[Federal Register Volume 84, Number 148 (Thursday, August 1, 2019)]
[Rules and Regulations]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-16279]
August 1, 2019
Department of the Interior
Fish and Wildlife Service
50 CFR Part 18
Marine Mammals; Incidental Take During Specified Activities: Cook
Inlet, Alaska; Final Rule
Federal Register / Vol. 84 , No. 148 / Thursday, August 1, 2019 /
Rules and Regulations
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 18
[Docket No. FWS-R7-ES-2019-0012; FXES111607MRG01-190-FF07CAMM00]
Marine Mammals; Incidental Take During Specified Activities: Cook
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Final rule.
SUMMARY: We, the U.S. Fish and Wildlife Service, in response to a
request from Hilcorp Alaska, LLC, Harvest Alaska, LLC, and the Alaska
Gasline Development Corporation, finalize regulations authorizing the
nonlethal, incidental take by harassment of small numbers of northern
sea otters in State and Federal waters (Alaska and the Outer
Continental Shelf) within Cook Inlet, Alaska, as well as all adjacent
rivers, estuaries, and coastal lands. Take may result from oil and gas
exploration, development, production, and transportation activities
occurring for a period of 5 years. This rule authorizes take by
harassment only; no lethal take is authorized. We will issue Letters of
Authorization, upon request, for specific proposed activities in
accordance with these regulations. Additionally, the Office of
Management and Budget has approved a revision of the existing
Information Collection control number 1018-0070, for incidental take of
marine mammals in the Beaufort and Chukchi Seas, to include oil and gas
activities in Cook Inlet.
DATES: This rule is effective August 1, 2019, and remains effective
through August 1, 2024.
ADDRESSES: Document availability: You may view this rule, the original
and updated application packages, supporting information, final
environmental assessment and U.S. Fish and Wildlife Service finding of
no significant impact (FONSI), and the list of references cited herein
at http://www.regulations.gov under Docket No. FWS-R7-ES-2019-0012, or
these documents may be requested as described under FOR FURTHER
FOR FURTHER INFORMATION CONTACT: Mr. Christopher Putnam, U.S. Fish and
Wildlife Service, MS 341, 1011 East Tudor Road, Anchorage, Alaska
99503, by email at email@example.com, or by telephone at 1-
800-362-5148. Persons who use a telecommunications device for the deaf
(TDD) may call the Federal Relay Service (FRS) at 1-800-877-8339, 24
hours a day, 7 days a week.
For information on Information Collection control number 1018-0070,
contact the Service Information Collection Clearance Officer, U.S. Fish
and Wildlife Service, MS: BPHC, 5275 Leesburg Pike, Falls Church, VA
22041-3803 (mail); 703-358-2503 (telephone), or firstname.lastname@example.org
(email). Please include ``1018-0070'' in the subject line of your email
In accordance with 5 U.S.C. 553(d)(3), we find that we have good
cause to make this rule effective less than 30 days after publication.
Immediate promulgation of the rule will ensure that the applicant will
implement mitigation measures and monitoring programs in the geographic
region that reduce the risk of any lethal and nonlethal effects to sea
otters by their activities.
Section 101(a)(5)(A) of the Marine Mammal Protection Act of 1972
(16 U.S.C. 1361(a)(5)(A)) (MMPA), gives the Secretary of the Interior
(Secretary) the authority to allow the incidental, but not intentional,
taking of small numbers of marine mammals in response to requests by
U.S. citizens engaged in a specified activity in a specified region.
The Secretary has delegated authority for implementation of the MMPA to
the U.S. Fish and Wildlife Service (Service). According to the MMPA,
the Service shall allow this incidental taking for a period of up to 5
years if we make findings that such taking: (1) Will affect only small
numbers of individuals of these species or stocks; (2) will have no
more than a negligible impact on these species or stocks; (3) will not
have an unmitigable adverse impact on the availability of these species
or stocks for taking for subsistence use by Alaska Natives; and (4) we
issue an incidental take regulation (ITR) setting forth: (a) The
permissible methods of taking, (b) the means of effecting the least
practicable adverse impact on the species, their habitat, and the
availability of the species for subsistence uses, and (c) the
requirements for monitoring and reporting. If final regulations
allowing such incidental taking are issued, we may then subsequently
issue a letter of authorization (LOA), upon request, to authorize
incidental take during the specified activities.
The term ``take,'' as defined by the MMPA, means to harass, hunt,
capture, or kill, or to attempt to harass, hunt, capture, or kill any
marine mammal (16 U.S.C. 1362(13)). Harassment, as defined by the MMPA
for non-military readiness activities, means any act of pursuit,
torment, or annoyance that (i) has the potential to injure a marine
mammal or marine mammal stock in the wild (the MMPA calls this ``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 (the MMPA calls this ``Level B
The terms ``negligible impact,'' ``small numbers,'' ``unmitigable
adverse impact,'' and ``U.S. citizens,'' among others, are defined in
title 50 of the Code of Federal Regulations at 50 CFR 18.27, the
Service's regulations governing take of small numbers of marine mammals
incidental to specified activities. ``Negligible impact'' is defined 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. ``Small numbers'' is defined as a portion of a
marine mammal species or stock whose taking would have a negligible
impact on that species or stock. However, we do not rely on that
definition here, as it conflates the terms ``small numbers'' and
``negligible impact,'' which we recognize as two separate and distinct
requirements. Instead, in our small numbers determination, we evaluate
whether the number of marine mammals likely to be taken is small
relative to the size of the overall stock.
``Unmitigable adverse impact'' is defined 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. The term ``least practicable adverse
impact'' is not defined in the MMPA or its enacting regulations. We
ensure the least practicable adverse impact by requiring mitigation
measures that are effective in reducing the impacts of the
proposed activities, but are not so restrictive as to make conducting
the activities unduly burdensome or impossible to undertake and
Implementation of the ITR will require information collection
activities. The Office of Management and Budget has approved a revision
of the existing Information Collection control number 1018-0070, for
incidental take of marine mammals in the Beaufort and Chukchi Seas, to
include oil and gas activities in Cook Inlet.
Summary of Request
On May 3, 2018, Hilcorp Alaska, LLC (Hilcorp), Harvest Alaska, LLC
(Harvest), and the Alaska Gasline Development Corporation (AGDC),
hereinafter referred to as the ``applicant,'' petitioned the Service to
promulgate regulations pursuant to section 101(a)(5)(A) of the MMPA for
the nonlethal, unintentional taking of small numbers of northern sea
otters (Enhydra lutris kenyoni; hereafter ``sea otters'' or ``otters,''
unless otherwise indicated) incidental to oil and gas exploration,
development, production, and transportation activities in Cook Inlet,
Alaska, for a period of 5 years. On June 28, 2018, the applicant
submitted an amended request providing additional project details. In
March 2019, Hilcorp and Harvest notified the Service that three-
dimensional (3D) seismic survey activities originally planned to begin
in April 2019 would be delayed until fall 2019. In June 2019, AGDC,
Hilcorp, and Harvest also provided an updated application package at
the request of the Service. The updated application clarified project
details and provided additional information where necessary to respond
to questions and concerns raised by comments received during the public
review of the proposed ITR. These updates and clarifications were minor
and did not significantly change the analysis of effects or the
estimates of take, and did not alter the conclusions regarding whether
the planned activities would have a negligible impact on the stocks,
would affect subsistence use, or would affect more than a small number
Summary of Changes From the Proposed ITR
In preparing this final regulation for the incidental take of sea
otters, we reviewed and considered comments and information from the
public on our proposed rule published in the Federal Register on March
19, 2019 (84 FR 10224), for which the comment period was extended by
notice in the Federal Register on April 5, 2019 (84 FR 13603). We also
reviewed and considered comments and information from the public for
our draft Environmental Assessment (EA). Based on those considerations,
and the new information provided by the applicant, we are finalizing
these regulations with the following changes from our proposed rule:
Table 1 and table 3 were updated to reflect the most
recent project details available from the applicant.
The Description of Specified Activities and table 1 were
appended to include redevelopment of existing wells at Granite Point.
Mitigation measures were added or modified in Sec.
18.137(b)(1)(ii), (b)(4)(ii), (b)(7)(ii), (b)(9), (c)(2), (c)(3),
(e)(4), and Sec. 18.140(b) of this final rule.
The total estimated number of Level B takes was adjusted
from 1,663 to 1,684 after the analysis was updated to reflect updates
in the project plans.
The duration of activities used in the estimation of take
was adjusted to reflect the maximum number of days during which
underwater work may generate noise above thresholds for take. The
following adjustments were made: Vibratory sheet pile driving was
adjusted from 5 to 20 days, Lower Cook Inlet (LCI) pipe driving was
revised from 3 to 12 days, Trading Bay (TB) pipe driving was revised
from 1.5 to 6 days, vertical seismic profiling (VSP) in LCI was changed
from 2 to 8 days, VSP in TB was adjusted from 1 to 4 days, and use of
water jets was increased from 10.5 to 21 days.
The analyses of take tables were updated to remove tugs
towing rigs and use of hydraulic grinders at the request of the
applicant and after analysis of take using the updated duration for
these sources indicated that take was unlikely.
Field verifications of sound production during two-
dimensional (2D) and 3D seismic surveys have been added to the required
A discussion of the alternative mitigation measures
evaluated but not required has been added.
Use of a mitigation gun was changed from required
mitigation for 2D and 3D seismic surveys to a measure that may be
required in LOAs issued under this ITR.
Table 9 was added to clarify allocation of sea otter take
by location of activity relative to the appropriate stock boundary.
Total estimated Level A take was adjusted from three takes
from the southcentral Alaska stock to one take from the southwest
Alaska stock and two takes from the southcentral Alaska stock. This
change was made to correct an error in the proposed ITR.
A mitigation measure was added requiring an applicant for
an LOA to evaluate alternatives to pile-supported facilities and
establishing that the Service may require sound-attenuation devices or
alternatives to pile-supported designs.
The Estimated Incidental Take section was updated to
reflect changes to the analysis due to the updated project details and
to provide additional clarity in the analysis methods used.
The evaluation of impacts of the specified activities was
modified throughout the document to focus on the total numbers of takes
rather than the numbers of individual sea otters taken. This change was
needed to ensure the estimates from the analysis were accurate and did
not underestimate take.
Description of the Regulation
This regulation does not authorize the specified activities to be
conducted by the applicant. Rather, it authorizes the nonlethal
incidental, unintentional take of small numbers of sea otters
associated with those planned activities based on standards set forth
in the MMPA. The ITR includes: Permissible amounts and methods of
nonlethal taking; measures to ensure the least practicable adverse
impact on sea otters and their habitat; measures to avoid and reduce
impacts to subsistence uses; and requirements for monitoring and
Description of the ITR Geographic Area
The geographic region of the ITR encompasses Cook Inlet, Alaska,
south of a line from the Susitna River Delta to Point Possession
(approximately 61[deg]15'54'' N, 150[deg]41'07'' W, to 61[deg]02'19''
N, 150[deg]23'48'' W, WGS 1984) and north of a line from Rocky Cove to
Coal Cove (at approximately 59[deg]25'56'' N, 153[deg]44'25'' W and
59[deg]23'48'' N, 151[deg]54'28'' W WGS 1984), excluding Ursus Cove,
Iniskin Bay, Iliamna Bay, and Tuxedni Bay (see Regulation Promulgation,
Sec. 18.131 Specified geographic region where this subpart applies).
The ITR area includes all Alaska State waters and Outer Continental
Shelf (OCS) Federal waters within this area as well as all adjacent
rivers, estuaries, and coastal lands where sea otters may occur, unless
The geographical extent of the Cook Inlet ITR region is
approximately 1.1 million hectares (ha) (2.7 million acres (ac)). For
descriptive purposes, the specified area is organized into two marine
areas within Cook Inlet: LCI (south of the Forelands to Homer) and
middle Cook Inlet (MCI; north of the Forelands to the Susitna River and
Point Possession). Project sites within these general areas include TB,
Granite Point, and the North Cook Inlet unit (NCI) in the MCI, and the
Iniskin Peninsula and the OCS waters of LCI.
Description of Specified Activities
The specified activities (also ``project activities'' or ``planned
activities'') include work related to oil and gas exploration,
development, production, transport, and the decommissioning of existing
facilities conducted by the applicant within a 5-year period. Hilcorp
and Harvest jointly plan to conduct the following activities: 2D and 3D
seismic surveys in LCI; routine operations of, maintenance of,
redevelopment of, and production drilling from existing oil and gas
facilities in MCI; geophysical and geohazard surveys in both regions;
drilling of two to four exploration wells in OCS waters of LCI and one
to three wells in MCI; construction of a dock facility in Chinitna Bay;
and decommissioning of an existing facility at the Drift River Terminal
in MCI. The following support activities will be conducted: Pipe and
pile driving using both vibratory and impact hammers; VSP; and pipeline
and platform maintenance. AGDC plans to install a natural gas pipeline
from the west side of MCI to the east side of LCI and to construct
processing and loading facilities on either side. These include a
product loading facility (PLF) and temporary and mainline materials
offloading facilities (TMOF, MMOF, MOF). Support activities for AGDC
will include pile driving, dredging, geophysical surveys, trenching,
fill placement, and anchor handling. Hilcorp, Harvest, and AGDC will
use vessels and aircraft to support the activities. Detailed
descriptions of the planned work are provided in the applicant's
updated petition for incidental take regulations for oil and gas
activities in Cook Inlet (June 2019), the stakeholder engagement plan
(April 2018), and the marine mammal monitoring and mitigation plan (May
2018). These documents can be obtained from the locations described
above in ADDRESSES. Table 1 summarizes the planned activities.
Table 1--Summary of Planned Activities Included in Incidental Take Regulation Petition
Project component name & Geographic Year(s) anticipated
location region planned Seasonal timing duration (2019-
Anchor Point 2D seismic LCI, Anchor 2021 or 2022 April-October................ 30 days (10 days
survey. Point to in water
OCS 3D seismic survey........ LCI OCS......... 2019 or 2020 April-October................ 45-60 days.
OCS geohazard survey......... LCI OCS......... 2019-2021 April-October................ 28 days.
OCS exploratory wells........ LCI OCS......... 2020-2022 February-November............ 40-60 days per
well, 2-4 wells
Iniskin Peninsula exploration LCI, west side.. 2020-2022 April-October................ 180 days.
Platform & pipeline MCI............. 2019-2024 April-October................ 180 days per
NCI subsea well geohazard MCI............. 2020 April-October................ 7 days.
NCI well abandonment activity MCI............. 2020 April-October................ 90 days.
TB area geohazard survey..... MCI............. 2020 April-October................ 14 days.
Granite Point development MCI............. 2019 June-October................. 120-150 days.
Drift River terminal LCI, west side.. 2020-2023 April-October................ 120 days.
Product loading facility pile MCI............. 2021-2023 April-October................ 162 days.
Material offloading MCI............. 2021-2022 April-October................ 360 days.
Material offloading MCI............. 2021-2022 April-October................ 482 days.
facilities pile driving.
Trenching, pipelay, burial... MCI............. 2023-2024 April-October................ 360 days.
Pipelay anchor handling...... MCI............. 2023-2024 April-October................ 76 days.
LCI = Lower Cook Inlet, MCI = Middle Cook Inlet, NCI = North Cook Inlet, TB = Trading Bay.
Description of Marine Mammals in the Specified Area
The northern sea otter is the only marine mammal under the
Service's jurisdiction that normally occupies Cook Inlet, Alaska. Sea
otters in Alaska are composed of three stocks. Those in Cook Inlet
belong to either the southwest Alaska stock or the southcentral Alaska
stock, depending on whether they occur west or east of the center of
Cook Inlet, respectively. A third stock occurs in southeast Alaska.
The southwest Alaska stock of the northern sea otter is the
southwest distinct population segment (DPS), which was listed as
threatened under the Endangered Species Act of 1973 (ESA; 16 U.S.C.
1531, et seq.) on August 9, 2005 (70 FR 46366). On October 8, 2009 (74
FR 51988), the Service finalized designation of 15,164 square
kilometers (km\2\) (or 5,855 square miles (mi\2\)) of critical habitat
for the Southwest DPS of sea otters. Critical habitat occurs in
nearshore marine waters ranging from the mean high-tide line seaward
for a distance of 100 meters (m), or to a water depth of 20 m. Detailed
information about the biology and conservation status of the listed DPS
can be found at https://www.fws.gov/alaska/fisheries/mmm/seaotters/otters.htm. Stock assessment reports for each of the three stocks are
available at https://www.fws.gov/alaska/pages/marine-mammal-management.
Sea otters may occur anywhere within the specified project area,
other than upland areas, but are not usually found north of about
60[deg]23'30'' N. The number of sea otters in Cook Inlet was estimated
from an aerial survey conducted by the Service in cooperation with the
U.S. Geological Survey (USGS) in May 2017 (Garlich-Miller et al. 2018).
The sea otter survey was conducted in all areas of Cook Inlet south of
approximately 60[deg]16'30'' N within the 40-m (131-feet (ft)) depth
contour, including Kachemak Bay in southeastern Cook Inlet and Kamishak
Bay in southwestern Cook Inlet. This survey was designed to estimate
abundance in Cook Inlet while accounting for the variable densities and
observability of sea otters in the region. Total abundance was
estimated to be 19,889 sea otters (standard error = 2,988). Within the
project area, the highest densities of sea otters were found in the
outer Kamishak Bay area, with 3.5 otters per km\2\, followed by the
eastern shore of Cook Inlet with 1.7 otters per km\2\.
Sea otters generally occur in shallow water near the shoreline.
They are most commonly observed within the 40-m (131-ft) depth contour
(USFWS 2014a, b), although they can be found in areas with deeper
water. Depth is generally correlated with distance to shore, and sea
otters typically remain within 1 to 2 kilometers (km) or 0.62 to 1.24
miles (mi) of shore (Riedman and Estes 1990). They tend to remain
closer to shore during storms, and they venture farther
out during calm seas (Lensink 1962; Kenyon 1969).
Sea otters are non-migratory and generally do not disperse over
long distances (Garshelis and Garshelis 1984). They usually remain
within a few kilometers of their established feeding grounds (Kenyon
1981). Breeding males remain for all or part of the year in a breeding
territory covering up to 1 km (0.62 mi) of coastline. Adult females
have home ranges of approximately 8 to 16 km (5 to 10 mi), which may
include one or more male territories. Juveniles move greater distances
between resting and foraging areas (Lensink 1962; Kenyon 1969; Riedman
and Estes 1990; Tinker and Estes 1996).
Although sea otters generally remain local to an area, they may
shift home ranges seasonally, and are capable of long-distance travel.
Otters in Alaska have shown daily movement distances greater than 3 km
(1.9 mi) at speeds up to 5.5 km/hr (3.4 mi per hour) (Garshelis and
Garshelis 1984). In eastern Cook Inlet, large numbers of sea otters
have been observed riding the incoming tide northward and returning on
the outgoing tide, especially in August. They are presumably feeding
along the eastern shoreline of Cook Inlet during the slack tides when
the seas are calm, and they remain in Kachemak Bay during periods of
less favorable weather (Gill et al. 2009; BlueCrest 2013). In western
Cook Inlet, otters appear to move in and out of Kamishak Bay in
response to seasonal changes in the presence of sea ice (Larned 2006).
Potential Effects of the Activities
Effects of Noise
The operations outlined in the Description of Specified Activities
and described in the applicant's updated petition have the potential to
result in take of sea otters by harassment from noise. Here we
characterize ``noise'' as sound released into the environment from
human activities that exceeds ambient levels or interferes with normal
sound production or reception by sea otters. The terms ``acoustic
disturbance'' or ``acoustic harassment'' are disturbances or harassment
events resulting from noise exposure. Potential effects of noise
exposure are likely to depend on the distance of the otter from the
sound source and the level of sound received by the otter. Project
components most likely to cause acoustic disturbance are shown in table
2. Temporary disturbance or localized displacement reactions are the
most likely to occur. With implementation of the mitigation and
monitoring measures described in Sec. 18.137 Mitigation, Sec. 18.138
Monitoring, and Sec. 18.139 Reporting requirements, no lethal take is
anticipated, and take by harassment (Level A and Level B) is expected
to be minimized to the greatest extent practicable.
Table 2--Project Components Planned by Hilcorp, Harvest, and Alaska
Gasline Development Corporation That Produce Noise Capable of Causing
Incidental Take by Harassment of Northern Sea Otters
Project component name &
location Anticipated noise sources
Anchor Point 2D seismic Marine: 1 source vessel with airgun, 1
survey. node vessel; Onshore/Intertidal: Shot
holes, tracked vehicles, helicopters.
OCS 3D seismic survey........ 1 source vessel with airguns, 1 support
vessel, 1 or 2 chase vessels to maintain
security around streamers, 1 or 2
OCS geohazard survey......... 1 vessel with echosounders and/or
OCS exploratory wells........ 1 jack-up rig, drive pipe installation,
support vessels, helicopters.
Iniskin Peninsula exploration Construction of causeway, dredging,
and development. vessels.
Platform & pipeline Vessels, water jets, helicopters, and/or
maintenance. sub-bottom profilers.
NCI subsea well geohazard 1 vessel with echosounders and/or
survey. subbottom profilers.
NCI well abandonment activity 1 jack-up rig, support vessel,
TB area geohazard survey..... 1 vessel with echosounders and/or
TB area exploratory wells.... 1 jack-up rig, drive pipe installation,
support vessels, helicopters.
Drift River terminal Vessels.
OCS = outer continental shelf, NCI = North Cook Inlet, TB = Trading Bay.
Whether a specific noise source will affect a sea otter depends on
several factors, including the distance between the animal and the
sound source, the sound intensity, background noise levels, the noise
frequency, the noise duration, and whether the noise is pulsed or
continuous. The actual noise level perceived by individual sea otters
will depend on distance to the source, whether the animal is above or
below water, atmospheric and environmental conditions, as well as
aspects of the noise emitted.
Noise levels herein are given in decibels referenced to 1 [mu]Pa
(dB re: 1 [mu]Pa) for underwater sound. All dB levels are
dBRMS unless otherwise noted; dBRMS refers to the
root-mean-squared dB level, the square root of the average of the
squared sound pressure level (SPL) typically measured over 1 second.
Other important metrics include the sound exposure level (SEL;
represented as dB re: 1 [mu]Pa\2\-s), which represents the total energy
contained within a pulse and considers both intensity and duration of
exposure, and the peak sound pressure (also referred to as the zero-to-
peak sound pressure or 0-p). Peak sound pressure is the maximum
instantaneous sound pressure measurable in the water at a specified
distance from the source and is represented in the same units as the
RMS sound pressure. See Richardson et al. (1995), G[ouml]tz et al.
(2009), Hopp et al. (2012), Navy (2014), for descriptions of acoustical
terms and measurement units in the context of ecological impact
assessment. A summary of the noises produced by the various components
of the planned activities is provided in tables 3 and 4.
Table 3--Summary of Sound Source Levels for the Planned Oil and Gas Activities by Hilcorp/Harvest Alaska and
Alaska Gasline Development Corporation (AGDC)
Applicant Activity levels (dB re 1 Frequency Reference
Hilcorp/Harvest Alaska, AGDC.... General vessel 145-175 dB rms at 10-1,500 Hz....... Richardson et al.
operations. 1 m. 1995; Blackwell
and Greene 2003;
Hilcorp/Harvest Alaska, AGDC.... General aircraft 100-124 dB rms at <500 Hz........... Richardson et al.
operations. 1 m. 1995.
Hilcorp/Harvest Alaska.......... 2D seismic survey 217 dB peak at 100 <300 Hz........... Austin and Warner
(1,945 cui m. 2013; 81 FR 47240
airgun). 185 dB SEL at 100 (July 20, 2016).
197 dB rms at 100
Hilcorp/Harvest Alaska.......... 3D seismic survey 217 dB peak at 100 <300 Hz........... Austin and Warner
(1,945 cui m. 2013; 81 FR 47240
airgun). 185 dB SEL at 100 (July 20, 2016).
197 dB rms at 100
Hilcorp/Harvest Alaska.......... Geohazard surveys. 210-220 dB rms at Echosounders & Manufacturer
1 m. side scan sonar: specifications.
Hilcorp/Harvest Alaska.......... Exploratory 137 dB rms at 1 m. <200 Hz........... Marine Acoustics
drilling rig. Inc. 2011.
Hilcorp/Harvest Alaska.......... Drive pipe 190 dB rms at 55 m <500 Hz........... Illingworth &
installation. Rodkin 2014.
Hilcorp/Harvest Alaska.......... Vertical seismic 227 dB rms at 1 m. <500 Hz........... Illingworth &
profiling. Rodkin 2014.
Hilcorp/Harvest Alaska.......... Sub-bottom 212 dB rms at 1 m. 1-24 kHz.......... Manufacturer
Hilcorp/Harvest Alaska.......... Rock laying for 136-141 dB rms at <500 Hz........... URS 2007.
Iniskin Peninsula 12-19 m.
Hilcorp/Harvest Alaska.......... Vibratory sheet 175 dB peak at 10 <100-2,500 Hz..... Illingworth &
pile driving for m. Rodkin 2007.
Iniskin Peninsula 160 dB SEL at 10 m
causeway. 160 dB rms at 10 m
Hilcorp/Harvest Alaska.......... Offshore 97-111 dB rms at <500 Hz........... Blackwell and
production 0.3-19 km. Greene 2003.
Hilcorp/Harvest Alaska.......... Water jet......... 176 dB rms at 1 m. 500 Hz-2 kHz...... Austin 2017.
Hilcorp/Harvest Alaska.......... Pingers........... 192 dB rms at 1 m. 4-14 kHz.......... Manufacturer
AGDC............................ Dredging: 107-142.6 dB rms <2.5 kHz, Dickerson et al.
Including at 10 m. broadband. 2001; URS 2007.
AGDC............................ Underwater 145 dB @10 m...... <2.5 kHz, Greene et al.
trenching with broadband. 2008.
AGDC............................ Anchor handling... 188 dB rms @1 m... <2.5 kHz, LGL/JASCO/
broadband. Greeneridge 2014.
SEL = sound exposure level.
Table 4--Summary of Sound Sources of Pile-Driving Activities for Alaska Gasline Development Corporation (AGDC) From Illingworth & Rodkin (2007).
Sound pressure level (dB re 1
Representative pile type and size Hammer type --------------------------------------- Project pile type and size
Peak RMS SEL
24-inch sheet pile.................... Impact...................... 205 190 180 Sheet pile.
24-inch sheet pile.................... Vibratory................... 175 160 160 Sheet pile.
24-inch steel pipe pile............... Impact...................... 207 194 178 18- and 24-inch piles.
60-inch steel shell pile.............. Impact...................... 210 195 185 48- and 60-inch piles.
72-inch steel pipe piles.............. Vibratory................... 183 170 170 All size piles.
Sea Otter Hearing
Sound frequencies produced by the applicant's survey and
construction activities will fall within the hearing range of sea
otters and therefore will be audible to animals. Controlled sound
exposure trials on southern sea otters (E. l. nereis) indicate that
hearing ability spans frequencies between 125 hertz (Hz) and 38
kilohertz (kHz) with best sensitivity between 1.2 and 27 kHz (Ghoul and
Reichmuth 2014). Aerial and underwater audiograms for a captive adult
male southern sea otter in the presence of ambient noise suggest the
sea otter's hearing was less sensitive to high-frequency (greater than
22 kHz) and low-frequency (less than 2 kHz) sounds than terrestrial
mustelids but similar to that of a sea lion (e.g., Zalophus
californianus). Dominant frequencies of southern sea otter
vocalizations are between 3 and 8 kHz, with some energy extending above
60 kHz (McShane et al. 1995; Ghoul and Reichmuth 2012a).
Exposure to high levels of sound may cause changes in behavior,
masking of communications, temporary changes in hearing sensitivity,
discomfort, and physical or auditory injury. Species-specific criteria
for preventing harmful exposures to sound have not been identified for
sea otters. Thresholds have been developed for other marine mammals,
above which exposure is likely to cause behavioral disturbance and
injuries (Southall et al. 2007; Finneran and Jenkins 2012; NMFS 2018a).
Because sea otter hearing abilities and sensitivities have not been
fully evaluated, we relied on the closest related proxy, California sea
lions, to evaluate the potential effects of noise exposure. The
California sea lion, an otariid pinniped, has a frequency range of
hearing most similar to that of the southern sea otter (Ghoul and
Reichmuth 2014) and provides the closest related proxy for which data
are available. Sea otters and pinnipeds
share a common mammalian aural physiology (Echteler et al. 1994;
Solntseva 2007). Both are adapted to amphibious hearing, and both use
sound in the same way (primarily for communication rather than
Noise exposure criteria have been established by the National
Marine Fisheries Service (NMFS) for identifying underwater noise levels
capable of causing Level A harassment (injury) of certain marine
mammals, including otariid pinnipeds (NMFS 2018a). Sea otter-specific
criteria have not been determined; however, because of their biological
similarities, we assume that noise criteria developed by NMFS for
injury for otariid pinnipeds will be a suitable surrogate for sea otter
impacts as well. Those criteria are based on estimated levels of sound
exposure capable of causing a permanent shift in sensitivity of hearing
(e.g., a permanent threshold shift (PTS) (NMFS 2018a)). PTS occurs when
noise exposure causes hairs within the inner ear system to die.
NMFS' (2018a) criteria for sound exposure incorporate two metrics
of exposure: The peak level of instantaneous exposure likely to cause
PTS, and the cumulative sound exposure level during a 24-hour period
(SELcum). They also include weighting adjustments for the
sensitivity of different species to varying frequencies. PTS-based
injury criteria were developed from theoretical extrapolation of
observations of temporary threshold shifts (TTS) detected in lab
settings during sound exposure trials. Studies were summarized by
Finneran (2015). For otariid pinnipeds, PTS is predicted to occur at
232 dB peak or 203 dB SELcum for impulsive sound, or 219 dB
SELcum for non-impulsive (continuous) sound.
NMFS' criteria for take by Level A harassment represents the best
available information for predicting injury from exposure to underwater
sound among pinnipeds, and in the absence of data specific to otters,
we assume these criteria also represent appropriate exposure limits for
Level A take of sea otters.
NMFS (2018a) criteria do not identify thresholds for avoidance of
Level B take. For pinnipeds, NMFS has adopted a 160-dB threshold for
Level B take from exposure to impulse noise and a 120-dB threshold for
continuous noise (NMFS 1998; HESS 1999; NMFS undated). These thresholds
were developed from observations of mysticete (baleen) whales
responding to airgun operations (e.g., Malme et al. 1983a, b;
Richardson et al. 1986, 1995) and from equating Level B take with noise
levels capable of causing TTS in lab settings.
We have evaluated these thresholds and determined that the Level B
threshold of 120 dB for non-impulsive noise is not applicable to sea
otters. The 120-dB threshold is based on studies conducted by Malme et
al. in the 1980s, during which gray whales were exposed to experimental
playbacks of industrial noise. Based on the behavioral responses of
gray whales to the playback of drillship noise during a study at St.
Lawrence Island, Alaska, Malme et al. (1988) concluded that ``exposure
to levels of 120 dB or more would probably cause avoidance of the area
by more than one-half of the gray whales.'' Sea otters do not usually
occur at St. Lawrence Island, Alaska, but similar playback studies
conducted off the coast of California (Malme 1983a, 1984) included a
southern sea otter monitoring component (Riedman 1983, 1984). The 1983
and 1984 studies detected probabilities of avoidance in gray whales
comparable to those reported in Malme et al. (1988), but there was no
evidence of disturbance reactions or avoidance in southern sea otters.
The applicable Level B thresholds may also depend on the levels of
background noise present and the frequencies generated. NMFS
acknowledges that the 120-dB threshold may not be applicable if
background noise levels are high (NMFS undated), which is the case in
Cook Inlet, where ambient levels can often exceed 120 dB (Blackwell and
Thresholds developed for one species may not be appropriate for
another due to differences in their frequency sensitivities. Continuous
sound sources associated with the planned activities include vibratory
pile driving, vessel activities, use of a water jet, dredging,
trenching, and anchor handling. These are expected to produce low-
frequency broadband noise. For example, vibratory pile driving will
generate sound with frequencies that are predominantly lower than 2
kHz, and with the greatest pressure spectral densities at frequencies
below 1 kHz (Dahl et al. 2015). Sea otters are capable of hearing down
to 125 Hz, but have relatively poor hearing sensitivity at frequencies
below 2 kHz (Ghoul and Reichmuth 2014). During a project that occurred
in Elkhorn Slough, California, sound levels ranging from approximately
135 to 165 dB during vibratory pile driving elicited no clear pattern
of disturbance or avoidance among southern sea otters in areas exposed
to these levels of underwater sound (ESNERR 2011). In contrast, gray
whales are in the group of marine mammals believed to be most sensitive
to low-frequency sounds, with an estimated audible frequency range of
approximately 10 Hz to 30 kHz (Finneran 2015). Given the different
range of frequencies to which sea otters and gray whales are sensitive,
the NMFS 120-dB threshold based on gray whale behavior is not useful
for predicting sea otter behavioral responses to low-frequency sound.
Although no specific thresholds have been developed for sea otters,
several alternative behavioral response thresholds have been developed
for pinnipeds. Southall et al. (2007, 2019) assessed behavioral
response studies, found considerable variability among pinnipeds, and
determined that exposures between approximately 90 to 140 dB generally
do not appear to induce strong behavioral responses in pinnipeds in
water, but behavioral effects, including avoidance, become more likely
in the range between 120 to 160 dB, and most marine mammals showed
some, albeit variable, responses to sound between 140 to 180 dB. Wood
et al. (2012) later adapted the approach identified in Southall et al.
(2007) to develop a probabilistic scale for marine mammal taxa at which
10 percent, 50 percent, and 90 percent of individuals exposed are
assumed to produce a behavioral response. For many marine mammals,
including pinnipeds, these response rates were set at sound pressure
levels of 140, 160, and 180 dB respectively.
Thresholds based on TTS have been used as a proxy for Level B
harassment (i.e., 70 FR 1871, January 11, 2005; 71 FR 3260, January 20,
2006; and 73 FR 41318, July 18, 2008). Southall et al. (2007) derived
TTS thresholds for pinnipeds based on 212 dB peak and 171-dB
SELcum. Kastak et al. (2005) found exposures resulting in
TTS in pinnipeds ranging from 152 to 174 dB (183-206 dB SEL). Kastak et
al. (2008) demonstrated a persistent TTS, if not a PTS, after 60
seconds of 184 dB SEL. Kastelein et al. (2012) found small but
statistically significant TTSs at approximately 170 dB SEL (136 dB, 60
min) and 178 dB SEL (148 dB, 15 min). Finneran (2015) summarized these
and other studies, and NMFS (2018a) has used the data to develop TTS
threshold for otariid pinnipeds of 188 dB SELcum for
impulsive sounds and 199 dB SELcum for non-impulsive sounds.
Based on the lack of a disturbance response or any other reaction
by sea otters to the 1980s playback studies and the absence of a clear
pattern of disturbance or avoidance behaviors attributable to
underwater sound levels up to about 160 dB resulting from
vibratory pile driving and other sources of similar low-frequency
broadband noise, we assume 120 dB is not an appropriate behavioral
response threshold for sea otters exposed to continuous underwater
noise. We assume, based on the work of NMFS (2018a), Southall et al.
(2007, 2019), and others described here, that either a 160-dB threshold
or a 199-dB SELcum threshold is likely to be the best
predictor of Level B take of sea otters for continuous noise exposure,
using southern sea otters and pinnipeds as a proxy, and based on the
best available data. When behavioral observations during vibratory pile
driving (ESNERR 2011) and results of behavioral response modelling
(Wood et al. 2012) are considered, the application of a 160-dB rms
threshold is most appropriate.
Exposure to impulsive sound levels greater than 160 dB can elicit
behavioral changes in marine mammals that might be detrimental to
health and long-term survival where it disrupts normal behavioral
routines. Thus, using information available for other marine mammals as
a surrogate, and taking into consideration the best available
information about sea otters, the Service has set the received sound
level under water of 160 dB as a threshold for Level B take by
disturbance for sea otters for this ITR based on the work of Ghoul and
Reichmuth (2012a, b), McShane et al. (1995), NOAA (2005), Riedman
(1983), Richardson et al. (1995), and others. Exposure to unmitigated
in-water noise levels between 125 Hz and 38 kHz that are greater than
160 dB--for both impulsive and non-impulsive sound sources--will be
considered by the Service as Level B take; thresholds for potentially
injurious Level A take will be 232 dB peak or 203 dB SEL for impulsive
sounds and 219 dB SEL for continuous sounds (table 5).
The area in which underwater noise in the frequency range of sea
otter hearing will exceed thresholds, is termed the ``area of
ensonification'' or ``zone of ensonification.'' The ensonification zone
in which noise levels exceed thresholds for Level A take is often
referred to as the Level A harassment zone. The Level B harassment zone
likewise includes areas ensonified to thresholds for Level B take of
Table 5--Summary of Thresholds for Predicting Level A and Level B Take of Northern Sea Otters From Underwater
Sound Exposure in the Frequency Range 125
Injury (Level A) threshold Disturbance (Level B) threshold
Marine mammals -------------------------------------------------------------------------------
Impulsive \1\ Non-impulsive \1\ All
Sea otters...................... 232 dB peak; 203 dB 219 dB SELCUM...... 160 dB rms.
\1\ Based on National Marine Fisheries Service acoustic exposure criteria for take of otariid pinnipeds (NMFS
SELCUM = cumulative sound exposure level.
The components of the specified activities that have the greatest
likelihood of exposing sea otters to underwater noise capable of
causing Level A or Level B take include geophysical surveys, pile
driving, drilling activities, and anchor handling associated with
pipeline construction. Vessel and aircraft operations also have the
ability to expose otters to sound that may cause disturbance. A brief
description of potential impacts follows.
Geophysical Surveys--Airgun arrays used in seismic surveys to
locate potential hydrocarbon-bearing geologic formations typically
produce most noise energy in the 10- to 120-Hertz (Hz) range, with some
energy extending to 1,000 Hz (Richardson et al. 1995). There is no
empirical evidence that exposure to pulses of airgun sound is likely to
cause serious injury or death in any marine mammal, even with large
arrays of airguns (Southall et al. 2007). But high-level noise exposure
has been implicated in mass stranding events among whales (e.g., see
Cox et al. 2006), and with source levels of up to 260 dB, the potential
of seismic airgun arrays to acoustically injure marine mammals at close
proximity must be considered.
In addition to seismic surveys for hydrocarbon-bearing formations,
geophysical surveys are conducted to produce imagery of sea-floor
surfaces and substrates on a finer spatial scale. Sounds produced by
the instruments used for these surveys vary in terms of frequency
bands, source levels, repetition rates, and beam widths. Operating
frequencies range from roughly 300 Hz to several hundred kHz with peak-
to-peak source levels ranging from 170 to 240 dB (Crocker and
Pipe/Pile Driving--During the course of pile driving, a portion of
the kinetic energy from the hammer is lost to the water column in the
form of sound. Levels of underwater sounds produced during pile driving
are dependent upon the size and composition of the pile, the substrate
into which the pile is driven, bathymetry, physical and chemical
characteristics of the surrounding waters, and pile installation method
(impact versus vibratory hammer) (Illingworth and Rodkin 2007, 2014;
Denes et al. 2016).
Both impact and vibratory pile installation produce underwater
sounds of frequencies predominantly lower than 2.5 kHz, with the
highest intensity of pressure spectral density at or below 1 kHz (Denes
et al. 2016; Dahl et al. 2015; Illingworth and Rodkin 2007). Source
levels of underwater sounds produced by impact pile driving tend to be
higher than for vibratory pile driving; however, both methods of
installation can generate underwater sound levels capable of causing
behavioral disturbance or hearing threshold shift in marine mammals,
and both methods will be used in Cook Inlet.
Drilling Operations--For drilling operations, two project
components have the potential to disturb sea otters: Installing the
drive pipe at each well prior to drilling; and VSP operations that may
occur at the completion of each well drilling. The types of underwater
sounds generated by these activities are discussed in ``Pile Driving''
and ``Geophysical Surveys,'' respectively. Drilling and the associated
noise from pumps and generators on the drill rig is not expected to
produce underwater noise levels that will affect sea otters (e.g., see
Richardson et al. 1995; Spence et al. 2007; Marine Acoustics, Inc.
2011; Illingworth and Rodkin 2014).
Aircraft Overflights--Richardson et al. (1995) presented analyses
of recordings of sounds produced by a Bell 212 helicopter. The
estimated source levels for two of the flights were 149 and 151 dB re 1
[micro]Pa-m, and underwater received levels were 109 dB when the
aircraft flew at an altitude of 152 m (500 ft) and
107 dB at a flight altitude of 305 m (1,000 ft). Received sound levels
in air at the water surface would be 81 and 75 dB re 20 [micro]Pa for
flights at 152 and 305 m (500 and 1,000 ft), respectively.
Anchor Handling--The characteristics of sounds produced by vessels
are a product of several variables pertaining to the specifications of
the vessel, including the number and type of engines, propeller shape
and size, and the mechanical condition of these components. Operational
status of the vessel, such as towing heavy loads or using bow
thrusters, can significantly affect the levels of sounds emitted by the
same vessel at different times (Richardson et al. 1995). Manipulation
of anchors for the laying of the AGDC pipeline will involve vessel
operations that are likely to be substantially louder than normal
transit. Data from recent exploratory drilling activities in the
Chukchi and Beaufort Seas indicate that anchor handling can
intermittently produce sounds likely greater than 190 dB; the source
level of the anchor-handling vessel was estimated to be 188 dB (LGL/
JASCO/Greeneridge 2014). It is not known whether anchor handling will
produce similar noise levels in Cook Inlet, but it will occur in areas
where sea otters are uncommon and unlikely to be affected.
The NMFS (2018a) guidance neither addresses thresholds for
preventing injury or disturbance from airborne noise, nor provides
thresholds for avoidance of Level B take. However, a review of
literature by Southall et al. (2007) suggested thresholds for PTS and
TTS for sea lions exposed to non-pulsed airborne noise of 172.5 and 159
dB re (20 [micro]Pa)\2\-s SEL. Behavioral responses to overflights are
addressed in Responses to Activities.
Conveyance of underwater noise into the air is of little concern
since the effects of pressure release and interference at the water's
surface, which scatter and reflect sound, reduce underwater noise
transmission into the air. For activities that create both in-air and
underwater sounds, such as pile driving, we will estimate take based on
parameters for underwater noise transmission. Because sound energy
travels more efficiently through water than through air, this
estimation will also account for exposures to animals at the surface.
Aircraft are the most significant source of airborne sounds.
Proposed flights are to be conducted at an altitude of 305 m (1,000 ft)
except during takeoff and landing. At the surface of the water, the
received sound level from a helicopter flown at this altitude is
roughly 75 dB re 20 [micro]Pa (see ``Noise-Generating Activities''),
and so threshold shift is extremely unlikely.
Loud screams are used to communicate between pups and mothers at
the surface (McShane et al. 1995), but sea otters do not appear to
communicate vocally under water, and they do not use sound to detect
prey. Although masking of these crucial airborne calls is possible, the
duration of sound from aircraft will be brief and therefore unlikely to
result in separation of females from pups.
Effects on Habitat and Prey
Habitat areas of significance for sea otters exist in the project
area. Sea otter critical habitat was designated under the ESA (74 FR
51988, October 8, 2009). In Cook Inlet, critical habitat occurs along
the western shoreline south of approximately Redoubt Point. It extends
from mean high-tide line out to 100 m (328.1 ft) from shore or to the
20-m (65.6-ft) depth contour. Physical and biological features of
critical habitat essential to the conservation of sea otters include
the benthic invertebrates (e.g., red sea urchins (Mesocentrotus
franciscanus), blue mussels (Mytilus spp.), butter clams (Saxidomus
giganteus), etc.) eaten by otters and the shallow rocky areas and kelp
(e.g., bull kelp (Nereocystis luetkeana) and dragon kelp (Eualaria
fistulosa)) beds that provide cover from predators. Other important
habitat in the applicant's project area includes outer Kamishak Bay
between Augustine Island and Iniskin Bay within the 40-m (131-ft) depth
contour where high densities of otters have been detected.
The applicant's planned activities include drilling, dredging,
trenching, pile driving, and dock construction. These activities would
change the physical characteristics of localized areas of habitat.
Construction would result in seafloor disturbance. Docks can increase
seafloor shading, which affects the amount of light penetration on the
seafloor. Water quality may be affected by drilling-related discharges
within limits permitted by the State of Alaska.
Sampling efforts at borrow and disposal areas before and after
dredging activity have produced mixed results in terms of whether
dredging causes significant changes to the productivity and diversity
of infaunal benthic and epibenthic invertebrate communities (Fraser et
al. 2017; Angonesi et al. 2006). The areas where dredging activities
are proposed include a materials loading facility at Nikiski and along
the planned AGDC pipeline route between Nikiski and Beluga; the
proposed disposal area is just west of Nikiski. This is beyond the
northern limit of sea otter distribution in Cook Inlet, so effects of
dredging upon invertebrate communities would not affect availability of
prey to sea otters.
In addition to the disturbances outlined above to sea otters or
their designated critical habitat, survey and construction activities
could affect sea otter habitat in the form of impacts to prey species.
The primary prey species for sea otters are sea urchins, abalone,
clams, mussels, crabs, and squid (Tinker and Estes 1999). When
preferential prey are scarce, otters will also eat kelp, turban snails
(Tegula spp.), octopuses (e.g., Octopus spp.), barnacles (Balanus
spp.), sea stars (e.g., Pycnopodia helianthoides), scallops (e.g.,
Patinopecten caurinus), rock oysters (Saccostrea spp.), worms (e.g.,
Eudistylia spp.), and chitons (e.g., Mopalia spp.) (Riedman and Estes
Limited research has been conducted on the effects of noise on
invertebrates (Normandeau Associates, Inc. 2012). Christian et al.
(2003) concluded that there were no obvious effects from seismic
signals on crab behavior and no significant effects on the health of
adult crabs. Pearson et al. (1994) had previously found no effects of
seismic signals upon crab larvae for exposures as close as 1 m (3.3 ft)
from the array, or for mean sound pressure as high as 231 dB. Pearson
et al. (1994) did not observe any statistically significant effects on
Dungeness crab (Cancer magister) larvae shot as close as 1 m from a
231-dB source. Further, Christian et al. (2004) did not find any
behavioral or significant health impacts to snow crabs (Chionoecetes
opilio) exposed to seismic noise. The only effect noted was a reduction
in the speed of egg development after exposure to noise levels (221 dB
at 2 m), far higher than what bottom-dwelling crabs could be exposed to
by seismic guns. Invertebrates such as mussels, clams, and crabs do not
have auditory systems or swim bladders that could be affected by sound
pressure. Squid and other cephalopod species have complex statocysts
(Nixon and Young 2003) that resemble the otolith organs of fish that
may allow them to detect sounds (Budelmann 1992).
Some species of invertebrates have shown temporary behavioral
changes in the presence of increased sound levels. Fewtrell and
McCauley (2012) reported increases in alarm behaviors in wild-caught
captive reef squid (Sepioteuthis australis) exposed to seismic airguns
at noise levels between 156-161 dB. Additionally, captive crustaceans
changed behaviors when exposed to simulated sounds consistent with
those emitted during seismic exploration and pile-driving activities
(Tidau and Briffa 2016).
In general, there is little knowledge regarding effects of sound in
marine invertebrates or how invertebrates are affected by high noise
levels (Hawkins and Popper 2012). A review of literature pertaining to
effects of seismic surveys on fish and invertebrates (Carroll et al.
2016) noted that there is a wide disparity between results obtained in
field and laboratory settings. Some of the reviewed studies indicate
the potential for noise-induced physiological and behavioral changes in
a number of invertebrates. However, changes were observed only when
animals were housed in enclosed tanks and many were exposed to
prolonged bouts of continuous, pure tones. We would not expect similar
results in open marine conditions. Given the short-term duration of
sounds produced by each component of the proposed work, it is unlikely
that noises generated by survey and construction activities will have
any lasting effect on sea otter prey.
Potential Impacts From an Oil Spill or Unpermitted Discharge
We provided discussion of relevant impacts to sea otters from oil
spills and unpermitted discharges in our Federal Register notice of
proposed rulemaking (84 FR 10224, March 19, 2019) and do not repeat
that information here. Adverse impacts of exposure to oil is well
documented for sea otters (e.g., Kooyman et al. 1976; Baker et al.
1981; Costa and Kooyman 1982, 1984; Engelhardt 1983; Lipscomb 1996;
Bickham 1998; Monson 2000; Albers 2003; Peterson 2003). An oil spill or
unpermitted discharge is an illegal act, and ITRs do not authorize take
of sea otters caused by illegal or unpermitted activities. Typical
spills that may result from the proposed activities are relatively
small in scale and are not likely to affect otters. A large spill could
affect large numbers of otters, but these events are rare. We do not
anticipate effects to sea otters as a result of oil spills from this
Vessel collisions with marine mammals can result in death or
serious injury. Wounds resulting from ship strike may include massive
trauma, hemorrhaging, broken bones, or propeller lacerations (Knowlton
and Kraus 2001). An animal at the surface may be struck directly by a
vessel, a surfacing animal may hit the bottom of a vessel, or an animal
just below the surface may be cut by a vessel's propeller. Mortality
associated with boat strike has been identified from recovery of
carcasses with lacerations indicative of propeller injuries (e.g., Wild
and Ames 1974; Morejohn et al. 1975). From 1998 to 2001, boat strike
was identified as the cause of death for 5 of 105 southern sea otter
mortalities (Kreuder et al. 2003). From 2006 through 2010, evidence
indicates that 11 southern sea otters were likely struck by boats (USGS
and California Department of Fish and Game, unpublished data cited in
77 FR 59211-59220, September 26, 2012). From January 2003 to May 2013,
researchers recovered 35 southern sea otters with trauma consistent
with impact from a boat hull or propeller. These data suggest a rate of
boat-strike mortality in California of 2.6 otters per year, or about
0.1 percent of the population size.
Boat strike has been documented as a cause of death across all
three stocks of northern sea otters in Alaska. Since 2002, the Service
has undertaken a health and disease study of sea otters in Alaska in
which the Service conducts necropsies on sea otter carcasses to
determine cause of death, disease incidence, and status of general
health parameters. Of 1,433 necropsies conducted during 24 years, boat
strike or blunt trauma was identified as a definitive or presumptive
cause of death in 64 cases (4 percent) (USFWS unpublished data). It has
been determined in most of these cases that, while trauma was the
ultimate cause of death, there was a contributing factor, such as
disease or biotoxin exposure, which incapacitated the animal and made
it more vulnerable to boat strike (USFWS 2014).
In Alaska, the annual rate of documented mortality from boat strike
was similar to that reported for California: 2.7 otters per year (USFWS
unpublished data). However, compared to otters in California, Alaska
otters belong to much larger and more dispersed populations where
carcass recovery is lower. Instances of vessel collision are likely to
be underreported, and the probability of collision is unknown.
Likelihood of vessel strikes involving sea otters appears to be
primarily related to vessel speed. Most collision reports have come
from small, fast-moving vessels (NMFS 2003). The severity of injuries
to marine mammals during a boat strike also depends on vessel speed,
with the probability of death or serious injury increasing as vessel
speed increases (Laist et al. 2001; Vanderlaan and Taggart 2007).
Because sea otters spend a considerable portion of their time at the
surface of the water, they are typically visually aware of approaching
boats and are able to move away if a vessel is not traveling too
The probability of the specified activities in Cook Inlet causing a
sea otter/vessel collision is very low for three reasons: First, most
of the work will occur in lower-density regions of Cook Inlet; second,
the project work will involve slow-moving, noisy vessels that sea
otters can more easily avoid; and third, the specified activities will
constitute only a small fraction of the total level of vessel traffic
in the region, which increases the likelihood that otters in the
project area are accustomed to avoiding vessels and will successfully
avoid collisions with project vessels.
The AGDC pipeline work and work by Hilcorp and Harvest on
maintenance of existing facilities will be conducted in MCI, in areas
that are outside of the normal range of sea otters. The unusual
occurrence of otters in MCI makes vessel collisions extremely unlikely.
Hilcorp and Harvest will conduct their 3D seismic work in offshore
areas of LCI where otter densities are also low. They will conduct 2D
seismic work along the eastern shoreline of LCI where densities are
higher, but vessel speeds during the specified activities will be slow.
Hilcorp/Harvest's seismic vessels would travel at approximately 4 knots
(kn) or 7.4 km per hour (km/hr) while towing seismic survey gear and a
maximum of 4.5 kn (8.3 km/hr) while conducting geophysical surveys.
Vessel speed during rig towing will generally be less than 5 kn. AGDC's
pipeline construction operations will proceed at similar slow speeds.
Anchor handling will occur at about 3 kn. For comparison, freighters in
Cook Inlet travel at 20 to 24 kn (Eley 2006), and small recreational
vessels may travel at 40 kn.
The applicant's support vessels and vessels in transit will travel
at faster speeds; for example, Hilcorp/Harvest's maintenance activities
will require the use of dive vessels, typically ranging up to 21 m (70
ft) in length and capable of approximately 7 kn (13 km/hr). The risk of
collision is thus reduced, but not eliminated, by the predominance of
slow-moving vessel work in areas of low density.
Commercial and recreational vessels are much more common in both
space and time than are geophysical survey activities, drilling support
operations, and pipeline work. Based on U.S. Coast Guard records and
other local sources of information compiled by Eley (2006), 704 large
vessels, other than fuel barges in domestic trade, called at Cook Inlet
ports from January 1, 2005, through July 15, 2006. Almost two-thirds
of the calls were made by container vessels, cargo, or ferries. Twenty-
nine percent (29 percent) of the vessel traffic was gas or liquid
tankships calling primarily at Nikiski. Bulk carriers and general cargo
ships represented 6 percent. Tugs and fishing and passenger vessels
combined represented 2 percent of the Cook Inlet vessel traffic. Tugs
made approximately 150 fuel barge transits a year, assisted in docking
and undocking ships in Nikiski and Anchorage, and moved miscellaneous
deck and gravel barges in and out of the Port of Anchorage. Although
small vessels are less common than larger ships, they are the most
likely source of collision due to faster speeds and their presence in
shallow water where sea otters are common. In 2005, there were 570
commercial fishing vessels registered in the Cook Inlet salmon/
groundfish fleet. Of these, 86 percent were 31-40 ft in length. Vessels
in this size class typically travel at up to 30 kn while in transit.
The high level of ship traffic in Cook Inlet allows many sea otters in
Cook Inlet to habituate to vessels. This will reduce risk of collision
for the project activities when vessels are in transit.
Although the likelihood of a project vessel striking a sea otter is
low, we intend to require mitigation measures to reduce the risk of
ship strike in all LOAs. We anticipate that vessel collisions involving
a seismic-data-acquisition vessel towing gear or vessels conducting
geophysical operations are unlikely given the rarity of documented
collisions, the low densities of otters in most of the project areas,
the frequent vessel traffic to which otters have become accustomed, and
the slow vessel speeds. Vessels in transit and support vessels
travelling at greater rates of speed are more likely to cause
Mitigation measures for reducing the probability of ship strike
include speed reductions during periods of low visibility, required
separation distances from observed otters, avoidance of nearshore
travel, and use of navigation channels, when practicable. We believe
these measures will further reduce the risk of collision. Given the
required mitigation measures, the relatively slow speed of most of the
project vessels, the presence of marine mammal observers, and the short
duration of many of the activities, we believe that the possibility of
ship strike is discountable. No incidental take resulting from ship
strike is anticipated, and this potential effect of the specified
activity will not be discussed further in the following analysis.
In the previous section, we discussed the components of the project
activities that have the potential to affect sea otters. Here we
describe and categorize the physiological and behavioral effects that
can be expected based on documented responses to human activities
observed during sea otter studies. We also discuss how these behaviors
are characterized under the MMPA.
An individual sea otter's reaction to a human activity will depend
on its prior exposure to the activity, its need to be in the particular
area, its physiological status, or other intrinsic factors. The
location, timing, frequency, intensity, and duration of the encounter
are among the external factors that will also influence the animal's
Relatively minor reactions such as increased vigilance or a short-
term change in direction of travel are not likely to disrupt
biologically important behavioral patterns and are not considered take
by harassment. These types of responses typify the most likely
reactions of the majority of sea otters that will be exposed to the
Reactions capable of causing injury are characterized as Level A
harassment events. Examples include separation of mothers from young or
repeatedly flushing sea otters from a haulout. Exposure to noise
capable of causing PTS is also considered take by Level A harassment.
Intermediate reactions that disrupt biologically significant
behaviors are considered Level B harassment under the MMPA. The Service
has identified the following sea otter behaviors as indicating possible
Level B take:
Swimming away at a fast pace on belly (i.e., porpoising);
Repeatedly raising the head vertically above the water to
get a better view (spyhopping) while apparently agitated or while
In the case of a pup, repeatedly spyhopping while hiding
behind and holding onto its mother's head;
Abandoning prey or feeding area;
Ceasing to nurse and/or rest (applies to dependent pups);
Ceasing to rest (applies to independent animals);
Ceasing to use movement corridors along the shoreline;
Ceasing mating behaviors;
Shifting/jostling/agitation in a raft so that the raft
Sudden diving of an entire raft;
Flushing animals off a haulout.
This list is not meant to encompass all possible behaviors; other
situations may also indicate Level B take. It is also important to note
that, depending on the duration and severity of the above-described
behaviors, such responses could constitute take by Level A harassment,
e.g., repeatedly flushing sea otters from a haulout versus a single
Direct and Indirect Effects
The reactions of wildlife to disturbance can range from short-term
behavioral changes to long-term impacts that affect survival and
reproduction. Most sea otters will respond to human disturbance with
nonlethal reactions that are similar to antipredator responses (Frid
and Dill 2002). Sea otters are susceptible to predation, particularly
from killer whales and eagles, and have a well-developed antipredator
response to perceived threats. Sea otters will swim away, dive, or hide
among rocks or kelp, and will sometimes spyhop (vertically raise its
head out of the water, presumably to look around) or splash when
threatened. Limbaugh (1961) reported that sea otters were apparently
undisturbed by the presence of a harbor seal (Phoca vitulina), but they
were quite concerned with the appearance of a California sea lion. They
demonstrated their fear by actively looking above and beneath the water
when a sea lion was swimming nearby.
Although an increase in vigilance or a flight response is
nonlethal, a tradeoff occurs between risk avoidance and energy
conservation (Frid and Dill 2002). For example, southern sea otters in
areas with heavy recreational boat traffic demonstrated changes in
behavioral time budgeting showing decreased time resting and changes in
haulout patterns and distribution (Benham 2006; Maldini et al. 2012).
In an example described by Pavez et al. (2015), South American sea
lions (Otaria byronia) visited by tourists exhibited an increase in the
state of alertness and a decrease in maternal attendance and resting
time on land, thereby potentially reducing population size. In another
example, killer whales (Orcinus orca) that lost feeding opportunities
due to boat traffic faced a substantial (18 percent) estimated decrease
in energy intake (Williams et al. 2006). Such disturbance effects can
have population-level consequences. Increased disturbance rates have
been associated with a decline in abundance of bottlenose dolphins
(Tursiops sp.) (Bejder et al. 2006; Lusseau et al. 2006).
These examples illustrate direct effects on survival and
reproductive success, but disturbances can also have indirect effects.
When disturbed by
noise, animals may respond behaviorally (e.g., escape response), as
well as physiologically (e.g., increased heart rate, hormonal response)
(Harms et al. 1997; Tempel and Gutierrez 2003). In the absence of an
apparent behavioral response, an animal exposed to noise disturbance
may still experience stress and direct energy away from fitness-
enhancing activities such as feeding and mating. The energy expense and
physiological effects could ultimately lead to reduced survival and
reproduction (Gill and Sutherland 2000; Frid and Dill 2002). Changes in
behavior from anthropogenic disturbance can also include latent
agonistic interactions between individuals (Barton et al. 1998).
Chronic stress can lead to weakened reflexes, lowered learning
responses (Welch and Welch 1970; van Polanen Petel et al. 2006),
compromised immune function, decreased body weight, and abnormal
thyroid function (Selye 1979).
The type and extent of response may be influenced by intensity of
the disturbance (Cevasco et al. 2001), the extent of previous exposure
to humans (Holcomb et al. 2009), the type of disturbance (Andersen et
al. 2012), and the age and/or sex of the individuals (Shaughnessy et
al. 2008; Holcomb et al. 2009). Despite the importance of understanding
the effects of disturbance, few controlled experiments or field
observations have been conducted on sea otters to address this topic.
Responses to Activities
The available studies of sea otter behavior suggest that sea otters
may be more resistant to the effects of sound disturbance and other
human activities than some other marine mammals. For example, at
Soberanes Point, California, Riedman (1983) examined changes in the
behavior, density, and distribution of southern sea otters that were
exposed to recorded noises associated with oil and gas activity. The
underwater sound sources were played at a level of 110 dB and a
frequency range of 50 to 20,000 Hz and included production platform
activity, drillship, helicopter, and semi-submersible sounds. Riedman
(1983) also observed the sea otters during seismic airgun shots fired
at decreasing distances from the nearshore environment (50, 20, 8, 3.8,
3, 1, and 0.5 nautical miles) at a firing rate of 4 shots per minute
and a maximum air volume of 4,070 cubic inches (in\3\). Riedman (1983)
observed no changes in the presence, density, or behavior of sea otters
as a result of underwater sounds from recordings or airguns, even at
the closest distance of 0.5 nautical miles (<1 km or 0.6 mi). However,
otters did display slight reactions to airborne engine noise. Riedman
(1983, 1984) also monitored the behavior of sea otters along the
California coast while they were exposed to a single 100-in\3\ airgun
and a 4,089-in\3\ airgun array. Sea otters did not respond noticeably
to the single airgun, and no disturbance reactions were evident when
the airgun array was as close as 0.9 km (0.6 mi).
Sea otters spend from 30 to 80 percent of their time each day at
the surface of the water resting and grooming (Riedman 1983, 1984;
Bodkin et al. 2004; Wolt et al. 2012). While at the surface, turbulence
from wind and waves attenuate noise more quickly than in deeper water,
reducing potential noise exposure (Greene and Richardson 1988;
Richardson et al. 1995). Additionally, turbulence at the water's
surface limits the transference of sound from water to air. A sea otter
with its head above water will be exposed to only a small fraction of
the sound energy travelling through the water beneath it. Thus, the
amount of total time spent at the surface may help limit sea otters'
exposure during noise-generating operations.
Sea otters do not rely on sound to orient themselves, locate prey,
or communicate underwater. Sea otters use sound for communication in
air (especially mothers and pups; McShane et al. 1995) and may avoid
predators by monitoring underwater sound. Davis et al. (1987)
documented sea otters retreating from simulated killer whale
vocalizations. Otters are not known to vocalize underwater and do not
echolocate; therefore, masking of communications by anthropogenic sound
is less of a concern than for other marine mammals.
Sea otters generally show a high degree of tolerance to noise. In
another study using prerecorded sounds, Davis et al. (1988) exposed
both northern sea otters in Simpson Bay, Alaska, and southern sea
otters in Morro Bay, California, to a variety of airborne and
underwater sounds, including a warble tone, sea otter pup calls, killer
whale calls, airhorns, and an underwater noise harassment system
designed to drive marine mammals away from crude oil spills. The sounds
were projected at a variety of frequencies, decibel levels, and
intervals. The authors noted that certain noises could cause a startle
response and result in dispersal. However, the disturbance effects were
limited in range (no responses were observed for otters approximately
100-200 m (328-656 ft) from the source of the stimuli), and habituation
to the stimuli was generally very quick (within hours or, at most, 3 to
Southern sea otters in an area with frequent railroad noise
appeared to be relatively undisturbed by pile-driving activities, many
showing no response and generally reacting more strongly to passing
vessels than to the sounds of pile-driving equipment (ESNERR 2011; ESA
2016). Additionally, many of the otters who displayed a reaction
behavior during pile driving did so while their heads were above the
surface of the water, suggesting that airborne noise was as important
as, and possibly more important than underwater noise in prompting the
animals' reactions. When sea otters have displayed behavioral reactions
in response to noise, these responses were often short-lived; the
otters resumed normal activities soon after a new sound was introduced
(Davis et al. 1987, 1988).
Stimuli from shoreline construction activities, aircraft, and
vessel traffic, including noise, are likely to cause some level of
disturbance. Populations of sea otters in Alaska have been known to
avoid areas with heavy boat traffic but return to those same areas
during seasons with less traffic (Garshelis and Garshelis 1984). Sea
otters in Alaska have shown signs of disturbance (escape behaviors) in
response to the presence and approach of survey vessels, including:
otters diving and/or actively swimming away from a boat; hauled-out
otters entering the water; and groups of otters disbanding and swimming
in multiple different directions (Udevitz et al. 1995).
In Cook Inlet, otters were observed riding the tides past a new
offshore drilling platform while drilling was being conducted. Otters
drifting on a trajectory that would have taken them within 500 m (0.3
mi) of the rig tended to swim to change their angle of drift to avoid a
close approach, although noise levels from the work were near the
ambient level of underwater noise (BlueCrest 2013).
Sea otter behavior is suggestive of a dynamic response to
disturbance, influenced by the intensity and duration of the source.
Otters initially abandon areas when disturbed and return when the
disturbance ceases. Groups of sea otters in two locations in California
showed markedly different responses to kayakers approaching to within
specific distances, suggesting a different level of tolerance between
the groups (Gunvalson 2011). Benham (2006) found evidence that the
otters exposed to high levels of recreational activity may have become
more tolerant than individuals in less-disturbed areas.
Some individual otters will habituate to the presence of project
vessels, noise, and activity. Sea otters often seem quite tolerant of
boats or humans nearby (e.g., Calkins 1979). Sea otters off the
California coast showed only mild interest in boats passing within
hundreds of meters and appeared to have habituated to boat traffic
(Riedman 1983; Curland 1997). Boat traffic, commercial and
recreational, is common in Cook Inlet. However, there are seasonal
(i.e., temporal) and spatial components to vessel traffic. Both
recreational and commercial vessel traffic in Kachemak Bay is much
higher than in western Cook Inlet, and all traffic is much higher in
summer than in other months. Some sea otters in the area of activity
are likely to have already become habituated to vessel traffic and
noise caused by vessels, whereas for others, the specified activities
will be a novel experience and will elicit a more intense response.
Some degree of disturbance is also possible from unmitigated
aircraft activities. Individual sea otters in Cook Inlet will show a
range of responses to noise from low-flying aircraft. Some may abandon
the flightpath area and return when the disturbance has ceased. Based
on the observed movement patterns of wild sea otters (i.e., Lensink
1962; Kenyon 1969, 1981; Garshelis and Garshelis 1984; Riedman and
Estes 1990; Tinker and Estes 1996; and others), we expect that some
individuals, independent juveniles, for example, will respond to the
project activities by dispersing to areas of suitable habitat nearby,
while others, especially breeding-age adult males, will not be
displaced by overflights. Mitigation measures will stipulate a minimum
of 305 m (1,000 ft) flight altitude to minimize harassment of otters.
Given the observed responses of sea otters to sources of
disturbance, it is likely that some degree of take by harassment will
occur due to underwater noise stimuli associated with the specified
activities. Some otters will likely show startle responses, change
direction of travel, disperse from the area, or dive. Sea otters
reacting to project activities may expend energy and divert time and
attention from biologically important behaviors, such as feeding. Some
effects may be undetectable in observations of behavior, especially the
physiological effects of chronic and cumulative noise exposure. Air and
vessel traffic, commercial and recreational, is routine in Cook Inlet.
Construction activities are common. Some sea otters in the area of
activity may become habituated to the project noise or may already be
habituated to noise due to previous and ongoing exposure to frequent
air traffic and other activities in the area and will have little, if
any, reaction to project activities.
Mitigation and Monitoring
When the Service issues an ITR, we specify means for effecting the
least practicable adverse impact on sea otters and their habitat,
paying particular attention to habitat areas of significance, and on
the availability of sea otters for taking for subsistence uses by
coastal-dwelling Alaska Natives. These measures are stipulated in Sec.
In evaluating what mitigation measures are appropriate to ensure
the least practicable adverse impact on species or stocks and their
habitat, as well as subsistence uses, we considered the manner in
which, and the degree to which, the successful implementation of the
measures are expected to reduce impacts to sea otters, stocks, and
their habitat, as well as subsistence uses. We considered the nature of
the potential adverse impact being mitigated (likelihood, scope,
range), the likelihood the measures will be effective, and the
likelihood the measures will be implemented. We also considered the
practicability of the measures for applicant implementation (e.g.,
cost, impact on operations).
To reduce the potential for disturbance from noise associated with
the activities, the following mitigation measures are required:
Development of marine mammal monitoring and mitigation
Establishment of an exclusion zone (EZ) and safety zone
(SZ) during noise-generating work;
Visual mitigation monitoring by designated protected
species observers (PSOs);
Site clearance before startup;
Ramp-up procedures; and
Vessel strike avoidance measures.
This ITR establishes the process for evaluating specific activities
in specific project areas and determining the appropriate mitigation
measures to be included in an LOA. A marine mammal mitigation and
monitoring plan (4MP) is required for all LOAs. The 4MP identifies the
specific avoidance and minimization measures an applicant will take to
reduce effects to otters. It describes the project in detail, assesses
the effects, identifies effective means to avoid effects, and describes
specific methods for limiting effects when they cannot be avoided.
During ``noise-generating work'' (work that creates underwater
sound louder than 160 dB and within the frequency hearing range of sea
otters), an applicant will establish and monitor an EZ. The EZ is
defined as the area surrounding a sound source in which all operations
must be shut down in the event a sea otter enters or is about to enter
this zone based on distances to Level A thresholds. Any otter detected
within this zone will be exposed to sound levels likely to cause take
by Level A harassment. The SZ is an area larger than the EZ and is
defined as the area in which otters may experience noise above the
Level B exposure threshold. Sea otters observed inside the SZ are
likely to be disturbed by underwater noise, and each otter within the
SZ will be counted as one Level B take. In the event a sea otter is in
or about to enter the zone, operations will be powered down, when
practicable, to minimize take. Radii of each SZ and EZ will be
specified in each LOA issued under this ITR. The methodology for
calculation of the radii will be described in each LOA and is
identified in Sec. 18.137 Mitigation. Sound source levels will be
monitored and evaluated in the field prior to conducting 2D and 3D
seismic surveys. This on-site sound source verification (SSV) testing
will be used to determine the size of the SZ and EZ for these
activities. A minimum 10-m (33-ft) shutdown zone will be observed for
all in-water construction and heavy machinery.
PSOs will be stationed on the source vessel or at a suitable
vantage point with maximum view of the SZ and EZ. The PSOs will
determine that the EZ is clear of sea otters prior to the start of
daily activities or if activities have been stopped for longer than a
30-minute period. The PSOs will ensure that no sea otters are observed
in the EZ for a period of 30 minutes prior to work commencing.
For the 2D survey, PSOs will be stationed on the source vessel
during all seismic operations and geohazard surveys when the sub-bottom
profilers are used. Because of the proximity to land, PSOs may also be
stationed on land to augment the viewing area. For the 3D survey, PSOs
will be stationed on at least two of the project vessels: The source
vessel and the chase vessel. For the vertical seismic profiling, PSOs
will be stationed on the drilling rig. For geohazard surveys, PSOs will
be stationed on the survey vessel. The viewing area may be augmented by
placing PSOs on a vessel specifically for mitigation purposes or using
an unmanned aircraft system (drone). If drones will be used in areas
otters, mitigation measures will be required to ensure drone use does
not disturb otters. These measures may include maintaining a minimum
altitude and horizontal distance no less than 100 m away from otters,
conducting continuous visual monitoring by PSOs, and ceasing activities
in response to sea otter behaviors indicating any reaction to drones.
A power-down procedure will be in place during seismic work. It
will provide the option of reducing the number of airguns in use, which
reduces the EZ or SZ radius. Alternatively, a shutdown procedure may be
necessary, during which all airgun activity is suspended immediately.
During a power-down, a single airgun (``mitigation gun'') may be
operated, maintaining a sound source with a much-reduced EZ. If a sea
otter is detected outside of either the SZ or EZ but is likely to enter
that zone, the airguns may be powered down before the animal is within
the radius, as an alternative to a complete shutdown. Likewise, if a
sea otter is already within the SZ when first detected, the airguns may
be powered down if this is a reasonable alternative to an immediate
shutdown. If a sea otter is already within the EZ when first detected,
the airguns will be shut down immediately. All power-down events will
be at the discretion of the operator in cooperation with the PSOs. The
applicant has determined that it is not practicable to power down in
response to all sea otters within the SZ, and that to do so would
incapacitate the 2D and 3D seismic operations. Because power-down
events will be discretionary, all otters within the SZ will be assumed
to experience Level B take regardless of whether a power-down is
conducted. Although there is no calculated reduction of take estimated
for this mitigation measure due to uncertainty in its application, it
is expected that some unquantified benefits to sea otters will be
realized whenever the operator powers down to reduce or avoid sea otter
A shutdown will occur when all underwater sound generation that is
louder than 160 dB and within the frequency hearing range of sea otters
is suspended. The sound source will be shut down completely if a sea
otter approaches the EZ or appears to be in distress due to the noise-
generating work. The shutdown procedure will be accomplished as soon as
practicable upon the determination that a sea otter is either in or
about to enter the EZ, and generally within several seconds. Following
a shutdown, noise-generating work will not resume until the sea otter
has cleared the EZ. Any shutdown due to a sea otter sighting within the
EZ must be followed by a 30-minute all-clear period and then a
standard, full ramp-up. Any shutdown for other reasons resulting in the
cessation of the sound source for a period greater than 30 minutes must
also be followed by full ramp-up procedures.
A ``ramp-up'' procedure will be in place to gradually increase
sound volume at a specified rate. Ramp-up is used at the start of
airgun operations, including after a power-down, shutdown, or any
period greater than 10 minutes in duration without airgun operations.
The rate of ramp-up will be no more than 6 dB per 5-minute period.
Ramp-up will begin with the smallest gun in the array that is being
used for all airgun array configurations. The ramp-up procedure for
pipe/pile driving involves initially starting with soft strikes or a
reduced level of energy. If the complete EZ has not been visible for at
least 30 minutes prior to the start of operations, operation of a
mitigation gun may be required during the interruption of seismic
survey operations prior to commencing ramp-up procedures. It will not
be permissible to ramp up the full array from a complete shutdown in
thick fog or at other times when the outer part of the Level A EZ is
not visible. Ramp-up of the airguns will not be initiated if a sea
otter is sighted within the EZ at any time.
A speed or course alteration is appropriate if a sea otter is
detected outside the EZ and, based on its position and relative motion,
is likely to enter the EZ, and a vessel's speed and/or direct course
may, when practical and safe, be changed. This technique can be used in
coordination with a power-down procedure. The sea otter activities and
movements relative to the seismic and support vessels will be closely
monitored to ensure that the sea otter does not approach within the EZ.
If the sea otter appears likely to enter the EZ, further mitigative
actions will be taken, i.e., further course alterations, power-down, or
shutdown of the airguns.
This ITR establishes the stakeholder engagement process that the
applicant is required to undertake in order to obtain an LOA for
incidental take of sea otters. This process is an ongoing collaborative
process between the applicant, the Service, and subsistence users of
sea otters. Stakeholder engagement efforts for the specified activities
have been ongoing since mid-2018 and have indicated that a plan of
cooperation (POC) is necessary for the Hilcorp and Harvest 3D seismic
work. The POC must include a schedule for meeting with the affected
communities, both prior to and while conducting the activities, a plan
for resolving any conflicts, suggested means for resolving conflict,
and process for notifying the communities of any changes in the
The measures described here and required in Sec. 18.137 through
Sec. 18.140, Mitigation, Monitoring, Reporting Requirements, and
Measures to Reduce Impacts to Subsistence Users, are those determined
to achieve the least practicable adverse impact to northern sea otters
and their availability for subsistence use. These mitigation measures
were evaluated against a suite of possible alternatives to determine
whether they would effect the least practicable adverse impact on the
species, their habitat, and the availability of the species for
Alternative mitigation measures were evaluated but ultimately
rejected as either not feasible, not practicable, not likely to be
implemented effectively, or no more likely to be successful in reducing
the impacts of the applicant's project. We considered requiring work to
be paused or stopped to prevent exposure of northern sea otters to
levels of noise exceeding a 160-dB Level B take threshold. The
distances to the 160-dB sound isopleths for several of the specified
activities are greater than 1 km (0.6 mi). Avoiding all northern sea
otters within these distances would require work to shut down or power
down for prolonged and repeated periods, which the applicant has
determined would incapacitate the project. Therefore, this is not a
practicable mitigation measure.
The Service considered alternative mitigation measures based on
observing and interpreting northern sea otter behaviors for preventing
Level B harassment. Presently, mitigation protocols use sound exposure
to predict behavioral responses rather than observing behavior
directly. While direct observation of injury or the disruption of a
behavioral pattern is the definitive criteria for identifying take once
it has occurred, at present there is insufficient data to develop
observation-based criteria for preventing harassment. Thus, monitoring
of behavioral responses is useful for identifying take after it occurs,
but not for preventing or mitigating it. As such, effectiveness of
monitoring protocols based on behavior cannot be ascertained.
Therefore, behavior-based mitigation was not a feasible alternative.
We considered requiring the use of alternative technologies such as
marine vibroseis to reduce or eliminate the
need for seismic airguns. Hilcorp and Harvest have requested takes of
marine mammals incidental to the seismic survey operations described in
the petition, which identified airgun arrays as the preferred data
acquisition tool. It would be inappropriate for the Service to require
the applicant to change the specified activity unless it was necessary
to make the findings established for issuance of incidental take under
the MMPA or necessary for achieving the least practicable adverse
impact to the marine mammal stock. Currently, no alternative technology
scaled for industrial use is reliable enough to meet the environmental
challenges of operating in Cook Inlet. Many prototypes are currently in
development and may ultimately become important for achieving the least
practicable level of effect on marine mammals, but none of these
technologies are currently practicable for use on a large scale in Cook
The option of designating seasonal exclusion areas within the
specified geographic area was considered. However, no activities are
planned in areas of Cook Inlet known to provide important habitat.
Kachemak Bay, Kamishak Bay, and the designated critical habitat along
the western shoreline of LCI and MCI are known areas of important
habitat, but have not been identified as the target location of any
planned activity in this rule. There is some information that suggests
that the east coast of Cook Inlet along the Kenai Peninsula may be used
seasonally by sea otters in late summer (BlueCrest 2013). Restrictions
on seismic survey operations in this area during this time period might
reduce the probability of disturbance of sea otters. However, there is
currently insufficient information to support a seasonal restriction in
eastern Cook Inlet. Little is known about the extent or duration of the
use of the area by sea otters or what life-history functions the area
supports. The benefit such a designation might offer is entirely
unknown and, until additional information is available, remains
Compensatory mitigation was considered. Some environmental laws
allow compensatory mitigation, such as habitat restoration projects, to
be used by the applicant to offset effects of the project activities
that cannot otherwise be avoided. The Service is issuing an
authorization for incidental take of sea otters under the MMPA. The
MMPA requires that impacts be reduced to the least practicable level,
but does not require offsets. The Service must consider the
practicability of implementation of measures to reduce impacts, as well
as proven or likely effectiveness of those measures. The impacts to sea
otters and their habitat in Cook Inlet will be primarily acoustic and
temporary in nature. We are not currently aware of literature
demonstrating the effectiveness of habitat restoration for mitigating
the effects of underwater noise. Additionally, we are not aware of any
practicable habitat improvement projects in Cook Inlet that would have
demonstrable benefits for the affected stocks.
In order to issue an LOA for an activity, section 101(a)(5)(A) of
the MMPA states that the Service must set forth ``requirements
pertaining to the monitoring and reporting of such taking.'' The
Service's implementing regulations at Sec. 18.27(d)(vii) stipulate
that requests for authorizations must include the suggested means of
accomplishing the necessary monitoring and reporting. Effective
reporting is critical to compliance as well as ensuring that the most
value is obtained from the required monitoring. The applicant will
employ PSOs to conduct visual project monitoring. SSV monitoring will
be conducted to document sound levels produced by the work. During 2D
and 3D seismic surveys, Hilcorp and Harvest have agreed to conduct
aerial overflights for avoidance of other marine mammal species, which
will improve monitoring of sea otters. Additional monitoring and
reporting requirements are at Sec. 18.138 Monitoring and Sec. 18.139
Alternative monitoring measures were considered, but they were not
incorporated in this rule. Passive acoustic monitoring is appropriate
for some species of marine mammals but is not indicated for sea otters,
which are not known to vocalize extensively underwater. Visual
monitoring during all times of day and night was rejected because
limited visibility during periods of darkness would prevent the
detection of animals. Thermal monitoring or monitoring of sea otters
with unmanned aircraft systems (drones) has not yet been fully tested
and evaluated for use in Cook Inlet, but may prove useful in the
future. Requiring visual observation and PSO monitoring of 100 percent
of all spatial areas within the 160-dB ensonification area was also
considered, but for 2D and 3D seismic surveys in particular, this was
not expected to be achievable. We instead accounted for all sea otter
exposures to 160 dB or greater in our estimation of take, and we did
not reduce this number to attempt to account for some proportion of the
total that might be avoided when detected by PSO monitoring.
Estimated Incidental Take
This section provides the number of incidental takes estimated to
occur because of the planned activities. The number of takes were
analyzed to make the required small numbers and negligible impact
Estimating Exposure Rates
The Service anticipates that incidental take of sea otters may
occur during the project activities in Cook Inlet. Noise, aircraft,
vessels, and human activities could temporarily interrupt feeding,
resting, and movement patterns. Elevated underwater noise levels from
seismic surveys may cause short-term, nonlethal, but biologically
significant changes in behavior that the Service considers harassment.
Pile-driving and other construction activities along the shoreline may
have similar effects and could cause behavioral disturbance leading to
take. Harassment (Level A or B) is the only type of take expected to
result from these activities; no lethal take is expected.
The number of animals affected will be determined by the
distribution of animals and their location in proximity to the project
work. Although we cannot predict the outcome of each encounter, it is
possible to consider the most likely reactions, given observed
responses of sea otters to various stimuli.
Sound exposure criteria provide the best available proxy for
estimation of exposure to harassment. The behavioral response of sea
otters to shoreline construction and vessel activities is related to
the distance between the activity and the animals. Underwater sound is
generated in tandem with other airborne visual, olfactory, or auditory
signals from the specified activities, and travels much farther.
Therefore, estimating exposure to underwater sound can be used to
estimate the take from project activities.
No separate exposure evaluation was done for activities that do not
generate underwater sound. Nearly all of the planned activities that
may disturb sea otters will occur simultaneously with in-water
activities that do generate sound. For example, operation of heavy
equipment along the shoreline will facilitate underwater pile driving.
The otters affected by the equipment operations are the same as those
affected by the pile driving. Sound exposure and behavioral
disturbances are accumulated over a 24-hour period, resulting in
estimation of one exposure from all in-water sources rather than one
each from equipment operations
and pile-driving noise. Aircraft support activities will be conducted
without a corresponding underwater sound component, but no take is
expected from this source of disturbance; see ``Airborne Sounds.''
To estimate the exposure of sea otters to take, we first calculated
the number of otters in Cook Inlet that occur within the project area.
The number of otters was calculated from density multiplied by project
area. Density was estimated according to region in Cook Inlet.
Density data for Kamishak and the East side of Cook Inlet along the
shore of the Kenai Peninsula was derived from aerial surveys conducted
in May 2017 (Garlich-Miller et al. 2018). Surveys were not conducted
for central Cook Inlet in 2017, and the 2017 surveys for western Cook
Inlet north of Kamishak did not yield useful results. Therefore, the
density for those regions was derived from the 2002 surveys conducted
by Bodkin et al. (2003) and corrected for population growth
proportional to the growth rate of Cook Inlet as a whole, as determined
from comparison of the 2002 and 2017 surveys. Density values (in otters
per km\2\) were 1.7 in East Cook Inlet (excluding Kachemak Bay and the
outer Coast of Kenai Peninsula south and east of Seldovia), 3.53 in
Kamishak Bay, and 0.026 in West and Central Cook Inlet. There are no
density data for sea otters in the MCI region north of approximately
60[deg]14' N (the latitude of Clam Gulch), and otters are uncommon
north of about 60[deg]24' N. Therefore, densities north of Clam Gulch
were conservatively assumed to equal the 2002 mid-Cook Inlet survey
region density of 0.01 per km\2\ from Bodkin et al. (2003).
The geographic area of activity covers approximately 11,084 km\2\
(4,280 mi\2\) in Cook Inlet. Of this area, 1,572 km\2\ (607 mi\2\) is
in East Cook Inlet, 725 km\2\ (280 mi\2\) in Kamishak Bay, 4,341 km\2\
(1,676 mi\2\) in West and Central Cook Inlet, and 4,445 km\2\ (1,716
mi\2\) in Cook Inlet north of the normal range of sea otters. The total
number of otters within the project area was calculated to be 5,389
otters ((1,572 x 1.7) + (725 x 3.53) + (4,341 x 0.026) + (4,445 x 0.01)
Not all otters in the project area will be exposed to noise levels
capable of causing take from project activities. Many activities
associated with oil and gas exploration, development, production, and
transportation may result in underwater sounds that do not meet Levels
A and B acoustic harassment criteria. The acoustic characteristics of
the different project activities are described in table 3. Only those
specific activities with the likelihood of meeting the acoustic
exposure criteria and occurring in the normal range of sea otters were
evaluated for estimation of potential Levels A and B harassment.
Specifically, Hilcorp and Harvest's activities include 2D and 3D
seismic surveys, vibratory driving of sheet piles at the Iniskin
Peninsula causeway in Chinitna Bay, sub-bottom profilers used in high-
and low-resolution geohazard surveys, drive-pipe installation, vertical
seismic profiling, plug-and-abandon activities, and use of water jets
during routine maintenance. AGDC's activities include pile driving and
The number of exposures to underwater sound levels capable of
causing take by Level A harassment from specific project elements was
estimated using the thresholds recommended by NMFS (2018a,b) for
otariid pinnipeds (232 dB peak and 203 dB SELcum). For Level
B harassment we used a 160-dB threshold. We multiplied the estimated
area of ensonification (km\2\), by the density of sea otters in that
area (number (#) of otters per km\2\) to estimate the number of otters
in the ensonified area. This value was then multiplied by the maximum
duration of the activity (# of days) over the course of the 5-year
regulatory period to get the total number of exposures to sound above
the thresholds for take.
Predicting Behavioral Response Rates
Although we cannot predict the outcome of each encounter between a
sea otter and the equipment and vessels used for the planned
activities, it is possible to consider the most likely reactions. Sea
otters do not appear highly reactive to underwater sounds, but the
presence of vessels may elicit stronger behavioral responses (see
Responses to Activities). Whether an individual animal responds
behaviorally to the presence of vessels and equipment is dependent upon
several variables, including the activity of the animal prior to
stimulus, whether the animal is habituated to similar disturbances,
whether the animal is in a state of heightened awareness due to recent
disturbances or the presence of predators, group size, the presence of
pups, and the temperament of the individual animals. We assumed all
animals exposed to underwater sound levels that meet the acoustic
exposure criteria shown in table 5 would experience Level A or Level B
The total take of sea otters from these oil and gas activities in
Cook Inlet was estimated by calculating the number of otters in the
ensonified area during the full duration (the maximum number of days)
of each project activity. After publication of the proposed ITR in the
Federal Register, the applicant provided updates and minor
modifications to their project plans. Changes included an increase in
the 3D seismic survey line length from 74 km (46 mi) to 127 km (79 mi),
an adjustment to account for the proportion of line length actively
surveyed with the airgun array each day, use of a boomer rather than
chirper sub-bottom profiler, and changes to the total duration (number
of days) of pile driving and vertical seismic profiling in TB and LCI.
The changes are reflected in the analysis presented here. Details of
the project activities and calculations of take are included in the
applicant's updated petition (June 2019) available at
www.regulations.gov under docket number FWS-R7-ES-2019-0012. Methods
used for calculating take did not change, but the resulting estimates
have been updated. The total take increased from 1,666 to 1,687.
Distances to Thresholds
To calculate the ensonified area, we first estimated the distances
that underwater sound will travel before attenuating to levels below
thresholds for take by Level A and Level B harassment. The distances to
the Level A thresholds were calculated using the NMFS Acoustical
Guidance Spreadsheets (NMFS 2018b) using thresholds for otariid
pinnipeds as a proxy for sea otters. Distances to the 160-dB Level B
threshold were calculated using a practical spreading transmission loss
model (15 LogR). The only exceptions to the use of the practical
spreading model were made when data was available from a site-specific
sound source verification of substantially similar equipment used and
powered in a similar manner to that proposed by the applicant.
Model estimates incorporated operational and environmental
parameters for each activity. For example, sound levels at the source
are shown in table 3, and characteristics of the sound produced are
shown in table 6. Weighting factor adjustments were used for SEL (sound
exposure level) calculations based on NMFS Technical Guidance (2018b).
Operational parameters were estimated from the updated description of
The distances to the modelled Level A and Level B thresholds are
shown in table 7. Each estimate represents the radial distance away
from the sound source within which a sea otter exposed to the sound of
the activity is expected
to experience take by Level A or Level B harassment.
Table 6--Assumptions Used in Calculating Distances to Level A and Level B Thresholds
Activity Type of source Source level \1\ WFA \2\ Source velocity Pulse duration Repetition rate Duration per day
2D/3D seismic.................... Mobile impulsive.... 217 @100 m (185 dBSEL @100 m). 1 kHz............. 2.05 m/s.......... N/A............... every 6 s............. 3D: 10 hrs/day.
2D: 2 hrs/day.
Sub bottom profiler.............. Mobile impulsive.... 212 @1 m...................... 4 kHz............. 2.05 m/s.......... 0.02 s............ every 0.30 s.......... N/A.
Impact pile driving.............. Stationary impulsive <=195 @10 m................... 2 kHz............. N/A............... N/A............... 1,560 strikes/hr...... <=5.5 hrs/day.
Pipe driving..................... Stationary impulsive <=195 @55 m................... 2 kHz............. N/A............... 0.02 s............ <=1,560 strikes/hr.... <=4.8 hrs/day.
Vertical seismic profiling....... Stationary impulsive 227 @1 m...................... 1 kHz............. N/A............... 0.02 s............ every 6 s............. 4 hrs/day.
Impact sheet piling.............. Stationary impulsive 190 @10 m..................... 2 kHz............. N/A............... 0.02 s............ 1,560 strikes/hr...... 3 hrs/day.
Vibratory sheet piling........... Stationary non- 160 @10 m..................... 2.5 kHz........... N/A............... N/A............... N/A................... <=4.8.
Water jet........................ Stationary non- 176 @1 m...................... 2 kHz............. N/A............... N/A............... N/A................... 0.5 hrs/day.
Anchor handling.................. Mobile non-impulsive 179 @1 m...................... 1.5 kHz........... 1.54 m/s.......... N/A............... N/A................... 3 hrs/day.
\1\ Source level is given in dBrms, unless otherwise indicated, as measured at the given distance from the source in meters.
WFA = Weighting Factor Adjustment, SEL = sound exposure level.
Table 7--Calculated Distance in Meters (m) to Level A and Level B Thresholds
Level A--NMFS otariid Level B
Activity Impulsive Non-impulsive Both
232 dB peak 203 dB SEL 219 dB SEL 160 dB rms
2D/3D seismic................................... 10 1.32 N/A 7,330
Sub-bottom profiler............................. 0.05 1 N/A 2,929
Pipe driving, Chinitna Bay...................... 0.19 39.48 N/A 1,630
VSP............................................. 0.46 284.84 N/A 2,470
Vibratory sheet pile driving.................... N/A N/A 0.46 10
Water jet....................................... N/A N/A 0.54 11.66
18- and 24-inch pipe, impact.................... 0.22 50.53 N/A 1,874.85
48- and 60-inch pipe, impact.................... 0.34 147.99 N/A 2,154.43
all sizes pipe, vibratory....................... N/A N/A 3.30 46.42
Sheet pile, impact.............................. 0.16 68.69 NA 1,000
Sheet pile, vibratory........................... N/A N/A 0.71 10
Anchor handling................................. N/A N/A 0.00 0.00
SEL = sound exposure level.
Area and Duration
The area of ensonification is the area in which an animal exposed
to underwater sound is expected to experience take from Level A or
Level B harassment based on the distance to the Level A and Level B
thresholds. The area of a circle (A = [pi]r\2\) where r is the distance
to the Level A or Level B threshold was used to calculate the area of
ensonification for impulsive stationary sources (pipe driving, vertical
seismic profiling), non-impulsive stationary sources (water jets,
vibratory pile driving). For impulsive mobile sources (2D/3D seismic,
sub-bottom profiler), the radial area was then multiplied by the
distance of the line to be surveyed each day to get the total area of
ensonification. Otters spend most of their time at the water's surface
or below their last surface location, so a circle with the sound source
at its center is a reasonable representation of the ensonified area.
For shoreline activities, the area of the circle is divided by two to
remove the area that lies above the shoreline. The daily area of
ensonification was then multiplied by the duration of the activity in
number of days and the density of otters in the applicable region of
Cook Inlet to estimate the number of otters that might be taken. In
total, 1,687 instances of take are expected. The total Level A take of
sea otters in Cook Inlet over the 5-year course of this ITR is
anticipated to be 3. The total number of takes from each project
activity is presented in table 8.
For some projects, like the 3D seismic survey, the design of the
project is well developed; therefore, the duration is well defined.
However, for other projects, the duration is not well developed, such
as activities around the LCI well sites. In each case, the calculations
are based on the applicant's best forecast of activities in the 5-year
ITR period. The assumptions regarding duration of these activities are
presented in the applicant's updated petition (June 2019). The
durations used for each activity are provided in table 8. For Level B
take, we assumed one take per otter per day regardless of duration of
work within a day. The resulting estimate of the total number of Level
B takes expected from planned oil and gas activities in Cook Inlet from
2019 through the date 5 years from the effective date of the final rule
The proposed ITR included calculation of the numbers of individual
otters taken. Those estimates have been removed from this ITR because
the methodology used to calculate take of individuals led to
substantial uncertainty in the accuracy of the estimates. We here rely
instead on the number of takes to determine the likely effects to the
stock. The total number of takes is expected to be higher than the
number of otters taken because, for example, a resident otter may be
taken on each day of noise-generating activity.
Table 8--Estimate of Total Take for Each Activity
Level A Level B
Applicant Activity Density (#/ Duration Impulsive Non-impulsive
km\2\) (days) ---------------------------------------------------------------
232 pk 203 SEL 219 SEL 160 rms
Hilcorp/Harvest Alaska............ 2D seismic.......... 1.705 10.000 1.023 0.135 .............. 749.859
3D seismic.......... 0.026 60 1.155 0.152 .............. 846.896
Vibratory sheet pile 0.026 20 .............. .............. 0.000 0.000
Sub-bottom profiler- 0.026 28 0.001 0.014 .............. 46.291
Sub-bottom profiler- 0.010 7 0.000 0.001 .............. 4.740
Sub-bottom profiler- 0.010 14 0.000 0.003 .............. 9.479
Sub-bottom profiler- 0.010 3 0.000 0.000 .............. 2.031
Pipe driving-LCI.... 0.026 12 0.000 0.002 .............. 2.604
Pipe driving-TB..... 0.010 6 0.000 0.000 .............. 0.501
VSP-LCI............. 0.026 8 0.000 0.040 .............. 3.987
VSP-TB.............. 0.010 4 0.000 0.008 .............. 0.767
AGDC.............................. Product Loading 0.010 .............. .............. .............. .............. ..............
48-inch impact...... .............. 56 0.000 0.019 .............. 4.083
60-inch impact...... 0.010 106 0.000 0.036 .............. 7.728
Temporary MOF....... 0.010 .............. .............. .............. .............. ..............
18- and 24-inch .............. 301 .............. .............. 0.000 0.010
18- and 24-inch 0.010 7 0.000 0.000 .............. 0.510
48-inch impact...... 0.010 7 0.000 0.002 .............. 0.510
60-inch vibratory... 0.010 11 .............. .............. 0.000 0.000
sheet vibratory..... 0.010 66 .............. .............. 0.000 0.000
Mainline MOF........ 0.010 .............. .............. .............. .............. ..............
sheet vibratory..... .............. 7 .............. .............. 0.000 0.000
sheet impact........ 0.010 7 0.000 0.001 .............. 0.110
Anchor handling..... 0.010 76 .............. .............. 0.000 0.000
Total......................... .................... .............. .............. 2.18 0.42 0.00 1,683.108
SEL = sound exposure level, LCI = Lower Cook Inlet, MCI = Middle Cook Inlet, NCI = North Cook Inlet, TB = Trading Bay, MOF = material offloading
facility, VSP = vertical seismic profiling.
The number of takes from each stock was estimated by categorizing
each activity by its location relative to sea otter stock boundaries.
Some activities will occur within both the southcentral Alaska and
southwest Alaska stock boundaries. For these, take was assigned in
proportion to the area of the activity within each stock region. Table
9 shows the activities in relation to the sea otter stock boundaries as
they were assigned for this analysis. The total number of takes of sea
otters from the southwest Alaska stock is 418. The take number from the
southcentral Alaska stock is 1,269.
The total number of takes by Level A harassment is estimated to be
2.6. When the total take from each activity (table 8) is multiplied by
the proportion of that activity occurring within each stock boundary
(table 9), the sum of take is 0.6 and 2 within the southwest Alaska and
southcentral Alaska stocks, respectively. Because the number of takes
from the southwest Alaska stock is 0.6, and take cannot occur unless it
affects an animal, we rounded the number of takes from the southwest
Alaska stock from 0.6 to 1. The total take is summarized in table 10.
Table 9--Percent of Each Activity Occurring Within Each Stock Boundary
Applicant Activity Alaska stock Alaska stock
Hilcorp & Harvest Alaska...................... 2D seismic...................... .............. 100
3D seismic...................... 44 56
Vibratory sheet pile driving.... 100 ..............
Sub-bottom profiler--LCI........ 44 56
Sub-bottom profiler--NCI........ 100 ..............
Sub-bottom profiler--TB......... 100 ..............
Sub-bottom profiler--MCI........ 100 ..............
Pipe driving--LCI............... 50 50
Pipe driving--TB................ 100 ..............
VSP--LCI........................ 50 50
VSP--TB......................... 100 ..............
Hydraulic grinder............... 100 ..............
Water jet....................... 100 ..............
AGDC.......................................... Product Loading Facility
48-inch impact............... .............. 100
60-inch impact............... .............. 100
18-inch vibratory............ .............. 100
24-inch impact............... .............. 100
48-inch impact............... .............. 100
60-inch vibratory............ .............. 100
sheet vibratory.............. .............. 100
sheet vibratory.............. .............. 100
sheet impact................. .............. 100
Anchor handling.............. 50 50
LCI = Lower Cook Inlet, MCI = Middle Cook Inlet, NCI = North Cook Inlet, TB = Trading Bay, MOF = material
Table 10--Summary of Estimates of Sea Otter Take by Level A and Level B Harassment and Stock
Type Unit of take Alaska stock Alaska stock Sum
Level A............................... Number of takes......... 1 2 3
Level B............................... Number of takes......... 417 1,267 1,684
Total............................. Number of takes......... 418 1,269 1,687
Annual Estimates of Take
The estimates of exposures by activity and location discussed in
the previous section are not representative of the estimated exposures
per year (i.e., annual takes). It is difficult to characterize each
year accurately because many of the activities are progressive (i.e.,
they depend on results and/or completion of the previous activity).
This results in much uncertainty in the timing, duration, and complete
scope of work. Each year, each applicant will submit an application for
an LOA with the specific details of the planned work for that year and
estimated take numbers. Table 11 summarizes the activities according to
a scenario presented in the applicant's updated petition (June 2019).
This scenario combines the most realistic progression by Hilcorp and
Harvest with an optimistic scenario for AGDC. In the first season,
Hilcorp and Harvest plan to conduct 3D seismic surveys. In the second
season, in LCI they plan to conduct activities for one well; in MCI,
they plan to conduct plugging and abandonment activities in the NCI and
two wells in the TB area. In the third season, activities include
drilling two wells in LCI. The final well in LCI is planned for the
The timing of AGDC's activities will depend on final authorizations
and funding and may begin in 2020 rather than 2019. Season 1 will be
the first year of project work regardless of year, followed by season 2
during the second year, etc. Work will generally occur from April
through October. Material offloading facilities will be constructed in
the first and second season, and a product loading facility will be
installed during seasons 2, 3, and 4. Installation of the gas pipeline
is planned for seasons 3 and 4 as well.
The number of sea otters takes by year was then estimated by
allocating the total expected take by proportion of each project
component occurring in each year. For example, the 2D seismic surveys
are planned for year 3, so all takes during 2D seismic surveys were
assigned to year 3. The resulting estimates of total Level B take by
year are shown in table 12.
Table 11--Noise-Generating Activities by Year. Activities Are Those With Source Levels Above 160 dB rms Within
Frequencies Heard by Sea Otters
Year Applicant Activity Area
2019: Season 1...................... Hilcorp/Harvest................ 3D seismic............... LCI
NCI geohazard surveys.... LCI
Pipeline maintenance MCI
(geohazard, water jet).
2020: Season 2...................... Hilcorp/Harvest................ 2D seismic............... LCI
Drilling activities LCI
driving, VSP) at 1 well.
Drilling activities MCI
driving, VSP) at 2 wells
Plug and abandon MCI
at 1 well in the NCI.
Pipeline maintenance MCI
(geohazard, water jet).
AGDC........................... Sheet pile driving at MCI
2021: Season 3...................... Hilcorp/Harvest................ Drilling activities LCI
driving, VSP) at 2 wells.
Sheet pile driving in LCI
AGDC........................... Pipeline maintenance MCI
(geohazard, water jet).
Sheet pile driving at MCI
Sheet pile driving at MCI
2022: Season 4...................... Hilcorp/Harvest................ Drilling activities LCI
(tugs, geohazard, pipe
driving, VSP) at 1 well.
AGDC........................... Pipeline maintenance MCI
(geohazard, water jet).
Impact pile driving at LCI
PLF: 80 48-inch piles,
63 60-inch piles.
Anchor handling for MCI
2023-2024: Season 5................. Hilcorp/Harvest................ Pipeline maintenance MCI
(geohazard, water jet).
AGDC........................... Impact pile driving at LCI
PLF: 40 48-inch piles,
80 60-inch piles.
Impact pile driving at LCI
PLF: 10 48-inch piles,
48 60-inch piles.
Anchor handling for MCI
LCI = Lower Cook Inlet, MCI = Middle Cook Inlet, NCI = North Cook Inlet, TB = Trading Bay, PLF = product loading
facility, TMOF = temporary material offloading facility, MMOF = mainline material offloading facility, VSP =
vertical seismic profiling.
Table 12--Estimates of Total Number of Takes by Level B Harassment by Year (or Project Season)
Year (Project season)
Take 2019 (Season 2020 (Season 2021 (Season 2022 (Season 2023 (Season
1) 2) 3) 4) 5)
Takes by year (season).......... 877 800 2 3 2
% takes by year (season)........ 52% 48% 0% 0% 0%
In order to conduct this analysis and estimate the potential amount
of take, several critical assumptions were made. Here we discuss these
assumptions, the potential sources of bias or error inherent in them,
and their effects on the analysis. Take by harassment is equated herein
with exposure to noise meeting or exceeding the specified criteria. We
assume all otters exposed to these noise levels will exhibit behavioral
responses that indicate harassment or disturbance. There are likely to
be a proportion of animals that respond in ways that indicate some
level of disturbance but do not experience significant biological
consequences. A correction factor was not applied. This may result in
overestimation in take calculations from exposure to underwater noise,
while our separate assumption that sea otters exposed to noise in the
air but not in the water do not independently experience harassment may
result in underestimation of take. The net effect is unknown.
Our estimates do not account for variable responses by age and sex.
Females with dependent pups and with pups that have recently weaned are
physiologically the most sensitive (Thometz et al. 2014) and most
likely to experience take from disturbance. There is not enough
information on composition of the Cook Inlet sea otter population in
the applicant's project area to incorporate individual variability
based on age and sex or to predict its influence on take estimates. We
therefore assume the response rates are uniform throughout the
population. The degree of over- or under-estimation of take is unknown.
The estimates of behavioral response presented here do not account
for the individual movements of animals away from the project area due
to avoidance or habituation. Our assessment of density does not change.
There is not enough information about the movement of sea otters in
response to specific disturbances to refine these assumptions. While
otters do have restricted movements and smaller home ranges than other
marine mammals and, therefore, are likely to be exposed to sound during
multiple days of work, it is unlikely that all otters will continue to
respond in the same manner. Otters may remain in the area, depart from
the area and return after activities are complete, or habituate to the
disturbance and no longer experience take. However, we have no data to
adjust for the likelihood of departure or habituation. In general, this
situation is likely to result in overestimation of the number of takes.
However, we also considered whether it would underestimate the impact
of take because the same animal may be taken multiple times. For most
animals, the effects of each repeated disturbance will be a short-term
change in behavior which will have no lasting effect on the animal's
survival or reproductive capacity. For a few animals, there may be more
severe consequences. The net effect of this assumption is
overestimation of take.
We do not account for an otter's time at the water's surface where
sound attenuates faster than in deeper water. The average dive time of
a northern sea otter is only 85 to 149 seconds (Bodkin et al. 2004;
Wolt et al. 2012). Wolt et al. (2012) found Prince William Sound sea
otters average 8.6 dives per feeding bout, and when multiplied by the
average dive time (149 sec), the average total time a sea otter spends
underwater during a feeding bout is about 21 minutes. Bodkin et al.
(2007) found the overall average activity budget (proportion of 24-hour
day) spent foraging and diving was 0.48 (11.4 hours per day), and 0.52
nondiving time (12.5 hours per day). Gelatt et al. (2002) found that
the percent time foraging ranged from 21 percent for females with very
young (less than 3 weeks of age) dependent pups to 52 percent for
females with old (greater than or equal to 10 weeks of age) pups.
Therefore, although exposure to underwater sound during a single dive
is limited, accumulation of exposure over time is expected. Our
assessment may cause some overestimation in this regard.
We also assume that the mitigation measures presented will be
effective for avoiding some level of take. However, additional
information is needed to quantify the effectiveness of mitigation. The
monitoring and reporting in this ITR will help fill this information
need in the future, but for this suite of planned activities, no
adjustments were made to estimate the number of takes that will be
avoided by applying effective mitigation measures. This scenario leads
to overestimation in calculation of take.
The current project description represents the applicant's best
expectation of how, where, and when work will proceed. We expect that
the current project description is an accurate depiction of the work
that will be conducted. Details provided in future applications for
LOAs under this regulation must provide accurate project details, which
may include minor changes from those described here. Minor changes to
the details of the specified activities, such as a change of the
specific vessels or a change in the start date of a specific activity,
are not expected to significantly change the overall estimates of take
or the conclusions reached in our analysis. In all cases, the most
about the project and the specific estimation parameters will be used,
along with methods that are consistent with those described here, to
calculate the effects of the activities and to ensure that the effects
remain concordant with the determinations of this rulemaking. Larger
project changes that result in significantly different effects on sea
otters would be outside of the scope of this ITR.
Potential Impacts on Sea Otter Stocks
The estimated number of takes by Level B harassment is 1,684
instances of take due to behavioral responses or TTS associated with
noise exposure. Among otters from the southwest Alaska stock, 417 Level
B takes are expected; and among the southcentral Alaska stock, 1,267
takes from Level B harassment are expected. The estimated number of
takes by Level A harassment is one from the southwest Alaska stock and
two instances of take from the southcentral Alaska stock due to PTS
associated with noise exposure. Combined, the expected number of Level
A and Level B takes is 418 takes from the southwest Alaska stock and
1,269 takes from the southcentral Alaska stock.
These levels represent a small proportion relative to the most
recent stock abundance estimates for sea otters. The estimated 418
takes is 0.9 percent of the best available estimate of the current
population size of 45,064 animals in the southwest Alaska stock (USFWS
2014a) (418 / 45,064 = 0.009). The estimate of 1,269 takes is about 6.9
percent of the 18,297 animals in the southcentral Alaska stock (USFWS
2014b) 1,269 / 18,297 = 0.069). For these analyses, we are emphasizing
the total number of takes rather than the number of animals taken. At
this time, there are insufficient data regarding the daily movement
patterns of individual sea otters in Cook Inlet to support an estimate
of the number of animals taken. Evaluation based on total take in this
situation is certain to be an overestimate of the actual impact, but it
avoids relying on an estimate of number of animals taken that is
precise, but possibly incorrect.
Sea otters exposed to sound produced by the project are likely to
respond with temporary behavioral modification or displacement. Project
activities could temporarily interrupt the feeding, resting, and
movement of sea otters. Because activities will occur during a limited
amount of time and in a localized region, the impacts associated with
the project are likewise temporary and localized. The anticipated
effects are primarily short-term behavioral reactions and displacement
of sea otters near active operations.
Animals that encounter the specified activities may exert more
energy than they would otherwise due to temporary cessation of feeding,
increased vigilance, and retreat from the project area. We expect that
affected sea otters would tolerate this exertion without measurable
effects on health or reproduction. Most of the anticipated takes would
be due to short-term Level B harassment in the form of TTS, startling
reactions, or temporary displacement. Three instances of Level A take
are expected to occur due to PTS. The effects of PTS in sea otters are
With the adoption of the measures proposed in the applicant's 4MP
and required by this ITR, the amount and likelihood of Level A and
Level B take will be reduced. The number of otters affected will be
small relative to the stocks, and the overall effect on the stocks is
expected to be negligible.
Potential Impacts on Subsistence Uses
The planned oil and gas activities will occur near marine
subsistence harvest areas used by Alaska Natives from the villages of
Ninilchik, Salamatof, Tyonek, Nanwalek, Seldovia, and Port Graham.
Between 2013 and 2018, approximately 491 sea otters were harvested for
subsistence use from Cook Inlet, averaging 98 per year. The large
majority were taken in Kachemak Bay. Harvest occurs year-round, but
peaks in April and May, with about 40 percent of the total taken at
that time. February and March are also high harvest periods, with about
10 percent of the total annual harvest occurring in each of those
months. The project area will avoid Kachemak Bay and therefore avoid
significant overlap with subsistence harvest areas. The applicant's
activities will not preclude access to hunting areas or interfere in
any way with individuals wishing to hunt. Vessels, aircraft, and
project noise may displace otters, resulting in changes to availability
of otters for subsistence use during the project period. Otters may be
more vigilant during periods of disturbance, which could affect hunting
success rates. The applicant will coordinate with Alaska Native
villages and Tribal organizations to identify and avoid potential
conflicts. If any conflicts are identified, the applicant will develop
a POC specifying the particular steps that will be taken to address any
effects the project might have on subsistence harvest. A POC will be
prepared for 3D surveys planned by Hilcorp and Harvest.
For small numbers analyses, the statute and legislative history do
not expressly require a specific type of numerical analysis, leaving
the determination of ``small'' to the agency's discretion. The
statutory definition is provided at 16 U.S.C. 1362; however, the
Service no longer relies upon or applies this regulatory definition.
The Court of Appeals for the Ninth Circuit (Center for Biological
Diversity v. Salazar, 695 F.3d 893, 902-907 [9th Cir. 2012]) has
determined that the regulatory definition conflates ``small numbers''
with ``negligible impact,'' whereas the MMPA establishes these as
Our small numbers analysis evaluates whether the number of marine
mammals anticipated to be taken is small relative or proportional to
the size of the overall population. A more precise formulation of
``small numbers'' is not possible because the concept is not capable of
being expressed in absolute numerical limits. The Court of Appeals for
the Ninth Circuit has expressly approved this type of analytical
approach (Center for Biological Diversity v. Salazar, 695 F.3d at 905-
To evaluate whether the specified oil and gas activities in Cook
Inlet would affect small numbers, we calculated the number of instances
of take that are predicted to result from the specified activities. We
then used the number of takes as a conservative estimate of the number
of animals taken to determine whether more than a small number would be
taken when compared with the size of the stock. We found that the
proposed project may result in approximately 1,687 takes, of which, 418
takes will be from the southwest Alaska stock and 1,269 takes will be
from the southcentral Alaska stock. Based on most recent stock
assessments (USFWS 2014a, b), the number of takes would equal about 1
percent of the southwest Alaska stock and 6.9 percent of the
southcentral Alaska stock.
Evaluation based on total take rather than numbers of animals
taken, is certain to be an overestimate of the actual impact because
some otters are likely to be taken multiple times during the work. We
determined it was appropriate to consider total take for these analyses
as the best available data regarding the daily movement patterns of sea
otters because there was not sufficient information to support an
accurate estimate of the number of individual animals affected by the
specific project activities. The available
information suggests that only a portion of the estimate of take will
be realized. Based on these numbers, we find that the applicant's
activities will take, by harassment, only a small number of animals
relative to the population sizes of the affected stocks.
We find that any incidental take by harassment resulting from the
proposed project cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the sea otter through effects on
annual rates of recruitment or survival and would, therefore, have no
more than a negligible impact on the species or stocks. In making this
finding, we considered the best available scientific information,
including: The biological and behavioral characteristics of the
species, the most recent information on species distribution and
abundance within the area of the specified activities, the potential
sources of disturbance caused by the project, and the potential
responses of animals to this disturbance. In addition, we reviewed
material supplied by the applicant, other operators in Alaska, our
files and datasets, published reference materials, and species experts.
Sea otters are likely to respond to specified activities with
temporary behavioral modification or displacement. These reactions are
unlikely to have consequences for the health, reproduction, or survival
of most affected animals. Most animals will respond to disturbance by
moving away from the source, which may cause temporary interruption of
foraging, resting, or other natural behaviors. Affected animals are
expected to resume normal behaviors soon after exposure, with no
lasting consequences. Some animals may exhibit more severe responses
typical of Level B harassment, such as fleeing, ceasing feeding, or
flushing from a haulout. These responses could have significant
biological impacts for affected individuals. Three otters may
experience Level A take from PTS. The effects to these individuals are
unknown, but lasting effects to survival and reproduction are possible.
Thus, although the specified activities may result in approximately 418
takes from the southwest Alaska stock and 1,269 takes from the
southcentral Alaska stock, we do not expect this level of harassment to
affect annual rates of recruitment or survival or result in adverse
effects on the species or stocks. The focus on total take, rather than
number of animals taken, for these analyses provides an overestimate of
the effects on stocks.
Our finding of negligible impact applies to incidental take
associated with the specified activities as mitigated by the avoidance
and minimization measures identified in the applicant's 4MP. Minimum
flight altitudes will help operators avoid take from exposure to
aircraft noise. Protected species observers and procedures implemented
by PSOs will limit Level A take during seismic work and pile driving.
Collision-avoidance measures, including speed reductions when otters
are present, will ensure that boat strikes are unlikely. These
mitigation measures are designed to minimize interactions with and
impacts to sea otters and, together with the monitoring and reporting
procedures, are required for the validity of our finding and are a
necessary component of the ITR. For these reasons, we find that the
specified activities will have a negligible impact on sea otters.
Impact on Subsistence
We find that the anticipated harassment caused by the applicant's
activities will not have an unmitigable adverse impact on the
availability of sea otters for taking for subsistence uses. In making
this finding, we considered the timing and location of the specified
activities and the timing and location of subsistence harvest
activities in the area of the proposed project. We considered the
comments received during the public comment period. We also considered
the applicant's consultation with subsistence communities, proposed
measures for avoiding impacts to subsistence harvest, and commitment to
development of a POC for project components that could have any adverse
impact on subsistence harvest. We based our finding on: (1) Initial
results of community outreach conducted by the applicant and the
Service; (2) the results of aerial surveys indicating the availability
of sea otters in Cook Inlet; (3) locations of hunting areas; and (4)
the limited potential for overlap of hunting areas and proposed
projects. The Service's confirms that through the coordination process
identified in the ITR, no take of sea otters will be authorized that
will result in an unmitigable adverse impact on the availability of sea
otters for subsistence harvest sufficient to meet the needs of coastal
dwelling Alaskan Natives.
Least Practicable Adverse Impacts
We find that the mitigation measures required by this ITR will
effect the least practicable adverse impacts from any incidental take
likely to occur in association with the specified activities. In making
this finding, we considered the biological characteristics of sea
otters, the nature of the specified activities, the potential effects
of the activities on sea otters, the documented impacts of similar
activities on sea otters, and alternative mitigation measures.
Monitoring and Reporting
The purposes of the monitoring requirements are: To document and
provide data for assessing the effects of specified activities on sea
otters; to ensure that take is consistent with that anticipated in the
small numbers, negligible impact, and subsistence use analyses; and to
detect any unanticipated effects on the species. Monitoring plans
include steps to document when and how sea otters are encountered, and
their numbers and behaviors during these encounters. This information
allows the Service to measure encounter rates and trends and to
estimate numbers of animals potentially affected. To the extent
possible, monitors will record group size, age, sex, reaction, duration
of interaction, and closest approach to the project activity.
Monitoring activities will be summarized and reported in a formal
report each year. The applicant must submit an annual monitoring and
reporting plan at least 90 days prior to the initiation of the
activity, and the applicant must submit a final monitoring report to us
no later than 90 days after the expiration of the LOA. We base each
year's monitoring objective on the previous year's monitoring results.
We require an approved plan for monitoring and reporting the effects of
oil and gas industry activities on sea otters prior to issuance of an
LOA. We require approval of the monitoring results for continued
operation under the LOA.
We find that this regulation will establish monitoring and
reporting requirements to evaluate the potential impacts of planned
activities and to ensure that the effects of the activities remain
consistent with the rest of the findings.
Summary of and Response to Comments and Recommendations
During the public comment period, we requested written comments
from the public on the proposed ITR as well as the draft EA. The
comment period on the proposed ITR opened on March 19, 2019 (84 FR
10224), and, in response to requests from the public, was extended on
April 5, 2019 (84 FR 13603). The comment period closed on April 19,
2019. We received 20 submissions; these included comments on the
proposed rule and the draft EA as well as a number of publications and
other documents submitted in support of those comments.
The Service received comments from the Marine Mammal Commission,
industry organizations, environmental organizations, local government
entities, Tribal organizations, and the public. We reviewed all
comments received for substantive issues, new information, and
recommendations regarding the proposed ITR and the draft EA. The
comments are aggregated by subject matter, summarized and addressed
below, and changes have been incorporated into the final rule as
appropriate. A summary of the changes to this final ITR from the
proposed ITR is found in the preamble section entitled, Summary of
Changes from the Proposed Rule.
Comment 1: Several commenters opposed the promulgation of the ITR
based on a general opposition to oil and gas industry activities.
Response 1: Language within section 101(a)(5)(A) of the MMPA
requires the Service to allow the incidental taking of small numbers of
marine mammals provided the Service has made certain determinations
regarding the specified activity. Once we make the required
determinations, we must promulgate the ITR. It is not our role in this
process to approve or deny the specified activities. Our mandate is to
identify and assess the potential impact of those activities on marine
mammals, and if our analysis concludes that such impacts are consistent
with the required determinations, we must promulgate an ITR.
Comment 2: Allowing any level of harassment is a threat to the
Response 2: We disagree. Based on our analysis we found that the
effects of the specified activities will have no more than a negligible
impact upon a small number of northern sea otters in Cook Inlet.
Comment 3: There is insufficient information on how sound affects
sea otters to determine the risks to the species; more research should
Response 3: While we acknowledge that additional research is needed
to refine the evaluation of the effects of sound exposure on sea
otters, we disagree with the comment that available information limits
the Service's ability to conduct the required analysis and make the
required determinations, which are based on the best scientific
information that is available.
Comment 4: The project actions will harm beluga whales.
Response 4: The effects to marine mammals other than sea otters are
outside of the scope of this rule and the authority of the Service. The
NMFS has jurisdiction over issuance of incidental take of beluga whales
and other cetacean and pinniped species in Cook Inlet.
Comment 5: Seismic surveys can harm fish and invertebrates, thereby
impeding prey availability and foraging for sea otters.
Response 5: The Service evaluated effects of the proposed seismic
surveys on sea otter prey availability to determine whether these
effects would lead to incidental take of otters. See Potential Effects
of the Activities, Effects on Habitat and Prey. As discussed in this
final rule, the expected effects of the planned seismic surveys on sea
otter prey will not result in lasting consequences for prey
availability or additional take of sea otters.
Comment 6: The description of activities considered for the ITR is
ambiguous. The Service should address these ambiguities and ensure that
the ITR is very specific about what the applicant can and cannot do to
make sure the LOA process is not open-ended.
Response 6: We disagree. Consistent with numerous previous ITRs,
this ITR provides an overall ``umbrella'' set of requirements which,
when followed, allow the incidental take of small numbers of sea otters
during certain oil and gas industry activities. The requirements ensure
that there is no more than a negligible impact on these species, the
activities will have the least practicable adverse impacts, and that
there will not be unmitigable impacts on the availability of these
species for subsistence use. The Service believes we have used the
appropriate level of detail necessary to evaluate the effects of the
specified activities within the 5-year period of the ITR consistent
with requirements of the MMPA.
Comment 7: Several commenters pointed out inconsistencies between
the project descriptions and the description of activities in the
Response 7: We verified the project descriptions with the applicant
and revised the project descriptions as needed in this final rule.
Comment 8: The public comment period should be extended; although
it was extended from 15 to 30 days, it was still too short.
Response 8: The Service determined that a 30-day comment period
would be sufficient for this rulemaking.
Comment 9: The Service should evaluate the harm and harassment of
the proposed action on units smaller than stocks.
Response 9: The Service believes that our evaluation of the
proposed activities at the stock level is consistent with section
101(a)(5) of the MMPA, which uses the term ``species or stock.'' We do
not believe an evaluation at a larger or smaller scale is appropriate.
Comment 10: Several commenters expressed concern that industry
activities and incidental take authorization could have an adverse
impact on Alaska Native subsistence use of sea otters. It was suggested
that the Service should ensure that all applicants submit, as part of
their LOA requests, a site-specific stakeholder engagement plan or POC
that includes a summary of input received, a schedule for ongoing
community engagement, and measures that would be implemented to
mitigate any potential conflicts with subsistence hunting.
Response 10: This ITR requires an LOA applicant to coordinate with
Alaska Native villages and Tribal organizations to identify and avoid
potential conflicts. If any conflicts are identified, the applicant
must develop a POC specifying the particular steps that will be taken
to address any effects the project might have on subsistence harvest.
Appropriate mitigation measures will be developed if conflicts are
identified. The applicant must conduct stakeholder engagement and make
this information available to the Service. Revisions have been made to
Sec. Sec. 18.134(b)(3) and 18.140(b) to incorporate these suggestions
and provide additional detail and clarity regarding the required
components of the stakeholder engagement plan and POC.
Comment 11: Neither the applicant nor the Service consulted with
federally recognized tribes or tribal organizations on this proposed
Response 11: We conducted outreach to all the tribal organizations
in the Cook Inlet region by email and postal letters. We received one
response requesting further consultation on this project from the
Native Village of Chickaloon. No other groups expressed interest. When
the Chickaloon Village Traditional Council (CVTC) and the Service were
not able to schedule a time and place suitable to both parties to
conduct the consultation, the CVTC chose to provide written comments to
the Service expressing their views on the ITR. See Comment 1 for our
Comment 12: The Service conflates small numbers and negligible
impact standards required by the MMPA.
Response 12: We disagree. As we explain in the preamble of this
ITR, we do not rely upon the definition of ``small numbers'' found in
50 CFR 18.27 as it conflates ``small numbers'' with ``negligible
impacts.'' We recognize ``small numbers'' and ``negligible impacts'' as
two separate and distinct requirements under the MMPA. The Service
maintains that the proposed oil and gas activities in Cook Inlet will
affect a small number of animals and will have a negligible effect on
the stocks, based on separate and discrete analyses for each of these
Comment 13: The conclusions in the proposed ITR that the activities
will have a negligible impact and take only small numbers are
Response 13: We disagree. The Service analysis of the specified
activities for this ITR used the best available information and
encapsulated all of the applicant's known and anticipated activities
that will occur in the Cook Inlet ITR Region during the 5-year period
of this ITR.
Comment 14: Cumulative impacts of multiple take authorizations in
Cook Inlet must be considered.
Response 14: In our negligible impacts assessment, we considered
the effects of a suite of human activities on sea otters in Cook Inlet,
including impacts from noise, vessel activities, human encounters, oil
spills, cumulative effects of existing and future development,
production, and exploration activities, and the likelihood of impacts
from these activities. We incorporated these impacts into the baseline
condition of the affected stocks to determine whether the issuance of
take would have more than a negligible effect.
Estimation of Take
Comment 15: The analysis does not adequately address effects of
noise on mothers with pups.
Response 15: While we acknowledge that mothers with pups are likely
to be among the most sensitive individuals to harassment, we believe
our analysis adequately addresses potential impacts to all life stages
as discussed in the preamble.
Comment 16: The estimates of numbers of takes and sea otters taken
do not correctly allocate the proportion of takes between the
southcentral and southwest Alaska stock resulting in underestimation of
take from the ESA-listed southwest Alaska stock. Methods used to
allocate take between stocks are insufficiently supported. The
assignment of the Level A take to the southcentral Alaska stock is
Response 16: We disagree. Take is calculated according to the
location, duration, and intensity of the specific component of the
work, and the density of sea otters exposed to work in that project
area. Estimates of the number of takes was based on the proportion of
each activity occurring within each stock boundary. For clarity, we
have added a table showing what proportion of each activity is expected
to occur within each stock boundary.
In response to this comment, we reevaluated whether the allocation
of Level A take was assigned to the appropriate stock. We determined
that the appropriate procedures were used to estimate Level A take
according to location and characteristics of the activity within each
stock boundary. However, we acknowledge that is it more appropriate in
this case to consider the total number of takes rather than the number
of animals taken. This change resulted in revision of the Level A take
estimate from three takes of one animal in the southcentral Alaska
stock, to two instances of take from the southwest Alaska stock and one
instance of take from the southcentral Alaska stock. Although we
determined in this final regulation that it was more appropriate to use
total takes rather than takes of animals, the proposed regulation,
which presented both methods for considering take, was not arbitrary.
Comment 17: Take is underestimated, and methods of take calculation
are not adequately disclosed.
Response 17: Take was calculated based on the best information
available at the time of the analysis and was done in a manner that any
necessary assumptions or estimates in input parameters would result in
overestimation of take rather than underestimation. We have added
additional text and an additional table to Estimated Incidental Take to
help describe how these take estimates were calculated.
Comment 18: The Service proposed that a very small number of sea
otters could be taken by Level B harassment relative to the estimated
number of sea otter takes. The number of individuals estimated to be
taken during the course of the regulations is unrealistic based on the
types of activities being conducted and the location and duration of
those activities. Mobile activities, such as seismic and geohazard
surveys, would be conducted over a large area and an extended period of
time, resulting in the exposure of more individuals than would be
exposed for stationary sources, such as pile driving.
Response 18: We employed a model for estimating the number of
animals taken based on the estimated number of takes. This model was
based on the available information at the time of the analysis. We
recognize that a more sophisticated model can be developed but, at this
time, there are insufficient data regarding the behaviors and movement
patterns of individual sea otters in Cook Inlet, and so we cannot be
confident that a more sophisticated model would accurately translate
the total number of takes into a more accurate estimate of the number
of animals taken. Therefore, rather than attempting to recalculate the
number of animals taken using a more sophisticated model that may be no
more accurate, we instead emphasize the importance of the total number
of takes in this final rule. We have evaluated whether the MMPA
determinations can be made based on the total number of takes rather
than solely on the number of animals taken in order to ensure that our
assessments do not underestimate the possible impacts to the stocks.
This approach has been used in previous analyses of incidental take of
marine mammals, both explicitly and implicitly, when a suitable
estimate of numbers of individuals could not be derived from available
information (e.g., 81 FR 52276, August 5, 2016; 81 FR 40902, June 23,
2016). Using total take to evaluate the effects of the specified
activities on sea otters in Cook Inlet is likely to be an overestimate
of the actual impact, but it avoids relying on an estimate of number of
animals taken that is precise, but possibly incorrect.
Comment 19: The proposed pile-driving activities will harm and
harass sea otters beyond the minimal estimates provided by the Service.
Response 19: We have determined that in the proposed ITR, we
underestimated the duration of pile-driving activities, but in
cooperation with the applicant, we have incorporated more accurate
estimates of the time needed to complete these activities to ensure the
effects are not underestimated. Further, the effects of specific pile
driving activities will be evaluated in individual LOAs to ensure
accurate project details are incorporated.
Comment 20: The Service incorrectly concludes that harassing the
same nine threatened sea otters 410 times will be inconsequential.
Response 20: The comment misinterprets our analysis in three ways.
As discussed in the response to Comment 18, the estimate of number of
animals taken was based on a model derived from the total number of
takes. However, for this suite of projects, the number of takes is a
more accurate assessment of the total impact of the activity, and our
assessment has been revised to reflect this. Secondly, for most
animals, the effects of disturbance will be short-term changes in
behavior, which will have no lasting effect on the animal's survival or
reproductive capacity. While there may be more severe consequences for
a few animals, our evaluation supports a determination that there will
be no significant consequences on the stocks to which these animals
belong, not that the effects to individual animals are inconsequential.
Finally, there is an implied omission of assessment of repeated
exposures. We addressed this issue in the text of the preamble in
Potential Effects of the Activities and Characterizing Take.
Comment 21: Airborne noise: The Service conflates exposures from
underwater sound sources with disturbing activities that do not
generate underwater sound. The proposed rule discounts the impacts of
noise in the air. The Service's conclusion that all take from aerial
surveys will be mitigated is arbitrary, and instead it must analyze the
potential for take from all sources of air traffic associated with the
Response 21: We disagree. We evaluated the full suite of project
activities to determine which are likely to cause sea otters to react
in ways that indicate take by Level A and Level B harassment. Take from
airborne noise was considered. We assessed the likelihood, frequency,
and severity of Level A and Level B take from airborne noise. Further
discussion of this issue can be found in the section on Airborne Sounds
in Effects of Noise.
Comment 22: The Service relies on avoidance to reduce sea otter
take; however, this is arbitrary and capricious because displacement
still amounts to harassment and even harm if it impedes a sea otter
from foraging or resting in its preferred habitat.
Response 22: The commenter has misinterpreted how take associated
with displacement is characterized and estimated in this rule.
Displacement indeed does constitute take if, as the commenter notes, it
impedes a sea otter from foraging or resting in preferred habitat and,
as we note, the resulting effort to forage or rest in suboptimal
habitat results in a biologically significant affect to the animal. Not
all displacement will cause take. Otters displaced to other areas of
suitable habitat and otters that are displaced, but do not experience a
biologically significant interruption in feeding or resting are not
considered taken. The analysis of take includes all animals exposed to
the specified activities that are expected to respond with behaviors
that indicate a Level A or Level B take has occurred, including
displacement leading to biologically significant interruption in
feeding and resting. We used the best available evidence based on the
biological characteristics and behaviors of sea otters, or a suitable
proxy, and the characteristics of the planned activities to identify
appropriate thresholds of exposure that are likely to result in take.
We have identified and used the same thresholds for northern and
southern sea otters in previous analyses (e.g., 83 FR 18077, April 25,
2018; 82 FR 6627, January 19, 2017, 83 FR 18330, April 26, 2018). Where
information was lacking, we used conservative assumptions to ensure
take, including that associated with displacement, was not
underestimated. In sum, take from displacement was incorporated in this
analysis, and the characterization of take associated with such
displacement was neither arbitrary nor capricious.
Comment 23: Seismic surveys will likely affect marine mammals in a
much larger area than anticipated by the application.
Response 23. We disagree. While the proposed survey may be
detectable to sea otters beyond the thresholds for take that we
identified here, to constitute take by harassment, the effects of
exposure must rise beyond detectability to cause a biologically
significant disruption of behavior. Many animals will have non-
significant responses, including short term increases in vigilance,
momentary startle responses, or short-term changes in body orientation
or direction of travel. To distinguish between non-significant
responses and those indicating take, the Service has used an exposure
threshold of 160 dB for underwater noise. See the comments regarding
use of a 120-dB threshold versus a 160 dB threshold (Comment 33) for
more discussion on the suitability of this threshold.
Comment 24: The upper end of the frequency of hearing for sea
otters should be 38 kHz rather than 32 kHz.
Response 24: We agree. This correction was made in the ITR.
Comment 25: Two commenters pointed out that the proposed ITR
evaluated vessel noise from tugs towing rigs but did not evaluate noise
from transiting vessels and suggested that, if general vessel use is
discounted as a source of potential harassment, use of the tug should
be as well.
Response 25: Tugs towing a rig are using high-powered engines and
are often working in teams, resulting in higher levels of underwater
noise than is typical of most vessel traffic. Tugs will be towing rigs
to areas in Cook Inlet where these activities are unusual. Otters in
these areas may show a greater level of vigilance or avoidance of these
activities than for most vessel traffic due to the novelty of the
activity in that area. We do not typically consider vessel traffic to
have the potential to result in take, but the applicant had initially
requested authorization of take that may occur during tug towing. The
Service evaluated the expected number of takes associated with tug
towing and found this activity would likely result in less than one
take. Accordingly, the applicant has since removed this request from
its application and the Service has removed tug towing from the
activities included in the final rule.
Comment 26: Anchor handling, pipe cutting, and grinding do not emit
sound levels sufficiently high to cause Level A or B harassment and
should not be included in the analyses.
Response 26: For activities with source levels nearing take
thresholds, the possibility of take was analyzed at the request of the
applicant and included in the overall take estimate in the proposed
rule. Results of our analyses indicated that take associated with these
activities is negligible. The applicants have since requested
withdrawal of grinding and pipe cutting from consideration but have
maintained inclusion of anchor handling. These changes are reflected in
Comment 27: Several commenters expressed that a 160-dB re 1 [mu]Pa
threshold is inadequate as it addresses only acoustic harassment and
does not account for takes resulting from behavioral changes,
particularly for continuous, non-impulsive sound sources.
The Marine Mammal Commission recommended that, until such time that
the 120- and 160-dB re 1 [mu]Pa thresholds are updated, the Service use
a 120- rather than 160-dB re 1 [mu]Pa threshold to estimate the extents
of the Level B harassment zones and numbers of sea otter takes when
non-impulsive, continuous sources are proposed for use. The Commission
further recommended that, if the Service did not use a 120-dB
threshold, then a 141-dB Level B harassment threshold should be used
for non-impulsive, continuous sources based on monitoring data from
the Elkhorn Slough National Estuarine Research Reserve (ESNERR) (2011).
Response 27: The highest spectral densities for noises generated by
vibratory pile driving lie within a range of frequencies at which sea
otters have poor hearing ability. In contrast, gray whales, on which
the 120-dB threshold is based, are highly sensitive to sounds within
this frequency range. We do not dispute that sea otters may hear and
may react to sounds produced by vibratory pile driving. However, we
maintain that it is unlikely that sea otters' reactions will be
equivalent to those of gray whales in terms of the sound levels that
elicit reactions equivalent to take by harassment. Thus, it is not
appropriate to apply the 120-dB threshold to sea otters.
The Service disagrees with the Commission's conclusions regarding
ESNERR (2011). After considering the Commission's comments and
reviewing the monitoring data (ESNERR 2011 and ESNERR unpublished data
2018), we reaffirm our statement that ``project-related monitoring of
sea otter behavior in areas exposed to underwater sound levels ranging
from approximately 135-165 dB during vibratory pile driving (ESNERR
2011) showed no clear pattern of disturbance or avoidance in relation
to these levels of underwater sound exposure.''
As such, we maintain that use of a 160-dB threshold for both
impulsive and non-impulsive sounds is consistent with the best
Comment 28: The tables summarizing source levels, repetition rates,
pulse durations, weighting factor adjustments, and other assumptions
for survey instruments were incorrect or inappropriate.
Response 28: Discrepancies or errors of the source levels and other
parameters for sound sources have been corrected in this rule.
Comment 29: The Commission recommended that chirps have temporal
and spectral characteristics suggesting that a lower, more
precautionary Level B harassment threshold of 120 dB would be more
appropriate than the 160-dB threshold. The Commission further
recommended that, until the behavior thresholds are updated, the
Service requires applicants to use the 120- rather than 160-dB
threshold for intermittent, non-impulsive sources (such as chirps).
Response 29: The Service considers sub-bottom profilers, including
chirps, to be impulsive sources. Continuous sounds are characterized by
having a sound pressure level that consistently stays above ambient
levels and negligible fluctuations (NIOSH 1998; ANSI 2005).
Intermittent sounds, with cyclical periods of lower or no sound level,
can further be classified as either impulsive or non-impulsive.
Impulsive sounds are brief (less than 1 second) and transient, with
rapid rise time to a high peak pressure followed by a rapid decay (ANSI
1986; NIOSH 1998). Non-impulsive sounds have more gradual rise times
and gradual decays. Sounds from sub-bottom profilers more closely
resemble impulsive sounds, as opposed to non-impulsive or continuous
sounds, and the Service treats them as such.
Regardless of how sounds emitted by chirps are classified, the
references cited by the Commission in support of use of a 120dB
threshold are overwhelmingly based on cetaceans in the high-frequency
and mid-frequency functional hearing groups (harbor porpoise, killer
whale, beaked whale, sperm whale, Lagenorhynchus and Stenella
dolphins). These animals have significantly greater sensitivity to and
utilization of high frequency sounds, therefore the results of those
studies are not applicable to sea otters.
Comment 30: The Commission strongly suggested that the Service
consult with NMFS regarding the appropriateness of the various
thresholds. The Commissions also recommended that the Service take a
more active role in the development, review, and implementation of any
and all acoustic and behavior thresholds for marine mammal species
under its jurisdiction and consult with NMFS on whether, when, and how
NMFS' current thresholds should be implemented.
Response 30: The Service responded to the Commission's previous
letters and advice consistent with our repeated response here. The
Service continues to evaluate impacts resulting from anthropogenic
sound on marine mammals under our jurisdiction using the best available
information. We are aware of and supportive of the efforts by NMFS and
its Science Centers to develop their Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing Acoustic
Guidelines for those species under NMFS' jurisdiction. Although the
Service provided informal comments on an early version of these
guidelines, we did not provide additional comments because the guidance
is specific to management of species under the jurisdiction of the
Department of Commerce. The Service will continue to work with our
partners, including the U.S. Geological Survey and NMFS, to obtain the
best scientific information concerning potential effects of
anthropogenic sound on marine mammal species under our jurisdiction.
Mitigation and Monitoring Comments
Comment 31: Several commenters indicated the need for additional
Protected Species Observers to monitor Level A and B harassment zones.
Response 31: The issuance of an LOA for the specific activities
under this ITR is contingent upon an applicant developing and
implementing a detailed monitoring plan to ensure that the effects of
the activities on marine mammals are documented and reported. If the
monitoring plan is incomplete, inadequate, or not implemented, the LOA
will not be issued, or if issued, may be rescinded.
Effective monitoring is a necessary component of this rule. An
applicant for an LOA must submit, as part of the application, a
detailed marine mammal monitoring and mitigation plan. It must include
a sufficient number of PSOs to conduct visual project monitoring of 100
percent of a project's EZs during all daytime periods of underwater
noise-generating work. Sea otters in the SZ must be documented and
reported. These monitoring methods, included in this rule, were
evaluated and found to be sufficient for detecting responses to project
activities. We considered alternative monitoring methods and added a
discussion of mitigation measures considered but not required in the
section on the Mitigation and Monitoring.
Comment 32: The Service should clarify that ramp up procedures for
vibratory pile driving differ from those for impact pile driving.
Response 32: Clarifying text has been added to Sec.
Comment 33: Mitigation requiring shut downs to be accomplished
within several seconds does not adequately consider worker health and
safety, and equipment safety and integrity. The Service should consider
modifying this language from ``within several seconds'' to ``as soon as
is practicable considering worker safety and equipment integrity''.
Response 33: The suggested text has been added to Sec.
Comment 34: Mitigation measures apply to ``in-water work along the
shoreline'' however, this term is not defined. The Service should
replace the phrase ``in-water work along the shoreline'' with ``work
occurring in intertidal areas.''
Response 34: The suggested clarifying change was made to Sec.
Comment 35: Hilcorp and Harvest's 4MP states that they plan to
perform a sound source verification (SSV) for the 3D seismic survey in
LCI and will work with the Service to determine if an SSV is needed for
other activities occurring
in the project area. However, the Service did not include a requirement
in the proposed rule for any applicant to conduct an SSV for any
seismic or other activities. The Commission recommended that the
Service require the applicant to conduct SSVs at the beginning of
noise-generating activities for any sound sources for which in-situ
measurements have not been made for similar activities in Cook Inlet
and use those measurements to verify and adjust, if necessary, the
extents of the Level A and B harassment zones.
Response 35: The omission of the SSV requirement for the 3D seismic
survey in Cook Inlet is noted and has been corrected in this rule. We
will work with the applicant to determine whether additional SSVs for
other planned activities are appropriate and necessary.
Comment 36: The Service has proposed to use power-down procedures
during seismic survey activities as an alternative to implementing a
full shutdown when an animal is detected within or approaching the
Level A harassment zone, which would necessitate a ramp-up of the full
array. Power-downs also may be used at the operator's discretion to
reduce the likelihood of a Level B harassment take. In a mitigation and
monitoring workshop for seismic surveys, industry representatives
indicated that power-downs may ultimately increase sound input to the
marine environment due to the need to subsequently re-shoot the
trackline to prevent gaps in data acquisition (unpublished workshop
report cited in 82 FR 26255, June 6, 2017). For that reason and because
a power down may not actually be useful, NMFS has prohibited the use of
power-downs in its issuance of incidental harassment authorizations for
taking of marine mammals associated with geophysical surveys in the
Atlantic Ocean (83 FR 63350, December 7, 2018), which the Commission
supported. The Commission therefore recommends that the Service
prohibit using power-down procedures as a mitigation measure for
seismic surveys in Cook Inlet.
Response 36: The Service agrees that, generally, it is best to
minimize survey gaps and re-shoots. We disagree with the Commission's
assertion that a voluntary power-down to avoid Level B take is not
In the instance of avoiding Level A take, mitigation is not
voluntary. Either a power-down or a shutdown would interrupt survey
activity to a degree that will create a survey gap requiring re-shoot.
Regardless of which of the two options is applied, a duration of longer
than 10 minutes would require a ramp-up to restore the array to full
Survey gaps are undesirable to operators as they result in a loss
of data continuity and there are significant costs associated with
reshoots. The Service thinks it unlikely that an operator would choose
to employ voluntary shutdowns either frequently or frivolously. In an
encounter with an unusually large group of animals, a voluntary power-
down may prevent exposure of a larger number of animals than would be
exposed during infill shooting at a later time with typical encounter
rates or group sizes. While we would encourage observers and operators
to use voluntary power-downs as infrequently as is practicable, we feel
that prohibition of this mitigation measure may ultimately result in an
increase in exposure of marine mammals to noise.
Comment 37: The Service also would allow the use of a 10-in\3\
mitigation gun to avoid requiring operators to ramp up after the full
array has not been in use (e.g., during a line turn, low-visibility
conditions, or other short-term interruption of seismic survey
activities). In its issuance of incidental harassment authorizations
for taking of marine mammals associated with geophysical surveys in the
Atlantic Ocean, NMFS required that the acoustic source be deactivated
when not acquiring or preparing to acquire data, except as necessary
for testing, and that unnecessary use of the acoustic source be avoided
(83 FR 63351, December 7, 2018). The Commission supports that
requirement for the reasons previously stated and recommends that the
Service prohibit the use of a mitigation gun to avoid implementing
Response 37: The Commission has mischaracterized the Service's
proposed use of a mitigation gun; specifically, the proposed ITR did
not suggest that ramp-up procedures may be avoided by use of a
mitigation gun. Rather, we proposed use of a mitigation gun to reduce
the probability of the presence of undetected animals within the SZ
prior to initiation of ramp-up procedures during periods of poor
While it is true that IHAs recently issued by NMFS for seismic
surveys in the Atlantic prohibited airgun use during line turns and
other short-term interruptions of survey activities, the use of Passive
Acoustic Monitoring (PAM) was authorized as an avenue to clear the SZ
of marine mammals and initiate ramp-up procedures during times when the
SZ would not be visible (e.g., at nighttime or during periods of rain
or fog). The Service does not believe PAM to be an effective monitoring
and mitigation tool for Hilcorp and Harvest's proposed survey because
(1) the high levels of ambient noise in Cook Inlet interfere with
detections of underwater vocalizations; and (2) sea otters are not
known to make underwater vocalizations. The Service contends that,
within Cook Inlet, the use of a mitigation gun during line-change turns
remains among the best practices to reduce the probability of animals
being present within the SZ immediately prior to and during ramp-up
Comment 38: The Service has proposed that operators notify the
Service or the Alaska Sea Life Center within 48 hours of an injured,
dead, or distressed sea otter being observed, irrespective of whether
an injury or death was associated with the specified activities
(Sec. Sec. 18.136(b) and 18.139(f) of the proposed rule). Any injury
or death of a sea otter associated with the specified activities should
be reported immediately to the Service or the Alaska Sea Life Center.
And, in the past, the Service has specified that notification of
injured or dead otters not associated with project activities occur
within 24 hours to allow for a more timely response by trained
personnel as warranted. As such, the Commission recommends that the
Service require the operators to notify the Service or the Alaska Sea
Life Center as follows: (1) Immediately if a sea otter is injured or
killed during any of the project activities; and (2) within 24 hours of
observing an injured, dead, or distressed sea otter that the observer
determined is not associated with project activities.
Response 38: The applicant has committed to notifying the Alaska
Sea Life Center and the Service as recommended.
Comment 39: The Service should employ time or area restrictions to
mitigate acoustic impacts rather than relying on lookouts aboard
vessels because many disruptions to marine mammal behavior will be
difficult to detect or avoid through lookouts.
Response 39: We disagree. There is no information currently
available about daily or seasonal movement patterns of otters in Cook
Inlet on which to base effective timing restrictions. Ship-based PSOs
are limited in their ability to monitor sea otter behaviors, but this
remains the most effective way to ensure the project activities will
have the least practicable adverse impact on sea otters in Cook Inlet.
Comment 40: The Service cannot, as it has here, rely on a plan to
make a plan to mitigate the impacts of the specified activities on sea
otters. It also may not
rubberstamp the mitigation measures proposed by the applicant, but it
must consider the practicality of other measures.
Response 40: The mitigation measures that have been developed for
the project are developed based on the industry standards for seismic
surveys, geotechnical work, pile driving, and other oil and gas work.
The mitigation measures presented in the section on Mitigation and
Monitoring and in this rule under Sec. 18.137 Mitigation include the
mitigation measures required by regulation and the full suite of marine
mammal monitoring and mitigation measures for activities proposed by
Hilcorp and Harvest, and are incorporated here by reference
(Fairweather Science LLC 2018). The AGDC will be expected to implement
similar measures and meet similar standards for monitoring. Although
site-specific 4MP will be required for an applicant to obtain an LOA
under this rule, the expectations for the content of these plans are
well established and constitute substantially more than ``a plan to
make a plan.''
Additionally we have added language to the section on Mitigation
and Monitoring, and have summarized our assessment under Findings,
Least Practicable Adverse Impacts. That language describes alternative
mitigation measures that were considered and demonstrates why we
determined that the selected mitigation will achieve the least
practicable adverse impact of the proposed actions on sea otters. We
have worked with Hilcorp, Harvest, and AGDC to incorporate these
measures into their project plans as much as possible to ensure that
these measures are practicable and will be implemented as intended. The
mitigation measures required by this rule are therefore reflected in
the application documents.
Comment 41: The Service should consider requiring alternative
technologies to seismic surveys.
Response 41: We considered whether alternative technologies should
be required. We added language to the section on Mitigation and
Monitoring describing our evaluation.
Comment 42: The Service should require lowest practicable source
levels for seismic surveys and in-situ sound source verification for
Response 42: Hilcorp and Harvest have determined that the minimum
source level necessary to provide the target data will be between 1,760
in\3\ and 2,400 in\3\. The anticipated seismic source is a 14-airgun
array with a total volume of 1,945 in\3\. We evaluated the possible
effects on sea otters of the use of a 2,400 ci\3\ array. We have
included a requirement to use equipment that generates the lowest
practicable source levels during seismic surveys. Onsite SSV testing
will be conducted prior to 2D and (3D) seismic surveys. Mitigation
measures (D) and (E) have been added to paragraph (b)(1)(ii) of Sec.
Comment 43: The Service should prescribe compensatory mitigation,
such as habitat restoration, for the adverse impacts of the permitted
activity on marine mammals and their habitat that cannot be prevented
or mitigated by modifying the activity.
Response 43: Compensatory mitigation is not required under the
MMPA. Mitigation measures must be specified that achieve the least
practicable adverse impact of the action on sea otters in Cook Inlet.
No effective or practicable compensatory mitigation efforts have been
identified for sea otters in this area. We added this information to
the discussion of mitigation measures considered but not required under
the section on Mitigation and Monitoring.
Comment 44: Because sea otters may be sensitive to seismic surveys
at the 160 dB threshold, or Level B take; the EZ should be extended and
Response 44: The EZ is the area where work that generates noise
above Level A thresholds in the frequency range audible to sea otters
must shut down or power down when sea otters are present. The EZ is
comprehensively monitored. Work may not begin when 100 percent of the
EZ is not visible or until after a 30-minute observation period has
confirmed no otters are present in the EZ. Shutting down or powering
down sound sources in response to the presence of sea otters in the
160-dB zone (the SZ) would reduce take. However, the applicant has
determined that shutting down or powering down sound sources in
response to any sea otter in the 160-dB SZ would not be practicable for
conducting the planned activities.
Comment 45: Projects should be shut down during periods of limited
Response 45: The applicant has indicated that it is not practicable
to shut down during periods of low visibility and still complete the
work. We recognize that this will limit the effectiveness of visual
monitoring by PSOs and have accounted for this in our estimation of
Comment 46: Bubble curtains or other noise-reduction technologies
should be explored for use in the proposed project, as well as non-
pile-driven foundation types (e.g., gravity-based, or suction
Response 46: The Service has determined that sound-attenuation
devices and alternatives to pile-supported construction may be
effective means for achieving the least practicable adverse impact of
the specified activities. We have added evaluation of these tools on a
project-by-project basis to the required mitigation measures of this
rule. Each LOA will specify whether these tools will be required and
what type will be used.
Comment 47: Vessel speed should be limited to 10 knots or less.
Response 47: Lowering vessel speed can reduce the risk of serious
injury and mortality of marine mammals caused by ship strikes and can
reduce ocean noise that can mask marine mammal communications.
Requirements for vessels to reduce speed in the vicinity of sea otters
or when visibility is limited are included in Sec. 18.137, paragraphs
(d)(3) and (d)(5).
National Environmental Policy Act (NEPA)
Comment 48: The draft EA is inadequate, and the Service must
prepare a full environmental impact statement, and the draft EA fails
to meet the requirements of NEPA.
Response 48: Section 1501.4(b) of NEPA, found at 40 CFR Chapter V,
notes that, in determining whether to prepare an environmental impact
statement (EIS), a Federal agency may prepare an EA and, based on the
EA document, make a determination whether to prepare an EIS. The
Department of the Interior's policy and procedures for compliance with
NEPA (69 FR 10866, March 8, 2004) further affirms that the purpose of
an EA is to allow the responsible official to determine whether to
prepare an EIS or a FONSI. The Service analyzed the proposed activity,
i.e., issuance of implementing regulations, in accordance with the
criteria of NEPA, and made a determination that it does not constitute
a major Federal action significantly affecting the quality of the human
environment. It should be noted that the Service does not authorize the
actual oil and gas industry activities, as those activities are
authorized by other State and Federal agencies. The Service merely
authorizes the incidental take of sea otters resulting from those
activities. We note that this ITR provides the Service with a means of
interacting with the applicant through the mitigation, monitoring, and
reporting requirements for individual projects to ensure that the
impacts to sea otters are minimized. The ITR will authorize the
incidental take of only small numbers of sea otters, will have only a
negligible impact on the species or stocks, and will not cause an
unmitigable adverse impact on the availability of the species for
subsistence use. As a result, we determined the regulations will not
significantly affect the quality of the human environment and,
therefore, a FONSI is appropriate. Accordingly, an EIS is not required
Comment 49: The EA is overly narrow in scope, fails to evaluate
alternatives, and does not adequately evaluate the potential impacts of
the action on the physical and biological environment.
Response 49: The Service believes the commenters misunderstand the
requirements set forth in NEPA and the MMPA. The proposed action set
forth in the EA is not activities proposed by Hilcorp, Harvest, and
AGDC, but the issuance of incidental take authorization of sea otters.
The Service believes we are in full compliance with both NEPA and the
MMPA. We refer to our response to Comment 48 for an explanation of NEPA
requirements and we refer to the Background section of the preamble of
this rule for an explanation of MMPA requirements.
In addition to the proposed action, we analyzed the ``no action''
alternative. The Service believes the no action alternative is valid
and is in compliance with relevant court rulings (see, for example,
Center for Biological Diversity v. Kempthorne, 588 F.3d 701, 9th Cir.
2009). The action being considered is the issuance of the ITR.
Therefore, the ``no action'' alternative would be not to issue an ITR.
However, Section 101(a)(5)(A) of the MMPA specifies that the Secretary
of the Interior (Secretary), through the Director of the Service, shall
[emphasis added] allow the incidental, but not intentional, taking of
small numbers of marine mammals in response to requests by U.S.
citizens engaged in a specified activity (other than commercial
fishing) in a specified geographic region if the Secretary finds that
the total of such taking will have a negligible impact on the species
or stock and will not have an unmitigable adverse impact on the
availability of the species or stock for subsistence uses. Therefore,
if a citizen petitions the Service to promulgate regulations, we are
required to initiate the process and make the appropriate findings. If
there is no request for an ITR, there would be no need for any
analysis, including alternatives.
Comment 50: The Service's cumulative impacts analysis is deficient.
The indirect and cumulative impacts of greenhouse gas pollution from
operations and downstream consumption of fossil fuels must be analyzed,
and effects of ocean warming and acidification must be considered.
Response 50: The Service has considered the effects of climate
change in our assessment of cumulative impacts. We considered the best
available information regarding potential impacts of climate change and
analyzed all relevant direct, indirect, and cumulative effects on sea
otters, and their habitat, potentially caused by the specified
activities in the Cook Inlet region during the 5-year period of this
ITR. The level of analysis the commenters suggest is beyond the scope
appropriate for this ITR. We do consider broader questions about
climate change and how it may cause additive stress on sea otter
populations over the long term generally in the EA. The Service finds
that, while greenhouse gas emissions are clearly contributing to
climate change, the comprehensive authority to regulate those emissions
is not found in the statutes that govern the management of marine
mammals. The challenge posed by climate change and its ultimate
solution is much broader than the scope and scale of this ITR and EA.
Comment 51: The Service must comply with the Endangered Species
Response 51: As required by section 7 of the ESA the Service has
completed an intra-Service consultation under the ESA for the listed
stock of sea otters and their critical habitat prior to promulgating
Oil Spill Risks and Effects
Comment 52: The project activities present an unacceptable risk of
oil spills especially considering Hilcorp's aging infrastructure and
poor record of safety and environmental compliance.
Response 52: We acknowledge that an oil spill is a possible outcome
of the specified activities in Cook Inlet, and for this reason we have
discussed potential spills and their impacts to sea otters (see
Potential Impacts from an Oil Spill or Unpermitted Discharge). It is
beyond the authority of the Service and the MMPA to regulate potential
accidental discharge into the environment. Waste product discharge into
the environment is regulated under other laws and permits, such as
provisions of the Clean Water Act (33 U.S.C. 1251 et seq.) and the Oil
Pollution Act (33 U.S.C. 2701 et seq.), among others. However, we have
considered the likelihood of spills resulting from the activities in
Cook Inlet, and have determined that there is a low probability of a
major spill. Small spills are more likely, but we have determined that,
should they occur, they will likely affect only a small number of sea
otters, will have a negligible impact on these stocks, and will not
have an unmitigable adverse impact on their availability for
National Environmental Policy Act (NEPA)
We have prepared an EA in accordance with the NEPA of 1969 (42
U.S.C. 4321 et seq.) and have concluded that issuance of an ITR for the
nonlethal, incidental, unintentional take by harassment of small
numbers of sea otters in Alaska during activities conducted by Hilcorp,
Harvest, and AGDC in 2019 to 2024 is not a major Federal action
significantly affecting the quality of the human environment within the
meaning of section 102(2)(C) of the NEPA. A copy of the EA and the
Service's FONSI can be obtained from the locations described in
Endangered Species Act (ESA)
Under the ESA, all Federal agencies are required to ensure the
actions they authorize are not likely to jeopardize the continued
existence of any threatened or endangered species or result in
destruction or adverse modification of critical habitat. The southwest
DPS of sea otters is listed as threatened under the ESA at 50 CFR
17.11(h) (70 FR 46366, August 9, 2005). The planned activities will
occur within designated critical habitat found at 50 CFR 17.95(a).
Prior to issuance of this final ITR, we completed an intra-Service
consultation under section 7 of the ESA on our proposed issuance of an
ITR. The evaluations and findings that resulted from this consultation
are available on the Service's website and at https://www.regulations.gov.
Regulatory Planning and Review
Executive Order 12866 provides that the Office of Information and
Regulatory Affairs (OIRA) in the Office of Management and Budget (OMB)
will review all significant rules for a determination of significance.
OMB has designated this rule as not significant.
Executive Order 13563 reaffirms the principles of Executive Order
12866 while calling for improvements in the nation's regulatory system
to promote predictability, to reduce uncertainty, and to use the best,
most innovative, and least burdensome tools for achieving regulatory
ends. The executive order directs agencies to consider regulatory
approaches that reduce burdens and maintain flexibility
and freedom of choice for the public where these approaches are
relevant, feasible, and consistent with regulatory objectives.
Executive Order 13563 emphasizes further that regulations must be based
on the best available science and that the rulemaking process must
allow for public participation and an open exchange of ideas. We have
developed this rule in a manner consistent with these requirements.
OIRA bases its determination of significance upon the following
four criteria: (a) Whether the rule will have an annual effect of $100
million or more on the economy or adversely affect an economic sector,
productivity, jobs, the environment, or other units of the government;
(b) Whether the rule will create inconsistencies with other Federal
agencies' actions; (c) Whether the rule will materially affect
entitlements, grants, user fees, loan programs, or the rights and
obligations of their recipients; (d) Whether the rule raises novel
legal or policy issues.
Expenses will be related to, but not necessarily limited to: The
development of applications for LOAs; monitoring, recordkeeping, and
reporting activities conducted during oil and gas operations;
development of activity- and species-specific marine mammal monitoring
and mitigation plans; and coordination with Alaska Natives to minimize
effects of operations on subsistence hunting. Realistically, costs of
compliance with this rule are minimal in comparison to those related to
actual oil and gas exploration, development, production, and transport
operations. The actual costs to develop the petition for promulgation
of regulations and LOA requests probably do not exceed $200,000 per
year, short of the ``major rule'' threshold that would require
preparation of a regulatory impact analysis. As is presently the case,
profits will accrue to the applicant; royalties and taxes will accrue
to the Government; and the rule will have little or no impact on
decisions by the applicant to relinquish tracts and write off bonus
Small Business Regulatory Enforcement Fairness Act
We have determined that this rule is not a major rule under 5
U.S.C. 804(2), the Small Business Regulatory Enforcement Fairness Act.
The rule is also not likely to result in a major increase in costs or
prices for consumers, individual industries, or government agencies or
have significant adverse effects on competition, employment,
productivity, innovation, or on the ability of United States-based
enterprises to compete with foreign-based enterprises in domestic or
Regulatory Flexibility Act
We have determined that this rule will not have a significant
economic effect on a substantial number of small entities under the
Regulatory Flexibility Act (5 U.S.C. 601 et seq.). Hilcorp, Harvest,
AGDC, and their contractors conducting exploration, development,
production, and transportation of oil and gas in Cook Inlet, Alaska,
are the only entities subject to this ITR. Therefore, neither a
Regulatory Flexibility Analysis nor a Small Entity Compliance Guide is
This rule does not have takings implications under Executive Order
12630 because it authorizes the nonlethal, incidental, but not
intentional, take of sea otters by oil and gas industry companies and,
thereby, exempts these companies from civil and criminal liability as
long as they operate in compliance with the terms of their LOAs.
Therefore, a takings implications assessment is not required.
This rule does not contain policies with Federalism implications
sufficient to warrant preparation of a Federalism Assessment under
Executive Order 13132. The MMPA gives the Service the authority and
responsibility to protect sea otters.
Unfunded Mandates Reform Act
In accordance with the Unfunded Mandates Reform Act (2 U.S.C. 1501
et seq.), this rule will not ``significantly or uniquely'' affect small
governments. A Small Government Agency Plan is not required. The
Service has determined and certifies pursuant to the Unfunded Mandates
Reform Act that this rulemaking will not impose a cost of $100 million
or more in any given year on local or State governments or private
entities. This rule will not produce a Federal mandate of $100 million
or greater in any year, i.e., it is not a ``significant regulatory
action'' under the Unfunded Mandates Reform Act.
Government-to-Government Relationship With Native American Tribal
It is our responsibility to communicate and work directly on a
Government-to-Government basis with federally recognized Alaska Native
tribes and corporations in developing programs for healthy ecosystems.
We seek their full and meaningful participation in evaluating and
addressing conservation concerns for protected species. It is our goal
to remain sensitive to Alaska Native culture, and to make information
available to Alaska Natives. Our efforts are guided by the following
policies and directives: (1) The Native American Policy of the Service
(January 20, 2016); (2) the Alaska Native Relations Policy (currently
in draft form); (3) Executive Order 13175 (January 9, 2000); (4)
Department of the Interior Secretarial Orders 3206 (June 5, 1997), 3225
(January 19, 2001), 3317 (December 1, 2011), and 3342 (October 21,
2016); (5) the Alaska Government-to-Government Policy (a departmental
memorandum issued January 18, 2001); and (6) the Department of the
Interior's policies on consultation with Alaska Native tribes and
We have evaluated possible effects of the specified activities on
federally recognized Alaska Native Tribes and corporations. Through the
ITR process identified in the MMPA, the applicant has presented a
communication process, culminating in a POC if needed, with the Native
organizations and communities most likely to be affected by their work.
The applicant has engaged these groups in informational communications.
We invited continued discussion about the proposed ITR.
We received a request for Government-to-Government consultation on
this ITR from the Chickaloon Village Traditional Council (CVTC). When
the CVTC and the Service were not able to schedule a time and place
suitable to both parties to conduct the consultation, the CVTC chose to
provide written comments to the Service expressing their views on the
ITR. We have responded to their comments under Summary of and Response
to Comments and Recommendations and will continue to engage with CVTC
to determine whether further consultation is desired.
Civil Justice Reform
The Departmental Solicitor's Office has determined that this
regulation does not unduly burden the judicial system and meets the
applicable standards provided in sections 3(a) and 3(b)(2) of Executive
Paperwork Reduction Act
This rule includes a revision to an existing information
collection. All information collections require approval under the
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). We may not
conduct or sponsor, and you are not required to respond to, a
collection of information unless it displays a currently valid OMB
The OMB previously reviewed and approved the information collection
requirements associated with incidental take of marine mammals in the
Beaufort and Chukchi Seas and assigned OMB Control Number 1018-0070
(expires July 31, 2020).
The revised requirements reporting and/or recordkeeping
requirements identified below were approved by OMB:
(1) Remove references to 50 CFR 18 subpart I (expired); and
(2) Add references to 50 CFR 18 subpart K.
Title of Collection: Incidental Take of Marine Mammals During
Specified Activities, 50 CFR 18.27 and 50 CFR 18, Subparts J and K.
OMB Control Number: 1018-0070.
Form Numbers: None.
Type of Review: Revision of a currently approved collection.
Respondents/Affected Public: Oil and gas industry representatives,
including applicants for ITRs and LOAs, operations managers, and
environmental compliance personnel.
Total Estimated Number of Annual Respondents: 84.
Total Estimated Number of Annual Responses: 356.
Estimated Completion Time per Response: Varies from 1.5 hours to
150 hours, depending on activity.
Total Estimated Number of Annual Burden Hours: 1,800.
Respondent's Obligation: Required to obtain or retain a benefit.
Frequency of Collection: On occasion.
Total Estimated Annual Non-hour Burden Cost: $200,000.
You may send comments on any aspect of this information collection
to the Service Information Collection Clearance Officer, U.S. Fish and
Wildlife Service, 5275 Leesburg Pike, MS: JAO/1N, Falls Church, VA
22041-3803 (mail); or Info_Coll@fws.gov (email). Please reference OMB
Control Number 1018-BD63/0070 in the subject line of your comments
Executive Order 13211 requires agencies to prepare Statements of
Energy Effects when undertaking certain actions. This rule provides
exceptions from the taking prohibitions of the MMPA for entities
engaged in the exploration of oil and gas in Cook Inlet, Alaska. By
providing certainty regarding compliance with the MMPA, this rule will
have a positive effect on the oil and gas industry and its activities.
Although the rule requires an applicant to take a number of actions,
these actions have been undertaken as part of oil and gas industry
operations for many years as part of similar past regulations in
Alaska. Therefore, this rule is not expected to significantly affect
energy supplies, distribution, or use and does not constitute a
significant energy action. No Statement of Energy Effects is required.
For a list of the references cited in this rule, see Docket No.
FWS-R7-ES-2019-0012, available at https://www.regulations.gov.
List of Subjects in 50 CFR Part 18
Administrative practice and procedure, Alaska, Imports, Indians,
Marine mammals, Oil and gas exploration, Reporting and recordkeeping
For the reasons set forth in the preamble, the Service amends part
18, subchapter B of chapter 1, title 50 of the Code of Federal
Regulations as set forth below.
PART 18--MARINE MAMMALS
1. The authority citation of 50 CFR part 18 continues to read as
Authority: 16 U.S.C. 1361 et seq.
2. Add subpart K to read as follows:
Subpart K--Nonlethal Taking of Marine Mammals Incidental to Oil and Gas
Activities in Cook Inlet, Alaska
18.130 Specified activities covered by this subpart.
18.131 Specified geographic region where this subpart applies.
18.132 Dates this subpart is in effect.
18.133 Authorized take allowed under a Letter of Authorization
18.134 Procedure to obtain a Letter of Authorization (LOA).
18.135 How the Service will evaluate a request for a Letter of
18.136 Prohibited take under a Letter of Authorization (LOA).
18.139 Reporting requirements.
18.140 Measures to reduce impacts to subsistence users.
18.141 Information collection requirements.
Subpart K--Nonlethal Taking of Marine Mammals Incidental to Oil and
Gas Activities in Cook Inlet, Alaska
Sec. 18.130 Specified activities covered by this subpart.
Regulations in this subpart apply to the nonlethal incidental, but
not intentional, take, as defined in 50 CFR 18.3 and under the Marine
Mammal Protection Act (16 U.S.C. 1362), of small numbers of northern
sea otters (Enhydra lutris kenyoni; hereafter ``otter,'' ``otters,'' or
``sea otters'') by Hilcorp Alaska, LLC, Harvest Alaska, LLC, and the
Alaska Gasline Development Corporation while engaged in activities
associated with or in support of oil and gas exploration, development,
production, and transportation in Cook Inlet, Alaska.
Sec. 18.131 Specified geographic region where this subpart applies.
(a) The specified geographic region is Cook Inlet, Alaska, south of
a line from the Susitna River Delta to Point Possession (approximately
61[deg]15'54'' N, 150[deg]41'07'' W, to 61[deg]02'19'' N,
150[deg]23'48'' W, WGS 1984) and north of a line from Rocky Cove to
Coal Cove (approximately 59[deg]25'56'' N, 153[deg]44'25'' W and
59[deg]23'48'' N, 151[deg]54'28'' W, WGS 1984), excluding Ursus Cove,
Iniskin Bay, Iliamna Bay, and Tuxedni Bay.
(b) The geographic area of this incidental take regulation (ITR)
includes all Alaska State waters and Outer Continental Shelf Federal
waters within this area as well as all adjacent rivers, estuaries, and
coastal lands where sea otters may occur, except for those areas
explicitly excluded in paragraph (a) of this section.
(c) Map of the Cook Inlet ITR region follows:
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Sec. 18.132 Dates this subpart is in effect.
Regulations in this subpart are effective from August 1, 2019, to
August 1, 2024.
Sec. 18.133 Authorized take allowed under a Letter of Authorization
(a) To incidentally take marine mammals pursuant to the regulations
in this subpart,, Hilcorp Alaska, LLC, Harvest Alaska, LLC, or the
Alaska Gasline Development Corporation (hereafter ``the applicant'')
must apply for and obtain an LOA in accordance with Sec. Sec. 18.27(f)
and 18.134. The applicant is a U.S. citizen as defined in Sec.
(b) An LOA allows for the nonlethal, incidental, but not
intentional take by harassment of sea otters during activities
specified in Sec. 18.130 within the Cook Inlet ITR region described in
(c) Each LOA will set forth:
(1) Permissible methods of incidental take;
(2) Means of effecting the least practicable adverse impact (i.e.,
mitigation) on the species, its habitat, and the availability of the
species for subsistence uses; and
(3) Requirements for monitoring and reporting.
(d) Issuance of the LOA(s) must be based on a determination that
the level of take will be consistent with the findings made for the
total allowable take under these regulations in this subpart.
Sec. 18.134 Procedure to obtain a Letter of Authorization (LOA).
(a) The applicant must submit the request for authorization to the
U.S. Fish and Wildlife Service (Service) Alaska Region Marine Mammals
Management Office (MMM), MS 341, 1011 East Tudor Road, Anchorage,
Alaska, 99503, at least 90 days prior to the start of the proposed
(b) The request for an LOA must comply with the requirements set
forth in Sec. Sec. 18.137 through 18.139 and must include the
(1) A plan of operations that describes in detail the proposed
activity (type of project, methods, and types and numbers of equipment
and personnel, etc.), the dates and duration of the activity, and the
specific locations of and areas affected by the activity. Changes to
the proposed project without prior authorization may invalidate an LOA.
(2) A site-specific marine mammal monitoring and mitigation plan to
monitor and mitigate the effects of the activity on sea otters.
(3) An assessment of potential effects of the proposed activity on
subsistence hunting of sea otters.
(i) The applicant must communicate with potentially affected
subsistence communities along the Cook Inlet coast and appropriate
subsistence user organizations to discuss the location, timing, and
methods of proposed activities and identify any potential conflicts
with subsistence hunting activities.
(ii) The applicant must specifically inquire of relevant
communities and organizations if the proposed activity will interfere
with the availability of sea otters for the subsistence use of those
(iii) The applicant must include documentation of consultations
with potentially affected user groups.
Documentation must include a list of persons contacted, a summary of
input received, any concerns identified by community members and hunter
organizations, and the applicant's responses to identified concerns.
(iv) If any concerns regarding effects of the activity on sea otter
subsistence harvest are identified, the applicant will provide to the
Service a Plan of Cooperation (POC) with specific steps for addressing
those concerns, including a schedule for ongoing community engagement
and suggested measures that will be implemented to mitigate any
potential conflicts with subsistence hunting.
Sec. 18.135 How the Service will evaluate a request for a Letter of
(a) The Service will evaluate each request for an LOA to determine
if the proposed activity is consistent with the analysis and findings
made for these regulations. Depending on the results of the evaluation,
we may grant the authorization, add further conditions, or deny the
(b) Once issued, the Service may withdraw or suspend an LOA if the
project activity is modified in a way that undermines the results of
the previous evaluation, if the conditions of the regulations in this
subpart are not being substantially complied with, or if the taking
allowed is or may be having more than a negligible impact on the
affected stock of sea otters or an unmitigable adverse impact on the
availability of sea otters for subsistence uses.
(c) The Service will make decisions concerning withdrawals of an
LOA, either on an individual or class basis, only after notice and
opportunity for public comment in accordance with Sec. 18.27(f)(5).
The requirement for notice and public comment will not apply should we
determine that an emergency exists that poses a significant risk to the
well-being of the species or stocks of sea otters.
Sec. 18.136 Prohibited take under a Letter of Authorization (LOA).
(a) Except as otherwise provided in this subpart, prohibited taking
is described in Sec. 18.11 as well as: Intentional take, lethal
incidental take of sea otters, and any take that fails to comply with
this subpart or with the terms and conditions of an LOA.
(b) If project activities cause unauthorized take, the applicant
must take the following actions:
(1) Cease activities immediately (or reduce activities to the
minimum level necessary to maintain safety) and report the details of
the incident to the Service MMM within 48 hours; and
(2) Suspend further activities until the Service has reviewed the
circumstances, determined whether additional mitigation measures are
necessary to avoid further unauthorized taking, and notified the
applicant that it may resume project activities.
Sec. 18.137 Mitigation.
(a) Mitigation measures for all LOAs. The applicant, including all
personnel operating under the applicant's authority (or ``operators,''
including contractors, subcontractors, and representatives) must
undertake the following activities to avoid and minimize take of sea
otters by harassment.
(1) Implement policies and procedures to avoid interactions with
and minimize to the greatest extent practicable adverse impacts on sea
otters, their habitat, and the availability of these marine mammals for
(2) Develop avoidance and minimization policies and procedures, in
cooperation with the Service, that include temporal or spatial activity
restrictions to be used in response to the presence of sea otters
engaged in a biologically significant activity (e.g., resting, feeding,
hauling out, mating, or nursing).
(3) Cooperate with the Service's MMM Office and other designated
Federal, State, and local agencies to monitor and mitigate the impacts
of oil and gas industry activities on sea otters.
(4) Allow Service personnel or the Service's designated
representative to board project vessels or visit project work sites for
the purpose of monitoring impacts to sea otters and subsistence uses of
sea otters at any time throughout project activities so long as it is
safe to do so.
(5) Designate trained and qualified protected species observers
(PSOs) to monitor for the presence of sea otters, initiate mitigation
measures, and monitor, record, and report the effects of the activities
on sea otters. The applicant is responsible for providing training to
PSOs to carry out mitigation and monitoring.
(6) Have an approved mitigation and monitoring plan on file with
the Service MMM and onsite that includes the following information:
(i) The type of activity and where and when the activity will occur
(i.e., a summary of the plan of operation);
(ii) Personnel training policies, procedures, and materials;
(iii) Site-specific sea otter interaction risk evaluation and
(iv) Sea otter avoidance and encounter procedures; and
(v) Sea otter observation and reporting procedures.
(7) Contact affected subsistence communities and hunter
organizations to identify any potential conflicts that may be caused by
the proposed activities and provide the Service documentation of
communications as described in Sec. 18.134.
(b) Mitigation measures for in-water noise-generating work. The
applicant must carry out the following measures:
(1) Mitigation zones. Establish mitigation zones for project
activities that generate underwater sound levels >=160 decibels (dB)
between 125 hertz (Hz) and 38 kilohertz (kHz) (hereafter ``noise-
(i) All dB levels are referenced to 1 [micro]Pa for underwater
sound. All dB levels herein are dBRMS unless otherwise
noted; dBRMS refers to the root-mean-squared dB level, the
square root of the average of the squared sound pressure level,
typically measured over 1 second.
(ii) Mitigation zones must include all in-water areas where work-
related sound received by sea otters will match the levels and
frequencies in paragraph (b)(1) of this section. Mitigation zones will
be designated as follows:
(A) An Exclusion Zone (EZ) will be established throughout all areas
where sea otters may be exposed to sound levels capable of causing
Level A take as shown in the table in paragraph (b)(1)(iii) of this
(B) The Safety Zone (SZ) is an area larger than the EZ and will
include all areas within which sea otters may be exposed to noise
levels that will likely result in Level B take as shown in the table in
paragraph (b)(1)(iii) of this section.
(C) Both the EZ and SZ will be centered on the sound source. The
method of estimation and minimum radius of each zone will be specified
in any LOA issued under Sec. 18.135 and will be based on onsite sound
source verification (SSV), if available, or the best available science.
(D) Onsite SSV testing will be conducted prior to two-dimensional
(2D) and three-dimensional (3D) seismic surveys.
(E) Seismic surveys (2D and 3D) must be conducted using equipment
that generates the lowest practicable levels of underwater sound within
the range of frequencies audible to sea otters.
(iii) Summary of acoustic exposure thresholds for take of sea
otters from underwater sound in the frequency range 125 Hz-38 kHz:
Table 1 to Sec. 18.137(b)(1)(iii)
Injury (Level A) threshold \1\ Disturbance (Level B) threshold
Marine mammals -------------------------------------------------------------------------------
Impulsive Non-impulsive All
Sea otters...................... 232 dB peak; 203 dB 219 dB SELCUM...... 160 dBRMS.
\1\ Based on acoustic criteria for otariid pinnipeds from the National Marine Fisheries Service. Sound source
types are separated into impulsive (e.g., seismic, pipe driving, sub-bottom profiler) and non-impulsive
(drilling, water jet) and require estimation of the distance to the peak received sound pressure level (peak)
and 24-hr cumulative sound exposure level (SELCUM).
(2) Monitoring. Designate trained and qualified PSOs or
``observers'' to monitor for the presence of sea otters in mitigation
zones, initiate mitigation measures, and record and report the effects
of project work on otters for all noise-generating work.
(3) Mitigation measures for sea otters in mitigation zones. The
following actions will be taken in response to otters in mitigation
(i) Sea otters that are under no visible distress within the SZ
must be monitored continuously. Power down, shut down, or maneuver away
from the sea otter if practicable to reduce sound received by the
animal. Maintain 100-m (301-ft) separation distance whenever possible.
Exposures in this zone are counted as one Level B take per animal per
(ii) When sea otters are observed within or approaching the EZ,
noise-generating work as defined in paragraph (b)(1) of this section
must be immediately shut down or powered down to reduce the size of the
zone sufficiently to exclude the animal from the zone. Vessel speed or
course may be altered to achieve the same task. Exposures in this zone
are counted as one Level A take per animal per day.
(iii) When sea otters are observed in visible distress (for
example, vocalizing, repeatedly spy-hopping, or fleeing), noise-
generating work as defined in paragraph (b)(1) of this section must be
immediately shut down or powered down to reduce the size of the zone
sufficiently to exclude the animal from the zone.
(iv) Following a shutdown, the noise-generating activity will not
resume until the sea otter has cleared the EZ. The animal will be
considered to have cleared the EZ if it is visually observed to have
left the EZ or has not been seen within the EZ for 30 minutes or
(4) Ramp-up procedures. Prior to noise-generating work, a ``ramp-
up'' procedure must be used to increase the levels of underwater sound
from noise-generating work at a gradual rate.
(i) Seismic surveys: A ramp-up will be used at the initial start of
airgun operations and prior to restarting after any period greater than
10 minutes without airgun operations, including a power-down or
shutdown event (described in paragraphs (b)(6) and (7) of this
section). During geophysical work, the number and total volume of
airguns will be increased incrementally until the full volume is
achieved. The rate of ramp-up will be no more than 6 dB per 5-minute
period. Ramp-up will begin with the smallest gun in the array that is
being used for all airgun array configurations. During the ramp-up, the
applicable mitigation zones (based on type of airgun and sound levels
produced) must be maintained. It will not be permissible to ramp up the
full array from a complete shutdown in thick fog or at other times when
the outer part of the EZ is not visible. Ramp-up of the airguns will
not be initiated if a sea otter is sighted within the EZ at any time.
(ii) Pile/pipe driving: A ramp-up of the hammering will precede
each day's pipe/pile driving activities or if pipe/pile driving has
ceased for more than 1 hour. The EZ will be determined clear of sea
otters 30 minutes prior to a ramp-up to ensure no sea otters are within
or entering the EZ. Initial hammering starts will not begin during
periods of poor visibility (e.g., night, fog, wind) when the entire EZ
is not visible. The ramp-up procedure for impact hammers involves
initially starting with three soft strikes at 40 percent energy,
followed by a 1-minute waiting period followed by two subsequent three-
strike sets. For vibratory hammers, initial noise generation will be
limited to 15 seconds at a reduced energy level, followed by a 1-minute
waiting period. This cycle will be repeated two additional times.
Monitoring will occur during all hammering sessions.
(iii) All activities: Any shutdown due to sea otters sighted within
the EZ must be followed by a 30-minute all-clear period and then a
standard full ramp-up. Any shutdown for other reasons resulting in the
cessation of the sound source for a period greater than 30 minutes must
also be followed by full ramp-up procedures. If otters are observed
during a ramp-up effort or prior to startup, a PSO must record the
observation and monitor the animal's position until it moves out of
visual range. Noise-generating work may commence if, after a full and
gradual effort to ramp up the underwater sound level, the otter is
outside of the EZ and does not show signs of visible distress (for
example, vocalizing, repeatedly spy-hopping, or fleeing).
(5) Startup procedures. (i) Visual monitoring must begin at least
30 minutes prior to, and continue throughout, ramp-up efforts.
(ii) Visual monitoring must continue during all noise-generating
work occurring in daylight hours.
(6) Power-down procedures. A power-down procedure involves reducing
the volume of underwater sound generated to prevent an otter from
entering the EZ.
(i) Whenever a sea otter is detected outside the EZ and, based on
its position and motion relative to the noise-generating work, appears
likely to enter the EZ but has not yet done so, operators may reduce
power to noise-generating equipment as an alternative to a shutdown.
(ii) Whenever a sea otter is detected in the SZ, an operator may
power down when practicable to reduce Level B take.
(iii) During a power-down of seismic work, the number of airguns in
use may be reduced, such that the EZ is reduced, making the sea otters
unlikely to enter the EZ. A mitigation airgun (airgun of small volume
such as the 10-in\3\ gun) will be operated continuously during a power-
down of seismic work.
(iv) After a power-down, noise-generating work will not resume
until the sea otter has cleared the applicable EZ. The animal will be
considered to have cleared the applicable zone if it is visually
observed to have left the EZ and has not been seen within the zone for
(7) Shutdown procedure. A shutdown occurs when all noise-generating
work is suspended.
(i) Noise-generating work will be shut down completely if a sea
otter enters the EZ.
(ii) The shutdown procedure will be accomplished within several
seconds of the determination that a sea otter is either in or about to
enter the EZ or as
soon as practicable considering worker safety and equipment integrity.
(iii) Noise-generating work will not proceed until all sea otters
have cleared the EZ and the PSOs on duty are confident that no sea
otters remain within the EZ. An otter will be considered to have
cleared the EZ if it is visually observed to have left the EZ or has
not been seen within the zone for 30 minutes.
(iv) Visual monitoring must continue for 30 minutes after use of
the acoustic source ceases or the sun sets, whichever is later.
(8) Emergency shutdown. If observations are made or credible
reports are received that one or more sea otters are within the area of
noise-generating work and are indicating acute distress associated with
the work, such as any injury due to seismic noise or persistent
vocalizations indicating separation of mother from pup, the work will
be immediately shut down and the Service contacted. Work will not be
restarted until review and approval by the Service.
(9) To ensure the proposed activities remain consistent with the
estimated take of sea otters, operators may not conduct 3D seismic
surveys where doing so will generate underwater noise levels that are
likely to exceed acoustic exposure thresholds within areas of estimated
sea otter densities greater than 0.026 otters per km. Maps of the areas
will be provided to 3D seismic operators and may be adjusted based on
SSV results. This does not apply to 2D seismic surveys.
(c) Mitigation for all in-water construction and demolition
activity. (1) The applicant must implement a minimum EZ of a 10-m
radius around the in-water construction and demolition. If a sea otter
comes within or approaches the EZ, such operations must cease. A larger
EZ may be required for some activities, such as blasting, and will be
specified in the LOA.
(2) All work in intertidal areas shall be conducted during low tide
when the site is dewatered to the maximum extent practicable.
(3) The applicant must evaluate alternatives to pile-supported
facilities. If no practicable alternative exists, the applicant must
then evaluate the use of sound-attenuation devices such as pile caps
and cushions, bubble curtains, and dewatered cofferdams during
construction. The Service may require sound-attenuation devices or
alternatives to pile-supported designs.
(d) Measures for vessel-based activities. (1) Vessel operators must
take every precaution to avoid harassment of sea otters when a vessel
is operating near these animals.
(2) Vessels must remain at least 500 m from rafts of otters unless
safety is a factor.
(3) Vessels must reduce speed and maintain a distance of 100 m (328
ft) from all sea otters unless safety is a factor.
(4) Vessels must not be operated in such a way as to separate
members of a group of sea otters from other members of the group.
(5) When weather conditions require, such as when visibility drops,
vessels must adjust speed accordingly to avoid the likelihood of injury
to sea otters.
(6) Vessels in transit and support vessels must use established
navigation channels or commonly recognized vessel traffic corridors,
and must avoid alongshore travel in shallow water (<20 m) whenever
(7) All vessels must avoid areas of active or anticipated
subsistence hunting for sea otters as determined through community
(8) Vessel operators must be provided written guidance for avoiding
collisions and minimizing disturbances to sea otters. Guidance will
include measures identified in paragraphs (d)(1) through (7) of this
(e) Mitigation measures for aircraft activities. (1) Aircraft must
maintain a minimum altitude of 305 m (1,000 ft) to avoid unnecessary
harassment of sea otters, except during takeoff and landing, and when a
lower flight altitude is necessary for safety due to weather or
(2) Aircraft must not be operated in such a way as to separate
members of a group of sea otters from other members of the group.
(3) All aircraft must avoid areas of active or anticipated
subsistence hunting for sea otters as determined through community
(4) Unmanned aerial systems or drones must not cause take by
harassment of sea otters. Measures for avoidance of take may be
required in an LOA, and may include maintaining a minimum altitude and
horizontal distance no less than 100 m away from otters, conducting
continuous visual monitoring by PSOs, and ceasing activities in
response to sea otter behaviors indicating any reaction to drones.
Sec. 18.138 Monitoring.
(a) Operators shall work with PSOs to apply mitigation measures,
and shall recognize the authority of PSOs, up to and including stopping
work, except where doing so poses a significant safety risk to
(b) Duties of PSOs include watching for and identifying sea otters,
recording observation details, documenting presence in any applicable
monitoring zone, identifying and documenting potential harassment, and
working with operators to implement all appropriate mitigation
(c) A sufficient number of PSOs will be available to meet the
following criteria: 100 percent monitoring of EZs during all daytime
periods of underwater noise-generating work; a maximum of 4 consecutive
hours on watch per PSO; a maximum of approximately 12 hours on watch
per day per PSO.
(d) All PSOs will complete a training course designed to
familiarize individuals with monitoring and data collection procedures.
A field crew leader with prior experience as a sea otter observer will
supervise the PSO team. Initially, new or inexperienced PSOs will be
paired with experienced PSOs so that the quality of marine mammal
observations and data recording is kept consistent. Resumes for
candidate PSOs will be made available for the Service to review.
(e) Observers will be provided with reticule binoculars (10x42),
big-eye binoculars or spotting scopes (30x), inclinometers, and range
finders. Field guides, instructional handbooks, maps and a contact list
will also be made available.
(f) Observers will collect data using the following procedures:
(1) All data will be recorded onto a field form or database.
(2) Global positioning system data, sea state, wind force, and
weather will be collected at the beginning and end of a monitoring
period, every hour in between, at the change of an observer, and upon
sightings of sea otters.
(3) Observation records of sea otters will include date; time; the
observer's locations, heading, and speed (if moving); weather;
visibility; number of animals; group size and composition (adults/
juveniles); and the location of the animals (or distance and direction
from the observer).
(4) Observation records will also include initial behaviors of the
sea otters, descriptions of project activities and underwater sound
levels being generated, the position of sea otters relative to
applicable monitoring and mitigation zones, any mitigation measures
applied, and any apparent reactions to the project activities before
and after mitigation.
(5) For all otters in or near a mitigation zone, observers will
record the distance from the vessel to the sea otter upon initial
duration of the encounter, and the distance at last observation in
order to monitor cumulative sound exposures.
(6) Observers will note any instances of animals lingering close to
or traveling with vessels for prolonged periods of time.
Sec. 18.139 Reporting requirements.
(a) Operators must notify the Service at least 48 hours prior to
commencement of activities.
(b) Weekly reports will be submitted to the Service during in-water
seismic activities. The reports will summarize project activities,
monitoring efforts conducted by PSOs, the number of sea otters
detected, the number exposed to sound levels greater than 160 dB, SSV
results, and descriptions of all behavioral reactions of sea otters to
(c) Monthly reports will be submitted to the Service MMM for all
months during which noise-generating work takes place. The monthly
report will contain and summarize the following information: Dates,
times, weather, and sea conditions (including Cook Inlet marine state
and wind force) when sea otters were sighted; the number, location,
distance from the sound source, and behavior of the otters; the
associated project activities; and a description of the implementation
and effectiveness of mitigation measures with a discussion of any
specific behaviors the otters exhibited in response to mitigation.
(d) A final report will be submitted to the Service within 90 days
after the expiration of each LOA. It will include the following items:
(1) Summary of monitoring efforts (hours of monitoring, activities
monitored, number of PSOs, and, if requested by the Service, the daily
(2) All project activities will be described, along with any
additional work yet to be done. Factors influencing visibility and
detectability of marine mammals (e.g., sea state, number of observers,
and fog and glare) will be discussed.
(3) The report will also address factors affecting the presence and
distribution of sea otters (e.g., weather, sea state, and project
activities). An estimate will be included of the number of sea otters
exposed to noise at received levels greater than or equal to 160 dB
(based on visual observation).
(4) The report will describe changes in sea otter behavior
resulting from project activities and any specific behaviors of
(5) It will provide a discussion of the mitigation measures
implemented during project activities and their observed effectiveness
for minimizing impacts to sea otters. Sea otter observation records
will be provided to the Service in the form of electronic database or
(6) The report will also evaluate the effectiveness of the POC (if
applicable) for preventing impacts to subsistence users of sea otters,
and it will assess any effects the operations may have had on the
availability of sea otters for subsistence harvest.
(e) All reports shall be submitted by email to
(f) Injured, dead, or distressed sea otters that are not associated
with project activities (e.g., animals known to be from outside the
project area, previously wounded animals, or carcasses with moderate to
advanced decomposition or scavenger damage) must be reported to the
Service within 24 hours of the discovery to either the Service MMM (1-
800-362-5148, business hours); or the Alaska SeaLife Center in Seward
(1-888-774-7325, 24 hours a day); or both. Photographs, video, location
information, or any other available documentation shall be provided to
(g) Operators must notify the Service upon project completion or
end of the work season.
Sec. 18.140 Measures to reduce impacts to subsistence users.
(a) Prior to conducting the work, the applicant will take the
following steps to reduce potential effects on subsistence harvest of
(1) Avoid work in areas of known sea otter subsistence harvest;
(2) Discuss the planned activities with subsistence stakeholders
including Cook Inlet villages, traditional councils, and the Cook Inlet
Regional Citizens Advisory Council;
(3) Identify and work to resolve concerns of stakeholders regarding
the project's effects on subsistence hunting of sea otters; and
(b) If any unresolved or ongoing concerns remain, develop a POC in
consultation with the Service and subsistence stakeholders to address
these concerns. The POC must include a schedule for ongoing community
engagement and specific measures for mitigating any potential conflicts
with subsistence hunting.
Sec. 18.141 Information collection requirements.
(a) We may not conduct or sponsor, and a person is not required to
respond to, a collection of information unless it displays a currently
valid Office of Management and Budget (OMB) control number. OMB has
approved the collection of information contained in this subpart and
assigned OMB control number 1018-0070. The applicant must respond to
this information collection request to obtain a benefit pursuant to
section 101(a)(5) of the Marine Mammal Protection Act. We will use the
(1) Evaluate the application and determine whether or not to issue
specific LOAs; and
(2) Monitor impacts of activities and effectiveness of mitigation
measures conducted under the LOAs.
(b) Comments regarding the burden estimate or any other aspect of
this requirement must be submitted to the Information Collection
Clearance Officer, U.S. Fish and Wildlife Service, at the address
listed in 50 CFR part 2.1.
Dated: July 18, 2019.
Deputy Solicitor for Parks and Wildlife, Exercising the Authority of
the Assistant Secretary for Fish and Wildlife and Parks.
[FR Doc. 2019-16279 Filed 7-26-19; 4:15 pm]
BILLING CODE 4333-15-P