Notice2023-21089
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Marine Geophysical Survey in Coastal Waters Off of Texas
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 27, 2023
Effective
September 29, 2023
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
In accordance with the regulations implementing the Marine Mammal Protection Act (MMPA) as amended, notification is hereby given that NMFS has issued an incidental harassment authorization (IHA) to the University of Texas at Austin (UT) to incidentally harass marine mammals during marine geophysical survey activities in coastal waters off of Texas.
Full Text
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<title>Federal Register, Volume 88 Issue 186 (Wednesday, September 27, 2023)</title>
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[Federal Register Volume 88, Number 186 (Wednesday, September 27, 2023)]
[Notices]
[Pages 66380-66392]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-21089]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XD318]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to a Marine Geophysical Survey in
Coastal Waters Off of Texas
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization.
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA) as amended, notification is hereby given
that NMFS has issued an incidental harassment authorization (IHA) to
the University of Texas at Austin (UT) to incidentally harass marine
mammals during marine geophysical survey activities in coastal waters
off of Texas.
DATES: This Authorization is effective from September 29, 2023 through
September 28, 2024.
ADDRESSES: Electronic copies of the application and supporting
documents, as well as a list of the references cited in this document,
may be obtained online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities</a>. In case of problems accessing these documents, please
call the contact listed below.
FOR FURTHER INFORMATION CONTACT: Rachel Wachtendonk, Office of
Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et
seq.) directs the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the
[[Page 66381]]
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.
Summary of Request
On March 7, 2023, NMFS received a request from UT for an IHA to
take marine mammals incidental to conducting a marine geophysical
survey in coastal waters off of Texas. Following NMFS' review of the
application, UT submitted a revised version on April 25, 2023. The
application was deemed adequate and complete on April 27, 2023. UT's
request is for take of bottlenose dolphins, Atlantic spotted dolphins,
and rough-toothed dolphin by Level B harassment only. Neither UT nor
NMFS expect serious injury or mortality to result from this activity
and, therefore, an IHA is appropriate. There are no changes from the
proposed IHA to the final IHA.
Description of the Specified Activity
Overview
UT plans to conduct a marine geophysical survey, specifically a low
energy seismic survey, in coastal waters off of Texas during a 10 day
period in the fall of 2023. The survey will take place in water depths
of less than 20 meters (m). To complete this survey the vessel will tow
one to two Generator-Injector (GI) airguns, each with a volume of 105
cubic inch (in\3\; 1,721 cubic cm (cm\3\)), for a total volume of 210
in\3\ (3,441 cm\3\).
The purpose of the planned survey is to validate novel dynamic
positioning technology for improving the accuracy in time and space of
high resolution 3-dimensional (HR3D) seismic datasets, in particular as
it pertains to field technology of offshore carbon capture systems.
Dates and Duration
The survey is planned to occur over a 10 day period during the fall
of 2023 (the exact dates are uncertain). During that time, the airguns
will operate continuously (i.e., 24-hours per day).
Specific Geographic Region
The planned survey area is 222 square kilometers (km\2\) and will
occur within the approximate area of 28.9-29.1[deg] N latitude, 94.9-
95.2[deg] W longitude in the coastal waters off of Texas. This location
is offshore San Luis Pass, which defines the southern tip of Galveston
Island, Texas. The closest point of approach of the planned survey area
to the coast is approximately 3 km. The planned survey area is depicted
in Figure 1, and the survey lines could occur anywhere within the
survey area. The water depth of the planned survey area ranges from 10
to 20 m. The survey vessel (the R/V Brooks McCall (McCall) or similar
vessel operated by TDI-Brooks International) will likely depart and
return to Freeport or Galveston, Texas.
[[Page 66382]]
[GRAPHIC] [TIFF OMITTED] TN27SE23.005
A detailed description of the planned geophysical survey was
provided in the Federal Register notice of the proposed IHA (88 FR
53453, August 8, 2023). Since that time, no changes have been made to
the planned survey activities. Therefore, a detailed description is not
provided here. Please refer to that Federal Register notice for the
description of the specified activity.
Comments and Responses
A notice of NMFS' proposal to issue an IHA to UT was published in
the Federal Register on August 8, 2023 (88 FR 53453). That notice
described, in detail, UT's activities, the marine mammal species that
may be affected by the activities, and the anticipated effects on
marine mammals. In that notice, we requested public input on the
request for authorization described therein, our analyses, the proposed
authorization, and any other aspect of the notice of proposed IHA, and
requested that interested persons submit relevant information,
suggestions, and comments. This proposed notice was available for a 30-
day public comment period. NMFS received no public comments.
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 1 lists all species or stocks for which take is expected and
authorized for this activity and summarizes information related to the
population or stock, including regulatory status under the MMPA and
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 authorized here, PBR and
annual serious injury and mortality from anthropogenic sources are
included here as gross indicators of the status of the species or
stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Atlantic and Gulf of Mexico
[[Page 66383]]
SARs. All values presented in Table 1 are the most recent available at
the time of publication and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 1--Species Likely Impacted by the Specified Activities \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gulf of
Stock abundance Mexico
ESA/ MMPA (CV, Nmin, most population
Common name Scientific name Stock status; recent abundance PBR Annual M/ abundance
strategic (Y/ survey) \3\ SI \4\ (Roberts
N) \2\ et al.
2016)
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Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Atlantic spotted dolphin.... Stenella frontalis. Gulf of Mexico..... -/-; N 21,506 (0.26; 166............... 36 47,488
17,339; 2018).
Rough-toothed dolphin....... Steno bredanensis.. Gulf of Mexico..... -/-; N unk (n/a; unk; undetermined...... 39 4,853
2018).
Bottlenose dolphin.......... Tursiops truncatus. Gulf of Mexico -/-; N 20,759 (0.13; 167............... 36 138,602
Western Coastal. 18,585; 2018).
Northern Gulf of -/-; N 63,280 (0.11; 556............... 65 138,602
Mexico Continental 57,917; 2018).
Shelf.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>; Committee on Taxonomy (2022)).
\2\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a> assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strike). Annual M/SI (mortality/serious injury) often cannot be determined precisely and is in some cases presented as a
minimum value or range.
As indicated above, all 3 species (with 4 managed stocks) in Table
1 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 planned survey areas are included in Table 2
of the IHA application. While the additional 11 species listed in Table
2 of UT's application have been infrequently sighted in the survey
area, 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. Species or stocks that only occur
in deep waters (>200 m) within the Gulf of Mexico are unlikely to be
observed during this survey where the maximum water depth is 20 m, and
thus, the following species or stocks will not be considered further:
offshore stock of bottlenose dolphins, pantropical spotted dolphin,
spinner dolphin, striped dolphin, Clymene dolphin, Fraser's dolphin,
Risso's dolphin, melon-headed whale, pygmy killer whale, false killer
whale, killer whale, and short-finned pilot whale.
A detailed description of the species likely to be affected by the
geophysical survey, including brief introductions to the species and
relevant stocks as well as available information regarding population
trends and threats, and information regarding local occurrence, were
provided in the Federal Register notice for the proposed IHA (88 FR
53453, August 8, 2023); since that time, we are not aware of any
changes in the status of these species and stocks; therefore, detailed
descriptions are not provided here. Please refer to that Federal
Register notice for these descriptions. Please also refer to NMFS'
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>) for generalized
species accounts.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65-
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 2.
Table 2--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans 7 hertz (Hz) to 35 kilohertz (kHz).
(baleen whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
[[Page 66384]]
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth 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
The effects of underwater noise from UT's survey activities have
the potential to result in behavioral harassment of marine mammals in
the vicinity of the survey area. The notice of proposed IHA (88 FR
53453, August 8, 2023) included a discussion of the effects of
anthropogenic noise on marine mammals and the potential effects of
underwater noise from UT on marine mammals and their habitat. That
information and analysis is incorporated by reference into this final
IHA determination and is not repeated here; please refer to the notice
of proposed IHA (88 FR 53453, August 8, 2023).
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
authorized through the IHA, which will inform both NMFS' consideration
of ``small numbers,'' and the negligible impact determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes will be by Level B harassment only, in the form of
disruption of behavioral patterns for individual marine mammals
resulting from exposure to sound from low energy seismic airguns. Based
on the nature of the activity, Level A harassment is neither
anticipated nor authorized. As described previously, no serious injury
or mortality is anticipated or authorized for this activity. Below we
describe how the authorized take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the 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 permanent threshold shift (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 (re 1
micropascal ([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 temporary threshold shift (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.
UT's planned survey includes the use of impulsive seismic sources
(e.g., GI-airgun) and therefore, the 160 dB re 1 [mu]Pa (rms) criterion
is applicable for analysis of Level B harassment.
[[Page 66385]]
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise from
two different types of sources (impulsive or non-impulsive). UT's
planned survey includes the use of impulsive sources.
These thresholds are provided in the Table 3 and 4 below. The
references, analysis, and methodology used in the development of the
thresholds are described in NMFS' 2018 Technical Guidance, which may be
accessed at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The planned survey will entail the use of up to two 105 in\3\
airguns with a maximum total discharge of 210 in\3\ at a tow depth of
3-4 m. Lamont-Doherty Earth Observatory (L-DEO) model results were used
to determine the 160 dB<INF>rms</INF> radius for the two-airgun array
in water depths >100 m. Received sound levels were predicted by L-DEO's
model (Diebold et al., 2010) as a function of distance from the airguns
for the two 105 in\3\ airguns with a maximum total discharge of 210
in\3\. This modeling approach uses ray tracing for the direct wave
traveling from the array to the receiver and its associated source
ghost (reflection at the air-water interface in the vicinity of the
array), in a constant-velocity half-space (infinite homogenous ocean
layer, unbounded by a seafloor).
The planned surveys will acquire data with up to two 105-in\3\ GI
guns (separated by up to 2.4 m) at a tow depth of ~3-4 m. The shallow-
water radii are obtained by scaling the empirically derived
measurements from the Gulf of Mexico calibration survey to account for
the differences in volume and tow depth between the calibration survey
(6,600 in\3\ at 6 m tow depth) and the planned survey (210 in\3\ at 4 m
tow depth). A simple scaling factor is calculated from the ratios of
the isopleths calculated by the deep-water L-DEO model, which are
essentially a measure of the energy radiated by the source array.
L-DEO's methodology is described in greater detail in UT's IHA
application. The estimated distances to the Level B harassment isopleth
for the planned airgun configuration are shown in Table 3.
Table 3--Predicted Radial Distances From the R/V Brooks McCall Seismic
Source to Isopleths Corresponding to Level B Harassment Threshold
------------------------------------------------------------------------
Predicted
distances (m) to
Airgun configuration Water depth (m) 160 dB received
sound level
------------------------------------------------------------------------
Two 105-in GI guns.............. <100 \1\ 1,750
------------------------------------------------------------------------
\1\ Distance is based on empirically derived measurements in the Gulf of
Mexico with scaling applied to account for differences in tow depth.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional user
spreadsheet tool to accompany the Technical Guidance (2018) that can be
used to relatively simply predict an isopleth distance for use in
conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. Table 4
presents the modeled PTS isopleths for mid-frequency cetaceans, the
only hearing group for which takes are expected, based on L-DEO
modeling incorporated in the companion User Spreadsheet (NMFS 2018).
Table 4--Modeled Radial Distances to Isopleths Corresponding to Level A
Harassment Thresholds
------------------------------------------------------------------------
Hearing group MF
------------------------------------------------------------------------
PTS Peak..................................................... 1.5
PTS SELcum................................................... 0
------------------------------------------------------------------------
Predicted distances to Level A harassment isopleths, which vary
based on marine mammal hearing groups, were calculated based on
modeling performed by L-DEO using the Nucleus software program and the
NMFS User Spreadsheet, described below. The acoustic thresholds for
impulsive sounds (e.g., airguns) contained in the Technical Guidance
(2018) were presented as dual metric acoustic thresholds using both
cumulative sound energy (SEL<INF>cum</INF>) and peak sound pressure
metrics (NMFS 2016a). As dual metrics, NMFS considers onset of PTS
(Level A harassment) to have occurred when either one of the two
metrics is exceeded (i.e., metric resulting in the largest isopleth).
The SEL<INF>cum</INF> metric considers both level and duration of
exposure, as well as auditory weighting functions by marine mammal
hearing group. In recognition of the fact that the requirement to
calculate Level A harassment ensonified areas could be more technically
challenging to predict due to the duration component and the use of
weighting functions in the new SEL<INF>cum</INF> thresholds, NMFS
developed an optional User Spreadsheet that includes tools to help
predict a simple isopleth that can be used in conjunction with marine
mammal density or occurrence to facilitate the estimation of take
numbers.
The SEL<INF>cum</INF> for the two-GI airgun array is derived from
calculating the modified farfield signature. The farfield signature is
often used as a theoretical representation of the source level. To
compute the farfield signature, the source level is estimated at a
large distance (right) below the array (e.g., 9 km), and this level is
back projected mathematically to a notional distance of 1 m from the
array's geometrical center. However, it has been recognized that the
source level from the theoretical farfield
[[Page 66386]]
signature is never physically achieved at the source when the source is
an array of multiple airguns separated in space (Tolstoy et al., 2009).
Near the source (at short ranges, distances <1 km), the pulses of sound
pressure from each individual airgun in the source array do not stack
constructively as they do for the theoretical farfield signature. The
pulses from the different airguns spread out in time such that the
source levels observed or modeled are the result of the summation of
pulses from a few airguns, not the full array (Tolstoy et al., 2009).
At larger distances, away from the source array center, sound pressure
of all the airguns in the array stack coherently, but not within one
time sample, resulting in smaller source levels (a few dB) than the
source level derived from the farfield signature. Because the farfield
signature does not take into account the interactions of the two
airguns that occur near the source center and is calculated as a point
source (single airgun), the modified farfield signature is a more
appropriate measure of the sound source level for large arrays. For
this smaller array, the modified farfield changes will be
correspondingly smaller as well, but this method is used for
consistency across all array sizes.
Auditory injury for all species is unlikely to occur given the
small modeled zones of injury (estimated zone less than 2 m for mid-
frequency cetaceans). Additionally, animals are expected to have
aversive/compensatory behavior in response to the activity (Nachtigall
et al., 2018) further limiting the likelihood of auditory injury for
all species. UT did not request authorization of take by Level A
harassment, and no take by Level A harassment is authorized by NMFS.
Marine Mammal Occurrence
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations.
For the planned survey area in the northwest Gulf of Mexico, UT
determined that the best source of density data for marine mammal
species that might be encountered in the project area was habitat-based
density modeling conducted by Garrison et al. (2022). The Garrison et
al. (2022) data provides abundance estimates for marine mammal species
in the Gulf of Mexico within 40 km\2\ hexagons (~3.9 km sides and ~7 km
across from each side) on a monthly basis. To calculate expected
densities specific to the survey area, UT created a 7 km perimeter
around the survey area and used that perimeter to select the density
hexagons for each species in each month. The 7 km distance was chosen
for the perimeter to ensure that at least one full density hexagon
outside the survey area in all directions was selected, providing a
more robust sample for the calculations. They then calculated the mean
of the predicted densities from the selected cells for each species and
month. The highest mean monthly density was chosen for each species
from the months of September to December (i.e., the months within which
the survey is expected to occur). NMFS concurred with this approach to
calculate species density.
Rough-toothed dolphins were not modeled by Garrison et al. (2022)
due to a lack of sightings, so habitat-based marine mammal density
estimates from Roberts et al. (2016) were used. The Roberts et al.
(2016) models consisted of 10 km x 10 km grid cells containing average
annual densities for U.S. waters in the Gulf of Mexico. The same 7 km
perimeter described above was used to select grid cells from the
Roberts et al. (2016) dataset, and the mean of the selected grid cells
for rough-toothed dolphins was calculated to estimate the annual
average density of the species in the survey area. Estimated densities
used and Level B harassment ensonified areas to inform take estimates
are presented in Table 5.
Table 5--Marine Mammal Densities and Total Ensonified Area of Activities
in the Planned Survey Area
------------------------------------------------------------------------
Estimated Level B
Species density (#/ ensonified
km\2\) area (km\2\)
------------------------------------------------------------------------
Atlantic spotted dolphin................ \b\ 0.00082 7,866
Bottlenose dolphin \a\.................. \b\ 0.34024 7,866
Rough-toothed dolphin................... \c\ 0.00362 7,866
------------------------------------------------------------------------
\a\ Bottlenose dolphin density estimate does not differentiate between
coastal and shelf stocks.
\b\ Density calculated from Garrison et al. (2022).
\c\ Density calculated from Roberts et al. (2016).
Take Estimation
Here, we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and authorized. In order to estimate the number of
marine mammals predicted to be exposed to sound levels that would
result in Level B harassment, radial distances from the airgun array to
the predicted isopleth corresponding to the Level B harassment
threshold was calculated, as described above. Those radial distances
were then used to calculate the area(s) around the airgun array
predicted to be ensonified to sound levels that exceed the harassment
thresholds. The area expected to be ensonified on 1 day was determined
by multiplying the number of line km possible in 1 day by two times the
160-dB radius plus adding endcaps to the start and beginning of the
line. The daily ensonified area was then multiplied by the number of
survey days (10 days). The highest mean monthly density for each
species was then multiplied by the total ensonified area to calculate
the estimated takes of each species.
No takes by Level A harassment are expected or authorized.
Estimated takes for the planned survey are shown in Table 6.
[[Page 66387]]
Table 6--Estimated Take for Authorization
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated take Authorized
---------------- take Stock Percent of
Species Stock ---------------- abundance \1\ stock
Level B Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic spotted dolphin....................... Gulf of Mexico......................... 6 \2\ 26 21,506 0.12
Bottlenose dolphin \3\......................... Gulf of Mexico Western Coastal......... 2,676 2,676 20,759 12.89
Northern Gulf of Mexico Continental 63,280 4.23
Shelf.
Rough-toothed dolphin.......................... Gulf of Mexico......................... 28 28 \3\ 4,853 0.58
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Stock abundance for Atlantic spotted dolphins and bottlenose dolphins was taken from Garrison et al. (2022). Stock abundance for rough-toothed
dolphins was taken from Roberts et al. (2016), as Garrison et al. (2022) did not create a model for this species.
\2\ Estimated take increased to mean group size from Maze-Foley and Mullin (2006).
\3\ Estimated take for bottlenose dolphins is not apportioned to stock, as density information does not differentiate between coastal and shelf
dolphins. However, based on the planned survey depths, we expect that most of the takes would be from the coastal stock, but some takes could be from
the shelf stock. Percent of stock was calculated as if all takes estimated for authorization accrued to the single stock with the lowest population
abundance.
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.
Mitigation measures that will be adopted during the planned survey
include, but are not limited to: (1) vessel speed or course alteration,
provided that doing so would not compromise operation safety
requirements; (2) monitoring a pre-start clearance zone; and (3) ramp-
up procedures.
Vessel-Visual Based Mitigation Monitoring
Visual monitoring requires the use of trained observers (herein
referred to as visual protected species observers (PSOs)) to scan the
ocean surface visually for the presence of marine mammals. PSOs shall
establish and monitor a pre-start clearance zone and, to the extent
practicable, a Level B harassment zone (Table 3). These zones shall be
based upon the radial distance from the edges of the acoustic source
(rather than being based on the center of the array or around the
vessel itself). During pre-start clearance (i.e., before ramp-up
begins), the pre-start clearance zone is the area in which observations
of marine mammals within the zone would prevent airgun operations from
beginning (i.e., ramp-up). The pre-start clearance zone encompasses the
area at and below the sea surface out to a radius of 200 meters from
the edges of the airgun array.
During survey operations (e.g., any day on which use of the
acoustic source is planned to occur, and whenever the acoustic source
is in the water, whether activated or not), a minimum of two PSOs must
be on duty and conducting visual observations at all times during
daylight hours (i.e., from 30 minutes prior to sunrise through 30
minutes following sunset). Visual monitoring must begin no less than 30
minutes prior to ramp-up and must continue until 1 hour after use of
the acoustic source ceases or until 30 minutes past sunset. Visual PSOs
must coordinate to ensure 360 degree visual coverage around the vessel
from the most appropriate observation posts, and must conduct visual
observations using binoculars and the naked eye while free from
distractions and in a consistent, systematic, and diligent manner.
PSOs shall establish and monitor a pre-start clearance zone and to
the extent practicable, a Level B harassment zone. These zones shall be
based upon the radial distance from the edges of the acoustic source
(rather than being based on the center of the array or around the
vessel itself).
Any observations of marine mammals by crew members shall be relayed
to the PSO team. During good conditions (e.g., daylight hours, Beaufort
sea state (BSS) three or less), visual PSOs shall conduct observations
when the acoustic source is not operating for comparison of sightings
rates and behavior with and without use of the acoustic source and
between acquisition periods, to the maximum extent practicable.
Visual PSOs may be on watch for a maximum of 4 consecutive hours
followed by a break of at least 1 hour between watches and may conduct
a maximum of 12 hours of observation per 24-hour period.
Pre-Start Clearance and Ramp-Up
Ramp-up is the gradual and systematic increase of emitted sound
levels from an acoustic source. Ramp-up will begin with one GI airgun
105 in\3\ first being activated, followed by the second after 5
minutes. The intent of pre-clearance observation (30 minutes) is to
ensure no marine mammals are observed within the pre-start clearance
zone prior to the beginning of ramp-up. The intent of ramp-up is to
warn marine mammals in the vicinity of survey activities and to allow
sufficient time for those animals to leave the immediate vicinity. A
ramp-up procedure, involving a stepwise increase in the number of
airguns are activated and the full volume is achieved, is required at
all times as part of the activation of the
[[Page 66388]]
acoustic source. All operators must adhere to the following pre-
clearance and ramp-up requirements:
(1) The operator must notify a designated PSO of the planned start
of ramp-up as agreed upon with the lead PSO; the notification time
should not be less than 60 minutes prior to the planned ramp-up in
order to allow PSOs time to monitor the pre-start clearance zone for 30
minutes prior to the initiation of ramp-up (pre-start clearance);
<bullet> Ramp-ups shall be scheduled so as to minimize the time
spent with the source activated prior to reaching the designated run-
in;
<bullet> One of the PSOs conducting pre-start clearance
observations must be notified again immediately prior to initiating
ramp-up procedures and the operator must receive confirmation from the
PSO to proceed;
<bullet> Ramp-up may not be initiated if any marine mammal is
within the pre-start clearance zone. If a marine mammal is observed
within the pre-start clearance zone during the 30 minutes pre-clearance
period, ramp-up may not begin until the animal(s) has been observed
exiting the zone or until an additional time period has elapsed with no
further sightings (15 minutes for small delphinids and 30 minutes for
all other species);
<bullet> Ramp-up must begin by activating the first airgun for 5
minutes and then adding the second airgun; and
<bullet> PSOs must monitor the pre-start clearance zone during
ramp-up, and ramp-up must cease and the source must be shut down upon
detection of a marine mammal within the pre-start clearance zone. Once
ramp-up has begun, observations of marine mammals for which take
authorization is granted within the pre-start clearance zone does not
require shutdown.
(2) If the acoustic source is shut down for brief periods (i.e.,
less than 30 minutes) for reasons other than implementation of
prescribed mitigation (e.g., mechanical difficulty), it may be
activated again without ramp-up if PSOs have maintained constant
observation and no detections of marine mammals have occurred within
the pre-start clearance zone. For any longer shutdown, pre-start
clearance observation and ramp-up are required. Ramp-up may occur at
times of poor visibility (e.g., BSS 4 or greater), including nighttime,
if appropriate visual monitoring has occurred with no detections of
marine mammals in the 30 minutes prior to beginning ramp-up. Acoustic
source activation may only occur at night where operational planning
cannot reasonably avoid such circumstances.
<bullet> Testing of the acoustic source involving all elements
requires ramp-up. Testing limited to individual source elements or
strings does not require ramp-up but does require a 30 minute pre-start
clearance period.
Shutdown Procedures
The shutdown requirement will be waived for small dolphins. As
defined here, the small dolphin group is intended to encompass those
members of the Family Delphinidae most likely to voluntarily approach
the source vessel for purposes of interacting with the vessel and/or
airgun array (e.g., bow riding). This exception to the shutdown
requirement applies solely to specific genera of small dolphins--Steno,
Stenella, and Tursiops. As Tursiops and Steno are the only species
expected to potentially be encountered, there is no shutdown
requirement included in the IHA for species for which take is
authorized.
Vessel Strike Avoidance Measures
These measures apply to all vessels associated with the planned
survey activity; however, we note that these requirements do not apply
in any case where compliance would create an imminent and serious
threat to a person or vessel or to the extent that a vessel is
restricted in its ability to maneuver and, because of the restriction,
cannot comply. These measures include the following:
(1) Vessel operators and crews must maintain a vigilant watch for
all marine mammals and slow down, stop their vessel, or alter course,
as appropriate and regardless of vessel size, to avoid striking any
marine mammal. A single marine mammal at the surface may indicate the
presence of submerged animals in the vicinity of the vessel; therefore,
precautionary measures should be exercised when an animal is observed.
A visual observer aboard the vessel must monitor a vessel strike
avoidance zone around the vessel (specific distances detailed below),
to ensure the potential for strike is minimized. Visual observers
monitoring the vessel strike avoidance zone can be either third-party
observers or crew members, but crew members responsible for these
duties must be provided sufficient training to (1) distinguish marine
mammals from other phenomena and (2) broadly to identify a marine
mammal as a baleen whale, sperm whale, or other marine mammals;
(2) Vessel speeds must be reduced to 10 knots (kn) (18.5 km/h) or
less when mother and calf pairs, pods, or large assemblages of
cetaceans are observed near a vessel;
(3) All vessels must maintain a minimum separation distance of 100
m from sperm whales;
(4) All vessels must maintain a minimum separation distance of 500
m baleen whales. If a baleen whale is sighted within the relevant
separation distance, the vessel must steer a course away at 10 kn or
less until the 500 m separation distance has been established. If a
whale is observed but cannot be confirmed as a species other than a
baleen whale, the vessel operator must assume that it is a baleen whale
and take appropriate action.
(5) All vessels must, to the maximum extent practicable, attempt to
maintain a minimum separation distance of 50 m from all other marine
mammals, with an understanding that at times this may not be possible
(e.g., for animals that approach the vessel); and
(6) When marine mammals are sighted while a vessel is underway, the
vessel should take action as necessary to avoid violating the relevant
separation distance (e.g., attempt to remain parallel to the animal's
course, avoid excessive speed or abrupt changes in direction until the
animal has left the area). This does not apply to any vessel towing
gear or any vessel that is navigationally constrained.
Based on our evaluation of the applicant's planned measures, NMFS
has determined that the mitigation measures provide the means of
effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved
[[Page 66389]]
understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
Vessel-Based Visual Monitoring
As described above, PSO observations will take place during daytime
airgun operations. Two visual PSOs will be on duty at all time during
daytime hours. Monitoring shall be conducted in accordance with the
following requirements:
(1) UT must work with the selected third-party observer provider to
ensure PSOs have all equipment (including backup equipment) needed to
adequately perform necessary tasks, including accurate determination of
distance and bearing to observed marine mammals, and to ensure that
PSOs are capable of calibrating equipment as necessary for accurate
distance estimates and species identification. See Condition 5(d) in
the IHA for list of equipment.
PSOs must have the following requirements and qualifications:
(1) PSOs shall be independent, dedicated and trained and must be
employed by a third-party observer provider;
(2) PSOs shall have no tasks other than to conduct visual
observational effort, collect data, and communicate with and instruct
relevant vessel crew with regard to the presence of protected species
and mitigation requirements (including brief alerts regarding maritime
hazards);
(3) PSOs shall have successfully completed an approved PSO training
course appropriate for their designated task (visual);
(4) NMFS must review and approve PSO resumes accompanied by a
relevant training course information packet that includes the name and
qualifications (i.e., experience, training completed, or educational
background) of the instructor(s), the course outline or syllabus, and
course reference material as well as a document stating successful
completion of the course;
(5) PSOs must successfully complete relevant training, including
completion of all required coursework and passing (80 percent or
greater) a written and/or oral examination developed for the training
program;
(6) PSOs must have successfully attained a bachelor's degree from
an accredited college or university with a major in one of the natural
sciences, a minimum of 30 semester hours or equivalent in the
biological sciences, and at least 1 undergraduate course in math or
statistics; and
(7) The educational requirements may be waived if the PSO has
acquired the relevant skills through alternate experience. Requests for
such a waiver shall be submitted to NMFS and must include written
justification. Requests shall be granted or denied (with justification)
by NMFS within one week of receipt of submitted information. Alternate
experience that may be considered includes, but is not limited to:
<bullet> Secondary education and/or experience comparable to PSO
duties;
<bullet> Previous work experience conducting academic, commercial,
or government-sponsored protected species surveys; or
<bullet> Previous work experience as a PSO; the PSO should
demonstrate good standing and consistently good performance of PSO
duties.
At least one visual PSO must be unconditionally approved (i.e.,
have a minimum of 90 days at-sea experience working in that role at the
particular Tier level (1-3) with no more than 18 months elapsed since
the conclusion of the at-sea experience). One PSO with such experience
shall be designated as the lead for the entire PSO team. The lead PSO
shall serve as primary point of contact for the vessel operator. To the
maximum extent practicable, the duty schedule shall be planned such
that unconditionally-approved PSOs are on duty with conditionally-
approved PSOs.
PSOs must use standardized electronic data collection forms. At a
minimum, the following information must be recorded:
<bullet> Vessel name, vessel size and type, maximum speed
capability of vessel;
<bullet> Dates (MM/DD/YYYY format) of departures and returns to
port with port name;
<bullet> PSO names and affiliations, PSO identification (ID;
initials or other identifier);
<bullet> Date (MM/DD/YYYY) and participants of PSO briefings;
<bullet> Visual monitoring equipment used (description);
<bullet> PSO location on vessel and height (in meters) of
observation location above water surface;
<bullet> Watch status (description);
<bullet> Dates (MM/DD/YYYY) and times (Greenwich mean time (GMT) or
coordinated universal time (UTC)) of survey on/off effort and times
(GMC/UTC) corresponding with PSO on/off effort;
<bullet> Vessel location (decimal degrees) when survey effort began
and ended and vessel location at beginning and end of visual PSO duty
shifts;
<bullet> Vessel location (decimal degrees) at 30-second intervals
if obtainable from data collection software, otherwise at practical
regular interval;
<bullet> Vessel heading (compass heading) and speed (in knots) at
beginning and end of visual PSO duty shifts and upon any change;
<bullet> Water depth (in meters) (if obtainable from data
collection software);
<bullet> Environmental conditions while on visual survey (at
beginning and end of PSO shift and whenever conditions change
significantly), including BSS and any other relevant weather conditions
including cloud cover, fog, sun glare, and overall visibility to the
horizon;
<bullet> Factors that may have contributed to impaired observations
during each PSO shift change or as needed as environmental conditions
changed (description) (e.g., vessel traffic, equipment malfunctions);
and
<bullet> Vessel/Survey activity information (and changes thereof)
(description), such as acoustic source power output while in operation,
number and volume of acoustic source operating in the array, tow depth
of the acoustic source, and any other notes of significance (i.e., pre-
start clearance, ramp-up, shutdown, testing, shooting, ramp-up
completion, end of operations, streamers, etc.).
The following information should be recorded upon visual
observation of any marine mammal:
<bullet> Sighting ID (numeric);
[[Page 66390]]
<bullet> Watch status (sighting made by PSO on/off effort,
opportunistic, crew, alternate vessel/platform);
<bullet> Location of PSO/observer (description);
<bullet> Vessel activity at the time of the sighting (e.g.,
deploying, recovering, testing, shooting, data acquisition, other);
<bullet> PSO who sighted the animal/PSO ID;
<bullet> Time and date of sighting (GMT/UTC, MM/DD/YYYY);
<bullet> Initial detection method (description);
<bullet> Sighting cue (description);
<bullet> Vessel location at time of sighting (decimal degrees);
<bullet> Water depth (in meters);
<bullet> Direction of vessel's travel (compass direction);
<bullet> Speed (knots) of the vessel from which the observation was
made;
<bullet> Direction of animal's travel relative to the vessel
(description, compass heading);
<bullet> Bearing to sighting (degrees);
<bullet> Identification of the animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified) and the composition of the
group if there is a mix of species;
<bullet> Species reliability (an indicator of confidence in
identification) (1 = unsure/possible, 2 = probable, 3 = definite/sure,
9 = unknown/not recorded);
<bullet> Estimated distance to the animal (meters) and method of
estimating distance;
<bullet> Estimated number of animals (high, low, and best)
(numeric);
<bullet> Estimated number of animals by cohort (adults, yearlings,
juveniles, calves, group composition, etc.);
<bullet> Description (as many distinguishing features as possible
of each individual seen, including length, shape, color, pattern, scars
or markings, shape and size of dorsal fin, shape of head, and blow
characteristics);
<bullet> Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding,
traveling; as explicit and detailed as possible; note any observed
changes in behavior);
<bullet> Animal's closest point of approach (in meters) and/or
closest distance from any element of the acoustic source;
<bullet> Description of any actions implemented in response to the
sighting (e.g., delays, shutdown, ramp-up) and time and location of the
action.
<bullet> Photos (Yes or No);
<bullet> Photo Frame Numbers (List of numbers); and
<bullet> Conditions at time of sighting (Visibility; BSS).
Reporting
UT must submit a draft comprehensive report to NMFS on all
activities and monitoring results within 90 days of the completion of
the survey or expiration of the IHA, whichever comes sooner. The report
will describe the activities that were conducted and sightings of
marine mammals. The report will provide full documentation of methods,
results, and interpretation pertaining to all monitoring. The 90 day
report will summarize the dates and locations of survey operations, and
all marine mammal sightings (dates, times, locations, activities,
associated seismic survey activities).
The draft report shall also include geo-referenced time-stamped
vessel tracklines for all time periods during which airguns were
operating. Tracklines should include points recording any change in
airgun status (e.g., when the airguns began operating, when they were
turned off, or when they changed from full array to single gun or vice
versa). Geographic information system (GIS) files shall be provided in
Environmental Systems Research Institute (ESRI) shapefile format and
include the UTC date and time, latitude in decimal degrees, and
longitude in decimal degrees. All coordinates shall be referenced to
the WGS84 geographic coordinate system. In addition to the report, all
raw observational data shall be made available to NMFS. A final report
must be submitted within 30 days following resolution of any comments
on the draft report.
Reporting Injured or Dead Marine Mammals
Sighting of injured or dead marine mammals--In the event that
personnel involved in survey activities covered by the authorization
discover an injured or dead marine mammal, UT shall report the incident
to the OPR, NMFS, and the NMFS Southeast Regional Stranding Coordinator
as soon as feasible. The report must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
Vessel strike--In the event of a vessel strike of a marine mammal
by any vessel involved in the activities covered by the authorization,
UT shall report the incident to OPR, NMFS and to the NMFS Southeast
Regional Stranding Coordinator as soon as feasible. The report must
include the following information:
<bullet> Time, date, and location (latitude/longitude) of the
incident;
<bullet> Vessel's speed during and leading up to the incident;
<bullet> Vessel's course/heading and what operations were being
conducted (if applicable);
<bullet> Status of all sound sources in use;
<bullet> Description of avoidance measures/requirements that were
in place at the time of the strike and what additional measure were
taken, if any, to avoid strike;
<bullet> Environmental conditions (e.g., wind speed and direction,
BSS, cloud cover, visibility) immediately preceding the strike;
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Estimated size and length of the animal that was struck;
<bullet> Description of the behavior of the animal immediately
preceding and following the strike;
<bullet> If available, description of the presence and behavior of
any other marine mammals present immediately preceding the strike;
<bullet> Estimated fate of the animal (e.g., dead, injured but
alive, injured and moving, blood or tissue observed in the water,
status unknown, disappeared); and
<bullet> To the extent practicable, photographs or video footage of
the animal(s).
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
[[Page 66391]]
impacts or responses (e.g., critical reproductive time or location,
foraging impacts affecting energetics), as well as effects on habitat,
and the likely effectiveness of the mitigation. We also assess the
number, intensity, and context of estimated takes by evaluating this
information relative to population status. Consistent with the 1989
preamble for NMFS' implementing regulations (54 FR 40338, September 29,
1989), the impacts from other past and ongoing anthropogenic activities
are incorporated into this analysis via their impacts on the baseline
(e.g., as reflected in the regulatory status of the species, population
size and growth rate where known, ongoing sources of human-caused
mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
the species listed in Table 1, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. There is little information about the nature or severity of
the impacts, or the size, status, or structure of any of these species
or stocks that would lead to a different analysis for this activity.
NMFS does not anticipate that serious injury or mortality would
occur as a result from low-energy survey, and no serious injury or
mortality is proposed to be authorized. As discussed in the Potential
Effects of Specified Activities on Marine Mammals and Their Habitat
section, non-auditory physical effects and vessel strike are not
expected to occur. NMFS expects that all potential take would be in the
form of Level B behavioral harassment in the form of temporary
avoidance of the area or decreased foraging (if such activity was
occurring), responses that are considered to be of low severity and
with no lasting biological consequences (e.g., Southall et al., 2007,
2021).
In addition to being temporary, the maximum expected Level B
harassment zone around the survey vessel is 1,750 m. Therefore, the
ensonified area surrounding the vessel is relatively small compared to
the overall distribution of animals in the area and their use of the
habitat. Feeding behavior is not likely to be significantly impacted as
prey species are mobile and are broadly distributed throughout the
survey area; therefore, marine mammals that may be temporarily
displaced during survey activities are expected to be able to resume
foraging once they have moved away from areas with disturbing levels of
underwater noise. Because of the short duration (10 days) of the
disturbance and the availability of similar habitat and resources in
the surrounding area, the impacts to marine mammals and the food
sources that they utilize are not expected to cause significant or
long-term consequences for individual marine mammals or their
populations.
There are no rookeries, mating, or calving grounds known to be
biologically important to marine mammals within the planned survey area
and there are no feeding areas known to be biologically important to
marine mammals within the survey area. There is no designated critical
habitat for any ESA-listed marine mammals within the project area.
In summary and as described above, the following factors primarily
support our determination that the impacts resulting from this activity
are not expected to adversely affect the species or stock through
effects on annual rates of recruitment or survival:
(1) No serious injury or mortality is anticipated or authorized;
(2) No Level A harassment is anticipated or authorized, even in the
absence of mitigation measures;
(3) Take is anticipated to be by Level B harassment only consisting
of temporary behavioral changes of small percentages of the affected
species due to avoidance of the area around the survey vessel. The
relatively short duration of the planned survey (10 days) will further
limit the potential impacts of any temporary behavioral changes that
would occur;
(4) The availability of alternate areas of similar habitat value
for marine mammals to temporarily vacate the survey area during the
planned survey to avoid exposure to sounds from the activity;
(5) Foraging success is not likely to be significantly impacted as
effects on prey species for marine mammals would be temporary and
spatially limited; and
(6) The mitigation measures, including visual monitoring, ramp-ups,
and shutdowns are expected to minimize potential impacts to marine
mammals.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the monitoring and mitigation
measures, NMFS finds that the total marine mammal take from the planned
activity will have a negligible impact on all affected marine mammal
species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under section 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
NMFS is authorizing incidental take by Level B harassment of three
marine mammal species with four managed stocks. The total amount of
takes authorized relative to the best available population abundance is
less than 5 percent for 3 managed stocks and less than 13 percent for 1
managed stock (Gulf of Mexico Western Coastal stock of bottlenose
dolphin assuming all takes by Level b harassment are of this stock; see
Take Estimation subsection) (Table 6). The take numbers authorized are
considered conservative estimates for purposes of the small numbers
determination as they assume all takes represent different individual
animals, which is unlikely to be the case.
Based on the analysis contained herein of the planned activity
(including the mitigation and monitoring measures) and the anticipated
take of marine mammals, NMFS finds that small numbers of marine mammals
would be taken relative to the population size of the affected species
or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act
Section 7(a)(2) of the ESA (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
[[Page 66392]]
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 authorized 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.
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 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 determined
that the issuance of the IHA qualifies to be categorically excluded
from further NEPA review.
Authorization
NMFS has issued an IHA to UT for the potential harassment of small
numbers of three marine mammal species incidental to the marine
geophysical survey in coastal waters off of Texas that includes the
previously explained mitigation, monitoring and reporting requirements.
Dated: September 22, 2023.
Catherine Marzin,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2023-21089 Filed 9-26-23; 8:45 am]
BILLING CODE 3510-22-P
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</html>Indexed from Federal Register on September 27, 2023.
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