Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Installation of the Block Island Wind Farm Export and Inter-Array Cables, 22216-22232 [2016-08729]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 81, Number 73 (Friday, April 15, 2016)]
[Notices]
[Pages 22216-22232]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-08729]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XE498


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Installation of the Block 
Island Wind Farm Export and Inter-Array Cables

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

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

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SUMMARY: NMFS has received an application from Deepwater Wind Block 
Island, LLC (DWBI) for an Incidental Harassment Authorization (IHA) to 
take marine mammals, by harassment, incidental to the installation of 
the Block Island Wind Farm (BIWF) Export and Inter-Array Cables. 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an IHA to DWBI to incidentally take, 
by Level B harassment only, small numbers of marine mammals during the 
specified activity.

DATES: Comments and information must be received no later than May 16, 
2016.

ADDRESSES: Comments on DWBI's IHA application (the application) should 
be addressed to Jolie Harrison, Chief, Permits and Conservation 
Division, Office of Protected Resources, National Marine Fisheries 
Service, 1315 East-West Highway, Silver Spring, MD 20910. The mailbox 
address for providing email comments is itp.fiorentino@noaa.gov. 
Comments sent via email, including all attachments, must not exceed a 
25-megabyte file size. NMFS is not responsible for comments sent to 
addresses other than those provided here.
    Instructions: All comments received are a part of the public record 
and will generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental/ without change. All Personal Identifying Information (for 
example, name, address, etc.) 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: John Fiorentino, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION: 

Availability

    An electronic copy of the application and supporting documents, as 
well as a list of the references cited in this document, may be 
obtained by visiting the Internet at: www.nmfs.noaa.gov/pr/permits/incidental/. In case of problems accessing these documents, please call 
the contact listed above.

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 
as ``an impact 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.''
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: Any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild [Level A harassment]; or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering [Level B harassment].

Summary of Request

    On March 11, 2016, NMFS received an application from DWBI for the 
taking of marine mammals incidental to the installation of the BIWF 
export and inter-array cables. This work was originally authorized by 
NMFS as part of a September 2014 (modified in June 2015) IHA issued to 
DWBI for construction of the BIWF (offshore installation of wind 
turbine generator [WTG] jacket foundations and export/inter-array cable 
installation [79 FR 53409]); however, only the construction activities 
associated with the WTG jacket foundation installation were performed 
during that one-year authorization which expired in October 2015. DWBI 
has, therefore, reapplied for a new IHA to complete the remaining 
export and inter-array cable installation activities. The proposed 
export and inter-array cable installation activities

[[Page 22217]]

remain the same as those described in the Federal Register notice for 
the original 2014 BIWF IHA. NMFS determined that the application was 
adequate and complete on March 14, 2016.
    DWBI has begun construction of the BIWF, a 30 megawatt offshore 
wind farm. Construction activities began in July of 2015 with the 
installation of the five WTG foundations. The submarine cable (export 
and inter-array cables) installation is scheduled to occur sometime 
between May and October, 2016. Use of dynamically positioned (DP) 
vessel thrusters during cable installation may result in the take of 
marine mammals. Take, by Level B Harassment only, of individuals of 
nine species is anticipated to result from the specified activity.

Description of the Specified Activity

Overview

    The BIWF will consist of five, 6 megawatt WTGs, a submarine cable 
interconnecting the WTGs, and a transmission cable. The WTG jacket 
foundations were installed in 2015. Erection of the five WTGs, 
installation of the inter-array and export cable, and construction of 
the onshore components of the BIWF is planned for 2016. The generation 
of underwater noise during use of vessel thrusters while the cable 
laying vessel is keeping position by its DP system during installation 
activities may result in the incidental take of marine mammals.

Dates and Duration

    BIWF cable installation activities are scheduled to occur sometime 
between May and October, 2016. NMFS is proposing to issue an 
authorization effective May 2016 through April 2017, based on the 
anticipated work window for the in-water cable installation activities 
construction that could result in the incidental take of marine 
mammals. While project activities may occur for over a 6-month period, 
use of the DP vessel thruster during cable installation activities is 
expected to occur for approximately 28 days. Cable installation (and 
subsequent use of the DP vessel thruster) would be conducted 24 hours 
per day.

Specified Geographic Region

    The offshore components of the BIWF will be located in state 
territorial waters. The WTGs will be located on average of about 4.8 
kilometers (km) southeast of Block Island, and about 25.7 km south of 
the Rhode Island mainland. The WTGs will be arranged in a radial 
configuration spaced about 0.8 km apart. The inter-array cable will 
connect the five WTGs for a total length of 3.2 km from the 
northernmost WTG to the southernmost WTG (Figure 1-1 of DWBI's 
application). Water depths along the inter-array cable range up to 23.3 
meters (m). The export cable will originate at the northernmost WTG and 
travel 10 km to a manhole located in the town of New Shoreham (Block 
Island) in Washington County, Rhode Island. Water depths along the 
export cable submarine route range up to 36.9 m. Construction staging 
and laydown for offshore construction is planned to occur at the Port 
of Providence, Providence, Rhode Island.
    The inter-array cable and submarine portions of the export cable 
will be installed by a jet plow supported by a DP vessel.

Detailed Description of Activities

    DWBI would use a jet plow, supported by a DP cable installation 
barge, to install the export cable and inter-array cable below the 
seabed. The jet plow would be positioned over the trench and pulled 
from shore by the cable installation vessel. The jet plow would be 
pulled along the seafloor behind the cable-laying barge with assistance 
of a non-DP material barge. High-pressure water from vessel- mounted 
pumps would be injected into the sediments through nozzles situated 
along the plow, causing the sediments to temporarily fluidize and 
create a liquefied trench. DWBI anticipates a temporary trench width of 
up to 1.5 m. As the plow is pulled along the route behind the barge, 
the cable would be laid into the temporary, liquefied trench through 
the back of the plow. The trench would be backfilled by the water 
current and the natural settlement of the suspended material. Umbilical 
cords would connect the submerged jet plow to control equipment on the 
vessel to allow the operators to monitor and control the installation 
process and make adjustments to the speed and alignment as the 
installation proceeds across the water.
    The Export Cable and Inter-Array Cable would be buried to a target 
depth of 1.8 m beneath the seafloor. The actual burial depth depends on 
substrate encountered along the route and could vary from 1.2 to 2.4 m. 
If less than 1.2 m burial is achieved, DWBI may elect to install 
additional protection, such as concrete matting or rock piles. At each 
of the WTGs, the Inter-Array cable would be pulled into the jacket 
foundation through J-tubes installed on the sides of the jacket 
foundations. At the J-tubes, additional cable armoring such as sand 
bags and/or rocks would be used to protect the inter-array cable.
    A DP vessel would be used during cable installation in order to 
maintain precise coordinates. DP systems maintain their precise 
coordinates in waters through the use of automatic controls. These 
control systems use variable levels of power to counter forces from 
current and wind. During cable-lay activities, DWBI expects that a 
reduced 50 percent power level will be used by DP vessels. DWBI modeled 
scenarios using a source level of 180 dB re 1 micro Pascal ([mu]Pa) for 
the DP vessel thruster, assuming water depths of 7, 10, 20, and 40 m, 
and thruster power of 50 percent. Detailed information on the acoustic 
modeling for this source is provided in Appendix A of DWBI's 
application. Installation of the export cable and inter-array cable is 
expected to take approximately 28 days. Cable installation will occur 
24 hours per day, seven days a week.

Description of Marine Mammals in the Area of the Specified Activity

    There are 38 species of marine mammals protected under the MMPA 
that potentially occur within the marine waters around Rhode Island 
Sound (see Table 3-1 of DWBI's application). The majority of these 
species are pelagic and/or northern species, or are so rarely sighted 
that their presence in the project area is unlikely. Six marine mammal 
species are listed under the Endangered Species Act (ESA) and are known 
to be present, at least seasonally, in the waters of Southern New 
England: Blue whale, fin whale, humpback whale, right whale, sei whale, 
and sperm whale. These species are highly migratory and do not spend 
extended periods of time in a localized area; the waters of Southern 
New England are primarily used as a stopover point for these species 
during seasonal movements north or south between important feeding and 
breeding grounds. While fin, humpback, and right whales have the 
potential to occur within the project area, the sperm, blue, and sei 
whales are more pelagic and/or northern species, and their presence 
within the shallow waters of the project area is unlikely. Because the 
potential for sperm, blue, and sei whales to occur within the project 
area during the marine construction period is unlikely, these species 
will not be described further in this analysis.
    The following species are both common in the waters of Rhode Island 
Sound and have the highest likelihood of occurring, at least 
seasonally, in the project area: North Atlantic right whale (Eubalaena 
glacialis), humpback whale

[[Page 22218]]

(Megaptera novaeangliae), fin whale (Balaenoptera physalus), minke 
whale (Balaenoptera acutorostrata), harbor porpoise (Phocoena 
phocoena), Atlantic white-sided dolphin (Lagenorhynchus acutus), short-
beaked common dolphin (Delphinus delphis), harbor seal (Phoca 
vitulina), and gray seal (Halichorus grypus) (Right Whale Consortium, 
2014) (Table 1).
    Further information on the biology, ecology, abundance, and 
distribution of those species likely to occur in the project area can 
be found in section 4 of the application (which NMFS has reviewed and 
concluded as adequate), and the NMFS Marine Mammal Stock Assessment 
Reports (see Waring et al., 2015), which are available online at: 
https://www.nmfs.noaa.gov/pr/sars/. Marine mammal species descriptions 
are also available online at: https://www.nmfs.noaa.gov/pr/species/mammals/.

                                               Table 2--Marine Mammals Likely To Occur in the Project Area
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                                                                                                   Stock
             Common name                    Scientific name              NMFS status             abundance                       Stock
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                                                               Toothed Whales (Odontoceti)
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Atlantic white-sided dolphin.........  Lagenorhynchus acutus...  N/A........................          48,819  W. North Atlantic.
Short-beaked common dolphin..........  Delphinus delphis.......  N/A........................         120,743  W. North Atlantic.
Harbor porpoise......................  Phocoena phocoena.......  N/A........................          79,833  Gulf of Maine/Bay of Fundy.
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                                                                Baleen Whales (Mysticeti)
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Minke whale..........................  Balaenoptera              N/A........................          20,741  Canadian East Coast.
                                        acutorostrata.
Fin whale............................  Balaenoptera physalus...  Endangered.................           1,618  W. North Atlantic.
Humpback whale.......................  Megaptera novaeangliae..  Endangered.................             823  Gulf of Maine.
North Atlantic right whale...........  Eubalaena glacialis.....  Endangered.................             465  W. North Atlantic.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Earless Seals (Phocidae)
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Gray seals...........................  Halichoerus grypus......  N/A........................         348,900  North Atlantic.
Harbor seals.........................  Phoca vitulina..........  N/A........................          75,834  W. North Atlantic.
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Sources: Waring et al., 2015; Waring et al., 2013; Waring et al., 2011; Warring et al., 2010; RI SAMP, 2011; Kenney and Vigness-Raposa, 2009; NMFS,
  2012.

Potential Effects of the Specified Activity on Marine Mammals

    This section includes a summary and discussion of the ways that the 
types of stressors associated with the specified activity have been 
observed to impact marine mammals. This discussion may also include 
reactions that we consider to rise to the level of a take and those 
that we do not consider to rise to the level of a take (for example, 
with acoustics, we may include a discussion of studies that showed 
animals not reacting at all to sound or exhibiting barely measurable 
avoidance). This section is intended as a background of potential 
effects and does not consider either the specific manner in which this 
activity will be carried out or the mitigation that will be 
implemented, and how either of those will shape the anticipated impacts 
from this specific activity. The ``Estimated Take by Incidental 
Harassment'' section later in this document will include a quantitative 
analysis of the number of individuals that are expected to be taken by 
this activity. The ``Negligible Impact Analysis'' section will include 
the analysis of how this specific activity will impact marine mammals 
and will consider the content of this ``Potential Effects of the 
Specified Activity on Marine Mammals'' section, the ``Estimated Take by 
Incidental Harassment'' section, the ``Proposed Mitigation'' section, 
and the ``Anticipated Effects on Marine Mammal Habitat'' section to 
draw conclusions regarding the likely impacts of this activity on the 
reproductive success or survivorship of individuals, and from that on 
the affected marine mammal populations 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 hertz (Hz) or kilohertz (kHz), while sound 
level describes the sound's intensity and is measured in decibels (dB). 
Sound level increases or decreases exponentially with each dB of 
change. The logarithmic nature of the scale means that each 10-dB 
increase is a 10-fold increase in acoustic power (and a 20-dB increase 
is then a 100-fold increase in power). A 10-fold increase in acoustic 
power does not mean that the sound is perceived as being 10 times 
louder, however. Sound levels are compared to a reference sound 
pressure (micro-Pascal) to identify the medium. For air and water, 
these reference pressures are ``re: 20 [mu]Pa'' and ``re: 1 [mu]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

    Use of the DP vessel thrusters during the BIWF project 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)

[[Page 22219]]

foraging; (3) orientation; and (4) predator detection. Interference 
with producing or receiving these sounds may result in adverse impacts. 
Audible distance, or received levels of sound depend on the nature of 
the sound source, ambient noise conditions, and the sensitivity of the 
receptor to the sound (Richardson et al., 1995). Type and significance 
of marine mammal reactions to sound are likely dependent on a variety 
of factors including, but not limited to, (1) the behavioral state of 
the animal (e.g., feeding, traveling, etc.); (2) frequency of the 
sound; (3) distance between the animal and the source; and (4) the 
level of the sound relative to ambient conditions (Southall et al., 
2007).
    When considering the influence of various kinds of sound on the 
marine environment, it is necessary to understand that different kinds 
of marine life are sensitive to different frequencies of sound. Current 
data indicate that not all marine mammal species have equal hearing 
capabilities (Richardson et al., 1995; Southall et al., 1997; Wartzok 
and Ketten, 1999; Au and Hastings, 2008).
    Southall et al. (2007) designated ``functional hearing groups'' for 
marine mammals based on available behavioral data; audiograms derived 
from auditory evoked potentials; anatomical modeling; and other data. 
Southall et al. (2007) also estimated the lower and upper frequencies 
of functional hearing for each group. However, animals are less 
sensitive to sounds at the outer edges of their functional hearing 
range and are more sensitive to a range of frequencies within the 
middle of their functional hearing range. Note that direct measurements 
of hearing sensitivity do not exist for all species of marine mammals, 
including low-frequency cetaceans. The functional hearing groups and 
the associated frequencies developed by Southall et al. (2007) were 
revised by Finneran and Jenkins (2012) and have been further modified 
by NOAA. Table 2 provides a summary of sound production and general 
hearing capabilities for marine mammal species (note that values in 
this table are not meant to reflect absolute possible maximum ranges, 
rather they represent the best known ranges of each functional hearing 
group). For purposes of the analysis in this document, marine mammals 
are arranged into the following functional hearing groups based on 
their generalized hearing sensitivities: High-frequency cetaceans, mid-
frequency cetaceans, low-frequency cetaceans (mysticetes), phocids 
(true seals), and otariids (sea lion and fur seals). A detailed 
discussion of the functional hearing groups can be found in Southall et 
al. (2007) and Finneran and Jenkins (2012).

            Table 3--Marine Mammal Functional Hearing Groups
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     Functional hearing group            Functional hearing range*
------------------------------------------------------------------------
Low-frequency (LF) cetaceans       7 Hz to 25 kHz.
 (baleen whales).
Mid-frequency (MF) cetaceans       150 Hz to 160 kHz.
 (dolphins, toothed whales,
 beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans      200 Hz to 180 kHz.
 (true porpoises, Kogia, river
 dolphins, cephalorhynchid,
 Lagenorhynchus cruciger and L.
 australis).
Phocid pinnipeds (underwater)      75 Hz to 100 kHz.
 (true seals).
Otariid pinnipeds (underwater)     100 Hz to 48 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
Adapted and derived from Southall et al. (2007).
* Represents frequency band of hearing for entire group as a composite
  (i.e., all species within the group), where individual species'
  hearing ranges are typically not as broad. Functional hearing is
  defined as the range of frequencies a group hears without
  incorporating non-acoustic mechanisms (Wartzok and Ketten, 1999). This
  is ~60 to ~70 dB above best hearing sensitivity (Southall et al.,
  2007) for all functional hearing groups except LF cetaceans, where no
  direct measurements on hearing are available. For LF cetaceans, the
  lower range is based on recommendations from Southall et al., 2007 and
  the upper range is based on information on inner ear anatomy and
  vocalizations.

    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). 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.
    As mentioned previously in this document, nine marine mammal 
species (seven cetaceans and two pinnipeds) are most likely to occur in 
the project area. Of the seven cetacean species likely to occur in the 
project area, four are classified as low-frequency cetaceans (i.e., 
minke whale, fin whale, humpback whale, and North Atlantic right 
whale), two are classified as mid-frequency cetaceans (i.e., Atlantic 
white-sided dolphin and short-beaked common dolphin), and one is 
classified as a high-frequency cetacean (i.e., harbor porpoise) 
(Southall et al., 2007). A species' functional hearing group is a 
consideration when we analyze the effects of exposure to sound on 
marine mammals.

Hearing Impairment

    Marine mammals may experience temporary or permanent hearing 
impairment when exposed to loud sounds. Hearing impairment is

[[Page 22220]]

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 presumed to be 
likely if the hearing threshold is reduced by >=40 dB (that is, 40 dB 
of TTS). 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 longer 
durations of exposure necessary to cause PTS as compared with TTS, it 
is considerably less likely that PTS would occur during DP vessel 
thruster use associated with the cable laying activities.

Temporary Threshold Shift (TTS)

    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 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 [Delphinapterus leucas], harbor 
porpoise, and Yangtze finless porpoise [Neophocoena asiaeorientalis]) 
and three species of pinnipeds (northern elephant seal, harbor seal, 
and California sea lion) exposed to a limited number of sound sources 
(i.e., mostly tones and octave-band noise) in laboratory settings 
(e.g., Finneran et al., 2002 and 2010; Nachtigall et al., 2004; Kastak 
et al., 2005; Lucke et al., 2009; Mooney et al., 2009; Popov et al., 
2011; Finneran and Schlundt, 2010). In general, harbor seals (Kastak et 
al., 2005; Kastelein et al., 2012a) and harbor porpoises (Lucke et al., 
2009; Kastelein et al., 2012b) have a lower TTS onset than other 
measured pinniped or 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 dB rms 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 (NEFSC, 2014). Additionally, the existing marine mammal TTS 
data come from a limited number of individuals within these species. 
There are no data available on noise-induced hearing loss for 
mysticetes. For summaries of data on TTS in marine mammals or for 
further discussion of TTS onset thresholds, please see Southall et al. 
(2007), Finneran and Jenkins (2012), 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 SPL) of longer 
duration were found to induce TTS onset more than louder sounds (higher 
SPL) of shorter duration. 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. Southall et al. (2007) considers a 6 dB TTS (that is, 
baseline thresholds are elevated by 6 dB) to be a sufficient definition 
of TTS-onset. 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.
    Although the duration of the DP thruster sound source has the 
potential to induce TTS onset, animals in the project during the inter-
array and export cable installation activities are not expected to 
incur more than mild TTS hearing impairment due to low source levels 
and the fact that most marine mammals would more likely avoid a loud 
sound source rather than swim in such close proximity as to result in 
TTS. 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. Chronic exposure to 
excessive, though not high-intensity, noise has the potential to cause 
masking at particular frequencies for marine mammals that utilize sound 
for vital biological functions (Clark et al. 2009). 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. 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

[[Page 22221]]

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; Chapman et al., 1998; 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. Therefore, since noise generated from vessels dynamic 
positioning activity is mostly concentrated at low frequency ranges, it 
may have less effect on high frequency echolocation sounds by 
odontocetes (toothed whales).
    As the DP vessel is continually moving along the cable route over a 
24-hour period, the area within the 120 dB isopleth is constantly 
moving and shifting within a 24-hour period.
    Therefore, no single area in Rhode Island Sound will have noise 
levels above 120 dB for more than a few hours. While continuous sound 
from the DP thruster when in use is predicted to extend up to 4.75 km 
to the 120 dB threshold, the low source levels, coupled with the 
likelihood of animals to avoid the sound source, would result in very 
little opportunity for this activity to mask the communication of local 
marine mammals for more than a brief period of time.

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; Sapolsky et al., 2005; 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; Wright et al., 2008). 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.

[[Page 22222]]

    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, or low-frequency sounds. For example, Jansen (1998) reported 
on the relationship between acoustic exposures and physiological 
responses that are indicative of stress responses in humans (for 
example, elevated respiration and increased heart rates). Jones (1998) 
reported on reductions in human performance when faced with acute, 
repetitive exposures to acoustic disturbance. Trimper et al. (1998) 
reported on the physiological stress responses of osprey to low-level 
aircraft noise while Krausman et al. (2004) reported on the auditory 
and physiology stress responses of endangered Sonoran pronghorn to 
military overflights. Smith et al. (2004a, 2004b), for example, 
identified noise-induced physiological transient stress responses in 
hearing-specialist fish (i.e., goldfish) that accompanied short- and 
long-term hearing losses. Welch and Welch (1970) reported physiological 
and behavioral stress responses that accompanied damage to the inner 
ears of fish and several mammals.
    Hearing is one of the primary senses marine mammals use to gather 
information about their environment and to communicate with 
conspecifics. Although empirical information on the relationship 
between sensory impairment (TTS, PTS, and acoustic masking) on marine 
mammals remains limited, it seems reasonable to assume that reducing an 
animal's ability to gather information about its environment and to 
communicate with other members of its species would be stressful for 
animals that use hearing as their primary sensory mechanism. Therefore, 
we assume that acoustic exposures sufficient to trigger onset PTS or 
TTS would be accompanied by physiological stress responses because 
terrestrial animals exhibit those responses under similar conditions 
(NRC, 2003). More importantly, marine mammals might experience stress 
responses at received levels lower than those necessary to trigger 
onset TTS. Based on empirical studies of the time required to recover 
from stress responses (Moberg, 2000), we also assume that stress 
responses are likely to persist beyond the time interval required for 
animals to recover from TTS and might result in pathological and pre-
pathological states that would be as significant as behavioral 
responses to TTS.
    In general, there are few data on the potential for strong, 
anthropogenic underwater sounds to cause non-auditory physical effects 
in marine mammals. Such effects, if they occur at all, would presumably 
be limited to short distances and to activities that extend over a 
prolonged period. The available data do not allow identification of a 
specific exposure level above which non-auditory effects can be 
expected (Southall et al., 2007). There is no definitive evidence that 
any of these effects occur even for marine mammals in close proximity 
to an anthropogenic sound source. In addition, marine mammals that show 
behavioral avoidance of vessels and related sound sources, are unlikely 
to incur non-auditory impairment or other physical effects. NMFS does 
not expect that the generally short-term and transitory cable 
installation activities would create conditions of long-term, 
continuous noise 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). 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.
    In the Southall et al. (2007) publication, for the purposes of 
analyzing responses of marine mammals to anthropogenic sound and 
developing criteria, the authors differentiate between pulse sounds 
(single and multiple) and non-pulse sounds.
    The studies that address responses of low-frequency cetaceans to 
non-pulse sounds sounds (such as the sound emitted from a DP vessel 
thruster) 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 
non-pulse 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 responses of high-frequency cetaceans to 
non-pulse sounds include data gathered both in

[[Page 22223]]

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. 
Southall et al. (2007) concluded that the existing data indicate that 
harbor porpoises are likely sensitive to a wide range of anthropogenic 
sounds at low received levels (around 90 to 120 dB), at least for 
initial exposures. All recorded exposures above 140 dB induced profound 
and sustained avoidance behavior in wild harbor porpoises (Southall et 
al., 2007). Rapid habituation was noted in some but not all studies.
    The studies that address the responses of pinnipeds in water to 
non-pulse sounds include data gathered both in the field and the 
laboratory and related to several different sound sources, including: 
AHDs, various non-pulse sounds used in underwater data communication, 
underwater drilling, and construction noise. Few studies exist with 
enough information to include them in the analysis. The limited data 
suggest that exposures to non-pulse sounds between 90 and 140 dB 
generally do not result in strong behavioral responses of pinnipeds in 
water, but no data exist at higher received levels (Southall et al., 
2007).
    The low source level and relatively short duration of the DP vessel 
thrusters during cable installation activities would likely result in 
only brief startling reactions or short-term and temporary avoidance of 
the area, rather than permanent abandonment, by marine mammals.

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, toothed whales, and (less frequently) pinnipeds have been shown 
to react behaviorally to underwater sound from sources such as airgun 
pulses or vessels under some conditions, at other times, mammals of all 
three types have shown no overt reactions (e.g., Malme et al., 1986; 
Richardson et al., 1995; Madsen and Mohl, 2000; Croll et al., 2001; 
Jacobs and Terhune, 2002; Madsen et al., 2002; Miller et al., 2005). In 
general, pinnipeds seem to be more tolerant of exposure to some types 
of underwater sound than are baleen whales. Richardson et al. (1995) 
found that vessel sound does not seem to strongly affect pinnipeds that 
are already in the water. Richardson et al. (1995) went on to explain 
that seals on haul-outs sometimes respond strongly to the presence of 
vessels and at other times appear to show considerable tolerance of 
vessels, and Brueggeman et al. (1992) observed ringed seals (Pusa 
hispida) hauled out on ice pans displaying short-term escape reactions 
when a ship approached within 0.16-0.31 mi (0.25-0.5 km).

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 kts).
    Given the slow vessel speeds and predictable course necessary for 
jet-plowing and related cable installation activities for the BIWF 
project, ship strike is unlikely to occur. Marine mammals would be able 
to easily avoid vessels and are likely already habituated to the 
presence of numerous vessels in the area. Right whales have been 
observed in or near Rhode Island during all four seasons; however, they 
are most common in the spring when they are migrating and in the fall 
during their southbound migration (Kenney and Vigness-Raposa, 2009). 
Portions of the BIWF project area are located within the NMFS-
designated Mid-Atlantic seasonal management area (SMA) (see 50 CFR 
224.105); thus, to minimize the potential for vessel collision with 
right whales and other marine mammal species all DWBI vessels 
associated with the BIWF construction will operate at speeds of 10 
knots or less from the November 1 to April 30 time period, regardless 
of whether they are inside or outside of the designated SMA. In 
addition, all DWBI vessels associated with the BIWF construction will 
adhere to NMFS guidelines for marine mammal ship striking avoidance 
(available online at: https://www.nmfs.noaa.gov/pr/pdfs/education/viewing_northeast.pdf), including maintaining a distance of at least 
1,500 feet from right whales and having dedicated protected species 
observers who will communicate with the captain to ensure that all 
measures to avoid whales are taken. NMFS believes that the size of 
right whales, their slow movements, and the amount of time they spend 
at the surface will make them extremely likely to be spotted by 
protected species observers during construction activities within the 
BIWF project area.

Anticipated 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. There is also no designated critical habitat for any ESA-listed 
marine mammals. Harbor seals haul out on Block Island and points along 
Narragansett Bay, the most important haul-out being on the edge of New 
Harbor, about 2.4 km from the proposed BIWF landfall on Block Island. 
The only consistent haul-out locations for gray seals within the 
vicinity of Rhode Island are around Monomoy National Wildlife Refuge 
and Nantucket Sound in Massachusetts (more than 80 nautical miles from 
the proposed project area). As discussed above, NMFS' regulations at 50 
CFR 224 designated the nearshore

[[Page 22224]]

waters of the Mid-Atlantic Bight as the Mid-Atlantic U.S. 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.
    The BIWF involves activities that would disturb the seafloor and 
potentially affect benthic and finfish communities. Installation of the 
inter-array cable and export cable would result in the temporary 
disturbance of no more than 3.7 and 11.6 acres of seafloor, 
respectively. These installation activities would also result in 
temporary and localized increases in turbidity around the proposed 
project area. DWBI may also be required to install additional 
protective armoring in areas where the burial depth achieved is less 
than 1.2 m. DWBI expects that additional protection would be required 
at a maximum of 1 percent of the entire submarine cable, resulting in a 
conversion of up to 0.4 acres of soft substrate to hard substrate along 
the cable route. During the installation of additional protective 
armoring at the cable crossings and as necessary along the cable route, 
anchors and anchor chains would temporarily impact about 1.8 acres of 
bottom substrate during each anchoring event.
    Jet-plowing and impacts from construction vessel anchor placement 
and/or sweep would cause either the displacement or loss of benthic and 
finfish resources in the immediate areas of disturbance. This may 
result in a temporary loss of forage items and a temporary reduction in 
the amount of benthic habitat available for foraging marine mammals in 
the immediate proposed project area. However, the amount of habitat 
affected represents a very small percentage of the available foraging 
habitat in the proposed project area. It is likely that marine mammals 
may temporarily shift their foraging efforts to other areas within or 
around the project area. While this would affect the movements of 
individual marine mammals, it is likely to be temporary and is not 
likely to affect marine mammal nourishment or result in any injury or 
mortality. Increased underwater sound levels may temporarily result in 
marine mammals avoiding or abandoning the area.
    Because of the temporary nature of the disturbance, the 
availability of similar habitat and resources in the surrounding area, 
and the lack of important or unique marine mammal 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.

Mitigation

    In order to issue an incidental take authorization 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 adverse 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 (where relevant).

Proposed Mitigation Measures

    With NMFS' input during the application process, DWBI is proposing 
the following mitigation measures during cable installation operations 
using DP vessel thruster use. These mitigation measures were also 
reviewed and approved by NMFS for the BIWF IHA issued in 2014 and 
amended in June 2015, and are consistent with the terms and conditions 
of the amended Incidental Take Statement for the Biological Opinion on 
the Construction and Operation of the Block Island Wind Farm:
    Exclusion and Monitoring Zones: Exclusion zones (defined by NMFS as 
the Level A harassment zone of influence [ZOI] out to the 180/190 dB 
isopleth) and monitoring zones (defined by NMFS as the Level B 
harassment ZOI out to the 120 dB isopleth for continuous noise) are 
typically established to minimize impacts to marine mammals. However, 
noise analysis has indicated that DP vessel thruster use will not 
produce sound levels at 180/190 dB at any appreciable distance (see 
DWBI's Underwater Acoustic Modeling Report in Appendix A of the 
application). This is consistent with acoustic modeling results for 
other Atlantic wind farm projects using DP vessel thrusters (Tetra 
Tech, 2014; DONG Energy, 2016), as well as subsea cable-laying 
activities using DP vessel thruster use (Quintillion, 2015 and 2016). 
Therefore, injury to marine mammals is not expected and no Level A 
harassment exclusion zone is proposed.
    Consultation with NMFS has indicated that the monitoring zones 
established out to the 120 dB isopleth for continuous noise will result 
in zones too large to effectively monitor (up to 4.75 km). Therefore, 
based on precedent set by the U.S. Department of the Navy and recent 
European legislation regarding compliance thresholds for wind farm 
construction noise (DoN, 2012; OSPAR, 2008), and consistent with the 
previous IHA's issued to DWBI and Deepwater Wind Block Island 
Transmission, L.L.C. (DWBITS), DWBI will establish a monitoring zone 
equivalent, at a minimum, to the size of the predicted 160 dB isopleth 
for DP vessel thruster use (5-m radius from the DP vessel) based on 
DWBI's underwater acoustic modeling. All marine mammal sightings which 
are visually feasible beyond the 160 dB isopleth will be recorded and 
potential takes will be noted.
    DP Thruster Power Reduction--During cable installation a constant 
tension must be maintained to ensure the integrity of the cable. Any 
significant stoppage in vessel maneuverability during jet plow 
activities has the potential to result in significant damage to the 
cable. Therefore, during cable lay if marine mammals enter or approach 
the established 160 dB isopleth monitoring zone, DWBI proposes to 
reduce DP thruster to the maximum extent possible, except under 
circumstances when reducing DP thruster use would compromise safety 
(both human health and environmental) and/or the integrity of the 
Project. Reducing thruster energy will effectively reduce the potential 
for exposure of marine mammals to sound energy. After decreasing 
thruster energy, protected species observers (PSOs) will continue to 
monitor marine mammal behavior and determine if the animal(s) is moving 
towards or away from the established monitoring zone. If the animal(s) 
continues to move towards the sound source then DP thruster use would 
remain at the reduced level. Normal thruster use will resume when PSOs 
report that marine mammals have moved away from and remained clear of 
the monitoring zone for a minimum of 30 minutes since last the 
sighting.
    Vessel Speed Restrictions--To minimize the potential for vessel 
collision with North Atlantic right whales and other marine mammals, 
all DWBI project vessels shall operate at speeds of 10 knots or less 
from November 1 through April 30.
    Ship Strike Avoidance--DWBI shall adhere to NMFS guidelines for 
marine mammal ship strike avoidance (https://www.nmfs.noaa.gov/pr/pdfs/education/viewing_northeast.pdf).

Mitigation Conclusions

    NMFS has carefully evaluated DWBI's mitigation measures in the 
context of ensuring that we prescribe the means of effecting the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat. Our evaluation of potential measures

[[Page 22225]]

included consideration of the following factors in relation to one 
another:
     The manner in which, and the degree to which, the 
successful implementation of the measure is expected to minimize 
adverse impacts to marine mammals;
     The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned; and
     The practicability of the measure for applicant 
implementation.
    Any mitigation measure(s) prescribed by NMFS should be able to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to the accomplishment of one or more of 
the general goals listed here:
     Avoidance or minimization of injury or death of marine 
mammals wherever possible (goals 2, 3, and 4 may contribute to this 
goal).
     A reduction in the numbers of marine mammals (total number 
or number at biologically important time or location) exposed to 
received levels of activities that we expect to result in the take of 
marine mammals (this goal may contribute to 1, above, or to reducing 
harassment takes only).
     A reduction in the number of times (total number or number 
at biologically important time or location) individuals would be 
exposed to received levels of activities that we expect to result in 
the take of marine mammals (this goal may contribute to 1, above, or to 
reducing harassment takes only).
     A reduction in the intensity of exposures (either total 
number or number at biologically important time or location) to 
received levels of activities that we expect to result in the take of 
marine mammals (this goal may contribute to a, above, or to reducing 
the severity of harassment takes only).
     Avoidance or minimization of adverse effects to marine 
mammal habitat, paying special attention to the food base, activities 
that block or limit passage to or from biologically important areas, 
permanent destruction of habitat, or temporary destruction/disturbance 
of habitat during a biologically important time.
     For monitoring directly related to mitigation--an increase 
in the probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation.
    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 of 
effecting the least practicable impact on marine mammals species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

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 ITAs 
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.
    Monitoring measures prescribed by NMFS should accomplish one or 
more of the following general goals:
    1. An increase in our understanding of the likely occurrence of 
marine mammal species in the vicinity of the action, i.e., presence, 
abundance, distribution, and/or density of species.
    2. An increase in our understanding of the nature, scope, or 
context of the likely exposure of marine mammal species to any of the 
potential stressor(s) associated with the action (e.g. sound or visual 
stimuli), through better understanding of one or more of the following: 
The action itself and its environment (e.g. sound source 
characterization, propagation, and ambient noise levels); the affected 
species (e.g. life history or dive pattern); the likely co-occurrence 
of marine mammal species with the action (in whole or part) associated 
with specific adverse effects; and/or the likely biological or 
behavioral context of exposure to the stressor for the marine mammal 
(e.g. age class of exposed animals or known pupping, calving or feeding 
areas).
    3. An increase in our understanding of how individual marine 
mammals respond (behaviorally or physiologically) to the specific 
stressors associated with the action (in specific contexts, where 
possible, e.g., at what distance or received level).
    4. An increase in our understanding of how anticipated individual 
responses, to individual stressors or anticipated combinations of 
stressors, may impact either: The long-term fitness and survival of an 
individual; or the population, species, or stock (e.g. through effects 
on annual rates of recruitment or survival).
    5. An increase in our understanding of how the activity affects 
marine mammal habitat, such as through effects on prey sources or 
acoustic habitat (e.g., through characterization of longer-term 
contributions of multiple sound sources to rising ambient noise levels 
and assessment of the potential chronic effects on marine mammals).
    6. An increase in understanding of the impacts of the activity on 
marine mammals in combination with the impacts of other anthropogenic 
activities or natural factors occurring in the region.
    7. An increase in our understanding of the effectiveness of 
mitigation and monitoring measures.
    8. An increase in the probability of detecting marine mammals 
(through improved technology or methodology), both specifically within 
the safety zone (thus allowing for more effective implementation of the 
mitigation) and in general, to better achieve the above goals.

Proposed Monitoring Measures

    DWBI submitted a marine mammal monitoring and reporting plan as 
part of the IHA application. The plan may be modified or supplemented 
based on comments or new information received from the public during 
the public comment period.
    Visual Monitoring--Visual observation of the 160-dB monitoring zone 
established for DP vessel operation during cable installation will be 
performed by qualified and NMFS approved protected species observers 
(PSOs), the resumes of whom will be provided to NMFS for review and 
approval prior to the start of construction activities. Observer 
qualifications will include direct field experience on a marine mammal 
observation vessel and/or aerial surveys in the Atlantic Ocean/Gulf of 
Mexico. A minimum of two PSOs will be stationed aboard the cable lay 
vessel. Each PSO will monitor 360 degrees of the field of vision. PSOs 
stationed on the DP vessel will begin observation of the monitoring 
zone as the vessel initially leaves the dock. Observations of the 
monitoring zone will continue throughout the cable installation and 
will end after the DP vessel has returned to dock.
    Observers would estimate distances to marine mammals visually, 
using laser range finders, or by using reticle binoculars during 
daylight hours. During night operations, night vision binoculars will 
be used. If vantage points higher than 25 ft (7.6 m) are available, 
distances can be measured using inclinometers. Position data will be 
recorded using hand-held or vessel global positioning system (GPS) 
units

[[Page 22226]]

for each sighting, vessel position change, and any environmental 
change.
    Each PSO stationed on the cable lay vessel will scan the 
surrounding area for visual indication of marine mammal presence that 
may enter the monitoring zone. Observations will take place from the 
highest available vantage point on the cable lay vessel. General 360-
degree scanning will occur during the monitoring periods, and target 
scanning by the PSO will occur when alerted of a marine mammal 
presence.
    Data on all observations will be recorded based on standard PSO 
collection requirements. This will include dates and locations of 
construction operations; time of observation; location and weather; 
distance from sound source, DP vessel thruster status (i.e., energy 
level); details of marine mammal sightings (e.g., species, age 
classification [if known], numbers); details of any observed ``taking'' 
(behavioral disturbances or injury/mortality); and reaction of the 
animal(s) to relevant sound source (if any) and observed behavior, 
including bearing and direction of travel. All marine mammal sightings 
which are visually feasible beyond the 160 dB isopleth, will also be 
recorded and potential takes will be noted.
    In addition, prior to initiation of construction work, all crew 
members on barges, tugs and support vessels, will undergo environmental 
training, a component of which will focus on the procedures for 
sighting and protection of marine mammals. A briefing will also be 
conducted between the construction supervisors and crews, the PSOs, and 
DWBI. The purpose of the briefing will be to establish responsibilities 
of each party, define the chains of command, discuss communication 
procedures, provide an overview of monitoring purposes, and review 
operational procedures. The DWBI Construction Compliance Manager (or 
other authorized individual) will have the authority to stop or delay 
construction activities, if deemed necessary. New personnel will be 
briefed as they join the work in progress.
    Acoustic Field Verification--DWBI would perform field verification 
to confirm the 160-dB isopleth monitoring zone. Field verification 
during cable installation using DP thrusters will be performed using 
acoustic measurements from two reference locations at two water depths 
(a depth at mid-water and a depth at approximately 1 m above the 
seafloor). As necessary, the monitoring zone will be modified to ensure 
adequate protection to marine mammals.

Proposed Reporting Measures

    Observers would record dates and locations of construction 
operations; times of observations; location and weather; details of 
marine mammal sightings (e.g., species, age, numbers, behavior); and 
details of any observed take.
    DWBI proposes to provide the following notifications and reports 
during construction activities:
     Notification to NMFS and the U.S. Army Corps of Engineers 
(USACE) within 24-hours of beginning construction activities and again 
within 24-hours of completion;
     The USACE and NMFS should be notified within 24 hours 
whenever a monitoring zone is re-established by DWBI. After any re-
establishment of the monitoring zone, DWBI will provide a report to the 
USACE and NMFS detailing the field-verification measurements within 7 
days. This includes information, such as: a detailed account of the 
levels, durations, and spectral characteristics of DP thruster use, and 
the peak, RMS, and energy levels of the sound pulses and their 
durations as a function of distance, water depth, and tidal cycle. The 
USACE and NMFS will be notified within 24 hours if field verification 
measurements suggest a larger DP thruster power reduction zone.
     Within 120 days after completion of the construction 
activities, a final technical report will be provided to USACE, and 
NMFS that fully documents the methods and monitoring protocols, 
summarizes the data recorded during monitoring, estimates the number of 
marine mammals that may have been taken during construction activities, 
and provides an interpretation of the results and effectiveness of all 
monitoring tasks
     Notification of Injured or Dead Marine Mammals--In the 
unanticipated event that the specified activities clearly causes the 
take of a marine mammal in a manner prohibited by the IHA, such as a 
serious injury, or mortality (e.g., ship-strike, gear interaction, and/
or entanglement), DWBI 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 NOAA Greater Atlantic 
Regional Fisheries Office (GARFO) Stranding Coordinator. The report 
would include the following information:
    [cir] Time, date, and location (latitude/longitude) of the 
incident;
    [cir] Name and type of vessel involved;
    [cir] Vessel's speed during and leading up to the incident;
    [cir] Description of the incident;
    [cir] Status of all sound source use in the 24 hours preceding the 
incident;
    [cir] Water depth;
    [cir] Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    [cir] Description of all marine mammal observations in the 24 hours 
preceding the incident;
    [cir] Species identification or description of the animal(s) 
involved;
    [cir] Fate of the animal(s); and
    [cir] 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 DWBI to minimize 
reoccurrence of such an event in the future. DWBI would not resume 
activities until notified by NMFS.
    In the event that DWBI 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), DWBI would immediately report the incident to the Chief 
of the Permits and Conservation Division, Office of Protected Resources 
and the GARFO 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 the Applicant to determine if modifications in the 
activities are appropriate.
    In the event that DWBI 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), DWBI would report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the NMFS Greater Atlantic Regional Fisheries Office Regional 
Stranding Coordinator, within 24 hours of the discovery. DWBI would 
provide photographs or video footage (if available) or other 
documentation of the stranded animal sighting to NMFS. DWBI can 
continue its operations under such a case.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: Any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine

[[Page 22227]]

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].
    Underwater sound associated with the use of DP vessel thrusters 
during inter-array and export cable installation is the only project 
activity that has the potential to harass marine mammals, as defined by 
the MMPA. Harassment could take the form of temporary threshold shift, 
avoidance, or other changes in marine mammal behavior. NMFS anticipates 
that impacts to marine mammals would be in the form of Level B 
behavioral harassment and no take by injury, serious injury, or 
mortality is proposed. NMFS does not anticipate take resulting from the 
movement of vessels (i., vessel strike) associated with construction 
because there will be a limited number of vessels moving at slow speeds 
over a relatively shallow, nearshore area, and PSOs on the vessels will 
be monitoring for marine mammals and will be able to alert the vessels 
to avoid any marine mammals in the area.
    NMFS' current acoustic exposure criteria for estimating take are 
shown in Table 3 below. DWBI's modeled distances to these acoustic 
exposure criteria are shown in Table 4. Details on the model 
characteristics and results are provided in the Underwater Acoustic 
Modeling Report found in Appendix A of the application. As discussed in 
the application and in Appendix A, acoustic modeling took into 
consideration sound sources using the loudest potential operational 
parameters, bathymetry, geoacoustic properties of the project area, 
time of year, and marine mammal hearing ranges. Results from the 
acoustic modeling showed that estimated maximum critical distance to 
the 120 dB re 1 [mu]Pa (rms) MMPA threshold was approximately 4,750 m 
for 10-m water depth, 4,275 m for 20-m water depth, and 3,575 m for 40-
m water depth. More information on results including figures displaying 
critical distance information can be found in Appendix A. DWBI and NMFS 
believe that these estimates represent the worst-case scenario and that 
the actual distances to the Level B harassment threshold may be 
shorter. DP vessel thruster use will not produce sound levels at 180/
190 dB at any appreciable distance; therefore, no injurious (Level A 
harassment) takes have been requested or are being proposed for 
authorization. To verify the distance to the MMPA thresholds calculated 
by underwater acoustic modeling, DWBI has committed to conducting real-
time underwater acoustic measurements of the DP vessel thrusters. Field 
verification of actual sound propagation will enable adjustment of the 
MMPA threshold level distances to fit actual construction conditions, 
if necessary.

            Table 3--NMFS' Current Acoustic Exposure Criteria
------------------------------------------------------------------------
                           Non-Explosive Sound
-------------------------------------------------------------------------
           Criterion             Criterion definition       Threshold
------------------------------------------------------------------------
Level A Harassment (Injury)...  Permanent Threshold     180 dB re 1
                                 Shift (PTS) (Any        [micro]Pa-m
                                 level above that        (cetaceans)/190
                                 which is known to       dB re 1
                                 cause TTS).             [micro]Pa-m
                                                         (pinnipeds)
                                                         root mean
                                                         square (rms).
Level B Harassment............  Behavioral Disruption   160 dB re 1
                                 (for impulse noises).   [micro]Pa-m
                                                         (rms).
Level B Harassment............  Behavioral Disruption   120 dB re 1
                                 (for continuous,        [micro]oPa-m
                                 noise).                 (rms).
------------------------------------------------------------------------


 Table 4--Maximum Distances to MMPA Thresholds From DP Vessel Thrusters
                   During Submarine Cable Installation
------------------------------------------------------------------------
                                                           Marine mammal
                                     Marine mammal level      level B
              Source                A harassment  80/190  harassment 120
                                    dBRMS re 1 [micro]Pa    dBRMS re 1
                                             (m)          [micro]Pa  (m)
------------------------------------------------------------------------
DP Vessel Thrusters--at 10 m......  N/A.................           4,750
DP Vessel Thrusters--at 20 m......  N/A.................           4,275
DP Vessel Thrusters--at 40 m......  N/A.................           3,575
------------------------------------------------------------------------

    DWBI estimated species densities within the proposed project area 
in order to estimate the number of marine mammal exposures to sound 
levels above 120 dB (continuous noise). The data used as the basis for 
estimating species density for the project area are sightings per unit 
effort (SPUE) taken from Kenney and Vigness-Raposa (2009). 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). SPUE calculated by 
Kenney and Vigness-Raposa (2009) was derived from a number of sources 
including: (1) North Atlantic Right Whale Consortium database; (2) 
CeTAP (CeTAP, 1982); (3) sightings data from the Coastal Research and 
Education Society of Long Island, Inc. and Okeanos Ocean Research 
Foundation; (4) the Northeast Regional Stranding network (marine 
mammals); and (5) the NOAA Northeast Fisheries Science Center's 
Fisheries Sampling Branch (Woods Hole, MA).
    The Northeast Navy Operations Area (OPAREA) Density Estimates (DoN, 
2007) were also used in support for estimating take for seals, which 
represents the only available comprehensive data for seal abundance. 
However, abundance estimates for the Southern New England area includes 
breeding populations on Cape Cod, and therefore using this dataset 
alone will result in a substantial over-estimate of take in the Project 
Area. However, based on reports conducted by Kenney and Vigness-Raposa 
(2009), Schroeder (2000), and Ronald and Gots (2003),

[[Page 22228]]

harbor seal abundance off the Southern New England coast in the 
vicinity of the survey is likely to be approximately 20 percent of the 
total abundance. In addition, because the seasonality of, and habitat 
use by, gray seals roughly overlaps with harbor seals, the same 
abundance assumption of 20 percent of the southern New England 
population of gray seals can be applied when estimating abundance. Per 
this data, take due to Level B harassment for harbor seals and gray 
seals have been calculated based on 20 percent of the Northeast Navy 
OPAREA abundance estimates and resulting adjusted density values.
    The methodology for calculating takes is the same as that described 
in the Federal Register notice for the original 2014 (modified in 2015) 
BIWF IHA. Estimated takes were calculated by multiplying the maximum 
species density (per 100 km\2\) by the zone of influence (ZOI), 
multiplied by a correction factor of 1.5 to account for marine mammals 
underwater, multiplied by the number of days of the specified activity.
    A detailed description of the model used to calculate zones of 
influence is provided in the Underwater Acoustic Modeling Report found 
in Appendix A of the application. Acoustic modeling was completed with 
the U.S. Naval Research Laboratory's Range-dependent Acoustic Model 
(RAM) which is widely used by sound engineers and marine biologists due 
to its adaptability to describe highly complex acoustic scenarios. This 
modeling analysis method considers range and depth along with a geo-
referenced dataset to automatically retrieve the time of year 
information, bathymetry, and geoacoustic properties (e.g. hard rock, 
sand, mud) along propagation transects radiating from the sound source. 
Transects are run along compass points (45[deg], 90[deg], 135[deg], 
180[deg], 225[deg], 270[deg], 315[deg], and 360[deg]) to determine 
received sound levels at a given location. These values are then summed 
across frequencies to provide broadband received levels at the MMPA 
Level A and Level B harassment thresholds as described in Table 3. The 
representative area ensonified to the MMPA Level B threshold for DP 
vessel thruster use during cable installation was used to estimate 
take. The distances to the MMPA thresholds were used to conservatively 
estimate how many marine mammals would receive a specified amount of 
sound energy in a given time period and to support the development of 
monitoring and/or mitigation measures.
    DWBI used a ZOI of 9.7 mi\2\ (25.1 km\2\) and a maximum 
installation period of 28 days to estimate take from use of the DP 
vessel thruster during cable installation. The ZOI represents the 
average ensonified area across the three representative water depths 
(10 m, 20 m, and 40 m) along a 13.2-km cable route. DWBI expects cable 
installation to occur between May and October. To be conservative, take 
calculations were based on the highest seasonal species density when 
cable installation may occur (see Table 5). The resulting take 
estimates (rounded to the nearest whole number) based upon these 
conservative assumptions for North Atlantic right, humpback, fin, and 
minke whales, as well as, short-beaked common and Atlantic white-sided 
dolphins, harbor porpoise, and harbor and gray seals are presented in 
Table 5. These numbers represent less than 1.5 percent of the stock for 
these species, respectively (Table 5). These percentages are the upper 
boundary of the animal population that could be affected.

                   Table 5--DWBI's Estimated Take for DP Thruster Use During the BIWF Project
----------------------------------------------------------------------------------------------------------------
                                                                      Maximum
                                                                     seasonal                      Percentage of
                             Species                                  density        Estimated         stock
                                                                    (number/100   take  (number)    potentially
                                                                       km2)                          affected
----------------------------------------------------------------------------------------------------------------
North Atlantic Right Whale......................................            0.07               1            0.22
Humpback Whale..................................................            0.11               2            0.24
Fin Whale.......................................................            2.15              23            1.42
Minke Whale.....................................................            0.44               5            0.02
Short-beaked Common Dolphin.....................................            8.21              28            0.07
Atlantic White-sided Dolphin....................................            7.46              13            0.16
Harbor Porpoise.................................................            0.74               8            0.01
Harbor Seal.....................................................            1.95              21            0.03
Gray Seal.......................................................            2.83              30            0.01
----------------------------------------------------------------------------------------------------------------

    DWBI's requested take numbers are provided in Table 5 and this is 
also the number of takes NMFS is proposing to authorize. DWBI's take 
calculations do not take into account whether a single animal is 
harassed multiple times or whether each exposure is a different animal. 
Therefore, the numbers in Table 5 are the maximum number of animals 
that may be harassed during the cable installation activities (i.e., 
DWBI assumes that each exposure event is a different animal). These 
estimates do not account for prescribed mitigation measures that DWBI 
would implement during the specified activities and the fact that 
powerdown procedures shall be implemented if an animal enters the Level 
B harassment zone (160 dB), further reducing the potential for any 
takes to occur during these activities.
    DWBI did not request, and NMFS is not proposing, take from vessel 
strike. We do not anticipate marine mammals to be impacted by vessel 
movement because a limited number of vessels would be involved in 
construction activities and they would mostly move at slow speeds 
during DP vessel thruster use during cable installation activities. 
However, DWBI shall implement measures (e.g., vessel speed restrictions 
and separation distances; see Proposed Mitigation Measures) to further 
minimize potential impacts to marine mammals from vessel strikes during 
vessel operations and transit in the project area.

Analysis and Determinations

Negligible Impact

    Negligible impact is ``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

[[Page 22229]]

determination, as the severity of harassment may vary greatly depending 
on the context and duration of the behavioral response, many of which 
would not be expected to have deleterious impacts on the fitness of any 
individuals. In determining whether the expected takes will have a 
negligible impact, in addition to considering estimates of the number 
of marine mammals that might be ``taken,'' NMFS must consider other 
factors, such as the likely nature of any responses (their intensity, 
duration, etc.), the context of any responses (critical reproductive 
time or location, migration, etc.), as well as the number and nature of 
estimated Level A harassment takes, the number of estimated 
mortalities, and the status of the species.
    To avoid repetition, the discussion of our analyses applies to all 
the species listed in Table 5, given that the anticipated effects of 
this activity on these different marine mammal stocks are expected to 
be similar. There is no information about the nature or severity of the 
impacts, or the size, status, or structure of any of these species or 
stocks that would lead to a different analysis for this activity.
    As discussed in the Potential Effects section, permanent threshold 
shift, masking, non-auditory physical effects, and vessel strike are 
not expected to occur. There is some potential for limited TTS; 
however, animals in the area would likely incur no more than brief 
hearing impairment (i.e., TTS) due to low source levels and the fact 
that most marine mammals would more likely avoid a loud sound source 
rather than swim in such close proximity as to result in TTS. Moreover, 
as the DP vessel is continually moving along the cable route over a 24-
hour period, the area within the 120 dB isopleth is constantly moving 
(i.e., transient sound field) and shifting within a 24-hour period. 
Therefore, no single area in Rhode Island Sound will have noise levels 
above 120 dB for more than a few hours; once an area has been surveyed, 
it is not likely that it will be surveyed again, therefore reducing the 
likelihood of repeated impacts within the project area.
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see the Anticipated Effects on Habitat 
section). Marine mammal habitat may be impacted by elevated sound 
levels and some sediment disturbance, but these impacts would be 
temporary. Feeding behavior is not likely to be significantly impacted. 
Prey species are mobile, and are broadly distributed throughout the 
project area; therefore, marine mammals that may be temporarily 
displaced during survey activities are expected to be able to resume 
foraging once they have moved away from areas with disturbing levels of 
underwater noise. Because of the temporary nature of the disturbance, 
the availability of similar habitat and resources in the surrounding 
area, and the lack of important or unique marine mammal 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. There are no feeding 
areas known to be biologically important to marine mammals within the 
proposed project area.
    There are no rookeries or mating grounds known to be biologically 
important to marine mammals within the proposed project area. ESA-
listed species for which takes are proposed are North Atlantic right, 
humpback, and fin whales. Recent estimates of abundance indicate a 
stable or growing humpback whale population, while examination of the 
minimum number alive population index calculated from the individual 
sightings database for the years 1990-2010 suggests a positive and 
slowly accelerating trend in North Atlantic right whale population size 
(Waring et al., 2015). There are currently insufficient data to 
determine population trends for fin whale) (Waring et al., 2015). There 
is no designated critical habitat for any ESA-listed marine mammals 
within the project area, and none of the stocks for non-listed species 
proposed to be taken are considered ``depleted'' or ``strategic'' by 
NMFS under the MMPA.
    The proposed mitigation measures are expected to reduce the 
potential for exposure of marine mammals by reducing the DP thruster 
power if a marine mammal is observed within the 160 dB isopleth 
monitoring zone. Additional vessel strike avoidance requirements will 
further mitigate potential impacts to marine mammals during vessel 
transit in the Study Area. DWBI vessels associated with the BIWF 
construction will adhere to NMFS guidelines for marine mammal ship 
striking avoidance (available online at: https://www.nmfs.noaa.gov/pr/pdfs/education/viewing_northeast.pdf), including maintaining a distance 
of at least 1,500 feet from right whales and having dedicated protected 
species observers who will communicate with the captain to ensure that 
all measures to avoid whales are taken. NMFS believes that the size of 
right whales, their slow movements, and the amount of time they spend 
at the surface will make them extremely likely to be spotted by 
protected species observers during construction activities within the 
project area.
    DWBI did not request, and NMFS is not proposing, take of marine 
mammals by injury, serious injury, or mortality. NMFS expects that all 
takes would be in the form of short-term Level B behavioral harassment 
in the form of brief startling reaction and/or temporary vacating of 
the area, or decreased foraging (if such activity were occurring)--
reactions that are considered to be of low severity and with no lasting 
biological consequences (e.g., Southall et al., 2007). This is largely 
due to the short time scale of the proposed activities and the nature 
of the DP vessel noise (i.e., low source level, constantly moving 
resulting in a transient sound field), as well as the required 
mitigation.
    Based on best available science, NMFS preliminarily concludes that 
exposures to marine mammal species and stocks due to DWBI's DP vessel 
thruster use during cable installation activities would result in only 
short-term (temporary and short in duration) and relatively infrequent 
effects to individuals exposed, and not of the type or severity that 
would be expected to be additive for the very small portion of the 
stocks and species likely to be exposed. Given the intensity of the 
activities, and the fact that shipping contributes to the ambient sound 
levels in the surrounding waters, NMFS does not anticipate the proposed 
take estimates to impact annual rates of recruitment or survival. 
Animals may temporarily avoid the immediate area, but are not expected 
to permanently abandon the area. Major shifts in habitat use, 
distribution, or foraging success, are not expected.
    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 DWBI's DP vessel thruster use during cable 
installation activities will have a negligible impact on the affected 
marine mammal species or stocks.

Small Numbers

    The requested takes proposed to be authorized for the cable 
installation activities utilizing DP vessel thrusters represent 0.22 
percent of the Western North Atlantic (WNA) stock of North Atlantic 
right whale, 0.24 percent of the Gulf of Maine stock of humpback whale, 
1.42 percent of the WNA stock of fin whale, 0.02 percent of the 
Canadian East

[[Page 22230]]

Coast stock of minke whale, 0.07 percent of the WNA stock of short-
beaked common dolphin, 0.16 percent of the WNA stock of Atlantic white-
sided dolphin, 0.01 percent of the Gulf of Maine/Bay of Fundy stock of 
harbor porpoise, 0.03 percent of the WNA stock of harbor seal, and 0.01 
percent of the North Atlantic stock of gray seal. These take estimates 
represent the percentage of each species or stock that could be taken 
by Level B behavioral harassment and represent extremely small numbers 
(less than 1.5 percent) relative to the affected species or stock 
sizes. Further, the proposed take numbers are the maximum numbers of 
animals that are expected to be harassed during the project; it is 
possible that some of these exposures may occur to the same individual. 
Therefore, NMFS preliminarily finds that small numbers of marine 
mammals will be taken relative to the populations of the affected 
species or stocks.

Impact on Availability of Affected Species for Taking for Subsistence 
Uses

    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

    There are three marine mammal species that are listed as endangered 
under the ESA: Fin whale, humpback whale, and North Atlantic right 
whale. Under section 7 of the ESA, the U.S. Army Corps of Engineers 
(the federal permitting agency for the actual construction) consulted 
with NMFS on the proposed BIWF project. NMFS also consulted internally 
on the issuance of an IHA under section 101(a)(5)(D) of the MMPA for 
this activity. NMFS' Greater Atlantic Regional Fisheries Office (GARFO) 
issued a Biological Opinion on January 30, 2014 which was amended on 
June 5, 2015, concluding that the Block Island Wind Farm project may 
adversely affect but is not likely to jeopardize the continued 
existence of fin whale, humpback whale, or North Atlantic right whale.

National Environmental Policy Act

    NMFS conducted the required analysis under NEPA and prepared an EA 
for its issuance of the original BIWF IHA, issuing a Finding of No 
Significant Impact (FONSI) for the action on August 21, 2014 
(reaffirmed on June 9, 2015). The potential environmental impacts of 
the proposed IHA are within the scope of the environmental impacts 
analyzed in the NMFS' EA, which was used to support NMFS' FONSI. NMFS 
has determined that there are no substantial changes to the action and 
that there are no new direct, indirect, or cumulative effects to the 
human environment resulting from the IHA modifications. Therefore, NMFS 
has determined that a new or supplemental EA or Environmental Impact 
Statement are unnecessary, and reaffirms the existing FONSI for this 
action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an Incidental Harassment Authorization (IHA) to DWBI for cable 
installation activities that use DP vessel thrusters from May 2016 
through April 2017, provided the previously mentioned mitigation, 
monitoring, and reporting requirements are incorporated. The proposed 
IHA language is provided next.
    This section contains a draft of the IHA itself. The wording 
contained in this section is proposed for inclusion in the IHA (if 
issued).
    Deepwater Wind Block Island, LLC, 56 Exchange Terrace, Suite 101, 
Providence, RI, 02903-1772, is hereby authorized under section 
101(a)(5)(D) of the Marine Mammal Protection Act (16 U.S.C. 
1371(a)(5)(D)) and 50 CFR 216.107, to harass marine mammals incidental 
to dynamic positioning vessel thruster use associated with inter-array 
and export cable installation activities off the southeast coast of 
Block Island, Rhode Island.
    1. This Authorization is valid from May 1, 2016 through April 30, 
2017.
    2. This Authorization is valid only for DP vessel thruster use 
associated with cable installation activities, as described in the IHA 
application.
    3. The holder of this authorization (Holder) is hereby authorized 
to take, by Level B harassment only, 13 Atlantic white-sided dolphins 
(Lagenorhynchus acutus), 28 short-beaked common dolphins (Delphinus 
delphis), 8 harbor porpoises (Phocoena phocoena), 2 minke whales 
(Balaenoptera acutorostrata), 23 fin whales (Balaenoptera physalus), 2 
humpback whales (Megaptera novaeangliae), 1 North Atlantic right whales 
(Eubalaena glacialis), 30 gray seals (Halichoerus grypus), and 21 
harbor seals (Phoca vitulina) incidental to the Block Island Wind Farm 
inter-array and export cable installation activities using dynamic 
positioning (DP) vessel thrusters.
    4. The taking of any marine mammal in a manner prohibited under 
this IHA must be reported immediately to NMFS' Greater Atlantic 
Regional Fisheries Office (GARFO), 55 Great Republic Drive, Gloucester, 
MA 01930-2276; phone 978-281-9300, and NMFS' Office of Protected 
Resources, 1315 East-West Highway, Silver Spring, MD 20910; phone 301-
427-8401.
    5. The Holder or designees must notify NMFS' GARFO and Office of 
Protected Resources (Headquarters) at least 24 hours prior to the 
seasonal commencement of the specified activity (see contact 
information in 4 above).
    6. The holder of this Authorization must notify the Chief of the 
Permits and Conservation Division, Office of Protected Resources, or 
her designee at least 24 hours prior to the start of survey activities 
(unless constrained by the date of issuance of this Authorization in 
which case notification shall be made as soon as possible) at 301-427-
8401 or to John.Fiorentino@noaa.gov.

7. Mitigation Requirements

    The Holder is required to abide by the following mitigation 
conditions listed in 7(a)-(c). Failure to comply with these conditions 
may result in the modification, suspension, or revocation of this IHA.
    (a) DP Thruster Power Reduction--During cable installation, if 
marine mammals enter or approach the established 160 dB isopleth 
monitoring zone, DWBI shall reduce DP thruster to the maximum extent 
possible, except under circumstances when reducing DP thruster use 
would compromise safety (both human health and environmental) and/or 
the integrity of the Project. After decreasing thruster energy, 
protected species observers (PSOs) will continue to monitor marine 
mammal behavior and determine if the animal(s) is moving towards or 
away from the established monitoring zone. If the animal(s) continues 
to move towards the sound source then DP thruster use would remain at 
the reduced level. Normal thruster use will resume when PSOs report 
that marine mammals have moved away from and remained clear of the 
monitoring zone for a minimum of 30 minutes since last the sighting.
    (b) Vessel Speed Restrictions: All project vessels shall operate at 
speeds of 10 knots or less from November 1 through April 30.
    (c) Ship Strike Avoidance: The Holder shall adhere to NMFS 
guidelines for marine mammal ship strike avoidance (https://www.nmfs.noaa.gov/pr/pdfs/education/viewing_northeast.pdf).

8. Monitoring Requirements

    The Holder is required to abide by the following monitoring 
conditions listed in 8(a)-(b). Failure to comply with these conditions 
may result in the

[[Page 22231]]

modification, suspension, or revocation of this IHA.
    (a) Visual Monitoring--Visual observation of the 160-dB monitoring 
zone will be performed by qualified and NMFS approved protected species 
observers (PSOs). Observer qualifications will include direct field 
experience on a marine mammal observation vessel and/or aerial surveys 
in the Atlantic Ocean/Gulf of Mexico. A minimum of two PSOs will be 
stationed aboard the DP vessel. Each PSO will monitor 360 degrees of 
the field of vision. PSOs stationed on the DP vessel will begin 
observation of the monitoring zone as the vessel initially leaves the 
dock. Observations of the monitoring zone will continue throughout the 
cable installation and will end after the DP vessel has returned to 
dock. Observers would estimate distances to marine mammals visually, 
using laser range finders, or by using reticle binoculars during 
daylight hours. During night operations, night vision binoculars will 
be used. Position data will be recorded using hand-held or vessel 
global positioning system (GPS) units for each sighting, vessel 
position change, and any environmental change. Each PSO stationed on 
the cable lay vessel will scan the surrounding area for visual 
indication of marine mammal presence that may enter the monitoring 
zone. Observations will take place from the highest available vantage 
point on the cable lay vessel. General 360-degree scanning will occur 
during the monitoring periods, and target scanning by the PSO will 
occur when alerted of a marine mammal presence. Information recorded 
during each observation shall be used to estimate numbers of animals 
potentially taken and shall include the following:
     Dates and locations of construction operations;
     Number of observations;
     Time and frequency of observations;
     Location (i.e., distance from sound source);
     DP vessel thruster status (i.e., energy level)
     Weather conditions;
     Details of mammal sightings (species, age classification 
[if known], numbers)
     Reaction of the animal(s) to relevant sound source (if 
any) and observed behavior, including bearing and direction of travel; 
and
     Details of any observed ``taking'' (behavioral 
disturbances or injury/mortality;
    All marine mammal sightings which are visually feasible beyond the 
160 dB isopleth, shall also be recorded and potential takes shall be 
noted.
    (b) Acoustic Field Verification--DWBI would perform field 
verification to confirm the 160-dB isopleth monitoring zone. Field 
verification during cable installation using DP thrusters will be 
performed using acoustic measurements from two reference locations at 
two water depths (a depth at mid-water and a depth at approximately 1 m 
above the seafloor). As necessary, the monitoring zone will be modified 
to ensure adequate protection to marine mammals.

9. Reporting Requirements

    (a) The Holder shall provide the following notifications during 
construction activities:
     Notification to NMFS and the U.S. Army Corps of Engineers 
(USACE) within 24-hours of beginning construction activities and again 
within 24-hours of completion
     The USACE and NMFS shall be notified within 24 hours 
whenever a monitoring zone is re-established by DWBI. After any re-
establishment of the monitoring zone, DWBI will provide a report to the 
USACE and NMFS detailing the field-verification measurements within 7 
days. This shall include the following information: a detailed account 
of the levels, durations, and spectral characteristics of DP thruster 
use, and the peak, RMS, and energy levels of the sound pulses and their 
durations as a function of distance, water depth, and tidal cycle. The 
USACE and NMFS will be notified within 24 hours if field verification 
measurements suggest a larger DP thruster power reduction zone. 
Implementation of a smaller zone shall be contingent on NMFS' review 
and shall not be used until NMFS approves the change.
     Notification of Injured or Dead Marine Mammals--In the 
unanticipated event that the specified activities clearly causes the 
take of a marine mammal in a manner prohibited by the IHA, such as a 
serious injury, or mortality (e.g., ship-strike, gear interaction, and/
or entanglement), DWBI 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 NOAA Greater Atlantic 
Regional Fisheries Office (GARFO) Stranding Coordinator. The report 
would include the following information:
    [cir] Time, date, and location (latitude/longitude) of the 
incident;
    [cir] Name and type of vessel involved;
    [cir] Vessel's speed during and leading up to the incident;
    [cir] Description of the incident;
    [cir] Status of all sound source use in the 24 hours preceding the 
incident;
    [cir] Water depth;
    [cir] Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    [cir] Description of all marine mammal observations in the 24 hours 
preceding the incident;
    [cir] Species identification or description of the animal(s) 
involved;
    [cir] Fate of the animal(s); and
    [cir] 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 DWBI to minimize 
reoccurrence of such an event in the future. DWBI would not resume 
activities until notified by NMFS.
    In the event that DWBI 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), DWBI would immediately report the incident to the Chief 
of the Permits and Conservation Division, Office of Protected Resources 
and the GARFO 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 the Applicant to determine if modifications in the 
activities are appropriate.
    In the event that DWBI 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), DWBI would report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the NMFS Greater Atlantic Regional Fisheries Office Regional 
Stranding Coordinator, within 24 hours of the discovery. DWBI would 
provide photographs or video footage (if available) or other 
documentation of the stranded animal sighting to NMFS. DWBI can 
continue its operations under such a case.
    (b) The Holder shall provide a final technical report to USACE and 
NMFS, within 120 days after completion of the construction activities, 
that fully documents the methods and monitoring protocols, summarizes 
the data recorded during monitoring, estimates the number of marine 
mammals that may

[[Page 22232]]

have been taken during construction activities, and provides an 
interpretation of the results and effectiveness of all monitoring 
tasks. The report shall contain the following information:
     A summary of the activity and monitoring plan (i.e., 
dates, times, locations);
     A summary of mitigation implementation;
     Monitoring results and a summary that addresses the goals 
of the monitoring plan, including the following:
    [cir] Environmental conditions when observations were made:
    [cir] Water conditions (i.e., Beaufort sea-state, tidal state)
    [cir] Weather conditions (i.e., percent cloud cover, visibility, 
percent glare)
    [cir] Date and time survey initiated and terminated
    [cir] Date, time, number, species, age, and any other relevant data 
regarding marine mammals observed
    [cir] Description of the observed behaviors (in both the presence 
and absence of activities):
    [ssquf] If possible, the correlation to underwater sound level 
occurring at the time of any observable behavior
     Estimated exposure/take numbers during activities; and
     An assessment of the implementation and effectiveness of 
prescribed mitigation and monitoring measures.
    10. This Authorization may be modified, suspended, or withdrawn if 
the Holder fails to abide by the conditions prescribed herein or if the 
authorized taking is having more than a negligible impact on the 
species or stock of affected marine mammals, or if there is an 
unmitigable adverse impact on the availability of such species or 
stocks for subsistence uses.
    11. A copy of this Authorization and the Incidental Take Statement 
must be in the possession of each vessel operator taking marine mammals 
under the authority of this Incidental Harassment Authorization.
    12. The Holder is required to comply with the Terms and Conditions 
of the Incidental Take Statement corresponding to NMFS' Biological 
Opinion.

Request for Public Comments

    NMFS requests comment on our analysis, the draft authorization, and 
any other aspect of the Notice of Proposed IHA for DWBI's proposed 
dynamic positioning vessel thruster use associated with inter-array and 
export cable installation activities off the southeast coast of Block 
Island, Rhode Island. Please include with your comments any supporting 
data or literature citations to help inform our final decision on 
DWBI's request for an MMPA authorization.

    Dated: April 11, 2016.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2016-08729 Filed 4-14-16; 8:45 am]
 BILLING CODE 3510-22-P