Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel Project in Virginia Beach, Virginia, 18777-18801 [2018-09032]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 83, Number 83 (Monday, April 30, 2018)]
[Notices]
[Pages 18777-18801]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-09032]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG107


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel 
Project in Virginia Beach, Virginia

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

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

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SUMMARY: NMFS has received a request from the Chesapeake Tunnel Joint 
Venture (CTJV) for authorization to take marine mammals incidental to 
the Parallel Thimble Shoal Tunnel Project (PTST) in Virginia Beach, 
Virginia. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is 
requesting comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS will consider public comments prior to 
making any final decision on the issuance of the requested MMPA 
authorizations and agency responses will be summarized in the final 
notice of our decision.

DATES: Comments and information must be received no later than May 30, 
2018.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at https://www.fisheries.noaa.gov/node/23111 without change. All personal 
identifying information (e.g., name, address) voluntarily submitted by 
the commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Rob Pauline, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce (as delegated to NMFS) to allow, upon 
request, the incidental, but not intentional, taking of small numbers 
of marine mammals by United States. 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.
    The MMPA states that the term ``take'' means to harass, hunt, 
capture, kill or attempt to harass, hunt, capture, or kill any marine 
mammal.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild (Level A harassment); or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering (Level B harassment).

National Environmental Policy Act

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

[[Page 18778]]

issuance of the proposed IHA qualifies to be categorically excluded 
from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On January 11, 2018, NMFS received a request from the CTJV for an 
IHA to take marine mammals incidental to pile driving at the Chesapeake 
Bay Bridge and Tunnel (CBBT) near Virginia Beach, Virginia. CTJV's 
request is for take of small numbers of harbor seal (Phoca vitulina), 
gray seal (Halichoerus grypus), bottlenose dolphin (Tursiops spp.), 
harbor porpoise (Phocoena phocoena), and humpback whale (Megaptera 
novaeangliae) by Level A and Level B harassment. Neither the CTJV nor 
NMFS expect serious injury or mortality to result from this activity 
and, therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    The PTST project consists of the construction of a two-lane 
parallel tunnel to the west of the existing Thimble Shoal Tunnel, 
connecting Portal Island Nos. 1 and 2 (Figure 1 in application). Upon 
completion, the new tunnel will carry two lanes of southbound traffic 
and the existing tunnel will remain in operation and carry two lanes of 
northbound traffic. The PTST project will address existing constraints 
to regional mobility based on current traffic volume along the 
Chesapeake Bay Bridge-Tunnel (CBBT) facility; improve safety by 
minimizing one lane, two-way traffic in the tunnel; improve the ability 
to conduct necessary maintenance with minimal impact to traffic flow; 
and ensure a reliable southwest hurricane evacuation route for 
residents of the eastern shore and/or a northern evacuation route for 
residents of the eastern shore, Norfolk, and Virginia Beach. The CBBT 
is a 23 mile fixed link crossing the mouth of the Chesapeake Bay which 
connects Northampton County on the Delmarva Peninsula with Virginia 
Beach, which is part of the Hampton Roads metropolitan area.
    The new parallel tunnel will be bored under the Thimble Shoal 
Channel. The 6,525 linear feet (ft) of new tunnel will be constructed 
with a top of tunnel depth/elevation of 100 ft below Mean Low Water 
(MLW) within the width of the 1,000-ft-wide navigation channel. Impact 
pile driving will be used to install steel piles and vibratory pile 
driving will be utilized to install sheet piles. Sound produced during 
pile driving activities may result in behavioral harassment or auditory 
injury to local marine mammals. In-water construction will occur during 
spring and summer of 2018. This proposed IHA would cover one year of a 
larger project for which will run through 2022. The larger project, 
which does not employ pile driving and does not require an IHA, 
involves tunnel excavation with a tunnel boring machine and 
construction of a roadway within the tunnel.

Dates and Duration

    In-water construction is planned to begin on June 1, 2018 and run 
through March 31, 2019. Pile driving, which may be concurrent at times, 
could occur up to 8 hours per day for up to 202 days.

Specific Geographic Region

    The PTST project is located between Portal Island Nos. 1 and 2 of 
the CBBT, and will be bored underneath the Thimble Shoal Channel in the 
Chesapeake Bay. Water depths within the PTST construction area range 
from 0 to 60 ft below Mean Lower Low Water (MLLW). The Thimble Shoal 
Channel is 1,000 ft wide, is authorized to a depth of 55 ft below MLLW, 
and is maintained at a depth of 50 ft MLLW.

Detailed Description of Specific Activity

    Construction of the tunnel structure will begin on Portal Island 
No. 1 and move from south to north to Portal Island No. 2. It is 
anticipated that this project will be constructed without any or 
minimal effect on the existing tunnel and traffic operations. The only 
short-term possibility for traffic impact could occur when connecting 
the existing roadway to the new roadway. The Tunnel Boring Machine 
(TBM) components will be barged and trucked to Portal Island No. 1. The 
TBM will be assembled within an entry/launch portal that will be 
constructed on Portal Island No. 1. The machine will then both excavate 
material and construct the tunnel as it progresses from Portal Island 
No. 1 to Portal Island No. 2. Material excavated from within the tunnel 
will be transported via a conveyor belt system back to Portal Island No 
1. Approximately 350,000 cubic yards (cy) (in situ volume) of material 
will be excavated by the TBM and 524,000 cy (bulked volume) will be 
conveyed to Portal Island No. 1. This material will be transported 
offsite using a combination of trucks and barges and will be disposed 
at an approved off-site, upland facility in accordance with the Dredged 
Material Management Plan.
    Precast concrete tunnel segments will be transported to the TBM for 
installation. The TBM will assemble the tunnel segments in-place as the 
tunnel is bored. After the TBM reaches Portal Island No. 2, it will be 
disassembled and the components will be removed via an exit/receiving 
portal on Portal Island No. 2. After the tunnel structure is completed, 
final upland work for the PTST project will include installation of the 
final roadway, lighting, finishes, mechanical systems, and other 
required internal systems for tunnel use and function. In addition, the 
existing fishing pier will be repaired and refurbished.
    In-Water Construction Activities. In-water activities for the 
tunnel construction will be limited to eight primary actions:
    (1) Construction and use of a temporary dock, an integrated 
temporary conveyor dock, and mooring facilities;
    (2) Construction of temporary roadway trestles requiring a limited 
number of in-water piles and partially extending over water to 
facilitate safe construction vehicle movements on each portal island. 
For Portal Island No. 1, the temporary docking will integrate the 
roadway trestle in the same structure;
    (3) Construction of temporary work trestles approximately 850 ft 
long and 35 ft wide each, and offset west of the tunnel alignment to 
facilitate construction of the berms;
    (4) Temporary subaqueous stockpiling of existing armor stones for 
re-use;
    (5) Construction of two permanent engineered berms (one extending 
channelward from each of the two portal islands) including installation 
of steel sheet pile to provide settlement mitigation between the 
existing tunnel and the new tunnel, handling of existing stone, adding 
new stone, and limited mechanical dredging at Portal Island No. 1;
    (6) Underground (below the sediment-water interface) tunnel boring;
    (7) Repair/rehabilitation to the existing fishing pier substructure 
and trestle substructure (only if deemed necessary based on 
inspection); and
    (8) Construction and use of outfalls on the east side of Portal 
Island No. 1 to allow for permitted process water discharges from a 
project-specific wastewater treatment facility, and periodic, 
intermittent warm water discharges of non-contact cooling water from an 
on-site cooling system.
    Up to 132 hollow steel piles measuring 36 inches in diameter will 
be installed to support the integrated temporary dock/barge unloading/

[[Page 18779]]

conveyor facility and temporary conveyor dock at Portal Island No. 1. 
Of these, 82 will be placed in-water and 50 will be placed upland 
(above the mean high water (MHW) line). Up to 30 hollow steel piles 
(36-inch diameter) will be installed to provide mooring facilities 
along each portal island (six dolphin moorings comprised of five piles 
each).
    Up to 160 hollow steel piles (36-inch in diameter, below MHW) will 
be installed to support temporary work platforms (trestles) offset to 
the west of each of the two engineered berms. These trestles will 
extend 841 ft and 809 ft channelward from Portal Island Nos. 1 and 2, 
respectively. Up to 12 round piles will be installed on the island 
above MHW to support a temporary roadway trestle at Portal Island No. 
2. Installation for the temporary docks and mooring dolphins will occur 
over approximately 2 months; commencing in June 2018 as shown in Table 
1. Installation of the temporary offset construction trestles will 
occur over approximately five months. In-water pile driving activities 
will also include installation of sheet pile for settlement mitigation 
and as an in-water containment system to facilitate construction of the 
engineered berms adjacent to Portal Island Nos. 1 and 2. A total of 
1,540 linear ft of sheet pile (or 830 individual sheets each 27.56 
inches in length) will be installed over approximately eight months.

                                 Table 1--Anticipated Pile Installation Schedule
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                                                                                                   Anticipated
        Pile location            Pile function       Pile type     Number of piles (upland/in-    installation
                                                                              water)                  date
----------------------------------------------------------------------------------------------------------------
Portal Island Nos. 1 and 2...  Mooring dolphins  36-inch diameter  30.........................  1 June to 30
                                (in-water).       hollow steel.                                  June 2018.
West of Portal Island No. 1..  Berm              36-inch diameter  80.........................  1 July 2018
                                construction      hollow steel.                                  through 1
                                trestle (in-                                                     January 2019.
                                water).
West of Portal Island No. 2..  Berm              36-inch diameter  80.........................  1 July 2018
                                construction      hollow steel.                                  through 1
                                trestle (in-                                                     January 2019.
                                water).
Portal Island No. 1..........  Temporary docks   36-inch diameter  50.........................  1 May 2018
                                (upland).         hollow.                                        through 30 June
                                                 steel...........                                2018.
Portal Island No. 1..........  Temporary docks   36-inch diameter  82.........................  1 July 2018 to
                                (in- water).      hollow steel.                                  30 August 2018.
Portal Island No. 2 (above     Temporary         36-inch diameter  12.........................  1 May to 31 May
 MHW).                          roadway trestle   hollow steel.                                  2018.
                                (upland).
Portal Island No. 1 (above     Excavated TBM     28 and 18-inch    1,110......................  1 May 2018 to 30
 MHW).                          material          steel sheet.                                   September 2018.
                                containment
                                holding (muck)
                                bin (upland).
Portal Island Nos. 1 and 2     Settlement        28-inch steel     2,554......................  1 August 2018 to
 (above and below MHW).         mitigation and    sheet.                                         30 March 2019.
                                flowable fill
                                containment.
Portal Island Nos. 1 and 2     Portal            Steel sheet.....  1,401......................  1 June 2018 to
 (above MHW).                   excavation.                                                      30 September
                                                                                                 2018, 1 January
                                                                                                 to 30 March
                                                                                                 2019.
Portal Island Nos. 1 and 2     Excavation        Steel sheet.....  240........................  1 April 2018 to
 (above MHW).                   Support.                                                         30 August 2019
                                                                                                 to 1 January
                                                                                                 2019 to 30
                                                                                                 March 2019.
                                                                  -----------------------------
    Total (above and below     ................  ................  5,305 Sheet Piles; 334
     water).                                                        Round Piles.
----------------------------------------------------------------------------------------------------------------

    Prior to initiation of the boring of the tunnel, construction of 
two engineered in-water berms will be required to provide structural 
support to the launch/receiving sections of the tunnel that are in 
closest proximity to the portal islands. Each engineered berm (at its 
maximum design configuration) will extend from the portal island 
channelward and will be approximately 1,400 ft long by 260 ft wide (at 
its widest point). Construction of the engineered berms will require 
installation of temporary trestles offset to the west of each berm 
alignment to serve as work platforms. The trestles will be supported by 
36-inch diameter round steel piles driven by an impact hammer (with an 
encased bubble curtain). Construction will also require installation of 
parallel rows of sheet pile (using a vibratory hammer) approximately 
530 linear ft in length by 60 ft in width channelward from MHW along 
the berm alignment at both Portal Islands.
    Mechanical dredging to remove unsuitable berm foundation material 
(Portal Island No. 1 only) and disposal of dredged material via bottom-
dump, or upland placement at an approved site. Note that NMFS does not 
consider underwater noise levels associated with dredging to occur at a 
level that could result in harassment of marine mammals. Therefore, 
dredging operations are not considered further in this analysis.
    A number of additional upland construction activities are planned 
on the Portal Islands as part of the PTST project. Since these 
activities will not occur in water, they are not included as part of 
this analysis and are described in detail in section 1.3 in the 
application.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see ``Proposed 
Mitigation'' and ``Proposed Monitoring and Reporting'').

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SAR; www.nmfs.noaa.gov/pr/sars/) and more general information about these species (e.g., physical 
and behavioral descriptions) may be found on NMFS's website 
(www.nmfs.noaa.gov/pr/species/mammals/).
    Table 2 lists all species with expected potential for occurrence in 
near the CBBT and summarizes information

[[Page 18780]]

related to the population or stock, including regulatory status under 
the MMPA and ESA and potential biological removal (PBR), where known. 
For taxonomy, we follow Committee on Taxonomy (2016). PBR is defined by 
the MMPA as the maximum number of animals, not including natural 
mortalities, that may be removed from a marine mammal stock while 
allowing that stock to reach or maintain its optimum sustainable 
population (as described in NMFS's SARs). While no mortality is 
anticipated or authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond United States waters. All managed stocks in this region are 
assessed in NMFS's United States Atlantic and Gulf of Mexico Marine 
Mammal Stock Assessments (Hayes et al., 2017a,b). All values presented 
in Table 2 are the most recent available at the time of publication and 
are available in the 2016 Stock Assessment Report (Hayes et al., 2017a) 
and draft 2017 stock assessment report (Hayes et al., 2017b) (available 
online at: www.nmfs.noaa.gov/pr/sars/regiont.htm).

                                          Table 2--Marine Mammal Species Likely To Occur Near the Project Area
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                                                                                         ESA/MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock            Strategic (Y/N)      Nmin, most recent       PBR      Annual M/
                                                                                               \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenidae:
    North Atlantic Right whale......  Eubalaena glacialis....  Western North Atlantic   E/D; Y             458 (0; 455; 2017)....        1.4          36
                                                                (WNA).
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Family Balaenopteridae (rorquals):
    Humpback whale..................  Megaptera novaeangliae.  Gulf of Maine..........  -; N               335 (.42; 239; 2012)..        3.7         8.5
    Fin whale.......................  Balaenoptera physalus..  WNA....................  E/D; Y             1,618 (0.33; 1,234;           2.5        2.65
                                                                                                            2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Bottlenose dolphin..............  Tursiops spp...........  WNA Coastal, Northern    D; Y               11,548 (0.36; 8,620;           86     1.0-7.5
                                                                Migratory.                                  2010-11).
                                                               WNA Coastal, Southern    D; Y               9,173 (0.46; 6,326;            63        0-12
                                                                Migratory.                                  2010-11).
                                                               Northern North Carolina  D; S               823 (0.06; 782; 2013).        7.8    1.0-16.7
                                                                Estuarine System.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Gulf of Maine/Bay of     -; N               79,833 (0.32; 61,415;         706  307 (0.16)
                                                                Fundy.                                      2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  WNA....................  -; N               75,834 (0.1; 66,884,        2,006         368
                                                                                                            2012).
    Gray seal.......................  Halichoerus grypus.....  WNA....................  -; N               27,131 (.1, 25,908,         1,554       5,207
                                                                                                            2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
Note--Italicized species are not expected to be taken or proposed for authorization.

    All species that could potentially occur in the proposed survey 
areas are included in Table 2. However, the occurrence of endangered 
North Atlantic right whales and endangered fin whales is such that take 
is not expected to occur, and they are not discussed further beyond the 
explanation provided here. Between 1998 and 2013, there were no reports 
of North Atlantic right whale strandings within the Chesapeake Bay and 
only four reported standings along the coast of Virginia. During this 
same period, only six fin whale strandings were recorded within the 
Chesapeake Bay (Barco and Swingle 2014). In 2016, there were no reports 
of fin whale strandings (Barco et al., 2017). Due to the low occurrence 
of North Atlantic right whales and fin whales, NMFS is not proposing 
take of these species.

Humpback Whale

    Humpback whales inhabit all major ocean basins from the equator to 
subpolar latitudes. They generally follow a predictable migratory 
pattern in both hemispheres, feeding during the summer in the higher 
latitudes (40 to 70 degrees latitude) and migrating to lower latitudes 
(10 to 30 degrees latitude) where calving and breeding take place in 
the winter (Perry et al., 1999, NOAA

[[Page 18781]]

Fisheries 2006a). During the spring, summer, and fall, humpback whales 
in the North Atlantic Ocean feed over a range that includes the eastern 
coast of the United States, the Gulf of St. Lawrence, Newfoundland/
Labrador, and western Greenland.
    Humpback whales are the whale most likely to occur in the project 
area and could be found there at any time of the year. NOAA reported 
that between 2009-2013, three humpback whales were stranded in Virginia 
in the lower Bay (one off of Northampton County, one near the York 
River, and one off of Ft. Story), and two were stranded in Maryland 
near Ocean City (NOAA Fisheries 2015b). All of the whales stranded in 
Virginia and Maryland had signs of human-caused injury. NOAA's database 
of mortality and serious injury indicates no human caused serious 
injuries for humpback whales in the Chesapeake Bay proper between 1999 
and 2003. The only reported mortality of a humpback whale during the 
1999-2003 time period was at the mouth of the Chesapeake Bay in 
Virginia as the result of a ship strike. Three other humpback whale 
mortalities related to ship strikes or entanglement in fishing gear in 
Virginia waters were reported during the study period. One serious 
injury to a humpback whale as a result of entanglement in fishing gear 
occurred near Ocean City, Maryland (Cole et al., 2005).
    There have been 33 humpback whale strandings recorded in Virginia 
between 1988 and 2013; 11 had signs of entanglement and 9 had injuries 
from vessel strikes. Most of these strandings were reported from ocean 
facing beaches, but 11 were also within the Chesapeake Bay (Barco and 
Swingle 2014). Strandings occurred in all seasons, but were most common 
in the spring. In the past 5 years of reported data (2011-2015), there 
have been five humpback whale strandings in Virginia (Swingle et al., 
2012, Swingle et al., 2013, Swingle et al., 2014, Swingle et al., 2015, 
Swingle et al., 2016). Since the beginning of 2017, five dead humpback 
whales have been observed in Virginia (Funk 2017). Ship strikes have 
been attributed as the likely cause of death in these instances. Note 
that in 2016, NMFS declared that an Unusual Mortality Event (UME) for 
humpback whales strandings along the Atlantic Coast from Maine through 
North Carolina. This means that elevated whale mortalities have 
occurred in the area. Since January 2016 through March 2018, thirteen 
strandings have occurred in Virginia and two have occurred in Maryland.
    In winter, whales from the six feeding areas mate and calve 
primarily in the West Indies where spatial and genetic mixing among 
these groups occur (Waring et al., 2000). Various papers (Clapham and 
Mayo 1990, Clapham et al., 1992, Barlow and Clapham 1997, Clapham et 
al., 1999) summarized information gathered from a catalogue of 
photographs of 643 individuals from the western North Atlantic 
population of humpback whales (also referred to as the Gulf of Maine 
stock). These photographs identified reproductively mature western 
North Atlantic humpbacks wintering in tropical breeding grounds in the 
Antilles, primarily on Silver and Navidad Banks, north of the Dominican 
Republic. The primary winter range also includes the Virgin Islands and 
Puerto Rico (NOAA Fisheries 1991). Not all whales migrate to the West 
Indies every year and some are found in the mid- and high-latitude 
regions during the winter months.
    Humpback whales use the mid-Atlantic as a migratory pathway to and 
from the calving/mating grounds, but it may also be an important winter 
feeding area for juveniles. Since 1989, observations of juvenile 
humpbacks in the mid-Atlantic have been increasing during the winter 
months, peaking from January through March (Swingle et al., 1993). 
Biologists theorize that non-reproductive animals may be establishing a 
winter feeding range in the mid-Atlantic since they are not 
participating in reproductive behavior in the Caribbean. Swingle et al. 
(1993) identified a shift in distribution of juvenile humpback whales 
in the nearshore waters of Virginia, primarily in winter months. 
Identified whales using the mid-Atlantic area were found to be 
residents of the Gulf of Maine and Atlantic Canada (Gulf of St. 
Lawrence and Newfoundland) feeding groups; suggesting a mixing of 
different feeding populations in the Mid-Atlantic region. Strandings of 
humpback whales have increased between New Jersey and Florida since 
1985, consistent with the increase in mid-Atlantic whale sightings. 
Strandings were most frequent during September through April in North 
Carolina and Virginia waters, and were composed primarily of juvenile 
humpback whales of no more than 11 meters in length (Wiley et al., 
1995).

Bottlenose Dolphin

    Bottlenose dolphins occur in temperate and tropical oceans 
throughout the world, ranging in latitudes from 45[deg] N to 45[deg] S 
(Blaylock 1985). In the western Atlantic Ocean there are two distinct 
morphotypes of bottlenose dolphins, an offshore type that occurs along 
the edge of the continental shelf as well as an inshore type. The 
inshore morphotype can be found along the entire United States coast 
from New York to the Gulf of Mexico, and typically occurs in waters 
less than 20 meters deep (NOAA Fisheries 2016a). There is evidence that 
the inshore bottlenose dolphins may be made up of seven different stock 
which may be either year-round residents or migratory. Bottlenose 
dolphins found in Virginia are representative primarily of either the 
northern migratory coastal stock or southern migratory coastal stock. 
The northern migratory stock spends the winter along the coast of North 
Carolina and migrates as far north as Long Island, New York in the 
summer. They are rarely found north of North Carolina in the winter 
(NOAA Fisheries 2016a). During October-December, the southern migratory 
stock occupies waters of southern North Carolina. During January-March, 
the southern migratory stock appears to move as far south as northern 
Florida. During April-June, the stock moves north to North Carolina 
while during July-August, the stock is presumed to occupy coastal 
waters north of Cape Lookout, North Carolina, to the eastern shore of 
Virginia. It is possible that these animals also occur inside the 
Chesapeake Bay and in nearshore coastal waters. There is also evidence 
that limited numbers of the Northern North Carolina Estuarine System 
Stock (NNCES) may occur in the Chesapeake Bay in the July-August 
timeframe.
    Bottlenose dolphins are the most abundant marine mammal along the 
Virginia coast and within the Chesapeake Bay. They are seen annually in 
Virginia from May through October with around 65 strandings occurring 
each year (Barco and Swingle 2014). During 2016, 68 bottlenose dolphin 
strandings were recorded in Virginia (Barco et al., 2017). Stranded 
bottlenose dolphins have been recorded as far north as the Potomac 
River in the Chesapeake Bay (Blaylock 1985). Both the northern and 
southern migratory coastal stocks are listed as depleted under the 
MMPA.
    The inshore variety of bottlenose dolphins often travel in small 
groups of 2 to 15 individuals. These groups and will travel into bays, 
estuaries, and rivers to feed, utilizing echolocation to find a variety 
of prey, including fish, squid, and benthic invertebrates (NOAA 
Fisheries 2017b).

Harbor Porpoise

    The harbor porpoise is typically found in colder waters in the 
northern

[[Page 18782]]

hemisphere. In the western North Atlantic Ocean, harbor porpoises range 
from Greenland to as far south as North Carolina (Barco and Swingle 
2014). They are commonly found in bays, estuaries, and harbors less 
than 200 meters deep (NOAA Fisheries 2017c). Harbor porpoises in the 
United States are made up of the Gulf of Main/Bay of Fundy stock. Gulf 
of Main/Bay of Fundy stock are concentrated in the Gulf of Maine in the 
summer, but are widely dispersed from Maine to New Jersey in the 
winter. South of New Jersey, harbor porpoises occur at lower densities. 
Migrations to and from the Gulf of Maine do not follow a defined route 
(NOAA Fisheries 2016c).
    Harbor porpoise occur seasonally in the winter and spring in small 
numbers in mid-Atlantic waters. Strandings occur primarily on ocean 
facing beaches, but they occasionally travel into the Chesapeake Bay to 
forage and could occur in the project area (Barco and Swingle 2014). 
Since 1999, stranding incidents have ranged widely from a high of 40 in 
1999 to 2 in 2011, 2012, and 2016 (Barco et al., 2017.

Harbor Seal

    Harbor seals occur in arctic and temperate coastal waters 
throughout the northern hemisphere, including on both the east and west 
coasts of the United States. On the east coast, harbor seals can be 
found from the Canadian Arctic down to Georgia (Blaylock 1985). Harbor 
seals occur year-round in Canada and Maine and seasonally (September-
May) from southern New England to New Jersey (NOAA Fisheries 2016d). 
The range of harbor seals appears to be shifting as they are regularly 
reported further south than they were historically. In recent years, 
they have established haul out sites in the Chesapeake Bay including on 
the portal islands of the CBBT (NOAA Fisheries 2016d, Rees et al., 
2016).
    Harbor seals are the most common seal in Virginia (Barco and 
Swingle 2014). They can be seen resting on the rocks around the portal 
islands of the CBBT from December through April. Seal observation 
surveys conducted at the CBBT recorded 112 harbor seals in the 2014/
2015 season and 184 harbor seals during the 2015/2016 season (Rees et 
al., 2016).
    The harbor seal is a medium-sized seal, reaching about 2 meters in 
length. They spend a fair amount of time hauled out on land, often in 
large groups (Rees et al., 2016). Haul out sites--which may be rocks, 
beaches, or ice--provide the opportunity for rest, thermal regulation, 
social interaction, parturition, and predator avoidance (NOAA Fisheries 
2017e).

Gray Seal

    Gray seals occur on both coasts of the Northern Atlantic Ocean and 
are divided into three major populations (NOAA Fisheries 2016b). The 
western north Atlantic stock occurs in eastern Canada and the 
northeastern United States, occasionally as far south as North 
Carolina. Gray seals inhabit rocky coasts and islands, sandbars, ice 
shelves and icebergs (NOAA Fisheries 2016b). In the United States, gray 
seals congregate in the summer to give birth at four established 
colonies in Massachusetts and Maine (NOAA Fisheries 2016b). From 
September through May, they disperse and can be abundant as far south 
as New Jersey. The range of gray seals appears to be shifting as they 
are regularly being reported further south than they were historically 
(Rees et al., 2016).
    Gray seals are uncommon in Virginia and the Chesapeake Bay. Only 15 
gray seal strandings were documented in Virginia from 1988 through 2013 
(Barco and Swingle 2014). They are rarely found resting on the rocks 
around the portal islands of the CBBT from December through April 
alongside harbor seals. Seal observation surveys conducted at the CBBT 
recorded one gray seal in each of the 2014/2015 and 2015/2016 seasons 
(Rees et al., 2016).
    Gray seals are a large seal at around 2-3 meters in length, and can 
dive to depths of 475 meters to capture prey. Like harbor seals, gray 
seals spend a fair amount of time hauled out on land to rest, 
thermoregulate, give birth or avoid predators (Rees et al., 2016).

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson, 1995; 
Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect this, 
Southall et al. (2007) recommended that marine mammals be divided into 
functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2016) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibels (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. The functional groups and 
the associated frequencies are indicated below (note that these 
frequency ranges correspond to the range for the composite group, with 
the entire range not necessarily reflecting the capabilities of every 
species within that group):
     Low-frequency cetaceans (mysticetes): generalized hearing 
is estimated to occur between approximately 7 hertz (Hz) and 35 
kilohertz (kHz), with best hearing estimated to be from 100 Hz to 8 
kHz;
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): generalized hearing is estimated to occur 
between approximately 150 Hz and 160 kHz;
     High-frequency cetaceans (porpoises, river dolphins, and 
members of the genera Kogia and Cephalorhynchus; including two members 
of the genus Lagenorhynchus, on the basis of recent echolocation data 
and genetic data): generalized hearing is estimated to occur between 
approximately 275 Hz and 160 kHz.
     Pinnipeds in water; Phocidae (true seals): generalized 
hearing is estimated to occur between approximately 50 Hz to 86 kHz;
     Pinnipeds in water; Otariidae (eared seals): generalized 
hearing is estimated to occur between 60 Hz and 39 kHz.
    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2016) for a review of available information. 
Four marine mammal species (two cetacean and two pinniped (two phocid) 
species) have the reasonable potential to co-occur with the proposed 
survey activities. Please refer to Table 2. Of the cetacean species 
that may be present, one is classified as a low-frequency cetacean 
(i.e., all mysticete species), one is classified as a

[[Page 18783]]

mid-frequency cetacean (i.e., all delphinid and ziphiid species) and 
one is classified as a high-frequency cetacean.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The ``Estimated Take by Incidental Harassment'' section 
later in this document includes a quantitative analysis of the number 
of individuals that are expected to be taken by this activity. The 
``Negligible Impact Analysis and Determination'' section considers the 
content of this section, the ``Estimated Take by Incidental 
Harassment'' section, and the ``Proposed Mitigation'' section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species or 
stocks.

Description of Sound

    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in Hz or cycles per second. Wavelength is the distance 
between two peaks of a sound wave; lower frequency sounds have longer 
wavelengths than higher frequency sounds and attenuate (decrease) more 
rapidly in shallower water. Amplitude is the height of the sound 
pressure wave or the `loudness' of a sound and is typically measured 
using the dB scale. A dB is the ratio between a measured pressure (with 
sound) and a reference pressure (sound at a constant pressure, 
established by scientific standards). It is a logarithmic unit that 
accounts for large variations in amplitude; therefore, relatively small 
changes in dB ratings correspond to large changes in sound pressure. 
When referring to sound pressure levels (SPLs; the sound force per unit 
area), sound is referenced in the context of underwater sound pressure 
to 1 micro pascal ([mu]Pa). One pascal is the pressure resulting from a 
force of one newton exerted over an area of one square meter. The 
source level (SL) represents the sound level at a distance of 1 m from 
the source (referenced to 1 [mu]Pa). The received level is the sound 
level at the listener's position. Note that all underwater sound levels 
in this document are referenced to a pressure of 1 [micro]Pa and all 
airborne sound levels in this document are referenced to a pressure of 
20 [micro]Pa.
    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, 1983). 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 
(Hastings and Popper 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. The 
compressions and decompressions associated with sound waves are 
detected as changes in pressure by aquatic life and man-made sound 
receptors such as hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound. Ambient 
sound is defined as environmental background sound levels lacking a 
single source or point (Richardson et al., 1995), and the sound level 
of a region is defined by the total acoustical energy being generated 
by known and unknown sources. These sources may include physical (e.g., 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
sound (e.g., vessels, dredging, aircraft, construction). A number of 
sources contribute to ambient sound, including the following 
(Richardson et al., 1995):
     Wind and waves: The complex interactions between wind and 
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of 
naturally occurring ambient noise for frequencies between 200 Hz and 50 
kHz (Mitson, 1995). In general, ambient sound levels tend to increase 
with increasing wind speed and wave height. Surf noise becomes 
important near shore, with measurements collected at a distance of 8.5 
km from shore showing an increase of 10 dB in the 100 to 700 Hz band 
during heavy surf conditions;
     Precipitation: Sound from rain and hail impacting the 
water surface can become an important component of total noise at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times;
     Biological: Marine mammals can contribute significantly to 
ambient noise levels, as can some fish and shrimp. The frequency band 
for biological contributions is from approximately 12 Hz to over 100 
kHz; and
     Anthropogenic: Sources of ambient noise related to human 
activity include transportation (surface vessels and aircraft), 
dredging and construction, oil and gas drilling and production, seismic 
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise 
typically dominates the total ambient noise for frequencies between 20 
and 300 Hz. In general, the frequencies of anthropogenic sounds are 
below 1 kHz and, if higher frequency sound levels are created, they 
attenuate rapidly (Richardson et al., 1995). Sound from identifiable 
anthropogenic sources other than the activity of interest (e.g., a 
passing vessel) is sometimes termed background sound, as opposed to 
ambient sound.
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving and vibratory pile 
extraction. The sounds produced by these activities fall into one of 
two general sound types: Pulsed and non-pulsed (defined in the 
following paragraphs). The distinction between these two sound types is 
important

[[Page 18784]]

because they have differing potential to cause physical effects, 
particularly with regard to hearing (e.g., Ward, 1997 in Southall et 
al., 2007). Please see Southall et al., (2007) for an in-depth 
discussion of these concepts.
    Pulsed sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986; Harris, 1998; ISO, 2003) and occur either as isolated 
events or repeated in some succession. Pulsed sounds are all 
characterized by a relatively rapid rise from ambient pressure to a 
maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or non-continuous (ANSI, 1995; 
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling, vibratory 
pile driving, and active sonar systems (such as those used by the 
United States Navy). The duration of such sounds, as received at a 
distance, can be greatly extended in a highly reverberant environment.
    Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper 2005). Vibratory 
hammers install piles by vibrating them and allowing the weight of the 
hammer to push them into the sediment. Vibratory hammers produce 
significantly less sound than impact hammers. Peak SPLs may be 180 dB 
or greater, but are generally 10 to 20 dB lower than SPLs generated 
during impact pile driving of the same-sized pile (Oestman et al., 
2009). Rise time is slower, reducing the probability and severity of 
injury, and sound energy is distributed over a greater amount of time 
(Nedwell and Edwards 2002).

Acoustic Impacts

    Please refer to the information given previously (Description of 
Sound) regarding sound, characteristics of sound types, and metrics 
used in this document. Anthropogenic sounds cover a broad range of 
frequencies and sound levels and can have a range of highly variable 
impacts on marine life, from none or minor to potentially severe 
responses, depending on received levels, duration of exposure, 
behavioral context, and various other factors. The potential effects of 
underwater sound from active acoustic sources can potentially result in 
one or more of the following: temporary or permanent hearing 
impairment, non-auditory physical or physiological effects, behavioral 
disturbance, stress, and masking (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007). The degree of 
effect is intrinsically related to the signal characteristics, received 
level, distance from the source, and duration of the sound exposure. In 
general, sudden, high level sounds can cause hearing loss, as can 
longer exposures to lower level sounds. Temporary or permanent loss of 
hearing will occur almost exclusively for noise within an animal's 
hearing range. In this section, we first describe specific 
manifestations of acoustic effects before providing discussion specific 
to the proposed construction activities in the next section.
    Permanent Threshold Shift--Marine mammals exposed to high-intensity 
sound, or to lower-intensity sound for prolonged periods, can 
experience hearing threshold shift (TS), which is the loss of hearing 
sensitivity at certain frequency ranges (Kastak et al., 1999; Schlundt 
et al., 2000; Finneran et al., 2002, 2005). TS can be permanent (PTS), 
in which case the loss of hearing sensitivity is not fully recoverable, 
or temporary (TTS), in which case the animal's hearing threshold would 
recover over time (Southall et al., 2007). Repeated sound exposure that 
leads to TTS could cause PTS. In severe cases of PTS, there can be 
total or partial deafness, while in most cases the animal has an 
impaired ability to hear sounds in specific frequency ranges (Kryter 
1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several dB above (a 40-dB threshold shift approximates PTS 
onset; e.g., Kryter et al., 1966; Miller 1974) that inducing mild TTS 
(a 6-dB threshold shift approximates TTS onset; e.g., Southall et al., 
2007). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulse sounds (such as 
impact pile driving pulses as received close to the source) are at 
least six dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level thresholds (Southall et al., 
2007).
    Temporary threshold shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to sound (Kryter 1985). While 
experiencing TTS, the hearing threshold rises, and a sound must be at a 
higher level in order to be heard. In terrestrial and marine mammals, 
TTS can last from minutes or hours to days (in cases of strong TTS). In 
many cases, hearing sensitivity recovers rapidly after exposure to the 
sound ends.
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS, and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to 
serious. For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that occurs during a time where ambient noise is lower and there 
are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)); and three species of pinnipeds (northern elephant 
seal (Mirounga angustirostris), 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; 
Nachtigall et al., 2004; Kastak et al., 2005; Lucke et al.,

[[Page 18785]]

2009; Popov et al., 2011). 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. 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).
    Auditory masking--Sound can disrupt behavior through masking, or 
interfering with, an animal's ability to detect, recognize, or 
discriminate between acoustic signals of interest (e.g., those used for 
intraspecific communication and social interactions, prey detection, 
predator avoidance, navigation) (Richardson et al., 1995). Masking 
occurs when the receipt of a sound is interfered with by another 
coincident sound at similar frequencies and at similar or higher 
intensity, and may occur whether the sound is natural (e.g., snapping 
shrimp, wind, waves, precipitation) or anthropogenic (e.g., shipping, 
sonar, seismic exploration) in origin. The ability of a noise source to 
mask biologically important sounds depends on the characteristics of 
both the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
when disrupting or altering critical behaviors. It is important to 
distinguish TTS and PTS, which persist after the sound exposure, from 
masking, which occurs during the sound exposure. Because masking 
(without resulting in TS) is not associated with abnormal physiological 
function, it is not considered a physiological effect, but rather a 
potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007b; Di Iorio and Clark 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore 2014). Masking can be tested 
directly in captive species (e.g., Erbe, 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand, 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking. 
Note that any masking event that could possibly rise to Level B 
harassment under the MMPA would occur concurrently within the zones of 
behavioral harassment already estimated for vibratory and impact pile 
driving, and which have already been taken into account in the exposure 
analysis.
    Behavioral effects--Behavioral disturbance may include a variety of 
effects, including subtle changes in behavior (e.g., minor or brief 
avoidance of an area or changes in vocalizations), more conspicuous 
changes in similar behavioral activities, and more sustained and/or 
potentially severe reactions, such as displacement from or abandonment 
of high-quality habitat. Behavioral responses to sound are highly 
variable and context-specific and any reactions depend on numerous 
intrinsic and extrinsic factors (e.g., species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day), as well as the interplay between factors (e.g., 
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007; 
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not 
only among individuals but also within an individual, depending on 
previous experience with a sound source, context, and numerous other 
factors (Ellison et al., 2012), and can vary depending on 
characteristics associated with the sound source (e.g., whether it is 
moving or stationary, number of sources, distance from the source). 
Please see Appendices B-C of Southall et al. (2007) for a review of 
studies involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure. As noted, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a

[[Page 18786]]

particular instance might affect marine mammals perceiving the signal. 
If a marine mammal does react briefly to an underwater sound by 
changing its behavior or moving a small distance, the impacts of the 
change are unlikely to be significant to the individual, let alone the 
stock or population. However, if a sound source displaces marine 
mammals from an important feeding or breeding area for a prolonged 
period, impacts on individuals and populations could be significant 
(e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 2003). However, 
there are broad categories of potential response, which we describe in 
greater detail here, that include alteration of dive behavior, 
alteration of foraging behavior, effects to breathing, interference 
with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely, and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al.; 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.,; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007b). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus 1996). The result of a flight response could range from brief, 
temporary exertion and displacement from the area where the signal 
provokes flight to, in extreme cases, marine mammal strandings (Evans 
and England 2001). However, it should be noted that response to a 
perceived predator does not necessarily invoke flight (Ford and Reeves 
2008), and whether individuals are solitary or in groups may influence 
the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either

[[Page 18787]]

exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC 2003).
    Non-auditory physiological effects--Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, resonance effects, and other types of organ 
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies 
examining such effects are limited. In general, little is known about 
the potential for pile driving to cause auditory impairment or other 
physical effects in marine mammals. Available data suggest that such 
effects, if they occur at all, would presumably be limited to short 
distances from the sound source, where SLs are much higher, 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) or any 
meaningful quantitative predictions of the numbers (if any) of marine 
mammals that might be affected in those ways. However, the proposed 
activities do not involve the use of devices such as explosives or mid-
frequency active sonar that are associated with these types of effects. 
Therefore, non-auditory physiological impacts to marine mammals are 
considered unlikely.
    Airborne Acoustic Effects from the Proposed Activities--Pinnipeds 
that occur near the project site could be exposed to airborne sounds 
associated with pile driving that have the potential to cause 
behavioral harassment, depending on their distance from pile driving 
activities. Cetaceans are not expected to be exposed to airborne sounds 
that would result in harassment as defined under the MMPA.
    Airborne noise will primarily be an issue for pinnipeds that are 
swimming or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. We recognize that 
pinnipeds in the water could be exposed to airborne sound that may 
result in behavioral harassment when looking with heads above water. 
Most likely, airborne sound would cause behavioral responses similar to 
those discussed above in relation to underwater sound. However, these 
animals would previously have been ``taken'' as a result of exposure to 
underwater sound above the behavioral harassment thresholds, which are 
in all cases larger than those associated with airborne sound. Thus, 
the behavioral harassment of these animals is already accounted for in 
these estimates of potential take. Multiple instances of exposure to 
sound above NMFS' thresholds for behavioral harassment are not believed 
to result in increased behavioral disturbance, in either nature or 
intensity of disturbance reaction.
    Potential Pile Driving Effects on Prey--Construction activities 
would produce continuous (i.e., vibratory pile driving) sounds and 
pulsed (i.e., impact driving) sounds. Fish react to sounds that are 
especially strong and/or intermittent low-frequency sounds. Short 
duration, sharp sounds can cause overt or subtle changes in fish 
behavior and local distribution. Hastings and Popper (2005) identified 
several studies that suggest fish may relocate to avoid certain areas 
of sound energy. Additional studies have documented effects of pile 
driving on fish, although several are based on studies in support of 
large, multiyear bridge construction projects (e.g., Scholik and Yan, 
2001, 2002; Popper and Hastings, 2009). Sound pulses at received levels 
of 160 dB may cause subtle changes in fish behavior. SPLs of 180 dB may 
cause noticeable changes in behavior (Pearson et al., 1992; Skalski et 
al., 1992). SPLs of sufficient strength have been known to cause injury 
to fish and fish mortality.
    The most likely impact to fish from pile driving activities at the 
project area would be temporary behavioral avoidance within an 
undetermined portion of the affected area. The duration of fish 
avoidance of this area after pile driving stops is unknown, but a rapid 
return to normal recruitment, distribution and behavior is anticipated. 
In general, impacts to marine mammal prey species from the proposed 
project are expected to be minor and temporary due to the relatively 
short timeframe of pile driving and extraction.
    Effects to Foraging Habitat--Pile installation may temporarily 
impact foraging habitat by increasing turbidity resulting from 
suspended sediments. Any increases would be temporary, localized, and 
minimal. The contractor must comply with state water quality

[[Page 18788]]

standards during these operations by limiting the extent of turbidity 
to the immediate project area. In general, turbidity associated with 
pile installation is localized to about a 25-foot radius around the 
pile (Everitt et al., 1980). Furthermore, water quality impacts are 
expected to be negligible because the project area occurs in a high 
energy, dynamic area with strong tidal currents. Cetaceans are not 
expected to be close enough to the project pile driving areas to 
experience effects of turbidity, and any pinnipeds will be transiting 
the area and could avoid localized areas of turbidity. Therefore, the 
impact from increased turbidity levels is expected to be discountable 
to marine mammals.
    It is important to note that pile driving and removal activities at 
the project site will not obstruct movements or migration of marine 
mammals.
    In summary, given the relatively short and intermittent nature of 
sound associated with individual pile driving and extraction events and 
the relatively small area that would be affected, pile driving 
activities associated with the proposed action are not likely to have a 
permanent, adverse effect on any fish habitat, or populations of fish 
species. Thus, any impacts to marine mammal habitat are not expected to 
cause significant or long-term consequences for individual marine 
mammals or their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would be by Level B harassment, in the form of 
disruption of behavioral patterns for individual marine mammals 
resulting from exposure to acoustic sources including impact and 
vibratory pile driving equipment. There is also some potential for 
auditory injury (Level A harassment) to result, due to larger predicted 
auditory injury zones. The proposed mitigation and monitoring measures 
are expected to minimize the severity of such taking to the extent 
practicable.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Described in the most basic way, we estimate take by considering: 
(1) Acoustic thresholds above which NMFS believes the best available 
science indicates marine mammals will be behaviorally harassed or incur 
some degree of permanent hearing impairment; (2) the area or volume of 
water that will be ensonified above these levels in a day; (3) the 
density or occurrence of marine mammals within these ensonified areas; 
and (4) and the number of days of activities. Below, we describe these 
components in more detail and present the proposed take estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B harassment) or to incur PTS 
of some degree (equated to Level A harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2011). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g. 
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms) 
for non-explosive impulsive (e.g., impact pile driving, seismic 
airguns) or intermittent (e.g., scientific sonar) sources.
    CTJV's proposed activity includes the use of continuous (vibratory 
pile driving) and impulsive (impact pile driving) sources, and 
therefore the 120 and 160 dB re 1 [mu]Pa (rms) are applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Technical Guidance, 2016) identifies dual criteria to 
assess auditory injury (Level A harassment) to five different marine 
mammal groups (based on hearing sensitivity) as a result of exposure to 
noise from two different types of sources (impulsive or non-impulsive). 
CTJV's tunnel project includes the use of impulsive (impact hammer) and 
non-impulsive (vibratory hammer) sources.
    These thresholds are provided in Table 3 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2016 Technical Guidance, which may be accessed at: 
https://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS Onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199dB.
                                          LE,LF,24h: 183dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185dB.

[[Page 18789]]

 
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
  has a reference value of 1 [micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
  NAtional Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
  incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
  ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
  generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
  the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
  be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
  it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

    Although CTJV's construction activity includes the use of impulsive 
(impact pile driving) and non-impulsive (vibratory pile driving and 
drilling) sources, the shutdown zones set by the applicant are large 
enough to ensure Level A harassment will be prevented. To assure the 
largest shutdown zone can be fully monitored, protected species 
observers (PSOs) will be positioned in the possible best vantage points 
during all piling/drilling activities to guarantee a shutdown if marine 
mammals approach or enter the designated shutdown zone. These measures 
are described in full detail below in the Proposed Mitigation and 
Proposed Monitoring and Reporting Sections.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds.
    Pile driving will generate underwater noise that potentially could 
result in disturbance to marine mammals swimming by the project area. 
Transmission loss (TL) underwater is the decrease in acoustic intensity 
as an acoustic pressure wave propagates out from a source until the 
source becomes indistinguishable from ambient sound. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. A standard sound propagation model, the Practical 
Spreading Loss model, was used to estimate the range from pile driving 
activity to various expected SPLs at potential project structures. This 
model follows a geometric propagation loss based on the distance from 
the driven pile, resulting in a 4.5 dB reduction in level for each 
doubling of distance from the source. In this model, the SPL at some 
distance away from the source (e.g., driven pile) is governed by a 
measured source level, minus the TL of the energy as it dissipates with 
distance. The TL equation is:

TL = 15log10(R1/R2)

Where:

TL is the transmission loss in dB,
R1 is the distance of the modeled SPL from the driven 
pile, and
R2 is the distance from the driven pile of the initial 
measurement.

    The degree to which underwater noise propagates away from a noise 
source is dependent on a variety of factors, most notably by the water 
bathymetry and presence or absence of reflective or absorptive 
conditions including the sea surface and sediment type. The TL model 
described above was used to calculate the expected noise propagation 
from both impact and vibratory pile driving, using representative 
source levels to estimate the harassment zone or area exceeding 
specified noise criteria.

Source Levels

    Sound source levels from the PTST project site were not available. 
Therefore, literature values published for projects similar to the PTST 
project were used to estimate the amount of sound (RMS SPL) that could 
potentially be produced. The PTST Project will use round, 36-inch-
diameter, hollow steel piles and 28-inch wide sheet piles. Data 
reported in the Compendium of Pile Driving Sound Data (Caltrans 2015) 
for similar piles size and types are shown in Table 4. The use of an 
encased bubble curtain is expected to reduce sound levels by 10 dB 
(NAVFAC 2014, ICF Jones and Stokes 2009). Using data from previous 
projects (Caltrans 2015) and the amount of sound reduction expected 
from each of the sound mitigation methods, we estimated the peak noise 
level (SPLpeak), the root mean squared sound pressure level (RMS SPL), 
and the single strike sound exposure level (sSEL) for each pile driving 
scenario of the PTST project (Table 4).

                                  Table 4--The Sound Levels (dB Peak, dB RMS, and dB Ssel) Expected To Be Generated by
                                                               Each Hammer Type/Mitigation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Estimated                       Estimated
                                                 Estimated peak    cumulative       Estimated     single strike
         Type of pile             Hammer type      noise level   sound exposure  pressure level  sound exposure  Relevant piles at the    Pile function
                                                    (dB peak)       level (dB       (dB RMS)        level (dB         PTST project
                                                                      cSEL)                           sSEL)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch Steel Pipe...........  Impact \a\......             210              NA             193             183  Battered.............  Mooring
                                                                                                                                         dolphins.
36-inch Steel Pipe...........  Impact with                  200              NA             183             173  Plumb................  Mooring dolphins
                                Bubble Curtain                                                                                           and Temporary
                                \b\.                                                                                                     Pier.
24-inch AZ Sheet.............  Vibratory \c\...             182              NA             154             165  Sheet................  Containment
                                                                                                                                         Structure.
36-inch Steel Pipe and 24-     Impact w/Bubble              200              NA             186             183  Plumb................  Mooring
 inch AZ Sheet Pile.            Curtain at PI 1                                                                                          Dolphins,
                                and PI 2 \d\.                                                                                           Temporary Pier.

[[Page 18790]]

 
36-inch Steel Pipe and 24-     Impact w/Bubble              200              NA             183             183  Plumb and Sheet......  Mooring
 inch AZ Sheet Pile.            Curtain at PI 1                                                                                          Dolphins,
                                and Vibratory                                                                                            Containment
                                at PI 2.                                                                                                 Structure.
36-inch Steel Pipe and 24-     Vibratory at PI              200              NA             183             183  Plumb and Sheet......  Mooring Dolphins
 inch AZ Sheet Pile.            1 and Impact w/                                                                                          and Containment
                                Bubble Curtain                                                                                           Structure.
                                at PI 2.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Examples from Caltrans 2015. These examples were the loudest provided in the Caltrans 2015 compendium for 36-inch-diameter hollow steel piles and in
  the Proxy Source Sound Levels and Potential Bubble Curtain Attenuation for Acoustic Modeling of nearshore marine Pile Driving at Navy Installations in
  Puget Sound (NAVFAC 2014).
\b\ Estimates of sound produced from impact that use sound mitigation measures were developed by subtracting 10 dB for an encased bubble curtain (ICF
  Jones and Stokes 2009, NAVFAC 2014). A 10-dB reduction in sound for this sound mitigation method is the minimum that may be expected and, therefore,
  represents a conservative estimate in sound reduction.
\c\ Example from NAVFAC 2017. Average 1-second and 10-second Broadband RMS SPL (dB re 1 [micro]Pa) for Vibratory Pile-Driving normalized to 10 meters at
  JEB Little Creek.
\d\ Simultaneous pile driving were determined by applying the rules of dB addition outlined in the Biological Assessment Advanced Training Manual
  Version 4-2017 (WSDOT 2017).

    When NMFS's Technical Guidance (2016) was published, in recognition 
of the fact that ensonified area/volume could be more technically 
challenging to predict because of the duration component in the new 
thresholds, we developed a User Spreadsheet that includes tools to help 
predict a simple isopleth that can be used in conjunction with marine 
mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which will result in some degree of 
overestimate of Level A take. However, these tools offer the best way 
to predict appropriate isopleths when more sophisticated 3D modeling 
methods are not available, and NMFS continues to develop ways to 
quantitatively refine these tools, and will qualitatively address the 
output where appropriate. For stationary sources, NMFS's User 
Spreadsheet predicts the closest distance at which, if a marine mammal 
remained at that distance the whole duration of the activity, it would 
not incur PTS. Inputs used in the User Spreadsheet, and the resulting 
isopleths are reported below.
    The Impact Pile Driving (Stationary Source: Impulsive, 
Intermittent) (Sheet E.1) spreadsheet provided by NOAA Fisheries 
requires inputs for assorted variables which are shown in Table 4. RMS 
SPL's for simultaneous pile driving were determined using the rules for 
dB addition (WSDOT 2017). The expected number of steel piles driven 
during a 24-hour period would be a maximum of eight for plumb piles and 
three for battered piles for each portal island. Practical spreading 
was assumed (15logR) and a pulse duration of 0.1 seconds utilized. The 
distance from the source where the literature based RMS SPL was 10 
meters while the number of strikes per pile was 1,000. Model outputs 
delineating PTS isopleths are provided in Table 6 assuming impact 
installation of three battered round steel piles per day and eight 
plumb round steel piles per day as well as vibratory installation of up 
to eight sheets per day over eight hours.
    The Optional User Spreadsheet for vibratory pile driving (non-
impulsive, stationary, continuous) (Sheet A) requires inputs for the 
sound pressure level of the source (dB RMS SPL), the expected activity 
duration in hours during per 24-hour period, the propagation of the 
sound and the distance from the source at which the sound pressure 
level was measured. Calculations also assumed that the expected 
activity level duration would be eight hours per Portal Island per 24-
hour period. Practical spreading was assumed and the measured distance 
from the sound source was 10 meters.
    The inputs from Table 5 determined isopleths where PTS from 
underwater sound during impact and vibratory driving as shown in Table 
6.

                     Table 5--Inputs for Determining Distances to Cumulative PTS Thresholds
----------------------------------------------------------------------------------------------------------------
                               E.1: Impact pile    E.1: Impact                       E.1: Impact     E.1: Impact
                                    driving        pile driving    A: Stationary     pile driving   pile driving
                                  (stationary      (stationary      source: non-     (stationary     (stationary
     Spreadsheet tab used           source:          source:         impulsive,        source:         source:
                                  impulsive,        impulsive,       continuous       impulsive,     impulsive,
                                 intermittent)    intermittent)                     intermittent)   intermittent
----------------------------------------------------------------------------------------------------------------
Pile Type and Hammer Type....  36-in steel       36-in steel      28-in sheet      36-in steel      36-in steel
                                impact            impact w/        vibratory.       impact w/       impact w/
                                (battered pile).  bubble curtain                    bubble curtain  bubble
                                                  (plumb pile).                     at P1 and P2    curtain at
                                                                                    (plumb piles).  P1 (plumb
                                                                                                    pile) and
                                                                                                    sheet pile
                                                                                                    vibratory at
                                                                                                       P2.
Source Level (RMS SPL).......  193.............  183............  154............  186............    183.
Weighting Factor Adjustment    2...............  2..............  2.5............  2..............      2.
 (kHz).
Number of strikes in 1 h OR    1,000...........  1,000..........  NA.............  1,000..........  1,000.
 number of strikes per pile.
Activity Duration (h) within   3 steel piles...  8 steel piles..  8 hours/8        8 steel piles    8 steel
 24-h period OR number of                                          sheets.          per portal      piles.
 piles per day.                                                                     island.
Propagation (xLogR)..........  15..............  15.............  15.............  15.............     15.
Distance of source level       10..............  10.............  10.............  10.............     10.
 measurement (meters).
Pulse Duration (seconds).....  0.1.............  0.1............  NA.............  0.1............    0.1.
----------------------------------------------------------------------------------------------------------------


[[Page 18791]]


              Table 6--Radial Distance (Meters) From Pile Driven From Portal Island 1 (PI 1) and Portal Island 2 (PI 2) to PTS Isopleths *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Low-frequency       Mid-frequency      High-frequency     Phocid  pinnipeds
                                                 cetaceans           cetaceans           cetaceans     --------------------    Applicable piles in the
                Hammer type                ------------------------------------------------------------                             PTST project
                                            Island 1  Island 2  Island 1  Island 2  Island 1  Island 2  Island 1  Island 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact (battered) at PI 1 OR PI 2.........   2,077.2   2,077.2      73.9      73.9   2,474.3   2,474.3   1,111.6   1,111.6  Battered Piles for Mooring
                                                                                                                             Dolphins.
Impact with Bubble Curtain (plumb) at PI 1     860.6     860.6      30.6      30.6   1,025.1   1,025.1     460.5     460.5  Plumb Piles for Temporary
 OR PI 2.                                                                                                                    Pier and Mooring Dolphins.
Vibratory.................................       9.3       9.3       0.8       0.8      13.8      13.8       5.7       5.7  Sheet Piles for Containment.
Impact w/Bubble Curtain (plumb)              1,363.9   1,363.9      48.5      48.5   1,624.7   1,624.7     729.9     729.9  Plumb Piles for temporary
 simultaneous at PI 1 and PI 2.                                                                                              pier.
Impact w/Bubble Curtain (plumb)                860.6       9.3      30.6       0.8   1,025.1      13.8     460.5       5.7  Plumb Piles for Temporary
 simultaneous at PI 1 and Vibratory at PI                                                                                    Pier and Mooring Dolphins;
 2.                                                                                                                          Sheet Pile for Containment.
Vibratory at PI 1 and Impact w/Bubble            9.3     860.6       0.8      30.6      13.8   1,025.1       5.7     460.5  Plumb Piles for temporary
 Curtain (plumb) at PI 2 Simultaneous.                                                                                       pier and Mooring Dolphins;
                                                                                                                             Sheet Pile for Containment.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Distances based on up to 3 battered round steel piles per day, 8 plumb round steel piles per day, and up to 8 sheets per day over 8 hours.

    Table 7 shows the radial distance to Level B isopleths and Table 8 
shows the areas of ensonified Level B zones associated with each of the 
planned driving scenarios.

       Table 7--Radial Distance (Meters) From Pile Driven to Level B Isopleths for Cetaceans and Pinnipeds
----------------------------------------------------------------------------------------------------------------
                                                               Radial distance (m)  160
                                                                     (impact)/ 120
 Hearing group sound threshold  (dB)    Hammer type driving           (vibratory)        Applicable piles in the
                                              scenario        --------------------------       PTST project
                                                                 Island 1     Island 2
----------------------------------------------------------------------------------------------------------------
PTS Isopleth to threshold (meters)..  Impact (battered)......      1,584.9      1,584.9  Battered Piles for
                                                                                          Mooring Dolphins.
PTS Isopleth to threshold (meters)..  Impact with Bubble             341.5        341.5  Plumb Piles for
                                       Curtain.                                           Temporary Pier and
                                                                                          Mooring Dolphins.
PTS Isopleth to threshold (meters)..  Vibratory..............      1,847.8      1,847.8  Sheet Piles for
                                                                                          Containment.
PTS Isopleth to threshold (meters)..  Impact w/Bubble Curtain        541.2        541.2  Plumb Piles for
                                       (plumb) at PI 1 and PI                             temporary pier.
                                       2 simultaneous.
PTS Isopleth to threshold (meters)..  Impact w/Bubble Curtain        341.5      1,847.8  Plumb Piles for
                                       (plumb) at PI 1 and                                Temporary Pier and
                                       Vibratory at PI 2                                  Mooring Dolphins;
                                       simultaneous.                                      Sheet Pile for
                                                                                          Containment.
PTS Isopleth to threshold (meters)..  Vibratory at PI 1 and        1,847.8        341.5  Plumb Piles for
                                       Impact w/Bubble                                    temporary pier and
                                       Curtain (plumb) at PI                              Mooring Dolphins;
                                       2 simultaneous.                                    Sheet Pile for
                                                                                          Containment.
----------------------------------------------------------------------------------------------------------------


  Table 8--Level B Areas (km\2\) for All Pile Driving Scenarios Planned
                       for Use During PTST Project
------------------------------------------------------------------------
                                                                   Zone
                            Scenario                               size
                                                                 (km\2\)
------------------------------------------------------------------------
Impact Plumb...................................................     0.45
Impact Simultaneous Plumb......................................     2.08
Impact Battered................................................     8.27
Vibratory Sheet................................................    12.27
Simultaneous Vibratory Sheet and Impact Plumb..................    12.27
------------------------------------------------------------------------

    To calculate level B disturbance zones for airborne noise from pile 
driving, the spherical spreading loss equation (20LogR) was used to 
determine the Level B zones. The airborne noise threshold for 
behavioral harassment for all pinnipeds, except harbor seals, is 100 dB 
RMS re 20 [micro]Pa (unweighted) and for harbor seals is 90 dB RMS re 
20 [micro]Pa (unweighted).
    Literature estimates were used to estimate the amount of in-air 
sound produced from driving a pile above the MHW line (Laughlin 
2010a,b). Hollow steel piles that were 30 inches in diameter were used 
as a close proxy to the 36-inch-diameter hollow steel piles that will 
be driven at the PTST project. AZ 24-inch sheet pile was used as a 
proxy for the sheet pile to be driven during the PTST Project (Table 
9). Using the spherical spreading loss model with these estimates, 
Level B isopleths were estimated as shown below in Table 9. Note that 
the take estimates for pinnipeds were based on surveys which included 
counts of hauled out animals. Therefore, to avoid double counting, 
airborne exposures are not evaluated further for purposes of estimating 
take under the proposed IHA. During any upland pile driving before 
issuance of the IHA, however, shutdown will occur whenever pinnipeds 
enter into the Level B zones as depicted below to avoid unauthorized 
take.

  Table 9--Radial Distance (Meters) From Pile Driven Above MHW to Level B Sound Thresholds for Harbor Seals and
                                                   Gray Seals
----------------------------------------------------------------------------------------------------------------
                                                                      Level A      Level B harassment zone  (m)
                Source                         Sound level          harassment   -------------------------------
                                                                     zone  (m)     Harbor Seals     Gray Seals
----------------------------------------------------------------------------------------------------------------
Impact Hammer 36-inch Pile............  110 dBL5SEQ at 15m \a\..             N/A             150              47

[[Page 18792]]

 
Vibratory Hammer Assumed equivalent to  92 dBL5SEQ at 15m.......             N/A              19               6
 24-in sheet.
----------------------------------------------------------------------------------------------------------------
\a\ Laughlin 2010a,b as cited in City of Unalaska 2016 IHA for Unalaska Marine Center.

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    Humpback whales are relatively rare in the Chesapeake Bay but may 
be found within or near the Chesapeake Bay at any time of the year. 
Between 1998 and 2014, 11 humpback whale stranding were reported within 
the Chesapeake Bay (Barco and Swingle 2014). Strandings occurred in all 
seasons, but were most common in the spring. There is no existing 
density data for this species within or near the Chesapeake Bay. 
Populations in the mid-Atlantic have been estimated for humpback whales 
off the coast of New Jersey with a density of 0.000130 per square 
kilometer (Whitt et al., 2015). A similar density may be expected off 
the coast of Virginia.
    Bottlenose dolphins are abundant along the Virginia coast and 
within the Chesapeake Bay and can be seen seen annually in Virginia 
from May through October. Approximately 65 strandings are reported each 
year (Barco and Swingle 2014). Stranded bottlenose dolphins have been 
recorded as far north as the Potomac River in the Chesapeake Bay 
(Blaylock 1985). A 2016 Navy report on the occurrence, distribution, 
and density of marine mammals near Naval Station Norfolk and Virginia 
Beach, Virginia provides seasonal densities of bottlenose dolphins for 
inshore areas in the vicinity of the project area (Engelhaupt et al., 
2016) (Table 10).
    There is little data on the occurrence of harbor porpoises in the 
Chesapeake Bay. Harbor porpoises are the second most common marine 
mammal to strand in Virginia waters with 58 reported strandings between 
2007 through 2016. Unlike bottlenose dolphins, harbor porpoises are 
found in Virginia in the cooler months, primarily late winter and early 
spring, and they strand primarily on ocean facing beaches (Barco et 
al., 2017).
    Harbor seals are the most common seal in Virginia (Barco and 
Swingle 2014). They can be seen resting on the rocks around the portal 
islands of the CBBT from December through April. They are unlikely to 
occur in the project area in the summer and early fall. Survey data for 
in-water and hauled out harbor seals was collected by the United States 
Navy at the CBBT portal islands from 2014 through 2016 (Rees et al., 
2016) (Table 12). Surveys reported 112 harbor seals in the 2014/2015 
season and 184 harbor seals during the 2015/2016 season. (Rees et al., 
2016).
    Gray seals are uncommon in Virginia and the Chesapeake Bay with 
only 15 gray seal strandings documented in Virginia from 1988-2013 
(Barco and Swingle 2014). They are rarely found resting on the rocks 
around the portal islands of the CBBT from December through April 
alongside harbor seals. Observation surveys conducted by the Navy at 
the CBBT portal islands recorded one gray seal in each of the 2014/2015 
and 2015/2016 seasons (Rees et al., 2016).

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate.
    The following assumptions are made when estimating potential 
incidences of take:
     All marine mammal individuals potentially available are 
assumed to be present within the relevant area, and thus incidentally 
taken;
     An individual can only be taken once during a 24-h period;
     Exposures to sound levels at or above the relevant 
thresholds equate to take, as defined by the MMPA.

Humpback Whale

    As noted previously, humpback whales are rare in the Chesapeake 
Bay, although they do occur. Density off of the coast of New Jersey, 
and presumably Virginia and Maryland, is extremely low (0.00013 
animals/km\2\). Because density is extremely low, the CTJV is 
requesting and NMFS is proposing one Level B take every two months for 
the duration of in-water pile driving activities. Pile driving 
activities are expected to occur over a 10-month period. Therefore, a 
total of 5 Level B takes of humpback whales is proposed by NMFS.

Bottlenose Dolphin

    Total number of takes for bottlenose dolphin were calculated using 
the seasonal density described above (individuals/km\2\/day) of animals 
within the inshore study area at the mouth of the Chesapeake Bay 
(Englehaupt et al., 2016). Project specific dolphin densities were 
calculated within the respective Level B harassment zone and season. 
Densities were then used to calculate the seasonal takes based on the 
number and type of pile driving days per season. For example, the 
density of dolphins in summer months is assumed to be 3.55 dolphins/
km\2\ * 2.08 km\2\ (harassment zone for Simultaneous Plumb Pile driving 
as shown in Table 8) = 7.38 dolphins/km\2\ per day in summer as shown 
in Table 11. This density was then multiplied by number of simultaneous 
plumb pile driving days to provide takes for that season (e.g. 7.38 
dolphins/km\2\ * 24 days = 177 estimated summer exposures from 
simultaneous plumb pile driving). The sum of the anticipated number of 
seasonal takes resulted in 3,708 estimated exposures as shown in Table 
10 split among three stocks. There is insufficient information to 
apportion the takes precisely to the three stocks present in the area. 
Given that members of the NNCES stock are thought to occur in or near 
the Bay in very small numbers, and only during July and August, we will 
conservatively assume that no more than 100 of the takes will be from 
this stock. Most animals from this stock spend the summer months in 
Pamlico Sound and the range of species extends as far south as 
Beaufort, NC. In colder months, animals are thought to go no farther 
north than Pamlico Sound. Since members of the southern migratory 
coastal and northern migratory coastal stocks are known to occur in or 
near the Bay in greater numbers, we will conservatively assuming that 
no more than half of the remaining animals (1,804) will accrue to 
either of these stocks.). The largest level B zone for mid-frequency 
cetaceans occurs during

[[Page 18793]]

vibratory driving and extends out 1,847.8 meters. The largest Level A 
isopleth is 73.9 meters and would occur during installation of three 
battered piles on a single day. NMFS proposes a shutdown zone that 
extends 200 m, so no Level A take is proposed.

                 Table 10--Summary of Information Used To Calculate Bottlenose Dolphin Exposures
----------------------------------------------------------------------------------------------------------------
                                                                      Density        Estimated     Total number
                             Season                                (individuals   number of pile   of requested
                                                                    per km\2\)     driving days        takes
----------------------------------------------------------------------------------------------------------------
Summer 2018.....................................................            3.55              45             879
Fall 2018.......................................................            3.88              77           2,242
Winter 2019.....................................................            0.63              70             464
Spring 2019.....................................................            1.00              10             123
                                                                 -----------------------------------------------
    Total.......................................................  ..............  ..............           3,708
----------------------------------------------------------------------------------------------------------------


        Table 11--Seasonal Daily Take by Driving Scenario (Seasonal Density * Scenario Zone Size) and Estimated Number of Driving Days per Season
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                        Simultaneous
                                                Impact plumb         Impact         Impact batter    Vibratory sheet   vibratory sheet
                   Season                        daily take       simultaneous    daily take (days/ daily take (days/ and impact plumb   Number of pile
                                                (days/season)   plumb daily take       season)           season)      daily take (days/   driving days
                                                                  (days/season)                                            season)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Summer......................................          1.61 (0)         7.38 (24)        29.37 (15)         43.55 (6)         43.55 (0)                45
Fall........................................          1.76 (0)         8.06 (36)         32.10 (0)        47.60 (41)         47.60 (0)                77
Winter......................................          0.28 (0)         1.31 (12)          5.21 (0)         7.73 (34)         7.73 (24)                70
Spring......................................          0.45 (0)          2.08 (0)          8.27 (0)         12.27 (9)         12.27 (1)                10
--------------------------------------------------------------------------------------------------------------------------------------------------------

Harbor Porpoise

    Little is known about the abundance of arbor porpoises in the 
Chesapeake Bay. A recent survey of the Maryland Wind Energy Area found 
that porpoises occur frequently offshore January to May (Wingfield et 
al., 2017). This finding reflects the pattern of winter and spring 
strandings in the mid-Atlantic. NMFS will assume that there is a 
porpoise sighting once during every two months of operations. That 
would equate to five sightings over ten months. Assuming an average 
group size of two results in a total estimated take of 10 porpoises. 
Harbor porpoises are members of the high-frequency hearing group which 
would have Level A isopleths as large of 2,474 meters during impact 
installation of three battered piles per day. Given the relatively 
large Level A zones during impact driving, NMFS proposes to authorize 
the take of 4 porpoises by Level A take and 6 by Level B take.

Harbor Seal

    The number of harbor seals expected to be present in the PTST 
project area was estimated using survey data for in-water and hauled 
out seals collected by the United States Navy at the portal islands 
from 2014 through 2016 (Rees et al., 2016). The survey data were used 
to estimate the number of seals observed per hour for the months of 
January-May and October-December between 2014 and 2016. Seal density 
data are in the format of seal per unit time. Therefore, potential seal 
exposures were calculated as total number of potential seals per pile 
driving day (8 hours) multiplied by the number of pile driving days per 
month. For example, in November seal density data are reported at 0.1 
seals per hour, within an 8-hour work day there may be 0.8 seals * 27 
work days in November, resulting in 22 seal takes. The anticipated 
numbers of monthly exposures were summed. NMFS proposes to authorize 
the take of 7,537 harbor seals (Table 12). The largest level B zone 
would occur during vibratory driving and extends out 1,847.8 meters 
from the sound source. The largest Level A isopleth is 1,111.6 meters 
which would occur during impact installation of three battered piles. 
The smallest Level A zone during impact driving is 115 meters which 
would occur when a single steel pile is impact driven at the same time 
that vibratory driving of sheet piles is occurring. NMFS proposes a 
shutdown zone for harbor seals of 50 meters since seals are common in 
the project area and are known to approach the shoreline. A larger 
shutdown zone would likely result in multiple shutdowns and impede the 
project schedule. NMFS will assume that 20 percent of the exposed seals 
will occur within the Level A zone specified for a given scenario. 
Therefore, NMFS proposes to authorize the Level A take of 1,507 and 
Level B take of 6,030 harbor seals.

                          Table 12--Calculation of the Number of Harbor Seal Exposures
----------------------------------------------------------------------------------------------------------------
                                                                                    Total pile
                                                                                   driving days
                                                                     Estimated       per month     Total number
                              Month                               seals per work     (includes     of requested
                                                                        day           upland           takes
                                                                                     driving)
----------------------------------------------------------------------------------------------------------------
June 2018.......................................................         Seals not expected to be present.
July 2018.......................................................         Seals not expected to be present.
August 2018.....................................................         Seals not expected to be present.
September 2018..................................................         Seals not expected to be present.

[[Page 18794]]

 
October 2018....................................................         Seals not expected to be present.
                                                                 -----------------------------------------------
November 2018...................................................             0.8              27              22
December 2018...................................................            20.8              24             499
January 2019....................................................              48              42           2,016
February 2019...................................................              96              42           4,032
March 2019......................................................              88              10             968
----------------------------------------------------------------------------------------------------------------

Gray Seals

    The number of gray seals potentially exposed to Level B harassment 
in the project area was calculated using the same methodology was used 
to estimate harbor seal exposures. Survey data recording gray seal 
observations was collected by the U.S. Navy at the portal islands from 
2014 through 2016 (Rees et al., 2016). Potential gray seal exposures 
were calculated as the number of potential seals per pile driving day 
(8 hours) multiplied by the number of pile driving days per month. The 
anticipated numbers of monthly exposures as shown in Table 13 were 
summed. Therefore, NMFS proposes to authorize take of 67 gray seals by 
Level B harassment. The Level A isopleths for gray seals are identical 
to those for harbor seals. Similarly, with a shutdown zone of 50 
meters, NMFS proposes to authorize the Level A take of 20 percent of 
gray seals. Therefore, NMFS proposes to authorize the Level A take of 
13 and Level B take of 54 gray seals.

                           Table 13--Calculation for the Number of Gray Seal Exposures
----------------------------------------------------------------------------------------------------------------
                                                                                    Total pile
                                                                                   driving days
                                                                     Estimated       per month      Harbor seal
                              Month                               seals per work     (includes         takes
                                                                        day           upland
                                                                                     driving)
----------------------------------------------------------------------------------------------------------------
June 2018.......................................................         Seals not expected to be present.
July 2018.......................................................         Seals not expected to be present.
August 2018.....................................................         Seals not expected to be present.
September 2018..................................................         Seals not expected to be present.
October 2018....................................................         Seals not expected to be present.
                                                                 -----------------------------------------------
November 2018...................................................               0              27               0
December 2018...................................................               0              24               0
January 2019....................................................               0              42               0
February 2019...................................................             1.6              42              67
March 2019......................................................               0              11               0
----------------------------------------------------------------------------------------------------------------

    Table 14 provides a summary of proposed authorized Level B takes as 
well as the percentage of a stock or population proposed for take.

                    Table 14--Proposed Authorized Take and Percentage of Stock or Population
----------------------------------------------------------------------------------------------------------------
                                                                     Proposed        Proposed
                Species                           Stock             authorized      authorized        Percent
                                                                   Level A takes   Level B takes    population
----------------------------------------------------------------------------------------------------------------
Humpback whale........................  Gulf of Maine...........  ..............               5            0.61
Bottlenose dolphin....................  WNA Coastal, Northern     ..............           1,804              16
                                         Migratory.
                                        WNA Coastal, Southern     ..............           1,804              20
                                         Migratory.
                                        NNCES...................  ..............             100              12
Harbor porpoise.......................  Gulf of Maine/Bay of                   4               6           <0.01
                                         Fundy.
Harbor seal...........................  Western North Atlantic..           1,507           6,030              10
Gray seal.............................  Western North Atlantic..              13              54           <0.01
----------------------------------------------------------------------------------------------------------------

Proposed Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting such 
activity or other means

[[Page 18795]]

of effecting the least practicable adverse impact upon the affected 
species or stocks and their habitat (50 CFR 216.104(a)(11)
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned) the likelihood of effective implementation (probability 
implemented as planned); and
    (2) the practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The following mitigation measures are proposed in the IHA:
     Pile Driving Delay/Shutdown Zone--For in-water heavy 
machinery work (using, e.g., standard barges, tug boats, barge-mounted 
excavators, or clamshell equipment used to place or remove material), a 
minimum 10 meters shutdown zone shall be implemented. If a marine 
mammal comes within 10 meters of such operations, operations shall 
cease and vessels shall reduce speed to the minimum level required to 
maintain steerage and safe working conditions. This type of work could 
include (but is not limited to) the following activities: (1) Vibratory 
pile driving; (2) movement of the barge to the pile location; (3) 
positioning of the pile on the substrate via a crane (i.e., stabbing 
the pile); or (4) removal of the pile from the water column/substrate 
via a crane (i.e., deadpull).
     Non-authorized Take Prohibited--If a species for which 
authorization has not been granted (e.g., North Atlantic right whale, 
fin whale, harbor porpoise) or a species for which authorization has 
been granted but the authorized takes are met, is observed approaching 
or within the Level B Isopleth, pile driving and removal activities 
must shut down immediately using delay and shut-down procedures. 
Activities must not resume until the animal has been confirmed to have 
left the area or an observation time period of 15 minutes has elapsed.
     Use of Impact Installation--During pile installation of 
hollow steel piles, an impact hammer rather than a vibratory hammer 
will be used to reduce the duration of pile driving decrease the ZOI 
for marine mammals.
     Cushion Blocks--Use of cushion blocks will be required 
during impact installation. Cushion blocks reduce source levels and, by 
association, received levels, although exact decreases in sound levels 
are unknown.
     Use of Bubble Curtain--An encased bubble curtain will be 
used for impact installation of plumb round piles at water depths 
greater than 3 m (10 ft). Bubble curtains will not function effectively 
in shallower depths.
     Soft-Start--The use of a soft start procedure is believed 
to provide additional protection to marine mammals by warning or 
providing a chance to leave the area prior to the hammer operating at 
full capacity, and typically involves a requirement to initiate sound 
from the hammer at reduced energy followed by a waiting period. A soft-
start procedure will be used for impact pile driving at the beginning 
of each day's in-water pile driving or any time impact pile driving has 
ceased for more than 30 minutes. The CTJV will start the bubble curtain 
prior to the initiation of impact pile driving. The contractor will 
provide an initial set of strikes from the impact hammer at reduced 
energy, followed by a 30-second waiting period, then two subsequent 
sets.
     Establishment of Additional Shutdown Zones and Monitoring 
Zones--For all impact and vibratory pile driving shutdown and 
monitoring zones will be established and monitored.
     CTJV will establish a shutdown zone of 200 meters for 
common dolphins and harbor porpoises and 50 meters for harbor and gray 
seals. The shutdown zones for humpback whales are depicted in Table 16.
     For all impact and vibratory pile driving shutdown and 
monitoring zones will be established and monitored. Level B zones are 
shown in Table 15.

Table 15--Radial Distance (Meters) From Pile Driven to Level B Isopleths
                       for Cetaceans and Pinnipeds
------------------------------------------------------------------------
                                               Radial distance  (m)
      Hammer type driving scenario       -------------------------------
                                             Island 1        Island 2
------------------------------------------------------------------------
Impact (battered).......................           1,585           1,585
Impact with Bubble Curtain..............             350             350
Vibratory...............................           1,850           1,850
Impact w/Bubble Curtain (plumb) at PI 1              540             540
 and PI 2 simultaneous..................
Impact w/Bubble Curtain (plumb) at PI 1              340           1,850
 and Vibratory at PI 2 simultaneous.....
Vibratory at PI 1 and Impact w/Bubble              1,850             340
 Curtain (plumb) at PI 2 simultaneous...
------------------------------------------------------------------------

     The Level A zones will depend on the number of piles 
driven and the presence of marine mammals per 24-hour period. Up to 3 
battered piles or 8 plumb steel piles will be driven per 24-hour period 
using the following adaptive monitoring approach. Monitoring will begin 
each day using the three-pile Level A zone for battered piles (or 
eight-pile zone for plumb piles). If after the first pile is driven, no 
marine mammals have been observed in the Level A zone, then the Level A 
zone will reduce to the two-pile zone. If no marine mammals are 
observed within the two-pile shutdown zone during the driving of the 
second pile, then the Level A zone will reduce to the one-pile zone. 
However, if a mammal is observed approaching or entering the three-pile 
Level A zone during the driving of the first pile, then the three-pile 
Level A zone will be monitored for the remainder of pile driving 
activities for that day. Likewise, if a marine mammal is observed 
within the two-pile but not the three-pile Level A zone, then the two-
pile Level A zone will be monitored for the remainder of pile driving 
activities for that day. The same protocol will be followed for 
installation of up to 8 plumb piles per day.

[[Page 18796]]

    The Level A isopleths for all authorized species are shown in Table 
16. Isopeths associated with low-frequency cetaceans will signify 
shutdown zones.for humpback and fin whales.

     Table 16--Radial Distance (Meters) From Pile Driven to PTS Zones for Cetaceans and Phocid Pinnipeds for
                                        Scenarios Involving Impact Hammer
----------------------------------------------------------------------------------------------------------------
                                                                                                 Simultaneous
                                                               Impact hammer   Impact hammer  driving--vibratory
                                               Impact hammer    with bubble     with bubble    hammer and impact
   Class of marine mammals     Piles per day     (battered        curtain         curtain     hammer with bubble
                                                   pile)       (plumb pile)    simultaneous     curtain (plumb
                                                                               (plumb pile)          pile)
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans*....               8             N/A           860.6           1,363             860.6
                                           7             N/A           787.3           1,247             787.3
                                           6             N/A           710.4           1,125             710.4
                                           5             N/A           629.1             997             629.1
                                           4             N/A           542.1             859             542.1
                                           3         2,077.2           447.5             709             447.5
                                           2         1,585.2           341.5             541             341.5
                                           1           998.6           215.1             341             215.1
Mid-Frequency Cetaceans.....               8             N/A            30.6              48              30.6
                                           7             N/A            28.0              44              28.0
                                           6             N/A            25.3              40              25.3
                                           5             N/A            22.4              35              22.4
                                           4             N/A            19.3              30              19.3
                                           3            73.9            15.9              25              15.9
                                           2            56.4            12.1              19              12.1
                                           1            35.5             7.7            12.1               7.7
High Frequency Cetaceans....               8             N/A         1,025.1           1,624           1,025.1
                                           7             N/A           937.8          1,4861             937.8
                                           6             N/A           846.2           1,341             846.2
                                           5             N/A           749.4           1,187             749.4
                                           4             N/A           645.8           1,023             645.8
                                           3         2,474.3           533.1             844             533.1
                                           2         1,888.3           406.8             644             406.8
                                           1         1,189.5           256.3             406             256.3
Phocid Pinnipeds............               8             N/A           460.5             729             460.5
                                           7             N/A           412.3             667             412.3
                                           6             N/A           380.2             602             380.2
                                           5             N/A           336.7             533             336.7
                                           4             N/A           290.1             459             290.1
                                           3         1,111.6           239.5             379             239.5
                                           2           848.3           182.8             289             182.8
                                           1           534.4           115.1             182             115.1
----------------------------------------------------------------------------------------------------------------
* These isopleths serve as shutdown zones for all large whales, including humpback and fin whales.

    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

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

[[Page 18797]]

Visual Monitoring

    The following visual monitoring measures are proposed in the IHA:
     Pre-activity monitoring shall take place from 30 minutes 
prior to initiation of pile driving activity and post-activity 
monitoring shall continue through 30 minutes post-completion of pile 
driving activity. Pile driving may commence at the end of the 30-minute 
pre-activity monitoring period, provided observers have determined that 
the shutdown zone is clear of marine mammals, which includes delaying 
start of pile driving activities if a marine mammal is sighted in the 
zone.
     If a marine mammal approaches or enters the shutdown zone 
during activities or pre-activity monitoring, all pile driving 
activities at that location shall be halted or delayed, respectively. 
If pile driving is halted or delayed due to the presence of a marine 
mammal, the activity may not resume or commence until either the animal 
has voluntarily left and been visually confirmed beyond the shutdown 
zone and 15 minutes have passed without re-detection of the animal. 
Pile driving activities include the time to install or remove a single 
pile or series of piles, as long as the time elapsed between uses of 
the pile driving equipment is no more than thirty minutes.
     Monitoring distances, in accordance with the identified 
shutdown zones, Level A zones and Level B zones, will be determined by 
using a range finder, scope, hand-held global positioning system (GPS) 
device or landmarks with known distances from the monitoring positions.
     Monitoring locations will be based on land both at Portal 
Island No. 1 and Portal Island No. 2 during simultaneous driving. 
During non-simultaneous a single monitoring location will be identified 
on the Portal Island with pile driving activity.
     Monitoring will be continuous unless the contractor takes 
a break longer than 2 hours from active pile and sheet pile driving, in 
which case, monitoring will be required 30 minutes prior to restarting 
pile installation.
     If marine mammals are observed, their location within the 
zones, and their reaction (if any) to pile activities will be 
documented.
     If weather or sea conditions restrict the observer's 
ability to observe, or become unsafe, pile installation will be 
suspended until conditions allow for monitoring to resume.
     For in-water pile driving, under conditions of fog or poor 
visibility that might obscure the presence of a marine mammal within 
the shutdown zone, the pile in progress will be completed and then pile 
driving suspended until visibility conditions improve.
     Monitoring of pile driving shall be conducted by qualified 
PSOs (see below), who shall have no other assigned tasks during 
monitoring periods. CVTJV shall adhere to the following conditions when 
selecting observers:
    (1) Independent PSOs shall be used (i.e., not construction 
personnel).
    (2) At least one PSO must have prior experience working as a marine 
mammal observer during construction activities.
    (3) Other PSOs may substitute education (degree in biological 
science or related field) or training for experience.
    (4) CTJV shall submit PSO CVs for approval by NMFS.
     CTJV will ensure that observers have the following 
additional qualifications:
    (1) Ability to conduct field observations and collect data 
according to assigned protocols.
    (2) Experience or training in the field identification of marine 
mammals, including the identification of behaviors.
    (3) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations.
    (4) Writing skills sufficient to prepare a report of observations 
including but not limited to the number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates, times, and reason for implementation of mitigation 
(or why mitigation was not implemented when required); and marine 
mammal behavior.
    (5) Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. It will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated marine 
mammal observation data sheets. Specifically, the report must include:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Deviation from initial proposal in pile numbers, pile 
types, average driving times, etc.
     Weather parameters (e.g., percent cover, visibility);
     Water conditions (e.g., sea state, tide state);
     For each marine mammal sighting:
    (1) Species, numbers, and, if possible, sex and age class of marine 
mammals;
    (2) Description of any observable marine mammal behavior patterns, 
including bearing and direction of travel and distance from pile 
driving activity;
    (3) Location and distance from pile driving activities to marine 
mammals and distance from the marine mammals to the observation point;
    (4) Estimated amount of time that the animals remained in the Level 
A Level B zone.
     Description of implementation of mitigation measures 
within each monitoring period (e.g., shutdown or delay); and
     Other human activity in the area.
     A summary of the following:
    (1) Total number of individuals of each species detected within the 
Level A and Level B Zone, and estimated as taken if correction factor 
is applied.
    (2) Daily average number of individuals of each species 
(differentiated by month as appropriate) detected within the Level A 
and Level B Zone, and estimated as taken, if correction factor is 
applied.
    If no comments are received from NMFS within 30 days, the draft 
final report will constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury, serious injury or mortality, CTJV would 
immediately cease the specified activities and report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, and the New England/Mid-Atlantic Regional Stranding 
Coordinator. The report would include the following information:
     Description of the incident;
     Environmental conditions (e.g., Beaufort sea state, 
visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with CTJV to 
determine what is necessary to

[[Page 18798]]

minimize the likelihood of further prohibited take and ensure MMPA 
compliance. CTJV would not be able to resume their activities until 
notified by NMFS via letter, email, or telephone.
    In the event that CTJV discovers an injured or dead marine mammal, 
and the lead PSO determines that the cause of the injury or death is 
unknown and the death is relatively recent (e.g., in less than a 
moderate state of decomposition as described in the next paragraph), 
CTJV would immediately report the incident to the Chief of the Permits 
and Conservation Division, Office of Protected Resources, NMFS, and the 
NMFS New England/Mid-Atlantic Regional Stranding Coordinator. The 
report would include the same information identified in the paragraph 
above. Activities would be able to continue while NMFS reviews the 
circumstances of the incident. NMFS would work with CTJV to determine 
whether modifications in the activities are appropriate.
    In the event that CTJV discovers an injured or dead marine mammal 
and the lead PSO determines that the injury or death is not associated 
with or related to the activities authorized in the IHA (e.g., 
previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), CTJV would report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, and the NMFS New England/Mid-Atlantic Regional 
Stranding Coordinator, within 24 hours of the discovery. CTJV would 
provide photographs or video footage (if available) or other 
documentation of the stranded animal sighting to NMFS and the Marine 
Mammal Stranding Network.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    CTJV's planned pile driving activities are highly localized. Only a 
relatively small portion of the Chesapeake Bay may be affected. The 
project is not expected to have significant adverse effects on marine 
mammal habitat. No important feeding and/or reproductive areas for 
marine mammals are known to be near the project area. Project-related 
activities may cause some fish to leave the area of disturbance, thus 
temporarily impacting marine mammals' foraging opportunities in a 
limited portion of their foraging range, but because of the relatively 
small impacted area of the habitat range utilized by each species that 
may be affected, the impacts to marine mammal habitat are not expected 
to cause significant or long-term negative consequences.
    A limited number of animals could experience Level A harassment in 
the form of PTS if they remain within the Level A harassment zone 
during certain impact driving scenarios. The sizes of the Level A zones 
are dependent on the number of steel piles driven in a 24-hour period. 
Up to 8 steel plumb piles or 3 steel battered piles could be driven in 
a single day, which would result in a relatively large Level A zones. 
(If fewer piles are driven per day then the Level A zones would be 
smaller) . However, an animal would have to be within the Level A zones 
during the driving of all 8 plumb or 3 battered piles. This is 
unlikely, as marine mammals tend to move away from sound sources. 
Furthermore, the degree of injury is expected to be mild and is not 
likely to affect the reproduction or survival of the individual 
animals. It is expected that, if hearing impairments occurs, most 
likely the affected animal would lose a few dB in its hearing 
sensitivity, which in most cases is not likely to affect its survival 
and recruitment.
    Exposures to elevated sound levels produced during pile driving 
activities may cause behavioral responses by an animal, but they are 
expected to be mild and temporary. Effects on individuals that are 
taken by Level B harassment, on the basis of reports in the literature 
as well as monitoring from other similar activities, will likely be 
limited to reactions such as increased swimming speeds, increased 
surfacing time, or decreased foraging (if such activity were occurring) 
(e.g., Thorson and Reyff, 2006; Lerma, 2014). Most likely, individuals 
will simply move away from the sound source and be temporarily 
displaced from the areas of pile driving, although even this reaction 
has been observed primarily only in association with impact pile 
driving. These reactions and behavioral changes are expected to subside 
quickly when the exposures cease. The pile driving activities analyzed 
here are similar to, or less impactful than, numerous construction 
activities conducted in numerous other locations on the east coast, 
which have taken place with no reported injuries or mortality to marine 
mammals, and no known long-term adverse consequences from behavioral 
harassment. Repeated exposures of individuals to levels of sound that 
may cause Level B harassment are unlikely to result in permanent 
hearing impairment or to significantly disrupt foraging behavior. 
Furthermore. Level B harassment will be reduced through use of 
mitigation measures described herein.
    CTJV will employ noise attenuating devices (i.e., bubble curtains, 
pile caps) during impact driving of plumb steel piles. During impact 
driving of both plumb and battered piles, implementation of soft start 
procedures and monitoring of established shutdown zones will be 
required, significantly reduces any possibility of injury. Given 
sufficient notice through use of soft start (for impact driving), 
marine mammals are expected to move away from a sound source. PSOs will 
be stationed on a portal island whenever pile driving operations are 
underway at that island. The portal island locations provide a 
relatively clear view of the shutdown zones as well as monitoring 
zones. These factors will limit exposure of animals to noise levels 
that could result in injury.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated;
     The area of potential impacts is highly localized;

[[Page 18799]]

     No adverse impacts to marine mammal habitat;
     The absence of any significant habitat within the project 
area, including rookeries, or known areas or features of special 
significance for foraging or reproduction;
     Anticipated incidents of Level A harassment would likely 
be mild;
     Anticipated incidents of Level B harassment consist of, at 
worst, temporary modifications in behavior; and
     The anticipated efficacy of the required mitigation 
measures in reducing the effects of the specified activity.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Section 101(a)(5)(D) of the MMPA for specified 
activities other than military readiness activities. The MMPA does not 
define small numbers and so, in practice, where estimated numbers are 
available, NMFS compares the number of individuals taken to the most 
appropriate estimation of abundance of the relevant species or stock in 
our determination of whether an authorization is limited to small 
numbers of marine mammals. Additionally, other qualitative factors may 
be considered in the analysis, such as the temporal or spatial scale of 
the activities.
    NMFS has preliminary determined that the estimated Level B take of 
humpback whale is 0.61 percent of the Gulf of Maine stock ; take of 
harbor seals is 10 percent of the Western North Atlantic stock; and 
take of gray seals is <0.01 percent of the Western North Atlantic 
stock. Estimated take of bottlenose dolphins (3,708), with 100 takes 
accruing to the NNCES stock and no more than half (1,804) of the 
remaining takes accruing to either of two migratory coastal stocks 
represents 12 percent of the NCCES stock (population 823), 16 percent 
of the Western North Atlantic northern migratory coastal stock (pop. 
11,548) and 20 percent of the Western North Atlantic southern migratory 
coastal stock (pop. 9,173). Additionally, some number of the 
anticipated takes are likely to be repeat sightings of the same 
individual, lowering the number of individuals taken.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Endangered Species Act (ESA)

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

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to CTJV for conducting pile driving and removal activities 
as part of the PTST project between June 1, 2018 and March 31, 2019, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. This section contains a draft of the IHA 
itself. The wording contained in this section is proposed for inclusion 
in the IHA (if issued).
    1. This Incidental Harassment Authorization (IHA) is valid from 
June 1, 2018 through May 31, 2019. This IHA is valid only for pile 
driving and extraction activities associated with the PTST project.
    2. General Conditions.
    (a) A copy of this IHA must be in the possession of CTJV, its 
designees, and work crew personnel operating under the authority of 
this IHA.
    (b) The species authorized for taking are of harbor seal (Phoca 
vitulina), gray seal (Halichoerus grypus), bottlenose dolphin (Tursiops 
spp.), harbor porpoise (Phocoena phocoena) and humpback whale 
(Megaptera novaeangliae).
    (c) The taking, by Level A and Level B harassment, is limited to 
the species listed in condition 2(b). See Table 14 for number of takes 
authorized.
    (d) The take of any other species not listed in condition 2(b) of 
marine mammal is prohibited and may result in the modification, 
suspension, or revocation of this IHA.
    (e) CTJV shall conduct briefings between construction supervisors 
and crews, marine mammal monitoring team, acoustical monitoring team 
prior to the start of all pile driving activities, and when new 
personnel join the work, in order to explain responsibilities, 
communication procedures, marine mammal monitoring protocol, and 
operational procedures.
    3. Mitigation Measures.
    The holder of this Authorization is required to implement the 
following mitigation measures:
    (a) Time Restrictions--For all in-water pile driving activities, 
CTJV shall operate only during daylight hours.
    (b) Use of Bubble Curtain.
    (i) CTJV shall employ an encased bubble curtain during impact pile 
driving of plumb steel piles in water depths greater than 3 m (10 ft).
    (c) Use of Soft-Start.--CTJV shall use soft start techniques when 
impact pile driving. Soft start requires contractors to provide an 
initial set of strikes at reduced energy, followed by a thirty-second 
waiting period, then two subsequent reduced energy strike sets. Soft 
start shall be implemented at the start of each day's impact pile 
driving and at any time following cessation of impact pile driving for 
a period of thirty minutes or longer.
    (d) Use of cushion blocks shall be required during impact 
installation.
    (e) Establishment of Shutdown Zones.
    (i) CTJV shall establish a shutdown zone of 200 meters harbor 
porpoise and common dolphin.
    (ii) CTJV shall establish a shutdown zone of 50 meters for harbor 
seals.
    (iii) CTJV shall establish shutdown zones for large whales (i.e. 
humpback, fin whale) according to low-frequency isopleths provided in 
Table 16.
    (iv) If a marine mammal comes within or approaches the shutdown 
zone, pile driving operations shall cease.

[[Page 18800]]

    (v) Pile driving and removal operations shall restart once the 
marine mammal is visibly seen leaving the zone or after 15 minutes have 
passed with no sightings.
    (vi) For in-water heavy machinery work (using, e.g., standard 
barges, tug boats, barge-mounted excavators, or clamshell equipment 
used to place or remove material), a minimum 10 meters shutdown zone 
shall be implemented. If a marine mammal comes within 10 meters of such 
operations, operations shall cease and vessels shall reduce speed to 
the minimum level required to maintain steerage and safe working 
conditions. This type of work could include (but is not limited to) the 
following activities: (1) Vibratory pile driving; (2) movement of the 
barge to the pile location; (3) positioning of the pile on the 
substrate via a crane (i.e., stabbing the pile); or (4) removal of the 
pile from the water column/substrate via a crane (i.e., deadpull).
    (vii) Shutdown shall occur if a species for which authorization has 
not been granted or for which the authorized numbers of takes have been 
met approaches or is observed within the pertinent take zone.
    (viii) If a marine mammal approaches or enters the shutdown zone 
during activities or pre-activity monitoring, all pile driving 
activities at that location shall be halted or delayed, respectively. 
If pile driving is halted or delayed due to the presence of a marine 
mammal, the activity may not resume or commence until either the animal 
has voluntarily left and been visually confirmed beyond the shutdown 
zone and 15 minutes have passed without re-detection of the animal. 
Pile driving activities include the time to install or remove a single 
pile or series of piles, as long as the time elapsed between uses of 
the pile driving equipment is no more than thirty minutes.
    (ix) If a species for which authorization has not been granted, or 
a species for which authorization has been granted but the authorized 
takes are met, is observed approaching or within the designated Level B 
Isopleth pile driving and removal activities must shut down immediately 
using delay and shut-down procedures. Activities must not resume until 
the animal has been confirmed to have left the area or the observation 
time period, as indicated in 3(e)(v) above, has elapsed.
    (f) Establishment of Level A and Level B Harassment Zones.
    (i) CTJV shall establish and monitor a level B zone according to 
values depicted in Table 15 during all driving activities.
    (ii) CTJV shall use an adaptive approach to establish Level A zones 
during impact pile driving.
    (1) The number of plumb piles planned for a given day determines 
initial Level A zone size as shown in Table 16.
    (2) If after the first pile is driven, no marine mammals have been 
observed in the Level A zone, then the Level A zone shall be reduced to 
the Level A zone associated with the next lowest number of piles driven 
per day. If no marine mammals are observed within that zone, the Level 
A zone shall again be reduced to the next lowest number of piles per 
day. This trend shall continue until an animal is seen approaching or 
entering a specified shutdown zone.
    (3) If Level A take does occur, the Level A zone size in effect 
during the initial Level A take shall remain in place for the remainder 
of the day.
    (4) Pile driving activities shall not be conducted when weather/
observer conditions do not allow for adequate sighting of marine 
mammals within the monitoring zone (e.g. lack of daylight/fog).
    (5) In the event of conditions that prevent the visual detection of 
marine mammals, impact pile driving shall be curtailed, but pile in 
progress shall be completed and then pile driving suspended until 
visibility conditions improve.
    4. Monitoring
    The holder of this Authorization is required to conduct visual 
marine mammal monitoring during pile driving activities.
    (a) Visual Marine Mammal Observation--CTJV shall collect sighting 
data and behavioral responses to pile driving for marine mammal species 
observed in the region of activity during the period of activity. 
Visual monitoring shall include the following:
    (i) Pre-activity monitoring shall take place from 30 minutes prior 
to initiation of pile driving activity and post-activity monitoring 
shall continue through 30 minutes post-completion of pile driving 
activity. Pile driving may commence at the end of the 30-minute pre-
activity monitoring period, provided observers have determined that the 
shutdown zone is clear of marine mammals, which includes delaying start 
of pile driving activities if a marine mammal is sighted in the zone.
    (ii) Protected Species Observers (PSOs) shall be positioned at the 
best practicable vantage points, taking into consideration security, 
safety, and space limitations. The PSOs shall be stationed in a 
location that shall provide adequate visual coverage for the shutdown 
zone and monitoring zones.
    (iii) Monitoring locations shall be based on land both at Portal 
Island No. 1 and Portal Island No. 2 during simultaneous driving. 
During non-simultaneous driving a single monitoring location shall be 
identified on the Portal Island with pile driving activity.
    (iv) Monitoring distances, in accordance with the identified 
shutdown zones, Level A zones and Level B zones, shall be determined by 
using a range finder, scope, hand-held global positioning system (GPS) 
device or landmarks with known distances from the monitoring positions
    (v) CTJV shall adhere to the following observer qualifications:
    (1) Independent PSOs shall be used (i.e., not construction 
personnel).
    (2) At least one PSO must have prior experience working as a marine 
mammal observer during construction activities.
    (3) Other PSOs may substitute education (degree in biological 
science or related field) or training for experience.
    (4) CTJV shall submit PSO CVs for approval by NMFS.
    (vi) CTJV shall ensure that observers have the following additional 
qualifications:
    (1) Ability to conduct field observations and collect data 
according to assigned protocols.
    (2) Experience or training in the field identification of marine 
mammals, including the identification of behaviors.
    (3) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations.
    (4) Writing skills sufficient to prepare a report of observations 
including but not limited to the number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates, times, and reason for implementation of mitigation 
(or why mitigation was not implemented when required); and marine 
mammal behavior.
    (5) Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    5. Reporting
    (a) A draft marine mammal monitoring report shall be submitted to 
NMFS within 90 days after the completion of pile driving and removal 
activities or a minimum of 60 days prior to any subsequent IHAs. A 
final report shall be prepared and submitted to the

[[Page 18801]]

NMFS within 30 days following receipt of comments on the draft report 
from the NMFS. If no comments are received from NMFS within 30 days, 
the draft final report shall constitute the final report. If comments 
are received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.
    (b) The report shall include an overall description of work 
completed, a narrative regarding marine mammal sightings, and 
associated marine mammal observation data sheets. Specifically, the 
report must include:
    (i) Date and time that monitored activity begins or ends;
    (ii) Construction activities occurring during each observation 
period;
    (iii) Weather parameters (e.g., percent cover, visibility);
    (iv) Water conditions (e.g., sea state, tide state);
    (v) Total number of individuals of each species detected within the 
Level A and Level B Zone, and estimated taken if a correction factor is 
used;
    (vi) Daily average number of individuals of each species 
(differentiated by month as appropriate) detected within the Level A 
and Level B Zone, and estimated as taken if correction factor is used;
    (vii) Each marine mammal sighting shall include the following:
    (1) Species, numbers, and, if possible, sex and age class of marine 
mammals;
    (2) Description of any observable marine mammal behavior patterns, 
including bearing and direction of travel and distance from pile 
driving activity;
    (3) Location and distance from pile driving activities to marine 
mammals and distance from the marine mammals to the observation point;
    (4) Estimated amount of time that the animals remained in the Level 
A and/or Level B zone;
    (5) Description of implementation of mitigation measures within 
each monitoring period (e.g., shutdown or delay);
    (6) Other human activity in the area.
    (c) In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury, serious injury or mortality, CTJV would 
immediately cease the specified activities and report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, and the New England/Mid-Atlantic Regional Stranding 
Coordinator. The report would include the following information:
    (i) Description of the incident;
    (ii) Environmental conditions (e.g., Beaufort sea state, 
visibility);
    (iii) Description of all marine mammal observations in the 24 hours 
preceding the incident;
    (iv) Species identification or description of the animal(s) 
involved;
    (v) Fate of the animal(s); and
    (vi) 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 prohibited take. NMFS would work with CTJV to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. CTJV would not be able to 
resume their activities until notified by NMFS via letter, email, or 
telephone.
    (d) In the event that CTJV discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition as described in the next paragraph), 
CTJV would immediately report the incident to the Chief of the Permits 
and Conservation Division, Office of Protected Resources, NMFS, and the 
New England/Mid-Atlantic Regional Stranding Coordinator. The report 
would include the same information identified in the paragraph above. 
Activities would be able to continue while NMFS reviews the 
circumstances of the incident. NMFS would work with CTJV to determine 
whether modifications in the activities are appropriate.
    (e) In the event that CTJV discovers an injured or dead marine 
mammal and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), CTJV would report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, and the NMFS New England/Mid-Atlantic Regional 
Stranding Coordinator, within 24 hours of the discovery. CTJV would 
provide photographs or video footage (if available) or other 
documentation of the stranded animal sighting to NMFS and the Marine 
Mammal Stranding Network.
    6. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein, or if 
NMFS determines the authorized taking is having more than a negligible 
impact on the species or stock of affected marine mammals.

Request for Public Comments

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

Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2018-09032 Filed 4-27-18; 8:45 am]
 BILLING CODE 3510-22-P