Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Transco Lower New York Bay Lateral (LNYBL) Natural Gas Pipeline Maintenance in Sandy Hook Channel, NJ, 84789-84808 [2023-26704]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 233 (Wednesday, December 6, 2023)]
[Notices]
[Pages 84789-84808]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-26704]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD407]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Transco Lower New York Bay Lateral 
(LNYBL) Natural Gas Pipeline Maintenance in Sandy Hook Channel, NJ

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

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

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SUMMARY: NMFS has received a request from Transcontinental Gas Pipe 
Line Company LLC (Transco), a subsidiary of Williams Partners L.P., for 
authorization to take marine mammals incidental to pile driving 
associated with the LNYBL Natural Gas Pipeline Maintenance in Sandy 
Hook Channel, New Jersey (NJ). Pursuant to the Marine Mammal Protection 
Act (MMPA), NMFS is requesting comments on its proposal to issue an 
incidental harassment authorization (IHA) to incidentally take marine 
mammals during the specified activities. NMFS is also requesting 
comments on a possible one-time, 1 year renewal that could be issued 
under certain circumstances and if all requirements are met, as 
described in Request for Public Comments at the end of this notice. 
NMFS will consider public comments prior to making any final decision 
on the issuance of the requested MMPA authorization and agency 
responses will be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than January 
5, 2024.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email to 
[email protected]. Electronic copies of the application and 
supporting documents, as well as a list of the references cited in this 
document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems accessing these documents, 
please call the contact listed above.

[[Page 84790]]

    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, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act 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: Kate Fleming, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

National Environmental Policy Act

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

Summary of Request

    On April 28, 2023, NMFS received a request from Transco for an IHA 
to take marine mammals incidental to pile driving activities associated 
with the LNYBL maintenance project in Sandy Hook Channel, NJ. On 
September 1, 2023 Transco submitted updates to the planned daily 
duration of pile driving and on October 27, 2023, Transco notified NMFS 
of changes to project timing. Following NMFS' review of the 
application, discussions between NMFS and Transco, and reanalysis 
following the aforementioned project changes, the application was 
deemed adequate and complete on November 2, 2023. Transco's request is 
for take of 11 species of marine mammals, by Level B harassment and, 
for a subset of 3 of these species, Level A harassment. Neither Transco 
nor NMFS expect serious injury or mortality to result from this 
activity and, therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    Transco is proposing construction activities to stabilize the LNYBL 
natural gas pipeline that extends 34 miles (mi) [55 kilometers (km)] in 
Raritan Bay, Lower New York Bay, and the Atlantic Ocean from Morgan, NJ 
to Long Beach, New York (NY). During routine monitoring of the existing 
LNYBL, Transco identified seven discrete sections of the gas pipeline 
with either limited cover or exposure resulting from dynamic 
conditions. The LNYBL maintenance project is the maintenance of 
pipeline sections with seven corresponding ``work areas'' that 
encompass all in-water temporary work spaces within NY and NJ where 
project-related activities may cause sediment disturbance. To stabilize 
the pipeline, Transco would place rock over the pipeline at seven 
distinct work areas. At Work Area 3, near Sandy Hook Channel, NJ, 
Transco would install 960 sheet piles to provide additional stability 
and protection, and to mitigate future seabed lowering and erosion 
along the north flank of Sandy Hook Channel. Proposed activities 
included as part of the project with potential to affect marine mammals 
include vibratory and impact pile driving of steel sheet piles at Work 
Area 3 on 80 days between June and September 2024. Other in-water work 
described above would not cause take of marine mammals.

Dates and Duration

    Pile driving activities are planned to occur between June 15 and 
September 15, 2024. Pile installation and removal activities are 
expected to take a total of 80 days. Additional in-water construction 
activities (i.e., rock placement) would occur through November 2024.

Specific Geographic Region

    The proposed pile driving activity will occur at Sandy Hook 
Channel, where Raritan Bay and Lower New York Bay meet, in NJ state 
waters (Figure 1) and adjacent to the northwest portion of the New York 
Bight. Leading to the Port of New York and New Jersey, these bays 
experience significant commercial and recreational vessel activity. The 
work area is subject to erosional forces associated with high tidal 
currents near Sandy Hook Peninsula resulting from sand deposition at 
the Sandy Hook landmass spit. Depths at Work Area 3 range from 5.3 
meters (m) [17.3 feet (ft)] to 10.6 m (34.8 ft). However, the 
harassment zones would extend 13.6 km (8.5 mi) and reach depths greater 
than 20 m (66 ft).

[[Page 84791]]

[GRAPHIC] [TIFF OMITTED] TN06DE23.085

Figure 1. Map illustrating the proposed project location in Sandy Hook 
Channel, NJ.

Detailed Description of the Specified Activity

    Transco plans to maintain the LNYBL, which is a 26-inch (in) [66 
centimeter (cm)] diameter concrete coated natural gas pipeline that 
extends 34 miles in Raritan Bay, Lower New York Bay, and the Atlantic 
Ocean from Morgan, NJ to Long Beach, NY. Transco plans to install 960 
36-in (91 cm) long sheet piles approximately 600 ft (183 m) north of 
Sandy Hook Channel, to establish a retaining wall approximately 18 ft 
(5.5 m) south of the pipeline that prevents the currents at Sandy Hook 
Channel from further eroding the underlying seabed. To reduce potential 
seabed erosion on the southern (channel) side of the sheet pile wall, 
armor rock placement will also be placed along the southern side of the 
sheet piles. The sheet piles will be installed using a barge-mounted 
vibratory hammer (vibro-hammer) and, when necessary, an impact hammer. 
A template will be fixed to the barge used for sheet pile installation, 
which will help position sheet piles and shorten the time needed for 
sheet pile installation compared to typical sheet pile installation 
methods. The sheet piles will be stored at a local port and will be 
brought out to the crane barge using supply barges with tugs. Sheet 
piles will be installed for approximately 2,400 ft (732 m). Each 
installed sheet pile will be surveyed for orientation to record the 
distance from the pipeline.
    Vibro-hammers continuously vibrate the sheet pile into the 
substrate until the desired depth is reached. A vibro-hammer uses 
spinning counterweights, causing the sheet pile to vibrate at a high 
speed. The vibrating sheet pile causes the soil underneath it to 
``liquefy'' and allow the sheet pile to move easily into or out of the 
sediment. Once refusal is reached with the vibratory hammer, Transco 
will switch to a hydraulic impact hammer to attain an acceptable depth. 
A representative hydraulic impact hammer that may be used is the IHC 
Hydrohammer S Series--specifically, the S-30, S-40, and S-70. The rams 
of these Hydrohammers range from 1.5 to 3.5 metric tons with maximum 
speeds from 50 to 65 blows per minute. Maximum obtainable energy for 
the largest of the three models (S-70) is 51,630 foot-pounds (70 
kilonewton meters) at its highest setting. The minimum rated energy for 
the smallest hammer (S-30) is 2,213 foot-pounds (3 kilonewton meters).
    Active sheet pile installation will occur during daylight hours on 
80 days; daily operational time for the vibro-hammer and impact hammer 
is expected to be 2 hours each, for a maximum total of 4 hours (table 
1). Rock placement will follow shortly after sheet pile installation at 
a given location while sheet piling continues at a nearby location.
    Transco also plans to place rock material over six additional 
discrete locations along the pipeline that are exposed or poorly 
covered (Work areas 1, 2, 4, 5, 6 and 7), totaling 26.52 acres), using 
barge or vessel mounted cranes with clamshell type buckets and 
multibeam sonar and/or ultra-short baseline beacons to support accurate 
placement. Only the pile driving activities at Work Area 3 have the 
potential to result in take of marine mammals, thus the rock placement 
components of the project, including vessel operations and rock 
placement validation equipment, are not discussed further in this 
document. Please refer to Transco's application for additional 
information about project components that are not expected to result in 
the incidental take of marine mammals.

[[Page 84792]]



                                                    Table 1--Pile Installation Methods and Durations
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                                                                                          Average
                                                                      Average piles      vibratory      Impact strikes  Estimated total      Days of
                     Pile type                      Number of piles      per day        duration per       per pile        number of       installation
                                                                                       pile (minutes)                   minutes per day    and removal
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36-inch sheet piles...............................             960               12               10              520              240               80
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    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. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and 
more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this activity, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS' 
SARs). While no serious injury or mortality is anticipated or proposed 
to be authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Atlantic and Gulf of Mexico SARs (Hayes et al., 2022; Hayes 
et al., 2023). All values presented in table 2 are the most recent 
available at the time of publication and are available online at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                              Table 2--Species Likely Impacted by the Specified Activities
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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\
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                                            Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals):
    Fin Whale.......................  Balaenoptera physalus..  Western N Atlantic.....  E, D, Y             6,802 (0.24, 5,573,            11        1.8
                                                                                                             2016).
    Humpback Whale..................  Megaptera novaeangliae.  Gulf of Maine..........  -, -, N             1,396.................         22      12.15
    Minke Whale.....................  Balaenoptera             Canadian Eastern         -, -, N             21,968 (0.31, 17,002,         170       10.6
                                       acutorostrata.           Coastal.                                     2016).
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                                                  Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Atlantic White-sided Dolphin....  Lagenorhynchus acutus..  Western N Atlantic.....  -, -, N             93,233 (0.71, 54,443,         544         27
                                                                                                             2016).
    Bottlenose Dolphin..............  Tursiops truncatus.....  Northern Migratory       -, -, Y             6,639, (0.41, 4,759,           48  12.2-21.5
                                                                Coastal.                                     2016).
                                                               Western North Atlantic   -, -, N             62,851 (0.23, 51,914,         519         28
                                                                Offshore.                                    2016).
    Common Dolphin..................  Delphinus delphis......  Western N Atlantic.....  -, -, N             172,974 (0.21,              1,452        390
                                                                                                             145,216, 2016).
    Atlantic Spotted Dolphin........  Stenella frontalis.....  Western N Atlantic.....  -, -, N             39,921 (0.27, 32,032,         320          0
                                                                                                             2016).
Family Phocoenidae (porpoises):
    Harbor Porpoise.................  Phocoena phocoena......  Gulf of Maine/Bay of     -, -, N             95,543 (0.31, 74,034,         851        164
                                                                Fundy.                                       2016).
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                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Harp Seal.......................  Pagophilus               Western N Atlantic.....  -, -, N             7.6M (UNK, 7.1M, 2019)    426,000    178,573
                                       groenlandicus.
    Harbor Seal.....................  Phoca vitulina.........  Western N Atlantic.....  -, -, N             61,336 (0.08, 57,637,       1,729        339
                                                                                                             2018).
    Gray Seal \4\...................  Halichoerus grypus.....  Western N Atlantic.....  -, -, N             27,300 (0.22, 22,785,       1,458      4,453
                                                                                                             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.

[[Page 84793]]

 
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\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, vessel strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\4\ This stock abundance estimate is only for the U.S. portion of this stock. The actual stock abundance, including the Canadian portion of the
  population, is estimated to be approximately 424,300 animals. The PBR value listed here is only for the U.S. portion of the stock, while M/SI reflects
  both the Canadian and U.S. portions.

    As indicated above, all 11 species (with 12 managed stocks) in 
table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. All species that could 
potentially occur in the proposed project areas are included in Table 
3-1 of the IHA application. North Atlantic right whale, short-finned 
pilot whale, and long-finned pilot whale could potentially occur in the 
area. However, the spatial and temporal occurrence of these species is 
rare, and the applicant would shut down pile driving if they enter the 
project area. In the case of North Atlantic right whale, the take 
estimation process resulted in calculated exposure of 0.5. Given the 
low likelihood of the exposure in concert with the proposed requirement 
to shut down pile driving activities upon observation at any distance, 
take is not expected to occur. As such, they are not discussed further.
    On August 1, 2022, NMFS announced proposed changes to the existing 
North Atlantic right whale vessel speed regulations to further reduce 
the likelihood of mortalities and serious injuries to endangered right 
whales from vessel collisions, which are a leading cause of the 
species' decline and a primary factor in an ongoing Unusual Mortality 
Event (UME) (87 FR 46921). Should a final vessel speed rule be issued 
and become effective during the effective period of this IHA (or any 
other MMPA incidental take authorization), the authorization holder 
would be required to comply with any and all applicable requirements 
contained within the final rule. Specifically, where measures in any 
final vessel speed rule are more protective or restrictive than those 
in this or any other MMPA authorization, authorization holders would be 
required to comply with the requirements of the rule. Alternatively, 
where measures in this or any other MMPA authorization are more 
restrictive or protective than those in any final vessel speed rule, 
the measures in the MMPA authorization would remain in place. These 
changes would become effective immediately upon the effective date of 
any final vessel speed rule and would not require any further action on 
NMFS's part.

Fin Whale

    Fin whales are common in waters of the U.S. Atlantic Exclusive 
Economic Zone, principally from Cape Hatteras northward (Hayes et al., 
2022). Fin whales are present north of 35-degree latitude in every 
season and are broadly distributed throughout the western North 
Atlantic for most of the year, though densities vary seasonally 
(Edwards et. al., 2015). Fin whales are often found in small groups of 
up five to seven individuals (NMFS 2023). Fin whales have been observed 
in the waters off the eastern end of Long Island, but are more common 
in deeper waters.
    While there is no active UME for fin whale, strandings and 
mortalities are occasionally reported in NJ and NY waters (Hayes et 
al., 2021, Newman et al., 2012). Between 2015 and 2019, only one fin 
whale mortality was recorded in the vicinity of the Project area with a 
vessel strike reported as the likely cause (Henry et al., 2022).

Humpback Whale

    Prior to 2016, humpback whales were listed under the ESA as an 
endangered species worldwide. Following a 2015 global status review 
(Bettridge et al., 2015), NMFS delineated 14 Distinct Population 
Segments (DPS) with different listing statuses (81 FR 62259, September 
8, 2016) pursuant to the ESA. The West Indies DPS, which is not listed 
under the ESA, is the only DPS of humpback whales that is expected to 
occur in the survey area.
    Humpback whale sightings and mortalities in the New York Bight have 
been increasing over the last decade (Brown 2022) including in the bays 
that intersect with the project area. Between 2011 and 2016, there have 
been at least 46 humpback whale sightings within Lower New York Bay, 
Upper New York Bay, and Raritan Bay (Brown et al., 2018). Most 
sightings occurred during the summer months (July to September), with 
no documented sightings in the winter (Brown et al., 2018). A total of 
617 humpback whale sightings were reported within the New York Bight 
based on data collected from 2011-2017 (Brown et al., 2018). During 
winter, the majority of humpback whales from North Atlantic feeding 
areas mate and calve in the West Indies, where spatial and genetic 
mixing among feeding groups occurs, though significant numbers of 
animals are found in mid- and high-latitude regions at this time and 
some individuals have been sighted repeatedly within the same winter 
season, indicating that not all humpback whales migrate south every 
winter (Clapham et al., 1993).
    Since January 2016, elevated humpback whale mortalities have 
occurred along the Atlantic coast from Maine (ME) to Florida. Partial 
or full necropsy examinations have been conducted on 45 percent of the 
202 known cases. Of the whales examined, about 40 percent had evidence 
of human interaction, either ship strike or entanglement. While a 
portion of the whales have shown evidence of pre-mortem vessel strike, 
this finding is not consistent across all whales examined and more 
research is needed. NOAA is consulting with researchers that are 
conducting studies on the humpback whale populations, and these efforts 
may provide information on changes in whale distribution and habitat 
use that could provide additional insight into how these vessel 
interactions occurred. Three previous UMEs involving humpback whales 
have occurred since 2000, in 2003, 2005, and 2006. More information is 
available at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-unusual-mortality-events.

Minke Whale

    Minke whales occur in temperate, tropical, and high-latitude 
waters. The Canadian East Coast stock can be found in the area from the 
western half of the Davis Strait (45[deg] W) to the Gulf of Mexico 
(Hayes et al., 2022). This species generally occupies waters less than 
100 m deep on the continental shelf. There appears to be a strong 
seasonal component to minke whale distribution. During spring and 
summer, they appear to be widely distributed from just east of Montauk 
Point, Long Island, northeast to Nantucket Shoals, and north towards 
Stellwagen Bank and Jeffrey's Ledge (CeTAP, 1982). During the fall, 
their range is much smaller and their abundance is reduced throughout 
their range (CeTAP, 1982).
    Since January 2017, elevated minke whale mortalities have occurred 
along the Atlantic coast from ME through South Carolina, with a total 
of 151 strandings recorded when this document was written. This event 
has been declared a UME though it is currently considered non-active 
with closure pending. Full or partial

[[Page 84794]]

necropsy examinations were conducted on more than 60 percent of the 
whales. Preliminary findings in several of the whales have shown 
evidence of human interactions or infectious disease, but these 
findings are not consistent across all of the whales examined, so more 
research is needed. More information is available at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-unusual-mortality-events.

Atlantic White-Sided Dolphin

    The Atlantic white-sided dolphin occurs throughout temperate and 
sub-polar waters of the North Atlantic, most prominently in continental 
shelf waters to depths of approximately 100 m (330 ft) (Hayes et al., 
2022). Atlantic white-sided dolphins of the western North Atlantic 
stock inhabit waters from central west Greenland to North Carolina (NC) 
and as far east as the mid-Atlantic ridge (Hamazaki 2002; Doksaeter et 
al., 2008; Hayes et al., 2022). Seasonal shifts in abundance occur 
throughout the western North Atlantic region, where the dolphins appear 
to be more prevalent from Georges Bank to the lower Bay of Fundy from 
June through September. From October to December, they appear to occur 
at intermediate densities from southern Georges Bank to the southern 
Gulf of Maine (Payne et al., 1990; Hayes et al., 2022). Sightings of 
dolphins south of Georges Bank (Hudson Canyon in particular) occur 
year-round, but generally at lower densities (Hayes et al., 2022).
    Based on observations made during CeTAP surveys in 1982, Atlantic 
white-sided dolphins were found primarily east and north of Long Island 
and the project area. The Atlantic white-sided dolphins observed south 
of Long Island were farther offshore in the deeper water of the 
continental shelf proper and closer to the continental shelf slope. 
This species was largely absent from the overall region (Cape Hatteras, 
NC, to the Gulf of Maine) during the winter (CeTAP 1982).
    Historically, Atlantic white-sided dolphins have stranded along the 
coasts of NY and NJ. However, since 2015, no strandings have been 
reported in either state (Hayes et al., 2022). During 2013, two 
Atlantic white-sided dolphins stranded along the Long Island coast 
(RFMRP 2014) in March and May.
    Based on the known occurrence of this species in New England waters 
east and north of the Project area during the spring, summer, and fall, 
and the overall lack of presence throughout the region during the 
winter, it is possible that Atlantic white-sided dolphin could 
infrequently occur in the vicinity of the Project area during the in-
water maintenance period.

Bottlenose Dolphin

    There are two distinct bottlenose dolphin morphotypes in the 
western North Atlantic: The coastal and offshore forms (Hayes et al., 
2018). The two morphotypes are genetically distinct based upon both 
mitochondrial and nuclear markers (Hoelzel et al., 1998; Rosel et al., 
2009). The offshore form is distributed primarily along the outer 
continental shelf and continental slope in waters greater than 40 m 
from Georges Bank to the Florida Keys (Hayes et al., 2018). The 
Northern Migratory Coastal stock occupies coastal waters from the 
shoreline to approximately the 20-m isobath between Assateague, VA, and 
Long Island, NY during warm water months. The stock migrates in late 
summer and fall and, during cold water months (best described by 
January and February), occupies coastal waters from approximately Cape 
Lookout, NC, to the NC/VA border (Garrison et al., 2017). Based on the 
known distribution of the Northern Migratory Coastal stock, this stock 
could also occur in the vicinity of the project during the proposed 
project; however, Sandy Hook, NJ (southeast of Raritan Bay) represents 
the northern extent of the stock's range (Hayes et al., 2018).
    From 2014 to 2018, 50 bottlenose dolphins stranded in NY and 88 
stranded in NJ (Hayes et al., 2020). A significant number of strandings 
occurred in 2013, with 38 strandings in NY and 153 strandings in NJ. 
The stock identity of these strandings is highly uncertain and may 
include individuals from the coastal and offshore stocks (Hayes et al., 
2020). NMFS declared a UME for bottlenose dolphins in the mid-Atlantic 
region beginning in early July 2013 and ending March 2015. This UME 
included elevated numbers of strandings in NY, NJ, Delaware, Maryland, 
and VA. Incidental take of dolphins proposed for authorization here may 
be of either the offshore or northern coastal migratory stocks.

Common Dolphin

    The common dolphin is found world-wide in temperate to subtropical 
seas. In the North Atlantic, common dolphins are typically found over 
the continental shelf between the 100-m and 2,000-m isobaths and over 
prominent underwater topography and east to the mid-Atlantic Ridge 
(Doksaeter et al., 2008; Waring et al., 2008), but may be found in 
shallower shelf waters as well. Common dolphins occur primarily east 
and north of Long Island and may occur in the project area during all 
seasons (CeTAP, 1982). Between 2015 and 2019, 41 common dolphins 
stranded in NY and 14 stranded in NJ (Hayes et al., 2022).

Atlantic Spotted Dolphin

    Atlantic spotted dolphins are found in tropical and warm temperate 
waters ranging from southern New England, south to Gulf of Mexico and 
the Caribbean to Venezuela (Hayes et al., 2020). The Western North 
Atlantic stock regularly occurs in continental shelf waters south of 
Cape Hatteras and in continental shelf edge and continental slope 
waters north of this region (Hayes et al., 2020). There are two forms 
of this species, with the larger ecotype inhabiting the continental 
shelf and usually occurring inside or near the 200-m isobaths (Hayes et 
al., 2020). It has been suggested that the species may move inshore 
seasonally during the spring, but data to support this theory is 
limited (Caldwell and Caldwell, 1966; Fritts et al., 1983). No Atlantic 
spotted dolphins have been stranded along the NY or NJ coasts in recent 
years.

Harbor Porpoise

    Harbor porpoises occur from the coastline to deep waters (>1800 m; 
Westgate et al., 1998), although the majority of the population is 
found over the continental shelf in waters less than 150 m (Hayes et 
al., 2022). In the project area, only the Gulf of Maine/Bay of Fundy 
stock of harbor porpoise may be present. This stock is found in U.S. 
and Canadian Atlantic waters and is concentrated in the northern Gulf 
of Maine and southern Bay of Fundy region in the summer, but they are 
widely dispersed from NJ to ME in the spring and fall (Hayes et al., 
2022). In the winter, intermediate densities of harbor porpoises can be 
found in waters off NJ to NC, and lower densities of harbor porpoises 
can be found in waters of NY to New Brunswick, Canada. In 2011, six 
sightings were recorded inside Long Island Sound with one sighting 
recorded just outside the Sound (NEFSC and SEFSC, 2011). Between 2011 
and 2015, 33 harbor porpoises stranded in NY and 17 stranded in NJ 
(Hayes et al., 2018). Additionally, between 2015 and 2019, 31 harbor 
porpoises stranded in NY and 32 stranded in NJ (Hayes et al., 2022).

Harp Seal

    Harp seals are highly migratory and occur throughout much of the 
North Atlantic and Arctic Oceans. Breeding occurs between late-February 
and April and adults then assemble on suitable pack ice to undergo the 
annual molt.

[[Page 84795]]

The migration then continues north to Arctic summer feeding grounds. 
Harp seal occurrence in the project area is considered rare. However, 
since the early 1990s, numbers of sightings and strandings have been 
increasing off the east coast of the United States from ME to NJ 
(Rubinstein 1994; Stevick and Fernald 1998; McAlpine 1999; Lacoste and 
Stenson 2000; Soulen et al., 2013). These extralimital appearances 
usually occur in January-May (Harris et al., 2002), when the western 
North Atlantic stock is at its most southern point of migration.
    Between 2011 and 2015, 78 harp seals stranded (mortalities) in NY 
and 22 stranded (mortalities) in NJ (Hayes et al., 2018). During 2013, 
eight harp seals stranded (mortalities and alive) on Long Island 
(RFMRP, 2014). All of those strandings occurred between January and 
June. Between 2015 and 2019, 86 harp seals stranded in NY and 15 
stranded in NJ (Hayes et al., 2022).
    As described above, elevated seal mortalities, including harp 
seals, occurred across ME, New Hampshire (NH) and Massachusetts (MA), 
and as far south as Virginia (VA), between July 2018 and March 2020. 
This event was declared a UME though it is currently non-active with 
closure pending, with phocine distemper virus identified as the main 
pathogen found in the seals. Information on this UME is available 
online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-unusual-mortality-events.

Harbor Seal

    Harbor seals are found in all nearshore waters of the North 
Atlantic and North Pacific Oceans and adjoining seas above about 
30[deg] N (Burns, 2009). In the western North Atlantic, harbor seals 
are year-round inhabitants of the coastal waters of eastern Canada and 
ME and occur seasonally along the coasts from southern New England to 
VA. Their presence in the region of the project area increases from 
October to March, when adults, sub-adults, and juveniles are expected 
to migrate south from ME. They return north to the coastal waters of ME 
and Canada in late spring (Katona et al., 1993). The closest known 
haulout sites for harbor seals in the vicinity of the project area are 
located 2.9 km (1.8 mi) southwest of the project site (Reynolds 2022) 
and 16.1 km (10 statute miles) east [Coastal Research and Education 
Society of Long Island (CRESLI) 2023], outside of the ensonified area. 
There are approximately 26 haulout locations around Long Island, and 
CRESLI has documented a total of 31,846 pinnipeds (primarily harbor 
seals) during surveys since 2006 (CRESLI 2023).
    Between July 2018 and March 2020, elevated numbers of harbor seal 
and gray seal mortalities occurred across ME, NH and MA. This event was 
declared a UME though it is currently non-active with closure pending. 
Stranded seals showed clinical signs as far south as VA, although not 
in elevated numbers, therefore the UME investigation encompassed all 
seal strandings from ME to VA. The main pathogen found in the seals was 
phocine distemper virus. Information on this UME is available online 
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-unusual-mortality-events.

Gray Seal

    Gray seals in the project area belong to the western North Atlantic 
stock and range from NJ to Labrador. Current population trends show 
that gray seal abundance is likely increasing in the U.S. Atlantic EEZ 
(Hayes et al., 2022). Although the rate of increase is unknown, surveys 
conducted since their arrival in the 1980s indicate a steady increase 
in abundance in both ME and MA (Hayes et al., 2022). It is believed 
that recolonization by Canadian gray seals is the source of the U.S. 
population (Wood et al., 2011). The closest known haulout sites for 
gray seals in the vicinity of the project area are located 2.9 km (1.8 
mi) southwest (Sandy Hook Beach) outside of the ensonified area 
(Reynolds 2022). Additional haulout sites are likely Little Gull Island 
in the Long Island Sound (CRESLI, 2023). Gray seals also haul out on 
Great Gull Island and Little Gull Island in eastern Long Island Sound 
(DiGiovanni et al., 2015).
    Between July 2018 and March 2020, elevated numbers of harbor seal 
and gray seal mortalities occurred across ME, NH and MA. This event was 
declared a UME though it is currently non-active with closure pending. 
Stranded seals showed clinical signs as far south as VA, although not 
in elevated numbers, therefore the UME investigation encompassed all 
seal strandings from ME to VA. The main pathogen found in the seals was 
phocine distemper virus. Information on this UME is available online 
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-unusual-mortality-events.

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. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al., 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al., (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in table 3.

                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).

[[Page 84796]]

 
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    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 et al., 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take of Marine Mammals 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 of Marine Mammals 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 whether those impacts are reasonably expected to, or reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival.
    Acoustic effects on marine mammals during the specified activity 
can occur from impact and vibratory pile driving. These effects may 
result in Level A or Level B harassment of marine mammals in the 
project area.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far (American National Standards Institute (ANSI) 
1995). The sound level of an area is defined by the total acoustical 
energy being generated by known and unknown sources. These sources may 
include physical (e.g., waves, wind, precipitation, earthquakes, ice, 
atmospheric sound), biological (e.g., sounds produced by marine 
mammals, fish, and invertebrates), and anthropogenic sound (e.g., 
vessels, dredging, aircraft, construction).
    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 and vibratory pile driving. The sounds produced by these 
activities fall into one of two general sound types: impulsive and non-
impulsive. Impulsive sounds (e.g., explosions, gunshots, sonic booms, 
impact pile driving) are typically transient, brief (less than 1 
second), broadband, and consist of high peak sound pressure with rapid 
rise time and rapid decay [ANSI 1986; National Institute of 
Occupational Safety and Health (NIOSH) 1998; NMFS 2018]. Non-impulsive 
sounds (e.g., aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, and active sonar systems) can be 
broadband, narrowband or tonal, brief or prolonged (continuous or 
intermittent), and typically do not have the high peak sound pressure 
with rapid rise/decay time that impulsive sounds do (ANSI 1995; NIOSH 
1998; NMFS 2018). The distinction between these two sound types is 
important because they have differing potential to cause physical 
effects, particularly with regard to hearing (e.g., Ward 1997 in 
Southall et al., 2007).
    Two types of hammers would be used on this project: impact and 
vibratory. 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 
sound pressure levels (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; Carlson et al., 2005).
    The likely or possible impacts of Transco's proposed activity on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of equipment and personnel; however, any impacts to marine 
mammals are expected to be primarily acoustic in nature.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving is the means by which marine mammals may 
be harassed from Transco's specified activity. In general, animals 
exposed to natural or anthropogenic sound may experience behavioral, 
physiological, and/or physical effects, ranging in magnitude from none 
to severe (Southall et al., 2007, 2019). In general, exposure to pile 
driving noise has the potential to result

[[Page 84797]]

in behavioral reactions (e.g., avoidance, temporary cessation of 
foraging and vocalizing, changes in dive behavior) and, in limited 
cases, auditory threshold shifts. Exposure to anthropogenic noise can 
also lead to non-observable physiological responses such an increase in 
stress hormones. Additional noise in a marine mammal's habitat can mask 
acoustic cues used by marine mammals to carry out daily functions such 
as communication and predator and prey detection. The effects of pile 
driving noise on marine mammals are dependent on several factors, 
including, but not limited to, sound type (e.g., impulsive vs. non-
impulsive), the species, age and sex class (e.g., adult male vs. mom 
with calf), duration of exposure, the distance between the pile and the 
animal, received levels, behavior at time of exposure, and previous 
history with exposure (Wartzok et al., 2004; Southall et al., 2007). 
Here we discuss physical auditory effects (threshold shifts) followed 
by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS 2018). Available data from 
humans and other terrestrial mammals indicate that a 40 dB threshold 
shift approximates PTS onset (see Ward et al., 1958, 1959; Ward 1960; 
Kryter et al., 1966; Miller 1974; Ahroon et al., 1996; Henderson et 
al., 2008). PTS levels for marine mammals are estimates, as with the 
exception of a single study unintentionally inducing PTS in a harbor 
seal (Kastak et al., 2008), there are no empirical data measuring PTS 
in marine mammals largely due to the fact that, for various ethical 
reasons, experiments involving anthropogenic noise exposure at levels 
inducing PTS are not typically pursued or authorized (NMFS 2018).
    Temporary Threshold Shift (TTS)--A temporary, reversible increase 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS 2018). Based on data from cetacean TTS measurements (see 
Southall et al., 2007), a TTS of 6 dB is considered the minimum 
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et 
al., 2000; Finneran et al., 2000, 2002). As described in Finneran 
(2015), marine mammal studies have shown the amount of TTS increases 
with cumulative sound exposure level (SELcum) in an accelerating 
fashion: At low exposures with lower SELcum, the amount of TTS is 
typically small and the growth curves have shallow slopes. At exposures 
with higher SELcum, the growth curves become steeper and approach 
linear relationships with the noise SEL.
    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 (similar to those discussed in Masking, 
below). For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that takes place during a time when the animal is traveling 
through the open ocean, where ambient noise is lower and there are not 
as many competing sounds present. Alternatively, a larger amount and 
longer duration of TTS sustained during time when communication is 
critical for successful mother/calf interactions could have more 
serious impacts. We note that reduced hearing sensitivity as a simple 
function of aging has been observed in marine mammals, as well as 
humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor 
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis)) 
and five species of pinnipeds exposed to a limited number of sound 
sources (i.e., mostly tones and octave-band noise) in laboratory 
settings (Finneran 2015). TTS was not observed in trained spotted 
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive 
noise at levels matching previous predictions of TTS onset (Reichmuth 
et al., 2016). In general, harbor seals and harbor porpoises have a 
lower TTS onset than other measured pinniped or cetacean species 
(Finneran 2015). Additionally, the existing marine mammal TTS data come 
from a limited number of individuals within these species. No data are 
available on noise-induced hearing loss for mysticetes. For summaries 
of data on TTS in marine mammals or for further discussion of TTS onset 
thresholds, please see Southall et al., (2007), Finneran and Jenkins 
(2012), Finneran (2015), and table 5 in NMFS (2018).
    Activities for this project include impact and vibratory pile 
driving. There would likely be pauses in activities producing the sound 
during each day. Given these pauses and the fact that many marine 
mammals are likely moving through the project areas and not remaining 
for extended periods of time, the potential for threshold shift 
declines.
    Behavioral Harassment--Exposure to noise from pile driving also has 
the potential to behaviorally disturb marine mammals. Available studies 
show wide variation in response to underwater sound; therefore, it is 
difficult to predict specifically how any given sound in a particular 
instance might affect marine mammals perceiving the signal. If a marine 
mammal does react briefly to an underwater sound by changing its 
behavior or moving a small distance, the impacts of the change are 
unlikely to be significant to the individual, let alone the stock or 
population. However, if a sound source displaces marine mammals from an 
important feeding or breeding area for a prolonged period, impacts on 
individuals and populations could be significant (e.g., Lusseau and 
Bejder 2007; Weilgart 2007; National Research Council (NRC) 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or

[[Page 84798]]

aggressive behavior (such as tail/fluke slapping or jaw clapping); 
avoidance of areas where sound sources are located. Pinnipeds may 
increase their haul out time, possibly to avoid in-water disturbance 
(Thorson and Reyff 2006). 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., 2004; 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). In 
general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. Please see Appendices B and C of Southall et 
al., (2007) for a review of studies involving marine mammal behavioral 
responses to sound.
    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; 
Melc[oacute]n et al., 2012). In addition, behavioral state of the 
animal plays a role in the type and severity of a behavioral response, 
such as disruption to foraging (e.g., Sivle et al., 2016). 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 (Goldbogen et al., 2013).
    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), however 
distress is an unlikely result of this project based on observations of 
marine mammals during previous, similar projects in the area.
    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., pile driving, 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. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked.
    Airborne Acoustic Effects--Airborne noise would 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 their heads above water. Most likely, airborne sound would cause 
behavioral responses similar to

[[Page 84799]]

those discussed above in relation to underwater sound. For instance, 
anthropogenic sound could cause hauled-out pinnipeds to exhibit changes 
in their normal behavior, such as reduction in vocalizations, or cause 
them to temporarily abandon the area and move further from the source. 
However, these animals would previously have been ``taken'' because 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. Therefore, 
we do not believe that authorization of incidental take resulting from 
airborne sound for pinnipeds is warranted, and airborne sound is not 
discussed further. Cetaceans are not expected to be exposed to airborne 
sounds that would result in harassment as defined under the MMPA.

Marine Mammal Habitat Effects

    The proposed activities would not result in permanent impacts to 
habitats used directly by marine mammals, but may have potential short-
term impacts to food sources such as forage fish. The proposed 
activities could also affect acoustic habitat (see masking discussion 
above), but meaningful impacts are unlikely. There are no known 
foraging hotspots, or other ocean bottom structures of significant 
biological importance to marine mammals present in the project area. 
Therefore, the main impact issue associated with the proposed activity 
would be temporarily elevated sound levels and the associated direct 
effects on marine mammals, as discussed previously. The most likely 
impact to marine mammal habitat occurs from pile driving effects on 
likely marine mammal prey (e.g., fish). Impacts to the immediate 
substrate during installation of piles are anticipated, but these would 
be limited to minor, temporary suspension of sediments, which could 
impact water quality and visibility for a short amount of time, without 
any expected effects on individual marine mammals. Impacts to substrate 
are therefore not discussed further.
    In-water Construction Effects on Potential Prey--Sound may affect 
marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton). Marine mammal prey varies by species, season, and 
location and, for some, is not well documented. Here, we describe 
studies regarding the effects of noise on known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fishes hear sounds using pressure and 
particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
Hastings and Popper (2005) identified several studies that suggest fish 
may relocate to avoid certain areas of sound energy. Additional studies 
have documented effects of pile driving on fish, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). Several studies have demonstrated that impulse sounds might 
affect the distribution and behavior of some fishes, potentially 
impacting foraging opportunities or increasing energetic costs (e.g., 
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 
1992; Santulli et al., 1999; Paxton et al., 2017). However, some 
studies have shown no or slight reaction to impulse sounds (e.g., Pena 
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott 
et al., 2012). More commonly, though, the impacts of noise on fish are 
temporary.
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al., (2012a) showed that a TTS of 4-6 dB was recoverable within 24 
hours for one species. Impacts would be most severe when the individual 
fish is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    The most likely impact to fish from pile driving activities in the 
project area would be temporary behavioral avoidance of the area. The 
duration of fish avoidance of an area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. In general, impacts to marine mammal prey 
species are expected to be minor and temporary due to the expected 
short daily duration of individual pile driving events and the 
relatively small areas being affected.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through the IHA, which will inform both 
NMFS' consideration of ``small numbers,'' and the negligible impact 
determinations.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of the acoustic sources (i.e., impact and vibratory pile driving) has 
the potential to result in disruption of behavioral patterns for 
individual marine mammals. There is also some potential for auditory 
injury (Level A harassment) to result, for phocids because predicted 
auditory injury zones are relatively large, and seals are expected to 
be relatively common and are more difficult to detect at greater 
distances. The proposed mitigation and monitoring measures are expected 
to minimize the severity of the taking to the extent practicable.
    As described previously, no serious injury or mortality is 
anticipated or

[[Page 84800]]

proposed to be authorized for this activity. Below we describe how the 
proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the proposed take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile 
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by TTS as, in most cases, the likelihood of 
TTS occurs at distances from the source less than those at which 
behavioral harassment is likely. TTS of a sufficient degree can 
manifest as behavioral harassment, as reduced hearing sensitivity and 
the potential reduced opportunities to detect important signals 
(conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur.
    Transco's proposed activity includes the use of continuous 
(vibratory pile driving) and impulsive (impact pile driving) sources, 
and therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa is/
are applicable.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). Transco's 
proposed activity includes the use of impulsive (impact pile driving) 
and non-impulsive (vibratory pile driving) sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [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.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., pile driving).

[[Page 84801]]

    The project includes vibratory and impact pile driving. Source 
levels for these activities are based on reviews of measurements of the 
same or similar types and dimensions of piles available in the 
literature. Source levels for each pile size and activity are presented 
in table 5. Source levels for vibratory installation and removal of 
piles of the same diameter are assumed to be the same.

Table 5--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Installation of 36-
                                              Inch Steel Sheet Pile
----------------------------------------------------------------------------------------------------------------
           Hammer type                   dB rms             dB SEL            dB peak         Literature source
----------------------------------------------------------------------------------------------------------------
Vibratory........................                182                N/A                N/A  Quijano et al.,
                                                                                             2018.
Impact...........................                190                180                205  Caltrans, 2015.
----------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.

    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

    TL = B * Log10 (R1/R2), where

TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement

    Absent site-specific acoustical monitoring with differing measured 
transmission loss, a practical spreading value of 15 is used as the 
transmission loss coefficient in the above formula. Site-specific 
transmission loss data for the Raritan Bay is not available; therefore, 
the default coefficient of 15 is used to determine the distances to the 
harassment thresholds.
    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the Technical Guidance that can be used 
to relatively simply predict an isopleth distance for use in 
conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources such as pile driving, the optional User Spreadsheet 
tool predicts the distance at which, if a marine mammal remained at 
that distance for the duration of the activity, it would be expected to 
incur PTS. Inputs used in the optional User Spreadsheet tool, and the 
resulting estimated isopleths, are reported below (table 6). The 
resulting estimated isopleths and the calculated Level B harassment 
isopleths are reported in table 7.

                    Table 6--User Spreadsheet Inputs
------------------------------------------------------------------------
                        36-inch steel sheet piles
-------------------------------------------------------------------------
                                     (A.1) Vibratory   (E.1) Impact pile
       Spreadsheet tab used            pile driving         driving
------------------------------------------------------------------------
Source Level (SPL)................            182 RMS            180 SEL
Transmission Loss Coefficient.....                 15                 15
Weighting Factor Adjustment (kHz).                2.5                  2
Activity Duration per pile                         10                N/A
 (minutes)........................
Number of strikes per pile........  .................                520
Number of piles per day...........                 12                 12
Distance of sound pressure level                    1                 10
 measurement......................
------------------------------------------------------------------------


                                              Table 7--Level A Harassment and Level B Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Level A harassment isopleths (m) [bond] area of harassment zone (km\2\) *       Level B
                                                          ----------------------------------------------------------------------------     harassment
                                                                                                                                          isopleth (m)
                       Hammer type                                                                                                       [bond] area of
                                                                   LF                 MF                 HF                 PW          harassment zone
                                                                                                                                           (km\2\) *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                36-Inch Steel Sheet Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving...................................               27.2                2.4               40.3               16.6      13,594 [bond]
                                                                                                                                                  426.13
Impact Pile Driving......................................     2,135.6 [bond]   76.0 [bond] 0.30     2,543.9 [bond]     1,142.9 [bond]              1,000
                                                                       18.99                                 25.23               7.72
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Harassment zone areas are clipped by viewshed.


[[Page 84802]]

Marine Mammal Occurrence

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations.
    Transco applied the Duke University Marine Geospatial Ecology 
Laboratory marine mammal habitat-based density models (https://seamap.env.duke.edu/models/Duke/EC/) to estimate take from vibratory 
and impact pile driving (Roberts et al., 2016; Roberts et al., 2023). 
These density data incorporate aerial and shipboard line-transect data 
from NMFS and other organizations and incorporate data from 8 
physiographic and 16 dynamic oceanographic and biological covariates, 
and control for the influence of sea state, group size, availability 
bias, and perception bias on the probability of making a sighting. 
These density models were originally developed for all cetacean taxa in 
the U.S. Atlantic (Roberts et al., 2016). Most recently, all models 
were updated in 2022 based on additional data as well as certain 
methodological improvements. More information is available online at 
https://seamap.env.duke.edu/models/Duke/EC/. Marine mammal density 
estimates in the project area (animals/km\2\) were obtained using the 
most recent model results for all taxa (Roberts et al., 2023).
    For each species, the average monthly density (June-September) near 
work area 3, Sandy Hook Channel, was calculated (table 8). 
Specifically, in a Geographic Information Systems, density rasters were 
clipped to polygons representing the zone of influence for Level A 
harassment zones for each hearing group and the largest Level B 
harassment zone, which applies to all hearing groups. Densities in 
Roberts et al., (2023) are provided in individuals per 100 square km, 
however they were converted to individuals per square km for ease of 
calculation. The monthly maximum density of individuals per square km 
for each zone of influence was averaged over the months of June to 
September near work area 3 to provide a single density estimate for 
each species or species group. The available density information 
provides densities for seals as a guild due to difficulty in 
distinguishing these species at sea. Similarly, density information for 
bottlenose dolphins does not differentiate between stocks. The 
resulting density values (table 8) were used to calculate take 
estimates of marine mammals for sheet pile installation activities. 
Note that other data sources were evaluated for pinnipeds (e.g., Save 
Coastal Wildlife reports) but were found unsuitable due to data quality 
and applicability.

                         Table 8--Average Monthly Density of Species in the Project Area
                                                [June-September]
----------------------------------------------------------------------------------------------------------------
                                                                Average monthly density  Average monthly density
                                                                  (individual/ km\2\)      (individual/ km\2\)
                                                                  used in Level B take     used in Level A take
                            Species                               calculations at work     calculations at work
                                                                   area 3, Sandy Hook       area 3, Sandy Hook
                                                                     channel (June-           channel (June-
-----------------------------------------------------------------------September)---------------September)------
Fin Whale.....................................................              1.41361E-04              4.53952E-06
Humpback Whale................................................              9.37889E-05              2.14387E-05
Minke Whale...................................................              2.34113E-04              3.12779E-05
Atlantic white-sided dolphin..................................              4.97340E-05              6.98975E-07
Bottlenose dolphin............................................              1.88295E-01              4.76450E-02
Harbor porpoise...............................................              1.64816E-04              3.27277E-05
Common dolphin................................................              5.91282E-04              1.24663E-05
Atlantic Spotted Dolphin......................................              2.38665E-04              8.76649E-07
Harp Seals, Gray Seals, Harbor Seals..........................                  0.11387                  0.11130
----------------------------------------------------------------------------------------------------------------

Take Estimation

    Here we describe how the information provided above is synthesized 
to produce a quantitative estimate of the take that is reasonably 
likely to occur and proposed for authorization.
    Take estimates are the product of density, ensonified area, and 
number of days of pile driving work. Specifically, take estimates are 
calculated by multiplying the expected densities of marine mammals in 
the activity area(s) by the area of water likely to be ensonified above 
the NMFS defined threshold levels in a single day (24-hour period). 
Transco used the construction method that produced the largest isopleth 
to estimate exposure of marine mammal noise impacts (i.e., the largest 
ensonified area estimated for vibratory pile driving was used to 
estimate potential takes by Level B harassment, and the hearing group-
specific ensonified areas estimated for impact pile driving were used 
to estimate potential Level A harassment). Next, that product is 
multiplied by the number of days vibratory or impact pile driving is 
likely to occur. The exposure estimate was rounded to the nearest whole 
number at the end of the calculation. A summary of this method is 
illustrated in the following formula:

Estimated Take = D x ZOI x # of construction days

Where:

D = density estimate for each species within the ZOI
ZOI = maximum daily ensonified area (km\2\) to relevant thresholds

    For bottlenose dolphins, the density data presented by Roberts et 
al., (2023) does not differentiate between bottlenose dolphin stocks. 
Thus, the take estimate for bottlenose dolphins calculated by the 
method described above resulted in an estimate of the total number of 
bottlenose dolphins expected to be taken, from all stocks (for a total 
of 6,419 takes by Level B harassment). However, as described above, 
both the Western North Atlantic Northern Migratory Coastal stock and 
the Western North Atlantic Offshore stock have the potential to occur 
in the project area. Because approximately 95% of the project area 
occurs in waters shallower than 20 m, we assign take to stock 
accordingly. Thus, we assume that 95 percent of the total proposed 
authorized bottlenose dolphin takes would accrue to the Western North 
Atlantic Offshore stock (total 6,098 takes by Level B harassment), and 
5 percent to the Western North Atlantic Northern Migratory Coastal 
stock (total 321 takes by Level B harassment) (table 9).
    Additional data regarding average group sizes from survey effort in 
the

[[Page 84803]]

region was considered to ensure adequate take estimates are evaluated. 
Take estimates for several species were adjusted based upon average 
groups sizes derived from NOAA Atlantic Marine Assessment Program for 
Protected Species data from 2010-2019 shipboard distance sampling 
surveys (Palka et al., 2021). This is particularly true for uncommon or 
rare species with very low densities in the models. These calculated 
take estimates were adjusted for these species as follows:
     Atlantic white-sided dolphin: Only 1 take by Level B 
harassment was estimated but takes proposed for authorization were 
increased to the average number of dolphins in a group reported in 
Palka et al., 2021 (n = 12);
     Common dolphin: Only 26 takes were estimated but takes 
proposed for authorization were increased to the average number of 
dolphins in a group reported in Palka et al., 2021 (n = 30);
     Atlantic spotted dolphin: Only 9 takes were estimated but 
takes proposed for authorization were increased to the average number 
of dolphins in a group reported in Palka et al., 2021 (n = 24);

           Table 9--Proposed Take by Stock and Harassment Type and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
                                                                     Proposed authorized take      Proposed take
                                                                 --------------------------------      as a
                Species                           Stock                                            percentage of
                                                                      Level B         Level A          stock
                                                                    harassment      harassment      abundance *
----------------------------------------------------------------------------------------------------------------
Fin Whale.............................  Western North Atlantic..               5               0              <1
Humpback Whale........................  Gulf of Maine...........               3               0              <1
Minke Whale...........................  Canadian East Coast.....               8               0              <1
Atlantic White-sided Dolphin..........  Western North Atlantic..              12               0              <1
Bottlenose Dolphin....................  Northern Migratory                 6,098               0              92
                                         Coastal.
                                        Western North Atlantic               321               0              <1
                                         Offshore.
Harbor Porpoise.......................  Gulf of Maine/Bay of                   6               0              <1
                                         Fundy.
Common Dolphin........................  Western North Atlantic..              30               0              <1
Atlantic Spotted Dolphin..............  Western North Atlantic..              24               0              <1
Harbor Seal...........................  Western North Atlantic..           3,813              69             6.3
Gray Seal.............................  Western North Atlantic..                                              <1
Harp Seal.............................  Western North Atlantic..                                              <1
----------------------------------------------------------------------------------------------------------------

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 the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the 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 the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers 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, and impact on 
operations.
    Transco has indicated that pile driving will be conducted between 
June 15 and September 15, a time of year when North Atlantic Right 
Whales are unlikely to occur near the project area. NMFS proposes the 
following mitigation measures be implemented for Transco's pile 
installation activities.
    Shutdown Zones--For all pile driving activities, Transco would 
implement shutdowns within designated zones. The purpose of a shutdown 
zone is generally to define an area within which shutdown of the 
activity would occur upon sighting of a marine mammal (or in 
anticipation of an animal entering the defined area). Shutdown zones 
vary based on the activity type and marine mammal hearing group (table 
10). In most cases, the shutdown zones are based on the estimated Level 
A harassment isopleth distances for each hearing group. However, in 
cases where it would be challenging to detect marine mammals at the 
Level A harassment isopleth and frequent shutdowns would create 
practicability concerns (e.g., for phocids during impact pile driving), 
smaller shutdown zones have been proposed (table 10). Additionally, 
Transco has agreed to implement a minimum shutdown zone of 60 m during 
all pile driving activities.
    Finally, construction supervisors and crews, Protected Species 
Observers (PSOs), and relevant Transco staff must avoid direct physical 
interaction with marine mammals during construction activity. If a 
marine mammal comes within 10 m of such activity, operations must cease 
and vessels must reduce speed to the minimum level required to maintain 
steerage and safe working conditions, as necessary to avoid direct 
physical interaction. If an activity is delayed or halted due to the 
presence of a marine mammal, the activity may not commence or resume 
until either the animal has voluntarily exited and been visually 
confirmed beyond the shutdown zone indicated in table 10 or 15 minutes 
have passed without re-detection of the animal.
    Construction activities must be halted upon observation of a 
species for which incidental take is not authorized or a species for 
which incidental take has been authorized but the authorized number of 
takes has been met entering or within the harassment zone. In the case 
of North Atlantic right whale,

[[Page 84804]]

construction activities must be halted upon observation of this species 
at any distance, regardless of its proximity to a harassment zone.

                                                            Table 10--Proposed Shutdown Zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                    Shutdown zones (m)
                                                                ----------------------------------------------------------------------------------------
               Activity                        Pile type           North Atlantic right
                                                                          whale            Low frequency   Mid frequency  High frequency      Phocid
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation...............  36-inch sheet...........  Any distance...........                                60
                                                                                         ---------------------------------------------------------------
Impact Installation..................                                                              1,000              80             200             150
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Protected Species Observers (PSOs)--The number and placement of 
PSOs during all construction activities (described in the Proposed 
Monitoring and Reporting section) would ensure that the entire shutdown 
zone is visible. Transco would employ at least two PSOs for all pile 
driving activities.
    Monitoring for Level A and Level B Harassment--PSOs would monitor 
the shutdown zones and beyond to the extent that PSOs can see. 
Monitoring beyond the shutdown zones enables observers to be aware of 
and communicate the presence of marine mammals in the project areas 
outside the shutdown zones and thus prepare for a potential cessation 
of activity should the animal enter the shutdown zone. If a marine 
mammal enters either harassment zone, PSOs will document the marine 
mammal's presence and behavior.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving of 30 
minutes or longer occurs, PSOs will observe the shutdown, Level A 
harassment, and Level B harassment zones for a period of 30 minutes. 
Pre-start clearance monitoring must be conducted during periods of 
visibility sufficient for the lead PSO to determine that the shutdown 
zones are clear of marine mammals. If the shutdown zone is obscured by 
fog or poor lighting conditions, in-water construction activity will 
not be initiated until the entire shutdown zone is visible. Pile 
driving may commence following 30 minutes of observation when the 
determination is made that the shutdown zones are clear of marine 
mammals. If a marine mammal is observed entering or within shutdown 
zones, pile driving activity must be delayed or halted. If pile driving 
is delayed or halted due to the presence of a marine mammal, the 
activity may not commence or resume until either the animal has 
voluntarily exited and been visually confirmed beyond the shutdown zone 
or 15 minutes have passed without re-detection of the animal. If a 
marine mammal for which Level B harassment take is authorized is 
present in the Level B harassment zone, activities may begin.
    Soft-Start--The use of soft-start procedures are believed to 
provide additional protection to marine mammals by providing warning 
and/or giving marine mammals a chance to leave the area prior to the 
hammer operating at full capacity. For impact pile driving, contractors 
would be required to provide an initial set of three strikes from the 
hammer at reduced energy, with each strike followed by a 30-second 
waiting period. This procedure would be conducted a total of three 
times before impact pile driving begins. Soft start would 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 30 
minutes or longer. Soft start is not required during vibratory pile 
driving activities.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on 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 while 
conducting the activities. 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 activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.
    Visual Monitoring--Marine mammal monitoring during pile driving 
activities must be conducted by NMFS-approved PSOs in a manner 
consistent with the following:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor), and have no other assigned tasks 
during monitoring periods;
     At least one PSO must have prior experience performing the 
duties of a PSO during construction activity

[[Page 84805]]

pursuant to a NMFS-issued incidental take authorization;
     Other PSOs may substitute other relevant experience, 
education (degree in biological science or related field) or training 
for experience performing the duties of a PSO during construction 
activities pursuant to a NMFS-issued incidental take authorization.
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator will be designated. The lead 
observer will be required to have prior experience working as a marine 
mammal observer during construction activity pursuant to a NMFS-issued 
incidental take authorization; and,
     PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA.
    PSOs should also have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     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 note implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Visual monitoring will be conducted by a minimum of two trained 
PSOs positioned at suitable vantage points on or near the maintenance 
barge. One PSO will have an unobstructed view of all water within the 
shutdown zone. Remaining PSOs will observe as much as the Level A and 
Level B harassment zones as possible.
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after all in water construction activities. In addition, PSOs 
will record all incidents of marine mammal occurrence, regardless of 
distance from activity, and will document any behavioral reactions in 
concert with distance from piles being driven or removed. 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 30 minutes.

Reporting

    Transco will submit a draft marine mammal monitoring report to NMFS 
within 90 days after the completion of pile driving activities, or 60 
days prior to a requested date of issuance of any future IHAs for the 
project, or other projects at the same location, whichever comes first. 
The marine mammal monitoring report will include an overall description 
of work completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report will include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including: (1) The number and type of piles that 
were driven and the method (e.g., impact or vibratory); and, (2) Total 
duration of driving time for each pile (vibratory driving) and number 
of strikes for each pile (impact driving);
     PSO locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information: (1) Name of PSO who sighted the animal(s) and PSO location 
and activity at time of sighting; (2) Time of sighting; (3) 
Identification of the animal(s) (e.g., genus/species, lowest possible 
taxonomic level, or unidentified), PSO confidence in identification, 
and the composition of the group if there is a mix of species; (4) 
Distance and location of each observed marine mammal relative to the 
pile being driven for each sighting; (5) Estimated number of animals 
(min/max/best estimate); (6) Estimated number of animals by cohort 
(adults, juveniles, neonates, group composition, etc.); (7) Animal's 
closest point of approach and estimated time spent within the 
harassment zone; (8) Description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
     Number of marine mammals detected within the harassment 
zones, by species; and,
     Detailed information about implementation of any 
mitigation (e.g., shutdowns and delays), a description of specific 
actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    A final report must be prepared and submitted within 30 calendar 
days following receipt of any NMFS comments on the draft report. If no 
comments are received from NMFS within 30 calendar days of receipt of 
the draft report, the report shall be considered final. All PSO data 
would be submitted electronically in a format that can be queried such 
as a spreadsheet or database and would be submitted with the draft 
marine mammal report.
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the Holder must report the 
incident to the Office of Protected Resources (OPR), NMFS 
([email protected] and [email protected]) and 
Greater Atlantic Region New England/Mid-Atlantic Regional Stranding 
Coordinator (978-282-8478 or 978-281-9291) as soon as feasible. If the 
death or injury was clearly caused by the specified activity, the 
Holder must immediately cease the activities until NMFS OPR is able to 
review the circumstances of the incident and determine what, if any, 
additional measures are appropriate to ensure compliance with the terms 
of this IHA. The Holder must not resume their activities until notified 
by NMFS. The report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival

[[Page 84806]]

(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 impacts or 
responses (e.g., intensity, duration), the context of any impacts or 
responses (e.g., critical reproductive time or location, foraging 
impacts affecting energetics), 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' 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 baseline 
(e.g., as reflected in the regulatory status of the species, population 
size and growth rate where known, ongoing sources of human-caused 
mortality, or ambient noise levels).
    To avoid repetition, the majority of our analysis applies to all 
the species listed in table 2, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, they are described independently in the analysis below.
    Pile driving associated with the Transco LNYBL maintenance project, 
as outlined previously, has the potential to disturb or displace marine 
mammals. Specifically, the specified activities may result in take, in 
the form of Level B harassment and, for some species, Level A 
harassment, from underwater sounds generated by pile driving.
    No serious injury or mortality would be expected, even in the 
absence of required mitigation measures, given the nature of the 
activities. Further, no take by Level A harassment is anticipated for 
low-frequency, mid-frequency, or high-frequency cetaceans. The 
potential for harassment would be minimized through the implementation 
of planned mitigation measures (see Proposed Mitigation section).
    Take by Level A harassment is expected for pinnipeds (harbor seal, 
harp seal, and gray seal). Any take by Level A harassment is expected 
to arise from, at most, a small degree of PTS (i.e., minor degradation 
of hearing capabilities within regions of hearing that align most 
completely with the energy produced by impact pile driving such as the 
low-frequency region below 2 kHz), not severe hearing impairment or 
impairment within the ranges of greatest hearing sensitivity. Animals 
would need to be exposed to higher levels and/or longer duration than 
are expected to occur here in order to incur any more than a small 
degree of PTS.
    Further, the amount of take proposed for authorization by Level A 
harassment is very low for all marine mammal stocks and species. For 
eight species, NMFS anticipates no Level A harassment take over the 
duration of Transco's planned activities; for pinnipeds, NMFS expects 
no more than 69 takes by Level A harassment across all 3 pinniped 
species (harbor seal, gray seal, harp seal). If hearing impairment 
occurs, it is most likely that the affected animal would lose only a 
few decibels in its hearing sensitivity. Due to the small degree 
anticipated, any PTS potential incurred would not be expected to affect 
the reproductive success or survival of any individuals, much less 
result in adverse impacts on the species or stock.
    Additionally, some subset of the individuals that are behaviorally 
harassed could also simultaneously incur some small degree of TTS for a 
short duration of time. However, since the hearing sensitivity of 
individuals that incur TTS is expected to recover completely within 
minutes to hours, it is unlikely that the brief hearing impairment 
would affect the individual's long-term ability to forage and 
communicate with conspecifics, and would therefore not likely impact 
reproduction or survival of any individual marine mammal, let alone 
adversely affect rates of recruitment or survival of the species or 
stock.
    As described above, NMFS expects that marine mammals would likely 
move away from an aversive stimulus, especially at levels that would be 
expected to result in PTS, given sufficient notice through use of soft 
start. Transco would also shut down pile driving activities if marine 
mammals enter the shutdown zones (table 10) further minimizing the 
degree of PTS that would be incurred.
    Effects on individuals that are taken by Level B harassment in the 
form of behavioral disruption, on the basis of reports in the 
literature as well as monitoring from other similar activities, would 
likely be limited to reactions such as avoidance, increased swimming 
speeds, increased surfacing time, or decreased foraging (if such 
activity were occurring) (e.g., Thorson and Reyff, 2006). Most likely, 
individuals would simply move away from the sound source and 
temporarily avoid the area where pile driving is occurring. If sound 
produced by project activities is sufficiently disturbing, animals are 
likely to simply avoid the area while the activities are occurring. We 
expect that any avoidance of the project areas by marine mammals would 
be temporary in nature and that any marine mammals that avoid the 
project areas during construction would not be permanently displaced. 
Short-term avoidance of the project areas and energetic impacts of 
interrupted foraging or other important behaviors is unlikely to affect 
the reproduction or survival of individual marine mammals, and the 
effects of behavioral disturbance on individuals is not likely to 
accrue in a manner that would affect the rates of recruitment or 
survival of any affected stock.
    As described above, humpback whales, and gray, harbor and harp 
seals are experiencing ongoing UMEs. With regard to humpback whales, 
the UME does not yet provide cause for concern regarding population-
level impacts. Despite the UME, the relevant population of humpback 
whales (the West Indies breeding population, or DPS) remains healthy. 
The West Indies DPS, which consists of the whales whose breeding range 
includes the Atlantic margin of the Antilles from Cuba to northern 
Venezuela, and whose feeding range primarily includes the Gulf of 
Maine, eastern Canada, and western Greenland, was delisted. The status 
review identified harmful algal blooms, vessel collisions, and fishing 
gear entanglements as relevant threats for this DPS, but noted that all 
other threats are considered likely to have no or minor impact on 
population size or the growth rate of this DPS (Bettridge et al., 
2015). As described in Bettridge et al., (2015), the West Indies DPS 
has a substantial population size (i.e., approximately 10,000; Stevick 
et al., 2003; Smith et al., 1999; Bettridge et al., 2015), and appears 
to be experiencing consistent growth.
    In regards to pinnipeds (harbor seals, gray seals and harp seals), 
we do not expect takes that may be authorized under this IHA to 
exacerbate or compound upon ongoing UMEs. Between July 2018 and March 
2020, elevated seal mortalities occurred across ME, NH and MA, and as 
far south as VA due to phocine distemper virus (the

[[Page 84807]]

UME is still active but pending closure). Since June 2022, a UME has 
been declared for Northeast pinnipeds in which elevated numbers of sick 
and dead harbor seals, gray seals, and harp seals have been documented 
along the southern and central coast of ME (NOAA Fisheries, 2022). 
Between June 1, 2022 and July 16, 2023, 65 grays seals, 379 harbor 
seals, and 6 harp seals have stranded. As noted previously, no injury, 
serious injury, or mortality is expected or will be authorized, and 
takes of harbor seal, gray seal, and harp seal will be minimized 
through the incorporation of the required mitigation measures. The 
population abundance for these species is 61,336, 27,300, and 7.6 
million, respectively (Hayes et al., 2022). The 3,882 takes that may be 
authorized across these species represent a small proportion of each 
population and as such we do not expect this authorization to 
exacerbate or compound upon these UMEs.
    The project is also not expected to have significant adverse 
effects on affected marine mammals' habitats. No ESA-designated 
critical habitat or recognized Biologically Important Areas are located 
within the project area. The project activities would not modify 
existing marine mammal habitat for a significant amount of time. The 
activities may cause a low level of turbidity in the water column and 
some fish may leave the area of disturbance, thus temporarily impacting 
marine mammals' foraging opportunities in a limited portion of the 
foraging range; but, because of the short duration of the activities 
and the relatively small area of the habitat that may be affected (with 
no known particular importance to marine mammals), the impacts to 
marine mammal habitat are not expected to cause significant or long-
term negative consequences. The closest pinniped haulout is located 2.9 
km from the work area but does not intersect with the harassment zones.
    For all species and stocks, take would occur within a limited, 
relatively confined area (primarily Raritan Bay) of the stock's range, 
which is not of particular importance for marine mammals that may occur 
there. Given the availability of suitable habitat nearby, any 
displacement of marine mammals from the project areas is not expected 
to affect marine mammals' fitness, survival, and reproduction due to 
the limited geographic area that would be affected in comparison to the 
much larger habitat for marine mammals outside the bay along the NJ and 
NY coasts. Additionally, NMFS anticipates that the prescribed 
mitigation will minimize the duration and intensity of expected 
harassment events.
    Some individual marine mammals in the project area, such as harbor 
seals or bottlenose dolphins, may be present and be subject to repeated 
exposure to sound from pile driving activities on multiple days. 
However, pile driving and extraction is not expected to occur on every 
day, and these individuals would likely return to normal behavior 
during gaps in pile driving activity within each day of construction 
and in between work days. As discussed above, individuals could 
temporarily relocate during construction activities to reduce exposure 
to elevated sound levels from the project. Additionally, haulout 
habitat available for pinnipeds does not intersect with the harassment 
zones. Therefore, any behavioral effects of repeated or long duration 
exposures are not expected to negatively affect survival or 
reproductive success of any individuals. Thus, even repeated Level B 
harassment of some small subset of an overall stock is unlikely to 
result in any effects on rates of reproduction and survival of the 
stock.
    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 any of the species 
or stocks through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or 
authorized;
     The anticipated impacts of the proposed activity on marine 
mammals would be temporary behavioral changes due to avoidance of the 
project area and limited instances of Level A harassment in the form of 
a slight PTS for pinnipeds. Potential instances of exposure above the 
Level A harassment threshold are expected to be relatively low for most 
species;
     The availability of alternate areas of similar habitat 
value nearby;
     Effects on species that serve as prey species for marine 
mammals from the proposed project are expected to be short-term and are 
not expected to result in significant or long-term consequences for 
individual marine mammals, or to contribute to adverse impacts on their 
populations;
     There are no known important feeding, breeding, or calving 
areas in the project area.
     The proposed mitigation measures, including visual 
monitoring, shutdown zones, and soft start, are expected to minimize 
potential impacts to marine mammals.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    We propose to authorize incidental take of 12 marine mammal stocks. 
The total amount of taking proposed for authorization is well below 
one-third of the estimated stock abundance for all species except for 
the western north Atlantic northern coastal migratory stock of 
bottlenose dolphins (table 9).
    The total number of authorized takes for bottlenose dolphins, if 
assumed to accrue solely to new individuals of the northern migratory 
coastal stock, is >90 percent of the total stock abundance, which is 
currently estimated as 6,639. However, these numbers represent the 
estimated incidents of take, not the number of individuals taken. That 
is, it is highly likely that a relatively small subset of these 
bottlenose dolphins will be harassed by project activities.
    Western North Atlantic Northern Migratory Coastal bottlenose 
dolphins make broadscale, seasonal migrations in coastal waters of the 
Western north Atlantic. During the warm months, when the project is 
planned, their range extends from the shoreline to the 20 m isobaths 
between Assateague, VA to Long Island, NY (Garrison et al., 2017b), an 
area spanning approximately 300 linear km of coastline. It is likely 
that the majority of the Western North Atlantic Northern Migratory 
Coastal bottlenose dolphins would not occur within waters ensonified by 
project activities.

[[Page 84808]]

    In summary, the Western North Atlantic Northern Migratory Coastal 
bottlenose dolphins are not expected to occur in a significant portion 
of the larger ZOI. Given that the specified activity will be stationary 
within an area not recognized as any special significance that would 
serve to attract or aggregate dolphins, we therefore believe that the 
estimated numbers of takes, were they to occur, likely represent 
repeated exposures of a much smaller number of bottlenose dolphins and 
that these estimated incidents of take represent small numbers of 
bottlenose dolphins.
    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 would be taken relative to the population 
size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (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 whenever we propose to authorize take for 
endangered or threatened species, in this case with the NMFS Greater 
Atlantic Regional Fisheries Office (GARFO).
    NMFS is proposing to authorize take of the fin whale, which is 
listed under the ESA. The NMFS Office of Protected Resources has 
requested initiation of section 7 consultation with GARFO for the 
issuance of this IHA. NMFS will conclude the ESA consultation prior to 
reaching a determination regarding the proposed issuance of the 
authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to Transco for conducting the LNYBL Maintenance Project in 
Sandy Hook Channel, New Jersey (NJ) between June and August 2024, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. A draft of the proposed IHA can be found 
at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

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

    Dated: November 30, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-26704 Filed 12-5-23; 8:45 am]
BILLING CODE 3510-22-P