet) deep. They regularly occur in continental 
shelf waters south of Cape Hatteras and in continental shelf edge and 
continental slope waters north of this region (Payne et al., 1984; 
Mullin and Fulling 2003). Pantropical spotted dolphin sightings during 
surveys in the Atlantic have been concentrated in the slope waters 
north of Cape Hatteras while in waters south of Cape Hatteras sightings 
are recorded over the Blake Plateau and in deeper offshore waters of 
the mid-Atlantic. (NMFS 2014). Given that pantropical spotted dolphins 
are found in deeper slope waters, it is likely that only Atlantic 
spotted dolphins, preferring shallower waters, would be found in the 
survey area.

Risso's Dolphins

    Risso's dolphins are distributed worldwide in tropical and 
temperate seas and in the Northwest Atlantic occur from Florida to 
eastern Newfoundland. Off the northeastern U.S. coast, Risso's dolphins 
are distributed along the continental shelf edge from Cape Hatteras 
northward to Georges Bank during spring, summer, and autumn. In winter, 
the range is in the mid-Atlantic Bight and extends outward into oceanic 
waters. In general, the population occupies the mid-Atlantic 
continental shelf edge year round (Hayes et al., 2018).

Harbor Porpoise

    The harbor porpoise inhabits shallow, coastal waters, often found 
in bays, estuaries, and harbors. In the western Atlantic, they are 
found from Cape Hatteras north to Greenland. During summer (July to 
September), harbor porpoises are concentrated in the northern Gulf of 
Maine and southern Bay of Fundy region, generally in waters less than 
150 m deep with a few sightings in the upper Bay of Fundy and on 
Georges Bank. During fall (October-December) and spring (April-June), 
harbor porpoises are widely dispersed from New Jersey to Maine, with 
lower densities farther north and south. They are seen from the 
coastline to deep waters (>1800 m) although the majority of the 
population is found over the continental shelf. During winter (January 
to March), intermediate densities of harbor porpoises can be found in 
waters off New Jersey to North Carolina, and lower densities are found 
in waters off New York to New Brunswick, Canada. There does not appear 
to be a temporally coordinated migration or a specific migratory route 
to and from the Bay of Fundy region. However, during the fall, several 
satellite-tagged harbor porpoises did favor the waters around the 92-m 
isobaths (Hayes et al., 2018)

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 dB 
threshold from the normalized composite audiograms, with the exception 
for lower limits for low-frequency cetaceans where the lower bound was 
deemed to be biologically implausible and the lower bound from Southall 
et al., (2007) retained. The functional groups and the associated 
frequencies are indicated below (note that these frequency ranges 
correspond to the range for the composite group, with the entire range 
not necessarily reflecting the capabilities of every species within 
that group):
     Low-frequency cetaceans (mysticetes): generalized hearing 
is estimated to occur between approximately 7 Hz and 35 kHz;
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): Generalized hearing is estimated to occur 
between approximately 150 Hz and 160 kHz;
     High-frequency cetaceans (porpoises, river dolphins, and 
members of the genera Kogia and Cephalorhynchus; including two members 
of the genus Lagenorhynchus, on the basis of recent echolocation data 
and genetic data): Generalized hearing is estimated to occur between 
approximately 275 Hz and 160 kHz.
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Twelve marine mammal species, all cetaceans, have the reasonable 
potential to co-occur with the proposed survey activities. Please refer 
to Table 2. Of these cetacean species, 5 are classified as low-
frequency cetaceans (i.e., all mysticete species), 6 are classified as 
mid-frequency cetaceans (i.e., all delphinid species), and 1 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

[[Page 17392]]

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.

Acoustic Impacts

    HRG survey equipment use during the geophysical 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 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 a kilometer away. Acousticians often refer to the loudness 
of a sound at its source (typically referenced to one meter from the 
source) as 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) and assuming no other 
sources of propagation loss (see below). 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.

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). 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 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). Given the higher level 
of sound and/or longer durations of exposure necessary to cause PTS as 
compared with TTS, and the small zone within which sound levels would 
exceed criteria for onset of PTS, it is unlikely that PTS would occur 
during the proposed HRG surveys.

Temporary Threshold Shift

    TTS is the mildest form of hearing impairment that can occur during 
exposure to a loud sound (Kryter, 1985). While experiencing TTS, the 
hearing threshold rises and a sound must be stronger in order to be 
heard. At least in terrestrial mammals, TTS can last from minutes or 
hours to (in cases of strong TTS) days, can be limited to a particular 
frequency range, and can occur to varying degrees (i.e., a loss of a 
certain number of dBs of sensitivity). For sound exposures at or 
somewhat above the TTS threshold, hearing sensitivity in both 
terrestrial and marine mammals recovers rapidly after exposure to the 
noise ends.
    Marine mammal hearing plays a critical role in communication with 
conspecifics and in 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 takes place during a time when the animals is traveling 
through the open ocean, where ambient noise is lower and there are not 
as many competing sounds present. Alternatively, a larger amount and 
longer duration of TTS sustained during a time when communication is 
critical for successful mother/calf interactions could have more 
serious impacts if it were in the same frequency band as the necessary 
vocalizations and of a severity such that it impeded communication. The 
fact that animals exposed to levels and durations of sound that would 
be expected to result in this physiological response would also be 
expected to have behavioral responses of a comparatively more severe or 
sustained nature is also notable and potentially of more importance 
than the simple existence of a TTS.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale, harbor porpoise, and Yangtze finless 
porpoise) exposed to a limited number of sound sources (i.e., mostly 
tones and octave-band

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noise) in laboratory settings (e.g., Finneran et al., 2002 and 2010; 
Nachtigall et al., 2004; Lucke et al., 2009; Mooney et al., 2009; Popov 
et al., 2011; Finneran and Schlundt, 2010). In general, harbor 
porpoises (Lucke et al., 2009; Kastelein et al., 2012b) have a lower 
TTS onset than other measured cetacean species. However, even for these 
animals, which are better able to hear higher frequencies and may be 
more sensitive to higher frequencies, exposures on the order of 
approximately 170 dBRMS or higher for brief transient 
signals are likely required for even temporary (recoverable) changes in 
hearing sensitivity that would likely not be categorized as 
physiologically damaging (Lucke et al., 2009). 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 NMFS (2018), Southall et al. (2019), Finneran and Jenkins 
(2012), and Finneran (2015).
    Scientific literature highlights the inherent complexity of 
predicting TTS onset in marine mammals, as well as the importance of 
considering exposure duration when assessing potential impacts (Mooney 
et al., 2009a, 2009b; Kastak et al., 2007). Generally, with sound 
exposures of equal energy, quieter sounds (lower sound pressure level 
(SPL)) of longer duration were found to induce TTS onset more than 
louder sounds (higher SPL) of shorter duration (more similar to sub-
bottom profilers). For intermittent sounds, less threshold shift will 
occur than from a continuous exposure with the same energy (some 
recovery will occur between intermittent exposures) (Kryter et al., 
1966; Ward, 1997). For sound exposures at or somewhat above the TTS-
onset threshold, hearing sensitivity recovers rapidly after exposure to 
the sound ends; intermittent exposures recover faster in comparison 
with continuous exposures of the same duration (Finneran et al., 2010). 
NMFS considers TTS as Level B harassment that is mediated by 
physiological effects on the auditory system; however, NMFS does not 
consider TTS-onset to be the lowest level at which Level B harassment 
may occur.
    Marine mammals in the survey area during the HRG survey are 
unlikely to incur TTS hearing impairment due to the characteristics of 
the sound sources, which include low source levels (208 to 221 dB re 1 
[micro]Pa-m) 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 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 be more likely to 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 temporary threshold shift 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 
discountable, 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.

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 (Thompson, 
1965; 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 sub-bottom profiler signals given the directionality of the 
signal and the brief period when an individual mammal is likely to be 
within its beam.

[[Page 17394]]

Non-Auditory Physical Effects (Stress)

    Classic stress responses begin when an animal's central nervous 
system 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 or the hypothalamus-pituitary-interrenal axis in fish 
and some reptiles). 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. In a conceptual model developed by the Population Consequences 
of Acoustic Disturbance (PCAD) working group, serum hormones were 
identified as possible indicators of behavioral effects that are 
translated into altered rates of reproduction and mortality (NRC 2005).
    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 effect of 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. 
NMFS does not expect that the generally short-term, intermittent, and 
transitory HRG surveys would create conditions of long-term, continuous 
noise and chronic acoustic exposure

[[Page 17395]]

leading to long-term physiological stress responses in marine mammals.

Behavioral Disturbance

    Behavioral responses to sound are highly variable and context-
specific. An animal's perception of and response to (in both nature and 
magnitude) an acoustic event can be influenced by prior experience, 
perceived proximity, bearing of the sound, familiarity of the sound, 
etc. (Southall et al., 2007; DeRuiter et al., 2013a and 2013b). If a 
marine mammal does react briefly to an underwater sound by changing its 
behavior or moving a small distance, the impacts of the change are 
unlikely to be significant to the individual, let alone the stock or 
population. However, if a sound source displaces marine mammals from an 
important feeding or breeding area for a prolonged period, impacts on 
individuals and populations could be significant (e.g., Lusseau and 
Bejder, 2007; Weilgart, 2007).
    Southall et al. (2007) reports the results of the efforts of a 
panel of experts in acoustic research from behavioral, physiological, 
and physical disciplines that convened and reviewed the available 
literature on marine mammal hearing and physiological and behavioral 
responses to human-made sound with the goal of proposing exposure 
criteria for certain effects. This peer-reviewed compilation of 
literature is very valuable, though Southall et al. (2007) note that 
not all data are equal, some have poor statistical power, insufficient 
controls, and/or limited information on received levels, background 
noise, and other potentially important contextual variables--such data 
were reviewed and sometimes used for qualitative illustration but were 
not included in the quantitative analysis for the criteria 
recommendations. All of the studies considered, however, contain an 
estimate of the received sound level when the animal exhibited the 
indicated response.
    Studies that address responses of low-frequency cetaceans to sounds 
include data gathered in the field and related to several types of 
sound sources, including: vessel noise, drilling and machinery 
playback, low-frequency M-sequences (sine wave with multiple phase 
reversals) playback, tactical low-frequency active sonar playback, 
drill ships, and non-pulse playbacks. These studies generally indicate 
no (or very limited) responses to received levels in the 90 to 120 dB 
re: 1[micro]Pa range and an increasing likelihood of avoidance and 
other behavioral effects in the 120 to 160 dB range. As mentioned 
earlier, though, contextual variables play a very important role in the 
reported responses and the severity of effects do not increase linearly 
with received levels. Also, few of the laboratory or field datasets had 
common conditions, behavioral contexts, or sound sources, so it is not 
surprising that responses differ.
    The studies that address responses of mid-frequency cetaceans to 
sounds include data gathered both in the field and the laboratory and 
related to several different sound sources, including: pingers, 
drilling playbacks, ship and ice-breaking noise, vessel noise, acoustic 
harassment devices (AHDs), acoustic deterrent devices (ADDs), mid-
frequency active sonar, and non-pulse bands and tones. Southall et al. 
(2007) were unable to come to a clear conclusion regarding the results 
of these studies. In some cases animals in the field showed significant 
responses to received levels between 90 and 120 dB, while in other 
cases these responses were not seen in the 120 to 150 dB range. The 
disparity in results was likely due to contextual variation and the 
differences between the results in the field and laboratory data 
(animals typically responded at lower levels in the field). The studies 
that address the responses of mid-frequency cetaceans to impulse sounds 
include data gathered both in the field and the laboratory and related 
to several different sound sources, including: small explosives, airgun 
arrays, pulse sequences, and natural and artificial pulses. The data 
show no clear indication of increasing probability and severity of 
response with increasing received level. Behavioral responses seem to 
vary depending on species and stimuli.
    The studies that address responses of high-frequency cetaceans to 
sounds include data gathered both in the field and the laboratory and 
related to several different sound sources, including: Pingers, AHDs, 
and various laboratory non-pulse sounds. All of these data were 
collected from harbor porpoises.
    Marine mammals are likely to avoid the HRG survey activity, 
especially harbor porpoises. However, because the sub-bottom profilers 
and other HRG survey equipment operate from a moving vessel, and the 
assumed behavioral harassment distance is small (see Estimated Take), 
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, therefore 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 Avangrid's use of HRG survey equipment, on the basis of a 2008 
mass stranding of approximately one hundred 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,

[[Page 17396]]

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 kilometers. However, other studies have shown that 
marine mammals at distances more than a few kilometers 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 and toothed whales 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). Due to the relatively high 
vessel traffic in the survey area it is possible that marine mammals 
are habituated to noise from project vessels in the area.

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 knots). 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 vessels and are likely already 
habituated to the presence of numerous vessels in the area. Further, 
Avangrid will implement measures (e.g., vessel speed restrictions and 
separation distances; see Proposed Mitigation Measures) to reduce the 
risk of a vessel strike to marine mammal species in the survey area.

Effects on 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 with the exception of a migratory BIA for right whales which was 
described previously. There is also no designated critical habitat for 
any ESA-listed marine mammals. NMFS' regulations at 50 CFR 224.105 
designated the nearshore waters of the Mid-Atlantic Bight as the Mid-
Atlantic SMA for right whales in 2008. Mandatory vessel speed 
restrictions 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.
    We are not aware of any available literature on impacts to marine 
mammal prey species from HRG survey equipment. However, because the HRG 
survey equipment introduces noise to the marine environment, there is 
the potential for avoidance of the area around the HRG survey 
activities by marine mammal prey species. Any avoidance of the area on 
the part of marine mammal prey species 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, section 3(18) of the MMPA defines ``harassment'' as: Any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed or incur some 
degree of permanent hearing impairment; (2) the area or volume of water 
that will be ensonified above these levels in a day; (3) the density or 
occurrence of marine mammals within these ensonified areas; and, (4) 
and the number of days of activities. We note that while these basic 
factors can contribute to a calculation to provide an initial 
prediction of takes, additional information that can qualitatively 
inform take estimates is also sometimes available (e.g., previous 
monitoring

[[Page 17397]]

results or average group size). Below, we describe the factors 
considered here in more detail and present the proposed take estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B harassment) or to incur PTS 
of some degree (equated to Level A harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive 
(e.g., seismic airguns) or intermittent (e.g., scientific sonar) 
sources. Avangrid's proposed activity includes the use of impulsive 
and/or intermittent sources (HRG equipment) and, therefore, the 160 dB 
re 1 [mu]Pa (rms) is applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (NMFS, 2018) identifies dual criteria to 
assess auditory injury (Level A harassment) to five different marine 
mammal groups (based on hearing sensitivity) as a result of exposure to 
noise from two different types of sources (impulsive or non-impulsive). 
Avangrid's proposed activity includes the use of impulsive sources 
(medium penetration sub-bottom profiler) and non-impulsive sources 
(shallow penetration sub-bottom profiler).
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
----------------------------------------------------------------------------------------------------------------
             Hearing group                        Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (FF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 201 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to reflect American National
  Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
  frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
  being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
  designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
  that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
  exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
  is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
    Previously we explained that auditory injury of marine mammals is 
unlikely given the higher level of sound and/or longer durations of 
exposure necessary to cause PTS and the small zone within which sound 
levels would exceed criteria for onset of PTS. The information provided 
in Tables 4 and 5 support this position and demonstrate that the 
proposed mitigation measures are based on a highly conservative 
evaluation of potential acoustic impacts.
    When the NMFS Technical Guidance was first published in 2016, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of Level A harassment take. However, these tools offer the 
best way to predict appropriate isopleths when more sophisticated 3D 
modeling methods are not available. NMFS continues to develop ways to 
quantitatively refine these tools, and will qualitatively address the 
output where appropriate. For mobile sources, including the HRG survey 
equipment, 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. Note however, that 
use of the spreadsheet is generally not appropriate for use in 
assessing potential for Level A harassment for very highly directional 
sources, such as the Innomar SES-2000, for reasons explained below. 
Inputs used in the User Spreadsheet and the resulting isopleths are 
reported below.

[[Page 17398]]



              Table 4--User Spreadsheet Input Parameters Used for Calculating Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                                USBL             Shallow             Medium
                                                        -------------------  penetration SBP    penetration SBP
                                                                           -------------------------------------
                  Spreadsheet tab used                   D: Mobile source:  D: Mobile source:  F: Mobile source:
                                                           Non-impulsive,     Non-impulsive,       Impulsive,
                                                            intermittent       intermittent       intermittent
----------------------------------------------------------------------------------------------------------------
Source Level (dB)......................................        188 RMS SPL        179 RMS SPL        206 RMS SPL
Weighting Factor Adjustment (kHz)......................               26.5                2.6                1.4
Source Velocity (m/s)..................................              2.058              2.058              2.058
Pulse Duration (seconds)...............................              0.016             0.0658              0.008
1/Repetition rate- (seconds)...........................               0.33               0.25               0.25
Source Level (PK SPL)..................................  .................  .................                215
Propagation (xLogR)....................................                 20                 20                 20
----------------------------------------------------------------------------------------------------------------

    Note that the Innomar SES-2000 is a specialized type of HRG sub-
bottom profiler that uses the principle of ``parametric'' or 
``nonlinear'' acoustics to generate short narrow-beam sound pulses. As 
no field data currently exists for the Innomar sub-bottom profiler 
acoustic modeling was completed using a version of the U.S. Naval 
Research Laboratory's Range-dependent Acoustic Model (RAM) and BELLHOP 
Gaussian beam ray-trace propagation model (Porter and Liu 1994). 
Calculations of the ensonified area are conservative due to the 
directionality of the sound sources. Due to the short sound pulses and 
the highly directional sound pulse transmission (1[deg] beamwidth) of 
parametric sub-bottom profilers, the volume of area affected is much 
lower than using conventional (linear) acoustics devices such as 
sparker and chirp systems. Level A harassment zones of less than 5 
meters (Table 5) for HF cetaceans were calculated for this HRG 
equipment in the proposed survey area while Level B harassment 
isopleths were found to range from 120 to 135 meters (Table 6).

                Table 5--Maximum Distances to Level A Harassment Thresholds by Equipment Category
----------------------------------------------------------------------------------------------------------------
                                                                                                      Lateral
   Representative HRG survey equipment        Marine mammal group              PTS onset           distance (m)
----------------------------------------------------------------------------------------------------------------
                                          USBL/GAPS Positioning Systems
----------------------------------------------------------------------------------------------------------------
Sonardyne Ranger 2 USBL HPT 5/7000......  LF cetaceans..............  199 dB SELcum.............
                                          MF cetaceans..............  198 dB SELcum.............
                                          HF cetaceans..............  173 dB SELcum.............               3
----------------------------------------------------------------------------------------------------------------
                                           Shallow Sub-bottom Profiler
----------------------------------------------------------------------------------------------------------------
Edgetech 512i...........................  LF cetaceans..............  199 dB SELcum.............
                                          MF cetaceans..............  198 dB SELcum.............
                                          HF cetaceans..............  173 dB SELcum.............
----------------------------------------------------------------------------------------------------------------
                                     Shallow Parametric Sub-bottom Profiler
----------------------------------------------------------------------------------------------------------------
Innomar SES-2000 Standard Parametric Sub- LF cetaceans..............  199 dB SELcum.............             N/A
 bottom Profiler.
                                          MF cetaceans..............  198 dB SELcum.............
                                          HF cetaceans..............  173 dB SELcum.............              <5
----------------------------------------------------------------------------------------------------------------
                                     Medium Penetration Sub-bottom Profiler
----------------------------------------------------------------------------------------------------------------
SIG ELC 820 Sparker.....................  LF cetaceans..............  219 dBpeak, 183 dB SELcum.          --, 10
                                          MF cetaceans..............  230 dBpeak, 185 dB SELcum.           --,--
                                          HF cetaceans..............  202 dBpeak, 155 dB SELcum.            5, 4
----------------------------------------------------------------------------------------------------------------
Notes:
The peak SPL criterion is un-weighted (i.e., flat weighted), whereas the cumulative SEL criterion is weighted
  for the given marine mammal functional hearing group.
The calculated sound levels and results are based on NMFS Technical Guidance's companion User Spreadsheet except
  as indicated.
-- indicates that no injury was predicted for the given HRG equipment noise profile.
N/A indicates not applicable as the HRG sound source operates outside the effective marine mammal hearing range

    Distances to Level B harassment noise thresholds were calculated 
using the conservative practical spreading model (transmission loss 
(TL) equation: TL = 15log10r), with the exception of the 
Innomar SES-2000 described previously. The Sig ELC 820 Sparker was 
calculated to have the largest Level B harassment isopleth of 200 m 
(656.2 ft). To account for some of the potential variation of operating 
conditions, the maximum distance of 200 m to the harassment thresholds 
is used to determine estimated exposure. The 200 m distance to the 
medium penetration sub-bottom profiler represents the largest distance 
and is likely a very conservative estimate based on sound

[[Page 17399]]

source field verification assessments of similar sparker electrode 
equipment.
    The 200 m distance to the medium penetration sub-bottom profiler 
represents the largest distance and is likely a very conservative 
estimate based on sound source field verification assessments of 
similar sparker electrode equipment.

           Table 6--Distances to Level B Harassment Thresholds
                               [160 dBRMS]
------------------------------------------------------------------------
                                                         Marine mammal
                                                            level B
                   Survey equipment                      harassment 160
                                                           dBRMS re 1
                                                         [micro]Pa (m)
------------------------------------------------------------------------
                                  USBL
------------------------------------------------------------------------
Sonardyne Ranger 2 USBL..............................                 25
------------------------------------------------------------------------
                 Shallow penetration sub-bottom profiler
------------------------------------------------------------------------
EdgeTech 512i........................................                 10
Innomar parametric SES-2000 Standard.................            120-135
------------------------------------------------------------------------
                 Medium penetration sub-bottom profiler
------------------------------------------------------------------------
SIG ELC 820 Sparker..................................                200
------------------------------------------------------------------------

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 data used as the basis for estimating cetacean 
density (``D'') for the survey area are sightings per unit effort 
(SPUE) derived by Duke University (Roberts et al. 2016a), updated with 
new modeling results (Roberts et al. 2016b; 2017; 2018). SPUE (or, the 
relative abundance of species) is derived by using a measure of survey 
effort and number of individual cetaceans sighted. SPUE allows for 
comparison between discrete units of time (i.e. seasons) and space 
within a project area (Shoop and Kenney, 1992). The Duke University 
(Roberts et al. 2016) cetacean density data represent models derived 
from aggregating line-transect surveys conducted over 23 years by five 
institutions (NOAA NMFS Northeast Fisheries Science Center, New Jersey 
Department of Environmental Protection, NOAA NMFS Southeast Fisheries 
Science Center, University of North Carolina Wilmington, and Virginia 
Aquarium & Marine Science Center). Model versions discussed in Roberts 
et al. (2016a) are freely available online at the Ocean Biogeographic 
Information System Spatial Ecological Analysis of Megavertebrate 
Populations (OBISSEAMAP) repository. Monthly mean density values within 
the survey area were averaged by season (Winter (December, January, 
February), Spring (March, April, May), Summer (June, July, August), 
Fall (September, October, November)) to provide seasonal density 
estimates for those taxa for which monthly model results are available. 
The highest seasonal density estimates during the duration of the 
proposed survey were used to estimate take (i.e., summer or fall). 
(2016b; 2017; 2018).

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 the estimated survey vessel trackline distance 
traveled per day.
    The survey activities that have the potential to cause Level B 
harassment (160 dBRMS re 1 [micro]Pa) are listed in Table 6. 
Based on the results of this assessment, the furthest distance to the 
Level B harassment criteria is 200 m from the use of the SIG ELC 820 
Sparker. As a conservative measure to account for some of the potential 
variation of operating conditions, the maximum distance of 200 m to the 
Level B harassment isopleth for the SIG ELC 820 Sparker is used to 
determine estimated exposure for the entire HRG survey.
    The estimated distance of the daily vessel trackline was determined 
using the estimated average speed of the vessel (4 knots) and the 24-
hour operational period. Using the maximum distance to the Level B 
harassment threshold of 200 m (656 ft) and estimated daily vessel track 
of approximately 177.8 km (110.5 mi), estimates of take by survey 
equipment has been based on an ensonified area around the survey 
equipment of 71.2 km\2\ (27.5 mi\2\) per day over a projected survey 
period for each survey segment as shown in Table 7.

                         Table 7--Survey Segment Distances and Level B Harassment Zones
----------------------------------------------------------------------------------------------------------------
                                                                                                    Calculated
                                                     Number of       Estimated       Estimated        level B
                 Survey segment                    active survey   distances per    total line      harassment
                                                       days          day (km)        distance      zone per day
                                                                                                      (km\2\)
----------------------------------------------------------------------------------------------------------------
Lease Area......................................              29           177.8           5,156            71.2
Cable Route Corridor............................               8           177.8           1,422            71.2
----------------------------------------------------------------------------------------------------------------

    The parameters in Table 7 were used to estimate the potential take 
by incidental harassment for each segment of the HRG survey. Density 
data from Roberts et al. (2016b; 2017; 2018) were mapped within the 
boundary of the survey area for each segment (Figure 1 in application) 
using geographic information systems. For both survey segments, species 
densities, as reported by Roberts et al. (2016) within the maximum 
survey area, were averaged by season (spring and summer) based on the 
proposed HRG survey schedule (commencing no earlier than June 1, 2019). 
Potential take calculations were then based on the maximum average 
seasonal species density (between spring and summer) within the maximum 
survey area, given the survey start date and duration. Results of the 
take calculations by survey segment are provided in Table 8.

[[Page 17400]]



                                         Table 8--Marine Mammal Density and Estimated Take by Level B Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Lease area                 Cable Corridor Route                   Totals
                                                         -----------------------------------------------------------------------------------------------
                                                              Maximum                         Maximum
                                                              average                         average
                         Species                             seasonal       Calculated       seasonal       Calculated      Total take      Percent of
                                                            density \1\    Take (number)    density \1\    Take (number)   authorization    population
                                                           (No. /100 km                    (No. /100 km                      (number)
                                                               \2\)                            \2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale..............................           0.051           1.063           0.051           0.288             3 0
Humpback whale..........................................           0.466           9.631           0.102           0.581              10            1.11
Fin whale...............................................           0.328           6.773           0.128           0.729             3 0
Sei whale...............................................           0.020           0.406           0.003           0.018               0
Minke whale.............................................           0.757          15.643           0.171          0.9722              17            0.65
Pilot whale.............................................           0.100           2.073           0.034           0.195          4 5 10           <0.01
Harbor porpoise.........................................           1.252          25.874           0.690           3.931              30           <0.01
Bottlenose dolphin (WNA southern migratory coastal) \2\.           0.000           0.000          49.102         104.944             105             2.8
Bottlenose dolphin (offshore) \2\.......................           6.409         132.413          49.102         174.906             307           <0.01
Short beaked common dolphin.............................           5.241         108.275           2.144          12.221             120            0.17
Atlantic white-sided dolphin............................           2.482          51.288           0.320           1.826              53            0.11
Atlantic spotted dolphin................................           8.895         183.772           3.493          19.910             204            0.46
Risso's dolphin.........................................           0.074           1.525           0.074           0.421          \4\ 40            0.21
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Density values from Duke University (Roberts et al. 2016b; 2017; 2018).
\2\ Estimates split based on bottlenose dolphin stock preferred water depths (Reeves et al. 2002; Waring et al. 2016).
\3\ No take proposed for authorization, as discussed below.
\4\ Adjusted for group size.
\5\ For short-finned and long-finned pilot whales, percentage of stock taken is <0.01percent both species if all 10 takes are allocated separately to
  each species.

    Since the calculated take value for pilot whales (2) is less than 
the mean group size (9.4), NMFS assumed that take of at least one group 
of pilot whales could occur (Silva et al, 2014). For bottlenose dolphin 
densities, Roberts et al. (2016b; 2017; 2018) does not differentiate by 
individual stock. Given the southern coastal migratory stock's 
propensity to be found in waters shallower than the 20 m depth isobath 
north of Cape Hatteras (Reeves et al. 2002; Waring et al. 2016), the 
Export Cable Corridor segment was roughly divided along the 20 m depth 
isobath. The Lease Area is located within depths exceeding 20 m, where 
the southern coastal migratory stock would be unlikely to occur. 
Roughly 40 percent of the Export Cable Corridor is 20 m or less in 
depth. Given the Export Cable Corridor area is estimated to take 8 days 
to complete survey activity, 3 days have been estimated for depths 
shallower than 20 m. Therefore, to account for the potential for mixed 
stocks within the Export Cable Corridor, 3 days has been applied to the 
take estimation equation for the southern coastal migratory stock and 
the remaining applied to the offshore stock (5 days). The offshore 
stock is the only stock of bottlenose dolphins that may occur in the 
lease area; therefore bottlenose dolphin densities within the Lease 
Area have been considered part of the offshore stock only for purposes 
of take estimation.
    For Risso's dolphins, NMFS adjusted the calculated take number to 
account for group size. These 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). NMFS conservatively assumed that a 
group of 40 or several smaller groups not exceeding a total of 40 takes 
by Level B harassment.
    The three ESA-listed large whales that could potentially be present 
in the survey area occur at very low densities, and the calculated 
numbers of potential acoustic exposures above the 160-dB threshold are 
small, i.e., one right whale exposure, zero sei whale exposures, and 
eight fin whale exposures. In addition, Avangrid proposed a 500 m 
(1,640 ft) exclusion zone for the right whale and NMFS recommended a 
200 m (656 ft) exclusion zone for sei and fin whales. Both of these 
measures are incorporated into the proposed IHA (see ``Proposed 
Mitigation''). These exclusion zones exceed (in the case of right 
whales) or equal (in the case of sei and fin whales) the distance to 
the conservatively calculated Level B harassment isopleth. Given the 
low likelihood of exposure in context of the proposed mitigation 
requirements (with relatively high detection probabilities for large 
whales at these distances during good visibility), we believe that 
there is not a reasonably anticipated potential for the specified 
activity to cause the disruption of behavioral patterns for these 
species. Therefore, we do not propose to authorize take by Level B 
harassment for these species.

Proposed Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting such 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or

[[Page 17401]]

stocks, and their habitat. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the likelihood that the measure will be effective if 
implemented (probability of accomplishing the mitigating result if 
implemented as planned) the likelihood of effective implementation 
(probability implemented as planned) and;
    (2) the practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    Avangrid's application included a list of proposed mitigation 
measures during site characterization surveys utilizing HRG survey 
equipment. NMFS proposes the additional measure of establishing an 
exclusion zone of 200 m for sei and fin whales. The mitigation measures 
outlined in this section are based on protocols and procedures that 
have been successfully implemented and previously approved by NMFS 
(DONG Energy, 2016, ESS, 2013; Dominion, 2013 and 2014).

Visual Monitoring

    Visual monitoring of designated exclusion and Level B harassment 
zones will ensure that (1) Any take of ESA-listed species would be 
limited; (2) exposure to underwater noise does not result in injury 
(Level A harassment), and (3) the number of instances of take does not 
exceed the authorized amounts. PSOs will coordinate to ensure 360[deg] 
visual coverage around the vessel and conduct visual observations while 
free from distractions and in a consistent, systematic, and diligent 
manner. Visual PSOs shall immediately communicate all observations of 
marine mammals to the on-duty acoustic PSO(s), including any 
determination by the PSO regarding species identification, distance, 
and bearing and the degree of confidence in the determination. Any 
observations of marine mammal species by crew members aboard any vessel 
associated with the survey shall be relayed to the PSO team.
    PSOs will establish and monitor applicable exclusion zones. During 
use of HRG acoustic sources (i.e., anytime the acoustic source is 
active), occurrences of marine mammal species approaching the relevant 
exclusion zone will be communicated to the operator to prepare for the 
potential shutdown of the acoustic source. Exclusion zones are defined, 
depending on the species and context, below:
     500 m (1,640 ft) exclusion zone for North Atlantic right 
whales;
     200 m (656 ft) exclusion zone for sei and fin whales; and
     100 m (328 ft) exclusion zone for other large cetaceans 
(i.e., humpback whale, minke whale, pilot whale, Risso's dolphin).
    The Level B harassment zone represents the zone within which marine 
mammals would be considered taken by Level B harassment and will 
encompass a distance of 200 m (656 ft) from survey equipment for all 
marine mammal species.

Pre-Clearance

    Avangrid will implement a 30-minute clearance period of the 
exclusion zones. This will help ensure marine mammals are not in the 
exclusion zones prior to startup of HRG equipment. During this period 
the exclusion zones will be monitored by the PSOs, using the 
appropriate visual technology for a 30-minute period. The intent of 
pre-clearance observation is to ensure no marine mammal species are 
observed within the exclusion zones prior to the beginning of operation 
of HRG equipment. A PSO conducting pre-clearance observations must be 
notified immediately prior to initiating start of HRG equipment and the 
operator must receive confirmation from the PSO to proceed.
    Activation of HRG equipment may not be initiated if any marine 
mammal is observed within the applicable exclusion zones as described 
above. If a marine mammal is observed within the applicable exclusion 
zone during the 30 minute pre-clearance period, activation of HRG 
equipment may not begin until the animal(s) has been observed exiting 
the zones or until an additional time period has elapsed with no 
further sightings (15 minutes for small delphinoid cetaceans and 30 
minutes for all other species). Activation of HRG equipment may occur 
at times of poor visibility, including nighttime, if continuous visual 
observation and has occurred with no detections of marine mammals in 
the 30 minutes prior to beginning of start-up.

Shutdown Procedures

    An immediate shutdown of the HRG survey equipment will be required 
if a marine mammal is sighted at or within its respective exclusion 
zone to minimize or avoid behavioral impacts to ESA-listed species. The 
vessel operator must comply immediately with any call for shutdown by 
the lead PSO. The operator must establish and maintain clear lines of 
communication directly between PSOs on duty and crew controlling the 
acoustic source to ensure that shutdown commands are conveyed swiftly 
while allowing PSOs to maintain watch. When shutdown is called for by a 
PSO, the acoustic source must be immediately deactivated and any 
dispute resolved only following deactivation.
    Should there be any uncertainty regarding identification of a 
marine mammal species (i.e., whether the observed marine mammal(s) 
belongs to one of the delphinid genera for which shutdown is waived or 
one of the species with a larger exclusion zone), visual PSOs may use 
best professional judgment in making the decision to call for a 
shutdown. 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 the 200 m Level B harassment zone, shutdown must occur.
    Subsequent restart of the survey equipment can be initiated if the 
animal has been observed exiting its respective exclusion zone within 
30 minutes of the shutdown or an additional time period has elapsed 
with no further sighting (i.e., 15 minutes for small odontocetes and 30 
minutes for all other species).
    If the acoustic source is shut down for reasons other than 
mitigation (e.g., mechanical difficulty) for less than 30 minutes, it 
may be activated again without pre-clearance protocols, if PSOs have 
maintained constant observation and no detections of any marine mammal 
have occurred within the respective exclusion zones.

Vessel Strike Avoidance

    In order to avoid striking animals, vessel operators and crews must 
maintain a vigilant watch for all marine mammal species and slow down, 
stop their vessel, or alter course, as appropriate and regardless of 
vessel size. A visual observer aboard the vessel must monitor a vessel 
strike avoidance zone around the vessel (distances stated below). 
Visual observers monitoring the vessel strike avoidance zone may be 
third-party observers (i.e., PSOs) or crew members, but crew members 
responsible for these duties must be provided sufficient training to 
distinguish marine mammal species from other phenomena and broadly to 
identify a marine mammal as a right whale, other whale (defined in this 
context as sperm whales or baleen whales other than right whales), or 
other marine mammal. Vessel strike avoidance measures will include the 
following:

[[Page 17402]]

     All vessels (e.g., source vessels, chase vessels, supply 
vessels), regardless of size, must observe a 10-knot speed restriction 
in specific areas designated by NMFS for the protection of North 
Atlantic right whales from vessel strikes: Any Dynamic Management Areas 
(DMA) when in effect, and the Mid-Atlantic Seasonal Management Areas 
(SMA) (from November 1 through April 30). See 50 CFR 224.105 and 
www.fisheries.noaa.gov/national/endangered-species-conservation/reducing-ship-strikes-north-atlantic-right-whales for specific detail 
regarding these areas.
     Vessel speeds must also be reduced to 10 knots or less, 
regardless of location, when mother/calf pairs, pods, or large 
assemblages of cetaceans are observed near a vessel;
     All vessels must maintain a minimum separation distance of 
500 m from right whales. If a whale is observed but cannot be confirmed 
as a species other than a right whale, the vessel operator must assume 
that it is a right whale and take appropriate action;
     All vessels must maintain a minimum separation distance of 
100 m from all other baleen whales and sperm whales;
     All vessels must, to the maximum extent practicable, 
attempt to maintain a minimum separation distance of 50 m from all 
other marine mammals, with an understanding that at times this may not 
be possible (e.g., for animals that approach the vessel).
     When marine mammals are sighted while a vessel is 
underway, the vessel shall take action as necessary to avoid violating 
the relevant separation distance, e.g., attempt to remain parallel to 
the animal's course, avoid excessive speed or abrupt changes in 
direction until the animal has left the area. If marine mammals are 
sighted within the relevant separation distance, the vessel must reduce 
speed and shift the engine to neutral, not engaging the engines until 
animals are clear of the area. This does not apply to any vessel towing 
gear or any vessel that is navigationally constrained.
     These requirements do not apply in any case where 
compliance would create an imminent and serious threat to a person or 
vessel or to the extent that a vessel is restricted in its ability to 
maneuver and, because of the restriction, cannot comply.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

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

Proposed Monitoring and Reporting Measures

Visual Monitoring

    Visual monitoring shall be conducted by NMFS-approved PSOs. PSO 
resumes shall be provided to NMFS for approval prior to commencement of 
the survey. Avangrid must use independent, dedicated, trained PSOs, 
meaning that the PSOs must be employed by a third-party observer 
provider, must have no tasks other than to conduct observational 
effort, collect data, and communicate with and instruct relevant vessel 
crew with regard to the presence of marine mammals and mitigation 
requirements (including brief alerts regarding maritime hazards).
    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 the PSO shall 
occur when alerted of a marine mammal presence. An observer team 
comprising a minimum of four NMFS-approved PSOs, operating in shifts, 
will be stationed aboard the survey vessel. PSO's 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 1 on 
and 3 off, and during nighttime operations PSOs will work in pairs.
    PSOs must have all equipment (including backup equipment) needed to 
adequately perform necessary tasks, including accurate determination of 
distance and bearing to observed marine mammals. PSOs will be equipped 
with binoculars and have the ability to estimate distances to marine 
mammals located in proximity to their established zones 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. Cameras of appropriate quality will 
be used for photographs and video to record sightings and verify 
species identification. Each PSO must have a camera and backup cameras 
should be available. During night operations, night-vision equipment 
(night-vision goggles with thermal clip-ons) and infrared technology 
will be used. Position data will be recorded using hand-held or vessel 
global positioning system (GPS) units for each sighting. Radios for 
each PSO are required in order to communicate among vessel crew and 
PSOs. PSO must also have compasses and any other tools necessary to 
perform other PSO tasks.

[[Page 17403]]

    PSOs shall be responsible for visually monitoring and identifying 
marine mammals approaching or entering the established monitoring zones 
as well as beyond the monitoring zones to the maximum extent possible. 
PSOs will record animals both within and beyond the monitoring zones 
during survey activities.
    Data on all PSO observations must be recorded based on standard PSO 
collection requirements. PSOs must use standardized data forms, whether 
hard copy or electronic. This shall include the following:
     Vessel names (source vessel and other vessels associated 
with survey), vessel size and type, maximum speed capability of vessel, 
port of origin, and call signs;
     PSO names and affiliations;
     Dates of departures and returns to port with port name;
     Date and participants of PSO briefings;
     Dates and times (Greenwich Mean Time) of survey effort and 
times corresponding with PSO effort;
     Vessel location (latitude/longitude) when survey effort 
begins and ends; vessel location at beginning and end of visual PSO 
duty shifts;
     Vessel heading and speed at beginning and end of visual 
PSO duty shifts and upon any line change;
     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;
     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);
     Survey activity information, such as acoustic source power 
output while in operation, and any other notes of significance (i.e., 
pre-ramp-up survey, ramp-up, shutdown, testing, ramp-up completion, end 
of operations, etc.);
     If a marine mammal is sighted, the following information 
should be reported:
    (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.

Proposed Reporting Measures

    Within 90 days after completion of survey activities, a final 
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. All raw 
observational data shall be made available to NMFS. The draft report 
must be accompanied by a certification from the lead PSO as to the 
accuracy of the report, and the lead PSO may submit directly to NMFS a 
statement concerning implementation and effectiveness of the required 
mitigation and monitoring. Any recommendations made by NMFS must be 
addressed in the final report prior to acceptance by NMFS. A final 
report must be submitted within 30 days following resolution of any 
comments on the draft report.

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), Avangrid 
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 Southeast Regional Stranding 
Coordinator. The report would include the following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Name and type of vessel involved;
     Vessel's speed during and leading up to the incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     Water depth;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     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 Avangrid to minimize 
reoccurrence of such an event in the future. Avangrid would not resume 
activities until notified by NMFS.
    In the event that Avangrid 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), Avangrid would immediately report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources and the NMFS Southeast Regional 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 Avangrid to 
determine if modifications in the activities are appropriate.
    In the event that Avangrid 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), Avangrid would report the incident to the Chief of 
the Permits and Conservation Division, Office of

[[Page 17404]]

Protected Resources, and the NMFS Southeast Regional Stranding 
Coordinator, within 24 hours of the discovery. Avangrid would provide 
photographs or video footage (if available) or other documentation of 
the stranded animal sighting to NMFS. Avangrid may continue its 
operations under such a case.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    To avoid repetition, this introductory discussion of our analyses 
applies to all the species listed in Table 8, given that many of the 
anticipated effects of this project on different marine mammal stocks 
are expected to be relatively similar in nature. Where there are 
meaningful differences between species or stocks, or groups of species, 
in anticipated individual responses to activities, impact of expected 
take on the population due to differences in population status, or 
impacts on habitat, they are described independently in the analysis 
below.
    As discussed in the ``Potential Effects of the Specified Activity 
on Marine Mammals and Their Habitat'' section, PTS, masking, non-
auditory physical effects, and vessel strike are not expected to occur. 
Marine mammal habitat may be impacted by elevated sound levels but 
these impacts would be short term. Feeding behavior is not likely to be 
significantly impacted. Prey species are mobile, and are broadly 
distributed throughout the survey 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 availability of 
similar habitat and resources 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. Additionally, there are no feeding areas 
or mating grounds known to be biologically important to marine mammals 
within the proposed project area with the exception of a migratory BIA 
for North Atlantic right whales described below.

Biologically Important Areas (BIA)

    The proposed survey area includes a biologically important 
migratory area for North Atlantic right whales (effective March-April 
and November-December) that extends from Massachusetts to Florida 
(LaBrecque, et al., 2015). As previously noted, no take of North 
Atlantic right whales has been proposed, and HRG survey operations will 
be required to shut down at 500 m to further minimize any potential 
effects to this species. The fact that the spatial acoustic footprint 
of the proposed survey is very small relative to the spatial extent of 
the available migratory habitat leads us to expect that right whale 
migration will not be impacted by the proposed survey.

Unusual Mortality Events (UME)

    A UME is defined under the MMPA as a stranding that is unexpected; 
involves a significant die-off of any marine mammal population; and 
demands immediate response. Two UMEs are ongoing and under 
investigation relevant to the HRG survey area for species for which 
authorization of take is proposed. These involve humpback whales and 
minke whales. There is currently no direct connection between the UMEs, 
as there is no evident cause of stranding or death that is common 
across the species involved in the UMEs. Additionally, strandings 
across the two species are not clustering in space or time. We are 
proposing to take only limited numbers of humpback (10) and minke whale 
(17) by Level B harassment in the form of minor, short-term behavioral 
modifications that are unlikely to directly or indirectly result in 
strandings or mortality.
    Based on the foregoing preliminary information, direct physical 
interactions (ship strikes and entanglements) appear to be responsible 
for many of the UME mortalities recorded. The HRG survey with the 
proposed mitigation and monitoring is not likely to result in any 
mortalities. Fishing gear and in-water lines will not be employed by 
the survey vessel, and ship speed and avoidance mitigation measures 
will minimize risk of ship strikes.
    The proposed mitigation measures are expected to reduce the number 
and/or severity of takes by preventing animals from being exposed to 
sound levels that have the potential to cause Level B harassment during 
HRG survey activities. Vessel strike avoidance requirements will 
further mitigate potential impacts to marine mammals during vessel 
transit to and within the survey area.
    Avangrid did not request, and NMFS is not proposing to authorize, 
take of marine mammals by serious injury or mortality. NMFS expects 
that most takes would primarily consist of short-term Level B 
behavioral harassment in the form of temporary vacating of the area or 
decreased foraging (if such activity were occurring). These reactions 
are considered to be of low severity and with no lasting biological 
consequences (e.g., Southall et al., 2007). Since the source is mobile, 
a specified area would be ensonified by sound levels that could result 
in take for only a short period. Additionally, required mitigation 
measures would reduce exposure to sound that could result in 
harassment.
    In summary, and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality or injury is anticipated or authorized;
     Feeding behavior is not likely to be significantly 
impacted as effects on species that serve as prey species for marine 
mammals from the proposed survey are expected to be minimal;
     The availability of alternate areas of similar habitat 
value for marine mammals to temporarily vacate the survey area during 
the planned survey to avoid exposure to sounds from the activity;

[[Page 17405]]

     Take is anticipated to be by Level B behavioral harassment 
only, consisting of brief startling reactions and/or temporary 
avoidance of the survey area;
     While the survey area is within areas noted as 
biologically important for migration of the North Atlantic right whale, 
migration would not be affected since project activities would occur in 
such a comparatively small area. In addition, mitigation measures will 
be required to shut down sound sources at 500 m to further minimize any 
potential for effects to this species; and
     The proposed mitigation measures, including visual 
monitoring and shutdowns, are expected to minimize potential impacts to 
marine mammals, particularly in light of the small size of the take 
zones.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. Additionally, other qualitative 
factors may be considered in the analysis, such as the temporal or 
spatial scale of the activities relative to the species.
    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 3 percent for 
the bottlenose dolphin Western North Atlantic, southern migratory 
coastal stock and less than one percent for all other species and 
stocks proposed for authorization). See Table 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 sizes of the affected species 
or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Endangered Species Act (ESA)

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

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to Avangrid for HRG survey activities during geophysical 
survey activities off the Coast of Virginia and North Carolina from 
June 1, 2019, through May 31, 2020, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. A 
draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed HRG 
survey. We also request comment on the potential for renewal of this 
proposed IHA as described in the paragraph below. Please include with 
your comments any supporting data or literature citations to help 
inform our final decision on the request for MMPA authorization.
    On a case-by-case basis, NMFS may issue a one-year IHA renewal with 
an expedited public comment period (15 days) when (1) another year of 
identical or nearly identical activities as described in the Specified 
Activities section is planned or (2) the activities would not be 
completed by the time the IHA expires and a second IHA would allow for 
completion of the activities beyond that described in the Dates and 
Duration section, provided all of the following conditions are met:
     A request for renewal is received no later than 60 days 
prior to expiration of the current IHA.
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
proposed Renewal are identical to the activities analyzed under the 
initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take 
because only a subset of the initially analyzed activities remain to be 
completed under the Renewal); and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: April 22, 2019.
Catherine Marzin,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2019-08361 Filed 4-24-19; 8:45 am]
BILLING CODE 3510-22-P