Billing Code 3510-22-P
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XD682]
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine
Mammals Incidental to Furie Operating Alaska, LLC Oil and Gas Activities 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 and possible renewals.
SUMMARY: NMFS has received a request from Furie Operating Alaska, LLC (Furie)
for authorization to take marine mammals incidental to oil and gas activities in Cook
Inlet, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to issue two consecutive incidental harassment
authorizations (IHAs) to incidentally take marine mammals during the specified
activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that
could be issued for either or both of the two IHAs 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 [INSERT DATE 30
DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, Permits and
Conservation Division, Office of Protected Resources, National Marine Fisheries Service

and should be submitted via email to ITP.Davis@noaa.gov. Electronic copies of the
application and supporting documents, as well as a list of the references cited in this
document, may be obtained online at: https://www.fisheries.noaa.gov/national/marinemammal-protection/incidental-take-authorizations-oil-and-gas. In case of problems
accessing these documents, please call the contact listed below.
Instructions: NMFS is not responsible for comments sent by any other method, to
any other address or individual, or received after the end of the comment period.
Comments, including all attachments, must not exceed a 25-megabyte file size. All
comments received are a part of the public record and will generally be posted online at
https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-takeauthorizations-oil-and-gas 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: Leah Davis, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the “take” of marine mammals, with certain exceptions.
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary
of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not
intentional, taking of small numbers of marine mammals by U.S. citizens who engage in
a specified activity (other than commercial fishing) within a specified geographical
region if certain findings are made and either regulations are proposed or, if the taking is
limited to harassment, a notice of a proposed IHA is provided to the public for review.

Authorization for incidental takings shall be granted if NMFS finds that the taking
will have a negligible impact on the species or stock(s) and will not have an unmitigable
adverse impact on the availability of the species or stock(s) for taking for subsistence
uses (where relevant). Further, NMFS must prescribe the permissible methods of taking
and other “means of effecting the least practicable adverse impact” on the affected
species or stocks and their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance, and on the availability of the species or stocks
for taking for certain subsistence uses (referred to in shorthand as “mitigation”); and
requirements pertaining to the mitigation, monitoring and reporting of the takings are set
forth. The definitions of all applicable MMPA statutory terms cited above are included in
the relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA; 42
U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, NMFS must
review our proposed action (i.e., the issuance of an IHA) with respect to potential impacts
on the human environment. Accordingly, NMFS is preparing an Environmental
Assessment (EA) to consider the environmental impacts associated with the issuance of
the proposed IHA. NMFS’ EA will be made available at
https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-takeauthorizations-oil-and-gas 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 request.
Summary of Request
On July 19, 2023, NMFS received a request from Furie for two consecutive IHAs
to take marine mammals incidental to oil and gas activities in Cook Inlet, Alaska. The
application was deemed adequate and complete on April 5, 2024. Furie’s request is for

take of 12 species of marine mammals, by Level B harassment and, for harbor seals,
Level A harassment. Neither Furie nor NMFS expect serious injury or mortality to result
from this activity and, therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
From April 1, 2024, through March 31, 2025 (Year 1), and from April 1, 2025
through March 31, 2026 (Year 2), Furie is planning to conduct the following oil and gas
activities in Middle Cook Inlet, Alaska. In Year 1, Furie proposes to relocate the
Enterprise 151 jack-up production rig (Enterprise 151 or rig) to the Julius R. Platform
(JRP) site, install up to two conductor piles using an impact hammer, and conduct
production drilling of up to two natural gas wells at the JRP with the Enterprise 151 rig
(or a similar rig) across 45-180 days. During Year 2, Furie proposes to relocate the
Enterprise 151 rig to the JRP site again, potentially install one to two conductor piles
using an impact hammer (depending on whether either or both of these piles are installed
or not during Year 1), and conduct additional production drilling at the JRP. Furie
proposes to conduct the rig towing and pile driving activities between April 1 and
November 15 each year, but if favorable ice conditions occur outside of that period, it
may tow the rig or pile drive outside of that period. Noise produced by rig towing and
installation of the conductor piles may result in take, by Level B harassment, of marine
mammals, and for harbor seals, also Level A harassment. Thus references to tugging
activities herein refer to activities where tugs are under load with the rig.
Dates and Duration
NMFS anticipates that the proposed Year 1 IHA would be effective for 1 year
beginning mid-to-late 2024, and the proposed Year 2 IHA would be effective for one
year beginning mid-to-late 2025. The final effective dates would be determined based
upon when Furie anticipates being able to secure the rig from another operator in Cook

Inlet. As noted above, Furie expects to conduct the rig towing and pile driving activities
between April 1 and November 15 each year, but if favorable ice conditions occur
outside of that period, it may tow the rig or pile drive outside of that period. Furie will
conduct impact installation of conductor piles during daylight hours only, and it will only
conduct rig towing at night if necessary to accommodate a favorable tide. Production
drilling may be conducted 24 hours per day.
Specific Geographic Region
Furie’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; and upper Cook
Inlet refers to waters north and east of Beluga River on the west and Point Possession on
the east. The JRP is located in middle Cook Inlet, approximately 8 miles due south of
Tyonek, Alaska, and approximately 10 miles offshore from the shoreline to the southeast
of the JRP.
The southernmost area of operation during Furie’s Year 1 and Year 2 drilling
projects is the Rig Tenders Dock, located in Nikiski, Alaska, where the Enterprise 151 rig
overwinters. The Rig Tenders Dock is in lower Cook Inlet, approximately 2.3 miles south
of the East Foreland. The northernmost location at which Furie may assume operatorship
of the Enterprise 151 rig is Hilcorp Alaska LLC’s (Hilcorp) Bruce platform, located 6.4
miles (10.3 kilometers (km)) northwest of the JRP. Hilcorp has stated that they do not
intend to conduct work at the Tyonek platform in 2024 or 2025, and therefore, Furie does
not intend to operate or tow the Enterprise 151 north of the Bruce platform. The Tyonek
platform is within the Susitna Delta Exclusion Zone identified in Hilcorp’s IHAs (87 FR
62364, October 14, 2022). If Hilcorp does conduct work at the Tyonek platform, it would
maintain operatorship and control of the Enterprise 151 until the tow is underway with

lines taut and the Enterprise 151 is under tug power. As a result, Hilcorp would maintain
responsibility for any applicable mitigation measures in their current IHA that must be
met before a tow may be initiated. Once the tow is underway, Furie representatives would
take over operatorship of the Enterprise 151.
Furie expects to tow the Enterprise 151 once or twice each season. The origin of
the first rig tow before Furie’s use at the JRP and the destination of the tow after use at
the JRP is yet to be determined, as Hilcorp also intends to use the Enterprise 151 for
similar work in the same region of Cook Inlet, so Furie and Hilcorp must coordinate the
use of the Enterprise 151. Furie may assume operatorship of the Enterprise 151 from
Hilcorp mid-season, pass operatorship to Hilcorp mid-season, or be the sole operator of
the rig if Hilcorp does not use it.
If Furie is the first to operate the Enterprise 151 in a season, the origination of the
first tow is likely to begin at the Rig Tenders Dock and would end at the JRP. If Furie is
the sole operator of the Enterprise 151 within a season, the rig would be returned to Rig
Tenders at the end of the production drilling operation. However, if Hilcorp is the first to
use the Enterprise 151 rig, the origination of Furie’s tow could be any of Hilcorp’s assets
(i.e., platforms or well locations within the lease areas operated by Hilcorp). If Hilcorp
uses the Enterprise 151 after Furie, operatorship and responsibility for the rig tow will
pass to Hilcorp when it is towed from JRP to one of its Cook Inlet assets.
A map of the specific area in which Furie plans to operate is provided in figure 1.

Figure 1-- Furie's Proposed Activity Location
Detailed Description of the Specified Activity
Year 1
Tug Towing and Positioning- Furie proposes to conduct production drilling at the
JRP with the Enterprise 151 rig (or a similar rig; see Furie’s IHA application for
additional information about the Enterprise 151 rig). A jack-up rig is not self-propelled
and requires vessels (tugs or heavy-lift ships) to transport it to an offshore drilling
location. The Enterprise 151 has a buoyant triangular hull, allowing it to be towed like a

barge. The rig will be towed to the JRP by up to three ocean-going tugboats. (Table 2
describes potential rig tow origins and destinations.) Upon arrival at the JRP, a fourth
tugboat may join the other three for up to 1 hour to complete the precise positioning of
the rig next to the JRP. The tugboats are expected to be rated between 4,000 horsepower
(hp) and 8,000 hp. Specifications of the proposed tugs are provided in table 1.
Table 1-- Tugboat Specifications
Vessel
M/V Bering
Wind
M/V Anna T

Activity
Towing and positioning
the jack-up rig
Towing and positioning
the jack-up rig
M/V Bob Franco Towing and positioning
the jack-up rig
M/V TBD
Positioning the jack-up
rig
Note: m= meters, ft= feet

Length
22 m
(72 ft)
32 m
(105 ft)
37 meters
(121 ft)
Unknown

Width
10 m
(33 ft)
11 m
(36 ft)
11 meters
(36 ft)
Unknown

Gross Tonnage
144
160
196
Unknown

Several factors will determine the duration that the tugboats are towing the
Enterprise 151, including the origin and destination of the towing route (e.g., Rig Tenders
Dock, the JRP, one of Hilcorp’s platforms) and the tidal conditions. For safety reasons, a
high slack tide is required to access the shallow water near the dock at Rig Tenders Dock,
whether beginning a tow or returning the Enterprise 151. In all other locations, a slack
tide at either high or low tide is required to attach the tugs to the rig and float it off
position or to position the rig and detach from it. Potential tug power output for these
scenarios is discussed in further detail in the Estimated Take of Marine Mammals
section.
The specific towing origin and destination of the Enterprise 151 depends on
whether Hilcorp contracts to use the Enterprise 151 before or after Furie in the same
season. For example, Furie may assume operatorship of the Enterprise 151 at the
beginning of the season from the Rig tenders dock, or it may assume operatorship midseason at one of Hilcorp’s platforms or drilling locations (rather than at the Rig Tenders
Dock), and tow the rig to the JRP. However, Hilcorp may assume operatorship and begin

towing the rig from the JRP to one of their platforms or drilling locations. As a result,
Furie may tow the rig once or twice within the season, beginning at several potential
locations. However, if Furie operates the Enterprise 151 last, or is the only operator, the
second tow of the season would return the Enterprise 151 to the Rig Tenders Dock. Table
2 displays the potential scenarios.
Table 2-- Potential Rig Tow Origins and Destinations
Scenario
Furie is Sole Operator
Furie Early Season, Hilcorp Late
Season
Hilcorp Early Season, Furie Late
Season1

Tow #1
Furie tows from the Rig Tenders
Dock to the JRP
Furie tows from the Rig Tenders
Dock to the JRP
Furie tows from a Hilcorp-operated
platform or drill site to the JRP

Tow #2
Furie tows from the JRP to the Rig
Tenders Dock
Hilcorp tows from the JRP to a
Hilcorp-operated platform or drill site
Furie tows from the JRP to the Rig
Tenders Dock

One potential variation to this scenario may result if Hilcorp operates the Enterprise 151 early season
and conducts work at the Tyonek platform or elsewhere within the North Cook Inlet Unit. The Tyonek
platform is within the Susitna Delta Exclusion Zone identified in Hilcorp’s IHAs (87 FR 62364, October
14, 2022). If Hilcorp does conduct work at the Tyonek platform, it would maintain operatorship and
control of the Enterprise 151 until the tow is underway with lines taut and the Enterprise 151 is under tug
power. As a result, Hilcorp would maintain responsibility for any applicable mitigation measures in their
existing IHA that must be met before a tow may be initiated. Once the tow is underway, Furie
representatives will take over operatorship of the Enterprise 151.
A tow starting at the Rig Tenders Dock would begin at high slack tide, pause near
the Offshore Systems Kenai (OSK) Dock to wait for currents to slow (up to three hours),
then arrive at the JRP at the next high slack tide (approximately 12 hours after departure).
Once the tugs arrive at the JRP, there is a 1- to 2-hour window when the slack tide
current velocity is slow (1 to 2 knots), allowing the tugs to position the Enterprise 151 rig
and pin the legs to the bottom. Upon return, the tugs would be secured to the Enterprise
151 at the JRP on a high slack tide, float off location, and transit south with the outgoing
tide south towards Nikiski, Alaska. The tow will likely pause near OSK to wait for the
tide cycle to return to a high flood before moving near the Rig Tenders Dock to bring it
close to shore on high slack. Therefore, the tugs will be under load, typically at halfpower or less, for up to 14 hours during mobilization to the JRP from Rig Tenders or
demobilization in reverse order.

If the rig tow begins at a Hilcorp platform or drill site (excluding the northern
locations), then the Enterprise 151 may be lowered, secured to the tugs, and floated off
location during low slack to take advantage of the flood tide to tow the rig north or east to
the JRP. In this scenario, the total tow duration is expected to be approximately 8 hours,
allowing for the 6 hours between the low slack and high slack and an additional 1 to 2
hours to position the rig.
The tugs may abort the first positioning attempt until favorable conditions return
if it takes longer than anticipated and the current velocity exceeds 3 to 4 knots. If so, the
tugs will move the rig nearby, where the legs can be temporarily lowered to the seafloor
to secure it. The tugs will remain close by, jogging in the current until the positioning
attempt can be resumed. The tugs usually complete the positioning on the first attempt,
but they may be under power for approximately five additional hours if a second attempt
is needed.
The tugs will generally attempt to transport the rig by traveling with the tide,
except when circumstances threaten human safety, property, or infrastructure. The rig
may need to be towed against the tide to a safe harbor if a slack tide window is missed or
extreme weather events occur.
Conductor Pipe Installation- Active wells occupy four of the six well slots within
the caisson (monopod leg) of the JRP. During Year 1, Furie intends to drill up to two
natural gas wells, either “grassroots” or “sidetrack” wells. A grassroots well requires
drilling a new wellbore from the surface to the gas-bearing formations, and requires all
new components from the surface to the bottom depth, including a conductor pipe,
surface and subsurface casing, cement, production liner, tubulars, chokes, sleeves, and a
wellhead. A sidetrack well is a new branch drilled from within an existing well. A
sidetrack well requires fewer new components because many existing components, such
as the conductor pipe, surface casing, and wellhead, are re-used.

The conductor pipe is the uppermost portion of a gas well and supports the initial
sedimentary part of the well, preventing the surface layers from collapsing and
obstructing the wellbore. The pipe also facilitates the return of cuttings from the drill
head and supports the wellhead components.
Furie expects to install a 20-inch conductor pipe in each of the two empty well
slots in Year 1 but expects to complete only one grassroots well and one sidetrack well in
Year 1. Furie would install the conductor pipe with an impact hammer Delmag D62
impact hammer (see Furie’s IHA application for additional hammer details). As the pipe
is driven into the sediment, the sections are connected either by welding or drivable quick
connections. Once installed, the conductor pipes remain a permanent component of the
natural gas wells. Installation of each conductor pile is anticipated to take approximately
2 days, with 70 percent of the installation occurring on day 1, and the remaining 30
percent of the installation occurring on day 2. Furie will conduct the pile driving during
daylight hours only.
Drilling Operations- Furie proposes to conduct production drilling activities after
the conductor pipe installation is complete and the Enterprise 151 is positioned at the
JRP. Furie expects to drill up to two wells each year, which could be any combination of
new grassroots wells or sidetrack wells, to maintain or increase natural gas production
levels to meet critical local energy needs.
After the Enterprise 151 is positioned next to the JRP, the rig will jack up so that
the hull is initially approximately 5 to 10 ft out of the water. To set the spud cans on the
bottoms of the legs securely into the seafloor and ensure stability, the Enterprise 151 has
specialized “preload” tanks within the hull that are filled with seawater and designed to
add weight to the hull. The preload is conducted while the hull is only slightly out of the
water to maintain a lower center of gravity until full settling and stability are achieved.

After preloading, the seawater is discharged, and the hull is raised so that the drilling
derrick can be cantilevered over the top deck of the JRP and positioned over a well slot.
Offshore support vessels (OSVs) support all operating offshore platforms in Cook
Inlet throughout the open water season and will be used during Furie’s planned drilling
operations to transport equipment and supplies between the OSK Dock and the Enterprise
151. During production drilling, an average of two daily vessel trips are expected
between the OSK Dock and the rig. No take of marine mammals is anticipated from the
operation of OSVs, and OSVs are not discussed further in this application beyond the
explanation provided here. Because vessels will be in transit, exposure to vessel noise
will be temporary, relatively brief and will occur in a predictable manner, and also the
sounds are of relatively lower levels. Elevated background noise from multiple vessels
and other sources can interfere with the detection or interpretation of acoustic cues, but
the brief exposures to OSVs would be unlikely to disrupt behavioral patterns in a manner
that would qualify as take.
Helicopters will transport personnel and supplies from shore to the rig and
platform during production drilling activities. Helicopters would be required to follow the
mitigation measures described in the Proposed Mitigation section of this notice (e.g.,
helicopters must maintain an altitude of 1,500 ft (457 m)), and therefore, take from
helicopter activity is not anticipated, and helicopter activity is not discussed further aside
from the mitigation discussion in the Proposed Mitigation section.
Other potential sources of sound from the Enterprise 151 include the operation of
the diesel generators, mud and cement pumps, and ventilation fans. In 2016, while the
Randolph Yost jack-up rig was drilling at the JRP, Denes and Austin (2016)
characterized drilling and mud pumping sound as 158 decibels (dB) root mean square
(rms) at 1 m and 148.8 dB rms at 1 m, respectively. In 2011, while the Enterprise 151
was conducting exploration drilling in Furie’s Kitchen Lights Unit lease area, Marine

Acoustics Inc. (2011) performed a sound source verification (SSV) near the JRP in water
depths ranging from 24.4 to 27.4 m (80 to 90 ft). The SSV measured sound from the
diesel generator engines at 137 dB re 1 μPa rms at 1 meter within the frequency
bandwidth of 141 to 178 hertz (Hz). The SSV also identified the PZ-10 mud pump and
ventilation fans as minor sources of underwater sound. Based on the 137 dB re 1
microPascal (μPa) rms measured at 1 m, the Level B harassment isopleth was estimated
to be 50 m from the jack-up leg or drill riser. As such, drilling, mud pumping, and
generator noise are not anticipated to result in take of marine mammals, and these
activities are not discussed further.
Year 2
In Year 2, Furie would use the same tugboat arrangement to tow the Enterprise
151 to and from the JRP and position it, as described above for Year 1. Furie proposes to
drill up to two wells in Year 2 that could be either new grassroots wells, sidetracks, or a
combination of each. Furie intends to conduct additional production drilling in Year 2 at
the JRP with the Enterprise 151 rig (or a similar rig). Furie expects to install both
conductor pipes at the JRP in Year 1, but one or both may be installed in Year 2 instead
(though no more than two will be installed over the course of both seasons because only
two well slots remain to accept new conductors).
Proposed mitigation, monitoring, and reporting measures are described in detail
later in this document (please see Proposed Mitigation and Proposed Monitoring and
Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information regarding
status and trends, distribution and habitat preferences, and behavior and life history of the
potentially affected species. NMFS fully considered all of this information, and we refer
the reader to these descriptions, instead of reprinting the information. Additional

information regarding population trends and threats may be found in NMFS’ Stock
Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammalprotection/marine-mammal-stock-assessments) and more general information about these
species (e.g., physical and behavioral descriptions) may be found on NMFS’ website
(https://www.fisheries.noaa.gov/find-species).
Table 3 lists all species or stocks for which take is expected and proposed to be
authorized for this activity and summarizes information related to the population or stock,
including regulatory status under the MMPA and Endangered Species Act (ESA) and
potential biological removal (PBR), where known. PBR is defined by the MMPA as the
maximum number of animals, not including natural mortalities, that may be removed
from a marine mammal stock while allowing that stock to reach or maintain its optimum
sustainable population (as described in NMFS’ SARs). While no serious injury or
mortality is anticipated or proposed to be authorized here, PBR and annual serious injury
and mortality from anthropogenic sources are included here as gross indicators of the
status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document represent the
total number of individuals that make up a given stock or the total number estimated
within a particular study or survey area. NMFS’ stock abundance estimates for most
species represent the total estimate of individuals within the geographic area, if known,
that comprises that stock. For some species, this geographic area may extend beyond U.S.
waters. All managed stocks in this region are assessed in NMFS’ U.S. 2022 SARs. All
values presented in table 3 are the most recent available at the time of publication
(including from the draft 2023 SARs) and are available online at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammalstock-assessments.

Table 3 -- Species1 Likely Impacted by the Specified Activities

ESA/MMPA
status;
Common
Strategic
name
Scientific name Stock
(Y/N)2
Order Artiodactyla – Cetacea – Mysticeti (baleen whales)
Family Eschrichtiidae
Eschrichtius
Eastern N
Gray Whale
robustus
Pacific
-, -, N
Family Balaenidae
Family Balaenopteridae (rorquals)
Balaenoptera
Northeast
Fin Whale
physalus
Pacific
E, D, Y
Humpback
Megaptera
Whale
novaeangliae
Hawai'i
-, -, N
Humpback
Megaptera
MexicoWhale
novaeangliae
North Pacific T, D, Y
Humpback
Whale

Megaptera
Western
novaeangliae
North Pacific E, D, Y
Balaenoptera
Minke Whale
acutorostrata
AK
-, -, N
Odontoceti (toothed whales, dolphins, and porpoises)
Family Delphinidae
Eastern
North Pacific
Alaska
Killer Whale
Orcinus orca
Resident
-, -, N
Eastern
North Pacific
Gulf of
Alaska,
Aleutian
Islands and
Bering Sea
Killer Whale
Orcinus orca
Transient
-, -, N
Pacific White- Lagenorhynchu
Sided Dolphin s obliquidens
N Pacific
-, -, N
Family Monodontidae (white whales)
Delphinapterus
Beluga Whale leucas
Cook Inlet
E, D, Y
Family Phocoenidae (porpoises)
Dall's
Phocoenoides
Porpoise
dalli
AK
Harbor
Phocoena
Gulf of
Porpoise
phocoena
Alaska
Order Carnivora – Pinnipedia
Family Otariidae (eared seals and sea lions)

CA Sea Lion

Zalophus
californianus

Steller Sea
Eumetopias
Lion
jubatus
Family Phocidae (earless seals)

-, -, N
-, -, Y

U.S.

-, -, N

Western

E, D, Y

Stock
abundance
(CV, Nmin,
most recent
abundance
survey)3

PBR

Annua
l
M/SI4

26,960 (0.05,
25,849, 2016)

131

UND

0.6

27.09

UND

0.57

3.4

5.82

UND

19

1.3

5.9

0.8

UND

0.53

UND10
(UND, UND,
2015)
31,046 (0.21,
N/A, 1998)

UND

UND

257,606
(N/A,
233,515,
2014)
49,837 11
(N/A, 49,837,
2022)

14,011

>321

267

UND5 (UND,
UND, 2013)
11,278 (0.56,
7,265, 2020)
N/A6 (N/A,
N/A, 2006)
1,0847
(0.088, 1,007,
2006)
N/A8 (N/A,
N/A, N/A)

1,920 (N/A,
1,920, 2019)

587 (N/A,
587, 2012)
26,880 (N/A,
N/A, 1990)
2799 (0.061,
267, 2018)

Cook
Inlet/Sheliko
28,411 (N/A,
Harbor Seal
Phoca vitulina
f Strait
-, -, N
26,907, 2018) 807
107
1 - Information on the classification of marine mammal species can be found on the web page for The
Society for Marine Mammalogy's Committee on Taxonomy (https://marinemammalscience.org/scienceand-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)).
2 - ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the
species is not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a
strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is
determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species
or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic
stock.
3- NMFS marine mammal SARs online at: https://www.fisheries.noaa.gov/national/marine-mammalprotection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the
minimum estimate of stock abundance.
4 - These values, found in NMFS’s SARs, represent annual levels of human-caused mortality plus serious
injury from all sources combined (e.g., commercial fisheries, ship strike). Annual M/SI often cannot be
determined precisely and is in some cases presented as a minimum value or range. A CV associated with
estimated mortality due to commercial fisheries is presented in some cases.
5 - The best available abundance estimate for this stock is not considered representative of the entire stock
as surveys were limited to a small portion of the stock's range. Based upon this estimate and the Nmin, the
PBR value is likely negatively biased for the entire stock.
6 - Abundance estimates are based upon data collected more than 8 years ago and, therefore, current
estimates are considered unknown.
7- The best estimates of abundance for the stock (1,084) and the portion of the stock migrating to
summering areas in U.S. waters (127) were derived from a reanalysis of the 2004-2006 SPLASH data
(Wade 2021). Although these data are more than fifteen years old, the estimates are still considered valid
minimum population estimates.
8- Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini
et al. (2006) for additional information on numbers of minke whales in Alaska.
9- On June 15, 2023, NMFS released an updated abundance estimate for endangered Cook Inlet beluga
whales in Alaska (Goetz et al. 2023). Data collected during NOAA Fisheries’ 2022 aerial survey suggest
that the whale population is stable or may be increasing slightly. Scientists estimated that the population
size is between 290 and 386, with a median best estimate of 331. In accordance with the MMPA, this
population estimate will be incorporated into the Cook Inlet beluga whale SAR, which will be reviewed by
an independent panel of experts, the Alaska Scientific Review Group. After this review, the SAR will be
made available as a draft for public review before being finalized.
10 - The best available abundance estimate is likely an underestimate for the entire stock because it is based
upon a survey that covered only a small portion of the stock's range.
11 - Nest is best estimate of counts, which have not been corrected for animals at sea during abundance
surveys.

As indicated above, all 12 species (with 14 number managed stocks) in table 3
temporally and spatially co-occur with the activity to the degree that take is reasonably
likely to occur. In addition, the northern sea otter may be found in Cook Inlet, Alaska.
However, northern sea otters are managed by the U.S. Fish and Wildlife Service and are
not considered further in this document.
Gray Whale
The stock structure for gray whales in the Pacific has been studied for a number
of years and remains uncertain as of the most recent (2022) Pacific SARs (Carretta et al.

2023). Gray whale population structure is not determined by simple geography and may
be in flux due to evolving migratory dynamics (Carretta et al. 2023). Currently, the SARs
delineate a western North Pacific (WNP) gray whale stock and an eastern North Pacific
(ENP) stock based on genetic differentiation (Carretta et al. 2023). WNP gray whales are
not known to feed in or travel to upper Cook Inlet (Conant and Lohe, 2023; Weller et al.
2023). Therefore, we assume that gray whales near the project area are members of the
ENP stock.
An Unusual Mortality Event (UME) for gray whales along the West Coast and in
Alaska occurred from December 17, 2018 through November 9, 2023. During that time,
146 gray whales stranded off the coast of Alaska. The investigative team concluded that
the preliminary cause of the UME was localized ecosystem changes in the whale’s
Subarctic and Arctic feeding areas that led to changes in food, malnutrition, decreased
birth rates, and increased mortality (see https://www.fisheries.noaa.gov/national/marinelife-distress/2019-2023-gray-whale-unusual-mortality-event-along-west-coast-and for
more information).
Gray whales occur infrequently in Cook Inlet, but can occur seasonally during
spring and fall in the lower inlet (Bureau of Ocean Energy Management (BOEM) 2021).
Migrating gray whales pass through the lower inlet during their spring and fall migrations
to and from their primary summer feeding areas in the Bering, Chukchi, and Beaufort
seas (Swartz 2018; Silber et al. 2021; BOEM 2021).
Some gray whales remain in certain coastal areas in the Pacific Northwest,
including lower Cook Inlet, instead of migrating to the Arctic in summer (Moore et al.
2007). Several surveys and monitoring programs have sighted gray whales in lower Cook
Inlet (Shelden et al. 2013; Owl Ridge 2014; Lomac-MacNair et al. 2013, 2014; Kendall
et al. 2015, as cited in Weston and SLR 2022). Gray whales are occasionally seen in midand upper Cook Inlet, Alaska, but they are not common. In 2020, a young male gray

whale was stranded in the Twentymile River near Girdwood for over a week before
swimming back into Turnagain Arm. The whale did not survive and was found dead in
west Cook Inlet later that month (NOAA Fisheries 2020). One gray whale was sighted in
Knik Arm near the POA in upper Cook Inlet in May of 2020 during observations
conducted during construction of the Petroleum and Cement Terminal project (61N
2021). The sighting occurred less than a week before the reports of the gray whale
stranding in the Twentymile River and was likely the same animal. In 2021, one small
gray whale was sighted in Knik Arm near Ship Creek, south of the POA (61N 2022a).
Although some sightings have been documented in the middle and upper Inlet, the gray
whale range typically only extends into the lower Cook Inlet region.
Humpback Whale
Humpback whales have been observed during marine mammal surveys conducted
in Cook Inlet, with the majority sighted in lower Cook Inlet south of Kalgin Island.
Eighty-three groups containing an estimated 187 humpbacks were sighted during the
Cook Inlet beluga whale aerial surveys conducted by NMFS from 1994 to 2012 (Shelden
et al. 2013). Surveys conducted north of the forelands have documented small numbers in
middle Cook Inlet. Vessel-based observers participating in the Apache Corporation’s
2014 survey operations recorded three humpback whale sightings near Moose Point in
upper Cook Inlet and two sightings near Anchor Point, while aerial and land-based
observers recorded no humpback whale sightings, including in the upper Inlet (LomacMacNair et al. 2014). In 2015, during the construction of Furie’s platform and pipeline,
four groups of humpback whales were documented. Another group of 6 to 10
unidentified whales, thought to be either humpback or gray whales, was sighted
approximately 15 km northeast of the JRP. Large cetaceans were visible near the project
(i.e., whales or blows were visible), for 2 hours out of the 1,275 hours of observation
conducted (Jacobs 2015). During SAExploration’s 2015 seismic program, three

humpback whales were observed in Cook Inlet, including two near the Forelands and one
in lower Cook Inlet (Kendall et al. 2015 as cited in Weston and SLR 2022). Hilcorp did
not record any sightings of humpback whales from their aerial or rig-based monitoring
efforts in 2023 (Horsley and Larson 2023).
The most comprehensive photo-identification data available suggest that
approximately 89 percent of all humpback whales in the Gulf of Alaska are from the
Hawaii stock, 11 percent are from the Mexico stock, and less than 1 percent are from the
WNP stock (Wade, 2021). Individuals from different stocks are known to intermix in
feeding grounds. There is no designated critical habitat for humpback whales in or near
the Project area (86 FR 21082, April 21, 2021), nor does the project overlap with any
known biologically important areas (BIAs).
Minke Whale
Minke whales are most abundant in the Gulf of Alaska during summer and
occupy localized feeding areas (Zerbini et al. 2006). During the NMFS annual and
semiannual surveys of Cook Inlet, minke whales were observed near Anchor Point in
1998, 1999, 2006, and 2021 (Shelden et al. 2013, 2015, 2017, 2022; Shelden and Wade
2019) and near Ninilchik and the middle of lower Cook Inlet in 2021 (Shelden et al.
2022). Minkes were sighted southeast of Kalgin Island and near Homer during Apache’s
2014 survey (Lomac-MacNair et al. 2014), and one was observed near Tuxedni Bay in
2015 (Kendall et al. 2015, as cited in Weston and SLR 2022). During Hilcorp’s seismic
survey in lower Cook Inlet in the fall of 2019, eight minke whales were observed
(Fairweather Science 2020). In 2018, no minke whales were observed during
observations conducted for the Cross Inlet Pipeline (CIPL) project near Tyonek
(Sitkiewicz et al. 2018). Minke whales were also not recorded during Hilcorp’s aerial or
rig-based monitoring efforts in 2023 (Horsley and Larson 2023).
Fin Whale

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 Cook Inlet have only
been observed as individuals or in small groups. Sightings of fin whales in Cook Inlet are
rare; most occur near the entrance. From 2000 to 2022, 10 sightings of 26 estimated
individual fin whales in lower Cook Inlet were observed during NMFS aerial surveys
(Shelden et al. 2013, 2015, 2017, 2022; Shelden and Wade 2019). None were observed in
the area of Furie’s proposed drilling project. In the fall of 2019, during Hilcorp’s seismic
survey in lower Cook Inlet, eight sightings of 23 fin whales were documented, suggesting
greater numbers may use the area in the fall than previously estimated (Fairweather
Science 2020). Hilcorp did not record any sightings of fin whales from their aerial or rigbased monitoring efforts in 2023 (Horsley and Larson 2023)
Beluga Whale
NMFS designated Cook Inlet beluga whales as depleted under the MMPA in 2000
and listed the population as endangered under the ESA in 2008 (73 FR 62919, October
10, 2008) when it 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). Between 2008 and 2018, Cook Inlet belugas
experienced a decline of about 2.3 percent per year (Wade et al. 2019). The decline
overlaps with the northeast Pacific marine heatwave that occurred from 2014 to 2016 in
the Gulf of Alaska, significantly impacting the marine ecosystem (Suryan et al. 2020, as
cited in Goetz et al. 2023). The most recent abundance estimate calculated an average
annual increase between 0.2 and 0.9 percent between 2012 and 2022 (Goetz et al. 2023).

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 2016). Another source of Cook Inlet beluga whale mortality in Cook Inlet is
predation by transient-type (mammal-eating) killer whales (NMFS 2016b; Shelden et al.
2003). No human-caused mortality or serious injury of Cook Inlet beluga whales through
interactions with commercial, recreational, and subsistence fisheries, takes by subsistence
hunters, and or human-caused events (e.g., entanglement in marine debris, ship strikes)
has been recently documented and harvesting of Cook Inlet beluga whales has not
occurred since 2008 (NMFS 2008b).
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. (HeideJoregensen 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 2 to 3 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 (kilohertz) 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). The ecological range of Cook Inlet belugas has contracted
significantly since the 1970s. From late spring to fall, nearly the entire population is now
found in the upper inlet north of the forelands, with a range reduced to approximately 39
percent of the size documented in the late 1970s (Goetz et al. 2023). The recent annual
and semiannual aerial surveys (since 2008) found that approximately 83 percent of the
population inhabits the area between the Beluga River and Little Susitna River during the
survey period, typically conducted in early June. Some aerial survey counts were
performed in August, September, and October, finding minor differences in the numbers
of belugas in the upper inlet compared to June, reinforcing the importance of the upper
inlet habitat area (Young et al. 2023).
Two areas, consisting of 7,809 square kilometers (km2) of marine and estuarine
environments considered essential for the species’ survival and recovery, were designated
critical habitat. 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° N,
150.37° W) and the mouth of Threemile Creek (61.08.55° N, 151.04.40° 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). Critical Habitat Area 2 encompasses some of the fall
and winter feeding grounds in middle Cook Inlet.
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 occur 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. The transmitters collected data for

as little as a few days and up to 293 days with at least some data obtained each calendar
month. None of the tagged belugas left the inlet. All but three remained north of the
forelands for the duration of transmission, and those that traveled south did so only
briefly (Shelden et al. 2018).
In the winter, belugas are more widely dispersed based on aerial surveys,
opportunistic sighting reports, and tagging results, with animals found between Kalgin
Island and Point Possession. In November, beluga whales remained in Knik Arm,
Turnagain Arm, and Chickaloon Bay, similar to locations observed in September. Later
in winter (January into March), belugas were sighted near Kalgin Island and in deeper
waters offshore. However, even when ice cover exceeds 90 percent in February and
March, belugas travel into Knik Arm and Turnagain Arm (Hobbs et al. 2005).
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 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.
Using the June aerial survey data from 1994 to 2008, Goetz et al. (2012)
constructed a model of summer habitat preference for the entire Cook Inlet. The model
identified a positive geographic association with rivers with prey species (primarily
eulachon and salmon), shallow tidal flats, and sandy substrate and a negative association
with sources of anthropogenic disturbance. A heat map of the summer habitat was
generated, with 1 km2 cells ranging from 0 to 1.12 belugas per km2. The areas of highest
concentration were the Susitna River delta (from the Beluga River to the Little Susitna
River), upper Knik Arm, and Chickaloon Bay. Each area has generally large salmon runs,
shallow tidal flats, and little anthropogenic disturbance. The location of the JRP and the
towing routes between the Rig Tenders Dock and the JRP are areas of predicted low
density in the summer months.
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).

Wild et al. (2023) delineated a Small and Resident Population BIA in Cook Inlet
that is active year-round and overlaps Furie’s proposed project area. The authors assigned
the BIA an importance score of 2, an intensity score of 2, a data support score of 3, and a
boundary certainty score of 2. These scores indicate that the BIA is of moderate
importance and intensity, the authors have high confidence that the population is small
and resident and in the abundance and range estimates of the population, and the
boundary certainty is medium (see Harrison et al. (2023) for additional information about
the scoring process used to identify BIAs).
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 protected species observers
(PSOs). Daily aerial surveys specifically for beluga whales were flown over the lower
Cook Inlet region, but no beluga whales were observed. In 2023, Hilcorp recorded 21
sightings of more than 125 beluga whales during aerial surveys and an additional 21

opportunistic sightings that included approximately 81 beluga whales (Horsley and
Larson, 2023). Hilcorp did not record any sightings of beluga whales from their rig-based
monitoring efforts (Horsley and Larson, 2023)
Killer Whale
Killer whales from the Alaska Resident stock and the Gulf of Alaska, Aleutian
Islands, and Bering Sea Transient stock occur in lower Cook Inlet but rarely in middle
and upper Cook Inlet. Recent studies have documented the movements of Alaska
Resident killer whales from the Bering Sea into the Gulf of Alaska as far north as
southern Kodiak Island (Muto et al. 2017).
Killer whales have been sighted near Homer and Port Graham in lower Cook Inlet
(Shelden et al. 2003, 2022; Rugh et al. 2005). Resident killer whales from pods often
sighted near Kenai Fjords and Prince William Sound have been occasionally
photographed in lower Cook Inlet (Shelden et al. 2003). The availability of salmon
influences when resident killer whales are more likely to be sighted in Cook Inlet. Killer
whales were observed in the Kachemak and English Bay three times during aerial
surveys conducted between 1993 and 2004 (Rugh et al. 2005). Transient killer whales
were increasingly reported to feed on belugas in the middle and upper Cook Inlet in the
1990s.
During the 2015 SAExploration seismic program near the North Foreland, two
killer whales were observed (Kendall et al. 2015, as cited in Weston and SLR 2022).
Killer whales were observed in lower Cook Inlet in 1994, 1997, 2001, 2005, 2010, 2012,
and 2022 during the NMFS aerial surveys (Shelden et al. 2013, 2022). Eleven killer
whale strandings have been reported in Turnagain Arm: six in May 1991 and five in
August 1993. During the Hilcorp lower Cook Inlet seismic survey in the fall of 2019, 21
killer whales were documented (Fairweather Science 2020). Throughout 4 months of
observation in 2018 during the CIPL project in middle Cook Inlet, no killer whales were

observed (Sitkiewicz et al. 2018). In September 2021, two killer whales were
documented in Knik Arm in upper Cook Inlet, near the POA (61N 2022a). Hilcorp did
not record any sightings of fin whales from their aerial or rig-based monitoring efforts in
2023 (Horsley and Larson 2023).
Pacific White-Sided Dolphin
Pacific white-sided dolphins are common in the Gulf of Alaska's pelagic waters
and Alaska's nearshore areas, British Columbia, and Washington (Ferrero and Walker
1996, as cited in Muto et al. 2022). They do not typically occur in Cook Inlet, but in
2019, Castellote et al. (2020) documented short durations of Pacific white-sided dolphin
presence using passive acoustic recorders near Iniskin Bay (6 minutes) and at an offshore
mooring located approximately midway between Port Graham and Iniskin Bay (51
minutes). Detections of vocalizations typically lasted on the order of minutes, suggesting
the animals did not remain in the area and/or continue vocalizing for extended durations.
Visual monitoring conducted during the same period by marine mammal observers on
seismic vessels near the offshore recorder did not detect any Pacific white-sided dolphins
(Fairweather Science 2020). These observational data, combined with anecdotal
information, indicate that there is a small potential for Pacific white-sided dolphins to
occur in the Project area. On May 7, 2014, Apache Alaska observed three Pacific whitesided dolphins during an aerial survey near Kenai. This is one of the only recorded visual
observations of Pacific white-sided dolphins in Cook Inlet; they have not been reported in
groups as large as those estimated in other parts of Alaska (e.g. 92 animals in NMFS’
IHAs for Tongass Narrows).
Harbor Porpoise
Harbor porpoises prefer shallow coastal waters less than 100 m in depth (Hobbs
and Waite 2010). They are common in nearshore areas of the Gulf of Alaska, Shelikof
Strait, and lower Cook Inlet (Dahlheim et al. 2000). Harbor porpoises are often observed

in lower Cook Inlet in Kachemak Bay and from Cape Douglas to the West Foreland
(Rugh et al. 2005).
Harbor porpoises have been observed during most aerial surveys conducted in
Cook Inlet since 1993. They are frequently documented in Chinitna and Tuxedni Bays on
the west side of lower Cook Inlet (Rugh et al. 2005), with smaller numbers observed in
upper Cook Inlet between April and October. There were 137 groups comprised of 190
individuals documented between May and August during Apache’s 2012 seismic
program (Lomac-MacNair et al. 2013). Kendall et al. (2015, as cited in Weston and SLR
2022) documented 52 groups comprised of 65 individuals north of the Forelands during
SAExploration’s 2015 seismic survey. Two groups totaling three harbor porpoises were
observed in the fall of 2019 during Hilcorp’s lower Cook Inlet seismic survey
(Fairweather Science 2020). Four monitoring events were conducted at the POA in
Anchorage between April 2020 and August 2022, during which 42 groups of harbor
porpoises comprised of 50 individual porpoises were documented over 285 days of
observation (61N 2021, 2022a, 2022b, and 2022c). One harbor porpoise was observed
during Hilcorp’s monitoring boat-based monitoring efforts in June 2023 (Horsley and
Larson 2023).
Dall's Porpoise
The Dall’s porpoise range in Alaska includes lower Cook Inlet, but very few
sightings have been reported in upper Cook Inlet. Observations have been documented
near Kachemak Bay and Anchor Point (Owl Ridge 2014; BOEM 2015). 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). In August 2015,
one Dall’s porpoise was reported in the mid-inlet north of Nikiski during
SAExploration’s seismic program (Kendall et al. 2015 as cited in Weston and SLR
2022). During aerial surveys in Cook Inlet, they were observed in Iniskin Bay, Barren

Island, Elizabeth Island, and Kamishak Bay (Shelden et al. 2013). Ten groups totaling 30
Dall’s porpoises were observed in the fall of 2019 during Hilcorp’s lower Cook Inlet
seismic survey (Fairweather Science 2020). No Dall's porpoises were observed during
the CIPL project monitoring program in middle Cook Inlet in 2018 (Sitkiewicz et al.
2018). Hilcorp recorded one sighting of a Dall’s porpoise from their rig-based monitoring
efforts in the project area in 2023 (Horsley and Larson, 2023).
Steller Sea Lion
Most Steller sea lions in Cook Inlet occur south of Anchor Point on the east side
of lower Cook Inlet, with concentrations near haulout sites at Shaw Island and Elizabeth
Island and by Chinitna Bay and Iniskin Bay on the west side (Rugh et al. 2005). Steller
sea lions are rarely seen in upper Cook Inlet (Nemeth et al. 2007). About 3,600 sea lions
use haulout sites in the lower Cook Inlet area (Sweeney et al. 2017), with additional
individuals venturing into the area to forage. There is no designated critical habitat for
Steller sea lions in the mid- or upper inlet, nor are there any known BIAs for Steller sea
lions within the project area.
Several surveys and monitoring programs have documented Steller sea lions
throughout Cook Inlet, including in upper Cook Inlet in 2012 (Lomac-MacNair et al.
2013), near Cape Starichkof in 2013 (Owl Ridge 2014), in middle and lower Cook Inlet
in 2015 (Kendall et al. 2015, as cited in Weston and SLR 2022), in middle Cook Inlet in
2018 (Sitkiewicz et al. 2018), in lower Cook Inlet in 2019 (Fairweather Science 2020),
and near the Port of Alaska (POA) in Anchorage in 2020, 2021, and 2022 (61N 2021,
2022a, 2022b, and 2022c).
California Sea Lion
The few California sea lions observed in Alaska typically do not travel further
north than Southeast Alaska. They are often associated with Steller sea lion haulouts and
rookeries (Maniscalco et al. 2004). Sightings in Cook Inlet are rare, with two documented

during the Apache 2012 seismic survey (Lomac-MacNair et al. 2013) and anecdotal
sightings in Kachemak Bay. None were sighted during the 2019 Hilcorp lower Cook Inlet
seismic survey (Fairweather Science 2020), the CIPL project in 2018 (Sitkiewicz et al.
2018), or the 2023 Hilcorp aerial or rig-based monitoring efforts (Horsley and Larson,
2023).
Harbor Seal
In the spring and summer, harbor seals display an affinity for coastal haulout
areas for feeding, breeding, pupping, and molting, while ranging further offshore and
outside of Cook Inlet during the winter. High-density areas include Kachemak Bay,
Iniskin Bay, Iliamna Bay, Kamishak Bay, Cape Douglas, and Shelikof Strait. Up to a few
hundred seals seasonally occur in middle and upper Cook Inlet (Rugh et al. 2005), with
the highest concentrations found near the Susitna River during eulachon and salmon runs
(Nemeth et al. 2007; Boveng et al. 2012), but most remain south of the forelands
(Boveng et al. 2012).
More than 200 haulout sites are documented in lower Cook Inlet (Montgomery et
al. 2007) and 18 in middle and upper Cook Inlet (London et al. 2015). Of the 18 in
middle and upper Cook Inlet, nine are considered “key haulout” locations where
aggregations of 50 or more harbor seals have been documented. Seven key haulouts are
in the Susitna River delta, and two are near the Chickaloon River. The two haulout
locations closest to the JRP are located at Middle Ground Shoal, which becomes
inundated with water at most high tides (London et al. 2015).
Harbor seals have been sighted in Cook Inlet during every year of the aerial
surveys conducted by NMFS and during all recent mitigation and monitoring programs in
lower, middle, and upper Cook Inlet (61N 2021, 2022a, 2022b, and 2022c; Fairweather
Science 2020; Kendall et al. 2015 as cited in Weston and SLR 2022; Lomac-MacNair et
al. 2013, 2014; Sitkiewicz et al. 2018).

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 dB threshold from the normalized composite audiograms, with the
exception for lower limits for low-frequency cetaceans where the lower bound was
deemed to be biologically implausible and the lower bound from Southall et al. (2007)
retained. Marine mammal hearing groups and their associated hearing ranges are
provided in table 4.

Table 4 – Marine Mammal Hearing Groups (NMFS, 2018)
Hearing Group
Low-frequency (LF) cetaceans
(baleen whales)

Generalized Hearing
Range*
7 Hz to 35 kHz

Mid-frequency (MF) cetaceans
(dolphins, toothed whales, beaked whales, bottlenose
whales)

150 Hz to 160 kHz

High-frequency (HF) cetaceans
(true porpoises, Kogia, river dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L. australis)

275 Hz to 160 kHz

Phocid pinnipeds (PW) (underwater)
(true seals)

50 Hz to 86 kHz

Otariid pinnipeds (OW) (underwater)
(sea lions and fur seals)

60 Hz to 39 kHz

* 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 (Hemilä et al. 2006; Kastelein et al. 2009; Reichmuth et al. 2013). This
division between phocid and otariid pinnipeds is now reflected in the updated hearing
groups proposed in Southall et al. (2019).
For more detail concerning these groups and associated frequency ranges, please
see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their Habitat
This section provides a discussion of the ways in which components of the
specified activity may impact marine mammals and their habitat. The Estimated Take of
Marine Mammals 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 of Marine Mammals section, and the Proposed Mitigation section, to
draw conclusions regarding the likely impacts of these activities on the reproductive
success or survivorship of individuals and whether those impacts are reasonably expected
to, or reasonably likely to, adversely affect the species or stock through effects on annual
rates of recruitment or survival.
Description of Sound Sources
The marine soundscape is comprised of both ambient and anthropogenic sounds.
Ambient sound is defined as the all-encompassing sound in a given place and is usually a
composite of sound from many sources both near and far (ANSI 1995). The sound level
of an area is defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., waves, wind, precipitation,
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced by marine
mammals, fish, and invertebrates), and anthropogenic sound (e.g., vessels, dredging,
aircraft, construction).
The sum of the various natural and anthropogenic sound sources at any given
location and time—which comprise “ambient” or “background” sound—depends not
only on the source levels (as determined by current weather conditions and levels of
biological and shipping activity) but also on the ability of sound to propagate through the
environment. In turn, sound propagation is dependent on the spatially and temporally
varying properties of the water column and sea floor, and is frequency-dependent. As a
result of the dependence on a large number of varying factors, ambient sound levels can
be expected to vary widely over both coarse and fine spatial and temporal scales. Sound
levels at a given frequency and location can vary by 10–20 dB from day to day
(Richardson et al. 1995). The result is that, depending on the source type and its intensity,

sound from a specified activity may be a negligible addition to the local environment or
could form a distinctive signal that may affect marine mammals.
The proposed project includes the use of three to four tugs towing a jack-up rig as
well as impact pile driving of conductor piles. The sounds produced by these activities
fall into one of two general sound types: impulsive and non-impulsive. Impulsive sounds
(e.g., explosions, sonic booms, impact pile driving) are typically transient, brief (less than
1 second), broadband, and consist of high peak sound pressure with rapid rise time and
rapid decay (ANSI 1986; NIOSH 1998; NMFS 2018). Non-impulsive sounds (e.g.,
machinery operations such as drilling or dredging, vibratory pile driving, underwater
chainsaws, and active sonar systems) can be broadband, narrowband or tonal, brief or
prolonged (continuous or intermittent), and typically do not have the high peak sound
pressure with rise/decay time that impulsive sounds do (ANSI 1995; NIOSH 1998;
NMFS 2018). The distinction between impulsive and non-impulsive sound sources is
important because they have differing potential to cause physical effects, particularly
with regard to hearing (e.g., Ward 1997 in Southall et al. 2007).
An impact hammer that operates by repeatedly dropping and/or pushing a heavy
piston onto a pile to drive the pile into the substrate. Sound generated by impact hammers
is considered impulsive.
Towing the rig would emit consistent low levels of noise into a small portion of
Cook Inlet for an extended period of time. Furie’s tugging and positioning activities
would occur for approximately 20-25 hours over 2 days at the beginning and end of the
drilling season in Year 1 and 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 rig are less well
documented. The various scenarios that may occur during this project extend from tugs in
a stationary mode positioning the drill rig to pulling the rig at nearly full power against

strong tides. Our assessments of the potential for harassment of marine mammals
incidental to Furie’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., tug configuration and pile
driving equipment) as well as associated noise with pile driving and the moving and
positioning of the 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 (for tugging, when making multiple
positioning attempts) and noise created when moving and positioning the rig using tugs,
as well as impact installation of the conductor piles. Essentially, the project area will
become a concentrated work area in an otherwise non-industrial setting for a period of
several days.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic environment from tugs
and pile driving equipment is the primary means by which marine mammals may be
harassed from Furie’s specified activities. In general, animals exposed to natural or
anthropogenic sound may experience physical and psychological effects, ranging in
magnitude from none to severe (Southall et al. 2007). Generally, exposure to pile driving
and tugging has the potential to result in auditory threshold shifts (TS) and behavioral
disturbance (e.g., avoidance, temporary cessation of foraging and vocalizing, changes in
dive behavior). Exposure to anthropogenic noise can also lead to non-observable
physiological responses such as an increase in stress hormones. Additional noise in a

marine mammal's habitat can mask acoustic cues used by marine mammals to carry out
daily functions such as communication and predator and prey detection. The effects of
pile driving and tugging noise on marine mammals are dependent on several factors,
including, but not limited to, sound type (e.g., impulsive vs. non-impulsive), the species,
age and sex class (e.g., adult male vs. mother with calf), duration of exposure, the
distance between the sound source and the animal, received levels, behavior at time of
exposure, and previous history with exposure (Wartzok et al. 2003; Southall et al. 2007).
Here we discuss physical auditory effects (TSs) followed by behavioral effects and
potential impacts on habitat.
NMFS defines a noise-induced 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 TS 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, impact pile driving is treated as an impulsive source. The sounds produced by
tugs towing and positioning the 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 TS
approximates PTS onset (see NMFS 2018 for review). PTS levels for marine mammals
are estimates, because there are limited empirical data measuring PTS in marine
mammals (e.g., Kastak et al. 2008), largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels inducing PTS are
not typically pursued or authorized (NMFS 2018).
Temporary Threshold Shift—TTS is 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 TS 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). As described in Finneran (2016), marine mammal studies have shown
the amount of TTS increases with cumulative sound exposure level (SELcum) in an
accelerating fashion: At low exposures with lower SELcum, the amount of TTS is typically
small and the growth curves have shallow slopes. At exposures with higher SELcum, the
growth curves become steeper and approach linear relationships with the noise SEL.
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.
Many studies have examined noise-induced hearing loss in marine mammals (see
Finneran (2015) and Southall et al. (2019) for summaries). For cetaceans, published data
on the onset of TTS are limited to the captive bottlenose dolphin (Tursiops truncatus),
beluga whale, harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis), and for pinnipeds in water, measurements of TTS are limited to harbor
seals, elephant seals (Mirounga angustirostris), and California sea lions. These studies
examine hearing thresholds measured in marine mammals before and after exposure to
intense sounds. The difference between the pre-exposure and post-exposure thresholds
can be used to determine the amount of TS at various post-exposure times. The amount
and onset of TTS depends on the exposure frequency. Sounds at low frequencies, well
below the region of best sensitivity, are less hazardous than those at higher frequencies,
near the region of best sensitivity (Finneran and Schlundt 2013). At low frequencies,
onset-TTS exposure levels are higher compared to those in the region of best sensitivity
(i.e., a low frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor seals (Kastelein et al.
2019a, 2019b, 2020a, 2020b). In addition, TTS can accumulate across multiple
exposures, but the resulting TTS will be less than the TTS from a single, continuous

exposure with the same sound exposure level (SEL; Finneran et al. 2010; Kastelein et al.
2014; Kastelein et al. 2015a; Mooney et al. 2009). This means that TTS predictions
based on the total, cumulative SEL will overestimate the amount of TTS from
intermittent exposures such as sonars and impulsive sources. Nachtigall et al. (2018) and
Finneran (2018) describe the measurements of hearing sensitivity of multiple odontocete
species (bottlenose dolphin, harbor porpoise, beluga, and false killer whale (Pseudorca
crassidens)) when a relatively loud sound was preceded by a warning sound. These
captive animals were shown to reduce hearing sensitivity when warned of an impending
intense sound. Based on these experimental observations of captive animals, the authors
suggest that wild animals may dampen their hearing during prolonged exposures or if
conditioned to anticipate intense sounds. Another study showed that echolocating animals
(including odontocetes) might have anatomical specializations that might allow for
conditioned hearing reduction and filtering of low-frequency ambient noise, including
increased stiffness and control of middle ear structures and placement of inner ear
structures (Ketten et al. 2021). Data available on noise-induced hearing loss for
mysticetes are currently lacking (NMFS 2018).
Activities for this project include tugging and impact pile driving. Tugging is a
transient activity, and there would likely be pauses in pile driving during each day that it
occurs. Given the nature of these activities and the fact that many marine mammals are
likely moving through the project areas and not remaining for extended periods of time,
the potential for TS declines.
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 (μPa) rms to predict the onset of Level B harassment from impulse noises
(such as impact pile driving), and 120 dB re 1 μPa (rms) for continuous noises (such as
operating dynamic positioning (DP) thrusters), although in certain circumstances there
may be contextual factors that alter our assessment. Furie’s activity includes the use of
continuous (tug towing and positioning) and impulsive (impact pile driving) sources, and
therefore the RMS SPL thresholds of 120 and 160 dB re 1 μPa are applicable.
Disturbance may result in changing durations of surfacing and dives, number of
blows per surfacing, moving direction and/or speed, reduced/increased vocal activities;
changing/cessation of certain behavioral activities (such as socializing or feeding), visible
startle response or aggressive behavior (such as tail/fluke slapping or jaw clapping),
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 pile driving and 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 or impulsive 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, gray 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 noiseproducing 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 nature of tugging. Potential for PTS and
TTS due to pile driving is discussed further in the Estimated Take section.
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 rig
configuration as well as conductor pipe pile driving, 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 tug 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 rig configuration (e.g., difficult to maneuver, potential need to
operate at night) and pile driving activities means it is possible that take could occur over
the total estimated period of activities.
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 fitness for 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 frequency band for noise 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 5 hours per positioning attempt, and up to two positioning
attempts at the same site. Further, noise generated by impact pile driving will be
intermittent and will occur over a maximum of 2 days per year.
Marine Mammal Habitat Effects
Furie’s proposed activities could have localized, temporary impacts on marine
mammal habitat, including prey, by increasing in-water sound pressure levels and, for
pile driving, slightly decreasing water quality. Increased noise levels may affect acoustic
habitat and adversely affect marine mammal prey in the vicinity of the project areas (see

discussion below). Elevated levels of underwater noise would ensonify the project areas
where both fishes and mammals occur and could affect foraging success.
The total seafloor area likely impacted by the pile driving associated with the
project is relatively small compared to the available habitat in Cook Inlet. Avoidance by
potential prey (i.e., fish) of the immediate area due to the temporary loss of this foraging
habitat is possible. The duration of fish and marine mammal avoidance of this area after
pile driving stops is unknown, but a rapid return to normal recruitment, distribution, and
behavior is anticipated. Any behavioral avoidance by fish or marine mammals of the
disturbed area would still leave significantly large areas of fish and marine mammal
foraging habitat in the nearby vicinity.
Increased turbidity near the seafloor is not anticipated, as installation of the
conductor piles would occur within the monopod leg of the platform.
Effects on Potential Prey
Sound may affect marine mammals through impacts on the abundance, behavior,
or distribution of prey species (e.g., fish). Marine mammal prey varies by species, season,
and location. Here, we describe studies regarding the effects of noise on known marine
mammal prey.
Fish utilize the soundscape and components of sound in their environment to
perform important functions such as foraging, predator avoidance, mating, and spawning
(e.g., Zelick and Mann 1999; Fay 2009). Depending on their hearing anatomy and
peripheral sensory structures, which vary among species, fishes hear sounds using
pressure and particle motion sensitivity capabilities and detect the motion of surrounding
water (Fay et al. 2008). The potential effects of noise on fishes depends on the
overlapping frequency range, distance from the sound source, water depth of exposure,
and species-specific hearing sensitivity, anatomy, and physiology. Key impacts to fishes

may include behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent low-frequency
sounds, and behavioral responses such as flight or avoidance are the most likely effects.
Short duration, sharp sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the physiological state of the fish,
past exposures, motivation (e.g., feeding, spawning, migration), and other environmental
factors. Hastings and Popper (2005) identified several studies that suggest fish may
relocate to avoid certain areas of sound energy. Additional studies have documented
effects of pile driving on fish; several are based on studies in support of large, multiyear
bridge construction projects (e.g., Scholik and Yan 2001, 2002; Popper and Hastings
2009). Several studies have demonstrated that impulse sounds might affect the
distribution and behavior of some fishes, potentially impacting foraging opportunities or
increasing energetic costs (e.g., Fewtrell and McCauley 2012; Pearson et al. 1992;
Skalski et al. 1992; Santulli et al. 1999; Paxton et al. 2017). However, some studies have
shown no or slight reaction to impulse sounds (e.g., Pena et al. 2013; Wardle et al. 2001;
Jorgenson and Gyselman 2009).
SPLs of sufficient strength have been known to cause injury to fish and fish
mortality. However, in most fish species, hair cells in the ear continuously regenerate and
loss of auditory function likely is restored when damaged cells are replaced with new
cells. Halvorsen et al. (2012a) showed that a TTS of 4–6 dB was recoverable within 24
hours for one species. Impacts would be most severe when the individual fish is close to
the source and when the duration of exposure is long. Injury caused by barotrauma can
range from slight to severe and can cause death, and is most likely for fish with swim
bladders. Barotrauma injuries have been documented during controlled exposure to
impact pile driving (Halvorsen et al. 2012b; Casper et al. 2013).

For pile driving, the most likely impact to fishes at the project site would be
temporary avoidance of the area. The duration of fish avoidance of this area after pile
driving stops is unknown, but a rapid return to normal recruitment, distribution, and
behavior is anticipated. For tugging activities, much of the tugging would be mobile
during transport of the rig, and the tugging noise that occurs during rig positioning would
be temporary, similar to pile driving.
In summary, given the short daily duration of sound associated with individual
pile driving events and the relatively small areas being affected, as well as the temporary
and mostly transitory nature of the tugging, Furie’s activities are not likely to have a
permanent, adverse effect on any fish habitat, or populations of fish species. Any
behavioral avoidance by fish of the disturbed area would still leave significantly large
areas of fish and marine mammal foraging habitat in the nearby vicinity. Thus, we
conclude that impacts of the specified activities are not likely to have more than shortterm adverse effects on any prey habitat or populations of prey species. Further, any
impacts to marine mammal habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to adverse impacts on
their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes proposed for
authorization through the IHA, which will inform NMFS’ consideration of “small
numbers,” the negligible impact determinations, and impacts on subsistence uses.
Harassment is the only type of take expected to result from these activities.
Except with respect to certain activities not pertinent here, section 3(18) of the MMPA
defines “harassment” as any act of pursuit, torment, or annoyance, which (i) has the
potential to injure a marine mammal or marine mammal stock in the wild (Level A
harassment); or (ii) has the potential to disturb a marine mammal or marine mammal

stock in the wild by causing disruption of behavioral patterns, including, but not limited
to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).
Takes proposed for authorization would primarily be by Level B harassment, as
use of the acoustic sources (i.e., pile driving and tug towing and positioning) has the
potential to result in disruption of behavioral patterns for individual marine mammals.
We note here that given the slow, predictable, and generally straight path of tug towing
and positioning, the likelihood of a resulting disruption of marine mammal behavioral
patterns that would qualify as harassment is considered relatively low, however, at the
request of the applicant, we have quantified the potential take from this activity, analyzed
the impacts, and proposed its authorization. There is also some potential for auditory
injury (Level A harassment) to result to phocids because of species occurrence and
because predicted auditory injury zones are larger than for mid-frequency and otariid
species. Auditory injury is unlikely to occur for low-frequency, mid-frequency, highfrequency, or otariid species. The proposed mitigation and monitoring measures are
expected to minimize the severity of the taking to the extent practicable.
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 B harassment) or to incur PTS of
some degree (equated to Level A harassment).
Level B Harassment – Though significantly driven by received level, the onset of
behavioral disturbance from anthropogenic noise exposure is also informed to varying
degrees by other factors related to the source or exposure context (e.g., frequency,
predictability, duty cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area, predators in the area),
and the receiving animals (hearing, motivation, experience, demography, life stage,
depth) and can be difficult to predict (e.g., Southall et al. 2007, 2021, Ellison et al. 2012).
Based on what the available science indicates and the practical need to use a threshold
based on a metric that is both predictable and measurable for most activities, NMFS
typically uses a generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS generally predicts that marine mammals are likely
to be behaviorally harassed in a manner considered to be Level B harassment when
exposed to underwater anthropogenic noise above root-mean-squared pressure received
levels (RMS SPL) of 120 dB re 1 μPa for continuous (e.g., vibratory pile driving,
drilling) and above RMS SPL 160 dB re 1 μPa for non-explosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific sonar) sources. Generally speaking, Level B
harassment take estimates based on these thresholds are expected to include any likely
takes by TTS as, in most cases, the likelihood of TTS occurs at distances from the source
smaller than those at which behavioral harassment is likely. TTS of a sufficient degree

can manifest as behavioral harassment, as reduced hearing sensitivity and the potential
reduced opportunities to detect important signals (conspecific communication, predators,
prey) may result in changes in behavior patterns that would not otherwise occur.
Furie’s proposed activity includes the use of continuous (tugs towing rig) and
impulsive (impact pile driving) sources, and therefore the RMS SPL thresholds of 120
and 160 dB re 1 μPa are applicable.
Level A harassment – NMFS’ Technical Guidance for Assessing the Effects of
Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) (Technical Guidance,
2018) identifies dual criteria to assess auditory injury (Level A harassment) to five
different marine mammal groups (based on hearing sensitivity) as a result of exposure to
noise from two different types of sources (impulsive or non-impulsive). Furie’s proposed
activity includes the use of impulsive (impact pile driving) and non-impulsive (tugs
towing and positioning 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:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammalacoustic-technical-guidance.
Table 5 – Thresholds Identifying the Onset of PTS
PTS Onset Acoustic Thresholds*
(Received Level)
Hearing Group

Impulsive

Non-impulsive

Low-Frequency (LF)
Cetaceans

Cell 1
Lpk,flat: 219 dB
LE,LF,24h: 183 dB

Cell 2
LE,LF,24h: 199 dB

Mid-Frequency (MF)
Cetaceans

Cell 3
Lpk,flat: 230 dB
LE,MF,24h: 185 dB

Cell 4
LE,MF,24h: 198 dB

High-Frequency (HF)
Cetaceans

Cell 5
Lpk,flat: 202 dB
LE,HF,24h: 155 dB

Cell 6
LE,HF,24h: 173 dB

Phocid Pinnipeds (PW)
(Underwater)

Cell 7
Lpk,flat: 218 dB
LE,PW,24h: 185 dB

Cell 8
LE,PW,24h: 201 dB

Otariid Pinnipeds (OW)
(Underwater)

Cell 9
Lpk,flat: 232 dB
LE,OW,24h: 203 dB

Cell 10
LE,OW,24h: 219 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 µPa, and cumulative sound exposure level
(LE) has a reference value of 1µPa2s. In this table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI
as incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the
subscript “flat” is being included to indicate peak sound pressure should be flat weighted or unweighted
within the generalized hearing range. The subscript associated with cumulative sound exposure level
thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF
cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The
cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e., varying
exposure levels and durations, duty cycle). When possible, it is valuable for action proponents to
indicate the conditions under which these acoustic thresholds will be exceeded.

Ensonified Area
Here, we describe operational and environmental parameters of the activity that
are used in estimating the area ensonified above the acoustic thresholds, including source
levels and transmission loss (TL) coefficient.
The sound field in the project area is the existing background noise plus
additional noise from the proposed project. Marine mammals are expected to be affected
via sound generated by the primary components of the project (i.e., pile driving and tug
towing and positioning). The calculated distance to the farthest Level B harassment
isopleth is approximately 4,483 m (2.8 miles (mi)).
The project includes impact installation of up to two 20-inch conductor pipe piles
in each year. The monopod leg of the JRP will encase the well slot, which will encase the
conductor pipes; therefore, some attenuation is expected during conductor pipe pile
installation. However, water-filled isolation casings (such as the well slot and caisson at

the JRP) are expected to provide limited sound attenuation (Caltrans 2015). Due to the
well slot's reflective surfaces and the monopod leg's caisson inside the JRP, some
attenuation of the impact noise is expected before reaching the open water. However,
lacking project-specific empirical data for a 20-inch conductor installed within a well slot
located within a monopod leg, the unaltered sound source levels (SSLs) from U.S. Navy
(2015) are used to calculate Level A harassment and Level B harassment isopleths.
For tug activities, as described in 87 FR 27597 (May 9, 2022), Hilcorp conducted
a literature review of available source level data for tugs under load in varying power
output scenarios. Table 6 below provides values of measured source levels for tugs
varying from 2,000 to 8,200 horsepower. For the purposes of this table, berthing
activities could include tugs either pushing or pulling a load. The SSLs appear correlated
to speed and power output, with full power output and higher speeds generating more
propeller cavitation and greater SSLs 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 2022 IHA application, available at
https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llcoil-and-gas-activities-cook-inlet-alaska-0.
Table 6-- Literature Values of Measured Tug Source Levels
Vessel

Vessel
Length
(m)

Speed
(knots)

Activity

Eagle

9.6

Valor

8.4

Lela Joy

4.9

Pacific Eagle

8.2

Shannon

9.3

Towing
barge
Towing
barge
Towing
barge
Towing
barge
Towing
barge

Source
Level @1
m (re: 1
µPa)
Horsepower

Reference

6,770

Bassett et al.
168

2,400

2,000

2,000

2,000

James T
Quigg
Island Scout

7.9

5.8

Chief

11.4

Lauren Foss

N/A

Seaspan
Resolution

N/A

Seaspan
Resolution

N/A

Towing
barge
Towing
barge
Towing
barge
Berthing
barge
Berthing
at half
power
Berthing
at full
power

2,000

4,800

8,200

8,200

6,000

6,000

Austin et al.
2013
Roberts
Bank
Terminal 2
Technical
Report 2014

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 Furie’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 μPa 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 μPa at 1 m; the 25th percentile was 179.0 dB re 1 μPa at 1 m, and 5th
percentile source levels were 184.9 dB re 1 μPa at 1 m.
Based solely on the literature review, a source level of 180 dB for a single tug
under load would be appropriate. However, Furie’s use of a three tug configuration
would increase the literature source level to approximately 185 dB at 1 m (Lawrence et
al. 2022, as cited in Weston and SLR 2022).
As described above in the Detailed Description of the Specific Activity section,
based on in situ measurements of Hilcorp's tug and a review of the available literature of
tugs under load described above, NMFS finds that a source level of 185 dB re 1 µPa is
appropriate for Furie’s three tug configuration for towing the rig.

As described above in the Detailed Description of the Specific Activity section,
Furie may need to use four tugs to position the rig at the JRP. The SPLRMS of 185 dB for
three tugs at 50 percent power implies each tug individually has a source level of 180.2
dB SPLrms because the addition of three equal-intensity sound signals adds 4.8 dB to the
sound level of a single source (Engineering Toolbox 2023). Each doubling of sound
intensity adds 3 dB to the baseline (Engineering Toolbox 2023), and four tugs represents
two doublings of a single source. Therefore, adding 6 dB to the 180.2 dB baseline results
in an expected SSL of 186.2 dB rms SPL for the use of four tugs. Source levels for each
activity are presented in table 7.
Table 7-- SSLs for Project Activities
Sound Source

SSL
SEL

SPLRMS

3 tugs at 50 percent power

185 dB at 1 m

4 tugs at 50 percent power

186.2 dB at 1 m

Conductor pipe pile (20 in, impact)

184 dB at 1 m

193 dB at 10 m

Several factors will determine the duration that the tugboats are towing the
Enterprise 151, including the origin and destination of the towing route (e.g., Rig Tenders
Dock, the JRP, one of Hilcorp’s platforms) and the tidal conditions. The power output
will be variable and influenced by the prevailing wind direction and velocity, the current
velocity, and the tidal stage. To the extent feasible, transport will be timed with the tide to
minimize towing duration and power output.
TL is the decrease in acoustic intensity as an acoustic pressure wave propagates
out from a source. TL parameters vary with frequency, temperature, sea conditions,
current, source and receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater

TL is:
TL = B * Log10 (R1/R2),
where
TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement
Absent site-specific acoustical monitoring with differing measured TL, a practical
spreading value of 15 is used as the TL coefficient in the above formula. Site-specific TL
data for pile driving at the JRP site are not available; therefore, the default coefficient of
15 is used to determine the distances to the Level A harassment and Level B harassment
thresholds for conductor pile driving.
For its tugging activities, Hilcorp contracted SLR Consulting to model the extent
of the Level B harassment isopleth as well as the extent of the Level A harassment
isopleth for their proposed tugging using three tugs. Rather than applying practical
spreading loss, SLR Consulting 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 Hilcorp’s specific well sites. Modeling was
conducted using dBSea software. The fluid parabolic equation modeling algorithm was
used with 5 Padé terms (see pg. 57 in Hilcorp's application, available at
https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llcoil-and-gas-activities-cook-inlet-alaska-0, for more detail) to calculate the TL 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) TL 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 TL were combined
to obtain the received levels as a function of range, depth, and frequency; and (5) The
overall received levels were calculated at a 1 m depth resolution along each propagation
path by summing all frequency band spectral levels.
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 m 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
(available at https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorpalaska-llc-oil-and-gas-activities-cook-inlet-alaska-0). 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
(available at https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorpalaska-llc-oil-and-gas-activities-cook-inlet-alaska-0).
Detailed broadband sound TL modeling in dBSea used the source level of 185 dB
re 1 μPa 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.
Furie plans to use the tugs towing the rig for two functions, rig positioning and
towing. The activity was divided into two parts (stationary and mobile) and two
approaches were taken for modeling the relevant isopleths.
SLR’s model, described above, calculated the Level B harassment isopleth
propagating from three tugs towing a jack-up rig at 25 locations between Hilcorp
platforms and well sites and the Rig Tenders Dock in Nikiski, Alaska. The average Level
B harassment isopleth across all locations and seasons was determined to be 3,850 m
(Weston and SLR 2022). Given that Furie is conducting the same three tug activity as
Hilcorp, also in middle Cook Inlet, Furie estimates, and NMFS concurs, that 3,850 m is
also an appropriate estimate of its Level B harassment zone for tugging using three tugs.
Similarly, Hilcorp modeled Level A harassment zones for each hearing group; Furie
proposed using these Level A harassment zones for its towing and positioning activities
using three tugs, and NMFS concurs. These zones are included in table 8.
As described in the Description of Proposed Activity section, when positioning
the rig, Furie may use four tugs for up to 1 hour. Hilcorp did not model a Level B
harassment zone accounting for the use of four tugs. Furie estimated the Level B
harassment zones for tugging and positioning with four tugs using a sound source level of
186.2 dB and a TL of 18.129.
NMFS estimated the Level A harassment zones from the use of four tugs using its
User Spreadsheet and the Level A harassment zones modeled by Hilcorp for the use of
three tugs. First, NMFS calculated the Level A harassment zones for the three tug

scenario using the User Spreadsheet (sound source level of 185 dB, 5 hours of sound
production, and a propagation loss coefficient of 18.129). Next, NMFS calculated the
Level A harassment zones for the “combined scenario” (use of three tugs for 5 hours and
four tugs for 1 hour, combined). NMFS then calculated the ratio between the three tug
scenario and the combined scenario. For all hearing groups the combined scenario Level
A harassment isopleths are 13.8 percent larger than the three tug scenario. Rather than
using the Level A harassment isopleths for the combined scenario that were calculated
using the User Spreadsheet, NMFS applied a 13.8 percent increase to the three tug Level
A harassment isopleths modeled by Hilcorp, given that those isopleths are more
conservative than the isopleths NMFS calculated using the User Spreadsheet. The Level
A harassment isopleths that Furie will implement are included in table 10.
The Level B harassment isopleth from the use of four tugs is 4,483 m, as
described in Furie’s application and included in table 6, calculated using a sound source
level of 186.2 dB SPL. NMFS concurs and proposes a Level B harassment zone of 4,483
m for tugging and positioning using four tugs (table 10).
Table 8-- User Spreadsheet Inputs (Source Levels Provided in Table 7)
Source

Number of Strikes
per Pile

Number of Piles
per Day

Transmission
Loss Coefficient

Conductor pipe pile,
Day 1 (70 percent
installation)

6,100

0.7

Conductor pipe pile,
Day 2 (30 percent
installation)

0.3

Table 9-- Level A Harassment Isopleths Calculated Using NMFS’ User Spreadsheet,
and Used to Determine the Ratio between the Three Tug Scenario and Three and
Four Tugs Combined Scenario
Level A Harassment Isopleth (m)
Scenario

LowFrequency
Cetaceans

MidFrequency
Cetaceans

HighFrequency
Cetaceans

Phocid
Otariid
Pinnipeds Pinnipeds

Three Tug Scenario
Level A harassment
Isopleth

17.2

9.7

178.9

9.1

0.9

Combined Scenario
Level A harassment
Isopleth

19.6

11.0

203.6

10.3

1.0

The ensonified area associated with Level A harassment is more technically
challenging to predict due to the need to account for a duration component. Therefore,
NMFS developed an optional User Spreadsheet tool to accompany the Technical
Guidance that can be used to relatively simply predict an isopleth distance for use in
conjunction with marine mammal density or occurrence to help predict potential takes.
We note that because of some of the assumptions included in the methods underlying this
optional tool, we anticipate that the resulting isopleth estimates are typically
overestimates of some degree, which may result in an overestimate of potential take by
Level A harassment. However, this optional tool offers the best way to estimate isopleth
distances when more sophisticated modeling methods are not available or practical. For
stationary sources such as conductor pipe pile driving and rig positioning, the optional
User Spreadsheet tool predicts the distance at which, if a marine mammal remained at
that distance for the duration of the activity, it would be expected to incur PTS. For
mobile sources such as tugging, the optional User Spreadsheet tool predicts the closest
distance at which a stationary animal would not be expected to incur PTS if the sound
source traveled by the stationary animal in a straight line at a constant speed. Inputs used

in the optional User Spreadsheet tool, and the resulting estimated isopleths, are reported
below.
Table 10-- Level A Harassment and Level B Harassment Isopleths From Tugging
and Impact Pile Driving
Sound Source

Level A Harassment Isopleths (m)

Level B Harassment
Isopleths (m)

LF

MF

HF

PW

OW

Conductor pipe pile,
70 percent
installation

3,064

3,650

1,640

Conductor pipe pile,
30 percent
installation

1,742

2,075

68

Tugging/Positioning, 95
3 Tugs1

679

0

3,850

Tugging/Positioning, 108
4 Tugs2

773

1

4,483

1,585

1 These

zones are results from Hilcorp’s modeling.
otariids, Hilcorp’s model estimated a Level A harassment zone of 0 during tugging/positioning with
three tugs. Therefore, for four tugs, NMFS applied the Level A harassment zone calculating with the User
Spreadsheet.
2 For

Marine Mammal Occurrence
In this section we provide information about the occurrence of marine mammals,
including density or other relevant information which will inform the take calculations.
Densities for marine mammals in Cook Inlet were derived from NMFS' Marine
Mammal Laboratory (MML) aerial surveys, typically flown in June, from 2000 to 2018
(Rugh et al. 2005; Shelden et al. 2013, 2015, 2017, 2019). 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. (Note that while more recent surveys have been
conducted and published (Shelden et al. 2022; Goetz et al. 2023), the surveyed area was
not included in either report, therefore they were not used to calculate density). Density
was calculated by summing the total number of animals observed and dividing the

number sighted by the area surveyed. The total number of animals observed accounts for
both lower and upper Cook Inlet. There are no density estimates available for California
sea lions and Pacific white-sided dolphins in Cook Inlet, as they are so infrequently
sighted. Densities are presented in table 11.
Table 11-- Marine Mammal Densities
Species

Density (individuals/km2)

Humpback whale

0.00177

Minke whale

0.000009

Gray whale

0.000075

Fin whale

0.000311

Killer whale

0.000601

Beluga (Trading Bay)

0.004453–0.015053

Beluga (North Cook Inlet)

0.001664

Dall’s porpoise

0.000154

Harbor porpoise

0.004386

Pacific white-sided dolphin

Harbor seal

0.241401

Steller sea lion

0.007609

California sea lion

For the beluga whale density, Furie, and subsequently NMFS, used 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 Furie’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 and were carried forward to the take estimates. Likewise, when a

range is given, the higher end of the range was conservatively used to calculate take
estimates (i.e., Trading Bay in the Goetz model has a range of 0.004453 to 0.015053;
0.015053 was used for the take estimates).
Take Estimation
Here we describe how the information provided above is synthesized to produce a
quantitative estimate of the take that is reasonably likely to occur and proposed for
authorization in each IHA.
Year 1 IHA
As described above, Furie plans to conduct rig towing and positioning and may
install up to two conductor piles using an impact hammer in Year 1. To estimate take by
Level B harassment from tugging, for each species, Furie summed the estimated take for
towing the rig at the beginning of the season, positioning the rig, and towing the rig at the
end of the season. To estimate take for towing the rig (beginning and end of season),
Furie multiplied the area of the Level B harassment zone (316.1 km2; inclusive of the full
potential tug path of 35 km) by the species density (table 11). To estimate take for
positioning the rig, Furie multiplied the maximum area of the Level B harassment zone
(63.1 km2, four tugs) by the species density (table 11), by the number of potential
positioning attempts (two attempts). NMFS concurs that this method for estimating take
from tugging activities is appropriate.
To estimate take by Level B harassment from installation of conductor piles,
Furie multiplied the Level B harassment zone (7.98 km2) by the species density (table 11)
by the estimated number of days that conductor pile installation would occur (4 days, 2
per pile). The Level B harassment zone used in the calculation conservatively assumes 70
percent installation of a conductor pile on a given day, and therefore, on 2 of the 4 days
that conductor piles would be installed, the Level B harassment zone would likely be

smaller. NMFS concurs that this method for estimating take from pile driving activities is
appropriate.
NMFS summed the estimated take by Level B harassment from tugging and pile
driving activities for each species. For species where the total calculated take by Level B
harassment is less than the estimated group size for that species, NMFS rounded up the
take by Level B harassment proposed for authorization to the anticipated group size. Take
proposed for authorization during Year 1 activities is included in table 12.
Based on the analysis described above, NMFS does not propose to authorize take
by Level A harassment related to Furie’s tugging activity. For mobile tugging activity,
the distances to the PTS thresholds for high frequency cetaceans (the only hearing group
for which modeling results in a Level A harassment zone greater than 0 m) 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 for a long enough duration to incur PTS. For
stationary positioning of the rig, the PTS isopleths are up to 679 m for high frequency
cetaceans, but calculated with the assumption that an animal would remain within several
hundred meters of the rig for the full 5 hours of noise-producing activity which is
unlikely. Therefore, take by Level A harassment due to stationary or mobile tugging is
neither anticipated nor proposed for authorization.
For conductor pile installation, NMFS anticipates take by Level A harassment for
harbor seal only. For all other species, calculated take by Level A harassment takes is less
than one. Considering that along with the low likelihood that an individual of these
species would enter and remain within the Level A harassment zone for long enough to
incur PTS, particularly in consideration of implementation of required shutdown zones,
Furie did not request, nor does NMFS propose to authorize, take by Level
A harassment. For harbor seal, NMFS proposes to authorize three takes by Level A
harassment, conservatively rounded up from 2.7 Level A harassment takes calculated.

Table 12 -- Estimated Take by Level B Harassment, by Species, Activity, and in Total, Year 1
Species

Proposed
Take By Level
B Harassmenta

0.06

1.5

Rig Positioning, 4 Tugs

Conductor Pile Installation

Ensonified
Area (km2)

Calculated
Take by Level
B Harassment2

Ensonified
Area (km2)

Calculated
Take by
Level B
Harassment3

Ensonified
Area (km2)

Calculated
Take by
Level B
Harassment4

1.2

63.1

0.2

7.89

Humpback
whale

Total Year 1 Estimated Take by
Level B Harassment

Rig Tow, 3 Tugs

316.1

Minke
whale

0.006

0.001

0.0003

0.007

Gray whale

0.04

0.009

0.002

0.05

Fin whale

0.2

0.04

0.01

0.3

Killer
whale

0.4

0.08

0.02

0.5

Beluga
(Trading
Bay)

0.5

0.2

0.05

0.8

Beluga
(NCI)

4.8

NA

NA

4.8

Dall’s
porpoise

0.1

0.01

0.005

0.1

Harbor
porpoise

2.8

0.3

0.1

3.2

Pacific
white-sided
dolphin

0.000

0.000

0.000

0.000

Harbor seal

152.6

15.2

7.6

175.4

Steller sea
lion

4.8

0.5

0.2

5.5

California
sea lion

0.000

0.000

0.000

0.000

1 This

zone assumes a 35 km towing distance (the farthest potential distance that Furie may need to tow the rig).
Level B harassment zone area x density x 2 (towing at beginning and end of season), with the exception of Cook Inlet beluga whale. For Cook Inlet beluga
whale, Furie used the Trading Bay density for the initial rig tow since the density is predicted to be higher there than in the North Cook Inlet Lease Unit (located
offshore in middle Cook Inlet), and Furie may tug the rig though that area. Furie used the NCI density to estimate take for the end of season tow. NMFS concurs
and has used these two separate densities in its analysis.
3 Level B harassment zone (63.1 km2) x species density (table 11), x number of potential positioning attempts (2).
4 Level B harassment zone (7.89 km2) x species density (table 11) x estimated number of days that conductor pile installation would occur (4).
Explanations for species for which take proposed for authorization is greater than
calculated take are included below.
Several recent surveys and monitoring programs have documented groups of
humpback whales ranging up to 14 whales in size. During the annual survey, Shelden et
al. (2022) recorded a group of three humpback whales west of Kachemak Bay in June of
2022. Past annual aerial surveys have documented groups up to 12 in number (Shelden et
al. 2013, 2015, 2016, 2019). During Hilcorp’s lower Cook Inlet seismic survey, group
size ranged from 1 to 14 (Fairweather Science 2020). During monitoring of the Harvest
Alaska CIPL project (the closest to Furie’s Action Area), two sightings of three
humpbacks were reported. During construction of the JRP in 2015, a group of 6 to 10
unidentified whales, thought to be either gray whales or humpbacks, was observed
approximately 15 km northeast of the platform (Jacobs 2015). 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). Furie requested, and NMFS is
proposing to authorize, three takes of humpback whale by Level B harassment in Year 1.
This estimate accounts for the potential of take of a group of two animals and a solitary
animal.
Groups of up to three minke whales have been recorded in recent years, including
one group of three southeast of Kalgin Island (Lomac-MacNair et al. 2014). Other recent
surveys in Cook Inlet typically have documented minkes traveling alone (Shelden et al.
2013, 2015, 2017; Kendall et al. 2015, as cited in Weston and SLR 2022; 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, Furie requested,
and NMFS is proposing to authorize, three takes of minke whale by Level B harassment
in Year 1 to account for the potential of take of a group of three minke whales.

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 construction of the JRP
in 2015, 1 gray whale was documented approximately 5 km from the platform, and a
group of 6 to 10 unidentified whales, thought to be either gray whales or humpbacks, was
observed approximately 15 km northeast of the platform (Jacobs 2015). 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). None were observed during the 2018 CIPL project in
middle Cook Inlet (Sitkiewicz et al. 2018). In 2020 and 2021, one gray whale was
reported in each season at the POA (61N 2021, 2022a). The documented occasional
presence of gray whales near and north of the project area suggests that gray whale
density may be seasonally higher than the relatively low density suggested by the aerial
surveys. Considering the project area is in middle Cook Inlet where sightings of gray
whales are less common, Furie requested, and NMFS is proposing to authorize, take of
three gray whales in Year 1.
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). Furie requested, and NMFS is proposing to authorize, take of
one group of two fin whales (the lower end of the range of common group sizes) in Year
1.
Killer whales are typically sighted in pods of a few animals to 20 or more
(NOAA, 2022a). During seismic surveys conducted in 2019 by Hilcorp in the lower
Cook Inlet, 21 killer whales were observed, either as single individuals or in groups

ranging in size from 2 to 5 individuals (Fairweather, 2020). Furie requested 10 takes by
Level B harassment in Year 1 to account for 2 groups of 5 animals. NMFS concurs and
proposes to authorize 10 takes by Level B harassment of killer whale.
The 2018 MML aerial survey (Shelden and Wade 2019) estimated a median
group size of approximately 11 beluga whales, although group sizes were highly variable
(2 to 147 whales) as was the case in previous survey years (Boyd et al. 2019). Over 3
seasons of monitoring at the POA, 61N reported groups of up to 53 belugas, with a
median group size of 3 and a mean group size of 4.4 (61N 2021, 2022a, 2022b, and
2022c). 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. 2022). The very large groups seen in the Susitna
River Delta are not expected in Trading Bay or offshore areas near the JRP or the towing
route for the Enterprise 151. 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. Few if any takes of beluga whale are anticipated during
impact installation of the conductor piles. Therefore, Furie requested, and NMFS is
proposing to authorize, 11 takes by Level B harassment of beluga whale in Year 1.
Dall's porpoises typically occur in groups averaging between 2 and 12 individuals
(NOAA, 2024b). During seismic surveys conducted in 2019 by Hilcorp in the lower
Cook Inlet, Dall's porpoises were observed 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. NMFS is proposing to

authorize six takes (two groups of three animals) by Level B harassment of Dall’s
porpoise in Year 1.
Shelden et al. (2014) compiled historical sightings of harbor porpoises from lower
to upper Cook Inlet that spanned from a few animals to 92 individuals. The 2018 CIPL
project that occurred just north of the Action Area in Cook Inlet reported 29 sightings of
44 individuals (Sitkiewicz et al. 2018). While the duration of days that the tugs are
towing a jack-up rig will be less than the CIPL project, given the increase in sightings of
harbor porpoise in recent years, the sighting of harbor porpoise during Hilcorp's rig move
in June 2022, and the inability to shut down the tugs, Furie requested, and NMFS is
proposing to authorize, 12 takes by Level B harassment of harbor porpoise. This accounts
for two potential groups of six animals.
Calculated take of Pacific white-sided dolphin was zero because the estimated
density is zero. However, in 2014, during Apache’s seismic survey program, three Pacific
white-sided dolphins were reported (Lomac-MacNair et al. 2014). They are considered
rare in most of Cook Inlet, including in the lower entrance, but their presence was
documented in Iniskin Bay and mid-inlet through passive acoustic recorders in 2019
(Castellote et al. 2020). Furie conservatively requested three takes based on the potential
that a group similar in size to that encountered in 2014 could occur within the Level B
harassment zone during project activities. NMFS concurs, and has conservatively
proposed to authorize three takes of Pacific white-sided dolphin by Level B harassment.
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). Furie requested two takes 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. NMFS concurs, and has conservatively proposed to authorize two
takes of California sea lion by Level B harassment.
Year 2 IHA
Given that Furie intends to conduct the same activities in Year 2 as in Year 1, take
by Level A harassment and Level B harassment proposed for authorization for Year 2 is
the same as that proposed for authorization for Year 1 (table 12).

Table 13-- Take Proposed for Authorization as a Percentage of Stock Abundance
Species

Humpback
whale

Stock

Abunda
nce
(Nbest)

Year 1

Year 2

Total Take (Level Take as a
Total Take (Level Take as a
A and Level B
Percentage of
A and Level B
Percentage of
harassment)
Stock Abundance harassment)
Stock
Abundance
<1

Hawaii (Hawaii
DPS)

11,278

Mexico- North
Pacific (Mexico
DPS)

N/A1

N/A

N/A

Western North
Pacific

1,084

<1

<1

Minke whale

Alaska

N/A2

N/A

N/A

Gray whale

Eastern Pacific

26,960

<1

<1

Fin whale

Northeast Pacific

UND3

N/A

N/A

Killer whale

Eastern North
Pacific Alaska
Resident

1,920

<1

<1

Eastern North
Pacific Gulf of
Alaska, Aleutian
Islands, and
Bering Sea
Transient

Beluga

Cook Inlet

11

3.9

3.9

Dall’s
porpoise

Alaska

UND5

N/A

N/A

Harbor
porpoise

Gulf of Alaska

31,046

<1

<1

Pacific whitesided dolphin

North Pacific

26,880

<1

<1

<1

<1

<1

Harbor seal

Cook Inlet/
Shelikof

28,411

<1

<1

Steller sea
lion

Western U.S.

49,9326

<1

<1

California sea
lion

U.S.

257,606

<1

<1

Abundance estimates are based upon data collected more than 8 years ago and, therefore, current estimates are considered unknown.
Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al (2006) for additional information on
numbers of minke whales in Alaska.
3 The best available abundance estimate for this stock is not considered representative of the entire stock as surveys were limited to a small portion of the
stock's range.
4 On June 15, 2023, NMFS released an updated abundance estimate for endangered Cook Inlet beluga whales in Alaska (Goetz et al. 2023). Data
collected during NOAA Fisheries’ 2022 aerial survey suggest that the whale population is stable or may be increasing slightly. Scientists estimated that the
population size is between 290 and 386, with a median best estimate of 331. In accordance with the MMPA, this population estimate will be incorporated into the
Cook Inlet beluga whale SAR, which will be reviewed by an independent panel of experts, the Alaska Scientific Review Group. After this review, the SAR will
be made available as a draft for public review before being finalized. When the number of instances of takes is compared to this median abundance, the percent
of the stock proposed for authorization is 3.3 percent.
5 The best available abundance estimate is likely an underestimate for the entire stock because it is based upon a survey that covered only a small portion
of the stock's range.
6 Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys.
2

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, NMFS considers two primary factors:
(1) The manner in which, and the degree to which, the successful implementation
of the measure(s) is expected to reduce impacts to marine mammals, marine mammal
species or stocks, and their habitat, 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 and impact on operations.
In addition to the measures described in detail below, Furie will conduct briefings
between conductor pipe installation supervisors, vessel captains and crew, and the marine

mammal monitoring team before the start of all in-water work and when new personnel
join the work to explain responsibilities, communication procedures, marine mammal
monitoring protocol, and operational procedures.
Mitigation for Rig Tugging/Positioning
NMFS anticipates that there is a discountable potential for marine mammals to
incur PTS from the tugging and positioning, as source levels are relatively low, nonimpulsive, 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 reasonable potential for Level A harassment from rig tugging or
positioning. However, Furie 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.
Protected Species Observers
Furie will station PSOs at the highest possible vantage point on either the rig or
on one of the tugs.
Pre-clearance and Post-Activity Monitoring
The tugs towing a rig are not able to shut down while transiting or positioning the
rig. Furie will maneuver the tugs towing the rig such that they maintain a consistent speed
(approximately 4 knots or less[7 km/hr]) 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.
During tugging activities, Furie would implement a clearance zone of 1,500 m
around the rig for all marine mammals other than Cook Inlet beluga whales. This
proposed clearance zone was determined to be appropriate as it is approximately twice as
large as largest Level A harassment zone (table 10) and is a reasonable distance within

which cryptic species (e.g., porpoises, pinnipeds) could be observed. For Cook Inlet
beluga whales, Furie would implement a clearance zone that extends as far as PSOs can
feasibly observe for Cook Inlet beluga whales. Prior to commencing new 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 (i.e., pre-clearance
monitoring). (Note, transitioning from towing to positioning without shutting down
would not be considered commencing a new operational activity.) If no marine mammals
are observed within the relevant clearance zone during this pre-clearance monitoring
period, tugging activities may commence. If a marine mammal(s) is observed within the
relevant clearance zone during the pre-clearance monitoring period, tugging activities
would be delayed, unless the delay interferes with the safety of working conditions.
Operations would not commence until the PSO(s) observe that: (1) the non-Cook Inlet
beluga whale animal(s) is outside of and on a path away from the clearance zone; (2) the
Cook Inlet beluga whale is no longer detected at any range; or (3) for non-ESA-listed
species, 15 minutes have elapsed without observing the marine mammal, or for ESAlisted species, 30 minutes have elapsed without observing the marine mammal. Once the
PSOs have determined one of those conditions are met, operations may commence. PSOs
would also conduct monitoring for marine mammals through 30 minutes post-completion
of any tugging activity each day, and after each stoppage of 30 minutes or greater.
During nighttime hours or low/no-light conditions, night-vision devices (NVDs)
shown to be effective at detecting marine mammals in low-light conditions (e.g., Portable
Visual Search-7 model, or similar) would be provided to PSOs to aid in their monitoring
of marine mammals. Every effort would be made to observe that the relevant clearance
zone is free of marine mammals by using night-vision devices and or the naked eye,
however it may not always be possible to see and clear the entire clearance zones prior to
nighttime transport. Prior to commencing new operational activities during nighttime

hours, or if there is a 30-minute lapse in operational activities in low/no-light conditions,
the PSOs must observe the extent visible while using night vision devices for 30 minutes
(i.e., pre-clearance monitoring). If no marine mammals are observed during this preclearance period, tugging activities may commence. If a marine mammal(s) is observed
within the pre-clearance monitoring period, tugging activities would be delayed, unless
the delay interferes with the safety of working conditions. Operations would not
commence until the PSO(s) observe that: (1) the animal(s) is outside of the observable
area; or (2) for non-ESA-listed species, 15 minutes have elapsed without observing the
marine mammal, or for ESA-listed species, 30 minutes have elapsed without observing
the marine mammal Once the PSOs have determined one of those conditions are met,
operations may commence.
PSOs must scan the waters for at least 30 minutes after tugging and positioning
activities have been completed each day, and after each stoppage of 30 minutes or
greater.
Should a marine mammal be observed during towing or positioning of the rig, the
PSOs will monitor and carefully record any reactions observed until the towing or
positioning has concluded. PSOs will also collect behavioral information on marine
mammals sighted during monitoring efforts.
Nighttime Work
Furie will conduct tug towing operations with the tide, resulting in a low power
output from the tugs towing the rig, unless human safety or equipment integrity is at risk.
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. Furie will only operate the tug
towing activities at night if necessary to accommodate a favorable tide. Prior to
commencing operational activities during nighttime hours or low/no-light conditions,
Furie must implement the pre-clearance measures described above.

Susitna Delta
The Tyonek platform is within the Susitna Delta Exclusion Zone identified in
Hilcorp’s IHAs (87 FR 62364, October 14, 2022). If Hilcorp does conduct work at the
Tyonek platform, it would maintain operatorship and control of the Enterprise 151 until
the tow is underway with lines taut and the Enterprise 151 is under tug power. Once the
tow is underway, Furie representatives will take over operatorship of the Enterprise 151.
Out of concern for potential disturbance to Cook Inlet beluga whales in sensitive
and essential habitat, Furie would maintain a distance of 2.4 km from the mean lower-low
water (MLLW) line of the Susitna River Delta (Beluga River to the Little Susitna River)
between April 15 and November 15. The dates of applicability of this exclusion zone
have been expanded based on new available science, including visual surveys and
acoustic studies, which indicate that substantial numbers of Cook Inlet beluga whales
continue to occur in the Susitna Delta area through at least mid-November (M. Castellote,
pers. comm., T. McGuire, pers. comm.). Of note, Furie does not expect to operate in this
area, but if it does, this measure would apply.
Mitigation for Conductor Pile Installation
NMFS proposes that Furie must implement the following measures for impact
driving of conductor piles.
Shutdown Zones
The purpose of a shutdown zone is generally to define an area within which
shutdown of the activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). Construction supervisors and crews,
PSOs, and relevant Furie staff must avoid direct physical interaction with marine
mammals during construction activity. If a marine mammal comes within 10 m of such
activity, operations must cease and vessels must reduce speed to the minimum level
required to maintain steerage and safe working conditions, as necessary to avoid direct

physical interaction. Further, Furie must implement shutdown zones as described in table
14. Furie states that if a shutdown or delay occurs, impact installation of the conductor
pipe will not commence or resume until the animal has voluntarily left and been visually
confirmed to be 100 m beyond the shutdown zone and on a trajectory away from the
zone, or 30 minutes have passed without subsequent detections. If Cook Inlet beluga
whales are observed within or approaching the Level B harassment zone for conductor
pipe installation, impact installation of the conductor pipe will be delayed or halted until
the beluga(s) have voluntarily left and been visually confirmed to be 100 m beyond the
Level B harassment zone and on a trajectory away from the zone, or 30 minutes have
passed without subsequent detections.
Table 14-- Shutdown Zones for Conductor Pipe Pile Driving
Hearing Group

Shutdown Zone (m)

Low-frequency Cetaceans

2,000

Mid-frequency Cetaceans

High-frequency Cetaceans

Phocids

Otariids

Protected Species Observers
Furie will establish a monitoring location on the JRP at the highest possible
vantage point to monitor to the maximum extent possible in all directions. Monitoring is
described in more detail in the Proposed Monitoring and Reporting section, below.
Pre- and Post- Activity Monitoring
Monitoring must take place from 30 minutes prior to initiation of pile driving
activity (i.e., pre-start clearance monitoring) through 30 minutes post-completion of pile
driving activity. Pre-start clearance monitoring must be conducted during periods of
visibility sufficient for the lead PSO to determine that the shutdown zones indicated in

table 14 are clear of marine mammals. Pile driving may commence following 30 minutes
of observation when the determination is made that the shutdown zones are clear of
marine mammals. If a marine mammal is observed entering or within the shutdown
zones, pile driving activity must be delayed or halted. If pile driving is delayed or halted
due to the presence of a marine mammal, the activity may not commence or resume until
either the animal has voluntarily exited and been visually confirmed beyond the
shutdown zone for 15 minutes (for non-ESA-listed species) or 30 minutes (for ESA-listed
species) have passed without re-detection of the animal. With the exception of Cook Inlet
beluga whales, if a marine mammal for which take by Level B harassment is authorized
is present in the Level B harassment zone but beyond the relevant shutdown zone,
activities may begin and Level B harassment take would be recorded.
Monitoring for Level A and Level B harassment
PSOs would monitor the shutdown zones and beyond to the extent that PSOs can
see. Monitoring beyond the shutdown zones enables observers to be aware of and
communicate the presence of marine mammals in the project areas outside the shutdown
zones and thus prepare for a potential cessation of activity should the animal enter the
shutdown zone.
Soft Start
Soft-start procedures are used to provide additional protection to marine mammals
by providing warning and/or giving marine mammals a chance to leave the area prior to
the hammer operating at full capacity. For impact pile driving, soft start requires
contractors to provide an initial set of three strikes at reduced energy, followed by a 30second waiting period, then two subsequent reduced-energy strike sets. A soft start must
be implemented at the start of each day's impact pile driving and at any time following
cessation of impact pile driving for a period of 30 minutes or longer.
Mitigation for Helicopter Activities

Helicopters must transit at an altitude of 1,500 ft (457 m) or higher, to the extent
practicable, while adhering to Federal Aviation Administration flight rules (e.g.,
avoidance of cloud ceiling, etc.), excluding takeoffs and landing. If flights must occur at
altitudes less than 1,500 ft due to environmental conditions, aircraft must make course
adjustments, as needed, to maintain at least a 1,500- foot separation from all observed
marine mammals. Helicopters must not hover or circle above marine mammals. A
minimum transit altitude is expected to reduce the potential for disturbance to marine
mammals from transiting aircraft.
Based on our evaluation of Furie’s proposed measures, as well as other measures
considered by NMFS (i.e., the extended clearance zone for beluga whales), 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 while conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the required
monitoring.
Monitoring and reporting requirements prescribed by NMFS should contribute to
improved understanding of one or more of the following:

●

Occurrence of marine mammal species or stocks in the area in which take

is anticipated (e.g., presence, abundance, distribution, density);
●

Nature, scope, or context of likely marine mammal exposure to potential

stressors/impacts (individual or cumulative, acute or chronic), through better
understanding of: (1) action or environment (e.g., source characterization, propagation,
ambient noise); (2) affected species (e.g., life history, dive patterns); (3) co-occurrence of
marine mammal species with the activity; or (4) biological or behavioral context of
exposure (e.g., age, calving or feeding areas);
●

Individual marine mammal responses (behavioral or physiological) to

acoustic stressors (acute, chronic, or cumulative), other stressors, or cumulative impacts
from multiple stressors;
●

How anticipated responses to stressors impact either: (1) long-term fitness

and survival of individual marine mammals; or (2) populations, species, or stocks;
●

Effects on marine mammal habitat (e.g., marine mammal prey species,

acoustic habitat, or other important physical components of marine mammal habitat); and
●

Mitigation and monitoring effectiveness.

Monitoring
Furie would abide by all monitoring and reporting measures contained within the
IHA, if issued, and their Marine Mammal Monitoring and Mitigation Plan (see Appendix
B of Furie’s application). 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 rig is attached to the tugs for the duration of the project. PSOs will be
stationed aboard a tug or the rig during tug towing and positioning and may use a
combination of equipment to perform marine mammal observations and to verify the

required monitoring distance from the project site, including 7 by 50 binoculars and
NMFS approved NVDs for low light and nighttime operations. A minimum of two
NMFS-approved PSOs will be stationed on the JRP at the highest possible vantage point
to monitor to the maximum extent possible in all directions during pile driving. PSOs
would be independent of the activity contractor (for example, employed by a
subcontractor) and have no other assigned tasks during monitoring periods. At least one
PSO would have prior experience performing the duties of a PSO during an activity
pursuant to a NMFS-issued Incidental Take Authorization or Letter of Concurrence.
Other PSOs may substitute other relevant experience (including relevant Alaska Native
traditional knowledge), education (degree in biological science or related field), or
training for prior experience performing the duties of a PSO. Where a team of three or
more PSOs is required, a lead observer or monitoring coordinator must be designated.
The lead observer must have prior experience performing the duties of a PSO during an
activity pursuant to a NMFS-issued incidental take authorization.
PSOs would also have the following additional qualifications:
●

PSOs must be able to conduct field observations and collect data

according to assigned protocols;
●

PSOs must have experience or training in the field identification of marine

mammals, including the identification of behaviors;
●

PSOs must have sufficient training, orientation, or experience with the

tugging operation to provide for personal safety during observations;
●

PSOs must have sufficient writing skills to record required information

including but not limited to the number and species of marine mammals observed; dates
and times when in-water tugging activities were conducted; dates, times, and reason for
implementation of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and

●

PSOs must have the 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.
Reporting
Furie would submit interim monthly reports for all months in which tugs towing,
holding, or positioning the rig occurs. Monthly reports would include a summary of
marine mammal species and behavioral observations, delays, and tugging activities
completed. They also must include an assessment of the amount of tugging remaining to
be completed, in addition to the number of Cook Inlet beluga whales observed within
estimated harassment zones to date.
A draft marine mammal monitoring report would be submitted to NMFS within
90 days after the completion of the tug towing 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 in an electronic format.
Specifically, the report must include the following information:
●

Date and time that monitored activity begins or ends;

●

Activities occurring during each observation period, including (a) the type

of activity, (b) the total duration of each type of activity, (c) the number of attempts
required for positioning, (d) when nighttime operations were required (e) whether towing
against the tide was required, (f) the number and type of piles that were driven and the
method (e.g., impact, vibratory, down-the-hole), and (g) total number of strikes for each
pile.
●

PSO locations during marine mammal monitoring;

●

Environmental conditions during monitoring periods (at the beginning and

end of the PSO shift and whenever conditions change significantly), including Beaufort

sea state, tidal state, and any other relevant weather conditions, including cloud cover,
fog, sun glare, overall visibility to the horizon, and estimated observable distance;
●

Upon observation of a marine mammal, (a) name of PSO who sighted the

animal(s) and PSO location and activity at time of sighting, (b) time of sighting, (c)
identification of the animal(s) (e.g., genus/species, lowest possible taxonomic level, or
unidentified), PSO confidence in identification, and the composition of the group if there
is a mix of species, (d) distance and location of each observed marine mammal relative to
the tugs or pile being driven for each sighting, (e) estimated number of animals
(min/max/best estimate), (f) estimated number of animals by cohort (adults, juveniles,
neonates, group composition, etc.), (g) animal’s closest point of approach and estimated
time spent within the harassment zone, (h) description of any marine mammal behavioral
observations (e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the activity (e.g., no
response or changes in behavioral state such as ceasing feeding, changing direction,
flushing, or breaching);
●

Number of marine mammals detected within the harassment zones, by

species; and
●

Detailed information about implementation of any mitigation (e.g.,

shutdowns and delays), a description of specific actions that ensued, and resulting
changes in behavior of the animal(s), if any.
If no comments are received from NMFS within 30 days, the draft summary
report will constitute the final report. If NMFS submits comments, Furie will submit a
final summary report addressing NMFS comments within 30 days after receipt of
comments.
In the event that personnel involved in Furie’s activities discover an injured or
dead marine mammal, Furie must report the incident to the Office of Protected Resources

(OPR), NMFS (PR.ITP.MonitoringReports@noaa.gov and ITP.davis@noaa.gov) and to
the Alaska regional stranding network as soon as feasible. If the death or injury was
clearly caused by the specified activity, Furie must immediately cease the activities until
NMFS OPR is able to review the circumstances of the incident and determine what, if
any, additional measures are appropriate to ensure compliance with the IHAs. The Holder
must not resume their activities until notified by NMFS.
The report must include the following information:
(i)

Time, date, and location (latitude/longitude) of the first discovery (and

updated location information if known and applicable);
(ii)

Species identification (if known) or description of the animal(s) involved;

(iii)

Condition of the animal(s) (including carcass condition if the animal is

(iv)

Observed behaviors of the animal(s), if alive;

(v)

If available, photographs or video footage of the animal(s); and

(vi)

General circumstances under which the animal was discovered.

dead);

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 majority of our analysis applies to all the species listed in
table 13, except for Cook Inlet beluga whale and harbor seal, given that many of the
anticipated effects of this project on different marine mammal stocks are expected to be
relatively similar in nature. For Cook Inlet beluga whales and harbor seals, there are
meaningful differences in anticipated individual responses to activities, impact of
expected take on the population, or impacts on habitat; therefore, we provide a separate
independent detailed analysis for Cook Inlet beluga whales and harbor seals following the
analysis for other species for which we propose take authorization.
NMFS has identified several key factors which may be employed to assess the
level of analysis necessary to conclude whether potential impacts associated with a
specified activity should be considered negligible. These include (but are not limited to)
the type and magnitude of taking, the amount and importance of the available habitat for
the species or stock that is affected, the duration of the anticipated effect on the
individuals, and the status of the species or stock. The potential effects of the specified
activity on humpback whales, minke whales, gray whales, fin whales, killer whales,
Dall’s porpoises, harbor porpoises, Pacific white-sided dolphins, Steller sea lions, and
California sea lions are discussed below. These factors also apply to Cook Inlet beluga

whales and harbor seals; however, additional analysis for Cook Inlet beluga whales and
harbor seals is provided in a separate subsection below.
Furie’s tugging activities associated with this project, as outlined previously, have
the potential to harass marine mammals. Specifically, the specified activities may result
in take, in the form of Level B harassment, from underwater sounds generated by tugs
towing, holding, and positioning a rig. Potential takes could occur if marine mammals are
present in zones ensonified above the thresholds for Level B harassment, identified
above, while activities are underway.
Furie's planned activities and associated impacts would occur within a limited
area of the affected species’ or stocks' ranges over a total of 4 days each year for tugging,
and 2 days for pile driving. The intensity and duration of take by Level B harassment
would be minimized through use of mitigation measures described herein. Further the
amount of take proposed to be authorized is small when compared to stock abundance
(table 13). In addition, NMFS does not anticipate that serious injury or mortality would
occur as a result of Furie’s planned activity given the nature of the activity, even in the
absence of required mitigation.
Exposures to elevated sound levels produced during tugging and pile driving
activities may cause behavioral disturbance of some individuals within the vicinity of the
sound source. Behavioral responses of marine mammals to Furie’s tugging activities are
expected to be mild, short term, and temporary. Effects on individuals that are taken by
Level B harassment, as enumerated in the Estimated Take section, on the basis of
reports in the literature as well as monitoring from other similar activities conducted by
Furie (Horsley and Larson, 2023), would likely be limited to behavioral response such as
increased swimming speeds, changing in directions of travel and diving and surfacing
behaviors, increased respiration rates, or interrupted foraging (if such activity were
occurring) (Ridgway et al. 1997; Nowacek et al. 2007; Thorson and Reyff, 2006; Kendall

and Cornick 2015; Goldbogen et al. 2013b; Blair et al. 2016; Wisniewska et al. 2018;
Piwetz et al. 2021). Marine mammals within the Level B harassment zones may not
present any visual cues they are disturbed by activities, or they may become alert, avoid
the area, leave the area, or have other mild responses that are not observable such as
increased stress levels (e.g., Rolland et al. 2012; Lusseau, 2005; Bejder et al. 2006; Rako
et al. 2013; Pirotta et al. 2015b; Pérez-Jorge et al. 2016). They may also exhibit increased
vocalization rates (e.g., Dahlheim 1987; Dahlheim and Castellote 2016), louder
vocalizations (e.g., Frankel and Gabriele 2017; Fournet et al. 2018), alterations in the
spectral features of vocalizations (e.g., Castellote et al. 2012), or a cessation of
communication signals (e.g., Tsujii et al. 2018). However, as described in the Potential
Effects of Specified Activities on Marine Mammals and Their Habitat section,
marine mammals observed near Furie’s tugging activities have shown little to no
observable reactions to tugging activities (Horsley and Larson 2023).
Tugs pulling, holding, and positioning a rig are slow-moving as compared to
typical recreational and commercial vessel traffic. Assuming an animal was stationary,
exposure to sound above the Level B harassment threshold from the moving tug
configuration (which comprises most of the tug activity being considered) would be on
the order of minutes in any particular location. The slow, predictable, and generally
straight path of this activity is expected to further lower the likelihood of more than lowlevel responses to the sound. Also, this slow transit along a predictable path is planned in
an area of routine vessel traffic where many large vessels move in slow straight-line
paths, and some individuals are expected to be habituated to these sorts of sounds. While
it is possible that animals may swim around the project area, avoiding closer approaches
to the boats, we do not expect them to abandon any intended path. Further, most animals
present in the region would likely be transiting through the area; therefore, any potential
exposure is expected to be brief. Based on the characteristics of the sound source and the

other activities regularly encountered in the area, it is unlikely Furie’s planned tugging
activities would be of a duration or intensity expected to result in impacts on reproduction
or survival.
Effects on individuals that are taken by Level B harassment during pile driving,
on the basis of reports in the literature as well as monitoring from other similar activities,
would likely be limited to reactions such as increased swimming speeds, increased
surfacing time, or interrupted foraging (if such activity were occurring; e.g., Thorson and
Reyff 2006; HDR, Inc. 2012; Lerma 2014; ABR 2016). Most likely, individuals would
simply move away from the sound source and be temporarily displaced from the areas of
pile driving and removal. If sound produced by project activities is sufficiently
disturbing, animals are likely to simply avoid the area while the activity is occurring,
particularly as the project is expected to occur over a maximum of just 2 days of in-water
pile driving during each year.
Most of the species present in the region would only be present temporarily based
on seasonal patterns or during transit between other habitats. These temporarily present
species would be exposed to even smaller periods of noise-generating activity, further
decreasing the impacts. Most likely, individual animals would simply move away from
the sound source and be temporarily displaced from the area. Takes may also occur
during important feeding times. The project area though represents a small portion of
available foraging habitat and impacts on marine mammal feeding for all species should
be minimal.
We anticipate that any potential reactions and behavioral changes are expected to
subside quickly when the exposures cease and, therefore, we do not expect long-term
adverse consequences from Furie’s proposed activities for individuals of any species
other than harbor seal (for which take by Level A harassment is proposed for
authorization, discussed further below). The intensity of Level B harassment events

would be minimized through use of mitigation measures described herein. Furie would
use PSOs to monitor for marine mammals before commencing any tugging or
construction activities, which would minimize the potential for marine mammals to be
present within Level B harassment zones when tugs are under load or within the
shutdown zones at the commencement of construction. Further, given the absence of any
major rookeries, haulouts, or areas of known biological significance for marine mammals
(e.g., foraging hot spots) within the estimated harassment zones (other than critical
habitat and a BIA for Cook Inlet beluga whales as described below), we preliminarily
conclude that any takes by Level B harassment would have an inconsequential short-term
effect on individuals and would not result in population-level impacts.
Theoretically, repeated, sequential exposure to elevated noise from tugging
activities over a long duration could result in more severe impacts to individuals that
could affect a population (via sustained or repeated disruption of important behaviors
such as feeding, resting, traveling, and socializing; Southall et al. 2007). Alternatively,
marine mammals exposed to repetitious sounds may become habituated, desensitized, or
tolerant after initial exposure to these sounds (reviewed by Richardson et al. 1995;
Southall et al. 2007). Cook Inlet is a regional hub of marine transportation, and is used by
various classes of vessels, including containerships, bulk cargo freighters, tankers,
commercial and sport-fishing vessels, and recreational vessels. Off-shore vessels, tug
vessels, and tour boats represent 86 percent of the total operating days for vessels in Cook
Inlet (BOEM 2016). Given that marine mammals still frequent and use Cook Inlet despite
being exposed to anthropogenic sounds such as those produced by tug boats and other
vessels across many years, population level impacts resulting from the additional noise
produced by Furie’s tugging activities are not anticipated.
Take by Level A harassment of harbor seals is proposed for authorization to
account for the potential that an animal could enter and remain within the area between a

Level A harassment zone and the shutdown zone during conductor pile installation for a
duration long enough to be taken by Level A harassment. Any take by Level A
harassment is expected to arise from, at most, a small degree of PTS because animals
would need to be exposed to higher levels and/or longer duration than are expected to
occur here in order to incur any more than a small degree of PTS. Additionally, some
subset of the individuals that are behaviorally harassed could also simultaneously incur
some small degree of TTS for a short duration of time. Because of the small degree
anticipated, though, any PTS or TTS potentially incurred here is not expected to
adversely impact individual fitness, let alone annual rates of recruitment or survival.
Furie’s tugging activities are not expected to have significant adverse effects on
any marine mammal habitat as no temporary or physical impacts to habitat are
anticipated to result from the specified activities. During both tugging and construction,
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 the proposed activity is small relative to the overall distribution of
the animals in the area and their use of the area. Additionally, the habitat within the
estimated acoustic footprint is not known to be heavily used by marine mammals.
Impacts to marine mammal prey species are expected to be minor and temporary,
having, at most, short-term effects on foraging success of individual marine mammals,
and likely no effect on the populations of marine mammals as a whole. Overall, as
described above, the area anticipated to be impacted by Furie’s tugging and construction
activities is very small compared to the available surrounding habitat, and does not
include habitat of particular importance. The most likely impact to prey would be
temporary behavioral avoidance of the immediate area. During tugging and construction
activities, it is expected that some fish would temporarily leave the area of disturbance
(e.g., Nakken 1992; Olsen 1979; Ona and Godo 1990; Ona and Toresen, 1988), thus

impacting marine mammals' foraging opportunities in a limited portion of their foraging
range. But, because of the relatively small area of the habitat that may be affected, and
lack of any foraging habitat of particular importance, the impacts to marine mammal
habitat are not expected to cause significant or long-term negative consequences.
Finally, Furie will minimize exposure of marine mammals to elevated noise levels
by implementing mitigation measures for tugging and construction activities. For
tugging, Furie would delay tugging activities if marine mammals are observed during the
pre-clearance monitoring period. Furie would also implement vessel maneuvering
measures to reduce the likelihood of disturbing marine mammals during any periods
when marine mammals may be present near the vessels. Lastly, Furie would also reduce
the impact of their activity by conducting tugging operations with favorable tides
whenever feasible. For construction, Furie would also delay the start of pile driving
activities if marine mammals are observed during the pre-clearance monitoring period
and would implement hearing group-specific shutdown zones during the activities. Furie
would also implement soft-start procedures to provide warning and/or give marine
mammals a chance to leave the area prior to the hammer operating at full capacity.
In summary and as described above, the following factors (with additional
analyses for Cook Inlet beluga whales included below) primarily support our preliminary
determination that the impacts resulting from the activities described for both of these
proposed IHAs are not expected to adversely affect the species or stocks through effects
on annual rates of recruitment or survival:
●

No serious injury or mortality is anticipated or proposed for authorization;

●

Take by Level A harassment is not anticipated or proposed for

authorization for any species except harbor seal;

●

Exposure to sounds above harassment thresholds would likely be brief

given the short duration of the specified activity and the transiting behavior of marine
mammals in the action area;
●

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;
●

Take would not occur in places and/or times where take would be more

likely to accrue to impacts on reproduction or survival, such as within ESA-designated or
proposed critical habitat, BIAs (other than for Cook Inlet beluga whales as described
below), or other habitats critical to recruitment or survival (e.g., rookery);
●

The project area represents a very small portion of the available foraging

area for all potentially impacted marine mammal species;
●

Take would only occur within middle Cook Inlet and Trading Bay – a

limited area of any given species or stock’s home range;
●

Monitoring reports from previous tugging activities in Cook Inlet have

documented little to no observable effect on individuals of the same species and stocks
impacted by the specified activities;
●

The required mitigation measures (i.e., pre-clearance monitoring, vessel

maneuver) are expected to be effective in reducing the effects of the specified activity by
minimizing the numbers of marine mammals exposed to sound and the intensity of the
exposures; and
●

The intensity of anticipated takes by Level B harassment is low for all

species and stocks, consisting of, at worst, temporary modifications in behavior, and
would not be of a duration or intensity expected to result in impacts on reproduction or
survival of individuals.
Cook Inlet Beluga Whale

For Cook Inlet beluga whales, we further discuss our negligible impact analysis
in addition to the assessment above for all species in the context of potential impacts to
this endangered stock based on our evaluation of the take proposed to be authorized
(table 13).
All tugging activities would be done in a manner implementing best management
practices to preserve water quality, and no work would occur around creek mouths or
river systems leading to prey abundance reductions. In addition, no physical structures
would restrict passage; however, impacts to the acoustic habitat are relevant and
discussed here.While the specified activity would occur within Cook Inlet beluga whale
Critical Habitat Area 2 (and potentially Area 1, depending on the origin of the tug tow),
and recognizing that Cook Inlet beluga whales have been identified as a small and
resident population, monitoring data from Hilcorp’s activities suggest that tugging
activities do not discourage Cook Inlet beluga whales from transiting throughout Cook
Inlet and between critical habitat areas and that the whales do not abandon critical habitat
areas (Horsley and Larson, 2023). In addition, large numbers of Cook Inlet beluga whales
have continued to use Cook Inlet and pass through the area, likely traveling to critical
foraging grounds found in upper Cook Inlet, while noise-producing anthropogenic
activities, including vessel use, have taken place during the past two decades (e.g.,
Shelden et al. 2013, 2015, 2017, 2022; Shelden and Wade 2019; Geotz et al. 2023).
These findings are not surprising as food is a strong motivation for marine mammals. As
described in Forney et al. (2017), animals typically favor particular areas because of their
importance for survival (e.g., feeding or breeding), and leaving may have significant
costs to fitness (reduced foraging success, increased predation risk, increased exposure to
other anthropogenic threats). Consequently, animals may be highly motivated to maintain
foraging behavior in historical foraging areas despite negative impacts (e.g., Rolland et
al. 2012).

Generation of sound may result in avoidance behaviors that would be limited in
time and space relative to the larger availability of important habitat areas in Cook Inlet;
however, the area ensonified by sound from the specified activity is anticipated to be
small compared to the overall available critical habitat for Cook Inlet beluga whales to
feed and travel. Therefore, the specified activity would not create a barrier to movement
through or within important areas. We anticipate that disturbance to Cook Inlet beluga
whales would manifest in the same manner as other marine mammals described above
(i.e., increased swimming speeds, changes in the direction of travel and dive behaviors,
increased respiration rates, decreased foraging (if such activity were occurring), or
alterations to communication signals). We do not believe exposure to elevated noise
levels during transit past tugging or construction activities would have adverse effects on
individuals' fitness for reproduction or survival.
Although data demonstrate that Cook Inlet beluga whales are not abandoning the
planned project area during anthropogenic activities, results of an expert elicitation (EE)
at a 2016 workshop, which predicted the impacts of noise on Cook Inlet beluga whale
survival and reproduction given lost foraging opportunities, helped to inform our
assessment of impacts on this stock. The 2016 EE workshop used conceptual models of
an interim population consequences of disturbance (PCoD) for marine mammals (NRC,
2005; New et al. 2014; Tollit et al. 2016) to help in understanding how noise-related
stressors might affect vital rates (survival, birth rate and growth) for Cook Inlet beluga
whale (King et al. 2015). NMFS (2016b) suggests that the main direct effects of noise on
Cook Inlet beluga whales are likely to be through masking of vocalizations used for
communication and prey location and habitat degradation. The 2016 workshop on Cook
Inlet beluga whales was specifically designed to provide regulators with a tool to help
understand whether chronic and acute anthropogenic noise from various sources and
projects are likely to be limiting recovery of the Cook Inlet beluga whale population. The

full report can be found at https://www.smruconsulting.com/publications/ with a
summary of the expert elicitation portion of the workshop below.
For each of the noise effect mechanisms chosen for EE, the experts provided a set
of parameters and values that determined the forms of a relationship between the number
of days of disturbance a female Cook Inlet beluga whale experiences in a particular
period and the effect of that disturbance on her energy reserves. Examples included the
number of days of disturbance during the period of April, May, and June that would be
predicted to reduce the energy reserves of a pregnant Cook Inlet beluga whale to such a
level that she is certain to terminate the pregnancy or abandon the calf soon after birth,
the number of days of disturbance in the period of April-September required to reduce the
energy reserves of a lactating Cook Inlet beluga whale to a level where she is certain to
abandon her calf, and the number of days of disturbance where a female fails to gain
sufficient energy by the end of summer to maintain herself and her calf during the
subsequent winter. Overall, median values ranged from 16 to 69 days of disturbance
depending on the question. However, for this elicitation, a “day of disturbance” was
defined as any day on which an animal loses the ability to forage for at least one tidal
cycle (i.e., it forgoes 50–100 percent of its energy intake on that day). The day of
disturbance considered in the context of the report is notably more severe than the Level
B harassment expected to result from these activities, which as described is expected to
be comprised predominantly of temporary modifications in the behavior of individual
Cook Inlet beluga whales (e.g., faster swim speeds, longer dives, decreased sighting
durations, alterations in communication). Also, NMFS proposes to authorize 11 instances
of take by Level B harassment during each year, with the instances representing
disturbance events within a day—this means that either 11 different individual Cook Inlet
beluga whales are disturbed on no more than 1 day each, or some lesser number of
individuals may be disturbed on more than 1 day, but with the total number of takes not

exceeding 11. Given the overall anticipated take, and the short duration of the specified
activities, it is unlikely that any one Cook Inlet beluga whale will be disturbed on more
than a couple of days. Further, Furie has proposed mitigation measures specific to Cook
Inlet beluga whales whereby they would not begin tugging activities should a Cook Inlet
beluga whale be observed at any distance. While take by Level B harassment (behavioral
disturbance) would be authorized, this measure, along with other mitigation measures
described herein, would limit the severity of the effects of that Level B harassment to
behavioral changes such as increased swim speeds, changes in diving and surfacing
behaviors, and alterations to communication signals, not the loss of foraging capabilities.
Finally, take by mortality, serious injury, or Level A harassment of Cook Inlet beluga
whales is not anticipated or proposed to be authorized.
In summary and as described above, the additional following factors primarily
support our preliminary determination that the impacts resulting from this activity are not
expected to adversely affect the Cook Inlet beluga whale through effects on annual rates
of recruitment or survival:
●

The area of exposure would be limited to habitat primarily used for

transiting, and not areas known to be of particular importance for feeding or
reproduction;
●

The activities are not expected to result in Cook Inlet beluga whales

abandoning critical habitat nor are they expected to restrict passage of Cook Inlet beluga
whales within or between critical habitat areas; and
●

Any disturbance to Cook Inlet beluga whales is expected to be limited to

temporary modifications in behavior, and would not be of a duration or intensity expected
to result in impacts on reproduction or survival.
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 proposed for Year 1 of activity will
have a negligible impact on all affected marine mammal species or stocks. Separately,
NMFS preliminary finds that the total marine mammal take proposed for Year 2 of
activity will have a negligible impact on all affected marine mammal species or stocks.
Small Numbers
As noted previously, take of only small numbers of marine mammals may be
authorized under sections 101(a)(5)(A) and (D) of the MMPA for specified activities
other than military readiness activities. The MMPA does not define small numbers and
so, in practice, where estimated numbers are available, NMFS compares the number of
individuals taken to the most appropriate estimation of abundance of the relevant species
or stock in our determination of whether an authorization is limited to small numbers of
marine mammals. When the predicted number of individuals to be taken is fewer than
one-third of the species or stock abundance, the take is considered to be of small
numbers. Additionally, other qualitative factors may be considered in the analysis, such
as the temporal or spatial scale of the activities.
Table 13 provides the quantitative analysis informing our small numbers
determinations for the Year 1 and Year 2 IHAs. For all stocks whose abundance estimate
is known, the amount of taking is less than one-third of the best available population
abundance estimate (in fact it is less than 1 percent for all stocks, except for Cook Inlet
beluga whales whose proposed take is 3.9 percent of the stock; table 13). The number of
animals proposed for authorization to be taken from these stocks therefore, would be
considered small relative to the relevant stock's abundances even if each estimated take
occurred to a new individual.
Abundance estimates for the Mexico-North Pacific stock of humpback whales are
based upon data collected more than 8 years ago and, therefore, current estimates are

considered unknown (Young et al. 2023). The most recent minimum population
estimates (NMIN) for this population include an estimate of 2,241 individuals between
2003 and 2006 (Martinez-Aguilar 2011) and 766 individuals between 2004 and 2006
(Wade 2021). NMFS' Guidelines for Assessing Marine Mammal Stocks suggest that the
NMIN estimate of the stock should be adjusted to account for potential abundance changes
that may have occurred since the last survey and provide reasonable assurance that the
stock size is at least as large as the estimate (NMFS 2023b). The abundance trend for this
stock is unclear; therefore, there is no basis for adjusting these estimates (Young et al.
2023). Assuming the population has been stable, and that the 3 takes of humpback whale
proposed for authorization would all be of the Mexico-North Pacific stock, this represents
small numbers of this stock (less than 1 percent of the stock assuming a NMIN of 2,241
individuals and <1 percent of the stock assuming an NMIN of 766 individuals).
A lack of an accepted stock abundance value for the Alaska stock of minke whale
did not allow for the calculation of an expected percentage of the population that would
be affected during each Year. The most relevant estimate of partial stock abundance is
1,233 minke whales in coastal waters of the Alaska Peninsula and Aleutian Islands
(Zerbini et al. 2006). Given three takes by Level B harassment proposed for authorization
for the stock during Year 1 and Year 2, comparison to the best estimate of stock
abundance shows, at most, less than 1 percent of the stock would be expected to be
impacted.
There is no stock-wide abundance estimate for Northeast Pacific fin whales.
However, Young et al. (2022) estimate the minimum stock size for the areas surveyed is
2,554. Given 2 takes by Level B harassment proposed for authorization for the stock
during Year 1 and Year 2, comparison to the minimum population estimate shows, at
most, less than 1 percent of the stock would be expected to be impacted.

The Alaska stock of Dall's porpoise has no official NMFS abundance estimate for
this area, as the most recent estimate is greater than 8 years old. As described in the 2022
Alaska SAR (Young et al. 2023) the minimum population estimate is assumed to
correspond to the point estimate of the 2015 vessel-based abundance computed by Rone
et al. (2017) in the Gulf of Alaska (N = 13,110; CV = 0.22). Given 6 takes by Level B
harassment proposed for authorization for the stock during Year 1 and Year 2,
comparison to the minimum population estimate shows, at most, less than 1 percent of
the stock would be expected to be impacted.
Based on the analysis contained herein of the proposed activity (including the
proposed mitigation and monitoring measures) and the anticipated take of marine
mammals, NMFS preliminarily finds that small numbers of marine mammals would be
taken relative to the population size of the affected species or stocks 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 subsistence uses of the affected marine mammal
species or stocks by Alaskan 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.

Subsistence communities identified as project stakeholders near Furie’s middle
Cook Inlet (and potentially Trading Bay, depending on where Furie takes over the rig
from Hilcorp) activities include the Village of Salamatof and the Native Village of
Tyonek. The Alaska Department of Fish and Game 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 assume the subsistence uses are similar to those of nearby
communities such as Kenai. 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 mi) 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.
Furie’s tug towing 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 Furie’s tugging (all, with the exception of returning the rig
to the Rig Tender’s Dock, located in an industrialized area of Nikiski, Alaska), as well as
its pile driving, 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 for harvest.
However, to further minimize any potential effects of their action on subsistence
activities, Furie plans to conduct stakeholder outreach before the planned operations in
2024 and 2025, according to its Stakeholder Engagement Plan. According to Furie, they
contacted Alaska Native Tribes in the Cook Inlet Region by email and phone message.
To date, Furie has not received any responses from the Tribes. Furie states it will expand

the effort to include Cook Inlet Regional Inc. and Chugach Alaska Corporation and will
continue to reach out to the Tribes as the project nears. Furie must coordinate with local
Tribes as described in its Stakeholder Engagement Plan, notify the communities of any
changes in the operation, and take action to avoid or mitigate impacts to subsistence
harvests.
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
Furie’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 Furie’s proposed activities under the Year 2 IHA.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (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 NMFS Alaska
Regional Office (AKRO).
NMFS is proposing to authorize take of fin whale, humpback whale (Mexico
Distinct Population Segment (DPS), beluga whale (Cook Inlet), and Steller sea lion
(Western DPS), which are listed under the ESA. The Permits and Conservation Division
has requested initiation of section 7 consultation with the NMFS AKRO for the issuance
of this IHA. 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
IHAs to Furie for conducting oil and gas activities in Cook Inlet, Alaska from 2024-2026,
provided the previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. Drafts of the proposed IHAs can be found at:
https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marinemammal-protection-act.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and any other
aspect of this notice of proposed IHAs for the proposed oil and gas activities. We also
request comment on the potential renewal of these proposed IHAs as described in the
paragraph below. Please include with your comments any supporting data or literature
citations to help inform decisions on the proposed IHAs or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-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 Activity section of this notice is planned; or (2) the activities as
described in the Description of Proposed Activity section of this notice would not be
completed by the time the IHA expires and a renewal would allow for completion of the
activities beyond that described in the Dates and Duration section of this notice, provided
all of the following conditions are met:
●

A request for renewal is received no later than 60 days prior to the needed

renewal IHA effective date (recognizing that the renewal IHA expiration date cannot
extend beyond one year from expiration of the initial IHA).
●

The request for renewal must include the following:

(1)

An explanation that the activities to be conducted under the requested

renewal IHA are identical to the activities analyzed under the initial IHA, are a subset of
the activities, or 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); and
(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: June 10, 2024.
Angela Somma,
Acting Director, Office of Protected Resources,
National Marine Fisheries Service.

[FR Doc. 2024-13000 Filed: 6/13/2024 8:45 am; Publication Date: 6/14/2024]