[Federal Register Volume 88, Number 56 (Thursday, March 23, 2023)]
[Notices]
[Pages 17538-17553]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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 
[email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities 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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems 
accessing these documents, please call the contact listed above.

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; www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these 
species (e.g., physical and behavioral descriptions) may be found on 
NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 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: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

[[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\
--------------------------------------------------------------------------------------------------------------------------------------------------------
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.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; 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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments 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: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     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 Lpk 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 (Rmax) and the 
maximum range at which a sound level was calculated excluding five 
percent of the Rmax (R95) were calculated 
for each of the regulatory thresholds. The R95 
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 R95 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:
     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,
     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:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.

Visual Monitoring

    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:
     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,
     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:
     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 
([email protected] and [email protected]) 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.
     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.
     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:
     No serious injury or mortality is anticipated or 
authorized;
     The specified activity and associated ensonified areas are 
small relative to the overall habitat ranges of the stocks;
     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;
     Biologically important areas or critical habitat have not 
been identified within the project area; and,
     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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

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:
     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).
     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