Notice2025-18424
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Northeast Supply Enhancement Project in Raritan Bay, Lower New York Bay and the Atlantic Ocean
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 23, 2025
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
Notification is hereby given that NMFS has issued an incidental harassment authorization (IHA) to Transcontinental Gas Pipe Line Company, LLC (Transco), a subsidiary of Williams Partners L.P., to incidentally harass marine mammals during construction activities associated with the Northeast Supply Enhancement Project in Raritan Bay, Lower New York Bay, and the Atlantic Ocean.
Full Text
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<title>Federal Register, Volume 90 Issue 182 (Tuesday, September 23, 2025)</title>
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[Federal Register Volume 90, Number 182 (Tuesday, September 23, 2025)]
[Notices]
[Pages 45730-45750]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-18424]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XF146]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Northeast Supply Enhancement
Project in Raritan Bay, Lower New York Bay and the Atlantic Ocean
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization.
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SUMMARY: Notification is hereby given that NMFS has issued an
incidental harassment authorization (IHA) to Transcontinental Gas Pipe
Line Company, LLC (Transco), a subsidiary of Williams Partners L.P., to
incidentally harass marine mammals during construction activities
associated with the Northeast Supply Enhancement Project in Raritan
Bay, Lower New York Bay, and the Atlantic Ocean.
DATES: This authorization is effective for 1 year from the date of
notification by the IHA-holder, not to exceed 1 year from the date of
issuance (September 19, 2025).
ADDRESSES: 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-
[[Page 45731]]
take-authorizations-construction-activities. In case of problems
accessing these documents, please call the contact listed below.
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. Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et
seq.) directs 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 (collectively referred to as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms used above are included in the relevant sections below
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS
regulations at 50 CFR 216.103.
Summary of Request
On May 30, 2025, NMFS received a request from Transco for an IHA to
take marine mammals incidental to the Northeast Supply Enhancement
Project in Raritan Bay, Lower New York Bay and the Atlantic Ocean (in
the New York Bight). During NMFS' application review, Transco indicated
that two hammers at the same location may operate at the same time and
provided scenarios for simultaneous pile driving on July 11, 2025,
which necessitated additional analysis. Following NMFS' review of the
application and subsequent discussions between NMFS and Transco, the
application was deemed adequate and complete on July 29, 2025.
Transco's initial request was for authorization of take of 14 species
of marine mammals by Level B harassment and, for a subset of 4 of these
species, Level A harassment. Following additional analysis, NMFS
proposed to authorize take of 15 species of marine mammals by Level B
harassment and, for a subset of 7 of these species, Level A harassment
(90 FR 38104, August 7, 2025). NMFS has authorized this take as
proposed. Neither Transco nor NMFS expect serious injury or mortality
to result from this activity and, therefore, an IHA is appropriate.
NMFS previously issued an IHA to Transco for the same project (85
FR 15125, March 17, 2020) as updated in the 2025 application. No work
was conducted under the 2020 IHA. NMFS also previously issued a
separate IHA to Transco for its Lower New York Bay Lateral Maintenance
(LNYBL) that occurred in the same region (89 FR 20170, March 21, 2024).
Transco conducted all required monitoring and reporting under the 2024
IHA, and information regarding Transco's monitoring results may be
found in the Potential Effects of the Specified Activity on Marine
Mammals and their Habitat section of the proposed IHA (90 FR 38104,
August 7, 2025).
Description of the Specified Activity
Transco plans to expand its existing interstate natural gas
transmission system in Pennsylvania and New Jersey and its existing
offshore natural gas transmission system in New Jersey and New York
waters. The offshore pipeline facilities would include the installation
of the Raritan Bay Loop, which would be located primarily in Raritan
Bay, as well as parts of the Lower New York Bay and the Atlantic Ocean.
Construction of the Raritan Bay Loop pipeline would require
vibratory and impact installation and vibratory removal of 163
temporary piles, ranging in size from 10 to 60-inches (in) (0.3 to 1.5
meters (m)) in diameter, which may result in the incidental take of
marine mammals.
A detailed description of the planned construction activities is
provided in the Federal Register notice for the proposed IHA (90 FR
38104, August 7, 2025). Since that time, no changes have been made to
the planned activities. Therefore, a detailed description is not
provided here. Please refer to that Federal Register notice for the
description of the specific activity.
Comments and Responses
NMFS published a notice of its proposal to issue an IHA to Transco
in the Federal Register on August 7, 2025 (90 FR 38104). That notice
described, in detail, Transco's specified activities, the marine mammal
species that may be affected by the activities, and the anticipated
effects on marine mammals. In that notice, we requested public input on
the request for authorization described therein, our analyses, the
proposed authorization, and any other aspect of the notice of the
proposed IHA, and requested that interested persons submit relevant
information, suggestions, and comments.
During the 30-day public comment period, NMFS received a total of
five substantive comment letters. Letters were received from one state
agency (New York State Department of Environmental Conservation), three
environmental non-governmental organizations (Clean Ocean Action, New
Yorkers for Clean Power, Protect Our Coast New Jersey), and from the
``WhoPoo App'' entity. Summaries of all relevant, substantive comments
and NMFS' responses to these comments are provided below. We have not
responded to comments that failed to raise a significant point for us
to consider (e.g., comments that are out of scope of the proposed IHA;
mitigation, monitoring, or reporting measures already included in the
proposed IHA). Furthermore, if a comment received was unclear, NMFS
does not include it here as it could not determine whether it raised a
significant point for NMFS to consider. The comments are available
online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Please see the comment submissions for full details regarding the
recommendations and supporting rationale.
Comment 1: Commenters expressed concern regarding NMFS' proposed
application of a National Environmental Policy Act (NEPA) Categorical
Exclusion (CatEx). Commenters stated that use of the CatEx is
inappropriate given what one commentator characterizes as ``the
uncertainty and uniqueness of the impacts'' related to contaminants
that the commenter asserts would be released by the project or what a
different commenter describes as the ``potential for serious acoustic
disturbance to sensitive marine mammals,'' and recommended that further
NEPA analysis be conducted.
Response: In determining whether a CatEx is appropriately applied
for a given Incidental Take Authorization
[[Page 45732]]
(ITA), NMFS considers the applicant's specified activity, in this case,
in-water construction (pile driving), and the potential extent and
magnitude of the effects of NMFS' action (i.e., the authorized
``takes'' of marine mammals and prescribed mitigation, monitoring and
reporting requirements) along with the extraordinary circumstances
listed in the Companion Manual for NOAA Administrative Order 216-6A.
The evaluation of whether extraordinary circumstances (if present) have
the potential for significant environmental effects is limited to the
decision NMFS is responsible for, which is issuance of an ITA (NMFS'
action). NMFS has prepared numerous Environmental Assessments (EAs)
analyzing the environmental impacts of authorizing take of marine
mammals incidental to construction activities such as these, which
resulted in Findings of No Significant Impact. NMFS has performed the
necessary analysis and confirmed that there are no extraordinary
circumstances present that would make use of the CatEx inappropriate
for NMFS' action of issuing an ITA for the construction activities
associated with Transco's Northeast Supply Enhancement project. The
commenters do not provide adequate support for the apparent contention
that there may be extraordinary circumstances associated with NMFS'
action of issuing the IHA.
Comment 2: One commenter stated that ``significant resuspension of
[. . .] toxin-laced sediments'' would occur as a result of the project,
specifically dredging, and suggested that resulting impacts on marine
mammals were not adequately addressed by NMFS. As discussed in response
to Comment 1, the commenter additionally suggested that these potential
impacts presented extraordinary circumstances that would make NMFS'
proposed application of a CatEx inappropriate.
Response: NMFS clarifies that our proposed action--the issuance of
the IHA authorizing incidental take of marine mammals from the
specified activities (i.e., pile driving)--analyzed the impacts of the
specified activities on marine mammals, including impacts to habitat
and potential prey species. Transco did not request and NMFS is not
authorizing incidental take of marine mammals from Transco's dredging
activities. As we discussed in the proposed Federal Register notice (90
FR 38104, August 7, 2025), there is no information suggesting more than
temporary, localized impacts to water quality and temporary impacts to
marine mammal prey from pile driving activities and, in fact, the
commenter refers to what it states are expected impacts as ``temporary
loss of habitat and foraging areas.''
The project area has not been identified as particularly important
foraging habitat for marine mammals, except for humpback whales, which
may use it as supplementary feeding habitat. In addition, Estabrook et
al. (2025) noted that humpback whale calls were more frequently
detected near New York Harbor between November and March, and at sites
near the shelf edge, away from the project area, between July and
September when most of the project activities are planned. NMFS' review
of the available information does not indicate that the expected
temporary effects could be significant enough to impact marine mammal
prey to the extent that marine mammal fitness would be affected. As
stated in the proposed Federal Register notice (90 FR 38104, August 7,
2025), our review of the available information and the specific nature
of the activities considered herein suggest that the specified
activities are not likely to have more than temporary adverse effects
on any prey habitat or populations of prey species. Further, any
impacts to prey species are not expected to result in significant or
long-term consequences for individual marine mammals, or to contribute
to adverse impacts on their populations. The commenter does not provide
evidence to the contrary. We have appropriately considered effects to
marine mammal habitat and, as discussed in response to comment 1, the
concerns raised by the commenter do not present extraordinary
circumstances that would invalidate NMFS use of the CatEx in this
circumstance.
Comment 3: Commenters expressed concern regarding the effects of
incidental takes on certain species of marine mammals based on what the
commenters describe as other threats these species face in the region,
and state that NMFS should deny the requested authorization on this
basis.
Response: Along varying ranges of the Atlantic coast, there have
been ongoing Unusual Mortality Events (UMEs) for North Atlantic right
whales, humpback whales, and minke whales, which includes animals
stranded since 2017, 2016, and 2017, respectively. We provide further
information on these UMEs in the Description of Marine Mammals in the
Area of Specified Activities section of the proposed IHA (August 7,
2025, 90 FR 38104).Ongoing UMEs for humpback and minke whales do not
provide meaningful cause for concern at the population level for these
marine mammal stocks. Far from indicating that these species are in
crisis, as is suggested by commenters stating that no takes should be
authorized for these species, these species are healthy, with estimated
population abundance exceeding 10,000 and 20,000 animals, respectively.
For North Atlantic right whales, while we agree that the species faces
significant threats, primarily from vessel strike and entanglement in
fishing gear, we do not agree with the suggestion that the population
cannot sustain 12 incidents of Level B harassment, which are likely to
be relatively low-level, temporary behavioral reactions with no lasting
significance for the impacted individuals.
As described in this notice of final IHA, NMFS finds that small
numbers of marine mammals may be taken relative to the population size
of the affected species or stocks and that the incidental take of
marine mammal from Transco's specified activities will have a
negligible impact on all affected marine mammal species or stocks.
Comment 4: A commenter states that modeling and past monitoring
data are not adequate to assess real-time presence of at-risk species,
and do not consider seasonal fluctuations in population density, and as
such, asserts that the precautionary principle demands stricter
mitigation or deferral is necessary to ensure effective protections.
Response: NMFS is required to issue the requested ITA if the
necessary findings are made based on the best scientific information
available (16 U.S.C. 1371(a)(5)(A)(i)). In this case, NMFS considered
the best available marine mammal density data, published and peer
reviewed scientific literature, on-the-water reports from other nearby
projects and monitoring from past MMPA actions in the area. Seasonal
fluctuations in population density have been accounted for in the
density analysis, as the mean density across the total project period
was compared to the mean density across the year and the largest value
was the selected input calculating take estimates. The commenter did
not provide additional scientific information regarding marine mammal
presence for NMFS to consider. The commenter did not provide evidence
to support the claim that the mitigation measures are not sufficient to
affect the least practicable impact on the species or stock and its
habitat and did not recommend additional mitigation measures for NMFS
to consider.
Comment 5: A commenter suggests that the required length of time to
conduct re-detection monitoring should be extended before work
recommences,
[[Page 45733]]
referencing. Smith et al., 2022, which reports humpback whales lunge-
feeding in shallow waters including in the project area.
Response: Given the evidence presented, in which humpback whales
have been documented lunge feeding in shallow habitats, including in
the project area, NMFS agrees that an increase in re-detection
monitoring to 30 minutes following a shutdown is reasonable for low
frequency cetaceans and has revised relevant mitigation measures.
Comment 6: Commenters suggest that the proposed mitigation
requirements are inadequate, including a statement that the proposed
requirements do not ``establish adequate safeguard thresholds or clear
criteria for halting operations.'' A commenter states that Transco must
be required to follow the same mitigation and monitoring requirements
that have been included in certain ITAs (e.g., offshore wind project
construction), while another commenter specifically recommends that
NMFS require use of passive acoustic monitoring (PAM), and state that
NMFS should restrict pile driving to within seasonal windows when
marine mammals are less abundant and should ``develop clear,
enforceable, operational triggers requiring immediate shutdown upon
detection of protected species''. The commenter also claims the IHA
lacks transparent adaptive management measures.
Response: The commenters have not provided evidence to support
their conclusion that the proposed mitigation measures are not
sufficient to affect the least practicable adverse impact on species or
stocks and their habitat. NMFS first emphasizes that mitigation
measures are specified activity specific and designed to mitigate
specific effects. Thus, mitigation measures included in one ITA may not
be appropriate for another ITA (e.g., sound related mitigation measures
for pile driving of offshore wind turbine foundations versus measures
for pile driving temporary piles with a maximum diameter of 1.5 m).
Implementation of noise attenuation devices and sound field
verification would be costly and logistically challenging given the
nature of the activity, in which Transco plans to vibratory install 163
piles along a string at 8 locations in 43 days and removing the same
piles in 26 days, and impact installing 34 piles along a string at 3
locations separated by >20 km in some instances. Such measures would
likely increase project costs and create delays. NMFS is not requiring
a dedicated PSO vessel because the IHA requires PSOs to monitor from
each pile driving location and the shutdown zones are reliably
observable from this location. In addition to complying with existing
vessel speed restrictions for North Atlantic right whales, NMFS
highlights that Transco also intends to comply with voluntary programs
NMFS uses to notify vessel operators to slow down to avoid right
whales. Transco has agreed to adhere to rules for DMAs if they are
designated by NMFS in the project area during the project, which could
be established any time of year; as such, should a DMA be established
outside of the SMA, Transco has indicated they will voluntarily comply.
NMFS does not find it reasonable to require that Transco adhere to
vessel speed restrictions outside these programs designed to protect
right whales, given the relatively low occurrence of this species, as
well as other low-frequency cetaceans, in the project area.
While we acknowledge that use of PAM provides utility for detection
of vocalizing marine mammals that may not be detected by visual
observers, development and implementation of such systems carry
meaningful operational costs. Use of PAM systems as a component of an
overall monitoring approach has been included as a requirement in
certain incidental take authorizations with greater expected potential
for impacts to marine mammals, e.g., multi-year offshore pile driving
associated with wind energy development. However, for activities with
lower expected potential for impacts to marine mammals, including more
typical inshore coastal construction actions of shorter duration
similar to what is planned by Transco, use of PAM is not a typical
requirement due to the costs of operation relative to the expected
benefits of the addition of what is expected to be a relatively limited
incremental addition in terms of monitoring capability in this context,
e.g., inshore, daylight only, and with relatively small harassment
zones for impact pile driving. Therefore, NMFS is not requiring Transco
to implement PAM.
The commenters do not provide a recommended time of year or suggest
which species should be prioritized in establishing seasonal
restrictions. Migrating North Atlantic right whales are most likely to
be in the project area between November and April while other species
that may reasonably be considered as priorities for protection are more
likely to occur in the spring and summer months. Additionally, harbor
porpoises are expected to occur in highest densities in the spring and
fall while pinnipeds are expected to occur in the winter and spring
only. Transco intends to complete pile driving activities June through
November when North Atlantic right whale and pinniped occurrences are
less likely to be in the project area. NMFS disagrees that a time of
year restriction is necessary to affect the least practicable adverse
impact on marine mammals.
It is unclear what the commenter means by developing clear,
enforceable operational triggers requiring immediate shutdown upon
detection of protected species. The establishment and implementation of
shutdown zones are described in the shutdown zone and pre and post
activity monitoring headings of the Mitigation sections in the proposed
Federal Register notice (90 FR 38104, August 7, 2025) and herein.
Regarding the commenter's concern about a lack of detail regarding
shutdown implementation, NMFS has further explained that process here.
In the event that pile driving is underway when a marine mammal is
observed entering or within the shutdown zone, pile driving must be
halted. In the event that pile driving is not currently underway (e.g.,
at the beginning of a work day, when a pile is being positioned for
driving, etc.) when a marine mammal is observed entering or within the
shutdown zone, pile driving must be delayed (i.e., not begin). For both
scenarios, pile driving cannot begin (in the case of a delay) or resume
(in the case of a halt) until either the animal has voluntarily exited
and been visually confirmed beyond the shutdown zone or the required
amount of time has passed without re-detection of the animal. NMFS
expects that in coastal environments where the water is relatively
shallow and therefore, most marine mammal dives are generally shorter,
15 minutes is sufficient to conclude that most animals are no longer
within the shutdown zone. In the case of large whales, NMFS has
extended the re-detection monitoring period to 30 minutes, to account
for humpback whale lunge-feeding behavior reported in the project area
(Smith et al., 2022). The protocol for pausing activities based on
real-time evidence of injury or death of a marine mammal, in which it
is apparent that the death or injury is caused by the specified
activity, is described in the reporting section of the IHA.
Adaptive management is not typically included in IHAs because of
their short effective period (contrast incidental take regulations and
associated letters of authorizations that may be effective for up to
five years).
Comment 8: NYDEC recommends revisions to reporting requirements to
[[Page 45734]]
ensure that any sightings of cetaceans be shared with local stranding
network partners as soon as feasible. NYDEC points to the chance of
stranding(s) and/or out of habitat movement subsequent to project
activities, to suggest that local awareness (i.e., the states of New
York and New Jersey and the federally permitted stranding response
groups in each state) of (potentially) at-risk animals should be
prioritized via near real-time communications. Specifically NYDEC
requests that: (1) as soon as feasible and by the end of the day,
report North Atlantic right whale sightings to NMFS at 866-755-6622
and, (2) as soon as feasible and by the end of the day, report all
cetacean sightings to the above referenced NMFS hotline and the local
state stranding hotlines.
Response: NMFS agrees that it is reasonable for Transco to report
North Atlantic right whale sightings to the NOAA/GARFO hotline and has
added a requirement to the IHA to ensure that this is reported
immediately and no longer than 24 hours after the sighting rather than
the end of the day, as well as the RWSAS or through the Whale Alert
App.
NMFS also notes that Transco is required to report discoveries of
injured or dead marine mammals to the Office of Protected Resources
(OPR), and to the Northeast Marine Mammal and Sea Turtle Entanglement
Hotline (866-755-6622) (noting that this hotline is a revised contact
based on a request from GARFO, as the hotline provides continuous
coverage throughout the region, and reports are collected by a NOAA
biologist who would relay the report to the local stranding agreement
holder as appropriate). NMFS does not find it appropriate to require
direct reporting of any cetacean in any condition to the above
reference hotline or local stranding hotlines on a daily basis. No
serious injury or mortality is anticipated or proposed to be authorized
for this activity, even in the absence of required mitigation measures,
and such a measure would unnecessarily utilize Transco, NMFS, and local
stranding network resources.
Comment 9: In addition to consulting with Whale Alert, Whale Map,
RWSAS, and VHF Ch. 16 as currently required, a commenter recommends
that Transco also consult non-publicly available sources to enhance
awareness of marine mammal presence in the project area. Sources
highlighted include location stranding response groups, whale watching
companies, research teams and relevant state offices to facilitate the
exchange of knowledge of the most recent marine mammal sightings within
and just outside the project area.
Response: NMFS does not agree that the addition of the non-publicly
available sources of information suggested by the commenter would
result in improved awareness and information exchange beyond what will
be achieved with the listed media and through Transco's requirements to
report any North Atlantic right whale and any injured or dead marine
mammal to the hotline. The existing requirements are considered
comprehensive. For example, there is usually only a 24-hour lag between
North Atlantic right whale reports and website updating on Whale Map,
and the Northeast Marine Mammal and Sea Turtle Entanglement Hotline
(866-755-6622) provides continuous coverage throughout the region, and
reports are collected by a NOAA biologist who would relay the report to
the local stranding agreement holder, as appropriate.
Comment 10: A commenter requests more details regarding soft-start
procedures such as the time period over which the three sets of strikes
occur, the reduced energy level, and how long after the complete soft
start procedure does impact pile driving occur.
Response: NMFS thanks the commenter for its support of the soft
start measure and its implementation at the start of impact pile
driving on each day and at any time following cessation of impact pile
driving for a period of 30 minutes or longer. Soft-start procedures are
used 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. During a soft start for
construction activities, NMFS requires a 30-second waiting period
between reduced-energy strike sets. In the past, NMFS required a 1-
minute waiting period between reduced-energy strike sets. PSOs reported
that, in some cases, the 1-minute interval was too long, and marine
mammals would leave the area but would return during the 1-minute quiet
period. Therefore, the soft start measure was not accomplishing its
intended effect, as marine mammals would not have left the area prior
to the hammers operating at full capacity. Therefore, in this final
IHA, NMFS continues to require a 30-second waiting period between
reduced-energy strike sets during soft starts. As such, the soft start
procedures should take about 60 seconds from first set to the third set
and pile driving should commence within 90 seconds of the first soft-
start set. Transco has indicated they will reduce strikes to a 25
percent capacity level for the initial strikes.
Comment 11: Commenters provide concerns regarding the proposed
authorization of take for North Atlantic right whales. A commenter
stated that such authorization does not meet the MMPA's ``least
practicable adverse impact'' standard and, therefore, that shutdowns
must be implemented when any large whale is present within the Level B
harassment zones.
Similarly, a commenter expresses concern by noting that the
Potential Biological Removal (PBR) is less than 1 and that no North
Atlantic right whale can be lost; that its resilience to future
perturbations is expected to be low, that harassment can have
population impacts, and that increased shipping traffic during
construction pose a risk to North Atlantic right whale from both vessel
strikes and underwater noise. The commenter recommends that NMFS deny
authorization of all North Atlantic right whale takes.
Response: We first note that commenters erroneously conflate the
loss of individual right whales with the effects of behavioral
harassment. The low-level, temporary instances of Level B harassment
authorized through the IHA are not expected to cause energetic effects
to the affected individuals, much less cause population-level impacts
as would be required to reach the conclusions of commenters that the
take of North Atlantic right whales contemplated here should not be
authorized.
The MMPA requires that we include measures that will affect the
least practicable adverse impact on the affected species and stocks
and, in practice, NMFS agrees that the IHA should include conditions
for the construction activities that will first avoid adverse effects
on North Atlantic right whales in and around the project area, where
practicable, and then minimize the effects that cannot be avoided.
No serious injury or mortality is anticipated or authorized. The
project is planned to occur between June and November when North
Atlantic right whales are less likely to be in the project area. Take
by Level B harassment has been requested and authorized for North
Atlantic right whales to account for potential for schedule shifts.
NMFS has determined that this final IHA meets this requirement to
effect the least practicable adverse impact.
NMFS is required to authorize the requested incidental take if it
finds such incidental take of small numbers of marine mammals by the
requestor while engaging in the specified activities
[[Page 45735]]
within the specified geographic region will have a negligible impact on
such species or stock and where appropriate, will not have an
unmitigable adverse impact on the availability of such species or stock
for subsistence uses. As described in this notice of final IHA, NMFS
finds that small numbers of marine mammals may be taken relative to the
population size of the affected species or stocks and that the
incidental take of marine mammal from Transco's specified activities
will have a negligible impact on all affected marine mammal species or
stocks.
Comment 12: Two commenters question the need for the project, with
one calling for re-evaluating the project necessity and exploration of
less invasive alternatives of technologies, and the other suggesting
that the tangible benefits do not outweigh the cost of disturbing
natural resources.
Response: NMFS is not authorizing the specified activities; rather,
it is authorizing the take of marine mammals incidental to those
activities. The MMPA requires that upon request, NMFS, as delegated by
the Secretary of Commerce, issue an ITA if necessary findings are made
(e.g., negligible impact) and to prescribe (1) methods of taking
pursuant to the specified activities, (2) means of effecting the least
practicable adverse impact on marine mammals and their habitat (i.e.,
mitigation measures), and (3) monitoring and reporting measures (16
U.S.C. 1371(a)(5)(A)(i)).
Changes From the Proposed IHA to the Final IHA
NMFS made corrections to several tables to address typographical
errors. In table 6 of the proposed IHA Federal Register notice (90 FR
38104, August 7, 2025), the sound level (SPLrms) for vibratory
installation of 60-in (1.5 m) steel piles was incorrectly listed as 193
dB. This typographical error has been corrected here in table 4 to
clarify that the sound level analyzed is 195 dB. In table 7 of the
proposed IHA Federal Register notice, under pile removal, the contents
of ``piles per day'' and ``duration to drive a single pile'' columns
were reversed for all piles. These typographical errors have been
corrected here in table 5. In table 9 of the proposed IHA Federal
Register notice, the Level B harassment isopleths (m) listed for
vibratory installation of 48-in (1.2 m) steel, impact installation of
36-in (0.9 m) steel, and concurrent impact installation of two 36-in
(0.9 m) steel piles were misarranged. These typographical errors have
been corrected here in table 7 and in table 4 of the IHA. Also, in
table 9 of the proposed IHA Federal Register notice, the Level A
harassment zone (km\2\) for low frequency cetaceans during impact
installation of 34-in (0.9 m) steel pile at MP 34.5/35.04 was
misidentified. This typographical error has been corrected here in
table 7. NMFS confirms that these were typographical errors and that
the correct values were used in analysis in all cases. Given that the
information used in the analysis did not change, these corrections do
not change NMFS' analysis, findings, or determinations.
NMFS also corrected the IHA to require that injured and dead marine
mammals be reported to the Northeast Marine Mammal and Sea Turtle
Stranding and Entanglement Hotline (866-755-6622) rather than the
Greater Atlantic Region/New England and Regional Stranding Coordinators
that were listed in the proposed IHA.
In addition, NMFS has added clarifying language to certain IHA
requirements: (1) Item 5.C. has been revised to specify that four PSOs
would be employed at a pile driving location during concurrent pile
driving, to meet the requirement of two PSOs being assigned at each
active pile driving site; (2) Item 6.c.ii. of the IHA has been revised
to specify that the combination of piles used during concurrent pile
driving should be reported.
NMFS has also revised the IHA to include clarifications to proposed
mitigation, monitoring, and/or reporting measures: (1) Item 6.c.v. of
the IHA has been revised to include a requirement that Transco report
whether/what mitigation is implemented for each marine mammal sighting,
which was inadvertently omitted from the proposed IHA; and, (2) Transco
must report any observations of North Atlantic right whales to NMFS and
Right Whale Sightings Advisory System, or WhaleAlert. The report should
include the time, date, and location of the sighting, number of whales,
animal description/certainty of sighting (provide photos/video if
taken), and PSO/reporter's contact information, and (3) as a result of
public comment, Item 4 (e) of the IHA has been revised to increase the
timeframe that monitoring must be conducted following a shutdown or
delay due to the presence of a marine mammal within a shutdown zone, to
30 minutes for low-frequency cetaceans.
Transco agreed that these revised mitigation measures are
practicable and monitoring and reporting measures are appropriate.
NMFS has made these adjustments in the final IHA. These changes do
not affect our analysis, findings, or determinations.
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; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 1 lists all species or stocks for which take is expected and
authorized for this activity and summarizes information related to the
population or stock, including regulatory status under the MMPA and ESA
and 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 neither anticipated nor authorized
here, PBR and annual serious injury and mortality (M/SI) 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 SARs. All values presented in table 1 are the most
recent available at the time of publication (including from the draft
2024 SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
[[Page 45736]]
Table 1--Species \1\ With Estimated Take From the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\2\ abundance survey) \3\ SI\4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
N Atlantic Right Whale \5\...... Eubalaena glacialis.... Western Atlantic....... E, D, Y 372 (0, 367, 2023).... 0.73 14.8
Family Balaenopteridae (rorquals):
Fin Whale....................... Balaenoptera physalus.. Western N Atlantic..... E, D, Y 6,802 (0.24, 5,573, 11 2.05
2021).
Humpback Whale.................. Megaptera novaeangliae. Gulf of Maine.......... -, -, N 1,396 (0, 1380, 2016). 22 12.15
Minke Whale..................... Balaenoptera Canadian Eastern -, -, N 21,968 (0.31, 17,002, 170 9.4
acutorostrata. Coastal. 2021).
Sei Whale....................... Balaenoptera borealis.. Nova Scotia............ E, D, Y 6,292 (1.02, 3,098, 6.2 0.6
2021).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Long-Finned Pilot Whale \6\..... Globicephala melas..... Western N Atlantic..... -, -, N 39,215 (0.30, 30,627, 306 5.7
2021).
Short-Finned Pilot Whale \7\.... Globicephala Western N Atlantic..... -, -, Y 18,726 (0.33, 14,292, 143 218
macrorhynchus. 2021).
Atlantic Spotted Dolphin........ Stenella frontalis..... Western N Atlantic..... -, -, N 31,506 (0.28, 25,042, 250 0
2021).
Atlantic White-Sided Dolphin.... Lagenorhynchus acutus.. Western N Atlantic..... -, -, N 93,233 (0.71, 54,443, 544 28
2021).
Bottlenose Dolphin.............. Tursiops truncatus..... Northern Migratory -, -, Y 6,639 (0.41, 4,759, 48 12.2-21.5
Coastal. 2016).
Western N Atlantic -, -, N 64,587 (0.24, 52,801, 507 28
Offshore \8\. 2021).
Common Dolphin.................. Delphinus delphis...... Western N Atlantic..... -, -, N 93,100 (0.56, 59,897, 1,452 414
2021).
Family Phocoenidae (porpoises):
Harbor Porpoise................. Phocoena phocoena...... Gulf of Maine/Bay of -, -, N 85,765 (0.53, 56,420, 649 145
Fundy. 2021).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
Gray Seal \9\................... Halichoerus grypus..... Western N Atlantic..... -, -, N 27,911 (0.20, 23,624, 1,512 4,570
2021).
Harbor Seal..................... Phoca vitulina......... Western N Atlantic..... -, -, N 61,336 (0.08, 57,637, 1,729 339
2018).
Harp Seal....................... Pagophilus Western N Atlantic..... -, -, N 7.6M (UNK, 7.1M, 2019) 426,000 178,573
groenlandicus.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>).
\2\ Endangered Species Act 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.
\3\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ 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. A
CV associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ The current SAR includes an estimated population (Nest 372) based on sighting history through November 2023. In October 2024, NMFS released a
technical report identifying that the North Atlantic right whale population size based on sighting history through 2023 was 372 whales, with a 95
percent credible interval ranging from 360 to 383 (Linden, 2024). Total annual average observed North Atlantic right whale mortality during the period
2018-2022 was 5.45 animals and annual average observed fishery mortality was 3.95 animals. Numbers presented in this table (14.8 total mortality and
10.8 fishery mortality) are 2018-2022 estimated annual means, accounting for undetected mortality and serious injury.
\6\ Key uncertainties exist in the population size estimate for this species, including uncertain separation between short-finned and long-finned pilot
whales, small negative bias due to lack of abundance estimate in the region between U.S. and the Newfoundland/Labrador survey area, and uncertainty
due to unknown precision and accuracy of the availability bias correction factor that was applied.
\7\ A key uncertainty exists in the population size estimate for this species based upon the assumption that the logistic regression model accurately
represents the relative distribution of short-finned vs. long-finned pilot whales.
\8\ Estimates may include sightings of the coastal form.
\9\ NMFS' stock abundance estimate (and associated PBR value) applies to the U.S. population only. Total stock abundance (including animals in Canada)
is approximately 394,311. The annual M/SI value given is for the total stock.
As indicated above, all 15 species (with 16 managed stocks) in
table 1 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur.
In addition to what is included in sections 3 and 4 of the IHA
application, and NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>), further detail informing the regional occurrence for select
species of particularly or unique vulnerability (i.e., information
regarding ESA listed or MMPA depleted species, information regarding
current UMEs and known important habitat areas such as Biologically
Important Areas (BIAs)) (Van Parijs, 2015) were provided in the Federal
Register notice for the proposed IHA (90 FR 38104, August 7, 2025).
Since publication of the notice of proposed IHA, we are not aware of
any new relevant information; therefore, detailed descriptions are not
provided here. Please refer to the Federal Register notice (90 FR
38104, Aug. 7, 2025) for these descriptions.
[[Page 45737]]
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.). Generalized hearing ranges were
chosen based on the ~65 decibel (dB) threshold from composite
audiograms, previous analyses in NMFS (2018), and/or data from Southall
et al. (2007) and Southall et al. (2019). We note that the names of two
hearing groups and the generalized hearing ranges of all marine mammal
hearing groups have been recently updated (NMFS 2024) as reflected
below in table 2.
Table 2--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz.
whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
Very High-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 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 may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS 2018, and/or data from Southall et al. 2007; Southall
et al. 2019. Additionally, animals are able to detect very loud sounds
above and below that ``generalized'' hearing range.
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
The effects of underwater noise from Transco's specified activities
have the potential to result in behavioral harassment, and, in limited
cases, an auditory threshold shift (TS), of marine mammals in the
vicinity of the project area. The notice of proposed IHA (90 FR 38104,
Aug. 7, 2025) included a discussion of the effects of anthropogenic
noise on marine mammals and the potential effects of underwater noise
from Transco's specified activity on marine mammals and their habitat.
NMFS is not aware of any new relevant information. Therefore, a
discussion of potential effects is not repeated here; please refer to
the Federal Register notice of the proposed IHA (90 FR 38104, Aug. 7,
2025).
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
authorized through the IHA, which informed NMFS' consideration of
``small numbers,'' the negligible impact determinations, and impacts on
subsistence uses.
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 are primarily by Level B harassment, as use of the
acoustic source/s (i.e., impact and vibratory pile driving and removal)
has the potential to result in disruption of behavioral patterns for
individual marine mammals. There is also some potential for auditory
injury (AUD INJ) (Level A harassment) to result for all hearing groups.
However, the planned 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 authorized for this activity. Below we describe how the
authorized take numbers were estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes there is
some reasonable potential for marine mammals to be behaviorally
harassed or incur some degree of AUD INJ; (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 authorized
take estimates.
Acoustic Criteria
NMFS recommends the use of acoustic criteria 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 AUD INJ of some degree (equated to
Level A harassment). We note that the criteria for AUD INJ, as well as
the names of two hearing groups, have been recently updated (NMFS 2024)
as reflected below in the Level A harassment section.
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
[[Page 45738]]
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
(root mean square, 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 planned activity includes the use of continuous
(vibratory pile driving and removal) and impulsive (impact pile
driving) sources, and therefore the RMS SPL thresholds of 120 and 160
dB re 1 [mu]Pa are applicable.
Level A Harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to
assess AUD INJ (Level A harassment) to five different underwater 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 planned activity includes the use of impulsive (impact pile
driving) and non-impulsive (vibratory pile driving and removal)
sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. The
thresholds are provided in the table below. The references, analysis,
and methodology used in the development of the criteria are described
in NMFS' 2024 Updated Technical Guidance, which may be accessed at:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>.
Table 3--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW); (Underwater).... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW); (Underwater)... Cell 9: Lpk,flat: 230 dB; Cell 10: LE,OW,24h: 199 dB.
LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [micro]Pa\2\s. In this table, criteria are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
hearing range of marine mammals underwater (i.e., 7 Hertz (Hz) to 165 Kilohertz (kHz)). The subscript
associated with cumulative sound exposure level criteria indicates the designated marine mammal auditory
weighting function (LF, HF, and VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation
period is 24 hours. The weighted cumulative sound exposure level criteria 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 criteria 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 planned project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., vibratory pile driving and
removal, and impact pile driving).
The project includes vibratory pile installation and removal, and
impact pile driving. Since there would be many piles at each of the
eight construction sites within close proximity to one another, Transco
found, and NMFS agreed, that it was not practical to estimate
harassment zones for each individual pile at specific locations and
results would have been nearly identical for all similarly sized piles
at each construction location. In order to simplify calculations, a
representative pile site was selected for the eight separate pile
locations (figure 1). For strings where only a single pile type would
be installed or removed (i.e., Neptune Power Cable Crossing MP 13.84
and MP 35.04, MP 14.5 to MP 16.5, MP 28 to MP 29.36, and MP 34.5 to MP
35.04), Transco selected a representative location in the middle of the
string. For the Morgan Shore Approach HDD string site, Transco selected
the location closest to the platform installation as the representative
pile location because it represents the area with the largest pile
sizes. At the HDD Ambrose West Side and HDD Ambrose East Side
locations, Transco's representative pile locations were selected based
on the entry and exit pits. The HDD Ambrose East Side is the entry pit
and the HDD Ambrose West Side is the exit pit. This would also
represent the outer limit of the HDD Ambrose string, and is therefore
the most conservative modeling option.
In its application, Transco indicated that it identified source
levels for installation and removal of each pile type and size using
the compendium
[[Page 45739]]
compiled by Caltrans 2015, but also referenced Caltrans, 2020 and
Illingworth & Rodkin, 2017. Transco did not specify which sound levels
were based on which reference. NMFS revised source levels for these
activities based on reviews of measurements of the same or similar
types and dimensions of piles available in the literature (table 4).
NMFS and Transco assumed that the representative sound source levels
were based on the largest pile expected to be driven/removed at each
potential in-water construction site. For example, where Transco may
use a range of pile sizes (i.e., 36 to 48-in (0.9 to 1.2 m) piles), the
largest potential pile size (48-in (1.2 m)) was used in modeling.
Source levels for vibratory installation and removal are assumed to be
the same.
Additionally, while not included in its application, Transco
indicated that two hammers, including a combination of vibratory and
impact hammers, may operate simultaneously at three out of eight
locations. As such, source levels for the combination of piles that
would create the largest cumulative sound exposure level at location
are also presented in table 4.
The methods for how the source levels for these concurrent
activities are derived are described here: When two noise sources have
overlapping sound fields, the sources are considered additive and
combined using the rules of dB addition. For addition of two
simultaneous sources, the difference between the two sound source
levels is calculated, and if that difference is between 0 and 1 dB, 3
dB are added to the higher sound source levels; if the difference is
between 2 and 3 dB, 2 dB are added to the highest sound source levels;
if the difference is between 4 and 9 dB, 1 dB is added to the highest
sound source levels; and with differences of 10 or more dB, there is no
addition. For two simultaneous sources of different type (i.e., impact
and vibratory driving), there is no sound source addition. In such
cases, the isopleth associated with the individual source which results
in the largest isopleths is conservatively used for both sources to
account for periods of overlapping activities.
Table 4--Estimates of Mean Underwater Sound Levels \1\ Generated During Vibratory and Impact Pile Driving and Vibratory Removal of Temporary Steel Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile size
Method (inches) dB RMS dB Peak dB SEL References
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory............................ 10 155 N/A N/A Caltrans 2015.
24 157 N/A N/A Caltrans 2020.
34 170 N/A N/A Caltrans 2015.
36 170 N/A N/A Caltrans 2015.
48 170 N/A N/A NMFS 2024.\2\
60 170 N/A N/A NMFS 2024.\2\
Impact............................... 34 193 210 183 Caltrans 2015, Caltrans 2020.
36 193 210 183 Caltrans 2015, Caltrans 2020.
60 195 210 185 Caltrans 2020.
Impact, Impact \3\................... 36, 36 196 213 183 Caltrans 2015.
Impact, Vibratory.................... 60, 48 170 210 185 Caltrans 2020.
Vibratory, Vibratory \3\............. 48, 48 173 N/A N/A NMFS 2024.\2\
36, 36 173 N/A N/A
36, 48 173 N/A N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.
\1\ All sound levels are referenced at 10 m.
\2\ Refers to a NMFS compendium of recommended source level proxies.
\3\ Source levels adjusted following rules of dB addition described above.
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 x Log10 (R<INF>1</INF>/R<INF>2</INF>),
where:
TL = transmission loss in dB
B = transmission loss coefficient
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement
Absent site-specific acoustical monitoring with differing measured
TL, a practical spreading value of 15 is used as the TL coefficient in
the above formula. Site-specific TL data for the New York Bight are not
available; therefore, the default coefficient of 15 is used to
determine the distances to the Level A harassment and Level B
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 2024 Updated 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 pile driving and removal, 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 AUD INJ. Inputs used in the optional User Spreadsheet
tool, and the resulting estimated isopleths, are reported in tables 5
and 6.
To calculate Level A harassment isopleths for two impact hammers
operating simultaneously, the NMFS User Spreadsheet calculator was used
with modified inputs to account for the total estimated number of
strikes for all piles. For simultaneous impact pile driving of two 36-
in (0.9 m) steel piles (the most conservative scenario identified at
Morgan Shore Approach HDD MP 12.59), the total estimated number of
strikes per day was summed
[[Page 45740]]
to estimate total sound exposure during simultaneous installation, and
the number of piles per day was reduced to one. The source level for
two simultaneous impact hammers was not adjusted because for identical
sources the accumulation of energy depends only on the total number of
strikes, whether or not they overlap fully in time.
To calculate the Level A harassment isopleths for one impact and
one vibratory hammer operating simultaneously, sources were treated as
though they were non-overlapping. The isopleths associated with the
individual source which results in the largest Level A harassment
isopleths were conservatively used for both sources to account for
periods of overlapping activities.
To calculate Level A harassment isopleths for two simultaneous
vibratory hammers, the NMFS User Spreadsheet was used with modified
inputs to account for accumulation, weighting, and source overlap in
space and time. Using the rules of dB addition described above (i.e.,
if the difference between the two source levels is between 0 and 1 dB,
3 dB are added to the higher sound source level), the combined sound
source level for the simultaneous vibratory installation of two 48-in
steel piles, or two 36-in (0.9 m) steel piles, or a 36-in (0.9 m) and a
48-in (1.2 m) steel pile is 173 dB RMS in all cases.
Table 5--User Spreadsheet Inputs--Single Pile Driving Scenarios
----------------------------------------------------------------------------------------------------------------
Weighting Duration to
Spreadsheet tab factor Piles drive a
Location Pile size used adjustment per day single pile Strikes
(kHz) (minutes)
----------------------------------------------------------------------------------------------------------------
Installation
----------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 24 A.1 Vibratory pile 2.5 4 15 N/A
12.59). 36 driving. 4
48 4
36 E.1 Impact pile 2 4 N/A 2,500
driving.
Neptune Power Cable Crossing (MP 10 A.1 Vibratory pile 2.5 4 15 N/A
13.84). driving.
MP 14.5 to MP 16.5.............. 24 A.1 Vibratory pile 2.5 5 15 N/A
driving.
MP 28.0 to MP 29.36............. 34 A.1 Vibratory pile 2.5 4 15 N/A
driving.
HDD Ambrose West Side (MP 29.4). 24 A.1 Vibratory pile 2.5 6 15 N/A
36 driving. 2
48 4
60 2
E.1 Impact pile 2 2 N/A 3,382
driving.
HDD Ambrose East Side (MP 30.48) 24 A.1 Vibratory pile 2.5 5 15 N/A
36 driving. 3
48 8
60 1
MP 34.5 to MP 35.04............. 34 A.1 Vibratory pile 2.5 2 15 N/A
driving.
E.1 Impact pile 2 2 15 2,500
driving.
Neptune PC Crossing (MP 35.04).. 10 A.1 Vibratory pile 2.5 2 15 N/A
driving.
----------------------------------------------------------------------------------------------------------------
Removal
----------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 24 A.1 Vibratory pile 2.5 4 5 N/A
12.59). 36 driving. 8 30
48 3 15
Neptune PC Crossing (MP 13.84).. 10 A.1 Vibratory pile 2.5 4 15 N/A
driving.
MP 14.5 to MP 16.5.............. 24 A.1 Vibratory pile 2.5 11 15 N/A
driving.
MP 28.0 to MP 29.36............. 34 A.1 Vibratory pile 2.5 6 30 N/A
driving.
HDD Ambrose West Side (MP 29.4). 24 A.1 Vibratory pile 2.5 6 5 N/A
36 driving. 3 15
48 8 15
60 8 30
HDD Ambrose East Side (MP 30.48) 24 A.1 Vibratory pile 2.5 22 15 N/A
36 driving. 3
48 8
60 1
MP 34.5 to MP 35.04............. 34 A.1 Vibratory pile 2.5 2 15 N/A
driving.
Neptune PC Crossing (35.04)..... 10 A.1 Vibratory pile 2.5 2 15 N/A
driving.
----------------------------------------------------------------------------------------------------------------
Table 6--User Spreadsheet Inputs: Simultaneous Pile Driving Scenarios
----------------------------------------------------------------------------------------------------------------
Weighting Duration to
Pile sizes Spreadsheet tab factor Piles drive a
Location (inches) and used adjustment per day single pile Strikes
methods (kHz) (minutes)
----------------------------------------------------------------------------------------------------------------
Installation
----------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 36 impact, 36 E.1 Impact pile 2 1 N/A 15,000
12.59). impact. driving.
HDD Ambrose West Side (MP 60 impact, 48 E.1 Impact pile 2 2 N/A 3,382
29.4). vibratory. driving.
HDD Ambrose East Side (MP 48 vibratory, 48 A.1 Vibratory 2.5 1 60 N/A
30.48). vibratory. pile driving.
----------------------------------------------------------------------------------------------------------------
Removal
----------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 36 vibratory, 36 A.1 Vibratory 2.5 1 40 N/A
12.59). vibratory. pile driving.
HDD Ambrose West Side (MP 36 vibratory, 48 A.1 Vibratory 2.5 1 60 N/A
29.4). vibratory. pile driving.
HDD Ambrose East Side (MP 48 vibratory, 48 A.1 Vibratory 2.5 1 60 N/A
30.48). vibratory. pile driving.
----------------------------------------------------------------------------------------------------------------
[[Page 45741]]
NMFS recommends use of Level B harassment thresholds of 160 dB
re1[mu]Pa (rms) for impulsive sounds (e.g., impact pile driving) and
120 dB re1[mu]Pa (rms) for non-impulsive sounds (e.g., vibratory
driving and removal). Based on the predicted source levels associated
with various pile sizes (table 4) the distances from the pile driving/
removal equipment to the Level B harassment thresholds were calculated,
using the distance to the 160 dB threshold for the impact hammer and
the distance to the 120 dB threshold for the vibratory device, at the
representative pile locations (table 7). It should be noted that while
sound levels associated with the Level B harassment threshold for
vibratory driving/removal were estimated to propagate as far as 34,146
m from pile installation and removal activities based on modeling, it
is likely that the noise produced from vibratory activities associated
with the project would be masked by background noise before reaching
this distance, as the Port of New York and New Jersey, which represents
the busiest port on the east coast of the United States and the third
busiest port in the United States, is located near the project area and
sounds from the port and from vessel traffic propagate throughout the
project area. However, take estimates conservatively assume propagation
of project-related noise to the full extent of the modeled isopleth
distance to the Level B harassment threshold. The modeled distances to
isopleths associated with Level B harassment thresholds for impact and
vibratory driving are shown in table 9.
Table 7--Projected Distances to Level A and Level B Harassment Isopleths (m) (and Associated Areas \1\ (km\2\) by Marine Mammal Hearing Group
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment zones (m) (areas km\2\) Level B
Location Pile size Hammer type ----------------------------------------------------------------------- harassment
(inches) LF HF VHF PW zone
--------------------------------------------------------------------------------------------------------------------------------------------------------
Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 24............. Vibratory....... 5 1.9 4.1 6.4 2,929
12.59). 36............. 36.7 14.1 30.0 47.3 21,544
48............. 36.7 14.1 30.0 47.3 21,544
36............. Impact.......... 4,618.4 589.3 7,147.0 4,102.8 1,585
36 and 36...... Impact and 6,052 (34.20) 772 (1.72) 9,365 (59.13) 5,376 (29.19) 2,512
Impact.
Neptune PC Crossing (MP 13.84) 10............. Vibratory....... 3.7 1.4 3.0 4.7 2,154
MP 14.5 to MP 16.5............ 24............. Vibratory....... 5.8 2.2 4.7 7.5 2,929
MP 28.0 to MP 29.36........... 34............. Vibratory....... 36.7 14.1 30.0 47.3 21,544
HDD Ambrose West Side (MP 24............. Vibratory....... 6.5 2.5 5.3 8.4 2,929
29.4). 36............. 23.1 8.9 18.9 29.8 21,544
48............. 36.7 14.1 30.0 47.3 21,544
60............. 23.1 8.9 18.9 29.8 21,544
Impact.......... 4,837.6 617.2 7,486.1 4,297.5 2,154
60 and 48...... Impact and 4,837.6 (72.22) 617.2 (1.20) 7,486.1 (159.37) 4,297.5 (57.63) 34,146 (1,502)
Vibratory.
HDD Ambrose East Side (MP 24............. Vibratory....... 5.8 2.2 4.7 7.5 2,929
30.48). 36............. 30.3 11.6 24.8 39.0 21,544
48............. 58.3 22.4 47.6 75.0 21,544
60............. 14.6 5.6 11.9 18.8 21,544
21,544
48 and 48...... Vibratory and 58.3 22.4 47.6 75.0 34,146 (1,502)
Vibratory.
MP 34.5 to MP 35.04........... 34............. Vibratory....... 23.1 8.9 18.9 29.8 21,544
Impact.......... 2,909.4 (26.59) 371.2 (0.43) 4,502.3 (62.49) 2,584.6 (20.99) 1,585
Neptune PC Crossing (MP 35.04) 10............. Vibratory....... 2.3 0.9 1.9 3.0 2,154 (14.58)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 24............. Vibratory....... 2.4 0.9 2.0 3.1 2,929
12.59). 36............. 92.5 35.5 75.6 119.1 21,544
48............. 30.3 11.6 24.8 39.0 21,544
36 and 36...... Vibratory and 44.4 17.1 36.3 57.2 34,146 (1,539)
Vibratory.
Neptune PC Crossing (MP 13.84) 10............. Vibratory....... 3.7 1.4 3.0 4.7 2,154
MP 14.5 to MP 16.5............ 24............. Vibratory....... 9.8 3.8 8.0 12.6 2,929
MP 28.0 to MP 29.36........... 34............. Vibratory....... 76.4 29.8 62.4 98.3 21,544
HDD Ambrose West Side (MP 24............. Vibratory....... 3.1 1.2 2.6 4.0 2,929
29.4). 36............. 30.3 11.6 24.8 39.0 21,544
48............. 58.3 22.4 47.6 75.0 21,544
60............. 92.5 35.5 75.6 119.1 21,544
36 and 48...... Vibratory and 58.3 22.4 47.6 75.0 34,146
Vibratory.
HDD Ambrose East Side (MP 24............. Vibratory....... 15.6 6.0 12.7 20.0 2,929
30.48). 36............. 30.3 11.6 24.8 39.0 21,544
48............. 58.3 22.4 47.6 75.0 21,544
60............. 14.6 5.6 11.9 18.8 21,544
48 and 48...... Vibratory and 58.3 22.4 47.6 75.0 34,146
Vibratory.
MP 34.5 to MP 35.04........... 34............. Vibratory....... 23.1 8.9 18.9 29.8 21,544
Neptune PC Crossing (35.04)... 10............. Vibratory....... 2.3 0.9 1.9 3.0 2,154
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Only areas relevant for take estimates (the largest Level B harassment zones at each location, and the largest Level A harassment zones associated
with impact pile driving at each location) are presented.
[[Page 45742]]
Level A harassment zones are typically smaller than Level B
harassment zones. However, during impact pile driving, the calculated
Level A harassment isopleth is greater than the calculated Level B
harassment isopleth for low frequency cetaceans, very high-frequency
cetaceans and phocids (however, because all activities are assumed as
potentially occurring on the same day, we functionally reference the
largest Level A and Level B harassment zones for purposes of estimating
take). Calculation of Level A harassment isopleths includes a duration
component, which in the case of impact pile driving, is estimated
through the total number of daily strikes and the associated pulse
duration. For a stationary sound source such as impact pile driving, we
assume here that an animal is exposed to all of the strikes expected
within a 24-hour period. Calculation of a Level B harassment zone does
not include a duration component.
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. Additionally, we describe how the
occurrence information is synthesized to produce a quantitative
estimate of the take that is reasonably likely to occur and authorized.
To estimate take during impact and vibratory pile driving and
removal, Transco first generated an annual average density estimate for
each noise-producing scenario, for each species, using Duke University
Marine Geospatial Ecology Laboratory marine mammal habitat-based
density data (<a href="https://seamap.env.duke.edu/models/Duke/EC/">https://seamap.env.duke.edu/models/Duke/EC/</a>) (Roberts et
al., 2016; Roberts et al., 2023, Roberts et al., 2024). Instead of
generating average annual density estimates for each species for each
noise producing scenario, NMFS subsequently created a single project
area that encompassed the largest Level B harassment zones across each
of the eight project locations. This project area was used as the basis
for generating an annual average density estimate and an average
density estimate between June and November, which corresponds to the
planned project period, for each species. Specifically, in a Geographic
Information System, for each month and each species, the density
rasters were clipped to the polygon representing the above referenced
project area. To generate the annual average density estimate for each
species, the density estimates for each clipped density raster (January
through December) were summed and divided by 12 (table 8). To generate
the average density across June through November, the density values
for each clipped density raster (June through November) were summed and
divided by 6. In both cases, the mean density values for each species
were selected to use as a basis for take estimates.
Table 8--Marine Mammal Density Estimates Generated for the Transco Northeast Supply Enhancement Project Area
----------------------------------------------------------------------------------------------------------------
Mean densities Mean densities (June-
Marine mammal species (January-December) November) animals/100
animals/100 km\2\ km\2\
----------------------------------------------------------------------------------------------------------------
North Atlantic Right Whale.................................... 0.021304616299007 0.0030074206269121
Fin Whale..................................................... 0.034273800129881 0.019738282989868
Humpback Whale................................................ 0.057397781000022 0.032971508482719
Minke Whale................................................... 0.094349173218718 0.027476606940787
Sei Whale..................................................... 0.013016774291886 0.0056379703117625
Pilot Whale spp guild \2\..................................... 0.0010383579896433 0.0010383579896433
Atlantic Spotted Dolphin...................................... 0.012827813937997 0.025403273029717
Atlantic White-Sided Dolphin.................................. 0.1092249846683 0.068747673449369
Bottlenose Dolphin \1\........................................ 5.2491380360819 8.0931224515361
Common Dolphin................................................ 0.9122067405692 0.63518957481269
Harbor Porpoise............................................... 0.8396537609158 0.022988098221005
Seal guild \3\................................................ 8.6582116388505 8.0272698748496
----------------------------------------------------------------------------------------------------------------
\1\ The Duke University density data treats all bottlenose dolphins as a single group and as such are not subset
between the Migratory Coastal stocks and the Offshore stocks by the 20-meter isobath.
\2\ The Duke University density data for pilot whale spp. is not broken up for each species and only a single
density file is available. The density here represents the entire guild and will be the same for the annual
mean or the June to November analysis.
\3\ The Duke University data for pinnipeds is not broken up for each species that could occur and represents the
density for the guild.
In addition to consulting the output of marine mammal habitat-based
density models, NMFS also consulted the following data sets: (1)
Monitoring data associated with Transco's LNYBL Maintenance Project in
Sandy Hook Channel, New Jersey, in which PSO's monitored for marine
mammals on 59 days between mid-July and late October 2024 in Raritan
and Lower New York Bays; and, (2) group sizes derived from NOAA
Atlantic Marine Assessment Program for Protected Species data from 2010
to 2019 shipboard distance sampling surveys (Palka et al., 2021).
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 authorized. Generally, 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-hr period) and the number of construction
days planned. 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 (individuals/km\2\) within the
ZOI. (Note that since densities in Roberts et al. (2023, 2024) are
provided in individuals per 100 square km, they were converted to
individuals per square km for ease of use in generating take
estimates).
ZOI = maximum daily ensonified area to relevant thresholds (km\2\)
To estimate take, Transco initially multiplied the location-
specific annual average density estimates for each
[[Page 45743]]
species by the ZOI associated with each noise-producing activity, by
the number of construction days estimated for each noise-producing
activity (based on pile size and location). Activity-specific take
estimates were then summed to generate an overall take estimate for
each species across the project.
Because any activity could occur on any construction day, NMFS
instead multiplied the density estimate generated for the entire
project area by the largest ZOI associated with each of the eight
project locations by the total number of construction days planned at
each location. The resulting location-specific take estimates were
summed to generate an overall take estimate for each species across the
project. To be conservative, NMFS compared the results using the annual
average density estimate for each species and the average density
estimate for June through November and selected the largest result to
use as the basis for its take authorization.
NMFS used the same equation to calculate take by Level A
harassment, with the ZOIs referring to the largest hearing group
specific Level A harassment zones at each location, during impact pile
driving activities only. Because Transco plans to shut down at
distances greater than the Level A harassment zones during vibratory
activities, only impact pile driving activities were included in
estimates of take by Level A harassment.
The ZOI's and total construction days used in density-based take
analyses are presented in the tables 9 and 10.
Table 9--The ZOI's and Total Construction Days Used in Density-Based Estimates of Take by Level B Harassment
----------------------------------------------------------------------------------------------------------------
Total construction days associated
ZOIs at each representative pile driving with vibratory pile driving
Location location (km\2\) (and associated (installation and removal) \1\ at each
isopleths (m)) representative pile driving location
(and associated isopleths (m))
----------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 373 km\2\ (34,146 m)..................... 21
12.59).
Neptune Power Cable Crossing 15 km\2\ (2,154 m)....................... 4
(MP 13.84).
MP 14.5 to MP 16.5........... 24 km\2\ (2,929 m)....................... 7
MP 28.0 to MP 29.36.......... 761 km\2\ (21,544 m)..................... 5
HDD Ambrose West Side (MP 1502 km\2\ (34,146 m).................... 13
29.4).
HDD Ambrose East Side (MP 1502 km\2\ (34,146 m).................... 14
30.48).
MP 34.5 to MP 35.04.......... 857 km\2\ (21,544 m)..................... 5
Neptune Power Cable Crossing 15 km\2\ (2,154 m)....................... 2
(MP 35.04).
----------------------------------------------------------------------------------------------------------------
\1\ Total construction days have been rounded up.
Table 10--The ZOI's and Total Construction Days Used in Density-Based Estimates of Take by Level A Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
ZOI representing the largest hearing group specific Level A harassment zones (km\2\) at each
location during impact pile driving (and associated isopleths (m) Total construction days
Location -------------------------------------------------------------------------------------------------- associated with impact
LF HF VHF PW pile driving \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 34.2 km\2\ (6,052 m)... 1.72 km\2\ (722 m)... 59.13 km\2\ (9,365 m).. 29.19 km\2\ (5,376 m).. 7
12.59).
HDD Ambrose West Side (MP 72.23 km\2\ (4,838 m).. 1.20 km\2\ (617 m)... 159.37 km\2\ (7,486 m). 57.63 km\2\ (4,298 m).. 4
29.4).
MP 34.5 to MP 35.04.......... 26.59 km\2\ (2,909 m).. 0.43 km\2\ (371 m)... 62.49 km\2\ (4,502 m).. 20.99 km\2\ (2,585 m).. 3
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Total construction days have been rounded up.
Monitoring data reported by PSO's during Transco's LNYBL
Maintenance project in Raritan Bay, Lower New York Bay, and the
Atlantic Ocean, in which PSOs monitored for marine mammals on 59 days
between July and October 2024, were also consulted to inform estimates
of take by Level A harassment.
A total of eight sightings of 10 humpback whales were observed
within 4,000 m of the pile driving source, translating to approximately
one sighting of humpback whales per week. The maximum group size
reported during this project was two humpback whales. As such, NMFS has
authorized take by Level A harassment of one group of two humpback
whales each week that impact pile driving activities are planned (two
weeks). Therefore, NMFS has authorized four takes by Level A harassment
of humpback whale (1 group x 2 humpback whales x 2 weeks of impact pile
driving).
During Transco's LNYBL project, PSOs also reported an average of
six bottlenose or unidentified dolphins each day occurring within 770 m
of the pile driving source, which represents the largest Level A
harassment zones associated with impact pile driving for this project.
As such, NMFS has authorized six takes by Level A harassment for each
construction day that impact pile driving is planned (14 days).
Therefore, NMFS has authorized 84 takes by Level A harassment of
bottlenose dolphins (6 takes of bottlenose dolphins x 14 construction
days = 84 takes by Level A harassment of bottlenose dolphin).
Additional data regarding average group sizes from survey effort in
the region was considered to ensure adequate take estimates are
evaluated. Take estimates for several species were adjusted based on
average group sizes derived from NOAA Atlantic Marine Assessment
Program for Protected Species data from 2010 to 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. The
calculated take estimates were adjusted for species as follows:
<bullet> Pilot whales (long-finned and short-finned): Only one take
by Level B harassment was estimated. Authorized takes were increased to
the average number of pilot whales in a group reported in Palka et al.
2021 (n = 14) and applied to both stocks; and
<bullet> Atlantic spotted dolphin: Only 14 takes by Level B
harassment were estimated. Authorized takes were increased to the
average number of dolphins in a group reported in Palka et al., 2021 (n
= 25).
For bottlenose dolphins, the density data presented by Roberts et
al. (2023, 2024) does not differentiate between
[[Page 45744]]
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. 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 50
percent of the project area occurs in waters shallower than 20 m, the
isobaths at which we expect segregation of these stocks (Garrison et
al., 2017), we assign take to each stock accordingly. Thus, we assume
that 50 percent of the total authorized bottlenose dolphin takes would
accrue to the Western North Atlantic Offshore stock, and 50 percent to
the Western North Atlantic Northern Migratory Coastal stock (table 11).
Finally, takes by Level B harassment are modified to deduct the
amount of take by Level A harassment in order to avoid double-counting
in the estimate of total takes for each species or stock.
Table 11--Take by Stock and Harassment Type and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Level B Level A
Species Stock take take Total take % Stock
authorized authorized authorized
----------------------------------------------------------------------------------------------------------------
North Atlantic Right Whale........... Western Atlantic....... 12 0 12 <3.2
Fin Whale............................ Western North Atlantic. 19 0 19 <1
Humpback Whale....................... Gulf of Maine.......... 29 4 33 <1
Minke Whale.......................... Canadian East Coast.... 53 1 54 <1
Sei Whale............................ Nova Scotia............ 7 0 7 <1
Pilot Whale, Long-finned............. Western N Atlantic..... 14 0 14 <1
Pilot Whale, Short-finned............ Western N Atlantic.....
Atlantic Spotted Dolphin............. Western N Atlantic..... 25 0 25 <1
Atlantic White-sided Dolphin......... Western N Atlantic..... 62 0 62 <1
Bottlenose Dolphin................... Western N Atlantic 2,295 42 2,253 35
Migratory Coastal.
Western N Atlantic 2,296 42 2,254 3.5
Offshore.
Common Dolphin....................... Western N Atlantic..... 518 0 518 <1
Harbor Porpoise...................... Gulf of Maine/Bay of 465 11 465 <1
Fundy.
Gray Seal............................ Western N Atlantic..... 4,868 44 4,912 17.6
Harbor Seal.......................... Western N Atlantic..... ........... ........... ........... 8
Harp Seal............................ Western N Atlantic..... ........... ........... ........... <1
----------------------------------------------------------------------------------------------------------------
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.
The mitigation requirements described in the following were
proposed by Transco in its adequate and complete application or are the
result of subsequent coordination between NMFS and Transco. Transco has
agreed that all of the mitigation measures are practicable. NMFS has
fully reviewed the specified activities and the mitigation measures to
determine if the mitigation measures would result in the least
practicable adverse impact on marine mammals and their habitat, as
required by the MMPA, and has determined the measures are appropriate.
NMFS describes these below as mitigation requirements, and has included
them in the issued IHA.
Vessel Strike Avoidance Measures
In addition to complying with existing vessel speed restrictions
for North Atlantic right whales, Transco intends to comply with
voluntary programs NMFS uses to notify vessel operators to slow down to
avoid right whales. All project related vessels, regardless of size,
will operate at 10 knots (18.5 km/hr) or less when traveling in an SMA
(active in portions of the project area between November 1 and April
30). Additionally, at all times and locations, vessel operators and
crews would use the following protocols:
<bullet> Maintain a vigilant watch for right whales and slow down
or stop the vessel to avoid striking the animal(s);
<bullet> Conform to the regulations prohibiting approach of right
whales closer than 500 yards (460 m) (50 CFR 224.103(c));
<bullet> Adhere to rules for DMAs if they are designated by NMFS in
the project area during the project.
Shutdown Zones
For all pile driving and removal 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
[[Page 45745]]
in anticipation of an animal entering the defined area). Shutdown zones
vary based on the activity type and marine mammal hearing group (tables
12 and 13).
In cases where it would be challenging to detect marine mammals at
the Level A harassment isopleth, (e.g., all hearing groups during
impact pile driving activities), and where shutting down at the Level A
harassment zone would create practicability concerns due to the
distances at which species would need to be detected (e.g., high
frequency cetaceans during impact pile driving), smaller shutdown zones
have been established (table 13).
Construction supervisors and crews, 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 tables 12 and 13, or 30 minutes (low-frequency cetaceans)
or 15 minutes (all other marine mammals) have passed without re-
detection of the animal.
Finally, 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 any harassment zone. If a marine
mammal species for which take is not authorized enters a harassment
zone, all in-water activities will cease until the animal leaves the
zone or has not been observed for at least 30 minutes (low-frequency
cetaceans) or 15 minutes (all other marine mammals). Pile driving will
proceed if the unauthorized species is observed leaving the harassment
zone or if 30 minutes (low frequency cetaceans) or 15 minutes (all
other marine mammals) have passed since the last observation.
Table 12--Shutdown Zones During Vibratory Pile Driving and Removal
----------------------------------------------------------------------------------------------------------------
Shutdown for all
Pile size hearing groups,
Site (inches) Installation or removal method install and removal
(m)
----------------------------------------------------------------------------------------------------------------
Morgan Shore Approach HDD (MP 24............... Vibratory......................... 10
12.59).
36............... Vibratory......................... 120
36, 36........... Vibratory, Vibratory.............. 60
48............... Vibratory......................... 50
Neptune PC Crossing (MP 13.84).. 10............... Vibratory......................... 10
MP 14.5 to MP 16.5.............. 24............... Vibratory......................... 20
MP 28.0 to MP 29.36............. 34............... Vibratory......................... 100
HDD Ambrose West Side (MP 29.4). 24............... Vibratory......................... 10
36............... Vibratory......................... 40
48............... Vibratory......................... 80
36, 48........... Vibratory, Vibratory.............. 80
60............... Vibratory......................... 120
HDD Ambrose East Side (MP 30.48) 24............... Vibratory......................... 20
36............... Vibratory......................... 40
48............... Vibratory......................... 80
48, 48........... Vibratory, Vibratory.............. 80
60............... Vibratory......................... 20
MP 34.5 to MP 35.04............. 34............... Vibratory......................... 30
Neptune PC Crossing (MP 35.04).. 10............... Vibratory......................... 10
----------------------------------------------------------------------------------------------------------------
Table 13--Shutdown Zones During Impact Pile Driving
[m]
----------------------------------------------------------------------------------------------------------------
Hearing group-specific shutdown zones (m)
Location Pile types Activity ---------------------------------------------------
LF HF VHF PW
----------------------------------------------------------------------------------------------------------------
HDD Morgan Offshore (MP 36-in........ Impact......... 2,000 200 200 150
12.59).
36, 36....... Impact, Impact.
60........... Impact.........
HDD Ambrose West Side (MP 60, 48....... Impact,
29.4). Vibratory.
MP 34.5 to MP 35.04......... 34........... Impact.........
----------------------------------------------------------------------------------------------------------------
PSOs
The number and placement of PSOs during all construction activities
(described in the Monitoring and Reporting section) would ensure that
the shutdown zones are generally visible, such that PSOs are reasonably
confident of their ability to observe species at relevant distances.
Transco would employ at least two PSOs at each active pile driving site
during 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. Transco also plans to take measures beyond visual observations to
ensure that they are
[[Page 45746]]
aware of marine mammal locations by monitoring media throughout the day
including, but not limited to, Whale Alert, Whale Map, Right Whale
Sightings Advisory System (RWSAS), and U.S. Coast Guard very high
frequency (VHF) Channel 16 (see Monitoring and Reporting section).
Pre-and-Post-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
would observe the shutdown zones and as much of the harassment zones as
possible 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
for which take is authorized. If the shutdown zone for which take is
authorized 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 take by Level B harassment is authorized is
present in the Level B harassment zone, activities may begin. If work
ceases for more than 30 minutes, the pre-activity monitoring of the
shutdown zones would commence.
Soft Start
The use of soft-start procedures during impact pile driving 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. As such, soft start procedures are
expected to be completed within 60 seconds from the first set to the
third set and pile driving should commence within 90 seconds of the
first soft-start set. Transco will reduce energy levels of strikes to
25 percent during soft start procedures. Soft start is not required
during vibratory pile driving activities.
Based on our evaluation of the applicant's planned measures, as
well as other measures considered by NMFS, NMFS has determined that the
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.
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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
<bullet> Mitigation and monitoring effectiveness.
The monitoring and reporting requirements described in the
following were proposed by Transco in its adequate and complete
application or are the result of subsequent coordination between NMFS
and Transco. Transco has agreed that all of the monitoring and
reporting measures are appropriate. NMFS describes those below as
requirements, and has included them in the issued IHA.
Visual Monitoring
Marine mammal monitoring during pile driving activities must be
conducted by NMFS-approved PSOs in a manner consistent with the
following:
<bullet> PSOs must be independent of the activity contractor (for
example, employed by a subcontractor), and have no other assigned tasks
during monitoring periods;
<bullet> At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization;
<bullet> 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 NMFS-issued take authorization;
<bullet> 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,
<bullet> PSOs must be approved by NMFS prior to beginning any
activity subject to this IHA.
PSOs should also have the following qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction
[[Page 45747]]
operation to provide for personal safety during observations;
<bullet> Writing skills sufficient to prepare a report of
observations including, but not limited to, the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and,
<bullet> 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 would be conducted by trained PSOs positioned at
suitable vantage points to generally be able to observe the entirety of
the shutdown zones. Transco would place at least two PSOs at each
active pile driving site during all pile driving and removal
activities. During concurrent pile driving activities, this would
translate to at least four PSOs being placed within a given location to
conduct monitoring: at least one PSO would monitor each shutdown zone
around each active hammer. An additional PSO would be placed at each
site to monitor the extents of each shutdown zone and beyond. PSOs
would be stationed either on the construction barge or a separate
support vessel. PSOs would monitor for marine mammals 360 degrees
around their respective vessels.
Monitoring would 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.
North Atlantic Right Whale and Other Marine Mammal Awareness
Throughout each day, Transco plans to use available sources of
information on North Atlantic right whale and other marine mammals,
including but not limited to Whale Alert, Whale Map, RWSAS, and U.S.
Coast Guard very high frequency (VHF) Channel 16, to receive
notifications of any marine mammal sightings and information associated
with any DMAs. Maintaining frequent daily awareness of North Atlantic
right whale presence in the area, through Transco's ongoing visual
monitoring efforts and opportunistic data sources (outside of Transco's
efforts), and subsequent coordination for disseminating that
information across project personnel affords increased protection of
North Atlantic right whales and other marine mammals by alerting
project personnel and the marine mammal monitoring team to a higher
likelihood of encountering these species, potentially increasing the
efficacy of mitigation efforts.
Reporting
Transco would 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:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> 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);
<bullet> PSO locations during marine mammal monitoring;
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and other relevant weather
conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
<bullet> 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); (9) Description of any actions implemented in response to
the sighting (e.g., delays, shutdown) and time and location of the
action;
<bullet> Number of marine mammals detected within the harassment
zones, by species; and,
<bullet> Summary 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 Transco must report the
incident to the NMFS Office of Protected Resources (OPR)
(<a href="/cdn-cgi/l/email-protection#1444463a5d40443a597b7a7d607b667d7a734671647b666067547a7b75753a737b62"><span class="__cf_email__" data-cfemail="f1a1a3dfb8a5a1dfbc9e9f98859e83989f96a394819e838582b19f9e9090df969e87">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#d5bca1a5fbb3b9b0b8bcbbb295bbbab4b4fbb2baa3"><span class="__cf_email__" data-cfemail="1c75686c327a70797175727b5c72737d7d327b736a">[email protected]</span></a>) and
Greater Atlantic Regional Fisheries Office (GARFO) Northeast Marine
Mammal and Sea Turtle Entanglement Hotline (866-755-6622) as soon as
feasible. If the death or injury was clearly caused by the specified
activity, the Transco 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. Transco must not resume their activities
until notified by NMFS. The report must include the following
information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animals(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and,
[[Page 45748]]
<bullet> General circumstances under which the animal was
discovered.
North Atlantic Right Whale Reporting
Transco will also report any sightings of North Atlantic right
whales by PSOs or project personnel to NMFS (866-755-6622), and the
Right Whale Sightings Advisory System (RWSAS) or through the WhaleAlert
app. The report must include the time, date, and location of the
sighting, number of whales, animal description/certainty of sighting
(provide photos/video if taken), PSO/personnel name, and reporter's
contact information.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any 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 1, 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 and removal associated with this project, as outlined
previously, have 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 and removal. Potential
takes could occur if individuals are present in the ensonified zone
when these activities are underway.
No serious injury or mortality is expected, even in the absence of
required mitigation measures, given the nature of the activities.
Further, for eight species of marine mammals, no take by Level A
harassment is anticipated, due to the rarity of the species near the
project area. The likelihood of take by Level A harassment occurring is
further reduced implementation of mitigation measures such as shutdown
zones that encompass all or a portion of the Level A harassment zones
(see Mitigation section).
Level A harassment is authorized for humpback whale, minke whale,
bottlenose dolphin, harbor porpoise, and pinnipeds that may occur in
the project area (gray seal, harbor seal, and harp seal). Any take by
Level A harassment is expected to result in, at most, a small degree of
AUD INJ (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.
Additionally, the number of takes by Level A harassment authorized
is very low. NMFS expects no more than 4 takes by Level A harassment
for humpback whale; 1 take by Level A harassment for minke whale; and
11 takes by Level A harassment for harbor porpoise. The authorized
number of takes by Level A harassment for bottlenose dolphin and the
guild of pinnipeds that may occur in the project area are a bit
larger--42 takes and 44 takes, respectively. However, for all hearing
groups, if hearing impairment occurs, it is most likely that the
affected animal would lose only a few dB in its hearing sensitivity.
Due to the small degree anticipated, any AUD INJ potentially 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.
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.
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
[[Page 45749]]
during construction activities to reduce exposure to elevated sound
levels from the project. 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.
The project is also not expected to have significant adverse
effects on affected marine mammals' habitats. 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 the exception of right whales, there are no
habitats of known particular importance to marine mammals), the impacts
to marine mammal habitat are not expected to cause significant or long-
term negative consequences.
There is a BIA for migrating right whales that intersects with the
offshore portion of the project area (LaBrecque et al., 2015; Van
Parijs et al., 2015), but it is active between March and April and
November and December, when most of the project activities are not
planned to occur. This suggests that impacts from the project would
have minimal to no impact on important right whale habitat and would
therefore not affect reproduction and survival. While there are plans
for project activities to occur in November, and Transco has also
accounted for the potential that the project schedule could shift into
any time of year, most of the North Atlantic right whales observed in
the New York Bight, when present, are detected in deeper waters of the
continental shelf, much further offshore (Zoidis et al., 2021; Morrison
and Taggart, 2021, accessed July 25, 2025). Given the nature of
migratory behavior (e.g., continuous path), as well as the low number
of total takes, we anticipate that few, if any, of the instances of
take would represent repeat takes of any individual.
As described above, North Atlantic right, humpback, and minke
whales are experiencing ongoing UMEs, and an ongoing UME for gray and
harbor seals is pending closure. However, we do not expect authorized
takes to exacerbate or compound upon these ongoing and closure pending
UMEs. As discussed above, very little injury is expected or authorized,
and the impact of Level A and Level B harassment takes of these species
will be minimized through the implementation of mitigation measures.
The UMEs do not provide cause for concern regarding population-level
impacts. Moreover, no serious injury or mortality is expected or
authorized. Despite the UMEs, the relevant population of humpback
whales (the West Indies breeding population, or DPS), minke whales, and
relevant pinniped species (gray and harbor seals) remain healthy.
For North Atlantic right whales, no injury as a result of the
project is expected or authorized, and Level B harassment takes of
right whales are expected to be in the form of avoidance of the
immediate area of construction. In addition, the number of authorized
takes by level B harassment are minimal (i.e., 12). As no injury or
mortality is expected or authorized, the authorized takes of right
whales would not exacerbate or compound the ongoing UME in any way.
Finally, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the reproduction or
survival of any individuals, much less these stocks' annual rates of
recruitment or survival. In combination, we believe that these factors,
as well as the available body of evidence from other similar
activities, demonstrate that the potential effects of the specified
activities would have only minor, short-term effects on individuals.
The specified activities are not expected to impact rates of
recruitment or survival and would therefore not result in population-
level impacts.
In summary and as described above, the following factors primarily
support our 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:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> No take by Level A harassment is authorized for seven
species;
<bullet> Take by Level A harassment would be of low severity;
<bullet> Takes by Level B harassment would primarily be in the form
of behavioral disturbance, resulting in avoidance of the project areas
around where impact or vibratory pile driving is occurring, with some
low-level TTS that may limit the detection of acoustic cues for
relatively brief amounts of time in relatively confined footprints on
their populations;
<bullet> The lack of anticipated significant or long-term negative
effects to marine mammal habitat;
<bullet> Effects on species that serve as prey for marine mammals
from the specified activities are expected to be short-term and,
therefore, any associated impacts on marine mammal feeding are not
expected to result in significant or long-term consequences for
individuals, or to accrue to adverse impacts on their populations from
either project;
<bullet> The ensonified areas are small relative to the overall
habitat ranges of all species and stocks, and overlap with known areas
of important habitat is minimal;
<bullet> Transco is required to implement mitigation measures,
including visual monitoring and shutdown zones, to minimize the numbers
of marine mammals exposed to injurious levels of sound.
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 planned monitoring and
mitigation measures, NMFS finds that the total marine mammal take from
the 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 section 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 (see 86 FR
5322, January 19, 2021). Additionally, other qualitative factors may be
considered in the analysis, such as the temporal or spatial scale of
the activities.
For all stocks, except for the Western North Atlantic Migratory
Coastal stock of bottlenose dolphin, the authorized number of takes is
less than one-third of the best available population abundance estimate
(i.e., less than 1 percent for 11 stocks, less than 4 percent for 2
stocks, and less than 18 percent for 2 stocks) (table 11).
The total number of authorized takes for bottlenose dolphins, if
assumed to accrue solely to new individuals of the northern migratory
coastal stock, is 35 percent of the total stock abundance, which is
currently estimated as 6,639.
[[Page 45750]]
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, given their range
extends well beyond the project area, will be harassed by project
activities.
Given that the specified activity will be stationary within an area
not recognized as being of any special significance that would serve to
attract or aggregate dolphins, we therefore conclude 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 activity (including
the mitigation and monitoring measures) and the estimated take of
marine mammals, NMFS 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 ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency ensures 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 OPR
consults internally whenever we propose to authorize take for
endangered or threatened species, in this case with NMFS' GARFO. NMFS
OPR is authorizing take of North Atlantic right whale, fin whale, and
sei whale, which are listed under the ESA.
In 2020, NMFS GARFO concluded consultation pursuant to section 7 of
the ESA with the Federal Energy Regulatory Commission regarding
Transco's proposed Northeast Supply Enhancement Project. That
consultation considered effects of all proposed Federal actions,
inclusive of the proposed issuance of an IHA to Transco. GARFO
concluded that no take, as defined by the ESA, was anticipated to occur
and that NMFS OPR's action was not likely to adversely affect any ESA-
listed marine mammal species.
NMFS OPR requested initiation of section 7 consultation with NMFS
GARFO for the issuance of this IHA. Upon consideration of that request,
NMFS GARFO determined that the conclusions reached in the 2020
consultation remain valid and no additional consultation is necessary
for the current action. Therefore, NMFS has determined that the 2020
consultation sufficiently analyzed the effects of the issuance of an
IHA to Transco.
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 NAO 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 determined that the
issuance of the IHA qualifies to be categorically excluded from further
NEPA review.
Authorization
NMFS has issued an IHA to Transco for the potential harassment of
small numbers of 15 marine mammal species (16 stocks) incidental to the
Northeast Supply Enhancement Project in Raritan Bay, Lower New York
Bay, and the Atlantic Ocean that includes the previously explained
mitigation, monitoring, and reporting requirements.
Dated: September 19, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2025-18424 Filed 9-22-25; 8:45 am]
BILLING CODE 3510-22-P
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