Notice2023-06006
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Construction of Liquefied Natural Gas Platforms Off Louisiana
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
March 23, 2023
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from New Fortress Energy Louisiana FLNG LLC (NFE) for authorization to take marine mammals incidental to construction of liquefied natural gas platforms off Grand Isle, Louisiana. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, one-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorizations and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 88 Issue 56 (Thursday, March 23, 2023)</title>
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[Federal Register Volume 88, Number 56 (Thursday, March 23, 2023)]
[Notices]
[Pages 17538-17553]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-06006]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XC766]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Construction of Liquefied Natural
Gas Platforms Off Louisiana
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from New Fortress Energy Louisiana
FLNG LLC (NFE) for authorization to take marine mammals incidental to
construction of liquefied natural gas platforms off Grand Isle,
Louisiana. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to issue an incidental harassment
authorization (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time, one-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorizations and agency responses will be
summarized in the final notice of our decision.
DATES: Comments and information must be received no later than April
24, 2023.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
<a href="/cdn-cgi/l/email-protection#632a37334d000f0615060d10170a0d06230d0c02024d040c15"><span class="__cf_email__" data-cfemail="b4fde0e49ad7d8d1c2d1dac7c0dddad1f4dadbd5d59ad3dbc2">[email protected]</span></a>.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at <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> without change. All
personal identifying information (e.g., name, address) voluntarily
submitted by the commenter may be publicly accessible. Do not submit
confidential business information or otherwise sensitive or protected
information.
FOR FURTHER INFORMATION CONTACT: Alyssa Clevenstine, Office of
Protected Resources, NMFS, (301) 427-8401. Electronic copies of the
application and supporting documents, as well as a list of the
references cited in this document, may be obtained online at: <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>. In case of problems
accessing these documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has
preliminarily determined that the issuance of the proposed IHA
qualifies to be categorically excluded from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
[[Page 17539]]
Summary of Request
On October 7, 2022, NMFS received a request from NFE for an IHA to
take marine mammals incidental to pile driving associated with
construction off the southeast coast of Grand Isle, Louisiana.
Following NMFS' review of the application, NFE submitted a revised
version on February 3, 2023, which was deemed adequate and complete.
NFE's request is for take of bottlenose dolphin (Tursiops truncatus) by
Level B harassment only. Neither NFE nor NMFS expect serious injury or
mortality to result from this activity and, therefore, an IHA is
appropriate.
Description of Proposed Activity
Overview
NFE proposes to construct the Louisiana FLNG Project, a deepwater
port export terminal in West Delta Lease Block 38 approximately 12
nautical miles (nm; 22 kilometers (km)) off the southeast coast of
Grand Isle, Louisiana, in approx. 26-28 meters (m; 85-91 feet (ft)) of
water (Figure 1). NFE intends to use impact pile driving to install 26
steel piles, each 108 inch (in; 2.743 m) in diameter, to support three
fixed-jacket platforms. Impact pile driving activities would occur for
a total of 9 days (three days per platform) anytime from May through
August 2023. NFE has requested authorization to incidentally take one
species (two stocks) of marine mammal by Level B harassment only. Take
would potentially result from exposure to sounds produced by impact
pile driving and is expected to produce short-term and localized
impacts in the form of behavioral harassment of marine mammals located
in the project area. No injury or mortality is expected and none is
proposed to be authorized.
NFE also plans the following: trench for pipeline laterals;
construct and install two pipeline laterals (24 in, 20 in diameter) and
tie-ins to an existing offshore natural gas pipeline; setting of three
self-elevating platforms; and anchoring for a floating liquefied
natural gas storage unit (FSU) and service vessel buoys. No take of
marine mammals is anticipated to occur incidental to all other portions
of the project (pipelines, self-elevating platform installation,
anchoring for FSU construction activities), and these activities will
not be discussed further.
Dates and Duration
This IHA would be effective from May 1, 2023 until April 30, 2024.
Impact pile driving activities would occur for a total of 9 days from
May-August 2023. NFE plans to conduct impact pile driving during
daylight hours, with pile installation beginning no earlier than one
hour after (civil) sunrise and no later than 90 minutes (min) before
(civil) sunset.
Specific Geographic Region
The project will be located within the Gulf of Mexico (GOM),
approx. 12 nm (22 km) off the southeast coast of Grand Isle, Louisiana,
at a depth of 26-28 m (85-91 ft; Figure 1). All project activities for
which take is being requested will be located in Outer Continental
Shelf West Delta Lease Block 38. For the immediate project area, the
sea floor is expected to be predominantly clay with sediment layers as
follows: clay (0-19 m), clay-silt (19-54 m), and sand (54 m).
BILLING CODE 3510-22-P
[[Page 17540]]
[GRAPHIC] [TIFF OMITTED] TN23MR23.003
BILLING CODE 3510-22-C
Detailed Description of the Specified Activity
Impact pile driving of 26 steel piles, each 108 in (2.743 m) in
diameter, to support three fixed-jacket platforms (P4, P5, P6) would
occur over 9 days (3 days per platform). Piles would be driven
sequentially and the number of piles driven per day would vary between
the
[[Page 17541]]
three platforms (Tables 1, 2). Hammer blows per day are based on
daylight-only operations with a single hammer, spread evenly across the
construction window. 9 days of active pile driving are estimated to
drive all 26 piles. Estimated hammer blows vary from 3,942 to 7,144 per
day depending on platform and pile segment being driven (piles in P5
and P6 are assembled from three separate segments).
Table 1--Pile Driving Specifications for the Three Fixed-Jacket Platforms
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Depth of Estimated Estimated
Platform Number of Length of Diameter of penetration hammer blows hammer blows
piles pile (feet) pile (inches) (feet) (total) (per pile)
--------------------------------------------------------------------------------------------------------------------------------------------------------
P4...................................................... 12 385 108 260 17,052 1,421
P5...................................................... 8 405 108 280 19,136 2,392
P6...................................................... 6 345 108 220 14,352 2,392
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Note: Hammer blows per pile vary with length of pile and depth of penetration.
Table 2--Pile Driving Progression Summary
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Total number
Platform Pile segment Hammer energy Hammer energy Duration Blows per Total number of blows per
(percent) (kilojoules) (minutes) \2\ minute of blows \1\ day
--------------------------------------------------------------------------------------------------------------------------------------------------------
P4........................... P1....................... 20 460 36.53 30 1,096 5,684
P4........................... P1....................... 40 920 42.93 30 1,288 5,684
P4........................... P1....................... 60 1,380 110.0 30 3,300 5,684
P5........................... Day 1: P1................ 20 460 85.6 30 2,568 5,256
P5........................... Day 1: P1................ 40 920 89.6 30 2,688 5,256
P5........................... Day 2: P1+P2............. 20 460 17.07 30 512 6,736
P5........................... Day 2: P1+P2............. 40 920 22.67 30 680 6,736
P5........................... Day 2: P1+P2............. 60 1,380 184.8 30 5,544 6,736
P5........................... Day 3: P1+P2+P3.......... 20 460 52.8 30 1,584 7,144
P5........................... Day 3: P1+P2+P3.......... 40 920 22.4 30 672 7,144
P5........................... Day 3: P1+P2+P3.......... 60 1,380 162.93 30 4,888 7,144
P6........................... Day 1: P1................ 20 460 64.2 30 1,926 3,942
P6........................... Day 1: P1................ 40 920 6.2 30 2,016 3,942
P6........................... Day 2: P1+P2............. 20 460 12.8 30 384 5,052
P6........................... Day 2: P1+P2............. 40 920 17 30 510 5,052
P6........................... Day 2: P1+P2............. 60 1,380 138.6 30 4,158 5,052
P6........................... Day 3: P1+P2+P3.......... 20 460 39.6 30 1,188 5,358
P6........................... Day 3: P1+P2+P3.......... 40 920 16.8 30 504 5,358
P6........................... Day 3: P1+P2+P3.......... 60 1,380 122.2 30 3,666 5,358
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Total number of blows are based on the total number of piles installed per day.
\2\ Duration provided for all piles within a 24-hour period.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, incorporated here by reference, instead of
reprinting the information. Additional information regarding population
trends and threats may be found in NMFS' Stock Assessment Reports
(SARs; <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">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 3 lists all stocks for which take is expected and proposed to
be authorized for this activity, and summarizes information related to
the population or stock, including regulatory status under the MMPA and
Endangered Species Act (ESA) and potential biological removal (PBR),
where known. PBR is defined by the MMPA as the maximum number of
animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its
optimum sustainable population (as described in NMFS' SARs). While no
serious injury or mortality is anticipated or proposed to be authorized
here, PBR and annual serious injury and mortality from anthropogenic
sources are included here as gross indicators of the status of the
species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Atlantic and GOM SARs. All values presented in Table 3 are
the most recent available at the time of publication (including from
the draft 2022 SARs) and are available online at:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
[[Page 17542]]
Table 3--Species and Stocks Likely Impacted by the Specified Activities \1\
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ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/SI
\2\ abundance survey) \3\ \4\
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Odontoceti (toothed whales,
dolphins, and porpoises).
Family Delphinidae.................
Bottlenose dolphin................. Tursiops truncatus.... Gulf of Mexico, -/-; N 0.11; 57,917; 2017- 556 65
Continental Shelf. 2018.
Bottlenose dolphin................. Tursiops truncatus.... Gulf of Mexico, -/-; N 0.13; 18,585; 2017- 167 36
Western Coastal. 2018.
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\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>; Committee on Taxonomy (2022)).
\2\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports 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> assessments. 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, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
As indicated above, one species (two managed stocks) in Table 3
temporally and spatially co-occur with the activity to the degree that
take is reasonably likely to occur. All species that could potentially
occur in the proposed project area are included in Table 3 of the IHA
application. While Atlantic spotted dolphin (Stenella frontalis),
bottlenose dolphin (northern GOM Oceanic Stock), pantropical spotted
dolphin (Stenella attenuata), Rice's whale (Balaenoptera ricei),
Risso's dolphin (Grampus griseus), and sperm whale (Physeter
microcephalus) have been documented in the region (see application
Section 6--Table 6-8), the temporal and/or spatial occurrence of these
species is such that take is not expected to occur, and they are not
discussed further beyond the explanation provided here.
Bottlenose Dolphin
Bottlenose dolphins are present year-round in the nearshore waters
of the GOM and are expected to have a common occurrence within the
vicinity of the project area. There are two distinct bottlenose dolphin
morphotypes: migratory coastal and offshore, and the population of
bottlenose dolphins in the GOM consists of a complex mosaic of 38
stocks of bottlenose dolphin (Waring et al., 2010). This includes 33
bay, sound, and estuary stocks in the inshore waters; three coastal
stocks (western, northern, eastern); the northern GOM Continental Shelf
Stock; and the northern GOM Oceanic Stock (Waring et al., 2013). Of
those, only two stocks are reasonably expected near the project area:
the GOM Western Coastal Stock and the northern GOM Continental Shelf
Stock. The northern GOM Oceanic Stock is not likely to occur within the
project area because the stock range is defined as extending from the
200-m isobath of the GOM south toward the seaward extent of the
Exclusive Economic Zone (Hayes et al., 2022) and, therefore, is not
discussed further.
Bottlenose dolphins under the GOM Western Coastal Stock have the
possibility to occur within the vicinity of the project area as this
stock range is defined as the Mississippi River Delta to the U.S.-
Mexico border, in waters typically less than 20 m (66 ft) deep along
the inner continental shelf (within 7.5 km (4.6 miles) of shore; Hayes
et al., 2022). Bottlenose dolphins under the northern GOM Continental
Shelf Stock are likely to occur within the project area as well, as
this stock inhabits waters from 20-200 m (66-656 ft) deep throughout
the U.S. GOM. There are two biologically important areas for bottlenose
dolphins north of the project area in Caminada Bay and Barataria Bay,
Louisiana, but neither project staging nor implementation are expected
to impact these areas.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approx. 65 dB
threshold from the normalized composite audiograms, with the exception
for lower limits for low-frequency cetaceans where the lower bound was
deemed to be biologically implausible and the lower bound from Southall
et al. (2007) retained. Marine mammal hearing groups and their
associated hearing ranges are provided in Table 4.
Table 4--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans 7 Hz to 35 kHz.
(baleen whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales,
beaked whales, bottlenose
whales).
[[Page 17543]]
High-frequency (HF) cetaceans 275 Hz to 160 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) 50 Hz to 86 kHz.
(underwater) (true seals).
Otariid pinnipeds (OW) 60 Hz to 39 kHz.
(underwater) (sea lions and
fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take section later in this document includes a
quantitative analysis of the number of individuals that are expected to
be taken by this activity. The Negligible Impact Analysis and
Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and whether those
impacts are reasonably expected to, or reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.
Acoustic effects on marine mammals during the specified activities
can occur from impact pile driving. The effects of underwater noise
from the NFE's proposed activities have the potential to result in
Level A or Level B harassment of marine mammals in the action area.
For general information on sound, its interaction with the marine
environment, and a description of acoustic terminology, please see,
e.g., ANSI (1986, 1995), Au and Hastings (2008), Hastings and Popper
(2005), Mitson (1995), NIOSH (1998), Richardson et al. (1995), Southall
et al. (2007), and Urick (1983). Underwater sound from active acoustic
sources can cause one or more of the following: temporary or permanent
hearing impairment, behavioral disturbance, masking, stress, and non-
auditory physical effects. The degree of effect is intrinsically
related to the signal characteristics, received level, distance from
the source, and duration of the sound exposure.
Threshold Shifts
Marine mammals exposed to high-intensity sound, or to lower-
intensity sound for prolonged periods, can experience hearing threshold
shift (TS), which is the loss of hearing sensitivity at certain
frequency ranges (Finneran, 2015). TS can be permanent (PTS; permanent
threshold shift), in which case the loss of hearing sensitivity is not
fully recoverable, or temporary (TTS; temporary threshold shift), in
which case the animal's hearing threshold would recover over time
(Southall et al., 2007).
When PTS occurs, there is physical damage to the sound receptors in
the ear (i.e., tissue damage), whereas TTS represents primarily tissue
fatigue and is reversible (Southall et al., 2007). In addition, other
investigators have suggested that TTS is within the normal bounds of
physiological variability and tolerance and does not represent physical
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to
constitute auditory injury. Behavioral disturbance to marine mammals
from sound may include a variety of effects, including subtle changes
in behavior (e.g., minor or brief avoidance of an area or changes in
vocalizations), more conspicuous changes in similar behavioral
activities, and more sustained and/or potentially severe reactions,
such as displacement from or abandonment of high-quality habitat.
Behavioral responses to sound are highly variable and context-specific
and any reactions depend on numerous intrinsic and extrinsic factors
(e.g., species, state of maturity, experience, current activity,
reproductive state, auditory sensitivity, time of day), as well as the
interplay between factors. Available studies show wide variation in
response to underwater sound; therefore, it is difficult to predict
specifically how any given sound in a particular instance might affect
marine mammals perceiving the signal.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor
porpoise (Phocoena phocena), and Yangtze finless porpoise (Neophocoena
asiaeorientalis)), and five species of pinnipeds exposed to a limited
number of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran, 2015). At low frequencies, onset-TTS
exposure levels are higher compared to those in the region of best
sensitivity (i.e., a low frequency noise would need to be louder to
cause TTS onset when TTS exposure level is higher), as shown for harbor
porpoises and harbor seals (Phoca vitulina; Kastelein et al., 2019a,
2019b, 2020a, 2020b). In addition, TTS can accumulate across multiple
exposures, but the resulting TTS would be less than the TTS from a
single, continuous exposure with the same SEL (Finneran et al., 2010;
Kastelein et al., 2014; Kastelein et al., 2015; Mooney et al., 2009).
This means that TTS predictions based on the total, cumulative SEL
would overestimate the amount of TTS from intermittent exposures such
as sonars and impulsive sources.
The potential for TTS from impact pile driving exists. After
exposure to playbacks of impact pile driving sounds (rate 2,760
strikes/hr) in captivity, mean TTS increased from 0 dB after 15 min
exposure to 5 dB after 360 min exposure; recovery occurred within 60
min (Kastelein et al., 2016). Additionally, the existing marine mammal
TTS data come from a limited number of individuals within these
species. No data are available on noise-induced hearing loss for
mysticetes. Nonetheless, what we considered herein is the best
available science. For summaries of data on TTS in marine mammals or
for further discussion of TTS onset thresholds, please see Southall et
al. (2007, 2019) and
[[Page 17544]]
Finneran (2015), and Table 5 in NMFS (2018).
In-water construction activities associated with this project would
include impact pile driving to install 26 steel piles over 9 days. The
sounds produced by this activity are considered impulsive and
intermittent. Impulsive sounds are typically transient, brief (less
than 1 second), broadband, and consist of high peak sound pressure with
rapid rise time and rapid decay (ANSI, 1986; NIOSH, 1998; NMFS, 2018).
There would likely be pauses in activities producing the sound during
each day. Given these pauses and the fact that many marine mammals are
likely moving through the project area and not remaining for extended
periods of time, the potential for TS declines.
Behavioral Harassment
Exposure to noise from pile driving also has the potential to
behaviorally disturb marine mammals. Available studies show wide
variation in response to underwater sound; therefore, it is difficult
to predict specifically how any given sound in a particular instance
might affect marine mammals perceiving the signal. If a marine mammal
does react briefly to an underwater sound by changing its behavior or
moving a small distance, the impacts of the change are unlikely to be
significant to the individual, let alone the stock or population.
However, if a sound source displaces marine mammals from an important
feeding or breeding area for a prolonged period, impacts on individuals
and populations could be significant (e.g., Lusseau and Bejder, 2007;
Weilgart, 2007; NRC, 2005).
Disturbance may result in changing durations of surfacing and
dives, number of blows per surfacing, or moving direction and/or speed;
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior (such as tail/fluke slapping or jaw
clapping); or avoidance of areas where sound sources are located.
Behavioral responses to sound are highly variable and context-specific
and any reactions depend on numerous intrinsic and extrinsic factors
(e.g., species, state of maturity, experience, current activity,
reproductive state, auditory sensitivity, time of day), as well as the
interplay between factors (e.g., Richardson et al., 1995; Wartzok et
al., 2004; Southall et al., 2007; Weilgart, 2007; Archer et al., 2010;
Southall et al., 2021). Behavioral reactions can vary not only among
individuals but also within an individual, depending on previous
experience with a sound source, context, and numerous other factors
(Ellison et al., 2012), and can vary depending on characteristics
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). Please see
Appendices B and C of Southall et al. (2007) as well as Nowacek et al.
(2007); Ellison et al. (2012), and Gomez et al. (2016) for a review of
studies involving marine mammal behavioral responses to sound.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets, sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 2007;
Melc[oacute]n et al., 2012). In addition, behavioral state of the
animal plays a role in the type and severity of a behavioral response,
such as disruption to foraging (e.g., Sivle et al., 2016; Wensveen et
al., 2017). A determination of whether foraging disruptions incur
fitness consequences would require information on or estimates of the
energetic requirements of the affected individuals and the relationship
between prey availability, foraging effort and success, and the life
history stage of the animal (Goldbogen et al., 2013).
The likely or possible impacts of NFE's proposed activities on
marine mammals could be generated from both non-acoustic and acoustic
stressors. Potential non-acoustic stressors include the physical
presence of the equipment and vessels; however, we expect that any
animals that approach the project site close enough to be harassed due
to the presence of equipment would be within the Level B harassment
zones for pile driving and would already be subject to harassment from
the in-water activities. Therefore, any impacts to marine mammals are
expected to be primarily acoustic and generated by heavy equipment
operation during pile installation (i.e., impact driving). Impact
hammers would be used to complete in-water construction and may act as
an acoustic stressor. Impact hammers operate by repeatedly dropping
and/or pushing a heavy piston onto a pile to drive the pile into the
substrate. Sound emitted by impact pile driving would be temporary and
localized. Due to the relatively limited area of impact compared to the
extensive available surrounding habitat, potential impacts from sound
are anticipated to be negligible on marine mammal habitat.
Marine Mammal Habitat Effects
NFE's proposed construction activities could have localized,
temporary impacts on marine mammal habitat, including prey, by
increasing in-water sound pressure levels and slightly decreasing water
quality. Increased noise levels may affect acoustic habitat and
adversely affect marine mammal prey in the vicinity of the project area
(see discussion below). During impact pile driving, elevated levels of
underwater noise would ensonify the project area where both fishes and
mammals occur, and could affect foraging success. Additionally, marine
mammals may avoid the area during construction, however, displacement
due to noise is expected to be temporary and is not expected to result
in long-term effects to the individuals or populations. Construction
activities are expected to be of short duration (9 days total) and
would likely have temporary impacts on marine mammal habitat through
increases in underwater sound.
In-Water Construction Effects on Potential Foraging Habitat
A temporary and localized increase in turbidity near the seafloor
would occur in the immediate area surrounding the location where piles
are installed. In general, turbidity associated with pile installation
is localized to an approx. 25-ft (7.6-m) radius around the pile
(Everitt et al., 1980). Cetaceans are not expected to be close enough
to the pile driving areas to experience effects of turbidity. Such
impact-producing factors may provoke mobile prey species to leave the
area of activity and/or cause injury or mortality in less mobile
species. This may indirectly inhibit marine mammal foraging activities
within the project area. Project impacts to marine mammal prey species
are expected to be minor and limited to short-term changes that may
result in potential prey avoidance of the project area during
construction. Marine mammals and prey species impacted by impact pile
driving activities are expected to return to normal behavior shortly
after the conclusion of pile driving operations, and return to areas of
available habitat immediate proximity to the area around the impact
pile driving activities; therefore, impacts to habitat are considered
negligible and not discussed further.
[[Page 17545]]
The area likely impacted by impact pile driving (0.2 acres) for
this project (441.5 acres) is relatively small compared to the total
available habitat in the waters off Louisiana in the northern GOM. The
proposed project area is highly influenced by anthropogenic activities,
and provides limited foraging habitat for marine mammals. Furthermore,
pile driving at the proposed project site would not obstruct long-term
movements or migration of marine mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. The
duration of fish and marine mammal avoidance of this area after pile
driving stops is unknown, but a return to normal recruitment,
distribution, and behavior is anticipated. Any behavioral avoidance by
prey of the disturbed area would still leave significantly large areas
of potential foraging habitat in the nearby vicinity.
In-Water Construction Effects on Potential Prey
Sound may affect marine mammals through impacts on the abundance,
behavior, or distribution of prey species (e.g., crustaceans,
cephalopods, fish, zooplankton, other marine mammals). Marine mammal
prey varies by species, season, and location. Here, we describe studies
regarding the effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay,
2009). Depending on their hearing anatomy and peripheral sensory
structures, which vary among species, fishes hear sounds using pressure
and particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds (e.g., impulsive) can cause overt or subtle changes in fish
behavior and local distribution. The reaction of fish to noise depends
on the physiological state of the fish, past exposures, motivation
(e.g., feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish; several are based on
studies in support of large, multiyear bridge construction projects
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Many
studies have demonstrated that impulsive sounds might affect the
distribution and behavior of some fishes, potentially impacting
foraging opportunities or increasing energetic costs (e.g., Fewtrell
and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992;
Santulli et al., 1999; Paxton et al., 2017). However, some studies have
shown no or slight reaction to impulse sounds (e.g., Pena et al., 2013;
Wardle et al., 2001; Jorgenson and Gyselman, 2009; Popper et al.,
2005).
Sound pressure levels (SPLs) of sufficient strength have been known
to cause injury to fish and fish mortality. However, in most fish
species, hair cells in the ear continuously regenerate and loss of
auditory function likely is restored when damaged cells are replaced
with new cells. Halvorsen et al. (2012a) showed that a TTS of 4-6 dB
was recoverable within 24 hr for one species. Impacts would be most
severe when the individual fish is close to the source and when the
duration of exposure is long. Injury caused by barotrauma can range
from slight to severe and can cause death, and is most likely for fish
with swim bladders. Barotrauma injuries have been documented during
controlled exposure to impact pile driving (Halvorsen et al., 2012b;
Casper et al., 2013).
The most likely impact to fishes from pile driving activities at
the project area would be temporary behavioral avoidance of the area.
In general, impacts to marine mammal prey species are expected to be
minor and temporary. Further, it is anticipated that preparation
activities for pile driving and upon initial startup of equipment would
cause fish to move away from the affected area where injuries may
occur. Therefore, relatively small portions of the proposed project
area would be affected for short periods of time and the potential for
effects on fish to occur would be temporary and limited to the duration
of sound[hyphen]generating activities (i.e., impact pile driving).
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed actions
are not likely to have a permanent, adverse effect on any fish habitat
or populations of fish species. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large areas for fish and
marine mammal foraging in the nearby vicinity. Thus, we conclude that
impacts of the specified activities are not likely to have more than
short-term adverse effects on any prey habitat or populations of prey
species. Further, any impacts to marine mammal habitat are not expected
to result in significant or long-term consequences for individual
marine mammals, or to contribute to adverse impacts on their
populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Authorized takes would be by Level B harassment only, in
the form of disruption of behavioral patterns for individual marine
mammals resulting from exposure to the acoustic source (i.e., impact
pile driving). Based on the nature of the activity and the anticipated
effectiveness of the mitigation measures (i.e., single big bubble
curtain, visual monitoring, ramp-up, power down, shutdown) discussed in
detail below in the Proposed Mitigation section, Level A harassment is
neither anticipated nor proposed to be authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
[[Page 17546]]
size). Below, we describe the factors considered here in more detail
and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 microPascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
NFE's proposed activity includes the use of an impulsive (i.e.,
impact pile driving) source and, therefore, the RMS SPL thresholds of
160 dB re 1 [mu]Pa is applicable.
Level A Harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS, 2018)
identifies dual criteria to assess auditory injury (Level A harassment)
to five different marine mammal groups (based on hearing sensitivity)
as a result of exposure to noise from two different types of sources
(impulsive or non-impulsive). NFE's proposed activity includes the use
of an impulsive (i.e., impact pile driving) source.
These thresholds are provided in Table 5. The references, analysis,
and methodology used in the development of the thresholds are described
in NMFS' 2018 Technical Guidance, which may be accessed at:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
Table 5--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat; 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including empirical sound source levels, and
underwater sound propagation modeling.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected by sound generated by the
primary component of the project (i.e., impact pile driving).
Empirical sound source modeling was developed by Tetra Tech, Inc.,
based on literature, engineering guidelines, and underwater source
measurements and acoustic modeling assessments of similar equipment and
activities. These data were then used in propagation modeling completed
by NFE. The empirical model calculation methodology is described in
detail (see Appendix C in the Underwater Acoustic Assessment of the
application) for impact piling, and that methodology was used to
determine the L<INF>pk</INF> and SEL sound source levels for the impact
piling activities. A summary of construction scenarios included in the
acoustic modeling analysis is provided in Table 5-1 of the Underwater
Acoustic Assessment of the application.
Underwater sound propagation modeling was completed by NFE using
dBSea (Marshall Day Acoustics) for the prediction of underwater noise
using bathymetry data and ``placing'' noise sources (i.e., platform
pile driving
[[Page 17547]]
location) in the modeled environment (see the Underwater Acoustic
Assessment in the application). The scenarios modeled were ones where
potential underwater noise impacts of impact pile driving on marine
species were assessed, and noise mitigation methods were also included.
To examine results in more detail, levels may be plotted in cross
sections, or a detailed spectrum may be extracted at any point in the
calculation area. Levels were calculated in third octave bands from
12.5 hertz (Hz) to 20 kilohertz (kHz). The accuracy of underwater sound
propagation modeling results is largely dependent on the sound source
characteristics and the accuracy of data inputs and assumptions used to
describe the medium between the path and receiver. The representative
acoustic modeling scenarios were derived from descriptions of the
expected construction activities and operational conditions through
consultations between the project design and engineering teams from
NFE.
The impact pile driving scenarios were modeled using a vertical
array of point sources spaced at 1 m intervals, distributing the sound
emissions from pile driving throughout the water column. The vertical
array was assigned third-octave band sound characteristics adjusted for
site-specific parameters, including expected hammer energy and number
of blows. Third octave band center frequencies from 12.5 Hz up to 20
kHz were used in the modeling. The scenarios modeled were impact pile
driving for a fixed-jacket design associated with the three fixed-
jacket platforms (P4, P5, P6; Table 6). To be conservative, it was
assumed the maximum rated hammer energy of 1,380 kJ would be employed
for all of the impact piling scenarios.
The underwater acoustic modeling analysis used a split solver, with
dBSeaPE (Parabolic Equation Method) evaluating the low frequency (12.5-
800 Hz) range and dBSeaRay (Ray Tracing Method) addressing the high
frequency (1-20 kHz) range. The dBSeaPE solver uses the range-dependent
acoustic model parabolic equation method, a versatile and robust method
of marching the sound field out in range from the sound source. This
method is widely used in the underwater acoustics community. The
dBSeaRay solver forms a solution by tracing rays from the source to the
receiver. Many rays leave the source covering a range of angles, and
the sound level at each point in the receiving field is calculated by
coherently summing the components from each ray. This is currently the
only computationally efficient method at high frequencies.
Table 6--Underwater Acoustic Modeling Scenarios--Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sound source
Duration of Total hammer Sound source level Sound source
pile blows (based Location (UTM level (peak (cumulative level (root
Platform Activity description installation on total piles coordinates) for sound sound exposure mean square
(minutes) per day) modeling locations pressure) over 24-hour sound
period) pressure)
--------------------------------------------------------------------------------------------------------------------------------------------------------
P4................... 4 piles per day (12 190 5,684 223,049 m, 3,219,466 m. 236 210 220
piles total).
P5................... 8 pile segments per day 238 7,144 222,890 m, 3,219,450 m. 236 210 220
(8 piles total).
P6................... 6 pile segments per day 122 5,358 223,176 m, 3,219,585 m. 236 210 220
(6 piles total).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: All piles are 108 in (2.743 m) diameter piles. Maximum hammer energy is 1,380 kJ.
To calculate distances to the Level A harassment and Level B
harassment thresholds for the methods and piles being used in this
project, a maximum received level-over-depth approach was used by NFE.
This approach uses the maximum received level that occurs within the
water column at each sampling point. Both the maximum range at which
the sound level was calculated in the model (R<INF>max</INF>) and the
maximum range at which a sound level was calculated excluding five
percent of the R<INF>max</INF> (R<INF>95</INF><not-eq>) were calculated
for each of the regulatory thresholds. The R<INF>95</INF><not-eq>
excludes major outliers or protruding areas associated with the
underwater acoustic modeling environment. Regardless of shape of the
calculated isopleths, the predicted range encompasses at least 95
percent of the area that would be exposed to sound at or above the
specified level. All distances to injury thresholds are presented in
terms of the R<INF>95</INF><not-eq> range. The calculated values for
all three platforms were comparable (Tables 7, 8, 9), which is expected
given the similar water depths, benthic conditions, bathymetry, and
sound speed profile influences resulting from the sites' close
proximity to one another.
For purposes of calculating and requesting take, NFE used the 6 dB
attenuated isopleths associated with the use of a single big bubble
curtain with a minimum airflow rate of 0.3 m\3\/min*m (see Proposed
Mitigation). A single bubble curtain with an airflow rate of 0.3 m\3\/
min*m can achieve 8-14 dB reduction when deployed on the seafloor at a
depth of 30 m (98 ft; Koschinski and Ludemann, 2020). Available single
big bubble curtains, operating with an airflow rate of 0.5 m\3\/min*m,
are documented to achieve a minimum of 10 dB reduction in sound
propagation (Bellmann et al., 2020). To be conservative in
determination of take estimations, a 6 dB mitigation level was chosen.
Table 7--Marine Mammal Injury and Behavioral Onset Criteria Threshold Distances (Meters) for Pile Driving at P4
Location
----------------------------------------------------------------------------------------------------------------
Distance (m) Distance (m)
Hearing group Metric Threshold (dB) without with 6 dB
attenuation attenuation
----------------------------------------------------------------------------------------------------------------
LF cetaceans.......................... Cumulative sound 183 3,929 2,010
exposure over 24-hour
period LE,24hr.
LF cetaceans.......................... Peak sound pressure 219 39 23
Lp,pk.
MF cetaceans.......................... Cumulative sound 185 116 46
exposure over 24-hour
period LE,24hr.
[[Page 17548]]
MF cetaceans.......................... Peak sound pressure 230 11 NA *
Lp,pk.
Marine mammal behavior................ Root mean square sound 160 3,208 1,560
pressure Lp.
----------------------------------------------------------------------------------------------------------------
* The threshold level is greater than the source level, therefore, distances are not generated.
Table 8--Marine Mammal Injury and Behavioral Onset Criteria Threshold Distances (Meters) for Pile Driving at P5
Location
----------------------------------------------------------------------------------------------------------------
Distance (m) Distance (m)
Hearing group Metric Threshold (dB) without with 6 dB
attenuation attenuation
----------------------------------------------------------------------------------------------------------------
LF cetaceans.......................... Cumulative sound 183 4,558 2,249
exposure over 24-hour
period LE,24hr.
LF cetaceans.......................... Peak sound pressure 219 39 24
Lp,pk.
MF cetaceans.......................... Cumulative sound 185 132 70
exposure over 24-hour
period LE,24hr.
MF cetaceans.......................... Peak sound pressure 230 12 NA *
Lp,pk.
Marine mammal behavior................ Root mean square sound 160 3,037 1,582
pressure Lp.
----------------------------------------------------------------------------------------------------------------
* The threshold level is greater than the source level, therefore, distances are not generated.
Table 9--Marine Mammal Injury and Behavioral Onset Criteria Threshold Distances (Meters) for Pile Driving at P6
Location
----------------------------------------------------------------------------------------------------------------
Distance (m) Distance (m)
Hearing group Metric Threshold (dB) without with 6 dB
attenuation attenuation
----------------------------------------------------------------------------------------------------------------
LF cetaceans.......................... Cumulative sound 183 3,908 1,887
exposure over 24-hour
period LE,24hr.
LF cetaceans.......................... Peak sound pressure 219 39 24
Lp,pk.
MF cetaceans.......................... Cumulative sound 185 111 45
exposure over 24-hour
period LE,24hr.
MF cetaceans.......................... Peak sound pressure 230 11 NA *
Lp,pk.
Marine mammal behavior................ Root mean square sound 160 3,141 1,603
pressure Lp.
----------------------------------------------------------------------------------------------------------------
* The threshold level is greater than the source level, therefore, distances are not generated.
Marine Mammal Occurrence
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information that
will inform the take calculations.
As discussed previously, given the project location in relatively
shallow shelf waters in the western GOM and brief project duration,
take is expected for only the bottlenose dolphin. However, NFE provided
quantitative analysis for additional species that rarely occur in shelf
waters and/or ESA-listed species (Rice's whales and sperm whales).
These analyses, shown in Table 10, confirmed that no take is reasonably
expected to occur for species other than bottlenose dolphin.
Marine mammal density estimates are based on the most recent marine
mammal species distribution data for the GOM (Litz et al., 2022). While
there are multiple sources of information in this region (e.g., Roberts
et al., 2016; Hayes et al., 2022; Maze-Foley and Mullin, 2006)), the
most recent information (Litz et al., 2022) was used in take estimation
calculations.
Take Estimation
Here we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization.
Potential take calculations were based on annual species density
within the project area, given the dates during which impact pile
driving would occur (May-August). Bottlenose dolphins are the only
marine mammal species with calculated take, and is the only marine
mammal species for which authorization of take is proposed. No take by
Level A harassment is anticipated during impact pile driving.
Table 10--Average Marine Mammal Densities Used in Exposure Estimates and Estimates of Calculated Takes by Level A and Level B Harassment Due to Impact
Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average
seasonal Take by Level Take by Level Take by Level Take by Level Take by Level Take by Level
Species Stock density (per A harassment B harassment A harassment B harassment A harassment B harassment
100 km \2\) at P4 at P4 at P5 at P5 at P6 at P6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic spotted dolphin.... GOM....... 0.247 0 0 0 0 0 0
Bottlenose dolphin.......... GOM....... 149.159 0 15 0 15 0 16
Pantropical spotted dolphin. GOM....... 0.000 0 0 0 0 0 0
Rice's whale................ GOM....... 0 0 0 0 0 0 0
Risso's dolphin............. GOM....... 0 0 0 0 0 0 0
Sperm whale................. GOM....... 0 0 0 0 0 0 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Cetacean density values from the NOAA Southeast Fisheries Science Center (Litz et al., 2022). Bottlenose dolphin density values not identified to
stock.
[[Page 17549]]
Bottlenose dolphin density information is not differentiated by
individual stock (Litz et al., 2022). Given the difficulty of
bottlenose dolphin identification in the field, it has been assumed
that the total calculated take of bottlenose dolphins could accrue to
either the western coastal stock or the continental shelf stock. Take
calculations presented in Table 10 indicate that bottlenose dolphins
may be present during construction activities, but do not account for
average group sizes. Average pod size is assumed to be 20 individuals
(Maze-Foley and Mullin, 2006). Due to the likelihood that bottlenose
dolphins may be present during construction activities, one pod of
bottlenose dolphins was assumed to potentially be present per each day
of impact pile driving; therefore, the total number of days (9) was
multiplied by the average group size (20) to produce the proposed take
number for authorization (Table 11).
Table 11--Average Marine Mammal Densities Used in Exposure Estimates and Estimates of Requested Takes by Level B Harassment Due to Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Take by Level Take by Level Take by Level
Species Stock B harassment B harassment B harassment Total Level B Percent
at P4 at P5 at P6 take \3\ population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bottlenose dolphin \2\ \3\................ Western Coastal............. 60 60 60 180 0.3
Bottlenose dolphin\2\ \3\................. Continental Shelf...........
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Given the difficulty of visual identification in the field for bottlenose dolphins, it has been assumed the calculated take could be accrued to
either the GOM Western Coastal stock or the northern GOM Continental Shelf stock.
\1\ Cetacean density values from Litz et al. (2022).
\2\ Bottlenose dolphin density value from Litz et al. (2022) reported for the entire GOM are presented. Estimated take is listed as the total over 3
days of activity at each platform (9 days total).
\3\ Bottlenose dolphin estimated take was adjusted to account for one group size of 20 individuals per day for 9 days of construction (Maze-Foley and
Mullin, 2006).
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned); and,
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
Single Big Bubble Curtain
NFE would employ a single big bubble curtain with a minimum airflow
rate of 0.3 m\3\/min*m. In a big bubble curtain system, the entire
construction site (installation vessel and foundation structure) is
enveloped by a nozzle hose deployed in a complete circle at a specified
distance from the site of pile driving on the sea floor. The hose is
perforated through which air is forced creating an air bubble curtain
that encloses the construction site (Bellmann et al., 2020).
Pile Driving Weather and Time Restrictions
Pile driving would commence only during daylight hours no earlier
than one hour after (civil) sunrise. Pile driving would not be
initiated later than 1.5 hr before (civil) sunset. Pile driving may
continue after dark when the installation of the same pile began during
daylight hours (1.5 hr before (civil) sunset) and must proceed for
human safety or installation feasibility reasons. Pile driving will not
be initiated in times of low visibility when the shutdown zone for MF
cetaceans (500 m) cannot be visually monitored, as determined by the
lead PSO on duty.
Protected Species Observers (PSOs)
The placement of four PSOs during all pile driving activities
(described in the Proposed Monitoring and Reporting section) would
ensure the shutdown zone is visible in good conditions. Visual
monitoring of the established zone would be performed by qualified and
NMFS-approved third-party PSOs.
Harassment and Shutdown Zones
The harassment and shutdown zones would be established and
continuously monitored by PSOs during impact pile driving to minimize
impacts to marine mammals. NMFS proposes to require the 500-m shutdown
zone. This zone is expanded from the largest estimated Level A
harassment zone (70 m) under the 6 dB reduction scenario in order to
provide a conservative monitoring area for purposes of potential
shutdown of activity (see below).
Ramp-Up Procedures
NFE would implement a ``ramp-up'' technique when impact pile
driving with the maximum hammer energy limited to 60 percent. The ramp
up technique requires an initial 30 min using a reduced hammer energy
and involves initially driving a pile using a low hammer energy and, as
the pile is driven further into the soil, the hammer energy is
increased as necessary to achieve desired soil penetration. A ramp up
would occur at the beginning of the impact pile driving of each pile
and at any time following the cessation of impact pile driving of 30
min or longer.
[[Page 17550]]
Shutdown and Power-Down Procedures
The shutdown zone around the pile driving activities would be
maintained by four PSOs, as previously described, for the presence of
marine mammals before, during, and after pile driving activity. For
pile driving, from an engineering standpoint, any significant stoppage
of driving progress may allow time for displaced sediments along the
pile surface areas to consolidate and bind. Attempts to restart the
driving of a stopped pile may be unsuccessful and create a situation
where a pile is permanently bound in a partially driven position. If a
marine mammal is observed entering or within the shutdown zone after
pile driving has commenced, a shutdown of pile driving would occur when
practicable as determined by the lead engineer on duty, who must
evaluate the following:
<bullet> Use of site-specific soil data and real-time hammer log
information to judge whether a stoppage would risk causing pile refusal
at restart of pile; and,
<bullet> Confirmation that pile penetration is deep enough to
secure pile stability in the interim situation, taking into account
weather statistics for the relevant season and the current weather
forecast.
Determination by the lead engineer on duty would be made for each
pile as the installation progresses and not for the site as a whole. If
a shutdown is called for but the lead engineer determines shutdown is
not practicable due to an imminent risk of injury or loss of life to an
individual, or risk of damage to a vessel that creates risk of injury
or loss of life for individuals, reduced hammer energy (power-down)
would be implemented when the lead engineer determines it is
practicable.
Subsequent restart/increased power of the equipment can be
initiated if the animal has been observed exiting the shutdown zone
within 30 min of the shutdown, or, after an additional time period has
elapsed with no further sighting of the animal that triggered the
shutdown (i.e., 15 min for small odontocetes, 30 min for all other
species). If pile driving shuts down for reasons other than mitigation
(e.g., mechanical difficulty) for brief periods (i.e., less than 30
min), it may be activated again without a ramp up if PSOs have
maintained constant observation and no detections of any marine mammal
have occurred within the shutdown zone.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<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.
Visual Monitoring
Monitoring and reporting requirements are provided herein. Visual
monitoring of the harassment zones, to the extent practicable, and
established shutdown zone would be performed by a minimum of four
qualified and NMFS-approved third-party PSOs. A visual observer team
comprising NMFS-approved PSOs, operating in shifts, would be stationed
aboard both the respective project vessel and a dedicated PSO vessel.
PSO qualifications would include a science degree and direct field
experience on a marine mammal observation vessel and/or aerial surveys
in the Atlantic Ocean/GOM. All PSOs would work in shifts such that no
one monitor would work more than 4 consecutive hr without a consecutive
2-hr break or longer than 12 hr during any 24-hr period.
PSOs would be responsible for visually monitoring and identifying
marine mammals approaching or entering the established harassment and
shutdown zones during survey activities. It would be the responsibility
of a designated lead PSO on duty to communicate the presence of marine
mammals as well as to communicate and enforce the action(s) that are
necessary to ensure mitigation and monitoring requirements are
implemented as appropriate. Observations from other PSOs would be
communicated to the lead PSO on duty, who would then be responsible for
implementing the necessary mitigation procedures.
PSOs would be equipped with binoculars and have the ability to
estimate distances to marine mammals located in proximity to their
established zones using range finders. Reticulated binoculars would
also be available to PSOs for use as appropriate based on conditions
and visibility to support the sighting and monitoring of marine
species.
Data on all PSO observations would be recorded based on standard
PSO collection requirements. This would include dates and locations of
survey operations; time of observation, location and weather; details
of the sightings (e.g., species, age classification (if known),
numbers, behavior), and details of any observed ``taking'' (behavioral
disturbances or injury/mortality). The data sheet would be provided to
NMFS for review and approval prior to the start of survey activities.
In addition, prior to initiation of project activities, all crew
members would undergo environmental training, a component of which
would focus on the procedures for sighting and protection of marine
[[Page 17551]]
mammals. A briefing would also be conducted between the survey
supervisors and crews, the PSOs, and NFE. The purpose of the briefing
would be to establish responsibilities of each party, define the chains
of command, discuss communication procedures, provide an overview of
monitoring purposes, and review operational procedures.
During impact pile driving, visual monitoring would occur as
follows using a minimum of four PSOs assigned to two different
locations:
<bullet> A minimum of two PSOs must be on active duty at the pile
driving vessel/platform from 60 min before, during, and for 30 min
after all pile installation activity; and,
<bullet> A minimum of two PSOs must be on active duty on a
dedicated PSO vessel from 60 min before, during, and for 30 min after
all pile installation activity. The dedicated PSO vessel must be
located at the best vantage point in order to observe and document
marine mammal sightings in proximity to the shutdown zone.
Reporting
NFE will provide the following reporting as necessary during active
pile driving activities:
<bullet> The applicant will report any observed injury or mortality
as soon as feasible and in accordance with NMFS' standard reporting
guidelines. Reports will be made by phone (305-361-4586) and by email
(<a href="/cdn-cgi/l/email-protection#7e1c121f170c50131f0d1b3e10111f1f50191108"><span class="__cf_email__" data-cfemail="d8bab4b9b1aaf6b5b9abbd98b6b7b9b9f6bfb7ae">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#98c8cab6d1ccc8b6d5f7f6f1ecf7eaf1f6ffcafde8f7eaecebd8f6f7f9f9b6fff7ee"><span class="__cf_email__" data-cfemail="9fcfcdb1d6cbcfb1d2f0f1f6ebf0edf6f1f8cdfaeff0edebecdff1f0fefeb1f8f0e9">[email protected]</span></a>) and will
include the following:
[cir] Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
[cir] Species identification (if known) or description of the
animal(s) involved;
[cir] Condition of the animal(s) (including carcass condition if
the animal is dead);
[cir] Observed behaviors of the animal(s), if alive;
[cir] If available, photographs or video footage of the animal(s);
and,
[cir] General circumstances under which the animal was discovered.
<bullet> An annual report summarizing the prior year's activities
will be provided that fully documents the methods and monitoring
protocols, summarizes the data recorded during monitoring, estimates
the number of listed marine mammals that may have been incidentally
taken during project pile driving, and provides an interpretation of
the results and effectiveness of all monitoring tasks. The annual draft
report will be provided no later than 90 days following completion of
construction activities. Any recommendations made by NMFS will be
addressed in the final report, due after the IHA expires and including
a summary of all monitoring activities, prior to acceptance by NMFS.
Final reports will follow a standardized format for PSO reporting from
activities requiring marine mammal mitigation and monitoring.
<bullet> All PSOs will use a standardized data entry format (see
Appendix B PSO Standardized Data Entry of application).
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).
Level A harassment is extremely unlikely given the required
mitigation measures designed to minimize the possibility of injury to
marine mammals. No mortality is anticipated given the nature of the
activity.
Pile installation activities have the potential to disturb or
displace marine mammals. Specifically, the project activities may
result in take, in the form of Level B harassment only, from underwater
sounds generated from impact pile installation activities. Potential
takes could occur if individuals move into the ensonified zones when
these activities are underway. The takes from Level B harassment would
be due to potential behavioral disturbance. The potential for
harassment is minimized through the implementation of planned
mitigation strategies.
Take would occur within a limited, confined area of each stock's
range. Level B harassment would be reduced to the level of least
practicable adverse impact through use of mitigation measures described
herein. Further, the amount of take authorized is extremely small when
compared to stock abundance (less than one percent for each stock).
No marine mammal stocks for which incidental take authorization is
proposed are listed as threatened or endangered under the ESA or
determined to be strategic or depleted under the MMPA. The employment
of a single big bubble curtain for sound attenuation, large shutdown
zone, and proposed monitoring make injury takes of marine mammals
unlikely. The shutdown zone would be thoroughly monitored before the
proposed pile installation begins and activities would be postponed or
hammer energy would be reduced (power down) if a marine mammal is
sighted within the shutdown zone. There is a high likelihood that
marine mammals would be detected by trained observers under
environmental conditions described for the proposed project. NFE's plan
to limit construction activities to daylight hours would also increase
detectability of marine mammals in the area. Therefore, the proposed
mitigation and monitoring measures are expected to eliminate the
potential for Level A harassment as well as reduce the amount and
intensity for Level B behavioral harassment.
Anticipated and authorized takes are expected to be limited to
short-term Level B harassment (behavioral disturbance) as construction
activities would occur over the course of 9 days. Individual animals,
even if taken multiple times, would likely move away from the sound
source and be temporarily displaced from the area due to elevated noise
level during pile removal. Marine mammals could also experience TTS if
they move into the Level B harassment zone. TTS is a temporary loss of
hearing sensitivity when exposed to loud sound, and the hearing
threshold is expected to recover completely within minutes to hours;
thus, it is not considered an injury. While TTS could occur, it is not
considered a likely outcome of this
[[Page 17552]]
activity. In all, there would be no adverse impacts to the stocks as a
whole.
The proposed project is not expected to have significant adverse
effects on marine mammal habitat. There are no Biologically Important
Areas or ESA-designated critical habitat within the project area. The
activities may cause fish to leave the area temporarily, which could
impact marine mammals' foraging opportunities in a limited portion of
the foraging range. However, due to the short duration of activities
and the relatively small area of affected habitat, the impacts to
marine mammal habitat are not expected to cause significant or long-
term negative consequences.
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 behavioral effects on individuals. The specified
activities are not expected to impact reproduction or survival of any
individual marine mammals, much less affect 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 preliminary determination that the impacts resulting from
this activity are not expected to adversely affect either of the stocks
through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> The specified activity and associated ensonified areas are
small relative to the overall habitat ranges of the stocks;
<bullet> The applicant is required to implement mitigation measures
to minimize impacts, such as a single big bubble curtain, ramp-up
procedures, and implementation of shutdown zone, when practicable;
<bullet> Biologically important areas or critical habitat have not
been identified within the project area; and,
<bullet> The lack of anticipated significant or long-term effects
to marine mammal habitat.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity would have a negligible impact
on all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
NMFS proposes to authorize incidental take by Level B harassment
only of one marine mammal species with two managed stocks. The total
amount of takes proposed for authorization relative to the best
available population abundance is below one third of the estimated
stock abundances and less than one percent for both stocks.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species.
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to NFE for conducting impact pile driving to support
construction of liquefied natural gas platforms in waters off Grand
Isle, Louisiana, from May 1, 2023, through April 30, 2024, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. A draft of the proposed IHA can be found 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>.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA. We also request
comment on the potential renewal of this proposed IHA as described in
the paragraph below. Please include with your comments any supporting
data or literature citations to help inform decisions on the request
for this IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, one-year
renewal IHA following notice to the public providing an additional 15
days for public comments when (1) up to another year of identical or
nearly identical activities as described in the Description of Proposed
Activities section of this notice is planned or (2) the activities as
described in the Description of Proposed Activities section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond one year from
expiration of the initial IHA).
<bullet> The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or
[[Page 17553]]
include changes so minor (e.g., reduction in pile size) that the
changes do not affect the previous analyses, mitigation and monitoring
requirements, or take estimates (with the exception of reducing the
type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: March 20, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2023-06006 Filed 3-22-23; 8:45 am]
BILLING CODE 3510-22-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.