Notice2022-22343
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Tugs Towing Drill Rig in Cook Inlet, Alaska
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
October 14, 2022
Effective
September 14, 2022
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 two incidental harassment authorizations (IHAs) to Hilcorp Alaska LLC to incidentally harass, by Level B harassment only, marine mammals during tugs towing jack-up rig activity in Cook Inlet, Alaska.
Full Text
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<title>Federal Register, Volume 87 Issue 198 (Friday, October 14, 2022)</title>
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[Federal Register Volume 87, Number 198 (Friday, October 14, 2022)]
[Notices]
[Pages 62364-62395]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-22343]
[[Page 62364]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XC359]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Tugs Towing Drill Rig in Cook
Inlet, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of incidental harassment authorizations.
-----------------------------------------------------------------------
SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA) as amended, notification is hereby given
that NMFS has issued two incidental harassment authorizations (IHAs) to
Hilcorp Alaska LLC to incidentally harass, by Level B harassment only,
marine mammals during tugs towing jack-up rig activity in Cook Inlet,
Alaska.
DATES: These authorizations are effective from September 14, 2022
through September 13, 2023 and September 14, 2023 through September 13,
2024.
FOR FURTHER INFORMATION CONTACT: Sara Young, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed incidental harassment authorization 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.
Summary of Request
NMFS previously issued Incidental Take Regulations (ITRs) to
Hilcorp for a suite of oil and gas activities in Cook Inlet, Alaska (84
FR 37442, July 31, 2019) and issued three letters of authorization
(LOAs) under those ITRs. The ITRs covered activities including: two-
dimensional (2D) and three-dimensional (3D) seismic surveys, geohazard
surveys, and vibratory sheet pile driving. On September 17, 2019, Cook
Inletkeeper and the Center for Biological Diversity filed suit in the
District of Alaska challenging NMFS's issuance of the ITRs and LOAs and
supporting documents (the Environmental Assessment (EA) and Endangered
Species Act (ESA) Biological Opinion). In a decision issued on March
30, 2021, the court ruled largely in NMFS's favor, but found a lack of
adequate support in NMFS's record for the agency's determination that
tug towing of drill rigs in connection with production activity will
not cause take of beluga whales and remanded back to NMFS for further
analysis of tug use under the MMPA, ESA, and National Environmental
Policy Act (NEPA).
Hilcorp notified NMFS that all activities described in their
initial ITR application (2018) and for which incidental take was
authorized have already been completed or will not be completed under
the ITRs. Accordingly, NMFS has begun the process of withdrawing the
2019 ITRs. As a result, the only remaining activity to be analyzed for
incidental take and authorization thereof is the use of tugs towing a
jack-up rig.
On January 13, 2022, NMFS received a request from Hilcorp for two
back-to-back IHAs to take marine mammals incidental to tugs towing a
drill rig in Cook Inlet, Alaska. The application was deemed adequate
and complete on March 8, 2022. Hilcorp's request is for take of small
numbers of 12 species of marine mammals by Level B harassment only.
Neither Hilcorp nor NMFS expects serious injury or mortality to result
from this activity and, therefore, IHAs are appropriate.
As described in our Federal Register notice of proposed IHAs (87 FR
27597, May 9, 2022), NMFS considered the potential effects of tug
towing a jack-up rig on marine mammals. The slow, predictable, and
generally straight path of this tug configuration makes it unlikely
that marine mammals would be exposed to the tugs towing a jack-up rig
such that harassment would occur. However, there is overall potential
for exposure in combination with the nature of the tug and jack-up rig
configuration (e.g., difficult to maneuver, potential need to operate
at night), making it possible that take could occur over the total
estimated period of tug activities. Because of this possibility, NMFS
proposed take by Level B harassment from Hilcorp's use of tugs towing a
jack-up rig in Cook Inlet, Alaska.
In a letter dated April 28, 2022, Hilcorp notified NMFS of their
need to begin tugging the jack-up rig in May due to depleted energy
reserves for the Southcentral Alaska region. NMFS concurred with
Hilcorp's assessment that take of marine mammals by Level B harassment
was unlikely to occur incidental to the transport of the jack-up rig
from the Rig Tender's Dock in Nikiski to the Tyonek platform in middle
Cook Inlet, as described in Hilcorp's letter. Hilcorp completed one
move of their jack-up rig during the time that NMFS processed the
request for IHAs; this rig move was included in Hilcorp's original
application and was factored into our exposure estimate calculations
accordingly. We have therefore removed that portion of the rig move
from our analysis as it was already completed. Please refer to the
Changes from Proposed IHAs to Final IHAs section later in this document
for additional discussion. Below we discuss the IHAs as issued.
Description of Activity
Overview
Hilcorp Alaska, LLC (Hilcorp) plans to carry out activities that
will occur during two separate consecutive one-year IHA periods--from
September 1, 2022, to August 31, 2023 (Year 1), and from September 1,
2023, to August 31, 2024 (Year 2). Hilcorp plans to use three
[[Page 62365]]
ocean-going tugs to tow a jack-up rig in support of plugging and
abandonment (P&A) of an existing well and to support production
drilling at other locations in middle Cook Inlet and Trading Bay over
the course of 2 years.
Dates and Duration
The schedule for Hilcorp's P&A and production drilling activities
is provided in Table 1 below. The noise-producing rig-towing activities
for which take is authorized would occur in between those activities,
for approximately 14 days per year for Year 1 and 16 days for Year 2.
Table 1--Dates and Durations of Planned Activities in Cook Inlet
----------------------------------------------------------------------------------------------------------------
Project type Cook Inlet region Timing Duration of activity *
----------------------------------------------------------------------------------------------------------------
Year 1:
Plug and Abandonment of Well Middle Cook Inlet...... April-November......... 30 days.
17589.
Production Drilling............. Middle Cook Inlet April-November......... 180 days.
Trading Bay.
Year 2:
Production Drilling............. Middle Cook Inlet April-November......... 180 days.
Trading Bay.
----------------------------------------------------------------------------------------------------------------
* Duration is in reference to the supported activity that requires the jack-up rig to be in a specific location.
It is not reflective of the duration or the number of days the jack-up rig is towed.
Specific Geographic Region
Hilcorp's activities will take place in Cook Inlet, Alaska. For the
purposes of this project, lower Cook Inlet refers to waters south of
the East and West Forelands; middle Cook Inlet refers to waters north
of the East and West Forelands and south of Threemile River on the west
and Point Possession on the east; Trading Bay refers to waters from
approximately the Granite Point Tank Farm on the north to the West
Foreland on the south; and upper Cook Inlet refers to waters north and
east of Beluga River on the west and Point Possession on the east. A
map of the specific area in which Hilcorp plans to operate is provided
in Figure 1 below.
BILLING CODE 3510-22-P
[[Page 62366]]
[GRAPHIC] [TIFF OMITTED] TN14OC22.069
BILLING CODE 3510-22-C
Detailed Description of Specific Activity
Hilcorp plans to use three tugs to pull and position a jack-up rig
in support of well plugging and abandonment (P&A) and support of
production drilling by using the rig as a temporary drilling platform.
Hilcorp plans to use the jack-up rig Spartan 151, or similar. A jack-up
rig is a type of mobile offshore drill unit used in offshore oil and
gas drilling activities. It is comprised of a buoyant mobile platform
or hull with moveable legs that are adjusted to raise and lower
[[Page 62367]]
the hull over the surface of the water. The Spartan 151 (or similar)
will be towed via three ocean-going tugs. The horsepower (hp) of each
of the three tugs used to tow the jack-up rig may range between 4,000
and 8,000. Three tugs are needed to safely and effectively pull the
jack-up rig into the correct position where it can be temporarily
secured to the seafloor. Specifications of the tugs anticipated for use
are provided in Table 2 below. If these specific tugs are not
available, the tugs contracted would be of similar size and power to
those listed in Table 2.
Table 2--Description of Tugs Towing the Jack-Up Rig
------------------------------------------------------------------------
Vessel name Specifications
------------------------------------------------------------------------
M/V Bering Wind........................... 22-m length x 10-m breadth,
144 gross tonnage.
M/V Anna T................................ 32-m length x 11-m breadth,
160 gross tonnage.
M/V Bob Franco............................ 37-m length x 11-m breadth,
196 gross tonnage.
------------------------------------------------------------------------
The amount of time the tugs are under load transiting, holding, and
positioning the jack-up rig in Cook Inlet is tide-dependent. The power
output of the tugs depends on whether the tugs are towing with or
against the tide and can vary across a tide cycle as the current
increases or decreases in speed over time. Hilcorp will make every
effort to transit with the tide (which requires lower power output) and
minimize transit against the tide (which requires higher power output).
The jack-up rig will be transported via towing by three ocean-going
tugs, with final demobilization at the Rig Tenders Dock in Nikiski,
Alaska (where mobilization began). Towing the jack-up rig northward
with an incoming tide or southward with an outgoing tide requires less
than half power, generally only 20 to 30 percent of total power output
(Durham 2021, pers. comm.). A high slack tide is preferred to position
the jack-up rig on an existing platform or well site. The relatively
slow current and calm conditions at a slack tide enable the tugs to
perform the fine movements necessary to safely position the jack-up rig
within several feet of the platform. Positioning and securing the jack-
up rig is generally performed at high slack tide rather than low slack
tide to pin the legs down at an adequate height to ensure the hull of
the jack-up rig remains above the water level of the subsequent
incoming high tide. Because 12 hours elapse between each high slack
tide, tugs are generally under load for those 12 hours during rig
mobilization and demobilization, even if the towed distance is small,
as high slack tides are preferred to both attach and detach the jack-up
rig from the tugs. Once the tugs are on location with the jack-up rig
at high slack tide (12 hours from the previous departure), there is a 1
to 2-hour window when the tide is slow enough for the tugs to initiate
positioning the jack-up rig and pin the legs to the seafloor on
location. The tugs are estimated to be under load, generally at half-
power conditions or less, for up to 14 hours from the time of departure
through the initial positioning attempt of the jack-up rig. If the
first positioning attempt takes longer than anticipated, the increasing
current speed prevents the tugs from safely positioning the jack-up rig
on location. If the first positioning attempt is not successful, the
jack-up rig will be pinned down at a nearby location and the tugs will
be released from the jack-up rig and no longer under load. The tugs
will remain nearby, generally floating with the current. Approximately
an hour before the next high slack tide, the tugs will re-attach to the
jack-up rig and reattempt positioning over a period of 2 to 3 hours.
Positioning activities are generally at half power. If a third attempt
is needed, the tugs would be under load holding or positioning the
jack-up rig on a second day for up to 5 hours. The vast majority of the
time, the jack-up rig can be successfully positioned over the platform
in one or two attempts.
A location-to-location transport (e.g., platform-to-platform) of a
jack-up rig is conducted similarly to the mobilization from the Rig
Tenders Dock described above with one main difference. In a location-
to-location transport in middle Cook Inlet or Trading Bay, there is no
harbor available for temporary staging to avoid transiting against the
tide. Maintaining position of the jack-up rig against the tidal current
can require more than half power (up to 90 percent power at the peak
tidal outflow). However, greater than half power effort is only needed
for short periods of time during the maximum tidal current, expected to
be no more than 3 hours maximum. During a location-to-location
transport, the tugs will transport the jack-up rig traveling with the
tide in nearly all circumstances except in situations that threaten
human safety and/or infrastructure integrity. There may be a situation
wherein the tugs pulling the jack-up rig begin transiting with the tide
to their next location, miss the tide window to safely set the jack-up
rig on the platform or pin it nearby, and so have to transport the
jack-up rig against the tide to a safe harbor. Tugs may also need to
transport the jack-up rig against the tide if large pieces of ice or
extreme wind events threaten the stability of the jack-up rig on the
platform.
Although the variability in power output from the tugs can range
from an estimated 20 percent to 90 percent throughout the hours under
load with the jack-up rig, as described above, the majority of the
hours (spent transiting, holding, and positioning) occur at half power
or less. See the Estimated Take section below for more detail on
assumptions related to power output.
Year 1--For the first year of activity, Hilcorp will use three tugs
to pull the jack-up rig for P&A of Well 17589, which began in 2021 but
was not completed due to equipment sourcing issues. Prior to pinning
the jack-up rig legs to the seafloor, a multi-beam sonar may be used to
ensure the seafloor is clear of debris that may impact the ability to
pin down the legs of the platform. The multi-beam echosounder emits
high frequency (240 kilohertz (kHz)) energy in a fan-shaped pattern of
equidistant or equiangular beam spacing. The multi-beam sonar operates
at a frequency outside of marine mammal hearing range and is not
addressed further in our analysis. After the rig is secure, divers
enter the water and use hand tools to complete the P&A process. In
addition to the hand tools, the divers will also use water jets to wash
away debris and marine growth on the structure (e.g., a CaviDyne
CaviBlaster). Based on measurements conducted by Hilcorp during 2017
use of water jets, the source level for the CaviBlaster[supreg] was
estimated as 176 decibels (dB) re 1 micropascal ([mu]Pa) root mean
square (rms) with a Level B harassment threshold of 860 m, with most
energy concentrated above 500 Hz with a dominant tone near 2 kHz.
Hilcorp plans to put a protected species observer (PSO) on watch to
monitor the full extent of the harassment zone and shutdown when a
marine mammal approaches the zone during water jet use. Because of
this, Hilcorp is not requesting take associated with water jet use and
it is not considered further in our analysis.
Hilcorp also plans to tug the jack-up rig to existing platforms in
middle Cook Inlet and Trading Bay in support of production drilling
activities from existing platforms and wellbores. Production drilling
itself creates some small level of noise due to the use of generators
and other potentially noise-generating equipment. Furie Operating
Alaska, LLC, performed detailed underwater acoustic measurements in the
vicinity of the Spartan 151 in 2011
[[Page 62368]]
(Marine Acoustics Inc., 2011) northeast of Nikiski Bay in water depths
of 24.4 to 27.4 m (80 to 90 ft). Primary sources of rig-based acoustic
energy were identified as coming from the D399/D398 diesel engines, the
PZ-10 mud pump, ventilation fans, and electrical generators. The source
level of one of the loudest acoustic sources, the diesel engines, was
estimated to be 137 dB re 1 [mu]Pa rms at 1 m in the 141 to 178 Hz
frequency range. Based on this measured level, the 120 dB rms acoustic
received level isopleth would be approximately 50 m away from where the
energy enters the water (jack-up leg or drill riser). Sound source
levels were also measured by JASCO (a company) for drilling and mud
pumping from the Yost jack-up rig in 2016. The primary sources of
continuous sounds measured from the Yost were drilling (158 dB) and
mu167d pumping (148.4 dB), producing 120 dB isopleths of 330 and 225
meters, respectively. The acoustic energy of drilling noise was found
to be predominantly under 500 Hz (Denes and Austin, 2016a). Denes and
Austin (2016) did not record other rig-based activities including
cementing, running casing, and tripping in and out of the hole with
drill string; however, these activities may also produce sounds similar
to mud pumping. There is open water in all directions from the drilling
location. Additionally, Hilcorp plans to monitor the area around the
drilling platform for 30 minutes prior to starting drilling activities
and delay their activity if marine mammals are seen close to the
platform. Any marine mammal approaching the rig would be fully aware of
its presence long before approaching or entering the zone of influence
for behavioral harassment, and we are unaware of any specifically
important habitat features (e.g., concentrations of prey or refuge from
predators) within the rig's zone of influence that would encourage
marine mammal use and exposure to higher levels of noise closer to the
source. Given the absence of any activity-, location-, or species-
specific circumstances or other contextual factors that would increase
concern, we do not expect routine drilling noise to result in the take
of marine mammals.
In support of these activities, helicopters and support vessels
transit from the mainland to the production sites to mobilize personnel
and supplies. Helicopters will fly at 1,500 ft (457 m) or higher unless
human safety is at risk or it is operationally impossible (e.g.,
takeoff and landing points are so close together the aircraft cannot
reach 1,500 ft or 30 m). During take-off and landing of a helicopter,
it is expected that only a small amount of sound would penetrate the
water because the helicopter will be moving vertically over the helipad
and most of the sound is reflected and does not penetrate at angles
greater than 13 degrees from vertical. Additionally, the platforms that
helicopters are navigating to/from are already 100 or more feet above
sea level, further reducing potential for harassment of marine mammals
such that take is not requested nor authorized. Vessel trips to and
from the location of the jack-up rig are expected to increase by two
trips per day above normal activity levels. Hilcorp plans to maintain
watch for marine mammals during supply vessel trips, stay at least 100
yards (91 m) away from marine mammals, reduce speed in poor visibility,
and handle supply vessels such that an encounter with a marine mammal
is unlikely and additional take for supply vessel activities is not
requested nor authorized.
Year 2--For the second year of activity, Hilcorp does not plan to
conduct P&A activities with the jack-up rig and will only be tugging
the jack-up rig in support of production drilling activities.
The specific configuration of tugs towing the jack-up-rig as used
by Hilcorp has not been analyzed previously. Hilcorp contracted JASCO
Applied Sciences to conduct a sound source verification (SSV) of their
tugs in operation in Cook Inlet during October 2021. This SSV measured
tugs pulling the jack-up-rig at various power outputs (Lawrence et al.,
2022). This SSV returned a source level of 167.3 dB re 1 [mu]Pa for the
20 percent power scenario and a source level of 205.9 dB re 1 [mu]Pa
for the 85 percent power scenario. Assuming a linear scaling of tug
power, a source level of 185 dB re 1 [mu]Pa was then calculated as a
single point source level for three tugs operating at 50 percent power
output. This is approximately five dB higher than the literature
summary described below.
Hilcorp conducted a literature review of available source level
data for tugs under load in varying power output scenarios. Table 3
below provides values of measured source levels for tugs varying from
2,000 to 8,200 horsepower. For the purposes of this table, berthing
activities could include tugs either pushing or pulling a load. The
sound source levels appear correlated to speed and power output, with
full power output and higher speeds generating more propeller
cavitation and greater sound source levels than lower power output and
lower speeds. Additional tug source levels are available from the
literature, but they are not specific to tugs under load (rather they
measured values for tugs during activities such as transiting, docking,
and anchor pulling). For a summary of these additional tug values, see
Table 7 in Hilcorp's application.
Table 3--Literature Values of Measured Tug Source Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source level
Vessel Vessel length Speed (knots) Activity @1 m (re: 1 Horsepower Reference
(m) [micro]Pa)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Eagle................................ 32 9.6 Towing barge............ 173 6,770 Bassett et al., 2012.
Valor................................ 30 8.4 Towing barge............ 168 2,400
Lela Joy............................. 24 4.9 Towing barge............ 172 2,000
Pacific Eagle........................ 28 8.2 Towing barge............ 165 2,000
Shannon.............................. 30 9.3 Towing barge............ 171 2,000
James T Quigg........................ 30 7.9 Towing barge............ 167 2,000
Island Scout......................... 30 5.8 Towing barge............ 174 4,800
Chief................................ 34 11.4 Towing barge............ 174 8,200
Lauren Foss.......................... 45 N/A Berthing barge.......... 167 8,200 Austin et al., 2013.
Seaspan Resolution................... 30 N/A Berthing at half power.. 180 6,000 Roberts Bank Terminal 2
Technical Report,
2014.
Seaspan Resolution................... 30 N/A Berthing at full power.. 200 6,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 62369]]
The Roberts Bank Terminal 2 Technical Report (2014), although not
in Cook Inlet, includes repeated measurements of the same tug operating
under different speeds and loads. This allows for a comparison of
source levels from the same vessel at half power versus full power,
which is an important distinction for Hilcorp's activities, as a small
fraction of the total time spent by tugs under load will be at greater
than 50 percent power. The Seaspan Resolution's half-power berthing
scenario has a sound source level of 180 dB re 1 [mu]Pa at 1 m. In
addition, the Roberts Bank Report (2014) analyzed 650 tug transits
under varying load and speed conditions and reported mean tug source
levels of 179.3 dB re 1 [mu]Pa at 1 m, the 25th percentile was 179.0 dB
re 1 [mu]Pa at 1 m, and 5th percentile source levels were 184.9 dB re 1
[mu]Pa at 1 m.
Based solely on the literature review, a source level of 180 dB for
a tug under load would be appropriate. However, Hilcorp's use of a
three tug configuration would increase the literature source level to
approximately 185dB. As one or two tugs are primarily under load, the
third tug sits off to the side. NMFS still considers these tugs to be
simultaneous sources. When considered in conjunction with the
additional tugs present in the configuration as well as the SSV
conducted by JASCO for Hilcorp's specific configuration, a source level
of 185 dB for tugs towing a jack-up rig was carried forward for
analysis.
Mitigation, monitoring, and reporting measures are described in
detail later in this document (please see Mitigation and Monitoring and
Reporting).
Comments and Responses
A notice of NMFS's proposal to issue IHAs to Hilcorp was published
in the Federal Register on May 9, 2022 (87 FR 27597). That notice
described, in detail, Hilcorp's activity, the marine mammal species
that may be affected by the activity, and the anticipated effects on
marine mammals. During the 30-day public comment period, NMFS received
comments from Hilcorp, the Bureau of Ocean Energy Management (BOEM),
and the Center for Biological Diversity (CBD) in conjunction with Cook
Inletkeeper and Kachemak Bay Conservation Society (this group comment
letter is referenced as CBD throughout this notice). These letters are
available online at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llc-oil-and-gas-activities-cook-inlet-alaska-0">https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llc-oil-and-gas-activities-cook-inlet-alaska-0</a>. A summary of the commenters' recommendations as well as
NMFS' responses is below.
Comment 1: NMFS received comments about how the proposed IHAs would
relate to the Incidental Take Regulations (ITRs) NMFS issued to Hilcorp
in 2019 (84 FR 37442, July 30, 2019). CBD commented that NMFS cannot
``segment'' its MMPA analysis for the activities proposed under the
IHAs from its authorization of Hilcorp's oil and gas activities under
the 5-year ITRs. Additionally, Hilcorp requested that NMFS withdraw the
ITRs.
Response: The activities for which take was analyzed in the ITRs
have already occurred or, per Hilcorp, will not occur during the
remaining period of the ITR, which currently expires on July 30, 2024.
Because none of the activity for which take was authorized under the
ITRs is planned to occur under the ITRs, NMFS and Hilcorp determined
there would be no benefit to undertaking the process of re-evaluating
the ITRs. Instead it was determined that IHAs under section
101(a)(5)(D) would be an efficient vehicle for addressing incidental
take from tug activities in a timely fashion, should authorization be
needed, particularly compared to the process for rulemaking under
section 101(a)(5)(A).
Hilcorp accordingly applied for two IHAs and NMFS evaluated the
potential for take of marine mammals incidental to the tug activity
Hilcorp included in its application. Given the type of activity Hilcorp
plans to conduct, the fact that any potential take would be in the form
of Level B harassment, only, and the timeframe of those activities,
IHAs are appropriate. This is the course of action NMFS would advise
for any applicant planning to conduct 2 years of approximately 14 days
and 16 days of take-related activity per year, respectively, with the
potential to result in take by harassment only.
As indicated above, and at Hilcorp's request, NMFS is undertaking
the process to withdraw the ITRs to reduce any confusion. NMFS will not
issue any more LOAs pursuant to the ITRs to authorize take incidental
to Hilcorp's tug towing activities. Thus there is no possibility for
NMFS to authorize incidental take of beluga whales simultaneously
through an IHA and the ITRs.
Comment 2: BOEM commented that NMFS' Federal Register (FR) notice
did not discuss potential effects of helicopters and support vessels
described in Hilcorp's application for IHAs and that NMFS may benefit
from analysis of effects to marine mammals from these activities.
Response: NMFS briefly discussed these activities in the Detailed
Description of Specific Activity in the notice of proposed IHAs,
following the discussion of water jets. That paragraph includes a
discussion of why these activities were not considered further.
Comment 3: BOEM commented that NMFS could add clarity as to why 185
dB was used as an estimated source level for the multi-tug
configuration by referring readers to the JASCO monitoring report for
the sound source verification of Hilcorp's sources.
Response: NMFS omitted this source inadvertently. We have now
included Lawrence et al. (2022) in our references for further
information regarding the sound source verification used to derive a
source level of 185 dB for the three-tug combination.
Comment 4: BOEM commented that NMFS may want to consider effects to
Pacific white-sided dolphins based on an acoustics report (Castellote
et al., 2020).
Response: Based on this report and other information described
below, NMFS has added take of Pacific white-sided dolphins to our
analysis and authorizations. See Description of Marine Mammals in the
Area of Specified Activities section for more discussion of the species
and why they are included in our analysis.
Comment 5: BOEM noted page 27621 of the notice of proposed IHAs
listed requirements for monitoring of pile driving activities.
Response: These requirements were included in error and have been
removed from the final notice.
Comment 6: Hilcorp commented that the notice of proposed IHAs and
draft EA incorrectly refers to Hilcorp's planned tugging activities as
the ``proposed activity'' when the proposed activity from NMFS'
perspective is the proposed issuance of IHAs to take marine mammals
incidental to Hilcorp's planned activities.
Response: Hilcorp is correct and NMFS has clarified Hilcorp's
planned activities from NMFS' activities in all documents.
Comment 7: Hilcorp contests NMFS' characterization of the project
area as a ``non-industrial setting'' prior to the onset of Hilcorp's
tugging activities. The oil and gas facilities in Cook Inlet, including
Hilcorp's platforms, have been active, with daily activities, for the
past 60 years.
Response: NMFS agrees that this area is not pristine, as Hilcorp's
platforms and development structures are already in existence. However,
Hilcorp's activities will introduce additional anthropogenic activity
into the area,
[[Page 62370]]
such as increased vessels around the platforms, helicopter trips for
personnel, supplies, etc. NMFS has clarified the characterization of
the action area accordingly.
Comment 8: Hilcorp recommended that NMFS more clearly describe why
any incidental marine mammal harassment related to tug-towing
activities is likely to be very low due to the characteristics of those
activities in the notice of issuance of IHAs and final EA.
Response: NMFS agrees with Hilcorp's characterization that a multi-
tug configuration under load moves in a slow, predictable pattern that
is unlikely to surprise marine mammals in the area and, further,
animals near industrial activities may become habituated to regular
activities in the area, as has been shown for Cook Inlet belugas around
the Port of Anchorage, for example (61 North Environmental, 2020).
However, given the sources levels, there is still the potential that
some belugas may behaviorally respond in a manner that would qualify as
a take. NMFS characterizes the type of harassment (behavioral
disturbance only) that may occur from tugs in this Federal Register
notice and has authorized Level B harassment out of caution due to
several combined factors, as described in the Potential Effects of
Specified Activities on Marine Mammals and their Habitat section.
Comment 9: Hilcorp recommends that NMFS clearly express its finding
that the incidental harassment levels for each IHA constitutes a
``small number'' for each marine mammal stock regardless of NMFS's
``one-third'' standard.
Response: NMFS has made a small numbers finding for each IHA
individually. The quantitative rationale for determining these numbers
are ``small'' is put forth in Table 15 below.
Comment 10: Hilcorp requests that NMFS clarify that the renewal
process is not necessary for the Year 2 IHA to become effective.
Hilcorp specifically applied for, and NMFS proposed to issue, two
separate, stand-alone IHAs. The Year 2 IHA would not be a ``renewed''
version of the Year 1 IHA. Hilcorp anticipates no need for renewal of
the Year 1 IHA and requests removal of the renewal provision from the
IHAs.
Response: Hilcorp is correct that the Year 2 IHA is not dependent
upon a renewal of Year 1 and is a completely separate authorization
from the Year 1 IHA. NMFS issued the Year 1 IHA to Hilcorp effective
through September 13, 2023. NMFS has also issued a Year 2 IHA to
Hilcorp with effective dates from September 14, 2023 to August 13,
2024. Further, at Hilcorp's request, NMFS will not consider a renewal
of the Year 1 IHA and has removed the renewal provision from these
IHAs.
Comment 11: Hilcorp recommends that NMFS clarify whether or not the
EA relies upon the NEPA regulatory amendments recently adopted by the
Council for Environmental Quality (CEQ) that became effective on May
20, 2022 (87 FR 2,453, April 20, 2022).
Response: Per NMFS' internal guidance dated June 17, 2022, NEPA
reviews for actions initiated after September 14, 2020, but prior to
May 20, 2022, will be conducted according to the 2020 CEQ regulations.
In accordance with this guidance, NMFS' Environmental Assessment for
this action references the 2020 CEQ regulations.
Comment 12: Hilcorp suggested several corrections or changes for
clarity or to improve accuracy throughout the FR notice. Hilcorp
commented that NFMS incorrectly characterized the straight line towing
distance in the Marine Mammal Hearing section of the proposed IHA
notice as 37 km when the distance used in the analysis was 64 km (40
mi). Hilcorp also comments that use of the phrase ``approximately 7
km'' was confusing as that was an estimation of the diameter of the
ensonified area and that 3.8 km radius is a more precise
characterization of the analysis of the ensonified area.
Response: These errors and clarifications have been fixed for this
notice of the final IHAs.
Comment 13: The Center for Biological Diversity (CBD) recommended
that NMFS stop allowing take of Cook Inlet beluga whales unless and
until the agency conducts a comprehensive evaluation of the numerous
threats. They note that NMFS developed 5-year action plans for each of
the ``Species in the Spotlight'' that outline short-term efforts vital
for stabilizing their populations and preventing their extinction. The
first of the ``Key Actions Needed 2016-2020'' in NMFS's Species on the
Spotlight Cook Inlet Beluga Whale 5-Year Action Plan is ``Reduce the
Threat of Anthropogenic Noise in Cook Inlet Beluga Whale Habitat.''
They further note that the NMFS' Recovery Plan for Cook Inlet beluga
whales (2016) (Recovery Plan) lists tugboats as the highest noise
threat to critically endangered species.
Response: NMFS shares CBD's concern regarding the impacts of human
activities on Cook Inlet beluga whales and is committed to supporting
the conservation and recovery of the species. Under section
101(a)(5)(D) of the MMPA, NMFS considers the at risk status of Cook
Inlet beluga whales (and other species) in both the negligible impact
analysis and through our consideration of impact minimization measures
that will support the least practicable adverse impact on those
species. For example, the Hilcorp final rule included shutdown zones
for Cook Inlet beluga whales that extended well beyond standard
shutdown zones all the way to the Level B harassment isopleth. However
section 101(a)(5)(D) also mandates that NMFS ``shall issue'' an IHA if
we are able to make the necessary findings for any specified activity
for which incidental take is requested.
In accordance with our implementing regulations at 50 CFR
216.104(c), we use the best available scientific evidence to determine
whether the taking by the specified activity within the specified
geographic region will have a negligible impact on the species or stock
and will not have an unmitigable adverse impact on the availability of
such species or stock for subsistence uses. Based on the scientific
evidence available, NMFS determined that the take incidental to
Hilcorp's tugging of the jack-up rig, which is primarily acoustic in
nature, transient, and of a low level, would have no more than a
negligible impact and no unmitigable adverse impact on availability of
marine mammals for subsistence uses. Moreover, Hilcorp proposed and
NMFS has required in the IHAs a rigorous mitigation plan to further
reduce potential impacts to Cook Inlet beluga whales and other marine
mammals to the lowest level practicable. Protected species observers
are required to conduct monitoring during all jack-up rig towing
activity. Since publication of the proposed IHAs, aerial surveys have
been incorporated to monitor for beluga presence when towing to or from
the Tyonek platform as the more northern location is approaching an
area of known Cook Inlet beluga whale use.
Our analysis indicates that issuance of these IHAs will not
contribute to or worsen the observed decline of the Cook Inlet beluga
whale population. Additionally, the ESA Biological Opinion determined
that the issuance of these IHAs is not likely to jeopardize the
continued existence of the Cook Inlet beluga whales or the western
distinct population segment of Steller sea lions or to destroy or
adversely modify Cook Inlet beluga whale critical habitat. The
Biological Opinion also outlined Terms and Conditions and Reasonable
and Prudent Measures to reduce impacts, which have been incorporated
into the IHAs, including the aerial surveys discussed in the Mitigation
section
[[Page 62371]]
below. Therefore, based on the analysis of potential effects, the
parameters of the activity, and the rigorous mitigation and monitoring
program, NMFS determined that the taking from the specified activity
for Year 1 and for Year 2 would have a negligible impact on the Cook
Inlet beluga whale stock.
Moreover, Hilcorp's jack-up rig towing activity would take only
small numbers of marine mammals relative to their population sizes.
Further, these takes represent one annual disturbance event for each of
these individuals, or perhaps a few individuals could be disturbed a
few times, in which case the number of impacted individual whales is
even lower. As described in the Federal Register notice of proposed
IHAs, NMFS used a method that incorporates density of marine mammals
overlaid with the anticipated ensonified area to calculate an estimated
number of takes for belugas, which was estimated to be less than 8
percent of the stock abundance, which NMFS considers small.
Regarding CBD's comment about tugboat noise, NMFS' Recovery Plan
ranks noise from tugboats as the most important source that could
potentially interfere with Cook Inlet beluga whale recovery based on
signal characteristics and spatio-temporal acoustic footprint. However,
notably, the Recovery Plan is referencing tugboat noise as a whole
across all vessels and the entirety of Cook Inlet, not Hilcorp's
specified activity in the specified location and geographic region,
which is likely a small portion of overall tugboat use in Cook Inlet
throughout the year. NMFS' biological opinion on NMFS' IHAs for
Hilcorp's activity addressed the impacts of the marine mammal take NMFS
is authorizing in the context of both the environmental baseline and
the cumulative effects (including tugboats) and found that it likely
would not jeopardize Cook Inlet beluga whales or destroy or adversely
modify their Critical Habitat. In the MMPA analysis, NMFS addresses the
signal characteristics and spatio-temporal overlap of Hilcorp's
specific tug activity in the Federal Register notice and has authorized
take accordingly.
In addition to implementing mitigation and measures to minimize the
impact of Hilcorp's activity, more broadly NMFS is taking several
proactive steps to address the decline of the species. NMFS provides
online platforms that allow public access to search for and review NOAA
Fisheries permits and authorizations, as well as consultations under
section 7 of the ESA. Additionally, NMFS is supporting the development
of a population consequences of disturbance model to further refine
information about the effects of stressors on Cook Inlet beluga whale
behavior, energetic costs, and vital rates. NMFS continues to conduct
outreach and education to various stakeholders to minimize the
potential for unauthorized take of Cook Inlet beluga whales. Lastly,
NMFS is developing site-specific stranding response and disaster
response guidelines for Cook Inlet, which could inform responses and
further reduce impacts to Cook Inlet beluga whales.
Comment 14: CBD commented that the Recovery Plan recommends a
review of the current system of allocation of takes by harassment of
beluga whales to better reduce cumulative effects of harassment takes
by numerous projects. CBD provides examples for the number of takes
authorized by NMFS for various time periods, citing Migura and Bollini
(2021).
Response: We note first that the Migura and Bollini (2021) paper
cited by CBD seems to have led to a misunderstanding of the takes
authorized or permitted by NMFS. In summary, CBD asserts that NMFS
authorized nearly 120,000 takes of Cook Inlet belugas from 2017 to 2025
and that in 2020 alone, NMFS authorized the equivalent of 50 percent of
the entire Cook Inlet beluga whale population to be ``incidentally''
harassed by industrial projects in the Inlet, such as oil and gas
development and pile driving activities.
The vast majority of the asserted ~120,000 total takes (99
percent), including all of the very small amount of take by Level A
harassment, were authorized under directed research or enhancement
permits, which support research or actions identified in the Recovery
Plan to address Cook Inlet beluga whale recovery goals. Further, the
vast majority (~99 percent) of the total permitted research or
enhancement take numbers cited by CBD are low-level MMPA Level B
harassment from remote or non-invasive procedures that are considered
not likely to adversely affect listed species pursuant to the ESA
(i.e., no associated take under the ESA is either expected to occur or
exempted for those specific activities). We further note that based on
the required post-research reporting from this 9-year period, an
average of 25 percent of the permitted takes actually occurred. For the
Directed Take Program, scientific research and enhancement permits
authorize intentional close approaches that target marine mammals and
that may result in harassment. These permitted takes generally are a
larger number than the actual takes that occur because researchers need
the ability to work in the field without running out of takes mid-
season when optimal conditions and opportunities arise to meet their
stated research objectives. Factors such as weather, funding, the
pandemic, etc., affect whether takes can be used.
Regarding the comprehensive evaluation and minimization of
permitted takes, we reference the analysis that has already been
completed through NMFS' 2019 Biological and Conference Opinion on the
Proposed Implementation of a Program for the Issuance of Permits for
Research and Enhancement Activities on Cetaceans in the Arctic,
Atlantic, Indian, Pacific, and Southern Oceans (NMFS, 2019), which
determined that the research and enhancement takes permitted by the
program would not jeopardize the existence of any of the affected
species. As part of our programmatic framework for permitting directed
take of ESA species, the Permits and Conservation Division will
continue to closely evaluate the number and manner of Cook Inlet beluga
whale takes requested by each applicant, how the proposed research ties
to recovery plan goals, and the collective number of authorized and
requested takes to consider the potential cumulative impact of the
activities to the population. Each directed take annual report is
reviewed to understand how authorized takes were actually used and to
closely monitor the impacts that permitted research methods are having
on the target animals.
NMFS also has an active role on the Research subcommittee of the
Cook Inlet Beluga Whale Recovery Implementation Task Force. Starting in
2021 the subcommittee increased efforts to monitor and coordinate
research undertaken on Cook Inlet beluga whales each year. This effort
includes pre- and post-season meetings with all parties conducting
these studies to (1) coordinate field efforts and minimize harassment
of whales, (2) learn of the latest findings by these groups and others.
The subcommittee also plans to review new findings about threats listed
in the Recovery Plan (NMFS, 2016) and identify data gaps as potential
avenues for future research.
Regarding the incidental takes authorized for 2020, those takes
represent instances of exposure above the Level B harassment threshold
that could occur within a day. In other words, if those approximately
130 takes were assumed to be 130 separate individual whales, it would
mean that those individual whales were each behaviorally disturbed on
one day in that year. The more likely scenario is
[[Page 62372]]
that some of those 130 exposures were takes of the same whale on a few
different days, and in fact a lesser number of individuals were taken,
but still on only a few days within a year. In all cases, the necessary
findings under MMPA and ESA were made prior to the authorization of the
take. Further, ITAs issued for activities that may take Cook Inlet
beluga whales typically include enhanced protective measures for beluga
whales that include delaying the activity or shutting down if a beluga
is sighted within the Level B harassment zone and avoiding activities
in important feeding areas, such as the Susitna Delta. These measures
ensure that in the unlikely event that a beluga whale is harassed by
activities covered by an ITA, the impacts are expected to be of a
comparatively low level of severity.
Comment 15: CBD commented that NMFS' actions contradict the
recommendations of the Marine Mammal Commission, which has repeatedly
urged NMFS to stop issuing authorizations until the agency better
understands the decline in abundance.
Response: CBD cites letters NMFS received from the Marine Mammal
Commission (MMC) for previous proposed incidental take authorizations
before 2021 recommending NMFS refrain from authorizing take of Cook
Inlet beluga whales until more is understood about the decline in
abundance. NMFS responded to those comment letters (e.g., 84 FR 37451,
July 31, 2019) and we incorporate that response by reference. NMFS did
not receive a comment letter from the MMC regarding the proposed IHAs
for Hilcorp, but we refer the reader to the responses to comments 13
and 14 above.
Comment 16: CBD commented that the MMPA states that IHAs are valid
for periods of not more than 1 year, but that NMFS is proposing a
series of IHAs for the next 3 years without conducting a comprehensive
analysis of take across all 3 years.
Response: Incidental harassment authorizations issued under section
101(a)(5)(D) for a specified activity are limited to periods of 1 year
or less. Each IHA must satisfy the negligible impact standard for the
authorized taking and include the means of effecting the least
practicable adverse impact on the species or stock and its habitat and,
where relevant, on the availability of such species or stock for taking
for subsistence uses (i.e., mitigation). NMFS considered Hilcorp's
request for two IHAs for two distinct specified activities (identified
as Year 1 and Year 2 activities) and, therefore, performed two distinct
negligible impact analyses (because NMFS removed the possibility of a
renewal of the IHAs at Hilcorp's request, there will not be a
possibility for a third year). NMFS has a documented history of issuing
consecutive IHAs to the same applicant, including sequential IHAs
authorizing take of Cook Inlet beluga whales (85 FR 19294, April 6,
2020; 85 FR 1140, January 9, 2020; 85 FR 68291, October 28, 2020).
Although it is not clear what is meant by a ``comprehensive'' analysis,
under NMFS' implementing regulations for the MMPA, our negligible
impact analyses take into account the ``baseline''; moreover, under
NEPA, NMFS' EA considers all anthropogenic activities that NMFS is
aware of, including those for which take is not authorized in the
cumulative effects section and incorporates where appropriate into the
environmental baseline under the ESA, NMFS' biological opinion
considered the same types of activities in their environmental baseline
and cumulative effects discussions.
Regarding the potential for a third year of activities through the
issuance of a renewal at a later date, please see the response to
comment 17.
Comment 17: CBD commented that issuance of renewals of IHAs via an
expedited process is unlawful as it circumvents public comment timing
laid out in the MMPA.
Response: NMFS' IHA renewal process meets all statutory
requirements. All IHAs issued, whether an initial IHA or a renewal, are
valid for a period of not more than 1 year; the public has 30 days to
comment on proposed IHAs, with a cumulative total of 45 days for IHA
renewals. The Request for Public Comments section in the notice of
proposed IHA made clear that the agency was seeking comment on both the
initial proposed IHA for this project and the potential issuance of a
renewal. Because any renewal (as explained in the Request for Public
Comments section) is limited to another year of identical or nearly
identical activities (as described in the Description of Proposed
Activity) or the same activities that were not completed within the 1-
year period of the initial IHA, reviewers have the information needed
to effectively comment on both the immediate proposed IHA and a
possible 1-year renewal, should the IHA holder choose to request one in
the coming months.
In prior responses to comments about IHA Renewals (e.g., 84 FR
52464, October 02, 2019; 85 FR 53342, August 28, 2020), NMFS has
explained how the Renewal process, as implemented, is consistent with
the statutory requirements contained in section 101(a)(5)(D) of the
MMPA, provides additional efficiencies beyond the use of abbreviated
notices, and, further, promotes NMFS' goals of improving conservation
of marine mammals and increasing efficiency in the MMPA compliance
process. Therefore, we intend to continue implementing the Renewal
process.
In this case, as already stated, at Hilcorp's request NMFS removed
the renewal provision from these IHAs.
Comment 18: CBD commented that NMFS' interpretation of ``small'' as
it pertains to the small numbers analysis is unreasonable, and that a
number may be considered small only if it is ``little or close to
zero'' or ``limited in degree.''
Response: In NMFS' Final Rule for taking of marine mammals
incidental to geophysical surveys in the Gulf of Mexico (86 FR 5322,
January 19, 2021), NMFS fully describes its interpretation and
implementation of ``small numbers''. Included as part of that
discussion, NMFS explains the concept of ``small numbers'' in
recognition that there could also be quantities of individuals taken
that would correspond with ``medium'' and ``large'' numbers. As such,
NMFS has established that one-third of the most appropriate population
abundance number--as compared with the assumed number of individuals
taken--is an appropriate limit with regard to ``small numbers.'' This
relative approach is consistent with the statement from the legislative
history that ``[small numbers] is not capable of being expressed in
absolute numerical limits'' (H.R. Rep. No. 97-228, at 19 (September 16,
1981)), and relevant case law (Center for Biological Diversity v.
Salazar, 695 F.3d 893, 907 (9th Cir. 2012) (holding that the U.S. Fish
and Wildlife Service reasonably interpreted ``small numbers'' by
analyzing take in relative or proportional terms)).
We note that the comment selectively includes a definition in
support of CBD's favored position. For example, the definition of
``small'' in Webster's New Collegiate Dictionary (1981) included
``having little size, esp. as compared with other similar things.'' See
also <a href="http://www.merriam-webster.com/dictionary/">www.merriam-webster.com/dictionary/</a> small (defining ``small'' as
``having comparatively little size''). These definitions comport with
the small numbers interpretation developed by NMFS, which utilizes a
proportionality approach.
Comment 19: CBD claims that NMFS's proposed IHAs failed to account
for all sources of take.
Response: NMFS acknowledges that Hilcorp's overall activity in Cook
Inlet
[[Page 62373]]
includes more than the activities for which take is authorized under
these IHAs. Firstly, ITAs under the MMPA are a request-based
authorization by which NMFS analyzes the potential for incidental
harassment at the request of the applicant for the activities
described. NMFS also considers other related activities by the
applicant to assess whether they, alone or in combination with the
specified activity for which take was requested, may result in take,
and will advise if they should be included in the take application. In
the specific example used by CBD that vessel trips may increase by two
trips per day from normal platform operations, there is no indication
that take is likely to occur nor has Hilcorp requested take due to
supply vessel trips. While vessel noise can contribute to masking and
is a contributor to elevated noise in the area, the manner in which
Hilcorp plans to operate their support vessel (with inherent mitigation
to avoid the presence of marine mammals) supports the assessment that
an encounter with a marine mammal, let alone a disruption of their
behavioral pattern, is unlikely to occur.
Comment 20: CBD commented that NMFS failed to consider noise from
water jets, production drilling, helicopters, and vessel traffic.
Response: NMFS considered these additional sources and did not find
authorization of take was warranted for these activities. Additional
detail about these sources and NMFS' rationale is provided in the
Detailed Description of Specific Activity section of this notice.
NMFS also disagrees with CBD's characterization that the MMPA
definition of harassment ``includes not only those activities that will
or are likely to cause take but those that `ha[ve] the potential to
injure . . . or . . . disturb a marine mammal.' '' This is an
incomplete recitation of the statutory definition of harassment. Level
B harassment refers to an act of pursuit, torment, or annoyance that
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.'' This requires that an act have ``the potential to disturb
by causing disruption of behavioral patterns,'' not simply result in a
detectable change in motion or vocalization. See 84 FR 63268, 63285
(December 7, 2018).
Comment 21: CBD commented that NMFS is artificially lowering take
estimates ``by calculating the number of harassments per activity by
days of exposure rather than the instances of harassment.''
Response: In order to provide a practical, consistent, biology-
based (i.e., the Diel Cycle) currency for impact assessment across the
wide range of take calculation methods applicants may use--for years
NMFS has recommended that for the purposes of counting instances of
take--we do not consider one individual as taken more than one time in
a day, even if that an individual could be exposed to sound or other
stressors multiple separate times in one day. For the purposes of the
negligible impact analysis of the effects of the enumerated takes on
any individuals and the stock, though, it is important to understand
the likely nature of these enumerated instances of take (e.g.,
momentary exposure versus multiple hours, high level versus low level),
and that is how the potential for multiple exposures in a day (if
expected) or longer duration exposures are appropriately considered in
the analysis.
For Hilcorp, NMFS used the best available science to arrive at the
most realistic characterization of potential harassment possible. In
this instance, NMFS calculated the area likely to be ensonified above
120 dB and applied the best available density values for species in
Cook Inlet to arrive at a number of individuals exposed in a single
day. This is then multiplied by the number of days to result in the
number of exposures across the entire duration of the activity (e.g.,
14 or 16 days, respectively). If anything, this calculation may be an
overestimate as animals are not uniformly distributed across the action
area, and the same individual animals may be exposed to sound levels
greater than 120 dB several times over the duration of the activity but
due to the constraints of our calculations, they are being considered
as separate animals in our estimations.
Comment 22: CBD commented that NMFS' small numbers determination
for Cook Inlet beluga whales fails to consider the status of the
species. CBD claims that ``small'' must be considered against the
status of the species and whether the percentage of take for each
affected species will ensure that population levels are maintained at
or restored to heathy numbers.
Response: NMFS disagrees with CBD's assertion. The argument to
establish a small numbers threshold on the basis of stock-specific
context is unnecessarily duplicative of the required negligible impact
finding, in which relevant biological and contextual factors are
considered in conjunction with the amount of take and would risk
conflating the two standards. Similarly, CBD's assertion that NMFS'
small numbers analysis must consider whether the percentage of take
would restore a population to ``healthy number'' is not required by
section 101(a)(5)(D) of the MMPA.
Comment 23: CBD commented that NMFS has no basis on which to
conclude that additional harassment by noise has a negligible impact on
Cook Inlet beluga whales as a species, given the population's lack of
recovery and continued decline.
Response: In the Negligible Impact Analysis and Determination
section, we describe how the take predicted and authorized for
Hilcorp's tugboat activity (not additional harassment by noise at
large), which is 11 in Year 1 and 22 in Year 2 for beluga whales, will
have a negligible impact on all of the affected species. In summary,
this determination is based upon the small numbers of beluga whales
that might be exposed briefly during the 16 days of the activity, the
comparatively low degree of behavioral harassment that might result
from any one of the 11 or 22 instances of take that occur within a
year, and the likelihood that the mitigation measures further lessen
the likelihood of exposures. NMFS has considered the status and decline
of Cook Inlet beluga whales in its analysis, as well as the importance
of reducing impacts from anthropogenic noise, but nonetheless, there is
no indication that brief exposure to low level noise not causing
greater than Level B harassment would have a greater than negligible
impact on Cook Inlet beluga whales.
Comment 24: CBD claims that NMFS incorrectly stated that Cook Inlet
beluga whales are not known to engage in critical behaviors in the area
where Hilcorp's project is planned.
Response: NMFS acknowledges observation of one potential but
unconfirmed incidence of mating behavior in the Trading Bay area, but
the extent to which critical behaviors occur in Hilcorp's project area
is still unknown. (Lomac-Macnair et al., 2016). Such behaviors have not
been reported since. Surveys by NMFS or McGuire et al. (2020) with
concentrated effort on the western coast of Cook Inlet have not yielded
a comparable sighting. Other key behaviors, such as calving and
feeding, are described in more detail below but are thought to occur
primarily in other concentrated areas outside of Hilcorp's action area.
We are unaware of any information regarding areas where Cook Inlet
belugas are more likely to engage in mating behavior, however, what is
known about calving suggests that it is
[[Page 62374]]
most concentrated in the upper Inlet, north of Hilcorp's project area.
McGuire et al. (2020) characterizes habitat use by age class in
northern Cook Inlet and documented the majority of calves in the
northernmost parts of Cook Inlet (e.g., Susitna Delta) despite
concentrated survey effort in areas along the west part of the Inlet
heading south toward the Forelands. NMFS acknowledges that Cook Inlet
beluga whales use the area, especially in spring and fall months, but
their habitat range at those times is not nearly as constricted as
their summer habitat, which is concentrated in a small area with high
anthropogenic activity.
Cook Inlet beluga whales may well occur in the project area, which
is why a small amount of take by Level B harassment is authorized for
this species incidental to Hilcorp's jack-up rig towing. Tagging data,
acoustic studies, and opportunistic sightings indicate that Cook Inlet
belugas continue to occur in the upper inlet throughout the winter
months, in particular the coastal areas from Trading Bay to Little
Susitna River, with foraging behavior detected in lower Knik Arm and
Chickaloon Bay, and also detected in several areas of the lower inlet
such as the Kenai River, Tuxedni Bay, Big River, and NW Kalgin Island
(Castellote et al., 2011, 2020, 2021; C. Garner, pers. comm.; Shelden
et al., 2015, 2018). Belugas were historically seen in and around the
Kenai and Kasilof rivers during June aerial surveys conducted by ADFG
in the late 1970s and early 1980s and by NMFS starting in 1993 (Shelden
et al., 2015b), and throughout the summer by other researchers and
local observers. In recent years, sightings in and near these rivers
have been more typical in the spring and fall (Ovitz, 2019). It is
unknown if this is due to increased monitoring efforts in the area or
an increase in belugas using this area. While visual sightings indicate
peaks in spring and fall, acoustic detections indicate that belugas can
be present in the Kenai River throughout the winter (Castellote et al.,
2016). Despite the historic sightings (1970s-1990s) of belugas
throughout the summer (June-August) in the area, recent acoustic
detections and visual sightings indicate that there appears to be a
steep decline in beluga presence in the Kenai River during the summer,
despite an annual return in recent years of 1-1.8 million sockeye
salmon, which are important beluga prey.
As described above, we have no reason to expect beluga whales to be
concentrated in the path of Hilcorp's tug boats for the purposes of
reproductive or feeding behaviors, but even if one or more of the 11
(Year 1) or 22 (Year 2) instances in which the brief tugboat operations
intersects with an individual beluga is engaged in these behaviors, the
anticipated short duration and low level disturbance of any such
encounter would not be likely to impact reproductive or foraging
success of any individuals.
Comment 25: CBD comments that NMFS' negligible impact determination
relies largely on mitigation measures required under the IHAs that
require visual observations, which it claims are ineffective.
Response: NMFS disagrees with this characterization of the
negligible impact determination. Our discussion in the Negligible
Impact Analysis and Determination section below contains the factors
NMFS considered in reaching its negligible impact determinations.
Although NMFS' implementing regulations at 50 CFR 216.104 (c) state
that NMFS may incorporate successful implementation of mitigation
measures to arrive at a negligible impact determination, for issuance
of IHAs for Hilcorp's tug towing rig activity, NMFS did rely upon an
assumption of set level of effectiveness in mitigation to make our
negligible impact determinations. That said, based on prior monitoring
efforts in Cook Inlet, it is clearly possible to detect and identify
marine mammals to the species level at kilometers away from the source
level, including beluga whales. This is dependent on several factors
such as visual acuity, sea state, glare, animal behavior/body type,
speed of travel for vessel and animal, etc.. NMFS does not assume total
effectiveness of monitoring, but the demonstrated record of protected
species observer sightings for activities in Cook Inlet illustrate that
visual monitoring is appropriate for implementing mitigation such as
avoidance in this case.
Comment 26: CBD commented that NMFS relied on Hilcorp's commitment
to operate with the favorable tide to reduce the power output of the
tugs without including the requirement in the IHAs.
Response: The requirement to use a favorable tide and operate at
night if a favorable tide fell during nighttime hours was included in
the Proposed IHAs Year 1 and Year 2 that were available on our website
(<a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llc-oil-and-gas-activities-cook-inlet-alaska-0">https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llc-oil-and-gas-activities-cook-inlet-alaska-0</a>) as
measures 4.f and 4.g. It is also in the final IHAs.
Comment 27: CBD commented that NMFS failed to ensure the least
practicable adverse impact on Cook Inlet beluga whales by failing to
consider requiring the use of passive acoustic monitors to detect the
presence of marine mammals.
Response: NMFS considered the use of passive acoustic monitoring
for mitigation purposes in the rulemaking for Hilcorp's oil and gas
activities in Cook Inlet. As we stated in the notice of proposed
rulemaking, passive acoustic monitoring for previous activities in Cook
Inlet where incidental take was authorized by NMFS has not been an
effective mitigation or monitoring measure due to environmental
conditions (84 FR 12330, 12368; April 1, 2019 (incorporating by
reference discussion of limited effectiveness of passive acoustic
monitoring for survey mitigation in Hilcorp's petition for
rulemaking)). For the same reasons, we have determined passive acoustic
monitoring is not likely to be sufficiently effective at detection for
real-time mitigation for Hilcorp's tug towing activities and is not
included in the IHAs.
As CBD notes, academic researchers have begun to implement more
effective passive acoustic monitors for research purposes at several
places in Cook Inlet (Castellote et al., 2020). However, the framework
used by those researchers is impractical, particularly for Hilcorp's
planned activity, which primarily involves straight-line transit. An
article on NOAA's website (<a href="https://www.fisheries.noaa.gov/science-blog/beluga-whale-acoustic-monitoring-survey-post-3">https://www.fisheries.noaa.gov/science-blog/beluga-whale-acoustic-monitoring-survey-post-3</a>) clearly illustrates the
level of customization, expertise, and difficulty required to assemble
a passive acoustic mooring to then deploy in the Inlet. Additionally,
these instruments are stationary, which means to effectively use these
monitors as a means of avoiding harassment of marine mammals during
Hilcorp's activity, Hilcorp would need to build and successfully deploy
dozens (or more) of stationary monitors along a route of travel that is
subject to change depending upon weather or other environmental and
shipping restrictions. Additionally, the data stored on these types of
moorings is not accessible until they are retrieved by the researcher
who deployed them. In the future, if an established network of passive
acoustic monitors with shared access to the data is available, this
could be a useful tool for implementing mitigation measures, but is
currently not practicable.
Comment 28: CBD commented that NMFS failed to consider time-area
restrictions for tugs such as Trading Bay in April and May and a
prohibition on
[[Page 62375]]
activities from July through September (CBD did not specify a location
for this proposed measure).
Response: NMFS did consider such a time-area restriction and does
not agree that these proposed restrictions are appropriate under the
least practicable adverse impact standard. Hilcorp's activity in
Trading Bay would be either a single day of transit or several hours of
positioning the jack-up rig at an existing well site. As discussed in
our above comment response, there has been one published observation of
potential (not confirmed) mating behavior of Cook Inlet beluga whales
in Trading Bay. Surveys by NMFS or McGuire et al. with concentrated
effort on the western coast of Cook Inlet have not yielded a comparable
sighting. Closure of the entire area for two months is not practicable
as Hilcorp would not be able to access the well sites that are part of
the intended activity. As discussed above and in the species-specific
section of the proposed IHAs, Cook Inlet belugas are highly
concentrated in the upper Cook Inlet especially in the summer months
(Goetz et al., 2012; McGuire et al., 2020). In the past, Cook Inlet
beluga whales used the Kenai area in summer months but that trend has
shifted in recent decades to occasional spring and fall sightings
(Ovitz, 2019). Throughout the Inlet, mean group sizes during the summer
and fall were largest in July and smallest in October, with the largest
groups seen during mid-July and early August in the Susitna River
Delta, while the smallest group sizes were in the Kenai River Delta.
These patterns of high seasonal concentrations have continued to be
documented since 2012 (e.g., McGuire et al., 2020). In reflection of
this information, NMFS has imposed time area restrictions in the
Susitna River Delta from April to November to reduce effects of
Hilcorp's activity to the greatest extent practicable. In the case of
the Tyonek platform, which lies within 10 miles of the mean lower-low
water line of the Little Susitna and Beluga Rivers, Hilcorp will
conduct aerial surveys to clear the Tyonek platform of Cook Inlet
beluga whales to the greatest extent practicable. This evidence further
suggests a closure in the middle Inlet during the summer months, in the
season with longest daylight hours and best conditions for visual
observations to implement mitigation and monitoring, is not appropriate
under the least practicable adverse impact standard.
See also response to comment 24.
Comment 29: CBD stated that NMFS failed to consider noise-quieting
engines such as electric tugboats.
Response: The citation provided by CBD regarding electric tugboats
was a link to a concept drawing of a boat that is not expected to be on
the seas in the U.S. until at least 2023. NMFS is not aware of any
commercially available seaworthy tug vessels that are used in tandem
(e.g., three tug configuration) with effective quieting technologies or
of any company or entity with electric tug fleets able to use them in
tandem as required for Hilcorp's activities.
Comment 30: CBD commented that NMFS did not meaningfully consider
the chosen clearance zone distance of 1,500 meters and that it is not
equivalent to the Level B harassment zone.
Response: CBD is correct that the clearance zone required under the
IHAs (1,500 m) is not equivalent to the Level B harassment zone (3,850
m). There is no requirement that the clearance zone be equal to or
greater than the Level B harassment zone. Using the Level B harassment
zone as the clearance zone would be impractical as identification of
certain species may be unreliable at such distance in Cook Inlet's
environmental conditions. The 1,500 m distance ensures more effective
monitoring closest to the vessels, where any potential impact to
animals is anticipated to be the greatest. While underway, protected
species observers will observe for marine mammals to the greatest
extent possible (and they are not limited to observing within 1,500 m
of the vessel). Any marine mammal sighted by PSOs at any distance is
noted and reported to NMFS, per the reporting requirements of the IHAs.
Comment 31: CBD comments that NMFS defines its purpose and need in
the Environmental Assessment too narrowly, making issuance of
successive IHAs the only option.
Response: NMFS disagrees with this characterization of purpose and
need. Under section 101(a)(5)(D) of the MMPA, NMFS has an obligation to
consider and grant requests for the taking of marine mammals incidental
to a specified activity, provided they satisfy the relevant
requirements. Hilcorp submitted an application for two IHAs, each
covering 1 year of tug towing rig activity. Once deemed adequate and
complete, NMFS had an obligation to consider and respond to these
requests in the manner described in the implementing regulations. While
Hilcorp's request for two IHAs did not guarantee that they would be
issued (i.e., if one or both years of the specified activity did not
satisfy the relevant MMPA standards, NMFS would not issue the IHA(s)),
characterizing the purpose and need to include issuance of only one IHA
would not be in accordance with our requirement to consider both
adequate and complete requests submitted by Hilcorp.
Comment 32: CBD commented that NMFS segmented its analysis of the
impacts of Hilcorp's activities under these IHAs from the activities
authorized under the ITRs.
Response: As explained earlier (see Comment 1), NMFS is in the
process of withdrawing the ITRs based on Hilcorp's representations that
they will not be undertaking any further activities for which take was
authorized under the ITR during the remaining period of effectiveness.
The only take currently authorized by NMFS incidental to Hilcorp's
activities in Cook Inlet, Alaska, over the next 2 years is through the
two IHAs for the take incidental to tugs towing the jack-up rig, as
described in this notice.
Comment 33: CBD commented that NMFS failed to consider several
additional alternatives under NEPA including: requiring the use of
passive acoustic monitoring to detect the presence of marine mammals;
requiring the use of drones to detect the presence of marine mammals;
requiring the use of electric tugboats; restrictions on the timing of
activities when Cook Inlet belugas are less likely to be present;
restrictions on the overall amount of authorized activity, and
authorizing take incidental to decommissioning activity but not
production activity.
Response: Under NEPA, NMFS is required to consider a reasonable
range of alternatives. Our EA considered the preferred alternative,
which satisfied our purpose and need, and the no-action alternative. We
also considered, but rejected from further consideration, two
variations of the preferred alternative, including alternative
technologies (such as electric tugboats). Similarly, as explained in a
previous response, NMFS is not requiring mitigation such as passive
acoustic monitoring or electric tugboats because they do not satisfy
the MMPA's least practicable adverse impact standard. NMFS is requiring
a time-area closure specifically to enhance protection for Cook Inlet
beluga whales based on the best available science. This mitigation
measure to protect Cook Inlet beluga whales in a biologically important
area at times of known high density of whales was included in the
preferred alternative. NMFS did not explore ``restrictions on the
overall amount of authorized activity'' because NMFS does not authorize
the underlying activity, and restricting the amount would have changed
the applicant's specified activity (and further was not necessary
[[Page 62376]]
to reach our negligible impact determinations). NMFS did not consider
authorizing take incidental to decommissioning (P&A) activity but not
production activity because for purposes of our MMPA analyses of the
impacts of the tug activities, these are exactly the same activity--the
same three tugboats pulling and positioning one jack-up rig for the
time windows provided in the project description. NMFS is not
authorizing any take of marine mammals incidental to production
drilling itself or decommissioning itself, but rather the moving of the
jack-up rig into position, which will then be used to complete those
activities. Authorizing take incidental to tugs towing the jack-up rig
to be used only for decommissioning purposes would be arbitrary and
capricious.
Comment 34: CBD commented that NMFS' EA failed to consider impacts
from vessels and other sources associated with Hilcorp's activity, even
if they do not rise to the level of take.
Response: NMFS disagrees with this characterization. In the
description of the activity in NMFS' EA, as in the Federal Register
notice of proposed IHAs, NMFS includes a discussion of other activity
associated with Hilcorp's rig-towing and why it does not rise to the
level of take. NMFS has included that discussion in this Federal
Register notice as well with further detail about the way Hilcorp plans
to conduct those activities that means take is unlikely. Aspects of
these sources, such as increased vessel traffic or helicopter traffic
to the area, are addressed in the EA in the Cumulative Effects section.
Comment 35: CBD commented that NMFS' EA relies on mitigation
measures required in the IHAs to dismiss the significance of impacts
from Hilcorp's activity, claiming that the mitigation measures rely on
marine mammals being detected by observers which CBD considers
ineffective. CBD did not provide any examples or citations of this in
their description.
Response: NMFS does not rely on ineffective mitigation measures to
dismiss the significance of impacts--as described in the EA, the
primary reason the impacts are considered insignificant are because of
the limited duration of the activity (14 and 16 days respectively), the
low level of noise created by the tug configuration, and the low
density of marine mammals in the action area resulting in small
exposure estimates. Further, NMFS disagrees with the characterization
that the mitigation measures are ``ineffective'' because they rely on
visual detection. NMFS has received many marine mammal monitoring
reports over the years demonstrating that visual observers for marine
mammals are effective in Cook Inlet. At no point in the MMPA or NEPA
analysis does NMFS assume that mitigation is 100 percent effective, as
environmental conditions can confound monitoring effort, but there is a
spectrum of effectiveness when implementing mitigation, and visual
observation in Cook Inlet is an appropriate means for detecting marine
mammals to implement mitigation zones.
Comment 36: CBD comments that NMFS' EA fails to properly analyze
the current state of climate change and how new fossil fuel production
contributes to climate change. CBD claims that NMFS must consider and
disclose how facilitating fossil fuel production and total greenhouse
gas emissions associated with the project will exacerbate climate
change. As part of this analysis, CBD contends that NMFS must consider
downstream greenhouse gas emissions.
Response: NMFS considers climate change in its EA. However, as
described previously, NMFS does not authorize production drilling or
any of Hilcorp's activities but rather take of marine mammals
incidental to Hilcorp's activities. In Federal waters, BOEM conducts
lease sales that provide qualified bidders the opportunity to bid on
blocks of the outer continental shelf to gain conditional rights to
explore, develop, and produce oil and natural gas in those blocks.
BOEM's consideration of climate change for its lease sales is found in
the agency's environmental compliance documents, such as the EIS
written for Lease Sale 244 (BOEM, 2016), the most recent lease sale in
Cook Inlet, Alaska. Of note, for Alaska state waters, Hilcorp would
obtain necessary permits for production drilling from Alaska Department
of Environmental Conservation. NMFS' IHAs cover take of marine mammals
incidental to tugs towing and positioning a jack-up rig, which may
occur even if Hilcorp produces no natural gas or oil from their wells
with the jack-up rig.
Comment 37: CBD commented that NMFS failed to properly consider
impacts to subsistence use as Hilcorp's activity would impede the
recovery of Cook Inlet beluga whales, which in turn affects the beluga
harvest.
Response: NMFS considered impacts on subsistence users, especially
for species such as harbor seals, which are harvested by communities
along Cook Inlet. NMFS found that take of Cook Inlet beluga whales
incidental to Hilcorp's tug towing activity would have a negligible
impact on the stock and there is no evidence to suggest that the
impacts of 14 or 16 days of rig towing per year for 2 years (resulting
in 11 and 22 low-level behavioral disturbance events, respectively),
would impact the reproductive success or survival of any individual in
any way, much less impede the recovery or impact the availability of
Cook Inlet beluga whales for subsistence harvest were a harvest to
occur.
Comment 38: CBD also commented that NMFS failed to take a hard look
at cumulative impacts of the IHAs, specifically with respect to Cook
Inlet beluga whales.
Response: NMFS disagrees with the assertion that cumulative impacts
were not adequately considered, especially with respect to Cook Inlet
beluga whales. Cook Inlet beluga whales are frequently discussed
together with the other 11 species of marine mammal for which take is
authorized, as cited in CBD's example regarding vessel noise, because
effects of vessel noise on Cook Inlet beluga whales are expected to be
highly similar to the effects of vessel noise on other marine mammals,
except in that the number of takes is different (and lower) than some
other species due to their likely distribution in the area. As
described in Castellote et al. (2019), Cook Inlet beluga whales are one
of the species that exhibits high site fidelity with a strong temporal
correlation. Because of this, there is strong evidence that Cook Inlet
beluga whales are not expected to occur in the project area during the
ice-free season when Hilcorp would be towing the rigs in a largely
offshore environment. While Cook Inlet beluga whales exhibit high site
fidelity, it is not fidelity to the project area at the time of year
and location of Hilcorp's platforms. They may be affected by other
activities in the area where they would be expected to occur in ice-
free seasons, such as the Port of Anchorage, and those activities are
discussed in our Cumulative Effects section of the EA.
Cumulative impacts have been adequately addressed under NEPA in the
final environmental assessment (EA) supporting NMFS' determination. In
the final EA, we reviewed potential direct, indirect, and cumulative
impacts to protected species and their environment, associated with
NMFS' proposed action and alternatives. Separately, cumulative effects
were analyzed as required through NMFS' required intra-agency
consultation under section 7 of the ESA. The Biological Opinion (BiOp)
that NMFS Alaska Region issued on September 9, 2022, determined that
NMFS' action of issuing the IHAs is not likely to
[[Page 62377]]
jeopardize the continued existence of listed marine mammals or result
in the destruction or adverse modification of critical habitat of such
species, including Cook Inlet beluga whales.
Comment 39: CBD commented that NMFS' cumulative impacts analysis
ignores the impacts of take of Cook Inlet beluga whales already
authorized or occurring, including take from other ITAs, research
permits, and unpermitted takes from vessel noise, water pollution, and
other impacts. Further, CBD commented that NMFS should attempt to
quantify take and analyze impacts to the species in the EA.
Response: NMFS agrees with CBD that a quantification of take may be
helpful to the public and has included those numbers in the appropriate
section of the EA's cumulative effects discussion. However, these take
numbers are frequently taken out of context when purely summed. Takes
of marine mammals, including Cook Inlet beluga whales, through other
ITAs is considered in NMFS' environmental baseline when conducting the
necessary analysis for issuance of these IHAs. There are other takes of
Cook Inlet beluga whales authorized for scientific research and
enhancement of the species. While they are all considered ``take'' for
purposes of issuing an authorization or permit under the MMPA in
advance of an activity, the context of these takes is important (see
responses to Comments 13 and 14). Authorized takes, in the research
context, are what allow researchers frequently cited by NMFS and CBD
(e.g., Castellote et al., McGuire et al., Shelden et al., Hobbs et al.)
to collect the scientific data necessary to inform their publications.
Researchers' interactions with marine mammals are carefully controlled
through permit conditions and reporting requirements, which often
require research efforts to cease if any effects to important
biological functions are detected by qualified researchers that are
skilled at observing marine mammal behavior (NMFS, 2019).
The context of the take is of the utmost importance when
cumulatively evaluating takes of marine mammals, as the intensity of
impacts from a given activity can vary widely. For example, an animal
exposed to noise levels just above our harassment threshold in a non-
critical area may experience a small change in a behavioral pattern
with no biological consequence while an animal exposed to very loud
noise levels in an area where active critical foraging occurs could
result in behavioral changes that may be more likely to impact fitness.
While both of these examples would be characterized as Level B
harassment, the resulting impact on the population could be different.
Context differences such as these are analyzed in our negligible impact
analysis for each application under the MMPA.
Furthermore, NMFS does not consider unpermitted ``takes''
explicitly in its analysis. It is difficult to determine if a take has
occurred without monitoring in place to assess the effects of a
particular activity. However, NMFS broadly and qualitatively addresses
potential effects from other types of activity or development without
distinguishing if any potential ``take'' is permitted. For example,
NMFS considers potential effects of construction activities, some of
which have the potential to result in take, in the Cumulative Effects
section of the EA. NMFS discusses the overall effects of construction
without discerning individual takes due to construction or attributing
takes to a ``permitted'' or ``unpermitted'' status.
Comment 40: CBD commented that NMFS failed to consider Hilcorp's
poor track record of environmental and safety violations and accidents
and how this may affect the environmental impacts of Hilcorp's
activities under the IHAs.
Response: Oil spills, accidents, or other disasters stemming from
man-made structures in Cook Inlet are not considered, as they are not
authorized and are a breach of authorizations and perhaps of other
agencies' regulations. It is the responsibility of the applicants to
comply with all additional regulations, and to work with the state to
obtain approval of their Oil Discharge Prevention and Contingency Plans
(ODPCP).
Comment 41: CBD commented that NMFS should reinitiate and complete
consultation on the 5-year take regulations and issue a biological
opinion that properly analyzes the impacts of all of Hilcorp's
activities on threatened and endangered species and their habitats,
including from tugs towing rigs.
Response: As described above, NMFS is in the process of withdrawing
the incidental take regulations issued to Hilcorp in 2019, as none of
the activity for which incidental take was authorized is planned to
occur in the foreseeable future. The remaining take of marine mammals
incidental to Hilcorp's activity is solely from Hilcorp's tug-towing
activities, which are covered by these IHAs and for which consultation
was completed. The resulting Biological Opinion was issued on September
9, 2022.
Changes From Proposed IHAs to Final IHAs
There are several changes from the proposed IHAs, starting with the
timing of the activity. The Year 1 and Year 2 IHAs were initially
proposed to become effective in April 2022 and April 2023,
respectively. This timeline has been delayed during the course of
processing the IHA requests. Hilcorp now requests that the Year 1 IHA
be effective September 2022 and the Year 2 IHA become effective on
September 2023. Since the conclusion of the public comment period in
June 2022, NMFS has reviewed newly available information, including
recent draft Stock Assessment Reports, information on relevant Unusual
Mortality Events, and other scientific literature, and incorporated
this information into our analysis of impacts on marine mammals and
their habitat. Additionally, NMFS removed the consideration of renewals
of the IHAs at Hilcorp's request.
During the processing of the IHA requests, Hilcorp notified NMFS of
the need to conduct the initial rig tow in June 2022. On April 28,
2022, Hilcorp sent a letter to NMFS describing the need to move the
jack-up rig as well as the mitigation and monitoring Hilcorp planned to
employ during the rig move to avoid take. In a letter dated May 17,
2022, in consideration of the low likelihood of exposures above the 120
dB harassment threshold, the short duration of the jack-up rig move,
the further reduced likelihood of exposure above 120 dB supported by
the expanded mitigation, and further, the reduced probability that an
animal exposed to a received level above 120 dB tugboat noise would
respond in a manner that qualifies as a take under the MMPA, NMFS
concurred with Hilcorp's assessment that take of marine mammals by
Level B harassment is unlikely to occur during the transport of the
jack-up rig from the Rig Tender's Dock in Nikiski to the Tyonek
platform in middle Cook Inlet. NMFS' concurrence letter did not
authorize any take of marine mammals under the MMPA or ESA incidental
to the rig move. As a result of this initial move, Hilcorp's planned
Year 1 activities have been reduced to approximately 14 days of tug
towing and positioning. This reduction in activity duration under the
IHA, and appropriate reductions in take estimates, have been made
throughout this notice and the Year 1 IHA.
Hilcorp began the mobilization process in June 2022 as described in
their April 28, 2022, letter and fully abided by all of the
minimization measures described therein. Three
[[Page 62378]]
ocean-going tugs towed the jack-up rig for 32.2 miles and the
approximate total time under load including transiting, holding and
positioning amounted to 27 hours. The jack-up rig was positioned at the
Tyonek platform where it has remained since that mobilization. During
the rig move, Hilcorp observed 14 harbor porpoises and six harbor seals
at distances ranging from 75 meters to 4,960 meters from the tug towing
jack-up rig configuration, and no beluga whales. Based on the distance
at which some animals were observed and our assumed source levels, it
is possible individual animals received sound levels greater than 120
dB, which is NMFS' current threshold for estimating when Level B
harassment is predicted to occur, though there are other qualitative
factors that may be considered. There are certain characteristics of
tugging that reduce the probability that being exposed to received
levels above 120 dB will result in disruption of behavioral patterns.
Tugboats under load, especially a multi-tug configuration, are slow-
moving as compared to typical recreational and commercial vessel
traffic. Assuming an animal was stationary, exposure from the moving
tug configuration would be on the order of minutes in any particular
location. Hilcorp's monitoring report indicates these animals were
traveling or swimming, with three animals changing their course of
direction when approaching the tug configuration, suggesting their
exposure time could have been even shorter. The slow, predictable, and
generally straight path of this tug configuration further lessened the
likelihood that exposures at the expected levels resulted in the
harassment of marine mammals. The slow transit along a predictable path
occurred in an area of routine vessel traffic where many large vessels
move in slow straight-line paths, and some individuals are expected to
be habituated to these sorts of exposures.
NMFS made two changes with respect to species and stocks included
in the final IHAs. During the course of consultation under the ESA, it
was brought to NMFS' attention that humpback whales in Cook Inlet could
potentially belong to the Western North Pacific stock as well as the
Central North Pacific stock. NMFS has considered both stocks in our
analysis for the final IHAs. Additionally, BOEM suggested that Pacific
white-sided dolphins be included based on acoustic detection data. They
have been included in our analysis and take authorized in the final
IHAs.
During the process of section 7 consultation under the ESA, Hilcorp
notified NMFS that complying with the Susitna Delta mitigation zone as
proposed would not be practicable for operations at their Tyonek
platform because the location of the platform is within the Susitna
Delta exclusion zone. The dates and applicability of the Susitna Delta
exclusion zone have been changed from the proposed to final IHAs. The
changes, as well as additional protective measures associated with the
change, are described in more detail in the Mitigation section below.
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.
Additional information regarding population trends and threats may be
found in NMFS's 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's
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 4 lists all species or stocks for which take is expected and
authorized for this action, 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. For taxonomy, we follow the Committee on Taxonomy (2021).
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's SARs). While no
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 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's 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's U.S. 2021 SARs (e.g., Muto et al., 2022). All values presented
in Table 4 are the most recent available at the time of publication and
are available in the 2021 SARs (Muto et al. 2022) (available online at:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>).
Table 4--Marine Mammal Species or Stocks for Which Take Is Expected and Authorized
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray whale...................... Eschrichtius robustus.. Eastern North Pacific.. -, -, N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenidae:
Humpback whale.................. Megaptera novaeangliae. Western North Pacific.. E, D, Y 1,107 (0.3, 865, 2006) 3 2.8
Humpback whale.................. Megaptera novaeangliae. Central North Pacific.. E, D, Y 10,103 (0.3, 7,890, 83 26
2006).
Minke whale..................... Balaenoptera Alaska................. -, -, N N/A (see SAR, N/A, see UND 0
acutorostrata. SAR).
Family Balaenopteridae (rorquals):
Fin whale....................... Balaenoptera physalus.. Northeast Pacific...... E, D, Y see SAR (see SAR, see see SAR 0.6
SAR, 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 62379]]
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Beluga whale.................... Delphinapterus leucas.. Cook Inlet............. E, D, Y 279 (0.061, 267, 2018) 0.53 0
Killer whale.................... Orcinus orca........... Alaska Resident........ -, -, N 2,347 c (N/A, 2347, 24 1
2012).
Killer whale.................... Orcinus orca........... Gulf of Alaska, -, -, N 587 c (N/A, 587, 2012) 5.87 0.8
Aleutian Islands, and
Bering Sea Transient.
Pacific white-sided dolphin..... Lagenorhynchus North Pacific.......... -, -, N 26,880 (N/A, unknown, UND 0
obliquidens. 1998).
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Alaska......... -, -, Y 31,046 (0.21, N/A, UND 72
1998).
Dall's porpoise................. Phocoenoides dalli..... Alaska................. -, -, N see SAR (0.097, see 131 37
SAR, 2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
Steller sea lion................ Eumetopias jubatus..... Western................ E, D, Y 52,932 a (see SAR, 318 254
52,932, 2019).
California sea lion............. Zalophus californianus. U.S.................... -, -, N 257,606 (N/A, 233,515, 14,011 >320
2014).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Cook Inlet/Shelikof.... -, -, N 28,411 (see SAR, 807 107
26,907, 2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="http://www.nmfs.noaa.gov/pr/sars/">www.nmfs.noaa.gov/pr/sars/</a>. CV is coefficient of variation; Nmin is the minimum estimate of
stock abundance. In some cases, CV is not applicable depending on the methodology described in the stock assessment report (SAR) and the date of last
available survey data. Where necessary, NMFS refers reader to the SAR for more detail.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual mortality and serious injury often cannot be determined precisely and is in some cases presented as a
minimum value or range.
As indicated above, all 12 species (with 14 managed stocks) in
Table 4 temporally and spatially co-occur with the activity to the
degree that take could reasonably occur, and we have authorized it. In
addition, the northern sea otter may be found in Cook Inlet, Alaska.
However, sea otters are managed by the U.S. Fish and Wildlife Service
and are not considered further in this document.
Pacific White-Sided Dolphin
Pacific white-sided dolphins are a pelagic species. They are found
throughout the temperate North Pacific Ocean, north of the coasts of
Japan and Baja California, Mexico (Muto et al., 2018). They are most
common between the latitudes of 38[deg] North and 47[deg] North (from
California to Washington). The distribution and abundance of Pacific
white-sided dolphins may be affected by large-scale oceanographic
occurrences, such as El Ni[ntilde]o, and by underwater acoustic
deterrent devices (NPS, 2018a).
Scientific studies and data are lacking relative to the presence or
abundance of Pacific white-sided dolphins in or near Cook Inlet,
Alaska. Most observations of Pacific white-sided dolphins occur off the
outer coast or in inland waterways near entrances to the open ocean. A
report of acoustic monitoring efforts during Hilcorp's 3D seismic
survey in 2020 concluded that Pacific white-sided dolphins were briefly
detected near Iniskin Bay in Cook Inlet. Detections of vocalizations
typically lasted on the order of minutes, suggesting the animals did
not remain in the area and/or continue vocalizing for extended
durations. These observational data, combined with anecdotal
information, indicate that there is a small potential for Pacific
white-sided dolphins to occur in the Project area. On May 7, 2014,
Apache Alaska observed three Pacific white-sided dolphins during an
aerial survey near Kenai. This is one of the only recorded visual
observations of Pacific white-sided dolphins in Cook Inlet; they have
not been reported in groups as large as those estimated in other parts
of Alaska (e.g., 92 animals in NMFS' IHAs for Tongass Narrows). Due to
the cryptic nature of the species and the lack of maneuverability of
the tug configuration, take of Pacific white-sided dolphins was added
to the proposed authorizations for Year 1 and Year 2.
Humpback whale
Humpback whales are found throughout southern Alaska in a variety
of marine environments, including open-ocean, near-shore waters, and
areas with strong tidal currents (Dahlheim et al., 2009). Most humpback
whales are migratory and spend winters in the breeding grounds off
either Hawaii or Mexico. Humpback whales are regularly present and
feeding in Cook Inlet in the summer. Current threats to humpback whales
include vessel strikes, spills, climate change, and commercial fishing
operations (Muto et al., 2021).
Humpback whales worldwide were designated as ``endangered'' under
the Endangered Species Conservation Act in 1970, and were listed under
the ESA at its inception in 1973. However, on September 8, 2016, NMFS
published a final decision that changed the status of humpback whales
under the ESA (81 FR 62259), effective October 11, 2016. The decision
recognized the existence of 14 distinct population segments (DPSs)
based on distinct breeding areas in tropical and temperate waters. Five
of the 14 DPSs were classified under the ESA (4 endangered and 1
threatened),
[[Page 62380]]
while the other 9 DPSs were delisted. Humpback whales found in the
project area are predominantly members of the Hawaii DPS, which is not
listed under the ESA. However, based on analyses of photo-
identification studies in Alaska, members of the Mexico DPS and the
Western North Pacific DPS, which are listed as threatened and
endangered respectively, are thought to occur in Cook Inlet.
Approximately 1 percent of all humpback whales in Cook Inlet are
thought to belong to the endangered Western North Pacific DPS and 11
percent are thought to belong to the threatened Mexico DPS. All other
humpback whales present are thought to belong to the non-listed Hawaii
DPS (Wade et al., 2021). Members of different DPSs are known to
intermix on feeding grounds; therefore, all waters off the coast of
Alaska should be considered to have ESA-listed humpback whales.
Critical habitat was recently designated near the entrance of lower
Cook Inlet for Western North Pacific DPS and Mexico DPS humpback whales
(86 FR 21082, April 21, 2021); however, Hilcorp's action area does not
spatially overlap with any critical habitat designated for humpback
whale DPS.
The DPSs of humpback whales that were identified through the ESA
listing process do not necessarily equate to the existing MMPA stocks.
The stock delineations of humpback whales under the MMPA are currently
under review. Until this review is complete, NMFS considers humpback
whales in Cook Inlet to primarily be part of the Central North Pacific
stock, with a status of endangered under the ESA and designations of
strategic and depleted under the MMPA (Muto et al., 2021). As described
in the above Changes from Proposed IHAs to Final IHAs, during the
course of consultation under the Endangered Species Act, it was brought
to NMFS' attention that humpback whales in Cook Inlet could
occasionally be from the Western North Pacific stock, and therefore
have been included as a potential stock in the Final IHAs.
In the summer, humpback whales are regularly present and feeding in
the Cook Inlet region, including Shelikof Strait, Kodiak Island bays,
and the Barren Islands, in addition to Gulf of Alaska regions adjacent
to the southeast side of Kodiak Island (especially Albatross Banks),
the Kenai and Alaska peninsulas, Elizabeth Island, as well as south of
the Aleutian Islands. Humpbacks also may be present in some of these
areas throughout autumn (Muto et al., 2017).
Humpback whales have been observed during marine mammal surveys
conducted in Cook Inlet; however, their presence is largely confined to
lower Cook Inlet. During SAExploration's 2015 seismic program, three
humpback whales were observed in Cook Inlet; two near the Forelands and
one in Kachemak Bay (Kendall et al., 2015). During NMFS Cook Inlet
beluga whale aerial surveys from 2000 to 2018, there were 88 sightings
of 191 estimated individual humpback whales in lower Cook Inlet
(Shelden et al., 2017). They have been regularly seen near Kachemak Bay
during the summer months (Rugh et al., 2005). There are observations of
humpback whales as far north as Anchor Point, with recent summer
observations extending to Cape Starichkof (Owl Ridge, 2014). Several
humpback whale sightings occurred lower Cook Inlet between Iniskin
Peninsula and Kachemak Bay near Augustine, Barren, and Elizabeth
Islands (Shelden et al., 2013, 2015, 2017). There were two sightings of
three humpback whales observed near Ladd Landing north of the Forelands
on the recent Harvest Alaska Cook Inlet Pipeline Extension (CIPL)
project (Sitkiewicz et al., 2018). There were 14 sightings of 38
humpback whales observed in the 2019 Hilcorp lower Cook Inlet seismic
survey in the fall (Fairweather Science, 2020). This higher number of
humpback whales was expected in the lower Cook Inlet region than
Hilcorp's proposed work in the late summer/fall period.
Ferguson et al. (2015) identified a biologically important area
(BIA), in which humpback whales are known to concentrate for feeding,
in the Gulf of Alaska region. The BIA encompasses the waters east of
Kodiak Island (the Albatross and Portlock Banks), a target for
historical commercial whalers based out of Port Hobron, Alaska
(Ferguson et al., 2015; Reeves et al., 1985; Witteveen et al., 2007).
This BIA also includes waters along the southeastern side of Shelikof
Strait and in the bays along the northwestern shore of Kodiak Island.
The highest densities of humpback whales around the Kodiak Island BIA
occur from July-August (Ferguson et al., 2015). This BIA lies directly
south but does not spatially overlap with Hilcorp's proposed action
area.
A detailed description of the of the other species likely to be
affected by Hilcorp's tug towing jack-up rig activity, 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 (87 FR 27597, May 9, 2022); 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 5.
[[Page 62381]]
Table 5--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
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 underwater noise from Hilcorp's tug towing jack-up rig activity
has the potential to result in behavioral harassment of marine mammals
in the vicinity of the survey area. The notice of proposed IHA (87 FR
27597, May 9, 2022) included a discussion of the effects of
anthropogenic noise on marine mammals and the potential effects of
underwater noise from Hilcorp's tug towing jack-up rig activity on
marine mammals and their habitat. The effects described in the notice
of proposed IHAs are expected to be the same on Western North Pacific
stock of humpback whales and Pacific white-sided dolphins as for the
other species and stocks considered in the proposed IHAs. 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 (87 FR 27597, May 9, 2022).
Estimated Take
This section provides an estimate of the number of incidental takes
authorized through these IHAs, which informs both NMFS' consideration
of ``small numbers'' and the negligible impact determinations.
Harassment is the only type of take reasonably expected to result
from these activities. Except with respect to certain activities not
pertinent here, section 3(18) of the MMPA defines ``harassment'' as any
act of pursuit, torment, or annoyance, which (i) has the potential to
injure a marine mammal or marine mammal stock in the wild (Level A
harassment); or (ii) has the potential to disturb a marine mammal or
marine mammal stock in the wild by causing disruption of behavioral
patterns, including, but not limited to, migration, breathing, nursing,
breeding, feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of disruption of behavioral patterns for individual marine mammals
resulting from exposure to the tugs towing and positioning the jack-up
rig. 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 or harassment 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). Accordingly, 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 reasonably estimate the onset of behavioral harassment. NMFS
generally predicts that marine mammals are likely to be behaviorally
affected 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 (rms) for non-explosive impulsive
(e.g., seismic airguns) or intermittent (e.g., scientific sonar)
sources.
Hilcorp's activity includes the use of continuous (tug towing and
positioning the rig) sources, and therefore the RMS SPL 120 dB re 1
[mu]Pa is applicable.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
[[Page 62382]]
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). Hilcorp's activity includes the use of
non-impulsive (tugs towing rig) sources.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS 2018 Technical Guidance, which may be accessed at
<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>.
Table 6--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 [mu]Pa, and cumulative sound exposure level (LE) has
a reference value of 1[mu]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 will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
As described above in the Detailed Description of Specific
Activity, based on in situ measurements of Hilcorp's tug and a review
of the available literature of tugs under load, a source level of 185
dB re 1 [mu]Pa was used for Hilcorp's three tug configuration for
towing the jack-up-rig. Hilcorp contracted SLR Consulting to model the
extent of the Level B harassment isopleth as well as the extent of the
PTS isopleth for their activity.
Rather than applying practical spreading loss, SLR created a more
detailed propagation loss model in an effort to improve the accuracy of
the results by considering the influence of environmental variables
(e.g. bathymetry) at the specific well sites, as Hilcorp's operational
locations are known in advance. Modeling was conducted using dBSea
software. The fluid parabolic equation modeling algorithm was used with
5 Pad[eacute] terms (see pg. 57 in Hilcorp's application for more
detail) to calculate the transmission loss between the source and the
receiver at low frequencies (\1/3\-octave bands, 31.5 Hz up to 1 kHz).
For higher frequencies (1 kHz up to 8 kHz) the ray tracing model was
used with 1,000 reflections for each ray. Sound sources were assumed to
be omnidirectional and modeled as points. The received sound levels for
the project were calculated as follows: (1) One-third octave source
spectral levels were obtained via reference spectral curves with
subsequent corrections based on their corresponding overall source
levels; (2) Transmission loss was modeled at one-third octave band
central frequencies along 100 radial paths at regular increments around
each source location, out to the maximum range of the bathymetry data
set or until constrained by land; (3) The bathymetry variation of the
vertical plane along each modeling path was obtained via interpolation
of the bathymetry dataset which has 83 m grid resolution; (4) The one-
third octave source levels and transmission loss were combined to
obtain the received levels as a function of range, depth, and
frequency; and (5) The overall received levels were calculated at a 1-m
depth resolution along each propagation path by summing all frequency
band spectral levels.
Model Inputs--Bathymetry data used in the model was collected from
the NOAA National Centers for Environmental Information (AFSC, 2019).
Using NOAA's temperature and salinity data, sound speed profiles were
computed for depths from 0 to 100 meters for May, July, and October to
capture the range of possible sound speed depending on the time of year
Hilcorp's work could be conducted. These sound speed profiles were
compiled using the Mackenzie Equation (1981) and are presented in Table
8 of Hilcorp's application. Geoacoustic parameters were also
incorporated into the model. The parameters were based on substrate
type and their relation to depth. These parameters are presented in
Table 9 of Hilcorp's application.
Detailed broadband sound transmission loss modeling in dBSea used
the source level of 185 dB re 1 [mu]Pa at 1 m calculated in one-third
octave band levels (31.5 Hz to 64,000 Hz) for frequency dependent
solutions. The frequencies associated with tug sound sources occur
within the hearing range of marine mammals in Cook Inlet. Received
levels for each hearing marine mammal group based on one-third octave
auditory weighting functions were also calculated and integrated into
the modeling scenarios of dBSea. For modeling the distances to relevant
PTS thresholds, a weighting factor adjustment was not used; instead,
the data on the spectrum associated with their source was used and
incorporated the full auditory weighting function for each marine
mammal hearing group.
Because Hilcorp plans to use the tugs towing the jack-up-rig for
essentially two functions (positioning and towing), the activity was
divided into two parts (stationary and mobile) and two approaches were
taken for modeling the relevant isopleths.
[[Page 62383]]
Stationary--For stationary activity, two locations representative
of where tugs will be stationary positioning the jack-up rig were
selected for the model. These locations are in middle Cook Inlet near
the Tyonek platform, and in lower Trading Bay where the production
platforms are located, with water depths of 40 m and 20 m respectively.
The modeling at these locations assumed a stationary 5-hour exposure to
a broadband spectrum of 185 dB as described above. A 5-hour exposure
duration was chosen to account for the up to 5-hour positioning
attempts on individual days as well as events where the tugs need to
hold the jack-up rig while waiting for a following tide. Stationary
model results are presented in Table 7.
Mobile--For the mobile portion of the activity, a representative
route was used from the Rig Tender's dock in Nikiski to the Tyonek
platform, the northernmost platform in Cook Inlet (representing Middle
Cook Inlet), as well as from the Tyonek Platform to the Dolly Varden
platform in lower Trading Bay and then from the Dolly Varden platform
back to the Rig Tender's Dock in Nikiski. This route is representative
of a typical route the tugs may take; the specific route is not yet
known because the order in which platforms will be drilled with the
jack-up rig is not yet known. The lowest threshold for the onset of PTS
is for high frequency cetaceans at 173 dB. Based on a source level of
185 dB, and assuming practical spreading, the high frequency cetacean
PTS threshold of 173 dB would be reached at 6.3 meters away from the
source. The mobile source modeling assumed a transit speed of 2.06 m/s
for the tug configuration. With an assumed vessel speed of 2.06 m/s, it
would take the vessel 6.11 seconds to traverse a distance of two times
the radius, with two times the radius used because the source is
omnidirectional and the ship is moving in a straight line. Although a
source level of 185 dB incorporates the use of three tugs
simultaneously, because the three tugs will likely not be perfectly
aligned in space (e.g., one could lag slightly behind the forward two),
three separate six second exposures were summed (one for each tug
passing in space) to arrive at a total duration of exposure of 18
seconds. While it is possible the duration of exposure could be as
short as six seconds if all tugs were perfectly aligned, separate
exposures for each tug were considered as the exact formation of the
tugging vessels at any given time is unknown. Mobile source model
results are presented in Table 8.
Because there is no temporal component associated with NMFS'
current Level B threshold, making it a potentially conservative
assumption given the transitory nature of the rig towing activity, the
results of the modeled distance to the 120 dB threshold for both
stationary and mobile tug use are presented in Table 9 below. The
average of these distances was used for calculation of estimated
exposure to Level B harassment (3,850 m).
The locations used in the stationary and mobile source models are
depicted in Figure 2 below.
BILLING CODE 3510-22-P
[[Page 62384]]
[GRAPHIC] [TIFF OMITTED] TN14OC22.070
BILLING CODE 3510-22-C
The outputs of the mobile and stationary models as distances to the
relevant threshold (in meters) are presented below in Tables 7-9.
[[Page 62385]]
Table 7--Average Distances to PTS Thresholds for Stationary Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average distances (m) to PTS threshold by functional hearing group
Location Season -------------------------------------------------------------------------------
LF MF HF PW OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Trading Bay............................... May......................... 100 72 716 59 ..............
Trading Bay............................... July........................ 122 73 697 63 ..............
Trading Bay............................... October..................... 98 72 694 59 ..............
Middle Cook Inlet......................... May......................... 83 83 643 77 ..............
Middle Cook Inlet......................... July........................ 89 85 664 78 ..............
Middle Cook Inlet......................... October..................... 80 84 661 78 ..............
-------------------------------------------------------------------------------
Average............................... ............................ 95 78 679 69 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 8--Average Distances to PTS Thresholds for Mobile Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average distances (m) to PTS threshold by functional hearing group
Location Season -------------------------------------------------------------------------------
LF MF HF PW OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
M2........................................ May......................... .............. .............. 10 .............. ..............
M2........................................ July........................ .............. .............. 5 .............. ..............
M2........................................ October..................... .............. .............. 10 .............. ..............
M11....................................... May......................... .............. .............. 10 .............. ..............
M11....................................... July........................ .............. .............. 5 .............. ..............
M11....................................... October..................... .............. .............. 10 .............. ..............
M22....................................... May......................... .............. .............. 10 .............. ..............
M22....................................... July........................ .............. .............. 5 .............. ..............
M22....................................... October..................... .............. .............. 10 .............. ..............
-------------------------------------------------------------------------------
Average............................... ............................ 0 0 8 0 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 9--Average Distances to Level B Threshold
[stationary and mobile]
[120 dB]
----------------------------------------------------------------------------------------------------------------
Average distance to 120 dB threshold (m) Season average
Waypoint ------------------------------------------------ distance to
May July October threshold (m)
----------------------------------------------------------------------------------------------------------------
M1.............................................. 4,215 3,911 4,352 4,159
M2.............................................. 3,946 3,841 4,350 4,046
M3.............................................. 4,156 3,971 4,458 4,195
M4.............................................. 4,040 3,844 4,364 4,083
M5.............................................. 4,053 3,676 4,304 4,011
M6.............................................. 3,716 3,445 3,554 3,572
M7.............................................. 2,947 2,753 2,898 2,866
M8.............................................. 3,270 3,008 3,247 3,175
M9.............................................. 3,567 3,359 3,727 3,551
M10............................................. 3,600 3,487 3,691 3,593
M11............................................. 3,746 3,579 4,214 3,846
M12............................................. 3,815 3,600 3,995 3,803
M13............................................. 4,010 3,831 4,338 4,060
M14............................................. 3,837 3,647 4,217 3,900
M15............................................. 3,966 3,798 4,455 4,073
M16............................................. 3,873 3,676 4,504 4,018
M18............................................. 5,562 3,893 4,626 4,694
M20............................................. 5,044 3,692 4,320 4,352
M22............................................. 4,717 3,553 4,067 4,112
M24............................................. 4,456 3,384 4,182 4,007
M25............................................. 3,842 3,686 4,218 3,915
M26............................................. 3,690 3,400 3,801 3,630
M27............................................. 3,707 3,497 3,711 3,638
M28............................................. 3,546 3,271 3,480 3,432
M29............................................. 3,618 3,279 3,646 3,514
Average..................................... 3,958 3,563 4,029 3,850
----------------------------------------------------------------------------------------------------------------
[[Page 62386]]
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
Densities for marine mammals in Cook Inlet were derived from NMFS'
Marine Mammal Laboratory (MML) aerial surveys, typically flown in June,
from 2000 to 2018 (Rugh et al., 2005; Shelden et al., 2013, 2015, 2017,
2019). A survey was also conducted in 2021 but density information is
not yet available. While the surveys are concentrated for a few days in
June annually, which may skew densities for seasonally present species,
they are still the best available long-term dataset of marine mammal
sightings available in Cook Inlet. Density was calculated by summing
the total number of animals observed and dividing the number sighted by
the area surveyed. The total number of animals observed accounts for
both lower and upper Cook Inlet. There are no density estimates
available for California sea lions and Pacific white-sided dolphins in
Cook Inlet, as they are so infrequently sighted. Densities are
presented in Table 10 below.
Table 10--Densities of Marine Mammals in Cook Inlet
------------------------------------------------------------------------
Density (indiv/
Species km\2\)
------------------------------------------------------------------------
Humpback whale.......................................... 0.001770
Minke whale............................................. 0.000009
Gray whale.............................................. 0.000075
Fin whale............................................... 0.000311
Killer whale............................................ 0.000601
Beluga whale (MML lower CI)............................. 0.000023
Beluga whale (MML middle CI)............................ 0.001110
Goetz beluga--LCI....................................... 0.011106
Goetz beluga--NCI....................................... 0.001664
Goetz beluga--TB........................................ 0.015053
Dall's porpoise......................................... 0.000154
Harbor porpoise......................................... 0.004386
Pacific white-sided dolphin............................. 0.000000
Harbor seal............................................. 0.241401
Steller sea lion........................................ 0.007609
California sea lion..................................... 0.000000
------------------------------------------------------------------------
For beluga whales, two densities were considered as a comparison of
available data. The first source considered was directly from the MML
aerial surveys, as described above. Sighting data collected during
aerial surveys is collected and then several correction factors are
applied to address perception, availability, and proximity bias. These
corrected sightings totals are then divided by the total area covered
during the survey to arrive at a density value. Densities were derived
for the entirety of Cook Inlet as well as for middle and lower Cook
Inlet. Densities across all three regions are low and there is a known
effect of seasonality on the distribution of the whales. Thus,
densities derived directly from surveys flown in June might
underestimate the density of beluga whales in lower Cook Inlet at other
ice-free times of the year.
The other mechanism for arriving at beluga whale density considered
here is the Goetz et al. (2012) habitat-based model. This model is
derived from sightings and incorporates depth soundings, coastal
substrate type, environmental sensitivity index, anthropogenic
disturbance, and anadromous fish streams to predict densities
throughout Cook Inlet. The output of this model is a beluga density map
of Cook Inlet, which predicts spatially explicit density estimates for
Cook Inlet belugas. Using the resulting grid densities, average
densities were calculated for two regions applicable to Hilcorp's
operations. The densities applicable to the area of activity (i.e., the
North Cook Inlet Unit density for middle Cook Inlet activities and the
Trading Bay density for activities in Trading Bay) are provided in
Table 11 below and were carried forward to the exposure estimates.
Likewise, when a range is given, the higher end of the range was used
out of caution to calculate exposure estimates (i.e., Trading Bay in
the Goetz model has a range of 0.004453 to 0.015053; 0.015053 was used
for the exposure estimates).
Table 11--Cook Inlet Beluga Whale Densities Based on Goetz et al. (2012)
Habitat Model
------------------------------------------------------------------------
Beluga whale density
Project Location (ind/km\2\)
------------------------------------------------------------------------
North Cook Inlet Unit (middle Cook Inlet)...... 0.001664
Trading Bay Area............................... 0.004453-0.015053
------------------------------------------------------------------------
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate for each of the two
IHAs.
Year 1 IHA--As described above, Hilcorp's tug towing rig activity
was divided into two portions for the purpose of take estimation:
stationary and mobile activity. For stationary activity, 5 hours of
sound production per day was assumed for up to 14 days (seven moves or
segments consisting of 2 days each). For the mobile portion of the
activity, 1 day of 9 hours of mobile activity (assuming a source
velocity of 2.06 m/s) and 6 days of 6 hours of mobile activity were
assumed, for a total of 7 rig moves. The first 5 stationary hours are
assumed to occur on the same day as the mobile hours, the second 5
stationary hours will occur the following day. The first 5 stationary
[[Page 62387]]
hours are assumed to occur on the same day as the mobile hours, the
second 5 stationary hours will occur the following day.
Year 2 IHA--For stationary activity, 5 hours of sound production
per day was assumed for up to 16 days. For mobile activity, 9 hours of
sound production was assumed for 2 days, as well as 6 hours of sound
production for 6 days, for a total of eight rig moves.
The ensonified areas calculated per activity type (stationary and
mobile) for a single day were multiplied by marine mammal densities to
get an estimate of exposures per day. This was then multiplied by the
number of days of that type of activity (stationary or mobile) to
arrive at the number of estimated exposures per year per activity type.
These exposures by activity type were then summed to result in a number
of exposures per year for all tug towing rig activity. The estimated
exposures are provided below in Tables 12 and 13 for Year 1 and Year 2
of activity, respectively. As we are now considering one less rig
mobilization in Year 1 than was considered in the notice of proposed
IHAs, the calculated exposures for Year 1 are slightly lower than those
of Year 2. There are two estimates for beluga whales provided in the
tables below to demonstrate the difference in the calculations based on
the chosen density value. As exposure estimates were calculated based
on specific potential rig moves or well locations, the density value
for beluga whales that was carried through the estimate was the higher
density value for that particular location. There are no estimated
exposures based on this method of calculation for Pacific white-sided
dolphins and California sea lions because the assumed density is 0
animals/km\2\.
Table 12--Total Calculated Exposures for Year 1
----------------------------------------------------------------------------------------------------------------
Group Species Level A Level B
----------------------------------------------------------------------------------------------------------------
LF Cetaceans.................................. Humpback whale.................. 0.000 3.065
Minke whale..................... 0.000 0.016
Gray whale...................... 0.000 0.129
Fin whale....................... 0.000 0.538
MF Cetaceans.................................. Killer whale.................... 0.000 1.041
Beluga whale NMFS............... 0.000 1.922
Beluga whale Goetz.............. 0.000 9.411
Pacific white-sided dolphin..... 0.000 0.000
HF Cetaceans.................................. Dall's porpoise................. 0.001 0.266
Harbor porpoise................. 0.031 7.595
Phocids....................................... Harbor seal..................... 0.011 418.051
Otariids...................................... Steller sea lion................ 0.000 13.176
California sea lion............. 0.000 0.000
----------------------------------------------------------------------------------------------------------------
Table 13--Total Calculated Exposures for Year 2
----------------------------------------------------------------------------------------------------------------
Group Species Level A Level B
----------------------------------------------------------------------------------------------------------------
LF Cetaceans.................................. Humpback whale.................. 0.000 4.058
Minke whale..................... 0.000 0.021
Gray whale...................... 0.000 0.171
Fin whale....................... 0.000 0.712
MF Cetaceans.................................. Killer whale.................... 0.000 1.379
Beluga whale NMFS............... 0.000 2.545
Beluga whale Goetz.............. 0.000 11.651
Pacific white-sided dolphin..... 0.000 0.000
HF Cetaceans.................................. Dall's porpoise................. 0.001 0.353
Harbor porpoise................. 0.038 10.057
Phocids....................................... Harbor seal..................... 0.012 553.565
Otariids...................................... Steller sea lion................ 0.000 17.448
California sea lion............. 0.000 0.000
----------------------------------------------------------------------------------------------------------------
Based on the analysis described above, NMFS has not authorized take
via Level A harassment related to Hilcorp's tug towing drill rig
activity. For mobile tugging, the distances to the PTS thresholds for
high frequency cetaceans (the only functional hearing group of concern
based on the model results) are smaller than the overall size of the
tug and rig configuration, making it unlikely a cetacean would remain
close enough to the tug engines to incur PTS. For stationary
positioning of the jack up rig, the PTS isopleths are up to 679 m for
high frequency cetaceans, but calculated on the assumption that an
animal would remain within several hundred meters of the jack-up rig
for the full 5 hours of noise-producing activity. Given the location of
the activity is not in an area known to be essential habitat for any
marine mammal species with extreme site fidelity over the course of 2
days, the occurrence of PTS is unlikely. A table indicating the number
of takes, by Level B harassment, authorized is provided below.
Table 14--Takes (by Level B Harassment) Calculated and Authorized for Year 1 IHA and Year 2 IHA
----------------------------------------------------------------------------------------------------------------
Year 1 calculated Year 1 authorized Year 2 calculated Year 2 authorized
----------------------------------------------------------------------------------------------------------------
Humpback whale............... 3.065................ 5 4.058............... 6
Minke whale.................. 0.016................ 6 0.021............... 6
[[Page 62388]]
Gray whale................... 0.129................ 2 0.171............... 2
Fin whale.................... 0.538................ 4 0.712............... 4
Killer whale................. 1.041................ 10 1.379............... 10
Beluga whale................. 1.922 (MML), 9.411 11 2.545 (MML), 11.651 22
(Goetz). (Goetz).
Pacific white-sided dolphin.. 0.................... 3 0................... 3
Dall's porpoise.............. 0.266................ 6 0.353............... 6
Harbor porpoise.............. 7.595................ 44 10.057.............. 44
Harbor seal.................. 418.051.............. 418 553.565............. 554
Steller sea lion............. 13.176............... 13 17.448.............. 17
California sea lion.......... 0.................... 2 0................... 2
----------------------------------------------------------------------------------------------------------------
As illustrated by the table above, the estimated exposures for
several species are less than one. While uncommon, these species have
been previously sighted in Cook Inlet and some are unlikely to appear
as solitary individuals when sighted.
For humpback whales, the number of takes authorized is increased
from the calculated estimate of four to six individuals. There were two
sightings of three humpback whales observed near Ladd Landing north of
the Forelands during the Harvest Alaska CIPL project (Sitkiewicz et
al., 2018). Based on documented observations during the CIPL survey
(the survey nearest the Action Area), Hilcorp requested six takes of
humpback whales to allow for up to two sightings of three individuals,
consistent with what was observed during the CIPL project. We expect a
small number of humpback whale groups will be exposed, with most of
these groups consisting of one or two animals. There is a small
probability more humpbacks are exposed than the calculated, three
humpbacks in Year 1 and four in Year 2, therefore, we added an
additional median group size of two humpback whales to each year
resulting in an exposure estimate of five humpbacks in Year 1 and six
in Year 2.
Minke whale takes authorized are increased from the calculated less
than one individual to five. Minke whales are commonly sighted in
groups of two or three, as well as sightings of individuals. There were
eight sightings of eight minke whales observed during the 2019 Hilcorp
lower Cook Inlet seismic survey (Fairweather Science, 2020). As the
occurrence of minke whales is expected to be less in middle Cook Inlet
than lower Cook Inlet and considering the observed group sizes, Hilcorp
is requesting six takes of minke whale to allow for the possibility of
two sightings of a group of three individuals, both in Year 1 and again
in Year 2.
During Apache's 2012 seismic program, nine gray whales were
observed in June and July (Lomac-MacNair et al., 2013). During Apache's
seismic program in 2014, one gray whale was observed (Lomac-MacNair et
al., 2014). During SAExploration's seismic survey in 2015, the 2018
CIPL project, and Hilcorp's 2019 seismic survey, no gray whales were
observed (Kendall et al., 2015; Sitkiewicz et al., 2018; Fairweather
Science, 2020). Considering the Action Area is in middle Cook Inlet
where sightings of gray whales are less common, Hilcorp is requesting
two takes of gray whales to allow for the potential occurrence of two
individual gray whales both in Year 1 and again in Year 2.
The number of fin whale takes authorized is increased from one to
four individuals, as they may be seen in groups of two to seven
individuals. During seismic surveys conducted in 2019 by Hilcorp in the
lower Cook Inlet, fin whales were recorded in groups ranging in size
from one to 15 individuals (Fairweather, 2020). During the NMFS aerial
surveys in Cook Inlet from 2000 to 2018, 10 sightings of 26 estimated
individual fin whales in lower Cook Inlet were observed (Shelden et
al., 2013, 2015, 2016, 2019). A total authorized take of four fin
whales would account for two sightings of two animals, which is the
lower end of the range of common group size. Exposure of up to four fin
whales could occur in Year 1 and again in Year 2.
The number of authorized killer whale takes is increased to 10 from
the calculated exposure of one. Killer whales are typically sighted in
pods of a few animals to 20 or more (NOAA, 2022b). During seismic
surveys conducted in 2019 by Hilcorp in the lower Cook Inlet, 21 killer
whales were observed, either as single individuals or in groups ranging
in size from 2 to 5 individuals (Fairweather, 2020). Based on
documented sightings, Hilcorp requested 10 takes of killer whales to
allow for 2 sightings with a group size of 5 individuals in Year 1 and
again in Year 2.
Depending on the density data used for each activity, the estimated
annual exposures for beluga whales is 3 to 10 animals. The number of
takes authorized for beluga whales is 11 animals for Year 1 and 22
animals in Year 2 to allow for the possibility that more than one
observation of typical Cook Inlet beluga groups occurs. The 2018 MML
aerial survey (Shelden and Wade, 2019) estimated a median group size of
approximately 11 beluga whales, although group sizes were highly
variable (2 to 147 whales) as was the case in previous survey years
(Boyd et al., 2019). We are not accounting for multiple groups of 11
belugas for Year 1 given that a large portion of the total mobilization
distance has already been traveled, making an encounter with multiple
beluga groups less likely. Additionally, vessel-based surveys in 2019
observed beluga whale groups in the Susitna River Delta (roughly 24 km
[15 miles] north of the Tyonek Platform) that ranged from 5 to 200
animals (McGuire et al., 2021). The very large groups seen in the
Susitna River Delta are not expected near Hilcorp's platforms, however,
smaller groups (i.e., around the median group size) could be traveling
through to access the Susitna River Delta and other nearby coastal
locations, particularly in the shoulder seasons when belugas are more
likely to occur in middle Cook Inlet.
The number of Dall's porpoise takes authorized is increased from
less than one estimated individual to six. Dall's porpoises are usually
found in groups averaging between two and 12 individuals (NOAA, 2022c).
During seismic surveys conducted in 2019 by Hilcorp in the lower Cook
Inlet, Dall's porpoises were recorded in groups
[[Page 62389]]
ranging in size from two to seven individuals (Fairweather, 2020). The
2012 Apache survey recorded two groups of three individual Dall's
porpoises (Lomac-MacNair, 2014). Because occurrence of Dall's porpoise
is anticipated to be less in middle Cook Inlet than lower Cook Inlet,
the smaller end of documented group sizes (three individuals) is used,
and Hilcorp requests six takes of Dall's porpoise to allow for two
sightings of three individuals similar to the numbers observed during
the 2012 Apache survey. The same number of takes are authorized in Year
1 and Year 2 because the calculated exposure for each year is less than
one, making the group size methodology equally applicable to Year 1 and
Year 2.
Harbor porpoise takes are increased from an estimated 10 takes to
44 takes. Shelden et al. (2014) compiled historical sightings of harbor
porpoises from lower to upper Cook Inlet that spanned from a few
animals to 92 individuals. The 2018 CIPL project that occurred just
north of the Action Area in Cook Inlet reported 29 sightings of 44
individuals (Sitkiewicz et al., 2018). While the duration of days that
the tugs are towing a jack-up rig will be less than the CIPL project,
given the increase in sightings of harbor porpoise in recent years, the
sighting of harbor porpoise during Hilcorp's rig move in June 2022, and
the inability to shut down the tugs, Hilcorp requests 44 takes of
harbor porpoise, commensurate with the number observed in the nearby
CIPL project. Once the rig move to Tyonek is removed from the
calculation, as Hilcorp completed that work before issuance of these
IHAs, calculated exposure of harbor porpoise is less in Year 1 than in
Year 2. However, based on Hilcorp's monitoring report during their
initial rig move, more harbor porpoises were seen than expected, so
NMFS did not reduce the authorized take for Year 1 from what was
originally requested (which included the Tyonek rig move in the
calculation). As a result, 44 takes of harbor porpoise are authorized
for both Year 1 and Year 2.
Take of harbor seal and Steller sea lion authorized for Year 1 and
Year 2 is based on the calculated exposure. Because Hilcorp already
completed a rig move to Tyonek and that effort has been removed from
the calculation, take for both species in Year 1 is less than in Year
2.
Calculated take of Pacific white-sided dolphins and California sea
lions was zero because the assumed density in Cook Inlet is zero. For
California sea lions, any potential sightings would likely be lone out
of habitat individuals. Two solitary individuals were seen during the
2012 Apache seismic survey in Cook Inlet (Lomac-MacNair et al., 2013).
Two takes are authorized based on the potential that two lone animals
could be sighted over a year of work, as was seen during Apache's year
of work. For Pacific white-sided dolphins, the only reported visual
sightings that NMFS is aware of was three dolphins from Apache's
monitoring efforts in 2014 in Kenai, which is in the general vicinity
of Hilcorp's planned activities. Therefore, NMFS authorized three takes
of Pacific white-sided dolphins annually in case a repeated group of
similar size is encountered. For both species, the same number of takes
are authorized for Year 1 and Year 2 because the calculated exposure
for each year would be zero given the lack of density data, making the
group size methodology equally applicable to Year 1 and Year 2.
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. 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, we
carefully consider 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, as
well as subsistence uses. 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, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
Mitigation for Marine Mammals and Their Habitat
NMFS anticipates the project, in both of the two IHAs, will create
an acoustic footprint above ambient sound levels of approximately 45
km\2\ around the tugs positioning the jack-up rig or for approximately
3.8 km in all directions along a towing trajectory of approximately 64
km (40 mi). There is a discountable potential for marine mammals to
incur PTS from the project, as source levels are relatively low, non-
impulsive, and animals would have to remain at very close distances for
multiple hours to accumulate acoustic energy at levels that could
damage hearing. Therefore, we do not believe there is potential for
Level A harassment. However, Hilcorp will implement a number of
mitigation measures designed to reduce the potential for and severity
of Level B harassment, protect belugas in important beluga whale
habitat, and minimize the acoustic footprint of the project.
The tugs towing a jack-up rig are not able to shut down while
transiting or positioning the rig. Hilcorp will maneuver the tugs
towing the jack-up rig such that they maintain a consistent speed
(approximately 4 knots) and avoid multiple changes of speed and
direction to make the course of the vessels as predictable as possible
to marine mammals in the surrounding environment, characteristics that
are expected to be associated with a lower likelihood of disturbance.
Hilcorp will implement a clearance zone of 1,500 meters around the
centerpoint of the three tug configuration and will employ two NMFS-
approved protected species observers (PSOs) to conduct marine mammal
monitoring for all mobile and stationary activity involving tugs towing
attached to the jack-up rig. Prior to commencing activities during
daylight hours or if there is a 30-minute lapse in operational
activities, the PSOs will monitor the clearance zone for marine mammals
for 30 minutes. If no marine mammals are observed, operations may
commence. If a marine mammal(s) is observed within the clearance zone
during the clearing, the PSOs will
[[Page 62390]]
continue to watch until either: (1) the animal(s) is outside of and on
a path away from the clearance zone; or (2) 15 minutes have elapsed if
the species was a pinniped or small cetacean, or 30 minutes for large
cetaceans whales. Once the PSOs have determined one of those conditions
are met, operations may commence.
Should a marine mammal be observed during towing or positioning,
the PSOs will monitor and carefully record any reactions observed until
the jack-up rig has reached its intended position. No new operational
activities would be started until the animal leaves the area;
transitioning from tugging to positioning without shutting down is not
considered a new operational activity. PSOs will also collect
behavioral information on marine mammals sighted during monitoring
efforts.
Hilcorp will make every effort to operate with the tide, resulting
in a low power output from the tugs towing the jack-up rig. If human
safety or equipment integrity is at risk, Hilcorp may necessarily
operate in an unfavorable tidal state. Due to the nature of tidal
cycles in Cook Inlet, it is possible the most favorable tide for the
towing operation will occur during nighttime hours. Hilcorp will
operate the tugs towing the jack-up rigs at night if the nighttime
operations result in a lower power output from the tugs by operating
with a favorable tide.
In low-light conditions, night-vision devices shown to be effective
at detecting marine mammals in low-light conditions (e.g., PVS-7 night-
vision devices or similar) will be provided to PSOs to aid in low-light
visibility. Every effort will be made to observe that the clearance
zone is free of marine mammals by using night-vision devices, however
it may not always be possible to see and clear the entire clearance
zone prior to nighttime transport. PSOs will monitor the greatest
extent feasible for 30 minutes immediately prior to the start of load
bearing activities. If no marine mammals are observed, operations may
commence. If a marine mammal is observed within the during the
clearing, the PSOs will continue to watch until either: (1) the
animal(s) is outside of and on a path away from the clearance zone; or
(2) 15 minutes have elapsed if the species was a pinniped or small
cetacean, or 30 minutes for large cetaceans whales. Once the PSOs have
determined one of those conditions are met, operations may commence.
Out of concern for potential disturbance to Cook Inlet beluga
whales in sensitive and essential habitat, Hilcorp will not conduct
noise-producing activity within 16 km (10 miles) of the mean lower-low
water (MLLW) line of the Susitna River Delta (Beluga River to the
Little Susitna River) between April 15 and November 15 with the
exception of work conducted at the Tyonek platform. The dates of
applicability of this exclusion zone have been expanded based on new
available science, including visual surveys and acoustic studies, which
indicate that substantial numbers of Cook Inlet beluga whales continue
to occur in the Susitna Delta area through at least mid-November (M.
Castellote, pers. comm., T. McGuire, pers. comm.). As the MLLW is not a
straight line but rather a jagged contour following the coastline, it
is difficult to determine the southernmost extent of the zone during
operations. For ease of implementation, the southernmost extent of the
Susitna Delta exclusion zone will be considered a straight line from
Tyonek at the west to Point Possession at the east (see Figure 3
below).
BILLING CODE 3510-22-P
[[Page 62391]]
[GRAPHIC] [TIFF OMITTED] TN14OC22.071
BILLING CODE 3510-22-C
During the course of consultation under section 7 of the ESA,
Hilcorp notified NMFS that adhering to the exclusion zone for the
Tyonek platform would not be practicable given the operational and
human safety concerns of accessing the platform outside of the open
water season. Prior to tugging the jack-up rig to and from the Tyonek
platform, Hilcorp will conduct a systematic aerial survey of all marine
waters within a 10 mile radius of the Tyonek platform that intersects
with the Susitna Delta exclusion zone, termed the aerial survey area
(see Figure 3) to ensure the area is clear of beluga whales. Aerial
surveys will be flown with a PSO observing for beluga whales at an
altitude of approximately 1,000 ft (305 m). This survey will be
conducted no more than 12 hours (one half of one tide cycle) prior to
the proposed departure of the rig from its moored or anchored location.
If beluga whales are observed during the aerial survey prior to
mobilizing the jack-up rig to or from the Tyonek platform, Hilcorp will
not begin mobilization of the rig until a subsequent aerial survey
indicates the aerial survey area contains no beluga whales. Starting
from the proposed departure date, Hilcorp will conduct aerial surveys
as described above and if belugas are seen in the aerial survey area
will defer moving the jack-up rig if there is another departure date
that fits the tide/tug criteria for moving onto and off of the dock
within 8 days. If the rig move is deferred until the next departure
window occurring within 8 days of the first proposed departure date,
Hilcorp will again conduct aerial surveys and will defer moving the rig
until the last available tide for departure that allows the tugs to
complete the transport in that second departure time frame. If beluga
whales are observed in the aerial survey area prior to the last
available tide in the already deferred second departure time-frame,
Hilcorp will move the jack-up rig to its next location. If there is not
another departure date within 8 days of the first proposed departure
date, Hilcorp will conduct multiple aerial surveys (weather permitting)
as described above and if belugas are seen in the aerial survey area
will defer moving the rig until the last available tide in that initial
departure window that fits with the tugs availability to complete the
rig transport. If ice or other safety conditions exist that require the
tugs to move the jack-up rig to preserve human safety, Hilcorp will
move the jack-up rig to its next location even if belugas are observed
in the aerial survey area.
Based on our evaluation of these measures, for both IHAs, 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 and on the availability of
such species or stock for subsistence uses.
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
[[Page 62392]]
present in the action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density).
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; 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).
<bullet> Mitigation and monitoring effectiveness.
Hilcorp will abide by all monitoring and reporting measures
contained within their Marine Mammal Monitoring and Mitigation Plan,
dated March 7, 2022. A summary of those measures and additional
requirements required by NMFS is provided below.
A minimum of two NMFS-approved PSOs will be on-watch during all
activities wherein the jack-up rig is attached to the tugs for the
duration of the project. Minimum requirements for a PSO include:
(a) Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
(b) Advanced education in biological science or related field
(undergraduate degree or higher required)--PSOs may also substitute
Alaska native traditional knowledge for experience;
(c) Experience and ability to conduct field observations and
collect data according to assigned protocols (this may include academic
experience);
(d) Experience or training in the field identification of marine
mammals, including the identification of behaviors;
(e) Sufficient training, orientation, or experience with the
activity to provide for personal safety during observations;
(f) Writing skills sufficient to prepare a report of observations
including but not limited to the number and species of marine mammals
observed; dates and times when tugging activities were conducted; dates
and times when tugging activities were suspended; and marine mammal
behavior; and
(g) Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
PSOs will be stationed aboard a tug or the jack-up rig, work in
shifts lasting no more than 4 hours without a minimum of a 1 hour
break, and will not be on-watch for more than 12 hours within a 24-hour
period.
Hilcorp will submit monthly reports for all months in which tugs
towing or positioning the jack-up rig occurs. A draft marine mammal
monitoring report would be submitted to NMFS within 90 days after the
completion of the tug towing jack-up rig activities for the year. It
will include an overall description of work completed, a narrative
regarding marine mammal sightings, and associated marine mammal
observation data sheets. Specifically, the report must include:
<bullet> Date and time that monitored activity begins or ends;
<bullet> Construction activities occurring during each observation
period;
<bullet> Weather parameters (e.g., percent cover, visibility);
<bullet> Water conditions (e.g., sea state, tide state);
<bullet> Species, numbers, and, if possible, sex and age class of
marine mammals;
<bullet> Description of any observable marine mammal behavior
patterns, including bearing and direction of travel and distance from
tugging activity;
<bullet> Distance from tugging activities to marine mammals and
distance from the marine mammals to the observation point;
<bullet> Locations of all marine mammal observations; and
<bullet> Other human activity in the area.
If no comments are received from NMFS within 30 days, the draft
final report will constitute the final report. If NMFS submits
comments, Hilcorp will submit a final report addressing NMFS comments
within 30 days after receipt of comments.
In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by the IHAs
(if issued), such as an injury, serious injury or mortality, Hilcorp
would immediately cease the specified activities and report the
incident to the Chief of the Permits and Conservation Division, Office
of Protected Resources, NMFS, and the Alaska Regional Stranding
Coordinator. The report would include the following information:
<bullet> Description of the incident;
<bullet> Environmental conditions (e.g., Beaufort sea state,
visibility);
<bullet> Description of all marine mammal observations in the 24
hours preceding the incident;
<bullet> Species identification or description of the animal(s)
involved;
<bullet> Fate of the animal(s); and
<bullet> Photographs or video footage of the animal(s) (if
equipment is available).
Activities would not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS would work with Hilcorp to
determine what is necessary to minimize the likelihood of further
prohibited take and ensure MMPA compliance. Hilcorp would not be able
to resume their activities until notified by NMFS via letter, email, or
telephone.
In the event that Hilcorp discovers an injured or dead marine
mammal, and the lead PSO determines that the cause of the injury or
death is unknown and the death is relatively recent (e.g., in less than
a moderate state of decomposition as described in the next paragraph),
Hiclrop would immediately report the incident to the Chief of the
Permits and Conservation Division, Office of Protected Resources, NMFS,
and the NMFS Alaska Stranding Hotline and/or by email to the Alaska
Regional Stranding Coordinator. The report would include the same
information identified in the paragraph above. Activities would be able
to continue while NMFS reviews the circumstances of the incident. NMFS
would work with Hilcorp to determine whether modifications in the
activities are appropriate.
In the event that Hilcorp discovers an injured or dead marine
mammal and the lead PSO determines that the injury or death is not
associated with or related to the activities authorized in the IHAs
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), Hilcorp would report the incident
to the
[[Page 62393]]
Chief of the Permits and Conservation Division, Office of Protected
Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or by email
to the Alaska Regional Stranding Coordinator, within 24 hours of the
discovery. Hilcorp would provide photographs or video footage (if
available) or other documentation of the stranded animal sighting to
NMFS and the Marine Mammal Stranding Network.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
the species listed in Table 15, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar in nature. 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. Where there are meaningful differences between species
or stocks, or groups of species, in anticipated individual responses to
activities, impact of expected take on the population due to
differences in population status, or impacts on habitat, they are
described independently in the analysis below.
The project would create an acoustic footprint around the project
area for a total of 14 to 16 days per year from approximately April
through October, though not necessarily in the same calendar year.
Noise levels within the footprint would reach or exceed 120 dB rms. We
anticipate the 120 dB footprint to be limited to no more than 45 km\2\
around the tugs positioning the jackup rig or approximately 3.8 km in
all directions along a towing trajectory of approximately 64 km. The
habitat within the footprint is not heavily used by marine mammals
during the project time frame (e.g., Cook Inlet beluga whale Critical
Habitat Area 2, within which the activity resulting in the take of
marine mammals is anticipated to potentially occur, is designated for
beluga fall and winter use) and marine mammals are not known to engage
in critical behaviors associated with this portion of Cook Inlet (e.g.,
no known breeding grounds, foraging habitat, etc.). Most animals will
likely be transiting through the area; therefore, exposure would be
brief. The tugs would be moving at a relatively slow speed and in a
predictable manner that is not expected to result in more severe
behavioral responses. Animals may swim around the project area,
avoiding closer approaches to the boats, but we do not expect them to
abandon any intended path.
Feeding behavior is not likely to be significantly impacted, as no
areas of biological significance for marine mammal feeding are known to
exist in the project area and individual marine mammals are not
expected to be exposed to the noise from the activities repeatedly or
in long durations. We also expect the number of animals exposed to be
small relative to population sizes. Finally, Hilcorp will minimize
potential exposure of marine mammals to elevated noise levels by not
commencing tugging activities if marine mammals are observed within the
immediate starting area. Hilcorp is also able to reduce the impact of
their activity by conducting tugging operations with favorable tides
whenever feasible. Given this, any behavioral disturbance is expected
to be comparatively low level and unlikely to affect the reproduction
success or survival of any individuals, much less the population or
stock.
Potential impacts to marine mammal habitat were discussed
previously in this document (see Potential Effects of Specified
Activities on Marine Mammals and their Habitat). Marine mammal habitat
may be impacted by elevated sound levels, but these impacts would be
temporary. In addition to being temporary and short in overall
duration, the acoustic footprint of both years of activity is small
relative to the overall distribution of the animals in the area and
their use of the area.
In summary and as described above, the following factors primarily
support our determinations that the impacts resulting from the
activities described for these two IHAs are not expected to adversely
affect the species or stock through effects on annual rates of
recruitment or survival:
<bullet> No mortality, serious injury, or injury is anticipated or
authorized;
<bullet> The mobile portion of the project does not involve noise
sources capable of inducing PTS in any species other than high
frequency cetaceans, and due to the small size of the PTS isopleth for
high frequency cetaceans (6 meters), it is unlikely to occur;
<bullet> Exposure would likely be brief given transiting behavior
of marine mammals in the action area and the small number of days on
which the activity is occurring;
<bullet> Marine mammal densities are low in the project area;
therefore, there will not be substantial numbers of marine mammals
exposed to the noise from the project compared to the affected
population sizes; and
<bullet> Hilcorp will monitor for marine mammals daily and minimize
exposure to operational activities.
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
activity described in the Year 1 IHA will have a negligible impact on
all affected marine mammal species or stocks. Also, separately, NMFS
finds that the total marine mammal take from the activity described in
the Year 2 IHA will have a negligible impact on all affected marine
mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take 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
[[Page 62394]]
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 (as it is for all stocks in
both the Year 1 and Year 2 IHAs), 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.
Table 15 provides the quantitative analysis informing our small
numbers determinations for the Year 1 and Year 2 IHAs. For most
species, the amount of take authorized represents less than
approximately two percent of the population for each IHA. For beluga
whales, the amount of take authorized represents slightly under 8
percent of the population for each IHA.
Table 15--Percent of Stock Authorized To Be Taken by Level B Harassment Under Each IHA
----------------------------------------------------------------------------------------------------------------
Abundance Authorized Percent of
Species Stock (Nbest) take (Level B) stock
----------------------------------------------------------------------------------------------------------------
Year 1:
Humpback whale.................... Western North Pacific; 1,107; 10,103 5 0.45; 0.05
Central North Pacific.
Minke whale....................... Alaska.................. 1,233 6 0.49
Gray whale........................ Eastern Pacific......... 26,960 2 0.01
Fin whale......................... Northeastern Pacific.... 2,554 4 0.16
Killer whale...................... Alaska Resident, Gulf of 587; 2,347 10 1.7; 0.43
Alaska, Aleutian
Islands, and Bering Sea
Transient.
Beluga whale...................... Cook Inlet.............. 279 11 3.94
Pacific white-sided dolphin....... North Pacific........... 26,880 3 0.01
Dall's porpoise................... Alaska.................. 83,400 6 0.01
Harbor porpoise................... Gulf of Alaska.......... 31,046 44 0.14
Harbor seal.
[…truncated; see source link]Indexed from Federal Register on October 14, 2022.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.