Notice2022-09916
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
May 9, 2022
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from Hilcorp Alaska LLC (Hilcorp) for authorization to take marine mammals incidental to tugboats towing a drill rig in Cook Inlet, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue two successive incidental harassment authorizations (IHAs) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, one-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorizations and agency responses will be summarized in the final notice of our decision.
Full Text
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[Federal Register Volume 87, Number 89 (Monday, May 9, 2022)]
[Notices]
[Pages 27597-27624]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-09916]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XB882]
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; proposed incidental harassment authorizations; request
for comments on proposed authorizations.
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SUMMARY: NMFS has received a request from Hilcorp Alaska LLC (Hilcorp)
for authorization to take marine mammals incidental to tugboats towing
a drill rig in Cook Inlet, Alaska. Pursuant to the Marine Mammal
Protection Act (MMPA), NMFS is requesting comments on its proposal to
issue two successive incidental harassment authorizations (IHAs) to
incidentally take marine mammals during the specified activities. NMFS
is also requesting comments on a possible one-time, one-year renewal
that could be issued under certain circumstances and if all
requirements are met, as described in Request for Public Comments at
the end of this notice. NMFS will consider public comments prior to
making any final decision on the issuance of the requested MMPA
authorizations and agency responses will be summarized in the final
notice of our decision.
DATES: Comments and information must be received no later than June 8,
2022.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
[[Page 27598]]
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Written comments should be submitted
via email to <a href="/cdn-cgi/l/email-protection#4f061b1f6116203a21280f21202e2e61282039"><span class="__cf_email__" data-cfemail="f3baa7a3ddaa9c869d94b39d9c9292dd949c85">[email protected]</span></a>.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at
<a href="http://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: 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.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review its proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
Accordingly, NMFS is preparing an Environmental Assessment (EA) to
consider the environmental impacts associated with the issuance of the
proposed IHAs. NMFS' EA will be made available 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> at the time of publication. We will review
all comments submitted in response to this notice prior to concluding
our NEPA process or making a final decision on the IHA requests.
Summary of Request
On January 13, 2022, NMFS received a request from Hilcorp for two
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 eleven
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, an IHA is appropriate.
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, vibratory sheet pile driving, and drilling of exploratory
wells. 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 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
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 in the
remaining effective period of the ITRs. As a result, the only remaining
activity to be analyzed is the use of tugs towing a jack-up rig. NMFS
proposes to authorize incidental take from the tugs towing a jack-up
rig through two sequential IHAs as the appropriate mechanism, given
that there are no more activities occurring under the ITRs, no serious
injury or mortality is expected, and Hilcorp's timing needs.
Description of Proposed Activity
Overview
Hilcorp Alaska, LLC (Hilcorp) plans to carry out activities that
will occur over two separate one-year periods--from April 1, 2022 to
March 31, 2023 (Year 1) and from April 1, 2023 to March 31, 2024 (Year
2). Hilcorp plans to use three 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 two 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 proposed would occur in between those activities, for
approximately 16 days per year for Year 1 and Year 2.
[[Page 27599]]
Table 1--Dates and Durations of Planned Activities in Cook Inlet
----------------------------------------------------------------------------------------------------------------
Duration of
Project type Cook inlet region Timing activity *
(days)
----------------------------------------------------------------------------------------------------------------
Year 1:
Plug and Abandonment of Well Middle Cook Inlet...... April-November.................. 30
17589.
Production Drilling.............. Middle Cook Inlet April-November.................. 180
Trading Bay.
Year 2:
Production Drilling.............. Middle Cook Inlet April-November.................. 180
Trading Bay.
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* 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 proposed activities would 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 27600]]
[GRAPHIC] [TIFF OMITTED] TN09MY22.030
BILLING CODE 3510-22-C
Detailed Description of Specific Activity
Hilcorp proposes 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 proposes 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 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.
[[Page 27601]]
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 proposes to 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 mobilized and demobilized via towing by
three ocean-going tugs from and to the Rig Tenders Dock in Nikiski,
Alaska. A high slack tide is necessary for the tugs to approach close
enough to shore to attach and mobilize the jack-up rig from the Rig
Tenders Dock. Because Hilcorp's production platforms/well sites are
north of the initial mobilization site, the tugs will begin their
transit from Nikiski against an outgoing tide. To minimize transit time
against the outgoing tide and reduce power output, the tugs will first
tow the jack-up rig to a location near the Offshore Systems Kenai dock
for approximately three hours, which provides protection from the fast
outgoing tidal current. Protection from the outgoing tidal current will
allow the tugs to expend less power holding the jack-up rig in position
than they would if they continued to transit against the tide. The tugs
will begin transiting north again when the tide changes to an incoming
tide, which is about six hours after the high slack tide. Towing the
jack-up rig northward with an incoming 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 enables 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, 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 three 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 the
safety of humans 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 proposes use of
three tugs to pull the jack-up rig for plugging and abandonment (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 multibeam 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 an animal 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
[[Page 27602]]
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 (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). This small radius
would overlap substantially with the physical footprint of the platform
and other equipment, so Hilcorp is not requesting take for this
activity and it is not considered further in our analysis. 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 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).
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.
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
proposed 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 SSC measured tugs pulling the jack-up-rig at various
power outputs. This SSV returned a source level of 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% 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 8,2000 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 but rather
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
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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 180 6,000 Roberts Bank Terminal 2
power. Technical Report 2014.
Seaspan Resolution............... 30 N/A Berthing at full 200 6,000
power.
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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.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species.
Additional information
[[Page 27603]]
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
proposed to be 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. 2020 SARs (e.g., Muto et al. 2021). All values presented in
Table 4 are the most recent available at the time of publication and
are available in the 2020 SARs (Muto et al. 2021) and draft 2021 SARs
(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 Proposed To Be 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 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
Minke whale..................... Balaenoptera Alaska................ -, -, N N/A (see SAR, N/A, see UND 0
acutorostrata. SAR).
Family Balaenopteridae (rorquals):
Fin whale....................... Balaenoptera physalus.. Northeastern Pacific.. E, D, Y see SAR (see SAR, see see SAR 0.6
SAR, 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Beluga whale.................... Delphinapterus leucas.. Cook Inlet............ E, D, Y 279 (0.061, 267, 2018) see SAR 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.
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 see SAR 37
SAR, 2015).
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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, 14011 >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.
[[Page 27604]]
As indicated above, all 11 species (with 12 managed stocks) in
Table 4 temporally and spatially co-occur with the activity to the
degree that take could reasonably occur, and we have proposed
authorizing 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.
Gray Whale
The eastern North Pacific stock of gray whales occurring in Cook
Inlet are likely migrating to summer feeding grounds in the Bering,
Chukchi, and Beaufort seas, although some whales are known to feed near
Kodiak Island (Carretta et al. 2014). Gray whales generally breed every
two years during November and December while undertaking the southern
migration (Jones and Swartz 2009). Gray whales have been reported
feeding near Kodiak Island, in southeastern Alaska, and south along the
Pacific Northwest (Allen and Angliss 2013). Most gray whales migrating
through the Gulf of Alaska region are thought to take a coastal route
and (Ferguson et al. 2015) delineated the migratory corridor
biologically important area (BIA) boundaries based on the extent of the
continental shelf.
Most gray whales calve and breed from late December to early
February in protected waters along the western coast of Baja
California, Mexico. In spring, the Eastern North Pacific stock of gray
whales migrates ~8,000 km (5,000 mi) to feeding grounds in the Bering
and Chukchi seas before returning to their wintering areas in the fall
(Rice and Wolman 1971). Northward migration, primarily of individuals
without calves, begins in February; some cow/calf pairs delay their
departure from the calving area until well into April (Jones and Swartz
1984). Gray whales approach the lower Cook Inlet in late March, April,
May, and June, and leave again in November and December (Consiglieri et
al. 1982; Rice and Wolman 1971) but migrate past the mouth of Cook
Inlet to and from northern feeding grounds. Some gray whales do not
migrate completely from Baja to the Chukchi Sea but instead feed in
select coastal areas in the Pacific Northwest, including lower Cook
Inlet (Moore et al. 2007).
Most of the population follows the outer coast of the Kodiak
Archipelago from the Kenai Peninsula in spring or the Alaska Peninsula
in fall (Consiglieri et al. 1982; Rice and Wolman 1971). Though most
gray whales migrate past Cook Inlet, small numbers have been noted by
fishers near Kachemak Bay, and north of Anchor Point (BOEM 2015).
During the NMFS aerial surveys, gray whales were observed in the month
of June in 1994, 2000, 2001, 2005 and 2009 on the east side of Cook
Inlet near Port Graham and Elizabeth Island but also on the west side
near Kamishak Bay (Shelden et al. 2013). One gray whale was sighted as
far north at the Beluga River. Additionally, summering gray whales were
seen offshore of Cape Starichkof by marine mammal observers monitoring
Buccaneer's Cosmopolitan drilling program in 2013 (Owl Ridge 2014).
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, no gray whales
were observed (Kendall et al. 2015). No gray whales were observed
during the 2019 Hilcorp seismic survey in lower Cook Inlet (Fairweather
Science 2020) or during the 2018 Cook Inlet Pipeline (CIPL) project
(Sitkiewicz et al. 2018).
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), 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 one 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 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).
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
[[Page 27605]]
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.
Minke Whale
Minke whales are a non-ESA listed cetacean not commonly found in
the Cook Inlet region. Minke whales are not designated as depleted
under the MMPA or listed as threatened or endangered under the ESA.
Presumably, minke whales breed in warm, low latitude waters during
winter, give birth every other year to one calf, and reach sexual
maturity at 7 to 9 m (23 to 30 ft) in length (Perrin and Brownell
2009). Potential threats to and vulnerabilities of minke whales include
anthropogenic sound emissions underwater, impacts on prey distribution,
climate change, fishing operations, vessel strikes, and oil and gas
operations (Muto et al. 2018).
Minke whales are most abundant in the Gulf of Alaska during summer
and occupy localized feeding areas (Zerbini et al. 2006).
Concentrations of minke whales have occurred along the north coast of
Kodiak Island and along the south coast of the Alaska Peninsula
(Zerbini et al. 2006). The most recent estimate for minke whales
specifically between Kenai Fjords and the Aleutian Islands is 1,233
individuals (Zerbini et al. 2006). No population estimate for minke
whales in the entirety of the north Pacific exists (Muto et al, 2019).
During shipboard surveys conducted in 2003, three minke whale sightings
were made, all near the eastern extent of the survey from nearshore
Prince William Sound to the shelf break (MML, 2003). Minke whales
become scarce in the Gulf of Alaska in fall; most whales are thought to
leave the region by October (Consiglieri et al. 1982). Minke whales are
migratory in Alaska, but recently have been observed off Cape
Starichkof and Anchor Point year-round (Muto et al. 2017).
During Cook Inlet-wide aerial surveys conducted from 1993 to 2004,
minke whales were encountered three times (1998, 1999, and 2006), both
times off Anchor Point 26 km (16 miles [mi]) northwest of Homer
(Shelden et al. 2013, 2015, 2017; Shelden and Wade 2019). A minke whale
was also reported off Cape Starichkof in 2011 and 2013, suggesting this
location is regularly used by minke whales, including during the
winter. Several minke whales were recorded off Cape Starichkof in early
summer 2013 during exploratory drilling (Owl Ridge 2014), suggesting
this location may be used by minke whales year-round. During Apache's
2014 survey, a total of two minke whale groups (totaling three
individuals) were observed during this time period, one sighting to the
southeast of Kalgin Island and another sighting near Homer (Lomac-
MacNair et al. 2014). SAExploration noted one minke whale near Tuxedni
Bay in 2015 (Kendall et al. 2015). There were eight sightings of eight
minke whales observed in the 2019 Hilcorp lower Cook Inlet seismic
survey in the fall (Fairweather Science 2020). This higher number of
minke whales suggests these offshore waters of lower Cook Inlet may be
utilized by minke whales in greater numbers than previously estimated,
particularly during the fall period. No minke whales were observed
during the 2018 CIPL project (Sitkiewicz et al. 2018).
Fin Whale
Fin whales are listed as endangered under the ESA in 1990 and
depleted under the MMPA. For management purposes, three stocks of fin
whales are currently recognized in United States (U.S.) Pacific waters:
Alaska (Northeast Pacific), California/Washington/Oregon, and Hawaii.
Recent analyses provide evidence that the population structure should
be reviewed and possibly updated, however substantially new data on the
stock structure is lacking (Muto et al. 2019).The Northeast Pacific
stock is categorized as a strategic stock. No critical habitat has been
designated or proposed for fin whales in the North Pacific.
Fin whales are usually observed as individuals traveling alone,
although they are sometimes observed in small groups. Rarely, large
groups of 50 to 300 fin whales can travel together during migrations
(NMFS 2010a). Fin whales in the Cook Inlet have only been observed as
individuals or in small groups. Fin whales are vulnerable to natural
and anthropogenic variables. Impacts on prey quality and distribution
could affect distribution and energetics. The natural range of fin
whales could be expanded due to sea ice melting and expanded available
habitat. This could also result in increased exposure to shipping and
other commercial activities. Toxicity and resulting deaths, as seen in
recent years, from harmful algal blooms producing biotoxins could
result from warming waters (Muto et al. 2021).
In the U.S. Pacific waters, fin whales are found seasonally in the
Gulf of Alaska, Bering Sea, and as far north as the northern Chukchi
Sea (Muto et al. 2019). Surveys conducted in coastal waters of the
Aleutians and the Alaska Peninsula found fin whales occurred primarily
from the Kenai Peninsula to the Shumagin Islands and were abundant near
the Semidi Islands and Kodiak Island (Zerbini et al. 2006). An
opportunistic survey conducted on the shelf of the Gulf of Alaska found
fin whales concentrated west of Kodiak Island in Shelikof Strait, and
in the southern Cook Inlet region. In the northeastern Chukchi Sea,
visual sightings and acoustic detections have been increasing, which
suggests the stock may be re-occupying habitat used prior to large-
scale commercial whaling (Muto et al. 2019). Most of these areas are
feeding habitat for fin whales. Watkins et al. (2000), and Stafford et
al. (2007) documented high rates of calling along the Alaska coast
beginning in August/September and lasting through February. Fin whales
are regularly observed in the Gulf of Alaska during the summer months,
even though calls are seldom detected during this period (Stafford et
al. 2007). Instruments moored in the southeast Bering Sea detected
calls over the course of a year and found peaks from September to
November as well as in February and March (Stafford et al. 2010).
Delarue et al. (2013) detected calls in the northeastern Chukchi Sea
from instruments moored from July through October from 2007 through
2010.
Fin whales are rarely observed in Cook Inlet and most sightings
occur near the entrance of the inlet. During the
[[Page 27606]]
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, 2017; Shelden and Wade 2019). There were
eight sightings of 23 fin whales observed in the 2019 Hilcorp lower
Cook Inlet seismic survey in the fall (Fairweather Science 2020). This
higher number of fin whale sightings suggests these offshore waters of
lower Cook Inlet may be utilized by fin whales in greater numbers than
previously estimated, particularly during the fall period.
Beluga Whale
The Cook Inlet beluga whale stock is a small geographically
isolated population that is separated from other beluga populations by
the Alaska Peninsula. The population is genetically distinct from other
Alaska populations suggesting the Peninsula is an effective barrier to
genetic exchange (O'Corry-Crowe et al. 1997). The Cook Inlet beluga
whale population is estimated to have declined from 1,300 animals in
the 1970s (Calkins 1989) to about 340 animals in 2014 (Shelden et al.
2015). The current population estimate is 279 animals (Shelden and Wade
2019). In 1999, beluga hunters agreed to a moratorium on hunting to
protect the species, from 2000 through 2005 one strike per year was
allowed and taken in all but 2004, and since 2006 no Cook Inlet belugas
have been harvested by subsistence users (Muto et al. 2021).
NMFS designated the population as depleted under the MMPA in 2000
and listed it as endangered under the ESA in 2008 when the population
failed to recover following a moratorium on subsistence harvest (65 FR
34590; May 31, 2000). In April 2011, NMFS designated critical habitat
for the beluga under the ESA (76 FR 20180; April 11, 2011). NMFS
finalized the Conservation Plan for the Cook Inlet beluga in 2008 (NMFS
2008a) and the Recovery Plan for Cook Inlet beluga whales in 2016 (NMFS
2016a). During the most recent 10-year time period (2008 to 2018), the
population of Cook Inlet belugas experienced a decline of about 2.3
percent per year (Wade et al. 2019). Threats that have the potential to
impact this stock and its habitat include the following: Changes in
prey availability due to natural environmental variability, ocean
acidification, and commercial fisheries; climatic changes affecting
habitat; predation by killer whales; contaminants; noise; ship strikes;
waste management; urban runoff; construction projects; and physical
habitat modifications that may occur as Cook Inlet becomes increasingly
urbanized (Moore et al., 2000, Lowry et al., 2006, Hobbs et al., 2015,
NMFS, 2106). Planned projects that may alter the physical habitat of
Cook Inlet include highway improvements; mine construction and
operation; oil and gas exploration and development; and expansion and
improvements to ports.
Generally, female beluga whales reach sexual maturity at 9 to 12
years old, while males reach maturity later (O'Corry-Crowe 2009);
however, this can vary between populations. For example, in Greenland,
males in a population of beluga whales were found to reach sexual
maturity at 6 to 7 years of age and females at 4 to 7 years. (Heide-
Joregensen and Teilmann 1994). Suydam (2009) estimated that 50 percent
of females were sexually mature at age 8.25 and the average age at
first birth was 8.27 years for belugas sampled near Point Lay. Mating
behavior in beluga whales typically occurs between February and June,
peaking in March (Burns and Seaman 1986; Suydam 2009). In the Chukchi
Sea, the gestation period of beluga whales was determined to be 14.9
months, with a calving interval of two to three years and a pregnancy
rate of 0.41, declining after 25 years of age (Suydam 2009). Calves are
born between mid-June and mid-July and typically remain with the mother
for up to 2 years of age (Suydam 2009).
Several studies (Johnson et al. 1989; Klishin et al. 2000; Finneran
et al. 2002; Erbe 2008; white et al. 1978; Awbrey et al. 1988; Ridgway
et al. 2001; Finneran et al. 2005; Castellote et al. 2019) describe
beluga whale hearing capabilities. One study on beluga whales captured
and released in Bristol Bay, Alaska measured hearing ranges at 4 to 150
kHz with greatest variation between individuals at the high end of the
auditory range in combination with frequencies near the maximum
sensitivity (Castellote et al. 2014). All animals tested heard well up
to 128 kHz, with two individuals hearing up to 150 kHz (Castellote et
al. 2014). Beluga whales are included in the NMFS-identified mid-
frequency functional hearing group.
The Cook Inlet beluga stock remains within Cook Inlet throughout
the year (Goetz et al. 2012a). Two areas, consisting of 7,809 square
kilometers (km\2\) of marine and estuarine environments considered
essential for the species' survival and recovery, were designated
critical habitat. However, in recent years the range of the beluga
whale has contracted to the upper reaches of Cook Inlet (Rugh et al.
2010). Area 1 of the Cook Inlet beluga whale critical habitat
encompasses all marine waters of Cook Inlet north of a line connecting
Point Possession (61.04[deg] N, 150.37[deg] W) and the mouth of
Threemile Creek (61.08.55[deg] N, 151.04.40[deg] W), including waters
of the Susitna, Little Susitna, and Chickaloon Rivers below the mean
higher high water line (MHHW). This area provides important habitat
during ice-free months and is used intensively by Cook Inlet beluga
between April and November for feeding and other biological functions
(NMFS 2016a).
Since 1993, NMFS has conducted annual aerial surveys in June, July,
or August to document the distribution and abundance of beluga whales
in Cook Inlet. The collective survey results show that beluga whales
have been consistently found near or in river mouths along the northern
shores of middle and upper Cook Inlet. In particular, beluga whale
groups are seen in the Susitna River Delta, Knik Arm, and along the
shores of Chickaloon Bay. Small groups had also been recorded farther
south in Kachemak Bay, Redoubt Bay (Big River), and Trading Bay
(McArthur River) prior to 1996, but very rarely thereafter. Since the
mid-1990s, most beluga whales have been concentrated in shallow areas
near river mouths north and east of Beluga River and Point Possession
(Hobbs et al. 2008). Based on these aerial surveys, there is a
consistent pattern of beluga whale presence in the northernmost portion
of Cook Inlet from June to October (Rugh et al. 2000, 2004a, 2004b,
2005, 2006, 2007).
Though Cook Inlet beluga whales can be found throughout the inlet
at any time of year, generally they spend the ice-free months in the
upper Cook Inlet, shifting into deeper waters in middle Cook Inlet in
winter (Hobbs et al. 2008). In 1999, one beluga whale was tagged with a
satellite transmitter, and its movements were recorded from June
through September of that year. Since 1999, 18 beluga whales in upper
Cook Inlet have been captured and fitted with satellite tags to provide
information on their movements during late summer, fall, winter, and
spring. Using location data from satellite-tagged Cook Inlet belugas,
Ezer et al. (2013) found most tagged whales were in the lower to middle
inlet during January through March, near the Susitna River Delta from
April to July) and in the Knik and Turnagain Arms from August to
December.
During the spring and summer, beluga whales are generally
concentrated near the warmer waters of river mouths where prey
availability is high and predator occurrence is low (Moore et al.
2000). Beluga whales in Cook Inlet are
[[Page 27607]]
believed to mostly calve between mid-May and mid-July, and concurrently
breed between late spring and early summer (NMFS 2016a), primarily in
upper Cook Inlet. Beluga movement was correlated with the peak
discharge of seven major rivers emptying into Cook Inlet. Boat-based
surveys from 2005 to the present (McGuire and Stephens 2017), and
initial results from passive acoustic monitoring across the entire
inlet (Castellote et al. 2016) also support seasonal patterns observed
with other methods, and other surveys confirm Cook Inlet belugas near
the Kenai River during summer months (McGuire and Stephens 2017).
During the summer and fall, beluga whales are concentrated near the
Susitna River mouth, Knik Arm, Turnagain Arm, and Chickaloon Bay
(Nemeth et al. 2007) where they feed on migrating eulachon
(Thaleichthys pacificus) and salmon (Onchorhyncus spp.) (Moore et al.
2000). Data from tagged whales (14 tags between July and March 2000
through 2003) show beluga whales use upper Cook Inlet intensively
between summer and late autumn (Hobbs et al. 2005). Critical Habitat
Area 1 encompasses this summer distribution.
As late as October, beluga whales tagged with satellite
transmitters continued to use Knik Arm and Turnagain Arm and Chickaloon
Bay, but some ranged into lower Cook Inlet south to Chinitna Bay,
Tuxedni Bay, and Trading Bay (McArthur River) in the fall (Hobbs et al.
2005). Data from NMFS aerial surveys, opportunistic sighting reports,
and satellite-tagged beluga whales confirm they are more widely
dispersed throughout Cook Inlet during the winter months (November to
April), with animals found between Kalgin Island and Point Possession.
In November, beluga whales moved between Knik Arm, Turnagain Arm, and
Chickaloon Bay, similar to patterns observed in September (Hobbs et al.
2005). By December, beluga whales were distributed throughout the upper
to middle Cook Inlet. From January into March, they moved as far south
as Kalgin Island and slightly beyond in central offshore waters. Beluga
whales also made occasional excursions into Knik Arm and Turnagain Arm
in February and March despite ice cover greater than 90 percent (Hobbs
et al. 2005). Critical Habitat Area 2 encompasses some of the fall and
winter feeding grounds in middle Cook Inlet.
Ferguson et al. (2015) delineated one `Small' and `Resident' BIA
for Cook Inlet beluga whales. Small and Resident BIAs are defined as
``areas and time within which small and resident populations occupy a
limited geographic extent'' (Ferguson et al. 2015). The Cook Inlet
beluga whale BIA was delineated using the habitat model results of
Goetz et al. 2012 and the critical habitat boundaries and overlaps with
both Critical Habitat Areas 1 and 2.
During Apache's seismic test program in 2011 along the west coast
of Redoubt Bay, lower Cook Inlet, a total of 33 beluga whales were
sighted during the survey (Lomac-MacNair et al. 2013). During Apache's
2012 seismic program in mid-inlet, a total of 151 sightings consisting
of an estimated 1,463 beluga whales were observed (Lomac-MacNair et al.
2014). During SAExploration's 2015 seismic program, a total of eight
sightings of 33 estimated individual beluga whales were visually
observed during this time period and there were two acoustic detections
of beluga whales (Kendall et al. 2015). During Harvest Alaska's recent
CIPL project on the west side of Cook Inlet in between Ladd Landing and
Tyonek Platform, a total of 143 beluga whale sightings (814
individuals) were observed almost daily from May 31 to July 11, even
though observations spanned from May 9 through September 15 (Sitkiewicz
et al. 2018). There were two beluga whale carcasses observed by the
project vessels in the 2019 Hilcorp lower Cook Inlet seismic survey in
the fall which were reported to the NMFS Marine Mammal Stranding
Network (Fairweather Science 2020). Both carcasses were moderately
decomposed when they were sighted by the PSOs. Daily aerial surveys
specifically for beluga whales were flown over the lower Cook Inlet
region, but no beluga whales were observed.
Killer Whale
Based on data regarding association patterns, acoustics, movements,
and genetic differences, eight killer whale stocks are now recognized
within the Pacific U.S. Exclusive Economic Zone. Two different stocks
of killer whales inhabit the Cook Inlet region of Alaska: The Alaska
Resident Stock and the Gulf of Alaska, Aleutian Islands, Bering Sea
Transient Stock (Muto et al. 2021). The Alaska Resident Stock and the
Gulf of Alaska, Aleutian Islands, Bering Sea Transient Stock of killer
whales are not designated as depleted under the MMPA or listed as
threatened or endangered under the ESA. Reliable data on population
trends for these killer whale stocks are unavailable (Muto et al.
2021).
Resident and transient killer whales from the Alaska Resident Stock
and the Gulf of Alaska, Aleutian Islands, and Bering Sea Transient
Stock occur in Cook Inlet (Allen and Angliss 2015), though rarely in
middle and upper Cook Inlet. Transient killer whales feed on beluga
whales and other marine mammals, and resident populations feed on
anadromous fish (Shelden et al. 2003). The likelihood of killer whale
occurrence depends on prey availability (NOAA 2019). Threats to and
vulnerabilities of killer whales include natural causes, such as
predation, and anthropogenic factors such as climate change, fishing
operations and vessel strikes (Muto et al. 2016).
Killer whales are occasionally observed in lower Cook Inlet,
especially near Homer and Port Graham (Shelden et al. 2003; Rugh et al.
2005). The few whales that have been photographically identified in
lower Cook Inlet belong to resident groups more commonly found in
nearby Kenai Fjords and Prince William Sound (Shelden et al. 2003). The
availability of prey species largely determines the likeliest times for
killer whales to be in the area. During aerial surveys conducted
between 1993 and 2004, killer whales were observed on only three
flights, all in the Kachemak and English Bay area (Rugh et al. 2005).
However, anecdotal reports of killer whales feeding on belugas in
middle and upper Cook Inlet began increasing in the 1990s, possibly in
response to declines in sea lion and harbor seal prey elsewhere
(Shelden et al. 2003).
One killer whale group of two individuals was observed during the
2015 SAExploration seismic program near the North Foreland (Kendall et
al. 2015). During NMFS aerial surveys, killer whales were observed in
1994 (Kamishak Bay), 1997 (Kachemak Bay), 2001 (Port Graham), 2005
(Iniskin Bay), 2010 (Elizabeth and Augustine Islands), and 2012
(Kachemak Bay; Shelden et al. 2013). Eleven killer whale strandings
have been reported in Turnagain Arm, six in May 1991, and five in
August 1993. There were six sightings of 21 killer whales observed in
the 2019 Hilcorp lower Cook Inlet seismic survey in the fall
(Fairweather Science 2020). This species is expected to be rarely seen
in upper Cook Inlet but may be encountered in the middle and lower
Inlet. However, no killer whales were observed during the 4-month CIPL
project in middle Cook Inlet in 2018 (Sitkiewicz et al. 2018).
Harbor Porpoise
In Alaskan waters, three stocks of harbor porpoises are currently
recognized for management purposes: Southeast Alaska, Gulf of Alaska,
and Bering Sea Stocks (Muto et al. 2019). Porpoises found in Cook Inlet
belong to the Gulf of Alaska Stock which is distributed from Cape
Suckling to
[[Page 27608]]
Unimak Pass and most recently was estimated to number 31,046
individuals (Muto et al. 2019). Harbor porpoises are regularly seen
throughout Cook Inlet (Nemeth et al. 2007), especially during spring
eulachon and summer salmon runs. Harbor porpoises are not designated as
depleted under the MMPA or listed as threatened or endangered under the
ESA.
Harbor porpoises primarily frequent the coastal waters of the Gulf
of Alaska and Southeast Alaska (Dahlheim et al. 2000, 2008), typically
occurring in waters less than 100 m deep (Hobbs and Waite 2010). The
range of the Gulf of Alaska stock includes the entire Cook Inlet,
Shelikof Strait, and the Gulf of Alaska. Harbor porpoises have been
reported in lower Cook Inlet from Cape Douglas to the West Foreland,
Kachemak Bay, and offshore (Rugh et al. 2005). Although they have been
frequently observed during aerial surveys in Cook Inlet (Shelden et al.
2014), most sightings are of single animals, and are concentrated at
Chinitna and Tuxedni bays on the west side of lower Cook Inlet (Rugh et
al. 2005) and in the upper inlet. The occurrence of larger numbers of
porpoise in the lower Cook Inlet may be driven by greater availability
of preferred prey and possibly less competition with beluga whales, as
belugas move into upper inlet waters to forage on Pacific salmon
(Oncorhynchus spp.) during the summer months (Shelden et al. 2014).
Recent passive acoustic research in Cook Inlet by Alaska Department of
Fish and Game (ADF&G) and MML have indicated that harbor porpoises
occur more frequently than expected, particularly in the West Foreland
area in the spring (Castellote et al. 2016).
The harbor porpoise frequently has been observed during summer
aerial surveys of Cook Inlet, with most sightings of individuals
concentrated at Chinitna and Tuxedni Bays on the west side of lower
Cook Inlet (Rugh et al. 2005). Mating likely occurs from June or July
to October, with peak calving in May and June (Consiglieri et al.
1982). Small numbers of harbor porpoises have been consistently
reported in the upper Cook Inlet between April and October, except for
a recent survey that recorded higher numbers than typical. NMFS aerial
surveys have routinely identified many harbor porpoise sightings
throughout Cook Inle. During Apache's 2012 seismic program, 137
sightings (190 individuals) were observed between May and August
(Lomac-MacNair et al. 2013). Lomac-MacNair et al. 2014 identified 77
groups of harbor porpoise totaling 13 individuals during Apache's 2014
seismic survey, both from vessels and aircraft, during the month of
May. During SAExploration's 2015 seismic survey, 52 sightings (65
individuals) were observed north of the Forelands (Kendall et al.
2015). There were 2 sightings of 3 harbor porpoises observed during the
2019 Hilcorp lower Cook Inlet seismic survey in the fall (Fairweather
Science 2020). A total of 29 sightings (44 individuals) were observed
north of the Forelands from May to September during the Harvest Alaska
CIPL project (Sitkiewicz et al. 2018). During jack-up rig moves in
2021, a Protected Species Observer (PSO) observed two individual harbor
porpoises in middle Cook Inlet, one in July and one in October.
Dall's Porpoise
Dall's porpoises are widely distributed across the North Pacific,
but they are infrequently sighted in upper Cook Inlet (Muto et al.
2020). Dall's porpoises have been observed in lower Cook Inlet, around
Kachemak Bay, and rarely near Anchor Point (BOEM 2015). Dall's
porpoises are not designated as depleted under the MMPA or listed as
threatened or endangered under the ESA (Muto et al. 2019). Threats to
and vulnerabilities of Dall's porpoises include natural and
anthropogenic factors such as habitat modifications and climate change.
The nearshore areas, bays, channels, and inlets where Dall's porpoises
frequent are of particular concern. These areas are subject to
substantial changes with urbanization and industrialization, including
waste management and nonpoint source runoff (Linnenschmidt et al.
2013).
Throughout most of the eastern North Pacific they are present
during all months of the year, although there may be seasonal onshore-
offshore movements along the west coast of the continental U.S. and
winter movements of populations out of areas with ice such as Prince
William Sound (Muto et al. 2019). No Dall's porpoises were observed
during the CIPL project monitoring program in middle Cook Inlet in 2018
(Sitkiewicz et al. 2018). Dall's porpoises were observed (two groups of
three individuals) during Apache's 2014 seismic survey which occurred
in the summer months (Lomac-MacNair et al. 2014). Dall's porpoises were
observed during the month of June in 1997 (Iniskin Bay), 199 (Barren
Island), and 2000 (Elizabeth Island, Kamishak Bay and Barren Island)
(Shelden et al. 2013). Dall's porpoises have been observed in lower
Cook Inlet, including Kachemak Bay and near Anchor Point (Owl Ridge
2014). One Dall's porpoise was observed in August north of Nikiski in
the middle of the Inlet during SAExploration's 2015 seismic program
(Kendall et al. 2015). There were 10 sightings of 30 Dall's porpoises
observed during the 2019 Hilcorp lower Cook Inlet seismic survey in the
fall (Fairweather Science 2020).
Steller Sea Lion
The Western DPS of Steller sea lions is currently listed as
endangered under the ESA (55 FR 49204; November 26, 1990) and
designated as depleted under the MMPA. Critical habitat was designated
on August 27, 1993 (58 FR 45269; August 27, 1993) south of the proposed
action area in the Cook Inlet region. The critical habitat designation
for the Western DPS of Steller sea lions includes a 37 km buffer around
all major haul outs and rookeries, and associated terrestrial,
atmospheric, and aquatic zones, plus three large offshore foraging
areas, as well as designated no entry zones around rookeries (50 CFR
223.202). Designated critical habitat is located outside Cook Inlet at
Gore Point, Elizabeth Island, Perl Island, and Chugach Island (NMFS
2008b). The Western DPS of the Steller sea lion is defined as all
populations west of longitude 144[deg] W to the western end of the
Aleutian Islands.
Steller sea lions are not migratory animals but exhibit wide
dispersion in the non-breeding season (Loughlin 1997). They are
polygynous in nature, with one male typically breeding with large
numbers of females. Steller sea lions tend to haul out in large groups.
Underwater vocalizations of Steller sea lions have been noted to
include belches, barks, and clicks (Kastelein et al. 2005). Audiograms
have revealed a maximum underwater hearing sensitivity at 77 dB RL at
1kHz for a male Steller sea lion, with a range of best hearing at 10 dB
from the maximum sensitivity, of between 1 and 16 kHz. His average pre-
stimulus responses occurred at low frequency signals. Similar
audiograms of a female Steller sea lion revealed a maximum hearing
sensitivity of 73 dB received level, occurring at 25 kHz, indicating
that low frequency sounds are audible to Steller sea lions (Kastelein
et al. 2005).
Steller sea lions feed largely on walleye pollock (Theragra
chalcogramma), salmon (Onchorhyncus spp.), and arrowtooth flounder
(Atheresthes stomias) during the summer, and walleye pollock and
Pacific cod (Gadus macrocephalus) during the winter (Sinclair and
Zeppelin 2002). Except for salmon, these species are not found in
[[Page 27609]]
abundance in upper Cook Inlet (Nemeth et al. 2007). Threats to and
vulnerabilities of Steller sea lions include natural and anthropogenic
factors, including depletion of prey availability from fishing
activities, climate change, disease, contaminants, predation by killer
whales, incidental take, and illegal and legal shooting (Atkinson et
al. 2008, NMFS 2008), harmful algal blooms (Lefebvre et al. 2016),
disease proliferation from warming waters (VanWormer et al. 2019), and
potentially metal and contaminant exposure (Rea et al. 2013; Beckmen et
al. 2016, Keogh et al. 2020).
Steller sea lions inhabit lower Cook Inlet, especially near Shaw
Island and Elizabeth Island (Nagahut Rocks) haul out sites (Rugh et al.
2005) but are rarely seen in upper Cook Inlet (Nemeth et al. 2007).
Steller sea lions occur in Cook Inlet but south of Anchor Point around
the offshore islands and along the west coast of the upper inlet in the
bays (Chinitna Bay, Iniskin Bay, etc.) (Rugh et al. 2005). Portions of
the southern reaches of the lower inlet are designated as critical
habitat, including a 37 km (20 nautical mile) buffer around all major
haul out sites and rookeries. Rookeries and haul out sites in lower
Cook Inlet include those near the mouth of the inlet, which are far
south of the Action Area.
Steller sea lions have been observed during marine mammal surveys
conducted in Cook Inlet. In 2012, during Apache's 3D Seismic surveys,
there were three sightings of approximately four individuals in upper
Cook Inlet (Lomac-MacNair et al. 2013). Marine mammal observers
associated with Buccaneer's drilling project off Cape Starichkof
observed seven Steller sea lions during the summer of 2013 (Owl Ridge
2014). During SAExploration's 3D Seismic Program in 2015, four Steller
sea lions were observed in Cook Inlet. One sighting occurred between
the West and East Forelands, one near Nikiski and one northeast of the
North Foreland in the center of Cook Inlet (Kendall et al. 2015). There
were five sightings of five Steller sea lions observed during the 2019
Hilcorp lower Cook Inlet seismic survey in the fall (Fairweather
Science 2020). One sighting of two individuals occurred during the CIPL
project in 2018 in middle Cook Inlet (Sitkiewicz et al. 2018). During
NMFS Cook Inlet beluga whale aerial surveys from 2000 to 2016, there
were 39 sightings of 769 estimated individual Steller sea lions in
lower Cook Inlet (Shelden et al. 2017). Sightings of large
congregations of Steller sea lions during NMFS aerial surveys occurred
outside the Action Area, on land in the mouth of Cook Inlet (e.g.,
Elizabeth and Shaw Islands).
California Sea Lion
California sea lions in the U.S. are not listed as endangered or
threatened under the ESA or as depleted or strategic under the MMPA.
The growth rate of the species is approximately seven percent annually
(Carretta et al. 2020). There is limited information on the presence of
California sea lions in Alaska. California sea lion presence in Alaska
was correlated with increasing population numbers within their southern
breeding range (Maniscalco et al. 2004). California sea lions are not
commonly observed in Alaska. When they are observed, they are often
alone or, less commonly, in groups of two or more. They are most often
associated with Steller sea lions at their haulouts and rookeries
(Maniscalco et al. 2004). Threats to and vulnerabilities of California
sea lions include natural and anthropogenic factors including climate
change, exposure to harmful algal neurotoxins (Scholin et al. 2000,
Brodie et al. 2006, Ramsdell and Zabka 2008), shootings, entrainment in
industrial facilities, fishing gear interactions, vessel strikes, and
human disturbance (Muto et al. 2019).
California sea lions are not typically observed farther north than
southeast Alaska, and sightings are very rare in Cook Inlet. California
sea lions have not been observed during the annual NMFS aerial surveys
in Cook Inlet. However, a sighting of two California sea lions was
documented during the Apache 2012 seismic survey (Lomac-MacNair et al.
2013). Additionally, NMFS' anecdotal sighting database has four
sightings in Seward and Kachemak Bay. There were no California sea
lions observed during the 2019 Hilcorp lower Cook Inlet seismic survey
(Fairweather Science 2020) or the CIPL project in 2018 (Sitkiewicz et
al. 2018).
Harbor Seal
In 2010, NMFS and their co-management partners, the Alaska Native
Harbor Seal Commission, defined 12 separate stocks of harbor seals
based largely on genetics. The harbor seal stocks present in the action
area are from the Cook Inlet/Shelikof stock. No harbor seal stocks in
Alaska are designated as depleted under the MMPA or listed as
threatened or endangered under the ESA (Muto et al. 2019).
In Cook Inlet, large harbor seal haulout areas are located in lower
Cook Inlet, with occurrence in upper inlet coinciding with prey
availability. Harbor seals frequent the Susitna River and other rivers
feeding into upper Cook Inlet when eulachon and salmon are migrating in
those areas (NMFS, 2003). Harbor seals haul out on rocks, reefs,
beaches, and drifting glacial ice. Prey species include capelin,
eulachon, cod, pollock, flatfish, shrimp, octopus, and squid. Threats
to and vulnerabilities of harbor seals include natural and
anthropogenic factors including climate change, shipping, and tour
vessel traffic (Muto et al. 2021).
The major haul out sites for harbor seals are located in lower Cook
Inlet and their presence in middle and upper Cook Inlet is seasonal. In
Cook Inlet, seal use of western habitats is greater than use of the
eastern coastline (Boveng et al. 2012). NMFS has documented a strong
seasonal pattern of more coastal and restricted spatial use during the
spring and summer for breeding, pupping, and molting, and more wide-
ranging seal movements within and outside of Cook Inlet during the
winter months (Boveng et al. 2012). Large-scale movement patterns
indicate a portion of harbor seals captured in Cook Inlet move out of
the area in the fall, and into habitats within Shelikof Strait,
Northern Kodiak Island, and coastal habitats of the Alaska Peninsula,
and are most concentrated in Kachemak Bay, across Cook Inlet toward
Iniskin and Iliamna Bays, and south through the Kamishak Bay, Cape
Douglas, and Shelikof Strait regions (Boveng et al. 2012).
The Cook Inlet/Shelikof Stock is distributed from Anchorage into
lower Cook Inlet during summer and from lower Cook Inlet through
Shelikof Strait to Unimak Pass during winter (Boveng et al. 2012).
Large numbers concentrate at the river mouths and embayments of lower
Cook Inlet, including the Fox River mouth in Kachemak Bay, and several
haul outs have been identified on the southern end of Kalgin Island in
lower Cook Inlet (Rugh et al. 2005; Boveng et al. 2012). Montgomery et
al. (2007) recorded over 200 haul-out sites in lower Cook Inlet alone.
NMFS aerial surveys have routinely identified many harbor seal
sightings throughout Cook Inlet over the past 20 years of survey
effort. During Apache's 2012 seismic program, harbor seals were
observed in the project area from early May until the end of the
seismic operations in late September (Lomac-MacNair et al. 2013). Up to
100 harbor seals were observed hauled out at the mouths of the Theodore
and Lewis rivers during monitoring activity. During Apache's 2014
seismic program, 492 groups of harbor seals (613 individuals) were
observed; this highest sighting rate of any marine mammal
[[Page 27610]]
observed during the summer of 2014 (Lomac-MacNair et al. 2014). During
SAExploration's 2015 seismic survey, 823 sightings (1,680 individuals)
were observed north and between the Forelands (Kendall et al. 2015).
Recently, a total of 313 sightings (316 individuals) were observed near
Ladd Landing for the Harvest Alaska CIPL project during the summer
(Sitkiewicz et al. 2018). There were 10 sightings of 10 harbor seals
observed during the 2019 Hilcorp lower Cook Inlet seismic survey in the
fall (Fairweather Science 2020). During a Hilcorp jack-up rig move in
2021, one pinniped of an unidentified species was observed in July in
middle Cook Inlet.
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.
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
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
The proposed project includes the use of three tugs towing a jack-
up rig, which would emit consistent, low levels of noise into a small
portion of Cook Inlet for an extended period of time. Hilcorp's tugging
and positioning activities would occur for approximately 16 days in
Year 1 and 16 days in Year 2 to support overall production and well
plug and abandonment operations that would occur across 210 days in
Year 1 and 180 days in Year 2. Unlike projects that involve discrete
noise sources with known potential to harass marine mammals (e.g., pile
driving, seismic surveys), both the noise sources and impacts from the
tugs towing the jack-up rig are less well documented. In light of the
aforementioned court decision we have re-examined the available
information. The various scenarios that may occur during this project
extend from tugs in a stationary mode, positioning the drill rig to
pulling the jack-up rig at nearly full power against strong tides. Our
assessments of the potential for harassment of marine mammals
incidental to Hilcorp's tug activities specified here are conservative
in light of the general Level B harassment exposure thresholds, the
fact that NMFS is still in the process of developing analyses of the
impact that non-quantitative contextual factors have on the likelihood
of Level B harassment occurring, and the nature and duration of the
particular tug activities analyzed here.
The proposed project has the potential to harass marine mammals
from exposure to noise and the physical presence of working vessels
(e.g., three tug configuration) as well as associated noise with the
positioning of the jack-up rig. In this case, NMFS considers potential
for harassment from the collective use of these technologies working in
a concentrated area (relative to the entire Cook Inlet) for an extended
period of time (when making multiple positioning attempts) and noise
created when moving the jack-up rig using three tugs. Essentially, the
project area will become a concentrated work area in an otherwise non-
industrial setting for a period of several days. Accordingly the
Estimated Take section proposes to authorize take, by Level B
harassment,
[[Page 27611]]
from tug towing activities over the course of 16 days of activity each
year.
Auditory Effects
NMFS defines a noise-induced threshold shift (TS) as ``a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level'' (NMFS, 2018). The amount of
threshold shift is customarily expressed in dB (ANSI 1995, Yost 2007).
A TS can be permanent (PTS) or temporary (TTS). As described in NMFS
(2016), there are numerous factors to consider when examining the
consequence of TS, including, but not limited to, the signal temporal
pattern (e.g., impulsive or non-impulsive), likelihood an individual
would be exposed for a long enough duration or to a high enough level
to induce a TS, the magnitude of the TS, time to recovery (seconds to
minutes or hours to days), the frequency range of the exposure (i.e.,
spectral content), the hearing and vocalization frequency range of the
exposed species relative to the signal's frequency spectrum (i.e., how
animal uses sound within the frequency band of the signal; e.g.,
Kastelein et al., 2014), and the overlap between the animal and the
source (e.g., spatial, temporal, and spectral). When analyzing the
auditory effects of noise exposure, it is often helpful to broadly
categorize sound as either impulsive--noise with high peak sound
pressure, short duration, fast rise-time, and broad frequency content--
or non-impulsive. For example, when considering auditory effects,
vibratory pile driving is considered a non-impulsive source while
impact pile driving is treated as an impulsive source. The sounds
produced by tugs towing and positioning the jack-up rig are
characterized as non-impulsive sounds.
Permanent Threshold Shift--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). Available data from
humans and other terrestrial mammals indicate that a 40 dB threshold
shift approximates PTS onset (see NMFS 2018 for review).
Temporary Threshold Shift--NMFS defines TTS as a temporary,
reversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). Based on data from
cetacean TTS measurements (see Finneran 2015 for a review), a TTS of 6
dB is considered the minimum threshold shift clearly larger than any
day-to-day or session-to-session variation in a subject's normal
hearing ability (Schlundt et al., 2000; Finneran et al., 2002;
Finneran, 2015).
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during times when hearing
is critical, such as for successful mother/calf interactions, could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Masking
Since many marine mammals rely on sound to find prey, moderate
social interactions, and facilitate mating (Tyack, 2008), noise from
anthropogenic sound sources can interfere with these functions, but
only if the noise spectrum overlaps with the hearing sensitivity of the
marine mammal (Southall et al., 2007; Clark et al., 2009; Hatch et al.,
2012). Chronic exposure to excessive, though not high-intensity, noise
could cause masking at particular frequencies for marine mammals that
utilize sound for vital biological functions (Clark et al., 2009).
Acoustic masking is when other noises such as from human sources
interfere with animal detection and/or interpretation of acoustic
signals such as communication calls, echolocation sounds, and
environmental sounds important to marine mammals. Therefore, under
certain circumstances, marine mammals whose acoustical sensors or
environment are being severely masked could also be impaired from
maximizing their performance fitness in survival and reproduction.
Masking occurs in the frequency band that the animals utilize.
Since noises generated from tugs towing and positioning are mostly
concentrated at low frequency ranges, with a small concentration in
high frequencies as well, these activities likely have less effect on
mid-frequency echolocation sounds by odontocetes (toothed whales) such
as Cook Inlet beluga whales. However, lower frequency noises are more
likely to affect detection of communication calls and other potentially
important natural sounds such as surf and prey noise. Low-frequency
noise may also affect communication signals when they occur near the
noise band and thus reduce the communication space of animals (e.g.,
Clark et al., 2009) and cause increased stress levels (e.g., Holt et
al., 2009). Unlike TS, masking, which can occur over large temporal and
spatial scales, can potentially affect the species at population,
community, or even ecosystem levels, in addition to individual levels.
Masking affects both senders and receivers of the signals and at higher
levels for longer durations could have long-term chronic effects on
marine mammal species and populations. However, the noise generated by
the tugs will not be concentrated in one location or for more than five
hours per day and in the same geographic location for only two days per
well site.
Behavioral Disturbance
Finally, exposure of marine mammals to certain sounds could result
in behavioral disturbance (Richardson et al., 1995), not all of which
constitutes harassment under the MMPA. The onset of behavioral
disturbance from anthropogenic noise depends on both external factors
(e.g., characteristics of noise sources and their paths) and the
receiving animals (e.g., hearing, behavioral state, experience,
demography) and is difficult to predict (Southall et al., 2007, 2021).
Currently NMFS uses a received level of 160 dB re 1 micro Pascal
([mu]Pa) root mean square (rms) to predict the onset of behavioral
harassment from impulse noises (such as impact pile driving), and 120
dB re 1 [mu]Pa (rms) for continuous noises (such as operating dynamic
positioning (DP) thrusters), although in certain circumstances there
may be contextual factors that alter our assessment of the onset of
behavioral harassment. No impulsive noise within the hearing range of
marine mammals is expected from Hilcorp's proposed activities. For the
tug towing and positioning activities, only the 120 dB re 1 [mu]Pa
(rms) threshold is considered because only continuous noise sources
would be generated.
Disturbance may result in changing durations of surfacing and
dives, number of blows per surfacing, moving
[[Page 27612]]
direction and/or speed, reduced/increased vocal activities; changing/
cessation of certain behavioral activities (such as socializing or
feeding), visible startle response or aggressive behavior (such as
tail/fluke slapping or jaw clapping), avoidance of areas where sound
sources are located, and/or flight responses. Pinnipeds may increase
their haul-out time, possibly to avoid in-water disturbance (Thorson
and Reyff 2006). These potential behavioral responses to sound are
highly variable and context-specific and reactions, if any, depend on
species, state of maturity, experience, current activity, reproductive
state, auditory sensitivity, time of day, and many other factors
regarding the source eliciting the response (Richardson et al., 1995;
Wartzok et al., 2004; Southall et al., 2007). For example, animals that
are resting may show greater behavioral change in response to
disturbing sound levels than animals that are highly motivated to
remain in an area for feeding (Richardson et al., 1995; NRC 2003;
Wartzok et al., 2004). The biological significance of many of these
behavioral disturbances is difficult to predict, especially if the
detected disturbances appear minor. However, the consequences of
behavioral modification could be biologically significant if the change
affects growth, survival, and/or reproduction, which depends on the
severity, duration, and context of the effects.
In consideration of the range of potential effects (PTS to
behavioral disturbance), we consider the potential exposure scenarios
and context in which species would be exposed to tug-related activity.
Cook Inlet beluga whales may be present in low numbers during the work;
therefore, some individuals may be reasonably expected to be exposed to
elevated sound levels, including briefly those that exceed the Level B
harassment threshold for continuous noise. However, beluga whales are
expected to be transiting through the area, given this work is proposed
primarily in middle Cook Inlet (as described in the Description of
Marine Mammals in the Area of Specified Activities section), thereby
limiting exposure duration, as belugas in the area are expected to be
headed to or from the concentrated foraging areas farther north near
the Beluga River, Susitna Delta, and Knik and Turnigan Arms. Similarly,
humpback whales, fin whales, minke whales, killer whales, California
sea lion, and Steller sea lions are not expected to remain in the area
of the tugs. Dall's porpoise, harbor porpoise, and harbor seal have
been sighted with more regularity than many other species during oil
and gas activities in Cook Inlet but due to the transitory nature of
porpoises, they are unlikely to remain at any particular well site for
the full duration of the noise-producing activity. Because of this and
the relatively low-level sources, the likelihood of PTS and TTS over
the course of the tug activities is discountable. Harbor seals may
linger or haul-out in the area but they are not known to do so in any
large number or for extended periods of time (there are no known major
haul-outs or rookeries coinciding with the well sites). Here we find
there is small potential for TTS over the course of tug activities but
again, PTS is not likely due to the types of sources involved in the
project.
Given most marine mammals are likely transiting through the area,
exposure is expected to be brief but, in combination with the actual
presence of the tug and jack-up rig configuration, may result in
animals shifting pathways around the work site (e.g., avoidance),
increasing speed or dive times, or cessation of vocalizations. The
likelihood of no more than a short-term, localized disturbance response
is supported by data indicating belugas regularly pass by
industrialized areas such as the Port of Anchorage; therefore, we do
not expect abandonment of their transiting route or other disruptions
of their behavioral patterns. We also anticipate some animals may
respond with such mild reactions to the project that the response would
not be detectable. For example, during low levels of power output
(e.g., while tugs may be operating at low power because of favorable
conditions), the animals may be able to hear the work but any resulting
reactions, if any, are not expected to rise to the level of take.
While in some cases marine mammals have exhibited little to no
obviously detectable response to certain common or routine
industrialized activity (Cornick et al, 2011), it is possible some
animals may at times be exposed to received levels of sound above the
Level B harassment threshold. This potential 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) means it is
possible that take could occur over the total estimated period of tug
activities; therefore, NMFS in response to Hilcorp's IHA application
proposes to authorize take by Level B harassment from Hilcorp's use of
tugs towing a jack-up rig for both positioning and straight-line tug
activities.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers'' and the negligible impact
determinations.
Harassment is the only type of take 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 proposed to be authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) Acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level
[[Page 27613]]
B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance 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
harassed in a manner considered to be Level B harassment when exposed
to underwater anthropogenic noise above root-mean-squared pressure
received levels (RMS SPL) of 120 dB (referenced to 1 micropascal (re 1
[mu]Pa)) for continuous (e.g., vibratory pile-driving, drilling) and
above RMS SPL, 160 dB re 1 [mu]Pa (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
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 proposed 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 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that 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 the 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 [micro]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 proposed 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
[[Page 27614]]
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.
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 five-hour exposure
to a broadband spectrum of 185 dB as described above. A five-hour
exposure duration was chosen to account for the up to five-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.
[[Page 27615]]
[GRAPHIC] [TIFF OMITTED] TN09MY22.031
The outputs of the mobile and stationary models as distances to the
relevant threshold (in meters) are presented below in Tables 7-9.
[[Page 27616]]
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
----------------------------------------------------------------------------------------------------------------
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 MML
aerial surveys, typically flown in June,
[[Page 27617]]
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 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
Species (indiv/
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
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
Project location density (ind/
km\2\)
------------------------------------------------------------------------
North Cook Inlet Unit (middle Cook Inlet)............... 0.001664
Trading Bay Area........................................ 0.004453-0.015
053
------------------------------------------------------------------------
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, five hours of
sound production per day was assumed for up to 16 days (eight moves or
segments consisting of two days each). For the mobile portion of the
activity, two days of nine hours of mobile activity (assuming a source
velocity of 2.06 m/s) and six days of six hours of mobile activity were
assumed, for a total of eight rig moves.
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. The calculated exposures for Years 1 and 2
are identical, as the number of days and hours of expected tug noise is
ultimately the same despite the different divisions of the activity
(e.g. Year 1 has tug noise from P&A, Year 2 does not have P&A but has
more overall tugging trips). 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 California sea lions because the assumed density is 0.00 animals/
km\2\.
Table 12--Total Calculated Exposures for Year 1
----------------------------------------------------------------------------------------------------------------
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 10.345
[[Page 27618]]
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
----------------------------------------------------------------------------------------------------------------
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
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 does not propose to
authorize 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 five 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 two days, the occurrence of PTS is unlikely. A table
indicating the number of takes, by Level B harassment, proposed to be
authorized is provided below.
Table 14--Takes (by Level B Harassment) Calculated and Proposed To Be Authorized for Year 1 IHA and Year 2 IHA
----------------------------------------------------------------------------------------------------------------
Year 1 Year 1 Year 2 Year 2
calculated authorized calculated authorized
----------------------------------------------------------------------------------------------------------------
Humpback whale.................................. 4.058 6 4.058 6
Minke whale..................................... 0.021 6 0.021 6
Gray whale...................................... 0.171 2 0.171 2
Fin whale....................................... 0.712 4 0.712 4
Killer whale.................................... 1.379 10 1.379 10
Beluga whale.................................... 2.545 (MML) 22 2.545 (MML) 22
10.345 (Goetz) 11.651 (Goetz)
Dall's porpoise................................. 0.353 6 0.353 6
Harbor porpoise................................. 10.057 44 10.057 44
Harbor seal..................................... 553.565 554 553.565 554
Steller sea lion................................ 17.448 17 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 proposed to be 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 is requesting six takes of humpback whales to
allow for up to two sightings of three individuals, consistent with
what was observed during the CIPL project. Minke whale takes proposed
to be 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
[[Page 27619]]
requesting six takes of minke whale to allow for the possibility of two
sightings of a group of three individuals. 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. The number
of fin whale takes proposed to be 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.
The number of proposed killer whale takes is increased to ten 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 two to five individuals (Fairweather 2020). Based on
documented sightings, Hilcorp requests ten takes of killer whales to
allow for two sightings with a group size of five individuals.
Depending on the density data used for each activity, the estimated
annual exposures for beluga whales is three to 10 animals. The proposed
number of takes to be authorized for beluga whales is 22 animals 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 (two to 147
whales) as was the case in previous survey years (Boyd et al. 2019).
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 proposed to be
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 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. Harbor porpoise takes are proposed to be
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 and the inability to shut down the tugs,
Hilcorp request 44 takes of harbor porpoise, commensurate with the
number observed in the nearby CIPL project.
Calculated take of California sea lions was zero because the
assumed density in Cook Inlet is zero. Any potential sightings would
likely be of 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 requested 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.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses. 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
7 km in all directions along a towing trajectory of approximately 37km.
There is a
[[Page 27620]]
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
and there is no designated shut-down/exclusion zone proposed for this
project. However, Hilcorp will implement a number of mitigation
measures designed to reduce the potential for and severity of Level B
harassment and minimize the acoustic footprint of the project.
The tugs towing a jack-up rig are not able to shutdown 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 proposes to 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 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. 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., Armasight by
FLIR Command Pro[supreg], 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 high-high
water line of the Susitna River Delta (Beluga River to the Little
Susitna River) between April 15 and October 15.
Based on our evaluation of the applicant's proposed measures, for
both IHAs, NMFS has preliminarily determined that the proposed
mitigation measures provide the means of effecting the least
practicable impact on the affected species or stocks and their habitat,
paying particular attention to rookeries, mating grounds, and areas of
similar significance and on the availability of such species or stock
for subsistence uses.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed 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 February 25, 2022. A summary of those measures and additional
requirements proposed 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
[[Page 27621]]
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);
(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
construction operation 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 in-water construction activities were
conducted; dates and times when in-water construction activities were
suspended to avoid potential incidental injury from construction sound
of marine mammals observed within a defined shutdown zone; 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 four hours without a minimum of a one 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
pile driving activity;
<bullet> Distance from pile driving 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),
Hilcorp 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 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
[[Page 27622]]
listed in Table 15, given that the anticipated effects of this activity
on these different marine mammal stocks are expected to be similar.
There is little information about the nature or severity of the
impacts, or the size, status, or structure of any of these species or
stocks that would lead to a different analysis for this activity.
To avoid repetition, this introductory section of our analysis
applies to all the species listed in Table 15, given that many of the
anticipated effects of this project on different marine mammal stocks
are expected to be relatively similar in nature. Where there are
meaningful differences between species or stocks, or groups of species,
in anticipated individual responses to activities, impact of expected
take on the population due to differences in population status, or
impacts on habitat, they are described independently in the analysis
below.
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 the proposed activity
is small relative to the overall distribution of the animals in the
area and their use of the area. 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.
The proposed project would create an acoustic footprint around the
project area for a total of sixteen days per year from approximately
April through October. 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 45km\2\ around the tugs positioning the jackup rig or
approximately 7 km in all directions along a towing trajectory of
approximately 37 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. Animals may swim around the
project area but we do not expect them to abandon any intended path. 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 operational
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.
In summary and as described above, the following factors primarily
support our preliminary 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 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;
<bullet> Exposure would likely be brief given transiting behavior
of marine mammals in the action area;
<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 would 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 proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity described in the Year 1 IHA will
have a negligible impact on all affected marine mammal species or
stocks. Also, separately, NMFS preliminarily finds that the total
marine mammal take from the proposed 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 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 proposed represents less than approximately
two percent of the population for each IHA. For beluga whales, the
amount of take proposed represents slightly under eight percent of the
population for each IHA.
Table 15--Percent of Stock Proposed To Be Taken by Level B Harassment Under Each IHA
----------------------------------------------------------------------------------------------------------------
Abundance Proposed take Percent of
Species Stock (Nbest) (Level B) stock
----------------------------------------------------------------------------------------------------------------
Year 1:
Humpback whale.................... Western North Pacific... 11,571 6 0.05
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 10 1.7
Alaska, Aleutian 2,347 0.43
Islands, and Bering Sea
Transient.
Beluga whale...................... Cook Inlet.............. 279 22 7.89
[[Page 27623]]
Dall's porpoise................... Alaska.................. 83,400 6 0.01
Harbor porpoise................... Gulf of Alaska.......... 31,046 44 0.14
Harbor seal....................... Cook Inlet/Shelikof..... 26,907 554 2.06
Steller sea lion.................. Western................. 53,624 17 0.03
California sea lion............... U.S..................... 233,515 5 0.00
Year 2:
Humpback whale.................... Western North Pacific... 11,571 6 0.05
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 10 1.7
Alaska, Aleutian 0.43
Islands, and Bering Sea
Transient.
Beluga whale...................... Cook Inlet.............. 279 22 7.89
Dall's porpoise................... Alaska.................. 83,400 6 0.01
Harbor porpoise................... Gulf of Alaska.......... 31,046 44 0.14
Harbor seal....................... Cook Inlet/Shelikof..... 26,907 554 2.06
Steller sea lion.................. Western................. 53,624 17 0.03
California sea lion............... U.S..................... 233,515 2 0.00
----------------------------------------------------------------------------------------------------------------
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals will be taken relative to the population size
of the affected species or stocks for the Year 1 IHA. Separately, NMFS
also preliminarily finds that small numbers of marine mammals will be
taken relative to the population size of the affected species or stocks
for the Year 2 IHA.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity will not have an unmitigable adverse impact on the
availability of such species or stock for taking for subsistence uses
by Alaska Natives. NMFS has defined ``unmitigable adverse impact'' in
50 CFR 216.103 as an impact resulting from the specified activity: (1)
That is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) Placing physical barriers
between the marine mammals and the subsistence hunters; and (2) That
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
To further minimize any potential effects of their action on
subsistence activities, Hilcorp has outlined their communication plan
for engaging with subsistence users in their Stakeholder Engagement
Plan (Appendix B of Hilcorp's application). Hilcorp will be required to
abide by this plan and update the plan accordingly.
Subsistence communities identified as project stakeholders near
Hilcorp's middle Cook Inlet and Trading Bay activities include the
Village of Salamatof and the Native Village of Tyonek. The ADF&G
Community Subsistence Information System does not contain data for
Salamatof. For the purposes of our analyses for the Year 1 and Year 2
IHAs, we can assume the subsistence uses are similar to those of nearby
communities such as Kenai. At 3.5 km away from the closest point of
approach, Tyonek is the closest subsistence community to Hilcorp's
proposed tug route. Tyonek, on the western side of lower Cook Inlet,
has a subsistence harvest area that extends from the Susitna River
south to Tuxedni Bay (BOEM 2016). In Tyonek, harbor seals were
harvested between June and September by 6 percent of the households
(Jones et al. 2015). Seals were harvested in several areas,
encompassing an area stretching 32.2 km (20 miles) along the Cook Inlet
coastline from the McArthur Flats north to the Beluga River. Seals were
searched for or harvested in the Trading Bay areas as well as from the
beach adjacent to Tyonek (Jones et al. 2015).
Subsistence hunting of whales is not known to currently occur in
Cook Inlet. Hilcorp's tug towing jack-up rig activities may overlap
with subsistence hunting of seals. However, these activities typically
occur along the shoreline or very close to shore near river mouths,
whereas most of Hilcorp's tugging is in the middle of the Inlet and
rarely near the shoreline or river mouths. Any harassment to harbor
seals is anticipated to be short-term, mild, and not result in any
abandonment or behaviors that would make the animals unavailable to
Alaska Natives.
Based on the description of the specified activity, the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there will
not be an unmitigable adverse impact on subsistence uses from
Hilcorp's's proposed activities under the Year 1 IHA. Separately, NMFS
has also preliminarily determined that there will not be an unmitigable
adverse impact on subsistence uses from Hilcorp's proposed activities
under the Year 2 IHA.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA; 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species, in this case with the Alaska Regional
Protected Resources Division Office.
NMFS is proposing to authorize take of humpback whales (Mexico DPS,
Western North Pacific DPS), fin whales (Northeastern Pacific stock),
beluga whales (Cook Inlet stock), and Steller
[[Page 27624]]
sea lion (Western DPS), which are listed under the ESA.
The Permit and Conservation Division has requested initiation of
Section 7 consultation with the NMFS Alaska Region for the issuance of
these two IHAs. NMFS will conclude the ESA consultation prior to
reaching a determination regarding the proposed issuance of the
authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue two consecutive IHAs to Hilcorp for its tugs towing a jack-up rig
in Cook Inlet in 2022-2023 and 2023-2024 open water seasons, provided
the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. Drafts of the proposed IHAs can be found
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>.
Request for Public Comments
We request comment on our analyses, the proposed authorizations,
and any other aspect of this notice of proposed IHAs for the proposed
tug towing jack-up rig activity. We also request at this time comment
on the potential renewal of this proposed IHA as described in the
paragraph below. Please include with your comments any supporting data
or literature citations to help inform decisions on the request for
this IHA or a subsequent Renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, one-year
Renewal IHA following notice to the public providing an additional 15
days for public comments when (1) up to another year of identical or
nearly identical activities as described in the Description of Proposed
Activities section of this notice is planned or (2) the activities as
described in the Description of Proposed Activities section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed Renewal IHA effective date (recognizing that the
Renewal IHA expiration date cannot extend beyond one year from
expiration of the initial IHA).
<bullet> The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested Renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: May 4, 2022.
Kimberly Damon-Randall,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2022-09916 Filed 5-6-22; 8:45 am]
BILLING CODE 3510-22-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.