Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Oil and Gas Activities in Cook Inlet, Alaska, 12330-12377 [2019-05781]
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Federal Register / Vol. 84, No. 62 / Monday, April 1, 2019 / Proposed Rules
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
50 CFR Part 217
[Docket No. 190214112–9112–01]
RIN 0648–BI62
Takes of Marine Mammals Incidental to
Specified Activities; Taking Marine
Mammals Incidental to Oil and Gas
Activities in Cook Inlet, Alaska
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Proposed rule; request for
comments.
AGENCY:
NMFS has received a request
from Hilcorp Alaska LLC (Hilcorp) for
authorization to take marine mammals
incidental to oil and gas activities in
Cook Inlet, Alaska, over the course of
five years (2019–2024). As required by
the Marine Mammal Protection Act
(MMPA), NMFS is proposing
regulations to govern that take, and
requests comments on the proposed
regulations. NMFS will consider public
comments prior to making any final
decision on the issuance of the
requested MMPA authorization, and
agency responses will be summarized in
the final notice of our decision.
DATES: Comments and information must
be received no later than May 1, 2019.
ADDRESSES: You may submit comments,
identified by NOAA–NMFS–2019–0026,
by any of the following methods:
• Electronic submissions: Submit all
electronic public comments via the
Federal eRulemaking Portal, Go to
www.regulations.gov/
#!docketDetail;D=NOAA-NMFS-20190026, click the ‘‘Comment Now!’’ icon,
complete the required fields, and enter
or attach your comments.
• Mail: Submit comments to Jolie
Harrison, Chief, Permits and
Conservation Division, Office of
Protected Resources, National Marine
Fisheries Service, 1315 East-West
Highway, Silver Spring, MD 20910–
3225.
Instructions: Comments sent by any
other method, to any other address or
individual, or received after the end of
the comment period, may not be
considered by NMFS. All comments
received are a part of the public record
and will generally be posted for public
viewing on www.regulations.gov
without change. All personal identifying
information (e.g., name, address, etc.),
confidential business information, or
SUMMARY:
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otherwise sensitive information
submitted voluntarily by the sender may
be publicly accessible. Do not submit
Confidential Business Information or
otherwise sensitive or protected
information. NMFS will accept
anonymous comments (enter ‘‘N/A’’ in
the required fields if you wish to remain
anonymous). Attachments to electronic
comments will be accepted in Microsoft
Word, Excel, or Adobe PDF file formats
only.
FOR FURTHER INFORMATION CONTACT: Sara
Young, Office of Protected Resources,
NMFS, (301) 427–8401. Electronic
copies of the application and supporting
documents, as well as a list of the
references cited in this document, may
be obtained online at: https://
www.fisheries.noaa.gov/national/
marine-mammal-protection/incidentaltake-authorizations-oil-and-gas. In case
of problems accessing these documents,
please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Purpose and Need for Regulatory
Action
This proposed rule would establish a
framework under the authority of the
MMPA (16 U.S.C. 1361 et seq.) to allow
for the authorization of take of marine
mammals incidental to Hilcorp’s oil and
gas activities in Cook Inlet, Alaska.
We received an application from
Hilcorp requesting five-year regulations
and authorization to take multiple
species of marine mammals. Take
would occur by Level A and Level B
harassment incidental to a variety of
sources including: 2D and 3D seismic
surveys, geohazard surveys, vibratory
sheet pile driving, and drilling of
exploratory wells. Please see
‘‘Background’’ below for definitions of
harassment.
Legal Authority for the Proposed Action
Section 101(a)(5)(A) of the MMPA (16
U.S.C. 1371(a)(5)(A)) directs the
Secretary of Commerce to allow, upon
request, the incidental, but not
intentional taking of small numbers of
marine mammals by U.S. citizens who
engage in a specified activity (other than
commercial fishing) within a specified
geographical region for up to five years
if, after notice and public comment, the
agency makes certain findings and
issues regulations that set forth
permissible methods of taking pursuant
to that activity and other means of
effecting the least practicable adverse
impact on the affected species or stocks
and their habitat (see the discussion
below in the ‘‘Proposed Mitigation’’
section), as well as monitoring and
reporting requirements. Section
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101(a)(5)(A) of the MMPA and the
implementing regulations at 50 CFR part
216, subpart I provide the legal basis for
issuing this proposed rule containing
five-year regulations, and for any
subsequent letters of authorization
(LOAs). As directed by this legal
authority, this proposed rule contains
mitigation, monitoring, and reporting
requirements.
Summary of Major Provisions Within
the Proposed Rule
Following is a summary of the major
provisions of this proposed rule
regarding Hilcorp’s activities. These
measures include:
• Required monitoring of the
ensonified areas to detect the presence
of marine mammals before beginning
activities;
• Shutdown of activities under
certain circumstances to minimize
injury of marine mammals;
• Ramp up at the beginning of
seismic surveying to allow marine
mammals the opportunity to leave the
area prior to beginning the survey at full
power, as well as power downs, and
vessel strike avoidance;
• Ramp up of impact hammering of
the drive pipe for the conductor pipe
driven from the drill rig; and
• Ceasing noise producing activities
within 10 miles (16 km) of the mean
higher high water (MHHW) line of the
Susitna Delta (Beluga River to the Little
Susitna River) between April 15 and
October 15.
Background
The MMPA prohibits the ‘‘take’’ of
marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and
(D) of the MMPA (16 U.S.C. 1361 et
seq.) direct the Secretary of Commerce
(as delegated to NMFS) to allow, upon
request, the incidental, but not
intentional, taking of small numbers of
marine mammals by U.S. citizens who
engage in a specified activity (other than
commercial fishing) within a specified
geographical region if certain findings
are made and either regulations are
issued or, if the taking is limited to
harassment, a notice of a proposed
incidental take authorization may be
provided to the public for review.
Authorization for incidental takings
shall be granted if NMFS finds that the
taking will have a negligible impact on
the species or stock(s) and will not have
an unmitigable adverse impact on the
availability of the species or stock(s) for
taking for subsistence uses (where
relevant). Further, NMFS must prescribe
the permissible methods of taking and
other means of effecting the least
practicable adverse impact on the
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affected species or stocks and their
habitat, paying particular attention to
rookeries, mating grounds, and areas of
similar significance, and on the
availability of such species or stocks for
taking for certain subsistence uses
(referred to in shorthand as
‘‘mitigation’’); and requirements
pertaining to the mitigation, monitoring
and reporting of such takings are set
forth.
NMFS has defined ‘‘negligible
impact’’ in 50 CFR 216.103 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.
The MMPA states that the term ‘‘take’’
means to harass, hunt, capture, kill or
attempt to harass, hunt, capture, or kill
any marine mammal. Except with
respect to certain activities not pertinent
here, the MMPA defines ‘‘harassment’’
as any act of pursuit, torment, or
annoyance which (i) has the potential to
injure a marine mammal or marine
mammal stock in the wild (Level A
harassment); or (ii) has the potential to
disturb a marine mammal or marine
mammal stock in the wild by causing
disruption of behavioral patterns,
including, but not limited to, migration,
breathing, nursing, breeding, feeding, or
sheltering (Level B harassment).
National Environmental Policy Act
To comply with the National
Environmental Policy Act of 1969
(NEPA; 42 U.S.C. 4321 et seq.) and
NOAA Administrative Order (NAO)
216–6A, NMFS must review our
proposed action (i.e., the issuance of an
incidental harassment authorization)
with respect to potential impacts on the
human environment.
Accordingly, NMFS is preparing an
Environmental Assessment (EA) to
consider the environmental impacts
associated with the issuance of the
proposed rule. NMFS’ EA will be made
available at https://
www.fisheries.noaa.gov/national/
marine-mammal-protection/incidentaltake-authorizations-oil-and-gas on the
date of publication of the proposed rule.
We will review all comments
submitted in response to this notice
prior to concluding our NEPA process
or making a final decision on the
rulemaking request.
Summary of Request
On April 17, 2018, NMFS received an
application from Hilcorp requesting
authorization to incidentally take
marine mammals, by Level A and Level
B harassment, incidental to noise
exposure resulting from oil and gas
activities in Cook Inlet, Alaska, from
May 2019 to April 2024. These
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regulations would be valid for a period
of five years. On October 8, 2018, NMFS
deemed the application adequate and
complete.
The use of sound sources such as
those described in the application (e.g.,
seismic airguns) may result in the take
of marine mammals through disruption
of behavioral patterns or may cause
auditory injury of marine mammals.
Therefore, incidental take authorization
under the MMPA is warranted.
Description of Proposed Activity
Overview
The scope of Hilcorp’s Petition
includes four stages of activity,
including exploration, development,
production, and decommissioning
activities within the Applicant’s area of
operations in and adjacent to Cook Inlet
within the Petition’s geographic area
(Figures 3 and 8 in the application).
Table 1 summarizes the planned
activities within the geographic scope of
this Petition, and the following text
describes these activities in more detail.
This section is organized into two
primary areas within Cook Inlet: lower
Cook Inlet (south of the Forelands to
Homer) and middle Cook Inlet (north of
the Forelands to Susitna/Point
Possession).
TABLE 1—SUMMARY OF PLANNED ACTIVITIES INCLUDED IN INCIDENTAL TAKE REGULATIONS (ITR) PETITION
Cook Inlet region
Year(s)
planned
Seasonal timing
Anticipated duration
Anticipated noise sources
Anchor Point 2D seismic survey.
Lower Cook Inlet, Anchor Point to Kasilof.
2021 or 2022 ..
April–October ..............
30 days .......................
Outer Continental Shelf
(OCS) 3D seismic
survey.
OCS geohazard survey
Lower Cook Inlet OCS
2019 ...............
April–June ...................
45–60 days .................
Marine: 1 source vessel with airgun, 1 node
vessel Onshore/Intertidal: Shot holes,
tracked vehicles, helicopters.
1 source vessel with airguns, 2 support vessels, 1 mitigation vessel potentially.
Lower Cook Inlet OCS
2019 or 2020 ..
30 days .......................
OCS exploratory wells
Lower Cook Inlet OCS
2020–2022 .....
Fall 2019 or spring
20202.
April–October ..............
Iniskin Peninsula exploration and development.
Platform & pipeline
maintenance.
Lower Cook Inlet, west
side.
2019–2020 .....
April–October ..............
180 days .....................
Middle Cook Inlet .......
2019–2024 .....
April–October ..............
180 days .....................
North Cook Inlet Unit
subseawell
geohazard survey.
North Cook Inlet Unit
well abandonment
activity.
Trading Bay area
geohazard survey.
Trading Bay area exploratory wells.
Middle Cook Inlet .......
2020 ...............
May .............................
14 days .......................
Middle Cook Inlet .......
2020 ...............
May–July ....................
90 days .......................
1 jack-up rig, tugs towing rig, support vessel,
helicopters.
Middle Cook Inlet .......
2020 ...............
May .............................
30 days .......................
Middle Cook Inlet .......
2020 ...............
May–October ..............
120–150 days .............
Drift River terminal decommissioning.
Lower Cook Inlet, west
side.
2023 ...............
April–October ..............
120 days .....................
1 vessel with echosounders and/or sub-bottom profilers.
1 jack-up rig, drive pipe installation, vertical
seismic profiling, tugs towing rig, support
vessel, helicopters.
Vessels.
Project name
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40–60 days per well,
2–4 wells per year.
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1 vessel with chosounders and/or sub-bottom
profilers.
1 jack-up rig, drive pipe installation, vertical
seismic profiling, 2–3 tugs for towing rig,
support vessels, helicopters.
Construction of causeway, vibratory sheet
pile driving, dredging, vessels.
Vessels, water jets, hydraulic grinders,
pingers, helicopters, and/or sub-bottom
profilers.
1 vessel with echosounders and/or sub-bottom profilers.
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Dates and Duration
The scope of the Petition includes
exploration, development, production,
and decommissioning activities within
the Applicant’s area of operations in
and adjacent to Cook Inlet within the
Petition’s geographic area (Figures 3 and
8 in the application) for the period of
five years beginning May 1, 2019,
extending through April 30, 2024.
Specific Geographic Region
The geographic area of activity covers
a total of approximately 2.7 million
acres (10,926 km2) in Cook Inlet. It
includes land and adjacent waters in
Cook Inlet including both State of
Alaska and Federal OCS waters (Figure
3 and 8 in the application). The area
extends from the north at the Susitna
Delta on the west side (61°10′ 48 N,
151°0′ 55 W) and Point Possession on
the east side (61°2′ 11 N, 150°23′ 30 W)
to the south at Ursus Cove on the west
side (59°26′ 20 N, 153°45′ 5 W) and
Nanwalek on the east side (59°24′ 5 N,
151°56′ 30 W). The area is depicted in
Figures 3 amd 8 of the application.
Detailed Description of Specific Activity
Activities in Lower Cook Inlet
Based on potential future lease sales
in both State and Federal waters,
operators collect two-dimensional (2D)
seismic data to determine the location of
possible oil and gas prospects.
Generally, 2D survey lines are spaced
farther apart than three-dimensional
(3D) surveys and are conducted in a
regional pattern that provides less
detailed geological information. 2D
surveys are used to cover wider areas to
map geologic structures on a regional
scale. Airgun array sizes used during 2D
surveys are similar to those used during
3D surveys.
Activities in Middle Cook Inlet
2D Seismic Survey
During the timeframe of this Petition,
the region of interest for the 2D survey
is the marine, intertidal, and onshore
area on the eastern side of Cook Inlet
from Anchor Point to Kasilof. The area
of interest is approximately 8 km (5
miles) offshore of the coastline. The
anticipated timing of the planned 2D
survey is in the open water season
(April through October) in either 2020
or 2021. The actual survey duration is
approximately 30 days in either year.
The 2D seismic data are acquired
using airguns in the marine zone,
airguns in the intertidal zone when the
tide is high and drilled shot holes in the
intertidal zone when the tide is low and
drilled shot holes in the land zone. The
data are recorded using an autonomous
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nodal system (i.e., no cables) that are
deployed in the marine, intertidal, and
land zones. The planned source lines
(airgun and shot holes) are
approximately 16 km (10 mi) in length
running perpendicular to the coastline
(see Figure 1 in application). The source
lines are spaced every 8 km (5 mi) in
between Anchor Point and Kasilof, with
approximately 9–10 lines over the area
of interest.
In the marine and high tide intertidal
zones, data will be acquired using a
shallow water airgun towed behind one
source vessel. Although the precise
volume of the airgun array is unknown
at this time, Hilcorp will use an airgun
array similar to what has been used for
surveys in Cook Inlet by Apache (2011–
2013) and SAExploration (2015): Either
a 2,400 cubic inch (cui) or 1,760 cui
array. A 2,400 cui airgun was assumed
for analysis in this proposed rule to be
conservative in take estimation. In
addition, the source vessel will be
equipped with a 440 cui shallow water
source which it can deploy at high tide
in the intertidal area in less than 1.8
meter (6 feet) of water. Source lines are
oriented along the node line. A single
vessel is capable of acquiring a source
line in approximately 1–2 hours (hrs). In
general, only one source line will be
collected in one day to allow for all the
node deployments and retrievals, and
intertidal and land zone shot holes
drilling. There are up to 10 source lines,
so if all operations run smoothly, there
will only be 2 hr per day over 10 days
of airgun activity. Hilcorp anticipates
the entire operation to take
approximately 30 days to complete to
account for weather and equipment
contingencies.
The recording system that will be
employed is an autonomous system
‘‘nodal’’ (i.e., no cables), which is
expected to be made up of at least two
types of nodes; one for the land and one
for the intertidal and marine
environment. For the intertidal and
marine zone, this will be a submersible
multi-component system made up of
three velocity sensors and a
hydrophone. These systems have the
ability to record continuous data. Inline
receiver intervals for the node systems
are approximately 50 m (165 ft). For 2D
seismic surveys, the nodes are deployed
along the same line as the seismic
source. The deployment length is
restricted by battery duration and data
storage capacity. The marine nodes will
be placed using one node vessel. The
vessels required for the 2D seismic
survey include just a source vessel and
a node vessel that is conducting only
passive recording.
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In the marine environment, once the
nodes are placed on the seafloor, the
exact position of each node is required.
In very shallow water, the node
positions are either surveyed by a land
surveyor when the tide is low, or the
position is accepted based on the
position at which the navigator has laid
the unit. In deeper water, a hull or pole
mounted pinger to send a signal to the
transponder which is attached to each
node will be used. The transponders are
coded and the crew knows which
transponder goes with which node prior
to the layout. The transponders
response (once pinged) is added
together with several other responses to
create a suite of range and bearing
between the pinger boat and the node.
Those data are then calculated to
precisely position the node. In good
conditions, the nodes can be
interrogated as they are laid out. It is
also common for the nodes to be pinged
after they have been laid out. Onshore
and intertidal locating of source and
receivers will be accomplished with
Differential Global Positioning System/
roving units (DGPS/RTK) equipped with
telemetry radios which will be linked to
a base station established on the source
vessel. Survey crews will have both
helicopter and light tracked vehicle
support. Offshore source and receivers
will be positioned with an integrated
navigation system (INS) utilizing DGPS/
RTK link to the land base stations. The
integrated navigation system will be
capable of many features that are critical
to efficient safe operations. The system
will include a hazard display system
that can be loaded with known
obstructions, or exclusion zones.
Apache conducted a sound source
verification (SSV) for the 440 cui and
2,400 cui arrays in 2012 (Austin and
Warner 2012; 81 FR 47239). The
location of the SSV was in Beshta Bay
on the western side of Cook Inlet
(between Granite Point and North
Forelands). Water depths ranged from
30–70 m (98–229 ft).
For the 440 cui array, the measured
levels for the broadside direction were
217 decibel (dB) re: 1microPa (mPa)
peak, 190 dB sound exposure level
(SEL), and 201 dB root mean square
(rms) at a distance of 50 m. The
estimated distance to the 160 dB rms
(90th percentile) threshold assuming the
empirically measured transmission loss
of 20.4 log R (Austin and Warner, 2012)
was 2,500 m. Sound level near the
source were highest between 30 and 300
hertz (Hz) in the endfire direction and
between 20 Hz and 300 Hz in the
broadside direction.
For the 2,400 cui array, the measured
levels for the endfire direction were 217
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dB peak, 185 dB SEL, and 197 dB rms
at a distance of 100 m. The estimate
distance to the 160 dB rms (90th
percentile) thresholds assuming the
empirically measured transmission loss
of 16.9 log R was 7,770 m. Sound levels
near the source were highest between 30
and 150 Hz in the endfire direction and
between 50 and 200 Hz in the broadside
direction. These measured levels were
used to evaluate potential Level A (217
dB peak and 185 dB SEL at 100 m
assuming 15 log transmission loss) and
Level B (7,330 m distance to 160 dB
threshold) harassment isopleths from
these sound sources (see Estimated Take
section).
3D Seismic Survey
During the timeframe of this Petition,
Hilcorp plans to collect 3D seismic data
for approximately 45–60 days starting
May 1, 2019 over 8 of the 14 OCS lease
blocks in lower Cook Inlet. The 3D
seismic survey is comprised of an area
of approximately 790 km2 (305 mi2)
through 8 lease blocks (6357, 6405,
6406, 6407, 6455, 6456, 6457, 6458).
Hilcorp submitted an application for an
Incidental Harassment Authorization
(IHA) in late 2017 for a planned survey
in 2018 but withdrew the application
and now plan for the survey to take
place in 2019 and cover several years of
surveying and development. The survey
program is anticipated to begin May 1,
2019, and last for approximately 45–60
days through June 2019 in compliance
with identified Bureau of Ocean Energy
Management (BOEM) lease stipulations.
The length of the survey will depend on
weather, equipment, and marine
mammal delays (contingencies of 20
percent weather, 10 percent equipment,
10 percent marine mammal were
assumed in this analysis, or a 40 percent
increase in expected duration to account
for the aforementioned delays).
Polarcus is the intended seismic
contractor, and the general seismic
survey design is provided below. The
3D seismic data will be acquired using
a specially designed marine seismic
vessel towing between 8 and 12 ∼2,400m (1.5 mi) recording cables with a dual
air gun array. The survey will involve
one source vessel, one support vessel,
one chase vessel, and potentially one
mitigation vessel. The anticipated
seismic source to be deployed from the
source vessel is a 14-airgun array with
a total volume of 1,945 cui. Crew
changes are expected to occur every four
to six weeks using a helicopter or
support vessel from shore bases in lower
Cook Inlet. The proposed seismic survey
will be active 24 hrs per day. The array
will be towed at a speed of
approximately 7.41 km/hr (4 knots),
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with seismic data collected
continuously. Data acquisition will
occur for approximately 5 hrs, followed
by a 1.5-hr period to turn and reposition
the vessel for another pass. The turn
radius on the seismic vessel is
approximately 3,200 m (2 mi).
The data will be shot parallel to the
Cook Inlet shorelines in a north/south
direction. This operational direction
will keep recording equipment/
streamers in line with Cook Inlet
currents and tides and keep the
equipment away from shallow waters on
the east and west sides. The program
may be modified if the survey cannot be
conducted as a result of noise
conditions onsite (i.e., ambient noise).
The airguns will typically be turned off
during the turns. However, depending
on the daylight hours and length of the
turn, Hilcorp may use the smallest gun
in the array (45 cui) as a mitigation
airgun where needed for no longer than
3 hours. The vessel will turn into the
tides to ensure the recording cables/
streamers remain in line behind the
vessel.
Hilcorp plans to use an array that
provides for the lowest possible sound
source to collect the target data. The
proposed array is a Bolt 1900 LLXT dual
gun array. The airguns will be
configured as two linear arrays or
‘‘strings;’’ each string will have 7
airguns shooting in a ‘‘flip-flop’’
configuration for a total of 14 airguns.
The airguns will range in volume from
45 to 290 cui for a total of 1,945 cui. The
first and last are spaced approximately
14 m (45.9 ft) apart and the strings are
separated by approximately 10 m (32.8
ft). The two airgun strings will be
distributed across an approximate area
of 30 x 14 m (98.4 x 45.9 ft) behind the
source vessel and will be towed 300–
400 m (984–1,312 ft) behind the vessel
at a depth of 5 m (16.4 ft). The firing
pressure of the array is 2,000 pounds
per square inch (psi). The airgun will
fire every 4.5 to 6 seconds, depending
on the exact speed of the vessel. When
fired, a brief (25 milliseconds [ms] to
140 ms) pulse of sound is emitted by all
airguns nearly simultaneously. Hilcorp
proposes to use a single 45 cui airgun,
the smallest airgun in the array, for
mitigation purposes.
Hilcorp intends to use 8 Sercel-type
solid streamers or functionally similar
for recording the seismic data (Figure 5
in the application). Each streamer will
be approximately 2,400 m (150 mi) in
length and will be towed approximately
8–15 m (26.2–49.2 ft) or deeper below
the surface of the water. The streamers
will be placed approximately 50 m (165
ft) apart to provide a total streamer
spread of 400 m (1,148 ft). Hilcorp
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recognizes solid streamers as best in
class for marine data acquisition
because of unmatched reliability, signal
to noise ratio, low frequency content,
and noise immunity.
The survey will involve one source
vessel, one support vessel, one or two
chase vessels, and potentially one
mitigation vessel. The source vessel
tows the airgun array and the streamers.
The support vessel provides general
support for the source vessel, including
supplies, crew changes, etc. The chase
vessel monitors the in-water equipment
and maintains a security perimeter
around the streamers. The mitigation
vessel provides a viewing platform to
augment the marine mammal
monitoring program.
The planned volume of the airgun
array is 1,945 cui. Hilcorp and their
partners will be conducting detailed
modeling of the array output, but a
detailed SSV has not been conducted for
this array in Cook Inlet. Therefore, for
the purposes of estimating acoustic
harassment, results from previous
seismic surveys in Cook Inlet by Apache
and SAExploration, particularly the
2,400 cui array, were used. Apache
conducted an SSV for the 440 cui and
2,400 cui arrays in 2012 (Austin and
Warner 2012; 81 FR 47239). The
location of the SSV was in Beshta Bay
on the western side of Cook Inlet
(between Granite Point and North
Forelands). Water depths ranged from
30–70 m (98–229 ft). For the 2,400 cui
array, the measured levels for the
endfire direction were 217 dB peak, 185
dB SEL, and 197 dB rms at a distance
of 100 m. The estimate distance to the
160 dB rms (90th percentile) thresholds
assuming the empirically measured
transmission loss of 16.9 log R was
7,770 m. Sound levels near the source
were highest between 30 and 150 Hz in
the endfire direction and between 50
and 200 Hz in the broadside direction.
These measured levels were used to
evaluate potential Level A (217 dB peak
and 185 dB SEL at 100 m assuming 15
log transmission loss) and B (7,330 m
distance to 160 dB threshold) acoustic
harassment of marine mammals in this
Petition.
Geohazard and Geotechnical Surveys
Upon completion of the 3D seismic
survey over the lower Cook Inlet OCS
leases, Hilcorp plans to conduct a
geohazard survey on site-specific
regions within the area of interest prior
to conducting exploratory drilling. The
precise location is not known, as it
depends on the results of the 3D seismic
survey, but the location will be within
the lease blocks. The anticipated timing
of the activity is in either the fall of 2019
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or the spring of 2020. The actual survey
duration will take approximately 30
days.
The suite of equipment used during a
typical geohazards survey consists of
single beam and multi-beam
echosounders, which provide water
depths and seafloor morphology; a side
scan sonar that provides acoustic images
of the seafloor; a sub-bottom profiler
which provides 20 to 200 m (66 to 656
ft) sub-seafloor penetration with a 6- to
20-centimeter (cm, 2.4–7.9-inch [in])
resolution. Magnetometers, to detect
ferrous items, may also be used.
Geotechnical surveys are conducted to
collect bottom samples to obtain
physical and chemical data on surface
and near sub-surface sediments.
Sediment samples typically are
collected using a gravity/piston corer or
grab sampler. The surveys are
conducted from a single support vessel.
The echosounders and sub-bottom
profilers are generally hull-mounted or
towed behind a single vessel. The ship
travels at 3–4.5 knots (5.6–8.3 km/hr).
Surveys are site specific and can cover
less than one lease block in a day, but
the survey extent is determined by the
number of potential drill sites in an
area. BOEM guidelines at NTL–A01
require data to be gathered on a 150 by
300 m (492 by 984 ft) grid within 600
m (1,969 ft) of the surface location of the
drill site, a 300 by 600 m (984 by 1,969
ft) grid along the wellbore path out to
1,200 m (3,937 ft) beyond the surface
projection of the conductor casing, and
extending an additional 1,200 m beyond
that limit with a 1,200 by 1,200 m grid
out to 2,400 m (7,874 ft) from the well
site.
The multibeam echosounder, single
beam echosounder, and side scan sonar
operate at frequencies of greater than
200 kHz. Based on the frequency ranges
of these pieces of equipment and the
hearing ranges of the marine mammals
that have the potential to occur in the
action area, the noise produced by the
echosounders and side scan sonar are
not likely to result in take of marine
mammals and are not considered further
in this document.
The geophysical surveys include use
of a low resolution and high resolution
sub-bottom profiler. The proposed highresolution sub-bottom profiler operates
at source level of 210 dB re 1 mPa RMS
at 1 m. The proposed system emits
energy in the frequency bands of 2 to 24
kHz. The beam width is 15 to 24
degrees. Typical pulse rate is between 3
and 10 Hz. The secondary lowresolution sub-bottom profiler will be
utilized as necessary to increase subbottom profile penetration. The
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proposed system emits energy in the
frequency bands of 1 to 4 kHz.
Exploratory Drilling
Operators will drill exploratory wells
based on mapping of subsurface
structures using 2D and 3D seismic data
and historical well information. Hilcorp
plans to conduct the exploratory drilling
program April to October between 2020
and 2022. The exact start date is
currently unknown and is dependent on
the results of the seismic survey,
geohazard survey, and scheduling
availability of the drill rig. It is expected
that each well will take approximately
40–60 days to drill and test. Beginning
in spring 2020, Hilcorp Alaska plans to
possibly drill two and as many as four
exploratory wells, pending results of the
3D seismic survey in the lower Cook
Inlet OCS leases. After testing, the wells
may be plugged and abandoned.
Hilcorp Alaska proposes to conduct
its exploratory drilling using a rig
similar to the Spartan 151 drill rig. The
Spartan 151 is a 150 H class
independent leg, cantilevered jack-up
drill rig with a drilling depth capability
of 7,620 m (25,000 ft) that can operate
in maximum water depths up to 46 m
(150 ft). Depending on the rig selection
and location, the drilling rig will be
towed on site using up to three oceangoing tugs licensed to operate in Cook
Inlet. Rig moves will be conducted in a
manner to minimize any potential risk
regarding safety as well as cultural or
environmental impact. While under tow
to the well sites, rig operations will be
monitored by Hilcorp and the drilling
contractor management. Very High
Frequency (VHF) radio, satellite, and
cellular phone communication systems
will be used while the rig is under tow.
Helicopter transport will also be
available.
Similarly to transiting vessels,
although some marine mammals could
receive sound levels in exceedance of
the general acoustic threshold of 120 dB
from the tugs towing the drill rig during
this project, take is unlikely to occur,
primarily because of the predictable
movement of vessels and tugs. Marine
mammal population density in the
project area is low (see Estimated Take
section below), and those that are
present are likely habituated to the
existing baseline of commercial ship
traffic. Further, there are no activity-,
location-, or species-specific
circumstances or other contextual
factors that would increase concern and
the likelihood of take from towing of the
drill rig.
The drilling program for the well will
be described in detail in an Exploration
Plan to BOEM. The Exploration Plan
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will present information on the drilling
mud program; casing design, formation
evaluation program; cementing
programs; and other engineering
information. After rig up/rig acceptance
by Hilcorp Alaska, the wells will be
spudded and drilled to bottom-hole
depths of approximately 2,100 to 4,900
m (7,000 to 16,000 ft) depending on the
well. It is expected that each well will
take about 40–60 days to drill and up to
10–21 days of well testing. If two wells
are drilled, it will take approximately
80–120 days to complete the full
program; if four wells are drilled, it will
take approximately 160–240 days to
complete the full program.
Primary sources of rig-based acoustic
energy were identified as coming from
the D399/D398 diesel engines, the PZ–
10 mud pump, ventilation fans (and
associated exhaust), and electrical
generators. The source level of one of
the strongest acoustic sources, the diesel
engines, was estimated to be 137 dB re
1 mPa rms at 1 m in the 141–178 Hz
bandwidth. Based on this measured
level, the 120 dB rms acoustic received
level isopleth would be 50 m (154 ft)
away from where the energy enters the
water (jack-up leg or drill riser). Drilling
and well construction sounds are
similar to vessel sounds in that they are
relatively low-level and low-frequency.
Since the rig is stationary in a location
with low marine mammal density, the
impact of drilling and well construction
sounds produced from the jack up rig is
expected to be lower than a typical large
vessel. There is open water in all
directions from the drilling location.
Any marine mammal approaching the
rig would be fully aware of its presence
long before approaching or entering the
zone of influence for behavioral
harassment, and we are unaware of any
specifically important habitat features
(e.g., concentrations of prey or refuge
from predators) within the rig’s zone of
influence that would encourage marine
mammal use and exposure to higher
levels of noise closer to the source.
Given the absence of any activity-,
location-, or species-specific
circumstances or other contextual
factors that would increase concern, we
do not expect routine drilling noise to
result in the take of marine mammals.
When planned and permitted
operations are completed, the well will
be suspended according to Bureau of
Safety and Environmental Enforcement
(BSEE) regulations. The well casings
will be landed in a mudline hanger after
each hole section is drilled. When the
well is abandoned, the production
casing is sealed with mechanical
plugging devices and cement to prevent
the movement of any reservoir fluids
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between various strata. Each casing
string will be cutoff below the surface
and sealed with a cement plug. A final
shallow cement plug will be set to
approximately 3.05 m (10 ft) below the
mudline. At this point, the surface
casing, conductor, and drive pipe will
be cutoff and the three cutoff casings
and the mudline hanger are pulled to
the deck of the jack-up rig for final
disposal. The plugging and
abandonment procedures are part of the
Well Plan which is reviewed by BSEE
prior to being issued an approved
Permit to Drill.
A drive pipe is a relatively short,
large-diameter pipe driven into the
sediment prior to the drilling of oil
wells. The drive pipe serves to support
the initial sedimentary part of the well,
preventing the looser surface layer from
collapsing and obstructing the wellbore.
Drive pipes are installed using pile
driving techniques. Hilcorp proposed to
drive approximately 60 m of 76.2-cm
pipe at each well site prior to drilling
using a Delmar D62–22 impact hammer
(or similar). This hammer has an impact
weight of 6,200 kg (13,640 lbs). The
drive pipe driving event is expected to
last one to three days at each well site,
although actual pounding of the pipe
will only occur intermittently during
this period. Conductors are slightly
smaller diameter pipes than the drive
pipes used to transport or ‘‘conduct’’
drill cuttings to the surface. For these
wells, a 50.8-cm [20-in] conductor pipe
may be drilled, not hammered, inside
the drive pipe, dependent on the
integrity of surface formations.
Illingworth & Rodkin (2014) measured
the hammer noise for hammering the
drive pipe operating from the rig
Endeavour for Buccaneer in 2013 and
report the source level at 190 dB at 55
m, with underwater levels exceeding
160 dB rms threshold at 1.63 km (1 mi).
The measured sound levels for the pipe
driving were used to evaluate potential
Level A (source level of 221dB @1m and
assuming 15 logR transmission loss) and
Level B (1,630 m distance to the 160 dB
threshold) acoustic harassment of
marine mammals. Conductors are
slightly smaller diameter pipes than the
drive pipes used to transport or
‘‘conduct’’ drill cuttings to the surface.
For these wells, a 50.8-cm (20-in)
conductor pipe may be drilled, not
hammered, inside the drive pipe,
dependent on the integrity of surface
formations. There are no noise concerns
associated with the conductor pipe
drilling.
Once the well is drilled, accurate
follow-up seismic data may be collected
by placing a receiver at known depths
in the borehole and shooting a seismic
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airgun at the surface near the borehole,
called vertical seismic profiling (VSP).
These data provide high-resolution
images of the geological layers
penetrated by the borehole and can be
used to accurately correlate original
surface seismic data. The actual size of
the airgun array is not determined until
the final well depth is known, but
typical airgun array volumes are
between 600 and 880 cui. VSP typically
takes less than two full days at each well
site. Illingworth & Rodkin (2014)
measured a 720 cui array for Buccaneer
in 2013 and report the source level at
227 dB at 1 m, with underwater levels
exceeding 160 dB rms threshold at 2.47
km (1.54 mi). The measured sound
levels for the VSP were used to evaluate
potential Level A (227 dB rms at 1 m
assuming 15 logR transmission loss) and
Level B (2,470 m distance to the 160 dB
threshold) harassment isopleths.
Iniskin Peninsula Exploration
Hilcorp Alaska initiated baseline
exploratory data collection in 2013 for
a proposed land-based oil and gas
exploration and development project on
the Iniskin Peninsula of Alaska, near
Chinitna Bay. The proposed project is
approximately 97 km (60 mi) west of
Homer on the west side of Cook Inlet in
the Fitz Creek drainage. New project
infrastructure includes material sites, a
6.9 km (4.3 mi) long access road,
prefabricated bridges to cross four
streams, an air strip, barge landing/
staging areas, fuel storage facilities,
water wells and extraction sites, an
intertidal causeway, a camp/staging
area, and a drill pad. Construction is
anticipated to start in 2020.
An intertidal rock causeway is
proposed to be constructed adjacent to
the Fitz Creek staging area to improve
the accessibility of the barge landing
during construction and drilling
operations. The causeway will extend
seaward from the high tide line
approximately 366 m (1,200 ft) to a
landing area 46 m (150 ft) wide. A dock
face will be constructed around the rock
causeway so that barges will be able to
dock along the causeway. Rock
placement for the causeway is not
known to generate sound at levels
expected to disturb marine mammals.
The causeway is also not proposed at a
known pinniped haulout or other
biologically significant location for local
marine mammals. Therefore, rock laying
for the causeway is not considered
further in this document.
The causeway will need to be 75
percent built before the construction of
the dock face will start. The dock face
will be constructed with 18-m (60-ft) tall
Z-sheet piles, all installed using a
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vibratory hammer. It will take
approximately 14–25 days, depending
on the length of the work shift,
assuming approximately 25 percent of
the day actual pile driving. The timing
of pile driving will be in late summer or
early winter, after the causeway has
been partially constructed. Illingworth &
Rodkin (2007) compiled measured nearsource (10 m [32.8 ft]) SPL data from
vibratory pile driving for different pile
sizes ranging in diameter from 30.5 to
243.8 cm (12 to 96 in). For this petition,
the source level of the 61.0-cm (24-in)
AZ steel sheet pile from Illingworth &
Rodkin (2007) was used for the sheet
pile. The measured sound levels of 160
dB rms at 10 m assuming 15 logR
transmission loss for the vibratory sheet
pile driving was used to evaluate
potential Level A and B harassment
isopleths.
Activities in Middle Cook Inlet
Offshore Production Platforms
Of the 17 production platforms in
central Cook Inlet, 15 are owned by
Hilcorp. Hilcorp performs routine
construction on their platforms,
depending on needs of the operations.
Construction activities may take place
up to 24 hrs a day. In-water activities
include support vessels bringing
supplies five days a week up to two
trips per day between offshore systems
at Kenai (OSK) and the platform.
Depending on the needs, there may also
be barges towed by tugs with equipment
and helicopters for crew and supply
changes. Routine supply-related transits
from vessels and helicopters are not
substantially different from routine
vessel and air traffic already occurring
in Cook Inlet, and take is not expected
to occur from these activities.
Offshore Production Drilling
Hilcorp routinely conducts
development drilling activities at
offshore platforms on a regular basis to
meet the asset’s production needs.
Development drilling activities occurs
from existing platforms within the Cook
Inlet through either open well slots or
existing wellbores in existing platform
legs. Drilling activities from platforms
within Cook Inlet are accomplished by
using conventional drilling equipment
from a variety of rig configurations.
Some other platforms in Cook inlet
have permanent drilling rigs installed
that operate under power provided by
the platform power generation systems,
while others do not have drill rigs, and
the use of a mobile drill rig is required.
Mobile offshore drill rigs may be
powered by the platform power
generation (if compatible with the
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platform power system) or self-generate
power with the use of diesel fired
generators. For the reasons outlined
above for the Lower Inlet, noise from
routine drilling is not considered further
in this document.
Helicopter logistics for development
drilling programs operations will
include transportation for personnel and
supplies. The helicopter support will be
managed through existing offshore
services based at the OSK Heliport to
support rig crew changes and cargo
handling. Helicopter flights to and from
the platform while drilling is occurring
is anticipated to increase (on average) by
two flights per day from normal
platform operations.
Major supplies will be staged onshore at the OSK Dock in Nikiski.
Required supplies and equipment will
be moved from the staging area to the
platform in which drilling occurring by
existing supply vessels that are
currently in use supporting offshore
operations within Cook Inlet. Vessel
trips to and from the platform while
drilling is occurring is anticipated to
increase (on average) by two trips per
day from normal platform operations.
During mobile drill rig mobilization and
demobilization, one support vessel is
used continuously for approximately 30
days to facilitate moving rig equipment
and materials.
Oil and Gas Pipeline Maintenance
Each year, Hilcorp Alaska must verify
the structural integrity of their platforms
and pipelines located within Cook Inlet.
Routine maintenance activities include:
subsea pipeline inspections,
stabilizations, and repairs; platform leg
inspections and repairs; and anode sled
installations and/or replacement. In
general, pipeline stabilization and
pipeline repair are anticipated to occur
in succession for a total of 6–10 weeks.
However, if a pipeline stabilization
location also requires repair, the divers
will repair the pipeline at the same time
they are stabilizing it. Pipeline repair
activities are only to be conducted on an
as-needed basis whereas pipeline
stabilization activities will occur
annually. During underwater
inspections, if the divers identify an
area of the pipeline that requires
stabilization, they will place Sea-Crete
bags at that time rather than waiting
until the major pipeline stabilization
effort that occurs later in the season.
Natural gas and oil pipelines located
on the seafloor of the Cook Inlet are
inspected on an annual basis using
ultrasonic testing (UT), cathodic
protection surveys, multi-beam sonar
surveys, and sub-bottom profilers.
Deficiencies identified are corrected
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using pipeline stabilization methods or
USDOT-approved pipeline repair
techniques. The Applicant employs dive
teams to conduct physical inspections
and evaluate cathodic protection status
and thickness of subsea pipelines on an
annual basis. If required for accurate
measurements, divers may use a water
jet to provide visual access to the
pipeline. For stabilization, inspection
dive teams may place Sea-Crete bags
beneath the pipeline to replace any
materials removed by the water jet.
Results of the inspections are recorded
and significant deficiencies are noted
for repair.
Multi-beam sonar and sub-bottom
profilers may also be used to obtain
images of the seabed along and
immediately adjacent to all subsea
pipelines. Elements of pipeline
inspections that could produce
underwater noise include: the dive
support vessel, water jet, multi-beam
sonar/sub-bottom profiler and
accompanying vessel.
A water jet is a zero-thrust water
compressor that is used for underwater
removal of marine growth or rock debris
underneath the pipeline. The system
operates through a mobile pump which
draws water from the location of the
work. Water jets likely to be used in
Cook Inlet include, but are not limited
to, the CaviDyne CaviBlaster® and the
Gardner Denver Liqua-Blaster. Noise
generated during the use of the water
jets would be very short in duration (30
minutes or less at any given time) and
intermittent.
Hilcorp Alaska conducted underwater
measurements during 13 minutes of
CaviBlaster® use in Cook Inlet in April
2017 (Austin 2017). Received sound
levels were measured up to 143 dB re
1 mPa rms at 170 m and up to 127 dB
re 1 mPa rms at 1,100 m. Sounds from
the Caviblaster® were clearly detectable
out to the maximum measurement range
of 1.1 km. Using the measured
transmission loss of 19.5 log R (Austin
2017), the source level for the
Caviblaster® was estimated as 176 dB re
1 mPa at 1 m. The sounds were
broadband in nature, concentrated
above 500 Hz with a dominant tone near
2 kHz.
Specifications for the GR 29
Underwater Hydraulic Grinder state that
the SPL at the operator’s position would
be 97 dB in air (Stanley 2014). There are
no underwater measurements available
for the grinder, so using a rough
estimate of converting sound level in dB
in air to water by adding 61.5 dB would
result in an underwater level of
approximately 159 dB2. The measured
sound levels for the water jet and
grinder were used to evaluate potential
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Level A and B acoustic harassment
isopleths.
If necessary, Hilcorp may use an
underwater pipe cutter to replace
existing pipeline segments in Cook
Inlet. The following tools are likely to be
used for pipeline cutting activities:
• A diamond wire saw used for
remote cutting underwater structures
such as pipes and I-Beams. These saws
use hydraulic power delivered by a
dedicated power source. The saw
usually uses a method that pushes the
spinning wire through the pipe.
• A hydraulically-powered Guillotine
saw which uses an orbital cutting
movement similar to traditional power
saws.
Generally, sound radiated from the
diamond wire cutter is not easily
discernible from the background noise
during the cutting operation. The Navy
measured underwater sound levels
when the diamond saw was cutting
caissons for replacing piles at an old
fuel pier at Naval Base Point Loma
(Naval Base Point Loma Naval Facilities
Engineering Command Southwest
2017). They reported an average SPL for
a single cutter at 136.1–141.4 dB rms at
10 m.
Specifications for the Guillotine saw
state that the SPL at the operator’s
position would be 86 dB in air (Wachs
2014). There are no underwater
measurements available for the grinder,
so using a rough estimate of converting
sound level in dB in air to water by
adding 61.5 dB would result in an
underwater level of approximately 148
dB.
Because the measured levels for use of
underwater saws do not exceed the
NMFS criteria, the noise from
underwater saws was not considered
further in this document. Scour spans
beneath pipelines greater than 23 m (75
ft) have the potential to cause pipeline
failures. To be conservative, scour spans
of 15 m (50 ft) or greater identified using
multi-beam sonar surveys are
investigated using dive teams. Divers
perform tactile inspections to confirm
spans greater than 15 m (50 ft). The
pipeline is stabilized along these spans
with Sea-Crete concrete bags. While in
the area, the divers will also inspect the
external coating of the pipeline and take
cathodic protection readings if corrosion
wrap is found to be absent. Elements of
pipeline stabilization that could
produce underwater noise include: Dive
support vessel and water jet.
Significant pipeline deficiencies
identified during pipeline inspections
are repaired as soon as practicable using
methods including, but not limited to,
USDOT-approved clamps and/or fiber
glass wraps, bolt/flange replacements,
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and manifold replacements. In some
cases, a water jet may be required to
remove sand and gravel from under or
around the pipeline to allow access for
assessment and repair. The pipeline
surface may also require cleaning using
a hydraulic grinder to ensure adequate
repair. If pipeline replacement is
required, an underwater pipe cutter
such as a diamond wire saw or
hydraulically-powered Guillotine saw
may be used. Elements of pipeline
repair that could produce underwater
noise include: Dive support vessel,
water jet, hydraulic grinder, and
underwater pipe cutter.
Platform Leg Inspection and Repair
Hilcorp’s platforms in Cook Inlet are
inspected on a routine basis. Divers and
certified rope access technicians
visually inspect subsea platform legs.
These teams also identify and correct
significant structural deficiencies.
Platform leg integrity and pipeline-toplatform connections beneath the water
surface are evaluated by divers on a
routine basis. Platform legs, braces, and
pipeline-to-platform connections are
evaluated for cathodic protection status,
structure thickness, excessive marine
growth, damage, and scour. If required,
divers may use a water jet to clean or
provide access to the structure. If
necessary, remedial grinding using a
hydraulic under water grinder may be
required to determine extent damage
and/or to prevent further crack
propagation. All inspection results are
recorded and significant deficiencies are
noted for repair. Elements of subsea
platform leg inspection and repair that
could produce underwater noise
include: Dive support vessel, hydraulic
grinder, water jet.
Platform leg integrity along the tidal
zone is inspected on a routine basis.
Difficult-to-reach areas may be accessed
using either commercially-piloted
unmanned aerial systems (UAS).
Commercially-piloted UASs may be
deployed from the top-side of the
platform to obtain images of the legs.
Generally, the UAS is in the air for 15–
20 minutes at a time due to battery
capacity, which allows for two legs and
part of the underside of the platform to
be inspected. The total time to inspect
a platform is approximately 1.5 hrs of
flight time. The UAS is operated at a
distance of up to 30.5 m (100 ft) from
the platform at an altitude of 9–15 m
(30–50 ft) above sea level. To reduce
potential harassment of marine
mammals, the area around the platform
would be inspected prior to launch of
the UAS to ensure there are no flights
directly above marine mammals. As no
flights will be conducted directly over
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marine mammals, the effects of drone
use for routine maintenance are not
considered further in this application.
Anode Sled Installation and
Replacement
Galvanic and impressed current
anode sleds are used to provide
cathodic protection for the pipelines
and platforms in Cook Inlet. Galvanic
anode sleds do not require a power
source and may be installed along the
length of the pipelines on the seafloor.
Impressed current anode sleds are
located on the seafloor at each of the
corners of each platform and are
powered by rectifiers located on the
platform. Anodes are placed at the
seafloor using dive vessels and hand
tools. If necessary, a water jet may be
used to provide access for proper
installation. Anodes and/or cables may
be stabilized using Sea-Crete bags.
Pingers
Several types of moorings are
deployed in support of Hilcorp
operations; all of which require an
acoustic pinger for location or release.
The pinger is deployed over the side of
a vessel and a short signal is emitted to
the mooring device. The mooring device
responds with a short signal to indicate
that the device is working, to indicate
range and bearing data, or to illicit a
release of the unit from the anchor.
These are used for very short periods of
time when needed.
The types of moorings requiring the
use of pingers anticipated to be used in
the Petition period include acoustic
moorings during the 3D seismic survey
(assumed 2–4 moorings), node
placement for the 2D survey (used with
each node deployment), and potential
current profilers deployed each season
(assumed 2–4 moorings). The total
amount of time per mooring device is
less than 10 minutes during deployment
and retrieval. To avoid disturbance, the
pinger would not be deployed if marine
mammals have been observed within
135 m (443 ft) of the vessel. The short
duration of the pinger deployment as
well as Hilcorp’s mitigation suggests
take of marine mammals from pinger
use is unlikely to occur and pingers are
not considered further in this analysis.
North Cook Inlet Unit Subsea Well
Plugging and Abandonment
The discovery well in the North Cook
Inlet Unit was drilled over 50 years ago
and is planned to be abandoned, so
Hilcorp Alaska plans to conduct a
geohazard survey to locate the well and
conduct plugging and abandonment
(P&A) activities for a previously drilled
subsea exploration well in 2020. The
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geohazard survey location is
approximately 402–804 m (1⁄4-1⁄2 mi)
south of the Tyonek platform and will
take place over approximately seven
days with a grid spacing of
approximately 250 m (820 ft). The suite
of equipment used during a typical
geohazards survey consists of single
beam and multi-beam echosounders,
which provide water depths and
seafloor morphology; a side scan sonar
that provides acoustic images of the
seafloor; a sub-bottom profiler which
provides 20 to 200 m (66 to 656 ft) subseafloor penetration with a 6- to 20-cm
(2.4–7.9-in) resolution. The
echosounders and sub-bottom profilers
are generally hull-mounted or towed
behind a single vessel. The vessel
travels at 3–4.5 knots (5.6–8.3 km/hr).
After the well has been located,
Hilcorp plans to conduct plugging and
abandonment activities over a 60–90
day time period in May through July in
2020. The jack-up rig will be similar to
what is described above (the Spartan
151 drill rig, or similar). The rig will be
towed onsite using up to three oceangoing tugs. Once the jack-up rig is on
location, divers working off a boat will
assist in preparing the subsea wellhead
and mudline hanger for the riser to tie
the well to the jack-up. Once the riser
is placed, the BOP equipment is made
up to the riser. At this point, the well
will be entered and well casings will be
plugged with mechanical devices and
cement and then cutoff and pulled. A
shallow cement plug will be set in the
surface casing to 3.05 m (10 ft) below
the mudline hanger. The remaining well
casings will be cutoff and the mudline
hanger will be recovered to the deck of
the jack-up rig for disposal. The well
abandonment will be performed in
accordance to Alaska Oil and Gas
Conservation Commission (AOGCC)
regulations.
Trading Bay Exploratory Drilling
Hilcorp plans to conduct exploratory
drilling activities in the Trading Bay
area. The specific sites of interest have
not yet been identified, but the general
area is shown in Figure 3 in the
application. Hilcorp will conduct
geohazard surveys over the areas of
interest to locate potential hazards prior
to drilling with the same suite of
equipment as described above for
exploratory drilling in the lower Inlet.
The survey is expected to take place
over 30–60 days in 2019 from a single
vessel.
The exploratory drilling and well
completion activities will take place in
site-specific areas based on the
geohazard survey. Hilcorp plans to drill
1–2 exploratory wells in this area in the
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open water season of 2020 with the
same equipment and methods as
described above for lower Inlet
exploratory drilling. The noise of
routine drilling is not considered further
as explained in the description of
activities in the Lower Inlet. However,
drive pipe installation and vertical
seismic profiling will be considered
further.
Proposed mitigation, monitoring, and
reporting measures are described in
detail later in this document (please see
Proposed Mitigation and Proposed
Monitoring and Reporting).
Description of Marine Mammals in the
Area of Specified Activities
Eleven species of marine mammal
have the potential to occur in the action
area during the five year period of
activities proposed by Hilcorp. These
species are described in further detail
below.
Fin Whales
For management purposes, three
stocks of fin whales are currently
recognized in U.S. Pacific waters:
Alaska (Northeast Pacific), California/
Washington/Oregon, and Hawaii.
Recent analyses provide evidence that
the population structure should be
reviewed and possibly updated.
However, substantially new data on the
stock structure is lacking (Muto et al.
2017). Fin whales, including the
Northeastern Pacific stock, are listed as
endangered under the ESA.
Mizroch et al. (2009) provided a
comprehensive summary of fin whale
sightings data, including whaling catch
data and determined there could be at
least six populations of fin whales.
Evidence suggests two populations are
migratory (eastern and western North
Pacific) and two to four more are yearround residents in peripheral seas such
as the Gulf of California, East China Sea,
Sanriku-Hokkaido, and possibly the Sea
of Japan. The two migratory stocks are
likely mingling in the Bering Sea in July
and August. Moore et al. (1998, 2006),
Watkins et al. (2000), and Stafford et al.
(2007) documented high rates of calling
along the Alaska coast beginning in
August/September and lasting through
February. Fin whales are regularly
observed in the Gulf of Alaska during
the summer months, even though calls
are seldom detected during this period
(Stafford et al. 2007). Instruments
moored in the southeast Bering Sea
detected calls over the course of a year
and found peaks from September to
November as well as in February and
March (Stafford et al. 2010). Delarue et
al. (2013) detected calls in the
northeastern Chukchi Sea from
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instruments moored from July through
October from 2007 through 2010.
Fin whales are found seasonally in
the Gulf of Alaska, Bering Sea, and as
far north as the northern Chukchi Sea
(Muto et al. 2017). Surveys conducted
in coastal waters of the Aleutians and
the Alaska Peninsula found that fin
whales occurred primarily from the
Kenai Peninsula to the Shumagin
Islands and were abundant near the
Semidi Islands and Kodiak Island
(Zerbini et al. 2006). An opportunistic
survey conducted on the shelf of the
Gulf of Alaska found fin whales
concentrated west of Kodiak Island in
Shelikof Strait, and in the southern
Cook Inlet region. Smaller numbers
were also observed over the shelf east of
Kodiak to Prince William Sound (AFSC,
2003). In the northeastern Chukchi Sea,
visual sightings and acoustic detections
have been increasing, which suggests
the stock may be re-occupying habitat
used prior to large-scale commercial
whaling (Muto et al. 2017). Most of
these areas are feeding habitat for fin
whales. Fin whales are rarely observed
in Cook Inlet, and most sightings occur
near the entrance of the inlet. During the
NMFS aerial surveys in Cook Inlet from
2000–2016, 10 sightings of 26 estimated
individual fin whales in lower Cook
Inlet were observed (Shelden et al.
2013, 2015, 2016).
Humpback Whales
Currently, three populations of
humpback whales are recognized in the
North Pacific, migrating between their
respective summer/fall feeding areas
and winter/spring calving and mating
areas as follows (Baker et al. 1998;
Calambokidis et al. 1997). Although
there is considerable distributional
overlap in the humpback whale stocks
that use Alaska, the whales seasonally
found in lower Cook Inlet are probably
of the Central North Pacific stock (Muto
et al. 2017). Listed as endangered under
the ESA, this stock has recently been
estimated at 7,890 animals (Muto et al.
2017). The Central North Pacific stock
winters in Hawaii and summers from
British Columbia to the Aleutian Islands
(Calambokidis et al. 1997), including
Cook Inlet.
Humpback whales in the high
latitudes of the North Pacific Ocean are
seasonal migrants that feed on
euphausiids and small schooling fishes
(Muto et al. 2017). During the spring,
these animals migrate north and spend
the summer feeding in the prey-rich
sub-polar waters of southern Alaska,
British Columbia, and the southern
Chukchi Sea. Individuals from the
Western North Pacific (endangered),
Hawaii (not listed under the ESA), and
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the Mexico (threatened) DPSs migrate to
areas near and potentially in the
Petition region. However, most of the
individuals that migrate to the Cook
Inlet area are likely from the Hawaii
DPS and not the Western North Pacific
or Mexico DPSs (NMFS 2017).
In the summer, humpback whales are
regularly present and feeding in the
Cook Inlet region, including Shelikof
Strait, Kodiak Island bays, and the
Barren Islands, in addition to Gulf of
Alaska regions adjacent to the southeast
side of Kodiak Island (especially
Albatross Banks), the Kenai and Alaska
peninsulas, Elizabeth Island, as well as
south of the Aleutian Islands.
Humpbacks also may be present in some
of these areas throughout autumn (Muto
et al. 2017).
Humpback whales have been
observed during marine mammal
surveys conducted in Cook Inlet.
However, their presence is largely
confined to lower Cook Inlet. Recent
monitoring by Hilcorp in upper Cook
Inlet has also included sightings of
humpbacks near Tyonek. During
SAExploration’s 2015 seismic program,
three humpback whales were observed
in Cook Inlet; two near the Forelands
and one in Kachemak Bay (Kendall et al.
2015). During NMFS’ Cook Inlet beluga
whale aerial surveys from 2000–2016,
there were 88 sightings of 191 estimated
individual humpback whales in lower
Cook Inlet (Shelden et al. 2017). They
have been regularly seen near Kachemak
Bay during the summer months (Rugh et
al. 2005). There are observations of
humpback whales as far north as
Anchor Point, with recent summer
observations extending to Cape
Starichkof (Owl Ridge 2014). Although
several humpback whale sightings
occurred mid-inlet between Iniskin
Peninsula and Kachemak Bay, most
sightings occurred outside of the
Petition region near Augustine, Barren,
and Elizabeth Islands (Shelden et al.
2013, 2015, 2017).
Ferguson et al. (2015) has established
Biologically Important Areas (BIAs) as
part of the NOAA Cetacean Density and
Distribution Mapping Working Group
(CetMap) efforts. This information
supplements the quantitative
information on cetacean density,
distribution, and occurrence by: (1)
Identifying areas where cetacean species
or populations are known to concentrate
for specific behaviors, or be rangelimited, but for which there is not
sufficient data for their importance to be
reflected in the quantitative mapping
effort; and (2) providing additional
context within which to examine
potential interactions between cetaceans
and human activities. A ‘‘Feeding Area’’
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BIA for humpback whales in the Gulf of
Alaska region encompasses the waters
east of Kodiak Island (the Albatross and
Portlock Banks), a target for historical
commercial whalers based out of Port
Hobron, Alaska (Ferguson et al. 2015;
Reeves et al. 1985; Witteveen et al.
2007). This BIA also includes waters
along the southeastern side of Shelikof
Strait and in the bays along the
northwestern shore of Kodiak Island.
The highest densities of humpback
whales around the Kodiak Island BIA
occur from July-August (Ferguson et al.
2015).
Minke Whale
Minke whales are most abundant in
the Gulf of Alaska during summer and
occupy localized feeding areas (Zerbini
et al. 2006). Concentrations of minke
whales have occurred along the north
coast of Kodiak Island (and along the
south coast of the Alaska Peninsula
(Zerbini et al. 2006). The current
estimate for minke whales between
Kenai Fjords and the Aleutian Islands is
1,233 individuals (Zerbini et al. 2006).
During shipboard surveys conducted in
2003, three minke whale sightings were
made, all near the eastern extent of the
survey from nearshore Prince William
Sound to the shelf break (NMML 2003).
Minke whales become scarce in the
Gulf of Alaska in fall; most whales are
thought to leave the region by October
(Consiglieri et al. 1982). Minke whales
are migratory in Alaska, but recently
have been observed off Cape Starichkof
and Anchor Point year-round (Muto et
al. 2017). During Cook Inlet-wide aerial
surveys conducted from 1993 to 2004,
minke whales were encountered three
times (1998, 1999, and 2006), both times
off Anchor Point 16 miles northwest of
Homer (Shelden et al. 2013, 2015,
2017). A minke whale was also reported
off Cape Starichkof in 2011 (A. Holmes,
pers. comm.) and 2013 (E. Fernandez
and C. Hesselbach, pers. comm.),
suggesting this location is regularly used
by minke whales, including during the
winter. Several minke whales were
recorded off Cape Starichkof in early
summer 2013 during exploratory
drilling (Owl Ridge 2014), suggesting
this location is regularly used by minke
whales year-round. During Apache’s
2014 survey, a total of 2 minke whale
groups (3 individuals) were observed
during this time period, one sighting to
the southeast of Kalgin Island and
another sighting near Homer (LomacMacNair et al. 2014). SAExploration
noted one minke whale near Tuxedni
Bay in 2015 (Kendall et al. 2015). This
species is unlikely to be seen in upper
Cook Inlet but may be encountered in
the mid and lower Inlet.
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Killer Whales
Two different stocks of killer whales
inhabit the Cook Inlet region of Alaska:
the Alaska Resident Stock and the Gulf
of Alaska, Aleutian Islands, Bering Sea
Transient Stock (Muto et al 2017).
Seasonal and year-round occurrence has
been noted for killer whales throughout
Alaska (Braham and Dahlheim 1982),
where whales have been labeled as
‘‘resident,’’ ‘‘transient,’’ and ‘‘offshore’’
type killer whales (Dahlheim et al. 2008;
Ford et al. 2000). The killer whales
using Cook Inlet are thought to be a mix
of resident and transient individuals
from two different stocks: the Alaska
Resident Stock, and the Gulf of Alaska,
Aleutian Islands, and Bering Sea
Transient Stock (Allen and Angliss
2015). Although recent studies have
documented movements of Alaska
Resident killer whales from the Bering
Sea into the Gulf of Alaska as far north
as southern Kodiak Island, none of these
whales have been photographed further
north and east in the Gulf of Alaska
where regular photo-identification
studies have been conducted since 1984
(Muto et al. 2017).
Killer whales are occasionally
observed in lower Cook Inlet, especially
near Homer and Port Graham (Shelden
et al. 2003; Rugh et al. 2005). The few
whales that have been photographically
identified in lower Cook Inlet belong to
resident groups more commonly found
in nearby Kenai Fjords and Prince
William Sound (Shelden et al. 2003).
The availability of these prey species
largely determines the likeliest times for
killer whales to be in the area. During
aerial surveys conducted between 1993
and 2004, killer whales were observed
on only three flights, all in the
Kachemak and English Bay area (Rugh
et al. 2005). However, anecdotal reports
of killer whales feeding on belugas in
upper Cook Inlet began increasing in the
1990s, possibly in response to declines
in sea lion and harbor seal prey
elsewhere (Shelden et al. 2003).
One killer whale group of two
individuals was observed during the
2015 SAExploration seismic program
near the North Foreland (Kendall et al.
2015). During NMFS aerial surveys,
killer whales were observed in 1994
(Kamishak Bay), 1997 (Kachemak Bay),
2001 (Port Graham), 2005 (Iniskin Bay),
2010 (Elizabeth and Augustine Islands),
and 2012 (Kachemak Bay; Shelden et al.
2013). Eleven killer whale strandings
have been reported in Turnagain Arm,
six in May 1991, and five in August
1993. This species is expected to be
rarely seen in upper Cook Inlet but may
be encountered in the mid and lower
Inlet.
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12339
Gray Whales
Gray whales have been reported
feeding near Kodiak Island, in
southeastern Alaska, and south along
the Pacific Northwest (Allen and
Angliss 2013). Because most gray
whales migrating through the Gulf of
Alaska region are thought to take a
coastal route, BIA boundaries for the
migratory corridor in this region were
defined by the extent of the continental
shelf (Ferguson et al. 2015).
Most gray whales calve and breed
from late December to early February in
protected waters along the western coast
of Baja California, Mexico. In spring, the
ENP stock of gray whales migrates
approximately 8,000 km (5,000 mi) to
feeding grounds in the Bering and
Chukchi seas before returning to their
wintering areas in the fall (Rice and
Wolman 1971). Northward migration,
primarily of individuals without calves,
begins in February; some cow/calf pairs
delay their departure from the calving
area until well into April (Jones and
Swartz 1984).
Gray whales approach the proposed
action area in late March, April, May,
and June, and leave again in November
and December (Consiglieri et al. 1982;
Rice and Wolman 1971) but migrate past
the mouth of Cook Inlet to and from
northern feeding grounds. Some gray
whales do not migrate completely from
Baja to the Chukchi Sea but instead feed
in select coastal areas in the Pacific
Northwest, including lower Cook Inlet
(Moore et al. 2007). Most of the
population follows the outer coast of the
Kodiak Archipelago from the Kenai
Peninsula in spring or the Alaska
Peninsula in fall (Consiglieri et al. 1982;
Rice and Wolman 1971). Though most
gray whales migrate past Cook Inlet,
small numbers have been noted by
fishers near Kachemak Bay, and north of
Anchor Point (BOEM 2015). During the
NMFS aerial surveys, gray whales were
observed in the month of June in 1994,
2000, 2001, 2005 and 2009 on the east
side of Cook Inlet near Port Graham and
Elizabeth Island but also on the west
side near Kamishak Bay (Shelden et al.
2013). One gray whale was sighted as far
north at the Beluga River. Additionally,
summering gray whales were seen
offshore of Cape Starichkof by marine
mammal observers monitoring
Buccaneer’s Cosmopolitan drilling
program in 2013 (Owl Ridge 2014).
During Apache’s 2012 seismic program,
nine gray whales were observed in June
and July (Lomac-MacNair et al. 2013).
During Apache’s seismic program in
2014, one gray whale was observed
(Lomac- MacNair et al. 2014). During
SAExploration’s seismic survey in 2015,
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no gray whales were observed (Kendall
et al. 2015). This species is unlikely to
be seen in upper Cook Inlet but may be
encountered in the mid and lower Inlet.
Cook Inlet Beluga Whales
The Cook Inlet beluga whale DPS is
a small geographically isolated
population that is separated from other
beluga populations by the Alaska
Peninsula. The population is genetically
distinct from other Alaska populations
suggesting the peninsula is an effective
barrier to genetic exchange (O’CorryCrowe et al. 1997). The Cook Inlet
beluga whale population is estimated to
have declined from 1,300 animals in the
1970s (Calkins 1989) to about 340
animals in 2014 (Shelden et al. 2015).
The precipitous decline documented in
the mid-1990s was attributed to
unsustainable subsistence practices by
Alaska Native hunters (harvest of >50
whales per year) (Mahoney and Shelden
2000). In 2006, a moratorium to cease
hunting was agreed upon to protect the
species. In April 2011, NMFS
designated critical habitat for the beluga
under the ESA (76 FR 20180) as shown
on Figure 13 of the application. NMFS
finalized the Conservation Plan for the
Cook Inlet beluga in 2008 (NMFS
2008a). NMFS finalized the Recovery
Plan for Cook Inlet beluga whales in
2016 (NMFS 2016a).
The Cook Inlet beluga stock remains
within Cook Inlet throughout the year
(Goetz et al. 2012a). Two areas,
consisting of 7,809 km2 (3,016 mi2) of
marine and estuarine environments
considered essential for the species’
survival and recovery were designated
critical habitat. However, in recent years
the range of the beluga whale has
contracted to the upper reaches of Cook
Inlet because of the decline in the
population (Rugh et al. 2010). Area 1 of
the Cook Inlet beluga whale critical
habitat encompasses all marine waters
of Cook Inlet north of a line connecting
Point Possession (61.04° N, 150.37° W)
and the mouth of Three Mile Creek
(61.08.55° N, 151.04.40° W), including
waters of the Susitna, Little Susitna, and
Chickaloon Rivers below mean higher
high water (MHHW). This area provides
important habitat during ice-free
months and is used intensively by Cook
Inlet beluga between April and
November (NMFS 2016a).
Since 1993, NMFS has conducted
annual aerial surveys in June, July or
August to document the distribution
and abundance of beluga whales in
Cook Inlet. The collective survey results
show that beluga whales have been
consistently found near or in river
mouths along the northern shores of
upper Cook Inlet (i.e., north of East and
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West Foreland). In particular, beluga
whale groups are seen in the Susitna
River Delta, Knik Arm, and along the
shores of Chickaloon Bay. Small groups
had also been recorded seen farther
south in Kachemak Bay, Redoubt Bay
(Big River), and Trading Bay (McArthur
River) prior to 1996 but very rarely
thereafter. Since the mid-1990s, most
(96 to 100 percent) beluga whales in
upper Cook Inlet have been
concentrated in shallow areas near river
mouths, no longer occurring in the
central or southern portions of Cook
Inlet (Hobbs et al. 2008). Based on these
aerial surveys, the concentration of
beluga whales in the northernmost
portion of Cook Inlet appears to be
consistent from June to October (Rugh et
al. 2000, 2004a, 2005, 2006, 2007).
Though Cook Inlet beluga whales can
be found throughout the inlet at any
time of year, they spend the ice-free
months generally in the upper Cook
Inlet, shifting into the middle and lower
Inlet in winter (Hobbs et al. 2005). In
1999, one beluga whale was tagged with
a satellite transmitter, and its
movements were recorded from June
through September of that year. Since
1999, 18 beluga whales in upper Cook
Inlet have been captured and fitted with
satellite tags to provide information on
their movements during late summer,
fall, winter, and spring. Using location
data from satellite-tagged Cook Inlet
belugas, Ezer et al. (2013) found most
tagged whales were in the lower to
middle inlet (70 to 100 percent of tagged
whales) during January through March,
near the Susitna River Delta from April
to July (60 to 90 percent of tagged
whales) and in the Knik and Turnagain
Arms from August to December.
During the spring and summer, beluga
whales are generally concentrated near
the warmer waters of river mouths
where prey availability is high and
predator occurrence is low (Moore et al.
2000). Beluga whales in Cook Inlet are
believed to mostly calve between midMay and mid-July, and concurrently
breed between late spring and early
summer (NMFS 2016a), primarily in
upper Cook Inlet. Movement was
correlated with the peak discharge of
seven major rivers emptying into Cook
Inlet. Boat-based surveys from 2005 to
the present (McGuire and Stephens
2017), and initial results from passive
acoustic monitoring across the entire
inlet (Castellote et al. 2016) also support
seasonal patterns observed with other
methods. Other surveys also confirm
Cook Inlet belugas near the Kenai River
during summer months (McGuire and
Stephens 2017).
During the summer and fall, beluga
whales are concentrated near the
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Susitna River mouth, Knik Arm,
Turnagain Arm, and Chickaloon Bay
(Nemeth et al. 2007) where they feed on
migrating eulachon (Thaleichthys
pacificus) and salmon (Onchorhyncus
spp.) (Moore et al. 2000). Data from
tagged whales (14 tags between July and
March 2000 through 2003) show beluga
whales use upper Cook Inlet intensively
between summer and late autumn
(Hobbs et al. 2005). Critical Habitat Area
1 reflects this summer distribution.
As late as October, beluga whales
tagged with satellite transmitters
continued to use Knik Arm and
Turnagain Arm and Chickaloon Bay, but
some ranged into lower Cook Inlet south
to Chinitna Bay, Tuxedni Bay, and
Trading Bay (McArthur River) in the fall
(Hobbs et al. 2005). Data from NMFS
aerial surveys, opportunistic sighting
reports, and satellite-tagged beluga
whales confirm they are more widely
dispersed throughout Cook Inlet during
the winter months (November–April),
with animals found between Kalgin
Island and Point Possession. In
November, beluga whales moved
between Knik Arm, Turnagain Arm, and
Chickaloon Bay, similar to patterns
observed in September (Hobbs et al.
2005). By December, beluga whales
were distributed throughout the upper
to mid-inlet. From January into March,
they moved as far south as Kalgin Island
and slightly beyond in central offshore
waters. Beluga whales also made
occasional excursions into Knik Arm
and Turnagain Arm in February and
March despite ice cover greater than 90
percent (Hobbs et al. 2005).
During Apache’s seismic test program
in 2011 along the west coast of Redoubt
Bay, lower Cook Inlet, a total of 33
beluga whales were sighted during the
survey (Lomac-MacNair et al. 2013).
During Apache’s 2012 seismic program
in mid-inlet, a total of 151 sightings of
approximately 1,463 estimated
individual beluga whales were observed
(Lomac-MacNair et al. 2013). During
SAExploration’s 2015 seismic program,
a total of eight sightings of
approximately 33 estimated individual
beluga whales were visually observed
during this time period and there were
two acoustic detections of beluga
whales (Kendall et al. 2015). Hilcorp
recently reported 143 sightings of beluga
whales while conducting pipeline work
near Ladd Landing in upper Cook Inlet,
which is not near the area that seismic
surveys are proposed but near some
potential well sites.
Ferguson et al. (2015) delineated one
‘‘Small’’ and ‘‘Resident’’ BIA for Cook
Inlet beluga whales. Small and Resident
BIAs are defined as ‘‘areas and time
within which small and resident
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populations occupy a limited
geographic extent’’ (Ferguson et al.
2015). The Cook Inlet beluga whale BIA
was delineated using the habitat model
results of Goetz et al. 2012 and the
critical habitat boundaries (76 FR
20180).
Harbor Porpoise
In Alaskan waters, three stocks of
harbor porpoises are currently
recognized for management purposes:
Southeast Alaska, Gulf of Alaska, and
Bering Sea Stocks (Muto et al. 2017).
Porpoises found in Cook Inlet belong to
the Gulf of Alaska Stock which is
distributed from Cape Suckling to
Unimak Pass and most recently was
estimated to number 31,046 individuals
(Muto et al. 2017). They are one of the
three marine mammals (the other two
being belugas and harbor seals)
regularly seen throughout Cook Inlet
(Nemeth et al. 2007), especially during
spring eulachon and summer salmon
runs.
Harbor porpoises primarily frequent
the coastal waters of the Gulf of Alaska
and Southeast Alaska (Dahlheim et al.
2000, 2008), typically occurring in
waters less than 100 m deep (Hobbs and
Waite 2010). The range of the Gulf of
Alaska stock includes the entire Cook
Inlet, Shelikof Strait, and the Gulf of
Alaska. Harbor porpoises have been
reported in lower Cook Inlet from Cape
Douglas to the West Foreland,
Kachemak Bay, and offshore (Rugh et al.
2005a). Although they have been
frequently observed during aerial
surveys in Cook Inlet (Shelden et al.
2014), most sightings are of single
animals, and are concentrated at
Chinitna and Tuxedni bays on the west
side of lower Cook Inlet (Rugh et al.
2005) and in the upper inlet. The
occurrence of larger numbers of
porpoise in the lower Cook Inlet may be
driven by greater availability of
preferred prey and possibly less
competition with beluga whales, as
belugas move into upper inlet waters to
forage on Pacific salmon during the
summer months (Shelden et al. 2014).
The harbor porpoise frequently has
been observed during summer aerial
surveys of Cook Inlet, with most
sightings of individuals concentrated at
Chinitna and Tuxedni Bays on the west
side of lower Cook Inlet (Figure 14 of
the application; Rugh et al. 2005).
Mating probably occurs from June or
July to October, with peak calving in
May and June (as cited in Consiglieri et
al. 1982). Small numbers of harbor
porpoises have been consistently
reported in the upper Cook Inlet
between April and October, except for a
recent survey that recorded higher
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numbers than typical. NMFS aerial
surveys have identified many harbor
porpoise sightings throughout Cook
Inlet.
During Apache’s 2012 seismic
program, 137 sightings (190 individuals)
were observed between May and August
(Lomac-MacNair et al. 2013). LomacMacNair et al. 2014 identified 77 groups
of harbor porpoise totaling 13
individuals during Apache’s 2014
seismic survey, both from vessels and
aircraft, during the month of May.
During SAExploration’s 2015 seismic
survey, 52 sightings (65 individuals)
were observed north of the Forelands
(Kendall et al. 2015).
Recent passive acoustic research in
Cook Inlet by Alaska Department of Fish
and Game (ADF&G) and the Marine
Mammal Laboratory (MML) have
indicated that harbor porpoises occur
more frequently than expected,
particularly in the West Foreland area in
the spring (Castellote et al. 2016),
although overall numbers are still
unknown at this time.
Dall’s Porpoise
Dall’s porpoises are widely
distributed throughout the North Pacific
Ocean including preferring deep
offshore and shelf-slopes, and deep
oceanic waters (Muto et al. 2017). The
Dall’s porpoise range in Alaska extends
into the southern portion of the Petition
region (Figure 14 of the application).
Dall’s porpoises are present year-round
throughout their entire range in the
northeast including the Gulf of Alaska,
and occasionally the Cook Inlet area
(Morejohn 1979). This porpoise also has
been observed in lower Cook Inlet,
around Kachemak Bay, and rarely near
Anchor Point (Owl Ridge 2014; BOEM
2015).
Throughout most of the eastern North
Pacific they are present during all
months of the year, although there may
be seasonal onshore-offshore
movements along the west coast of the
continental United States and winter
movements of populations out of areas
with ice such as Prince William Sound
(Muto et al. 2017). Dall’s porpoises were
observed (2 groups, 3 individuals)
during Apache’s 2014 seismic survey
which occurred in the summer months
(Lomac-MacNair et al. 2014). Dall’s
porpoises were observed during the
month of June in 1997 (Iniskin Bay), 199
(Barren Island), and 2000 (Elizabeth
Island, Kamishak Bay and Barren
Island) (Shelden et al. 2013). Dall’s
porpoises have been observed in lower
Cook Inlet, including Kachemak Bay
and near Anchor Point (Owl Ridge
2014). One Dall’s porpoise was observed
in August north of Nikiski in the middle
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12341
of the Inlet during SAExploration’s 2015
seismic program (Kendall et al. 2015).
Harbor Seal
Harbor seals occupy a wide variety of
habitats in freshwater and saltwater in
protected and exposed coastlines and
range from Baja California north along
the west coasts of Washington, Oregon,
and California, British Columbia, and
Southeast Alaska; west through the Gulf
of Alaska, Prince William Sound, and
the Aleutian Islands; and north in the
Bering Sea to Cape Newenham and the
Pribilof Islands. Harbor seals are found
throughout the entire lower Cook Inlet
coastline, hauling out on beaches,
islands, mudflats, and at the mouths of
rivers where they whelp and feed (Muto
et al. 2017).
The major haul out sites for harbor
seals are located in lower Cook Inlet.
The presence of harbor seals in upper
Cook Inlet is seasonal. In Cook Inlet,
seal use of western habitats is greater
than use of the eastern coastline
(Boveng et al. 2012). NMFS has
documented a strong seasonal pattern of
more coastal and restricted spatial use
during the spring and summer for
breeding, pupping, and molting, and
more wide- ranging seal movements
within and outside of Cook Inlet during
the winter months (Boveng et al. 2012).
Large-scale patterns indicate a portion
of harbor seals captured in Cook Inlet
move out of the area in the fall, and into
habitats within Shelikof Strait, Northern
Kodiak Island, and coastal habitats of
the Alaska Peninsula, and are most
concentrated in Kachemak Bay, across
Cook Inlet toward Iniskin and Iliamna
Bays, and south through the Kamishak
Bay, Cape Douglas and Shelikof Strait
regions (Boveng et al. 2012).
A portion of the Cook Inlet seals move
into the Gulf of Alaska and Shelikof
Strait during the winter months
(London et al. 2012). Seals move back
into Cook Inlet as the breeding season
approaches and their spatial use is more
concentrated around haul-out areas
(Boveng et al. 2012; London et al. 2012).
Some seals expand their use of the
northern portion of Cook Inlet.
However, in general, seals that were
captured and tracked in the southern
portion of Cook Inlet remained south of
the Forelands (Boveng et al. 2012).
Important harbor seal haul-out areas
occur within Kamishak and Kachemak
Bays and along the coast of the Kodiak
Archipelago and the Alaska Peninsula.
Chinitna Bay, Clearwater and Chinitna
Creeks, Tuxedni Bay, Kamishak Bay, Oil
Bay, Pomeroy and Iniskin Islands, and
Augustine Island are also important
spring- summer breeding and molting
areas and known haul-outs sites (Figure
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15 of the application). Small-scale
patterns of movement within Cook Inlet
also occur (Boveng et al. 2012).
Montgomery et al. (2007) recorded over
200 haul out sites in lower Cook Inlet
alone. However, only a few dozen to a
couple hundred seals seasonally occur
in upper Cook Inlet (Rugh et al. 2005),
mostly at the mouth of the Susitna River
where their numbers vary in concert
with the spring eulachon and summer
salmon runs (Nemeth et al. 2007;
Boveng et al. 2012).
The Cook Inlet/Shelikof Stock is
distributed from Anchorage into lower
Cook Inlet during summer and from
lower Cook Inlet through Shelikof Strait
to Unimak Pass during winter (Boveng
et al. 2012). Large numbers concentrate
at the river mouths and embayments of
lower Cook Inlet, including the Fox
River mouth in Kachemak Bay, and
several haul outs have been identified
on the southern end of Kalgin Island in
lower Cook Inlet (Rugh et al. 2005;
Boveng et al. 2012). Montgomery et al.
(2007) recorded over 200 haul-out sites
in lower Cook Inlet alone. During
Apache’s 2012 seismic program, harbor
seals were observed in the project area
from early May until the end of the
seismic operations in late September
(Lomac-MacNair et al. 2013). Also in
2012, up to 100 harbor seals were
observed hauled out at the mouths of
the Theodore and Lewis rivers during
monitoring activity associated with
Apache’s 2012 Cook Inlet seismic
program. During Apache’s 2014 seismic
program, 492 groups of harbor seals (613
individuals) were observed. This was
the highest sighting rate of any marine
mammal observed during the summer of
2014 (Lomac-MacNair et al. 2014).
During SAExploration’s 2015 seismic
survey, 823 sightings (1,680 individuals)
were observed north and between the
Forelands (Kendall et al. 2015).
Steller Sea Lions
The western DPS (WDPS) stock of
Steller sea lions most likely occurs in
Cook Inlet (78 FR 66139). The center of
abundance for the Western DPS is
considered to extend from Kenai to
Kiska Island (NMFS 2008b). The WDPS
of the Steller sea lion is defined as all
populations west of longitude 144° W to
the western end of the Aleutian Islands.
The range of the WDPS includes 38
rookeries and hundreds of haul out
sites. The Hilcorp action area only
considers the WDPS stock. The most
recent comprehensive aerial
photographic and land-based surveys of
WDPS Steller sea lions in Alaska were
conducted during the 2014 and 2015
breeding seasons (Fritz et al. 2015).
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The WDPS of Steller sea lions is
currently listed as endangered under the
ESA (55 FR 49204) and designated as
depleted under the MMPA. Critical
habitat was designated on August 27,
1993 (58 FR 45269) south of the
proposed project area in the Cook Inlet
region (Figure 16 of the application).
The critical habitat designation for the
WDPS of Steller sea lions was
determined to include a 37 km (20 nm)
buffer around all major haul outs and
rookeries, and associated terrestrial,
atmospheric, and aquatic zones, plus
three large offshore foraging areas
(Figure 16 of the application). NMFS
also designated no entry zones around
rookeries (50 CFR 223.202). Designated
critical habitat is located outside Cook
Inlet at Gore Point, Elizabeth Island,
Perl Island, and Chugach Island (NMFS
2008b).
The geographic center of Steller sea
lion distribution is the Aleutian Islands
and the Gulf of Alaska, although as the
WDPS has declined, rookeries in the
west became progressively smaller
(NMFS 2008b). Steller sea lion habitat
includes terrestrial sites for breeding
and pupping (rookeries), resting (haul
outs), and marine foraging areas. Nearly
all rookeries are at sites inaccessible to
terrestrial predators on remote rocks,
islands, and reefs. Steller sea lions
inhabit lower Cook Inlet, especially near
Shaw Island and Elizabeth Island
(Nagahut Rocks) haul out sites (Rugh et
al. 2005) but are rarely seen in upper
Cook Inlet (Nemeth et al. 2007). Steller
sea lions occur in Cook Inlet but south
of Anchor Point around the offshore
islands and along the west coast of the
upper inlet in the bays (Chinitna Bay,
Iniskin Bay, etc.) (Rugh et al. 2005).
Portions of the southern reaches of the
lower inlet are designated as critical
habitat, including a 20-nm buffer
around all major haulout sites and
rookeries. Rookeries and haul out sites
in lower Cook Inlet include those near
the mouth of the inlet, which are far
south of the project area.
Steller sea lions feed largely on
walleye pollock, salmon, and
arrowtooth flounder during the summer,
and walleye pollock and Pacific cod
during the winter (Sinclair and
Zeppelin 2002). Except for salmon, none
of these are found in abundance in
upper Cook Inlet (Nemeth et al. 2007).
Steller sea lions can travel
considerable distances (Baba et al.
2000). Steller sea lions are not known to
migrate annually, but individuals may
widely disperse outside of the breeding
season (late May to early July; Jemison
et al. 2013; Allen and Angliss 2014).
Most adult Steller sea lions inhabit
rookeries during the breeding season
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(late May to early July). Some juveniles
and non-breeding adults occur at or near
rookeries during the breeding season,
but most are on haul outs. Adult males
may disperse widely after the breeding
season and, during fall and winter,
many sea lions increase use of haul
outs, especially terrestrial sites but also
on sea ice in the Bering Sea (NMFS
2008b).
Steller sea lions have been observed
during marine mammal surveys
conducted in Cook Inlet. In 2012, during
Apache’s 3D Seismic surveys, there
were three sightings of approximately
four individuals in upper Cook Inlet
(Lomac-MacNair et al. 2013). Marine
mammal observers associated with
Buccaneer’s drilling project off Cape
Starichkof observed seven Steller sea
lions during the summer of 2013 (Owl
Ridge 2014). During SAExploration’s 3D
Seismic Program in 2015, four Steller
sea lions were observed in Cook Inlet.
One sighting occurred between the West
and East Forelands, one near Nikiski
and one northeast of the North Foreland
in the center of Cook Inlet (Kendall et
al. 2015). During NMFS Cook Inlet
beluga whale aerial surveys from 2000–
2016, there were 39 sightings of 769
estimated individual Steller sea lions in
lower Cook Inlet (Shelden et al. 2017).
Sightings of large congregations of
Steller sea lions during NMFS aerial
surveys occurred outside the Petition
region, on land in the mouth of Cook
Inlet (e.g., Elizabeth and Shaw Islands).
California Sea Lions
There is limited information on the
presence of California sea lions in
Alaska. From 1973 to 2003, a total of 52
California sea lions were reported in
Alaska, with sightings increasing in the
later years. Most sightings occurred in
the spring; however, they have been
observed during all seasons. California
sea lion presence in Alaska was
correlated with increasing population
numbers within their southern breeding
range (Maniscalco et al. 2004).
There have been relatively few
California sea lions observed in Alaska,
most are often alone or occasionally in
small groups of two or more and usually
associated with Steller sea lions at their
haulouts and rookeries (Maniscalco et
al. 2004). California sea lions are not
typically observed farther north than
southeast Alaska, and sightings are very
rare in Cook Inlet. California sea lions
have not been observed during the
annual NMFS aerial surveys in Cook
Inlet. However, a sighting of two
California sea lions was documented
during the Apache 2012 seismic survey
(Lomac-MacNair et al. 2013).
Additionally, NMFS’ anecdotal sighting
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database has four sightings in Seward
and Kachemak Bay.
The California sea lion breeds from
the southern Baja Peninsula north to
An˜o Nuevo Island, California. Breeding
season lasts from May to August, and
most pups are born from May through
July. Their nonbreeding range extends
northward into British Columbia and
occasionally farther north into Alaskan
waters. California sea lions have been
observed in Alaska during all four
seasons; however, most of the sightings
have occurred during the spring
(Maniscalco et al. 2004).
Sections 3 and 4 of the application
summarize available information
regarding status and trends, distribution
and habitat preferences, and behavior
and life history, of the potentially
affected species. Additional information
regarding population trends and threats
may be found in NMFS’s Stock
Assessment Reports (SAR; https://
www.fisheries.noaa.gov/national/
marine-mammal-protection/marine-
mammal-stock-assessment-reportsregion), and more general information
about these species (e.g., physical and
behavioral descriptions) may be found
on NMFS’ website (https://
www.fisheries.noaa.gov/speciesdirectory/).
Table 2 lists all species with expected
potential for occurrence in Cook Inlet
and summarizes information related to
the population or stock, including
regulatory status under the MMPA and
ESA and potential biological removal
(PBR), where known. For taxonomy, we
follow Committee on Taxonomy (2016).
PBR is defined by the MMPA as the
maximum number of animals, not
including natural mortalities, that may
be removed from a marine mammal
stock while allowing that stock to reach
or maintain its optimum sustainable
population (as described in NMFS’
SARs). While no mortality is anticipated
or authorized here, PBR and annual
serious injury and mortality from
anthropogenic sources are included here
as gross indicators of the status of the
species and other threats.
Marine mammal abundance estimates
presented in this document represent
the total number of individuals that
make up a given stock or the total
number estimated within a particular
study or survey area. NMFS’ stock
abundance estimates for most species
represent the total estimate of
individuals within the geographic area,
if known, that comprises that stock. For
some species, this geographic area may
extend beyond U.S. waters. All managed
stocks in this region are assessed in
NMFS’ 2017 U.S. Alaska and Pacific
SARs (Muto et al, 2017; Carretta et al,
2017). All values presented in Table 2
are the most recent available at the time
of publication and are available in the
2017 SARs and draft 2018 SARs
(available online at: https://
www.fisheries.noaa.gov/action/2018draft-marine-mammal-stockassessment-reports-available).
TABLE 2—SPECIES WITH THE POTENTIAL TO OCCUR IN COOK INLET, ALASKA
Common name
Scientific name
ESA/
MMPA
status;
Strategic
(Y/N)1
Stock
Stock abundance
(CV, Nmin, most recent
abundance survey) 2
PBR
Annual
M/SI 3
Order Cetartiodactyla—Cetacea—Superfamily Mysticeti (baleen whales)
Family Eschrichtiidae:
Gray whale .......................
Family Balaenopteridae
(rorquals):
Fin whale ..........................
Minke whale .....................
Humpback whale ..............
Eschrichtius robustus .............
Eastern Pacific .......................
-/-; N
20,990 (0.05, 20,125, 2011) ..
624
4.25
Balaenoptera physalus ...........
Balaenoptera acutorostrata ....
Megaptera novaeangliae ........
Northeastern Pacific ...............
Alaska .....................................
Western North Pacific ............
E/D; Y
-/-; N
E/D; Y
3,168 (0.26,2,554 2013) .........
N/A .........................................
1,107 (0.3, 865, 2006) ...........
5.1
N/A
3
0.4
0
3.2
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family Delphinidae:
Beluga whale ...................
Killer whale .......................
Delphinapterus leucas ............
Orcinus orca ...........................
Cook Inlet ...............................
Alaska Resident .....................
Alaska Transient ....................
E/D; Y
-/-; N
-/-; N
312 (0.1, 287, 2014) ..............
2,347 (N/A, 2,347, 2012) .......
587 (N/A, 587, 2012) .............
0.54
24
5.9
0.57
1
1
Family Phocoenidae (porpoises):
Harbor porpoise ...............
Dall’s porpoise ..................
Phocoena phocoena ..............
Phocoenoides dalli .................
Gulf of Alaska .........................
Alaska .....................................
-/-; Y
-/-; N
31,046 (0.214, N/A, 1998) .....
83,400 (0.097, N/A, 1993) .....
Undet
Undet
72
38
Order Carnivora—Superfamily Pinnipedia
Family Otariidae (eared seals
and sea lions):
Steller sea lion .................
California sea lion ............
Family Phocidae (earless
seals):
Harbor seal .......................
Eumetopias jubatus ................
Zalophus californianus ...........
Western ..................................
U.S. ........................................
E/D; Y
-/-; N
53,303 (N/A, 53,303, 2016) ...
296,750 (153,337, N/A, 2011)
320
9,200
241
331
Phoca vitulina .........................
Cook Inlet/Shelikof .................
-/-; N
27,386 (25,651, N/A, 2011) ...
770
234
1 Endangered
Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the
ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically
designated under the MMPA as depleted and as a strategic stock.
2 NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of stock
abundance. In some cases, CV is not applicable [explain if this is the case]
3 These values, found in NMFS’ SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries,
ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated with estimated mortality due to commercial fisheries is presented in some cases.
Note: Italicized species are not expected to be taken or proposed for authorization.
All species that could potentially
occur in the proposed survey areas are
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included in Table 2. As described
below, all 11 species (with 12 managed
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stocks) temporally and spatially cooccur with the activity to the degree that
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take is reasonably likely to occur, and
we have proposed authorizing it.
In addition, sea otters may be found
in Cook Inlet. However, sea otters are
managed by the U.S. Fish and Wildlife
Service and are not considered further
in this document.
Marine Mammal Hearing
Hearing is the most important sensory
modality for marine mammals
underwater, and exposure to
anthropogenic sound can have
deleterious effects. To appropriately
assess the potential effects of exposure
to sound, it is necessary to understand
the frequency ranges marine mammals
are able to hear. Current data indicate
that not all marine mammal species
have equal hearing capabilities (e.g.,
Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008).
To reflect this, Southall et al. (2007)
recommended that marine mammals be
divided into functional hearing groups
based on directly measured or estimated
hearing ranges on the basis of available
behavioral response data, audiograms
derived using auditory evoked potential
techniques, anatomical modeling, and
other data. Note that no direct
measurements of hearing ability have
been successfully completed for
mysticetes (i.e., low-frequency
cetaceans). Subsequently, NMFS (2018)
described generalized hearing ranges for
these marine mammal hearing groups.
Generalized hearing ranges were chosen
based on the approximately 65 dB
threshold from the normalized
composite audiograms, with the
exception for lower limits for lowfrequency cetaceans where the lower
bound was deemed to be biologically
implausible and the lower bound from
Southall et al. (2007) retained. The
functional groups and the associated
frequencies are indicated below (note
that these frequency ranges correspond
to the range for the composite group,
with the entire range not necessarily
reflecting the capabilities of every
species within that group):
• Low-frequency cetaceans
(mysticetes): generalized hearing is
estimated to occur between
approximately 7 Hz and 35 kHz;
• Mid-frequency cetaceans (larger
toothed whales, beaked whales, and
most delphinids): generalized hearing is
estimated to occur between
approximately 150 Hz and 160 kHz;
• High-frequency cetaceans
(porpoises, river dolphins, and members
of the genera Kogia and
Cephalorhynchus; including two
members of the genus Lagenorhynchus,
on the basis of recent echolocation data
and genetic data): generalized hearing is
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estimated to occur between
approximately 275 Hz and 160 kHz;
• Pinnipeds in water; Phocidae (true
seals): generalized hearing is estimated
to occur between approximately 50 Hz
to 86 kHz; and
• Pinnipeds in water; Otariidae (eared
seals): generalized hearing is estimated
to occur between 60 Hz and 39 kHz.
The pinniped functional hearing
group was modified from Southall et al.
(2007) on the basis of data indicating
that phocid species have consistently
demonstrated an extended frequency
range of hearing compared to otariids,
especially in the higher frequency range
(Hemila¨ et al., 2006; Kastelein et al.,
2009; Reichmuth and Holt, 2013).
For more detail concerning these
groups and associated frequency ranges,
please see NMFS (2018) for a review of
available information. Eleven marine
mammal species (eight cetacean and
three pinniped (two otariid and one
phocid) species) have the reasonable
potential to co-occur with the proposed
survey activities. Please refer to Table 2.
Of the cetacean species that may be
present, four are classified as lowfrequency cetaceans (i.e., all mysticete
species), two are classified as midfrequency cetaceans (i.e., all delphinid
and ziphiid species and the sperm
whale), and two are classified as highfrequency cetaceans (i.e., harbor
porpoise and Kogia spp.).
Potential Effects of Specified Activities
on Marine Mammals and Their Habitat
This section includes a summary and
discussion of the ways that components
of the specified activity may impact
marine mammals and their habitat. The
Estimated Take by Incidental
Harassment section later in this
document includes a quantitative
analysis of the number of individuals
that are expected to be taken by this
activity. The Negligible Impact Analysis
and Determination section considers the
content of this section, the Estimated
Take by Incidental Harassment section,
and the Proposed Mitigation section, to
draw conclusions regarding the likely
impacts of these activities on the
reproductive success or survivorship of
individuals and how those impacts on
individuals are likely to impact marine
mammal species or stocks.
Description of Active Acoustic Sound
Sources
This section contains a brief technical
background on sound, the
characteristics of certain sound types,
and on metrics used in this proposal in
as much as the information is relevant
to the specified activity and to a
discussion of the potential effects of the
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specified activity on marine mammals
found later in this document.
Sound travels in waves, the basic
components of which are frequency,
wavelength, velocity, and amplitude.
Frequency is the number of pressure
waves that pass by a reference point per
unit of time and is measured in Hz or
cycles per second. Wavelength is the
distance between two peaks or
corresponding points of a sound wave
(length of one cycle). Higher frequency
sounds have shorter wavelengths than
lower frequency sounds, and typically
attenuate (decrease) more rapidly,
except in certain cases in shallower
water. Amplitude is the height of the
sound pressure wave or the ‘‘loudness’’
of a sound and is typically described
using the relative unit of the dB. A
sound pressure level (SPL) in dB is
described as the ratio between a
measured pressure and a reference
pressure (for underwater sound, this is
1 microPascal (mPa)) and is a
logarithmic unit that accounts for large
variations in amplitude; therefore, a
relatively small change in dB
corresponds to large changes in sound
pressure. The source level (SL)
represents the SPL referenced at a
distance of 1 m from the source
(referenced to 1 mPa) while the received
level is the SPL at the listener’s position
(referenced to 1 mPa).
Root mean square (rms) is the
quadratic mean sound pressure over the
duration of an impulse. Root mean
square is calculated by squaring all of
the sound amplitudes, averaging the
squares, and then taking the square root
of the average (Urick, 1983). Root mean
square accounts for both positive and
negative values; squaring the pressures
makes all values positive so that they
may be accounted for in the summation
of pressure levels (Hastings and Popper,
2005). This measurement is often used
in the context of discussing behavioral
effects, in part because behavioral
effects, which often result from auditory
cues, may be better expressed through
averaged units than by peak pressures.
Sound exposure level (SEL;
represented as dB re 1 mPa2-s)
represents the total energy contained
within a pulse and considers both
intensity and duration of exposure. Peak
sound pressure (also referred to as zeroto-peak sound pressure or 0-p) 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. Another common
metric is peak-to-peak sound pressure
(pk-pk), which is the algebraic
difference between the peak positive
and peak negative sound pressures.
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Peak-to-peak pressure is typically
approximately 6 dB higher than peak
pressure (Southall et al., 2007).
When underwater objects vibrate or
activity occurs, sound-pressure waves
are created. These waves alternately
compress and decompress the water as
the sound wave travels. Underwater
sound waves radiate in a manner similar
to ripples on the surface of a pond and
may be either directed in a beam or
beams or may radiate in all directions
(omnidirectional sources), as is the case
for pulses produced by the airgun arrays
considered here. The compressions and
decompressions associated with sound
waves are detected as changes in
pressure by aquatic life and man-made
sound receptors such as hydrophones.
Even in the absence of sound from the
specified activity, the underwater
environment is typically loud due to
ambient sound. Ambient sound is
defined as environmental background
sound levels lacking a single source or
point (Richardson et al., 1995), and the
sound level of a region is defined by the
total acoustical energy being generated
by known and unknown sources. These
sources may include physical (e.g.,
wind and waves, earthquakes, ice,
atmospheric sound), biological (e.g.,
sounds produced by marine mammals,
fish, and invertebrates), and
anthropogenic (e.g., vessels, dredging,
construction) sound. A number of
sources contribute to ambient sound,
including the following (Richardson et
al., 1995):
• Wind and waves: The complex
interactions between wind and water
surface, including processes such as
breaking waves and wave-induced
bubble oscillations and cavitation, are a
main source of naturally occurring
ambient sound for frequencies between
200 Hz and 50 kilohertz (kHz) (Mitson,
1995). In general, ambient sound levels
tend to increase with increasing wind
speed and wave height. Surf sound
becomes important near shore, with
measurements collected at a distance of
8.5 km from shore showing an increase
of 10 dB in the 100 to 700 Hz band
during heavy surf conditions;
• Precipitation: Sound from rain and
hail impacting the water surface can
become an important component of total
sound at frequencies above 500 Hz, and
possibly down to 100 Hz during quiet
times;
• Biological: Marine mammals can
contribute significantly to ambient
sound levels, as can some fish and
snapping shrimp. The frequency band
for biological contributions is from
approximately 12 Hz to over 100 kHz;
and
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• Anthropogenic: Sources of ambient
sound related to human activity include
transportation (surface vessels),
dredging and construction, oil and gas
drilling and production, seismic
surveys, sonar, explosions, and ocean
acoustic studies. Vessel noise typically
dominates the total ambient sound for
frequencies between 20 and 300 Hz. In
general, the frequencies of
anthropogenic sounds are below 1 kHz
and, if higher frequency sound levels
are created, they attenuate rapidly.
Sound from identifiable anthropogenic
sources other than the activity of
interest (e.g., a passing vessel) is
sometimes termed background sound, as
opposed to ambient sound.
The sum of the various natural and
anthropogenic sound sources at any
given location and time—which
comprise ‘‘ambient’’ or ‘‘background’’
sound—depends not only on the source
levels (as determined by current
weather conditions and levels of
biological and human activity) but also
on the ability of sound to propagate
through the environment. In turn, sound
propagation is dependent on the
spatially and temporally varying
properties of the water column and sea
floor and is frequency-dependent. As a
result of the dependence on a large
number of varying factors, ambient
sound levels can be expected to vary
widely over both coarse and fine spatial
and temporal scales. Sound levels at a
given frequency and location can vary
by 10–20 dB from day to day
(Richardson et al., 1995). The result is
that, depending on the source type and
its intensity, sound from a given activity
may be a negligible addition to the local
environment or could form a distinctive
signal that may affect marine mammals.
Details of source types are described in
the following text.
Sounds are often considered to fall
into one of two general types: Pulsed
and non-pulsed (defined in the
following). The distinction between
these two sound types is important
because they have differing potential to
cause physical effects, particularly with
regard to hearing (e.g., Ward, 1997 in
Southall et al., 2007). Please see
Southall et al. (2007) for an in-depth
discussion of these concepts.
Pulsed sound sources (e.g., airguns,
explosions, gunshots, sonic booms,
impact pile driving) produce signals
that are brief (typically considered to be
less than one second), broadband, atonal
transients (ANSI, 1986, 2005; Harris,
1998; NIOSH, 1998; ISO, 2003) and
occur either as isolated events or
repeated in some succession. Pulsed
sounds are all characterized by a
relatively rapid rise from ambient
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pressure to a maximal pressure value
followed by a rapid decay period that
may include a period of diminishing,
oscillating maximal and minimal
pressures and generally have an
increased capacity to induce physical
injury as compared with sounds that
lack these features.
Non-pulsed sounds can be tonal,
narrowband, or broadband, brief or
prolonged, and may be either
continuous or non-continuous (ANSI,
1995; NIOSH, 1998). Some of these nonpulsed sounds can be transient signals
of short duration but without the
essential properties of pulses (e.g., rapid
rise time). Examples of non-pulsed
sounds include those produced by
vessels, aircraft, machinery operations
such as drilling or dredging, vibratory
pile driving, and active sonar systems
(such as those used by the U.S. Navy).
The duration of such sounds, as
received at a distance, can be greatly
extended in a highly reverberant
environment.
Airgun arrays produce pulsed signals
with energy in a frequency range from
about 10–2,000 Hz, with most energy
radiated at frequencies below 200 Hz.
The amplitude of the acoustic wave
emitted from the source is equal in all
directions (i.e., omnidirectional), but
airgun arrays do possess some
directionality due to different phase
delays between guns in different
directions. Airgun arrays are typically
tuned to maximize functionality for data
acquisition purposes, meaning that
sound transmitted in horizontal
directions and at higher frequencies is
minimized to the extent possible.
As described above, two types of subbottom profiler would also be used by
Hilcorp during the geotechnical and
geohazard surveys: A low resolution
unit (1–4 kHz) and a high resolution
unit (2–24 kHz).
Potential Effects of Underwater
Sound—Please refer to the information
given previously (‘‘Description of Active
Acoustic Sound Sources’’) regarding
sound, characteristics of sound types,
and metrics used in this document. Note
that, in the following discussion, we
refer in many cases to a recent review
article concerning studies of noiseinduced hearing loss conducted from
1996–2015 (i.e., Finneran, 2015). For
study-specific citations, please see that
work. Anthropogenic sounds cover a
broad range of frequencies and sound
levels and can have a range of highly
variable impacts on marine life, from
none or minor to potentially severe
responses, depending on received
levels, duration of exposure, behavioral
context, and various other factors. The
potential effects of underwater sound
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from active acoustic sources can
potentially result in one or more of the
following: Temporary or permanent
hearing impairment, non-auditory
physical or physiological effects,
behavioral disturbance, stress, and
masking (Richardson et al., 1995;
Gordon et al., 2004; Nowacek et al.,
2007; Southall et al., 2007; Go¨tz et al.,
2009). The degree of effect is
intrinsically related to the signal
characteristics, received level, distance
from the source, and duration of the
sound exposure. In general, sudden,
high level sounds can cause hearing
loss, as can longer exposures to lower
level sounds. Temporary or permanent
loss of hearing will occur almost
exclusively for noise within an animal’s
hearing range. We first describe specific
manifestations of acoustic effects before
providing discussion specific to the use
of airguns.
Richardson et al. (1995) described
zones of increasing intensity of effect
that might be expected to occur, in
relation to distance from a source and
assuming that the signal is within an
animal’s hearing range. First is the area
within which the acoustic signal would
be audible (potentially perceived) to the
animal but not strong enough to elicit
any overt behavioral or physiological
response. The next zone corresponds
with the area where the signal is audible
to the animal and of sufficient intensity
to elicit behavioral or physiological
responsiveness. Third is a zone within
which, for signals of high intensity, the
received level is sufficient to potentially
cause discomfort or tissue damage to
auditory or other systems. Overlaying
these zones to a certain extent is the
area within which masking (i.e., when a
sound interferes with or masks the
ability of an animal to detect a signal of
interest that is above the absolute
hearing threshold) may occur; the
masking zone may be highly variable in
size.
We describe the more severe effects
certain non-auditory physical or
physiological effects only briefly as we
do not expect that use of airgun arrays,
sub-bottom profilers, drill rig
construction, or sheet pile driving are
reasonably likely to result in such
effects (see below for further
discussion). Potential effects from
impulsive sound sources can range in
severity from effects such as behavioral
disturbance or tactile perception to
physical discomfort, slight injury of the
internal organs and the auditory system,
or mortality (Yelverton et al., 1973).
Non-auditory physiological effects or
injuries that theoretically might occur in
marine mammals exposed to high level
underwater sound or as a secondary
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effect of extreme behavioral reactions
(e.g., change in dive profile as a result
of an avoidance reaction) caused by
exposure to sound include neurological
effects, bubble formation, resonance
effects, and other types of organ or
tissue damage (Cox et al., 2006; Southall
et al., 2007; Zimmer and Tyack, 2007;
Tal et al., 2015). The suite of activities
considered here do not involve the use
of devices such as explosives or midfrequency tactical sonar that are
associated with these types of effects.
1. Threshold Shift—Marine mammals
exposed to high-intensity sound, or to
lower-intensity sound for prolonged
periods, can experience hearing
threshold shift (TS), which is the loss of
hearing sensitivity at certain frequency
ranges (Finneran, 2015). TS can be
permanent (PTS), in which case the loss
of hearing sensitivity is not fully
recoverable, or temporary (TTS), in
which case the animal’s hearing
threshold would recover over time
(Southall et al., 2007). Repeated sound
exposure that leads to TTS could cause
PTS. In severe cases of PTS, there can
be total or partial deafness, while in
most cases the animal has an impaired
ability to hear sounds in specific
frequency ranges (Kryter, 1985).
When PTS occurs, there is physical
damage to the sound receptors in the ear
(i.e., tissue damage), whereas TTS
represents primarily tissue fatigue and
is reversible (Southall et al., 2007). In
addition, other investigators have
suggested that TTS is within the normal
bounds of physiological variability and
tolerance and does not represent
physical injury (e.g., Ward, 1997).
Therefore, NMFS does not consider TTS
to constitute auditory injury.
Relationships between TTS and PTS
thresholds have not been studied in
marine mammals. There is no PTS data
for cetaceans, but such relationships are
assumed to be similar to those in
humans and other terrestrial mammals.
PTS typically occurs at exposure levels
at least several decibels above (a 40-dB
threshold shift approximates PTS onset;
e.g., Kryter et al., 1966; Miller, 1974)
which would induce mild TTS (a 6-dB
threshold shift approximates TTS onset;
e.g., Southall et al. 2007). Based on data
from terrestrial mammals, a
precautionary assumption is that the
PTS thresholds for impulse sounds
(such as airgun pulses as received close
to the source) are at least 6 dB higher
than the TTS threshold on a peakpressure basis, and PTS cumulative
sound exposure level (SELcum)
thresholds are 15 to 20 dB higher than
TTS SELcum thresholds (Southall et al.,
2007). Given the higher level of sound
combined with longer exposure
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duration necessary to cause PTS, it is
expected that limited PTS could occur
from the proposed activities. For midfrequency cetaceans in particular,
potential protective mechanisms may
help limit onset of TTS or prevent onset
of PTS. Such mechanisms include
dampening of hearing, auditory
adaptation, or behavioral amelioration
(e.g., Nachtigall and Supin, 2013; Miller
et al., 2012; Finneran et al., 2015; Popov
et al., 2016). Given the higher level of
sound, longer durations of exposure
necessary to cause PTS, it is possible
but unlikely PTS would occur during
the proposed seismic surveys,
geotechnical surveys, or other
exploratory drilling activities.
TTS is the mildest form of hearing
impairment that can occur during
exposure to sound (Kryter, 1985). While
experiencing TTS, the hearing threshold
rises, and a sound must be at a higher
level in order to be heard. In terrestrial
and marine mammals, TTS can last from
minutes or hours to days (in cases of
strong TTS). In many cases, hearing
sensitivity recovers rapidly after
exposure to the sound ends. Few data
on sound levels and durations necessary
to elicit mild TTS have been obtained
for marine mammals.
Marine mammal hearing plays a
critical role in communication with
conspecifics, and interpretation of
environmental cues for purposes such
as predator avoidance and prey capture.
Depending on the degree (elevation of
threshold in dB), duration (i.e., recovery
time), and frequency range of TTS, and
the context in which it is experienced,
TTS can have effects on marine
mammals ranging from discountable to
serious. For example, a marine mammal
may be able to readily compensate for
a brief, relatively small amount of TTS
in a non-critical frequency range that
occurs during a time where ambient
noise is lower and there are not as many
competing sounds present.
Alternatively, a larger amount and
longer duration of TTS sustained during
time when communication is critical for
successful mother/calf interactions
could have more serious impacts.
Finneran et al. (2015) measured
hearing thresholds in three captive
bottlenose dolphins before and after
exposure to ten pulses produced by a
seismic airgun in order to study TTS
induced after exposure to multiple
pulses. Exposures began at relatively
low levels and gradually increased over
a period of several months, with the
highest exposures at peak SPLs from
196 to 210 dB and cumulative
(unweighted) SELs from 193–195 dB.
No substantial TTS was observed. In
addition, behavioral reactions were
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observed that indicated that animals can
learn behaviors that effectively mitigate
noise exposures (although exposure
patterns must be learned, which is less
likely in wild animals than for the
captive animals considered in this
study). The authors note that the failure
to induce more significant auditory
effects is likely due to the intermittent
nature of exposure, the relatively low
peak pressure produced by the acoustic
source, and the low-frequency energy in
airgun pulses as compared with the
frequency range of best sensitivity for
dolphins and other mid-frequency
cetaceans.
Currently, TTS data only exist for four
species of cetaceans (bottlenose dolphin
(Tursiops truncatus), beluga whale
(Delphinapterus leucas), harbor
porpoise, and Yangtze finless porpoise
(Neophocoena asiaeorientalis)) and five
species of pinnipeds (northern elephant
seal, harbor seal, and California sea lion)
exposed to a limited number of sound
sources (i.e., mostly tones and octaveband noise) in laboratory settings
(Finneran, 2015). TTS was not observed
in trained spotted (Phoca largha) and
ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching
previous predictions of TTS onset
(Reichmuth et al., 2016). In general,
harbor seals and harbor porpoises have
a lower TTS onset than other measured
pinniped or cetacean species (Finneran,
2015). Additionally, the existing marine
mammal TTS data come from a limited
number of individuals within these
species. There are no data available on
noise-induced hearing loss for
mysticetes. For summaries of data on
TTS in marine mammals or for further
discussion of TTS onset thresholds,
please see Southall et al. (2007),
Finneran and Jenkins (2012), Finneran
(2015), and Table 5 in NMFS (2018).
Critical questions remain regarding
the rate of TTS growth and recovery
after exposure to intermittent noise and
the effects of single and multiple pulses.
Data at present are also insufficient to
construct generalized models for
recovery and determine the time
necessary to treat subsequent exposures
as independent events. More
information is needed on the
relationship between auditory evoked
potential and behavioral measures of
TTS for various stimuli. For summaries
of data on TTS in marine mammals or
for further discussion of TTS onset
thresholds, please see Southall et al.
(2007), Finneran and Jenkins (2012),
Finneran (2015), and NMFS (2016).
Marine mammals in the action area
during the proposed activities are less
likely to incur TTS hearing impairment
from some of the sources proposed to be
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used due to the characteristics of the
sound sources, particularly sources such
as the water jets, which include lower
source levels (176 dB @1m) and
generally very short pulses and duration
of the sound. Even for high-frequency
cetacean species (e.g., harbor porpoises),
which may have increased sensitivity to
TTS (Lucke et al., 2009; Kastelein et al.,
2012b), individuals would have to make
a very close approach and also remain
very close to vessels operating these
sources in order to receive multiple
exposures at relatively high levels, as
would be necessary to cause TTS.
Intermittent exposures—as would occur
due to the brief, transient signals
produced by these sources—require a
higher cumulative SEL to induce TTS
than would continuous exposures of the
same duration (i.e., intermittent
exposure results in lower levels of TTS)
(Mooney et al., 2009a; Finneran et al.,
2010). Moreover, most marine mammals
would more likely avoid a loud sound
source rather than swim in such close
proximity as to result in TTS (much less
PTS). Kremser et al. (2005) noted that
the probability of a cetacean swimming
through the area of exposure when a
sub-bottom profiler emits a pulse is
small—because if the animal was in the
area, it would have to pass the
transducer at close range in order to be
subjected to sound levels that could
cause temporary threshold shift and
would likely exhibit avoidance behavior
to the area near the transducer rather
than swim through at such a close
range. Further, the restricted beam
shape of the sub-bottom profiler and
other geophysical survey equipment
makes it unlikely that an animal would
be exposed more than briefly during the
passage of the vessel. Boebel et al.
(2005) concluded similarly for single
and multibeam echosounders, and more
recently, Lurton (2016) conducted a
modeling exercise and concluded
similarly that likely potential for
acoustic injury from these types of
systems is negligible, but that behavioral
response cannot be ruled out. Animals
may avoid the area around the survey
vessels, thereby reducing exposure.
Effects of non-pulsed sound on marine
mammals, such as vibratory pile
driving, are less studied. In a study by
Malme et al. (1986) on gray whales as
well as Richardson et al. (1997) on
beluga whales, the only reactions
documented in response to drilling
sound playbacks were behavioral
reactions. Any disturbance to marine
mammals is likely to be in the form of
temporary avoidance or alteration of
opportunistic foraging behavior near the
survey location.
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2. Behavioral Effects—Behavioral
disturbance may include a variety of
effects, including subtle changes in
behavior (e.g., minor or brief avoidance
of an area or changes in vocalizations),
more conspicuous changes in similar
behavioral activities, and more
sustained and/or potentially severe
reactions, such as displacement from or
abandonment of high-quality habitat.
Behavioral responses to sound are
highly variable and context-specific and
any reactions depend on numerous
intrinsic and extrinsic factors (e.g.,
species, state of maturity, experience,
current activity, reproductive state,
auditory sensitivity, time of day), as
well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et
al., 2003; Southall et al., 2007; Weilgart,
2007; Archer et al., 2010). Behavioral
reactions can vary not only among
individuals but also within an
individual, depending on previous
experience with a sound source,
context, and numerous other factors
(Ellison et al., 2012), and can vary
depending on characteristics associated
with the sound source (e.g., whether it
is moving or stationary, number of
sources, distance from the source).
Please see Appendices B–C of Southall
et al. (2007) for a review of studies
involving marine mammal behavioral
responses to sound.
Habituation can occur when an
animal’s response to a stimulus wanes
with repeated exposure, usually in the
absence of unpleasant associated events
(Wartzok et al., 2003). Animals are most
likely to habituate to sounds that are
predictable and unvarying. It is
important to note that habituation is
appropriately considered as a
‘‘progressive reduction in response to
stimuli that are perceived as neither
aversive nor beneficial,’’ rather than as,
more generally, moderation in response
to human disturbance (Bejder et al.,
2009). The opposite process is
sensitization, when an unpleasant
experience leads to subsequent
responses, often in the form of
avoidance, at a lower level of exposure.
As noted, behavioral state may affect the
type of response. For example, animals
that are resting may show greater
behavioral change in response to
disturbing sound levels than animals
that are highly motivated to remain in
an area for feeding (Richardson et al.,
1995; NRC, 2003; Wartzok et al., 2003).
Controlled experiments with captive
marine mammals have showed
pronounced behavioral reactions,
including avoidance of loud sound
sources (Ridgway et al., 1997). Observed
responses of wild marine mammals to
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loud pulsed sound sources (typically
seismic airguns or acoustic harassment
devices) have been varied but often
consist of avoidance behavior or other
behavioral changes suggesting
discomfort (Morton and Symonds, 2002;
see also Richardson et al., 1995;
Nowacek et al., 2007). However, many
delphinids approach acoustic source
vessels with no apparent discomfort or
obvious behavioral change (e.g.,
Barkaszi et al., 2012).
Available studies show wide variation
in response to underwater sound;
therefore, it is difficult to predict
specifically how any given sound in a
particular instance might affect marine
mammals perceiving the signal. If a
marine mammal does react briefly to an
underwater sound by changing its
behavior or moving a small distance, the
impacts of the change are unlikely to be
significant to the individual, let alone
the stock or population. However, if a
sound source displaces marine
mammals from an important feeding or
breeding area for a prolonged period,
impacts on individuals and populations
could be significant (e.g., Lusseau and
Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad
categories of potential response, which
we describe in greater detail here, that
include alteration of dive behavior,
alteration of foraging behavior, effects to
breathing, interference with or alteration
of vocalization, avoidance, and flight.
Changes in dive behavior can vary
widely, and may consist of increased or
decreased dive times and surface
intervals as well as changes in the rates
of ascent and descent during a dive (e.g.,
Frankel and Clark 2000; Ng and Leung
2003; Nowacek et al. 2004; Goldbogen et
al. 2013). Variations in dive behavior
may reflect interruptions in biologically
significant activities (e.g., foraging) or
they may be of little biological
significance. The impact of an alteration
to dive behavior resulting from an
acoustic exposure depends on what the
animal is doing at the time of the
exposure and the type and magnitude of
the response.
Disruption of feeding behavior can be
difficult to correlate with anthropogenic
sound exposure, so it is usually inferred
by observed displacement from known
foraging areas, the appearance of
secondary indicators (e.g., bubble nets
or sediment plumes), or changes in dive
behavior. As for other types of
behavioral response, the frequency,
duration, and temporal pattern of signal
presentation, as well as differences in
species sensitivity, are likely
contributing factors to differences in
response in any given circumstance
(e.g., Croll et al. 2001; Nowacek et al.
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2004; Madsen et al. 2006; Yazvenko et
al. 2007). A determination of whether
foraging disruptions incur fitness
consequences would require
information on or estimates of the
energetic requirements of the affected
individuals and the relationship
between prey availability, foraging effort
and success, and the life history stage of
the animal.
Visual tracking, passive acoustic
monitoring, and movement recording
tags were used to quantify sperm whale
behavior prior to, during, and following
exposure to airgun arrays at received
levels in the range 140–160 dB at
distances of 7–13 km, following a phasein of sound intensity and full array
exposures at 1–13 km (Madsen et al.,
2006; Miller et al., 2009). Sperm whales
did not exhibit horizontal avoidance
behavior at the surface. However,
foraging behavior may have been
affected. The sperm whales exhibited 19
percent less vocal (buzz) rate during full
exposure relative to post exposure, and
the whale that was approached most
closely had an extended resting period
and did not resume foraging until the
airguns had ceased firing. The
remaining whales continued to execute
foraging dives throughout exposure;
however, swimming movements during
foraging dives were six percent lower
during exposure than control periods
(Miller et al., 2009). These data raise
concerns that seismic surveys may
impact foraging behavior in sperm
whales, although more data are required
to understand whether the differences
were due to exposure or natural
variation in sperm whale behavior
(Miller et al., 2009).
Variations in respiration naturally
vary with different behaviors and
alterations to breathing rate as a
function of acoustic exposure can be
expected to co-occur with other
behavioral reactions, such as a flight
response or an alteration in diving.
However, respiration rates in and of
themselves may be representative of
annoyance or an acute stress response.
Various studies have shown that
respiration rates may either be
unaffected or could increase, depending
on the species and signal characteristics,
again highlighting the importance in
understanding species differences in the
tolerance of underwater noise when
determining the potential for impacts
resulting from anthropogenic sound
exposure (e.g., Kastelein et al., 2001,
2005, 2006; Gailey et al., 2007).
Marine mammals vocalize for
different purposes and across multiple
modes, such as whistling, echolocation
click production, calling, and singing.
Changes in vocalization behavior in
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response to anthropogenic noise can
occur for any of these modes and may
result from a need to compete with an
increase in background noise or may
reflect increased vigilance or a startle
response. For example, in the presence
of potentially masking signals,
humpback whales and killer whales
have been observed to increase the
length of their songs (Miller et al., 2000;
Fristrup et al., 2003; Foote et al., 2004),
while right whales have been observed
to shift the frequency content of their
calls upward while reducing the rate of
calling in areas of increased
anthropogenic noise (Parks et al., 2007).
In some cases, animals may cease sound
production during production of
aversive signals (Bowles et al., 1994).
Cerchio et al. (2014) used passive
acoustic monitoring to document the
presence of singing humpback whales
off the coast of northern Angola and to
opportunistically test for the effect of
seismic survey activity on the number of
singing whales. Two recording units
were deployed between March and
December 2008 in the offshore
environment, and the numbers of
singers were counted every hour.
Generalized Additive Mixed Models
were used to assess the effect of survey
day (seasonality), hour (diel variation),
moon phase, and received levels of
noise (measured from a single pulse
during each ten minute sampled period)
on singer number. The number of
singers significantly decreased with
increasing received level of noise,
suggesting that humpback whale
breeding activity was disrupted to some
extent by the survey activity.
Castellote et al. (2012) reported
acoustic and behavioral changes by fin
whales in response to shipping and
airgun noise. Acoustic features of fin
whale song notes recorded in the
Mediterranean Sea and northeast
Atlantic Ocean were compared for areas
with different shipping noise levels and
traffic intensities and during a seismic
airgun survey. During the first 72 hours
of the survey, a steady decrease in song
received levels and bearings to singers
indicated that whales moved away from
the acoustic source and out of the study
area. This displacement persisted for a
time period well beyond the 10-day
duration of seismic airgun activity,
providing evidence that fin whales may
avoid an area for an extended period in
the presence of increased noise. The
authors hypothesize that fin whale
acoustic communication is modified to
compensate for increased background
noise and that a sensitization process
may play a role in the observed
temporary displacement.
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Seismic pulses at average received
levels of 131 dB re 1 mPa2-s caused blue
whales to increase call production (Di
Iorio and Clark, 2010). In contrast,
McDonald et al. (1995) tracked a blue
whale with seafloor seismometers and
reported that it stopped vocalizing and
changed its travel direction at a range of
10 km from the acoustic source vessel
(estimated received level 143 dB pk-pk).
Blackwell et al. (2013) found that
bowhead whale call rates dropped
significantly at onset of airgun use at
sites with a median distance of 41–45
km from the survey. Blackwell et al.
(2015) expanded this analysis to show
that whales actually increased calling
rates as soon as airgun signals were
detectable before ultimately decreasing
calling rates at higher received levels
(i.e., 10-minute SELcum of ∼127 dB).
Overall, these results suggest that
bowhead whales may adjust their vocal
output in an effort to compensate for
noise before ceasing vocalization effort
and ultimately deflecting from the
acoustic source (Blackwell et al., 2013,
2015). These studies demonstrate that
even low levels of noise received far
from the source can induce changes in
vocalization and/or behavior for
mysticetes.
Avoidance is the displacement of an
individual from an area or migration
path as a result of the presence of a
sound or other stressors, and is one of
the most obvious manifestations of
disturbance in marine mammals
(Richardson et al., 1995). For example,
gray whales are known to change
direction—deflecting from customary
migratory paths—in order to avoid noise
from seismic surveys (Malme et al.,
1984). Humpback whales showed
avoidance behavior in the presence of
an active seismic array during
observational studies and controlled
exposure experiments in western
Australia (McCauley et al., 2000).
Avoidance may be short-term, with
animals returning to the area once the
noise has ceased (e.g., Bowles et al.,
1994; Stone et al., 2000; Morton and
Symonds, 2002; Gailey et al., 2007).
Longer-term displacement is possible,
however, which may lead to changes in
abundance or distribution patterns of
the affected species in the affected
region if habituation to the presence of
the sound does not occur (e.g., Bejder et
al., 2006; Teilmann et al., 2006).
A flight response is a dramatic change
in normal movement to a directed and
rapid movement away from the
perceived location of a sound source.
The flight response differs from other
avoidance responses in the intensity of
the response (e.g., directed movement,
rate of travel). Relatively little
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information on flight responses of
marine mammals to anthropogenic
signals exist, although observations of
flight responses to the presence of
predators have occurred (Connor and
Heithaus, 1996). The result of a flight
response could range from brief,
temporary exertion and displacement
from the area where the signal provokes
flight to, in extreme cases, marine
mammal strandings (Evans and
England, 2001). However, it should be
noted that response to a perceived
predator does not necessarily invoke
flight (Ford and Reeves, 2008), and
whether individuals are solitary or in
groups may influence the response.
Behavioral disturbance can also
impact marine mammals in more subtle
ways. Increased vigilance may result in
costs related to diversion of focus and
attention (i.e., when a response consists
of increased vigilance, it may come at
the cost of decreased attention to other
critical behaviors such as foraging or
resting). These effects have generally not
been demonstrated for marine
mammals, but studies involving fish
and terrestrial animals have shown that
increased vigilance may substantially
reduce feeding rates (e.g., Beauchamp
and Livoreil 1997; Purser and Radford
2011). In addition, chronic disturbance
can cause population declines through
reduction of fitness (e.g., decline in
body condition) and subsequent
reduction in reproductive success,
survival, or both (e.g., Harrington and
Veitch 1992; Daan et al. 1996; Bradshaw
et al. 1998). However, Ridgway et al.
(2006) reported that increased vigilance
in bottlenose dolphins exposed to sound
over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions,
such as feeding, resting, traveling, and
socializing, on a diel cycle (24-hour
cycle). Disruption of such functions
resulting from reactions to stressors
such as sound exposure are more likely
to be significant if they last more than
one diel cycle or recur on subsequent
days (Southall et al., 2007).
Consequently, a behavioral response
lasting less than one day and not
recurring on subsequent days is not
considered particularly severe unless it
could directly affect reproduction or
survival (Southall et al., 2007). Note that
there is a difference between multi-day
substantive behavioral reactions and
multi-day anthropogenic activities. For
example, just because an activity lasts
for multiple days does not necessarily
mean that individual animals are either
exposed to activity-related stressors for
multiple days or, further, exposed in a
manner resulting in sustained multi-day
substantive behavioral responses.
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Stone (2015) reported data from at-sea
observations during 1,196 seismic
surveys from 1994 to 2010. When large
arrays of airguns (considered to be 500
cui or more) were firing, lateral
displacement, more localized
avoidance, or other changes in behavior
were evident for most odontocetes.
However, significant responses to large
arrays were found only for the minke
whale and fin whale. Behavioral
responses observed included changes in
swimming or surfacing behavior, with
indications that cetaceans remained
near the water surface at these times.
Cetaceans were recorded as feeding less
often when large arrays were active.
Behavioral observations of gray whales
during a seismic survey monitored
whale movements and respirations
pre-, during and post-seismic survey
(Gailey et al., 2016). Behavioral state
and water depth were the best ‘natural’
predictors of whale movements and
respiration and, after considering
natural variation, none of the response
variables were significantly associated
with seismic survey or vessel sounds.
Marine mammals are likely to avoid
the proposed activities, especially
harbor porpoises, while the harbor seals
might be attracted to them out of
curiosity. However, because the subbottom profilers and seismic equipment
operate from moving vessels, the area
(relative to the available habitat in Cook
Inlet) and time that this equipment
would be affecting a given location is
very small. Further, for mobile sources,
once an area has been surveyed, it is not
likely that it will be surveyed again,
therefore reducing the likelihood of
repeated geophysical and geotechnical
survey impacts within the survey area.
The isopleths for harassment for the
stationary sources considered in this
document are small relative to those for
mobile sources. Therefore, while the
sound is concentrated in the same area
for the duration of the activity (duration
of pile driving, VSP, etc), the amount of
area affected by noise levels which we
expect may cause harassment are small
relative to the mobile sources.
Additionally, animals may more
predictably avoid the area of the
disturbance as the source is stationary.
Overall duration of these sound sources
is still short and unlikely to cause more
than temporary disturbance.
We have also considered the potential
for severe behavioral responses such as
stranding and associated indirect injury
or mortality from Hilcorp’s use of high
resolution geophysical survey
equipment, on the basis of a 2008 mass
stranding of approximately one hundred
melon-headed whales in a Madagascar
lagoon system. An investigation of the
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event indicated that use of a highfrequency mapping system (12-kHz
multibeam echosounder) was the most
plausible and likely initial behavioral
trigger of the event, while providing the
caveat that there is no unequivocal and
easily identifiable single cause (Southall
et al., 2013). The investigatory panel’s
conclusion was based on (1) very close
temporal and spatial association and
directed movement of the survey with
the stranding event; (2) the unusual
nature of such an event coupled with
previously documented apparent
behavioral sensitivity of the species to
other sound types (Southall et al., 2006;
Brownell et al., 2009); and (3) the fact
that all other possible factors considered
were determined to be unlikely causes.
Specifically, regarding survey patterns
prior to the event and in relation to
bathymetry, the vessel transited in a
north-south direction on the shelf break
parallel to the shore, ensonifying large
areas of deep-water habitat prior to
operating intermittently in a
concentrated area offshore from the
stranding site. This may have trapped
the animals between the sound source
and the shore, thus driving them
towards the lagoon system. The
investigatory panel systematically
excluded or deemed highly unlikely
nearly all potential reasons for these
animals leaving their typical pelagic
habitat for an area extremely atypical for
the species (i.e., a shallow lagoon
system). Notably, this was the first time
that such a system has been associated
with a stranding event. The panel also
noted several site- and situation-specific
secondary factors that may have
contributed to the avoidance responses
that led to the eventual entrapment and
mortality of the whales. Specifically,
shoreward-directed surface currents and
elevated chlorophyll levels in the area
preceding the event may have played a
role (Southall et al., 2013). The report
also notes that prior use of a similar
system in the general area may have
sensitized the animals and also
concluded that, for odontocete
cetaceans that hear well in higher
frequency ranges where ambient noise is
typically quite low, high-power active
sonars operating in this range may be
more easily audible and have potential
effects over larger areas than low
frequency systems that have more
typically been considered in terms of
anthropogenic noise impacts. It is,
however, important to note that the
relatively lower output frequency,
higher output power, and complex
nature of the system implicated in this
event, in context of the other factors
noted here, likely produced a fairly
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unusual set of circumstances that
indicate that such events would likely
remain rare and are not necessarily
relevant to use of lower-power, higherfrequency systems more commonly used
for high resolution geophysical (HRG)
survey applications. The risk of similar
events recurring may be very low, given
the extensive use of active acoustic
systems used for scientific and
navigational purposes worldwide on a
daily basis and the lack of direct
evidence of such responses previously
reported.
3. Stress Responses—An animal’s
perception of a threat may be sufficient
to trigger stress responses consisting of
some combination of behavioral
responses, autonomic nervous system
responses, neuroendocrine responses, or
immune responses (e.g., Seyle, 1950;
Moberg 2000). In many cases, an
animal’s first and sometimes most
economical (in terms of energetic costs)
response is behavioral avoidance of the
potential stressor. Autonomic nervous
system responses to stress typically
involve changes in heart rate, blood
pressure, and gastrointestinal activity.
These responses have a relatively short
duration and may or may not have a
significant long-term effect on an
animal’s fitness.
Neuroendocrine stress responses often
involve the hypothalamus-pituitaryadrenal system. Virtually all
neuroendocrine functions that are
affected by stress—including immune
competence, reproduction, metabolism,
and behavior—are regulated by pituitary
hormones. Stress-induced changes in
the secretion of pituitary hormones have
been implicated in failed reproduction,
altered metabolism, reduced immune
competence, and behavioral disturbance
(e.g., Moberg 1987; Blecha 2000).
Increases in the circulation of
glucocorticoids are also equated with
stress (Romano et al. 2004).
The primary distinction between
stress (which is adaptive and does not
normally place an animal at risk) and
‘‘distress’’ is the cost of the response.
During a stress response, an animal uses
glycogen stores that can be quickly
replenished once the stress is alleviated.
In such circumstances, the cost of the
stress response would not pose serious
fitness consequences. However, when
an animal does not have sufficient
energy reserves to satisfy the energetic
costs of a stress response, energy
resources must be diverted from other
functions. This state of distress will last
until the animal replenishes its
energetic reserves sufficiently to restore
normal function.
Relationships between these
physiological mechanisms, animal
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behavior, and the costs of stress
responses are well-studied through
controlled experiments and for both
laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al.,
1998; Jessop et al., 2003; Lankford et al.,
2005). Stress responses due to exposure
to anthropogenic sounds or other
stressors and their effects on marine
mammals have also been reviewed (Fair
and Becker, 2000; Romano et al., 2002)
and, more rarely, studied in wild
populations (e.g., Romano et al., 2002).
For example, Rolland et al. (2012) found
that noise reduction from reduced ship
traffic in the Bay of Fundy was
associated with decreased stress in
North Atlantic right whales. These and
other studies lead to a reasonable
expectation that some marine mammals
will experience physiological stress
responses upon exposure to acoustic
stressors and that it is possible that
some of these would be classified as
‘‘distress.’’ In addition, any animal
experiencing TTS would likely also
experience stress responses (NRC,
2003).
In general, there are few data on the
potential for strong, anthropogenic
underwater sounds to cause nonauditory physical effects in marine
mammals. Such effects, if they occur at
all, would presumably be limited to
short distances and to activities that
extend over a prolonged period. The
available data do not allow
identification of a specific exposure
level above which non-auditory effects
can be expected (Southall et al., 2007).
There is no definitive evidence that any
of these effects occur even for marine
mammals in close proximity to an
anthropogenic sound source. In
addition, marine mammals that show
behavioral avoidance of survey vessels
and related sound sources, are unlikely
to incur non-auditory impairment or
other physical effects. NMFS does not
expect that the generally short-term,
intermittent, and transitory seismic and
geophysical surveys would create
conditions of long-term, continuous
noise and chronic acoustic exposure
leading to long-term physiological stress
responses in marine mammals. While
the noise from drilling related activities
are more continuous and longer term,
those sounds are generated at a much
lower level than the mobile sources
discussed earlier.
4. Auditory Masking—Sound can
disrupt behavior through masking, or
interfering with, an animal’s ability to
detect, recognize, or discriminate
between acoustic signals of interest (e.g.,
those used for intraspecific
communication and social interactions,
prey detection, predator avoidance,
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navigation) (Richardson et al., 1995;
Erbe et al., 2016). Masking occurs when
the receipt of a sound is interfered with
by another coincident sound at similar
frequencies and at similar or higher
intensity, and may occur whether the
sound is natural (e.g., snapping shrimp,
wind, waves, precipitation) or
anthropogenic (e.g., shipping, sonar,
seismic exploration) in origin. The
ability of a noise source to mask
biologically important sounds depends
on the characteristics of both the noise
source and the signal of interest (e.g.,
signal-to-noise ratio, temporal
variability, direction), in relation to each
other and to an animal’s hearing
abilities (e.g., sensitivity, frequency
range, critical ratios, frequency
discrimination, directional
discrimination, age or TTS hearing loss),
and existing ambient noise and
propagation conditions.
Under certain circumstances, marine
mammals experiencing significant
masking could also be impaired from
maximizing their performance fitness in
survival and reproduction. Therefore,
when the coincident (masking) sound is
man-made, it may be considered
harassment when disrupting or altering
critical behaviors. It is important to
distinguish TTS and PTS, which persist
after the sound exposure, from masking,
which occurs during the sound
exposure. Because masking (without
resulting in TS) is not associated with
abnormal physiological function, it is
not considered a physiological effect,
but rather a potential behavioral effect.
The frequency range of the potentially
masking sound is important in
determining any potential behavioral
impacts. For example, low-frequency
signals may have less effect on highfrequency echolocation sounds
produced by odontocetes but are more
likely to affect detection of mysticete
communication calls and other
potentially important natural sounds,
such as those produced by surf and
some prey species. The masking of
communication signals by
anthropogenic noise may be considered
as a reduction in the communication
space of animals (e.g., Clark et al., 2009)
and may result in energetic or other
costs as animals change their
vocalization behavior (e.g., Miller et al.
2000; Foote et al. 2004; Parks et al.
2007; Holt et al. 2009). Masking can be
reduced in situations where the signal
and noise come from different
directions (Richardson et al. 1995),
through amplitude modulation of the
signal, or through other compensatory
behaviors (Houser and Moore 2014).
Masking can be tested directly in
captive species (e.g., Erbe 2008) but, in
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wild populations, it must be either
modeled or inferred from evidence of
masking compensation. There are few
studies addressing real-world masking
sounds likely to be experienced by
marine mammals in the wild (e.g.,
Branstetter et al. 2013).
Masking affects both senders and
receivers of acoustic signals and can
potentially have long-term chronic
effects on marine mammals at the
population level as well as at the
individual level. Low-frequency
ambient sound levels have increased by
as much as 20 dB (more than three times
in terms of SPL) in the world’s ocean
from pre-industrial periods, with most
of the increase from distant commercial
shipping (Hildebrand 2009). All
anthropogenic sound sources, but
especially chronic and lower-frequency
signals (e.g., from vessel traffic),
contribute to elevated ambient sound
levels, thus intensifying masking.
Marine mammal communications
would not likely be masked appreciably
by the sub-profiler or seismic survey’s
signals given the directionality of the
signal and the brief period when an
individual mammal is likely to be
within its beam. The probability for
conductor pipe driving masking
acoustic signals important to the
behavior and survival of marine
mammal species is low. Vibratory pile
driving is also relatively short-term,
with rapid oscillations occurring for
short durations. It is possible that
vibratory pile driving resulting from this
proposed action may mask acoustic
signals important to the behavior and
survival of marine mammal species, but
the short-term duration and limited
affected area would result in
insignificant impacts from masking.
Any masking event that could possibly
rise to Level B harassment under the
MMPA would occur concurrently
within the zones of behavioral
harassment already estimated for
vibratory pile and conductor pipe
driving, and which have already been
taken into account in the exposure
analysis. Pile driving would occur for
limited durations across multiple
widely dispersed sites, thus we do not
anticipate masking to significantly affect
marine mammals.
Ship Strike
Vessel collisions with marine
mammals, or ship strikes, can result in
death or serious injury of the animal.
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
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bottom of a vessel, or an animal just
below the surface may be cut by a
vessel’s propeller. Superficial strikes
may not kill or result in the death of the
animal. These interactions are typically
associated with large whales (e.g., fin
whales), which are occasionally found
draped across the bulbous bow of large
commercial ships upon arrival in port.
Although smaller cetaceans are more
maneuverable in relation to large vessels
than are large whales, they may also be
susceptible to strike. The severity of
injuries typically depends on the size
and speed of the vessel, with the
probability of death or serious injury
increasing as vessel speed increases
(Knowlton and Kraus 2001; Laist et al.
2001; Vanderlaan and Taggart 2007;
Conn and Silber 2013). Impact forces
increase with speed, as does the
probability of a strike at a given distance
(Silber et al. 2010; Gende et al. 2011).
Pace and Silber (2005) also found that
the probability of death or serious injury
increased rapidly with increasing vessel
speed. Specifically, the predicted
probability of serious injury or death
increased from 45 to 75 percent as
vessel speed increased from 10 to 14 kn,
and exceeded 90 percent at 17 kn.
Higher speeds during collisions result in
greater force of impact, but higher
speeds also appear to increase the
chance of severe injuries or death
through increased likelihood of
collision by pulling whales toward the
vessel (Clyne and Kennedy, 1999;). In a
separate study, Vanderlaan and Taggart
(2007) analyzed the probability of lethal
mortality of large whales at a given
speed, showing that the greatest rate of
change in the probability of a lethal
injury to a large whale as a function of
vessel speed occurs between 8.6 and 15
kt. The chances of a lethal injury
decline from approximately 80 percent
at 15 kt to approximately 20 percent at
8.6 kt. At speeds below 11.8 kt, the
chances of lethal injury drop below 50
percent, while the probability
asymptotically increases toward one
hundred percent above 15 kt.
Hilcorp’s seismic vessels would travel
at approximately 4 knots (7.41 km/hour)
while towing seismic survey gear and a
maximum of 4.5 knots (8.3 km/hr) while
conducting geotechnical and geohazard
surveys (Faithweather, 2018). At these
speeds, both the possibility of striking a
marine mammal and the possibility of a
strike resulting in serious injury or
mortality are discountable. At average
transit speed, the probability of serious
injury or mortality resulting from a
strike is less than 50 percent. However,
the likelihood of a strike actually
happening is again discountable. Ship
strikes, as analyzed in the studies cited
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above, generally involve commercial
shipping, which is much more common
in both space and time than is
geophysical survey activity. Jensen and
Silber (2004) summarized ship strikes of
large whales worldwide from 1975–
2003 and found that most collisions
occurred in the open ocean and
involved large vessels (e.g., commercial
shipping). Commercial fishing vessels
were responsible for three percent of
recorded collisions, while no such
incidents were reported for geophysical
survey vessels during that time period.
It is possible for ship strikes to occur
while traveling at slow speeds. For
example, a hydrographic survey vessel
traveling at low speed (5.5 kt) while
conducting mapping surveys off the
central California coast struck and killed
a blue whale in 2009. The State of
California determined that the whale
had suddenly and unexpectedly
surfaced beneath the hull, with the
result that the propeller severed the
whale’s vertebrae, and that this was an
unavoidable event. This strike
represents the only such incident in
approximately 540,000 hours of similar
coastal mapping activity (p = 1.9 ×
10¥6; 95% CI = 0¥5.5 × 10¥6; NMFS,
2013b). In addition, a research vessel
reported a fatal strike in 2011 of a
dolphin in the Atlantic, demonstrating
that it is possible for strikes involving
smaller cetaceans to occur. In that case,
the incident report indicated that an
animal apparently was struck by the
vessel’s propeller as it was intentionally
swimming near the vessel. While
indicative of the type of unusual events
that cannot be ruled out, neither of these
instances represents a circumstance that
would be considered reasonably
foreseeable or that would be considered
preventable.
Although the likelihood of the vessel
striking a marine mammal is low, we
require a robust ship strike avoidance
protocol (see ‘‘Proposed Mitigation’’),
which we believe eliminates any
foreseeable risk of ship strike. We
anticipate that vessel collisions
involving a seismic data acquisition
vessel towing gear, while not
impossible, represent unlikely,
unpredictable events for which there are
no preventive measures. Given the
required mitigation measures, the
relatively slow speed of the vessel
towing gear, the presence of marine
mammal observers, and the short
duration of the survey, we believe that
the possibility of ship strike is
discountable. Further, were a strike of a
large whale to occur, it would be
unlikely to result in serious injury or
mortality. No incidental take resulting
from ship strike is anticipated, and this
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potential effect of the specified activity
will not be discussed further in the
following analysis.
Stranding
When a living or dead marine
mammal swims or floats onto shore and
becomes ‘‘beached’’ or incapable of
returning to sea, the event is a
‘‘stranding’’ (Geraci et al. 1999; Perrin
and Geraci 2002; Geraci and Lounsbury
2005). The legal definition for a
stranding under the MMPA is (A) a
marine mammal is dead and is (i) on a
beach or shore of the United States; or
(ii) in waters under the jurisdiction of
the United States (including any
navigable waters); or (B) a marine
mammal is alive and is (i) on a beach
or shore of the United States and is
unable to return to the water; (ii) on a
beach or shore of the United States and,
although able to return to the water, is
in need of apparent medical attention;
or (iii) in the waters under the
jurisdiction of the United States
(including any navigable waters), but is
unable to return to its natural habitat
under its own power or without
assistance.
Marine mammals strand for a variety
of reasons, such as infectious agents,
biotoxicosis, starvation, fishery
interaction, ship strike, unusual
oceanographic or weather events, sound
exposure, or combinations of these
stressors sustained concurrently or in
series. However, the cause or causes of
most strandings are unknown (Eaton,
1979; Best 1982). Numerous studies
suggest that the physiology, behavior,
habitat relationships, age, or condition
of cetaceans may cause them to strand
or might pre-dispose them to strand
when exposed to another phenomenon.
These suggestions are consistent with
the conclusions of numerous other
studies that have demonstrated that
combinations of dissimilar stressors
commonly combine to kill an animal or
dramatically reduce its fitness, even
though one exposure without the other
does not produce the same result (Fair
and Becker 2000; Moberg, 2000; Romero
2004; Sih et al. 2004).
Use of military tactical sonar has been
implicated in a majority of investigated
stranding events, although one
stranding event was associated with the
use of seismic airguns. This event
occurred in the Gulf of California,
coincident with seismic reflection
profiling by the R/V Maurice Ewing
operated by Lamont-Doherty Earth
Observatory (LDEO) of Columbia
University and involved two Cuvier’s
beaked whales (Hildebrand 2004). The
vessel had been firing an array of 20
airguns with a total volume of 8,500 cui
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(Hildebrand 2004). Most known
stranding events have involved beaked
whales, though a small number have
involved deep-diving delphinids or
sperm whales (e.g., Southall et al. 2013).
In general, long duration (∼1 second)
and high-intensity sounds (>235 dB
SPL) have been implicated in stranding
events (Hildebrand 2004). With regard
to beaked whales, mid-frequency sound
has been implicated in a few specific
cases (when causation can be
determined) (Hildebrand 2004).
Although seismic airguns create
predominantly low-frequency energy,
the signal does include a mid-frequency
component. Based on the information
presented above, we have considered
the potential for the proposed survey to
result in marine mammal stranding and
have concluded that, based on the best
available information, stranding is not
expected to occur.
Other Potential Impacts
Here, we briefly address the potential
risks due to entanglement and
contaminant spills. We are not aware of
any records of marine mammal
entanglement in towed arrays such as
those considered here. The discharge of
trash and debris is prohibited (33 CFR
151.51–77) unless it is passed through a
machine that breaks up solids such that
they can pass through a 25-mm mesh
screen. All other trash and debris must
be returned to shore for proper disposal
with municipal and solid waste. Some
personal items may be accidentally lost
overboard. However, U.S. Coast Guard
and Environmental Protection Act
regulations require operators to become
proactive in avoiding accidental loss of
solid waste items by developing waste
management plans, posting
informational placards, manifesting
trash sent to shore, and using special
precautions such as covering outside
trash bins to prevent accidental loss of
solid waste. There are no meaningful
entanglement risks posed by the
described activity, and entanglement
risks are not discussed further in this
document.
Marine mammals could be affected by
accidentally spilled diesel fuel from a
vessel associated with proposed survey
activities. Quantities of diesel fuel on
the sea surface may affect marine
mammals through various pathways:
Surface contact of the fuel with skin and
other mucous membranes, inhalation of
concentrated petroleum vapors, or
ingestion of the fuel (direct ingestion or
by the ingestion of oiled prey) (e.g.,
Geraci and St. Aubin, 1980, 1990).
However, the likelihood of a fuel spill
during any particular geophysical
survey is considered to be remote, and
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the potential for impacts to marine
mammals would depend greatly on the
size and location of a spill and
meteorological conditions at the time of
the spill. Spilled fuel would rapidly
spread to a layer of varying thickness
and break up into narrow bands or
windows parallel to the wind direction.
The rate at which the fuel spreads
would be determined by the prevailing
conditions such as temperature, water
currents, tidal streams, and wind
speeds. Lighter, volatile components of
the fuel would evaporate to the
atmosphere almost completely in a few
days. Evaporation rate may increase as
the fuel spreads because of the
increased surface area of the slick.
Rougher seas, high wind speeds, and
high temperatures also tend to increase
the rate of evaporation and the
proportion of fuel lost by this process
(Scholz et al., 1999). We do not
anticipate potentially meaningful effects
to marine mammals as a result of any
contaminant spill resulting from the
proposed survey activities, and
contaminant spills are not discussed
further in this document.
Similarly, marine mammals could be
affected by spilled hazardous materials
generated by the drilling process. Large
and small quantities of hazardous
materials, including diesel fuel and
gasoline, would be handled,
transported, and stored following the
rules and procedures described in the
Spill Prevention, Control, and
Countermeasure (SPCC) Plan. Spills and
leaks of oil or wastewater arising from
the proposed activities that reach
marine waters could result in direct
impacts to the health of exposed marine
mammals. Individual marine mammals
could show acute irritation or damage to
their eyes, blowhole or nares, and skin;
fouling of baleen, which could reduce
feeding efficiency; and respiratory
distress from the inhalation of vapors
(Geraci and St. Aubin 1990). Long-term
impacts from exposure to contaminants
to the endocrine system could impair
health and reproduction (Geraci and St.
Aubin 1990). Ingestion of contaminants
could cause acute irritation to the
digestive tract, including vomiting and
aspiration into the lungs, which could
result in pneumonia or death (Geraci
and St. Aubin 1990). However, the
measures outlined in Hilcorp’s spill
plan minimize the risk of a spill such
that we do not anticipate potentially
meaningful effects to marine mammals
as a result of oil spills from this activity,
and oil spills are not discussed further
in this document.
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Anticipated Effects on Marine Mammal
Habitat
Effects to Prey—Marine mammal prey
varies by species, season, and location
and, for some, is not well documented.
Fish react to sounds which are
especially strong and/or intermittent
low-frequency sounds. Short duration,
sharp sounds can cause overt or subtle
changes in fish behavior and local
distribution. Hastings and Popper (2005)
identified several studies that suggest
fish may relocate to avoid certain areas
of sound energy. Additional studies
have documented effects of pulsed
sound on fish, although several are
based on studies in support of
construction projects (e.g., Scholik and
Yan 2001, 2002; Popper and Hastings
2009). Sound pulses at received levels
of 160 dB may cause subtle changes in
fish behavior, although the behavioral
threshold currently observed is < 150
dB RMA re 1 mPa. SPLs of 180 dB may
cause noticeable changes in behavior
(Pearson et al. 1992; Skalski et al. 1992).
SPLs of sufficient strength have been
known to cause injury to fish and fish
mortality. The most likely impact to fish
from survey activities at the project area
would be temporary avoidance of the
area. The duration of fish avoidance of
a given area after survey effort stops is
unknown, but a rapid return to normal
recruitment, distribution and behavior
is anticipated.
Information on seismic airgun
impacts to zooplankton, which
represent an important prey type for
mysticetes, is limited. However,
McCauley et al. (2017) reported that
experimental exposure to a pulse from
a 150 cui airgun decreased zooplankton
abundance when compared with
controls, as measured by sonar and net
tows, and caused a two- to threefold
increase in dead adult and larval
zooplankton. Although no adult krill
were present, the study found that all
larval krill were killed after air gun
passage. Impacts were observed out to
the maximum 1.2 km range sampled.
The reaction of fish to airguns depends
on the physiological state of the fish,
past exposures, motivation (e.g.,
feeding, spawning, migration), and other
environmental factors. While we agree
that some studies have demonstrated
that airgun sounds might affect the
distribution and behavior of some
fishes, potentially impacting foraging
opportunities or increasing energetic
costs (e.g., Fewtrell and McCauley,
2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al.,
2017), other studies have shown no or
slight reaction to airgun sounds (e.g.,
Pena et al., 2013; Wardle et al., 2001;
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12353
Jorgenson and Gyselman, 2009; Cott et
al., 2012).
In general, impacts to marine mammal
prey are expected to be limited due to
the relatively small temporal and spatial
overlap between the proposed survey
and any areas used by marine mammal
prey species. The proposed activities
would occur over a relatively short time
period in a given area and would occur
over a very small area relative to the
area available as marine mammal
habitat in Cook Inlet. We do not have
any information to suggest the proposed
survey area represents a significant
feeding area for any marine mammal,
and we believe any impacts to marine
mammals due to adverse effects to their
prey would be insignificant due to the
limited spatial and temporal impact of
the proposed activities. However,
adverse impacts may occur to a few
species of fish and to zooplankton.
Packard et al. (1990) showed that
cephalopods were sensitive to particle
motion, not sound pressure, and
Mooney et al. (2010) demonstrated that
squid statocysts act as an accelerometer
through which particle motion of the
sound field can be detected. Auditory
injuries (lesions occurring on the
statocyst sensory hair cells) have been
reported upon controlled exposure to
low-frequency sounds, suggesting that
cephalopods are particularly sensitive to
low-frequency sound (Andre et al.,
2011; Sole et al., 2013). However, these
controlled exposures involved long
exposure to sounds dissimilar to airgun
pulses (i.e., 2 hours of continuous
exposure to 1-second sweeps, 50–400
Hz). Behavioral responses, such as
inking and jetting, have also been
reported upon exposure to lowfrequency sound (McCauley et al.,
2000b; Samson et al., 2014).
Indirect impacts from spills or leaks
could occur through the contamination
of lower-trophic-level prey, which could
reduce the quality and/or quantity of
marine mammal prey. In addition,
individuals that consume contaminated
prey could experience long-term effects
to health (Geraci and St. Aubin 1990).
However, the likelihood of spills and
leaks, as described above, is low. This
likelihood, in combination with
Hilcorp’s spill plan to reduce the risk of
hazardous material spills, is such that
its effect on prey is not considered
further in this document.
Acoustic Habitat—Acoustic habitat is
the soundscape—which encompasses
all of the sound present in a particular
location and time, as a whole—when
considered from the perspective of the
animals experiencing it. Animals
produce sound for, or listen for sounds
produced by, conspecifics
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(communication during feeding, mating,
and other social activities), other
animals (finding prey or avoiding
predators) and the physical
environment (finding suitable habitats,
navigating). Together, sounds made by
animals and the geophysical
environment (e.g., produced by
earthquakes, lightning, wind, rain,
waves) make up the natural
contributions to the total acoustics of a
place. These acoustic conditions,
termed acoustic habitat, are one
attribute of an animal’s total habitat.
Soundscapes are also defined by, and
acoustic habitat influenced by, the total
contribution of anthropogenic sound.
This may include incidental emissions
from sources such as vessel traffic or
may be intentionally introduced to the
marine environment for data acquisition
purposes (as in the use of airgun arrays
or other sources). Anthropogenic noise
varies widely in its frequency content,
duration, and loudness and these
characteristics greatly influence the
potential habitat-mediated effects to
marine mammals (please see also the
previous discussion on masking under
‘‘Acoustic Effects’’), which may range
from local effects for brief periods of
time to chronic effects over large areas
and for long durations. Depending on
the extent of effects to habitat, animals
may alter their communications signals
(thereby potentially expending
additional energy) or miss acoustic cues
(either conspecific or adventitious). For
more detail on these concepts see, e.g.,
Barber et al., 2010; Pijanowski et al.
2011; Francis and Barber 2013; Lillis et
al. 2014.
Problems arising from a failure to
detect cues are more likely to occur
when noise stimuli are chronic and
overlap with biologically relevant cues
used for communication, orientation,
and predator/prey detection (Francis
and Barber 2013). Although the signals
emitted by seismic airgun arrays are
generally low frequency, they would
also likely be of short duration and
transient in any given area due to the
nature of these surveys. Sub-bottom
profiler use is also expected to be short
term and not concentrated in one
location for an extended period of time.
The activities related to exploratory
drilling, while less transitory in nature,
are anticipated to have less severe
effects due to lower source levels and
therefore smaller disturbance zones than
the mobile sources considered here.
Nonetheless, we acknowledge the
general addition of multiple sound
source types into the area, which are
expected to have intermittent impacts
on the soundscape, typically of
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relatively short duration in any given
area.
In summary, activities associated with
the proposed action are not likely to
have a permanent, adverse effect on any
fish habitat or populations of fish
species or on the quality of acoustic
habitat. Thus, any impacts to marine
mammal habitat are not expected to
cause significant or long-term
consequences for individual marine
mammals or their populations.
and, (4) and the number of days of
activities. We note that while these
basic factors can contribute to a basic
calculation to provide an initial
prediction of takes, additional
information that can qualitatively
inform take estimates is also sometimes
available (e.g., previous monitoring
results or average group size). Below, we
describe the factors considered here in
more detail and present the proposed
take estimate.
Estimated Take
This section provides an estimate of
the number of incidental takes proposed
for authorization through this proposed
rule, which will inform both NMFS’
consideration of ‘‘small numbers’’ and
the negligible impact determination.
Harassment is the only type of take
expected to result from these activities.
Except with respect to certain activities
not pertinent here, section 3(18) of the
MMPA defines ‘‘harassment’’ as: Any
act of pursuit, torment, or annoyance
which (i) has the potential to injure a
marine mammal or marine mammal
stock in the wild (Level A harassment);
or (ii) has the potential to disturb a
marine mammal or marine mammal
stock in the wild by causing disruption
of behavioral patterns, including, but
not limited to, migration, breathing,
nursing, breeding, feeding, or sheltering
(Level B harassment).
Authorized takes would primarily be
by Level B harassment, as use of seismic
survey and construction equipment has
the potential to result in disruption of
behavioral patterns for individual
marine mammals. There is also some
potential for auditory injury (Level A
harassment) to result from equipment
such as seismic airguns, primarily for
mysticetes and high frequency species,
because predicted auditory injury zones
are larger than for mid-frequency
species and otariids. Auditory injury is
unlikely to occur for mid-frequency
cetaceans. The proposed mitigation and
monitoring measures are expected to
minimize the severity of such taking to
the extent practicable.
As described previously, no mortality
is anticipated or proposed to be
authorized for this activity. Below we
describe how the take is estimated.
Generally speaking, we estimate take
by considering: (1) Acoustic thresholds
above which NMFS believes the best
available science indicates marine
mammals will be behaviorally harassed
or incur some degree of permanent
hearing impairment; (2) the area or
volume of water that will be ensonified
above these levels in a day; (3) the
density or occurrence of marine
mammals within these ensonified areas;
Acoustic Thresholds
Using the best available science,
NMFS has developed acoustic
thresholds that identify the received
level of underwater sound above which
exposed marine mammals would be
reasonably expected to experience
behavioral disturbance (equated to Level
B harassment) or to incur PTS of some
degree (equated to Level A harassment).
Level B Harassment for non-explosive
sources—Though significantly driven by
received level, the onset of behavioral
disturbance from anthropogenic noise
exposure is also informed to varying
degrees by other factors related to the
source (e.g., frequency, predictability,
duty cycle), the environment (e.g.,
bathymetry), and the receiving animals
(hearing, motivation, experience,
demography, behavioral context) and
can be difficult to predict (Southall et
al., 2007, Ellison et al., 2012). Based on
the available science and the practical
need to use a threshold based on a factor
that is both predictable and measurable
for most activities, NMFS uses a
generalized acoustic threshold based on
received level to estimate the onset of
behavioral disturbance rising to the
level of Level B Harassment. NMFS
predicts that marine mammals are likely
to experience behavioral disturbance
sufficient to constitute Level B
harassment when exposed to
underwater anthropogenic noise above
received levels of 120 dB re 1 mPa (rms)
for continuous (e.g., vibratory piledriving, drilling) and above 160 dB re 1
mPa (rms) for non-explosive impulsive
(e.g., seismic airguns) or intermittent
(e.g., scientific sonar) sources.
Hilcorp’s proposed activity includes
the use of continuous (vibratory pile
driving, water jet) and impulsive
(seismic airguns, sub-bottom profiler,
conductor pipe driving, VSP) sources,
and therefore the 120 and 160 dB re 1
mPa (rms) are applicable.
Level A harassment for non-explosive
sources—NMFS’ Technical Guidance
for Assessing the Effects of
Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies
dual criteria to assess auditory injury
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airguns, sub-bottom profiler, conductor
pipe driving, VSP) and non-impulsive
(vibratory pile driving, water jet)
sources.
These thresholds for PTS are provided
in the table below. The references,
analysis, and methodology used in the
BILLING CODE 3510–22–C
was calculated by multiplying the
distances (in km) to the NMFS
thresholds (Level A harassment
distances from the User spreadsheet and
Level B harassment distances to the
160dB isopleth) on both sides of the
vessel by the distance of the line (in km)
to be surveyed each day. The in-water
source line is 6 km in length and only
one line will be surveyed each day.
Ensonified Area
Here, we describe operational and
environmental parameters of the activity
that will feed into identifying the area
ensonified above the acoustic
thresholds, which include source levels
and transmission loss coefficient.
2D Seismic Survey—The area of
ensonification for the 2D seismic survey
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development of the thresholds are
described in NMFS 2018 Technical
Guidance, which may be accessed at:
https://www.nmfs.noaa.gov/pr/acoustics/
guidelines.htm.
BILLING CODE 3510–22–P
Therefore, the line length surveyed each
day for the 2D seismic survey is 6 km.
3D Seismic Survey—The area of
ensonification for the 3D seismic survey
was calculated by multiplying the
distances (in km) to the NMFS
thresholds by the distance of the line (in
km) to be surveyed each day. The line
length is approximately 27.78 km (15
nm), which will take approximately
3.75 hrs to survey at a vessel speed of
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EP01AP19.000
(Level A harassment) to five different
marine mammal groups (based on
hearing sensitivity) as a result of
exposure to noise from two different
types of sources (impulsive or nonimpulsive). Hilcorp’s proposed activity
includes the use of impulsive (seismic
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4 knots (7.5 km/hr) with a turn of 1.5
hrs. In a 24-hr period, assuming no
delays, the survey team will be able to
collect data on 4.5 lines or
approximately 127 km. The distance in
between line lengths is 3.7 km (2 nm),
so there will be overlap of the area of
Level B ensonification, resulting in an
overestimation of exposures. Instead,
the total daily area of ensonification was
calculated using GIS. The Level B radii
were added to each track line estimated
to be traveled in a 24-hour period, and
when there was overlapping areas, the
resulting polygons were merged to one
large polygon to eliminate the chance
that the areas could be summed
multiple times over the same area. The
results of the overall area are
summarized in Table 6 below and
shown on Figure 19 in the application
(only showing Level B).
Geohazard Sub-bottom Profiler for
Well Sites—The area of ensonification
for the sub-bottom profiler used during
the geohazard surveys for the well sites
was calculated by multiplying the
distances (in km) to the NMFS
thresholds by the distance of the line (in
km) to be surveyed each day. The
maximum required monitoring distance
from the well site per BOEM is 2,400 m
(or a total length of 4,800 m in diameter)
and the minimum transect width is 150
m, so the total maximum number of
transects to be surveyed is 32 (4,800 m/
150 m). The total distance to be
surveyed is 153.60 km (4.8 km × 32
transects). Assuming a vessel speed of 4
knots (7.41 km/hr), it will take
approximately 0.65 hrs (38 minutes) to
survey a single transect of 4.8 km (time
= distance/rate). Assuming the team is
surveying for 50 percent of the day (or
12 hrs), the total number of days it will
take to survey the total survey grid is
7.77 days (0.65 hr × 12 hr). Similar to
the 3D seismic survey, there will be
overlap in the Level B ensonification of
the sound because of the distance in
between the transects. However,
because the area and grid to be surveyed
depends on the results of the 3D survey
and the specific location, Hilcorp
Alaska proposes to use this overestimate
for purposes of this proposed
rulemaking. The total line length to be
surveyed per day is 19.76 km (total
distance to be surveyed 153.6 km/total
days 7.77).
Geohazard Sub-bottom Profiler for
Pipeline Maintenance—The area of
ensonification for the sub-bottom
profiler used during geohazard surveys
for the pipeline maintenance was
calculated by multiplying the distances
(in km) to the NMFS thresholds by the
distance of the line (in km) to be
surveyed each day. The assumed
transect grid is 300 m by 300 m with
150 m transect widths, so the total to be
surveyed is 2,400 m (2.4 km). Assuming
a vessel speed of 4 knots (7.41 km/hr),
it will take approximately 0.08 hrs (4.86
min) to survey a single transect. The
total number of days it will take to
survey the grid is 1 day. Similar to the
3D seismic survey, there will be overlap
of the Level B ensonification area
because of the distance in between the
transects. However, because the area
and grid to be surveyed depends on the
results of the 3D survey and the specific
location, Hilcorp Alaska proposes to use
this overestimate for purposes of this
proposed rule. The total line length to
be surveyed per day is 2.4 km.
Other sources—For stationary
sources, area of a circle to the relevant
Level A or Level B harassment isopleths
was used to determine ensonified area.
These sources include: Conductor pipe
driving, VSP, vibratory sheet pile
driving, and water jets.
When the NMFS Technical Guidance
(2016) was published, in recognition of
the fact that ensonified area/volume
could be more technically challenging
to predict because of the duration
component in the new thresholds, we
developed a User Spreadsheet that
includes tools to help predict a simple
isopleth that can be used in conjunction
with marine mammal density or
occurrence to help predict takes by
Level A harassment. We note that
because of some of the assumptions
included in the methods used for these
tools, we anticipate that isopleths
produced are typically going to be
overestimates of some degree, which
may result in some degree of
overestimate of Level A harassment
take. However, these tools offer the best
way to predict appropriate isopleths
when more sophisticated 3D modeling
methods are not available; and NMFS
continues to develop ways to
quantitatively refine these tools and will
qualitatively address the output where
appropriate. For stationary sources such
as conductor pipe driving or vibratory
pile driving, NMFS User Spreadsheet
predicts the closest distance at which, if
a marine mammal remained at that
distance the whole duration of the
activity, it would not incur PTS. For
mobile sources such as seismic airguns
or sub-bottom profilers, the User
Spreadsheet predicts the closest
distance at which a stationary animal
would not incur PTS if the sound source
traveled by the animal in a straight line
at a constant speed. Inputs used in the
User Spreadsheet, and the resulting
isopleths are reported below (Tables 4,
5, and 6). Transmission loss used for all
calculation was practical spreading (15
LogR).
TABLE 4—NMFS USER SPREADSHEET INPUTS
Activity
Type of source
Source level
2D/3D seismic ...............
mobile, impulsive ..........
Sub-bottom profiler .......
Pipe driving ...................
VSP ...............................
Vibratory sheet pile driving.
Water jet ........................
mobile, impulsive ..........
stationary, impulsive .....
stationary, impulsive .....
stationary, non-impulsive.
stationary, non-impulsive.
217 dB peak @100 m; 185
dB SEL @100 m.
212 dB rms @1 m ................
195 dB rms @55 m ..............
227 dB rms @1m .................
160 dB rms @10 m ..............
176 dB rms @1 m ................
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Weighting
factor
adjustment
Source
velocity
Pulse
duration
Repetition rate
1 kHz ..........
2.05 m/s .....
N/A .........
every 6 s ..............
N/A.
4 kHz ..........
2 kHz ..........
1 kHz ..........
2.5 kHz .......
2.05 m/s .....
N/A .............
N/A .............
N/A .............
0.02 s .....
0.02 s .....
0.02 s .....
N/A .........
every 0.30 s .........
600 strikes/hr ........
Every 6 s ..............
N/A .......................
N/A.
2 hrs/day.
4 hrs/day.
4 hrs/day.
2 kHz ..........
N/A .............
N/A .........
N/A .......................
0.5 hrs/day.
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01APP2
Duration
per day
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TABLE 5—CALCULATED DISTANCES TO NMFS LEVEL A HARASSMENT THRESHOLDS
Level A
Activity
2D/3D seismic .......
Sub-bottom profiler
Pipe driving ...........
VSP .......................
Vibratory sheet pile
driving ................
Water jet ...............
Hydraulic grinder ...
Tugs towing ..........
Low frequency cetaceans
Mid frequency cetaceans
Impulsive
Impulsive
219 dB
pk
183 dB
SEL
74
<1
1
3
399
77
134
11,217
............
............
............
............
............
............
............
............
Nonimpulsive
High frequency cetaceans
Nonimpulsive
199 dB SEL
230 dB
pk
185 dB
SEL
....................
....................
....................
....................
14
<1
<1
<1
<1
4
103
96
15
14
1
<1
............
............
............
............
............
............
............
............
Impulsive
198 dB SEL
202 dB
pk
155 dB
SEL
....................
....................
....................
....................
1,000
5
19
46
45
1,108
3,435
2,617
1
<1
<1
<1
............
............
............
............
............
............
............
............
Phocids
Nonimpulsive
Impulsive
Otariids
Non-impulsive
173 dB SEL
218 dB
pk
185 dB
SEL
....................
....................
....................
....................
86
<1
2
4
66
48
1,543
3,371
22
13
1
<1
............
............
............
............
............
............
............
............
Impulsive
Nonimpulsive
201 dB SEL
232 dB
pk
203 dB
SEL
219 dB SEL
....................
....................
....................
....................
10
<1
<1
<1
1
<1
112
249
....................
....................
....................
....................
9
8
<1
<1
............
............
............
............
............
............
............
............
<1
1
<1
<1
TABLE 6—CALCULATED DISTANCES TO NMFS LEVEL B THRESHOLDS
Level B
Activity
2D/3D seismic ..............................................................................................................................................
Sub-bottom profiler ......................................................................................................................................
Pipe driving ..................................................................................................................................................
VSP ..............................................................................................................................................................
Vibratory sheet pile driving ..........................................................................................................................
Water jet ......................................................................................................................................................
Hydraulic grinder ..........................................................................................................................................
Tugs towing .................................................................................................................................................
Marine Mammal Occurrence
In this section we provide the
information about the presence, density,
or group dynamics of marine mammals
that will inform the take calculations.
Beluga whale—Historically, beluga
whales were observed in both upper and
lower Cook Inlet in June and July (Rugh
et al. 2000). However, between 1993 and
1995, less than 3 percent of all of the
annual sightings were in the lower inlet,
south of the East and West Forelands,
hardly any (one whale in Tuxedni Bay
in 1997 and two in Kachemak Bay in
2001) have been seen in the lower inlet
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during these surveys 1996–2016 (Rugh
et al. 2005; Shelden et al. 2013, 2015,
2017). Because of the extremely low
sighting rates, it is difficult to provide
an accurate estimate of density for
beluga whales in the mid and lower
Cook Inlet region.
Goetz et al. (2012b) developed a
habitat-based model to estimate Cook
Inlet beluga density based on seasonally
collected data. The model was based on
sightings, depth soundings, coastal
substrate type, environmental
sensitivity index, anthropogenic
disturbance, and anadromous fish
streams to predict densities throughout
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Impulsive
Non-impulsive
160 dB rms
120 dB rms
7,330
2,929
1,630
2,470
..............................
..............................
<1
..............................
..............................
..............................
..............................
..............................
4,642
5,411
398
2,514
Cook Inlet. The result of this work is a
beluga density map of Cook Inlet, which
predicts spatially explicit density
estimates for Cook Inlet belugas. Figure
1 shows the Goetz et al. (2012b)
estimates with the project area. Using
data from the GIS files provided by
NMFS and the different project
locations, the resulting estimated
density is shown in Table 7. The water
jets would be used on pipelines
throughout the middle Cook Inlet
region, so the higher density for the
Trading Bay area was used.
BILLING CODE 3510–22–P
E:\FR\FM\01APP2.SGM
01APP2
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Goograpflic Region
Hllco rp leases:
OOIVII!HHl Slllte
Waters
Map of Petition Area
with Beluga Density
Modeling by Area
T!lQ-OH-TOW Swath
Figure 1. Beluga whale density as defined by Goetz et al. (2012b) in action area.
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Densities resulting from this model
are summarized in Table 7 below.
TABLE 7—COOK INLET BELUGA WHALE DENSITY BASED ON GOETZ HABITAT MODEL
Beluga whale density
(ind/km2)
Project location
Project activity
Lower Cook Inlet (OCS) .................................................
Lower Cook Inlet (east side) ..........................................
Iniskin Bay area ..............................................................
North Cook Inlet Unit ......................................................
Trading Bay area ............................................................
3D seismic, geohazard, pipe driving ..........................................
2D seismic ..................................................................................
Sheet pile driving ........................................................................
Geohazard, pipe driving .............................................................
Geohazard, pipe driving, water jets ............................................
Other Marine Mammals—Density
estimates of species other than beluga
whales were estimated from the NMFS
June aerial surveys conducted for beluga
whales between 2000 and 2016 (Rugh et
al. 2005; Shelden et al. 2013, 2015,
2017). Although these surveys are only
flown for a few days in one month, they
represent the best available relatively
long-term dataset for marine mammal
sightings in Cook Inlet. Table 8 below
summarizes the maximum marine
mammals observed for each year for the
survey and area covered. To estimate
density, the total number of individuals
per species sighted during surveys was
divided by the distance flown on the
surveys. The total number of animals
0.00
0.00–0.011106
0.024362
0.001664
0.004453–0.015053
observed accounts for both lower and
upper Cook Inlet, so this density
estimate is higher than what is
anticipated for the lower Cook Inlet
area. There are no density estimates
available for California sea lions for
Cook Inlet so largest potential group size
was used.
TABLE 8—DENSITY ESTIMATES FOR MARINE MAMMALS IN ACTION AREA
Estimated density
(# marine
mammals/km2) 3
Species
Beluga whale:
Lower and Middle Cook Inlet 1 ...............................................................................................................................................
Lower Cook Inlet 2 ..................................................................................................................................................................
North Cook Inlet Unit 2 ............................................................................................................................................................
Trading Bay area 2 ..................................................................................................................................................................
Iniskin Peninsula 2 ..................................................................................................................................................................
Humpback whale ...........................................................................................................................................................................
Minke whale ...................................................................................................................................................................................
Gray whale .....................................................................................................................................................................................
Fin whale .......................................................................................................................................................................................
Killer whale ....................................................................................................................................................................................
Dall’s porpoise ...............................................................................................................................................................................
Harbor porpoise .............................................................................................................................................................................
Harbor seal ....................................................................................................................................................................................
Steller sea lion ...............................................................................................................................................................................
0.00006
0.01111
0.00166
0.01505
0.02436
0.00009
0.00000
0.00001
0.00005
0.00011
0.00006
0.00037
0.00655
0.00035
1 NMFS
aerial survey combined lower and middle Cook Inlet density.
et al. 2012(b) habitat-based model density.
3 When using data from NMFS aerial surveys, the survey year with the greatest calculated density was used to calculate exposures.
No density available for California sea lions in Cook Inlet.
2 Goetz
Duration
The duration was estimated for each
activity and location. For some projects,
like the 3D seismic survey, the design of
the project is well developed; therefore,
the duration is well-defined. However,
for some projects, the duration is not
well developed, such as activities
around the lower Cook Inlet well sites,
because the duration depends on the
results of previous studies and
equipment availability. Our
assumptions regarding these activities,
which were used to estimate duration,
are discussed below.
2D Seismic—A single vessel is
capable of acquiring a source line in
approximately 1–2 hrs and only one
source line will be collected in one day
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to allow for all the node deployments
and retrievals, and intertidal and land
zone shot holes drilling. There are up to
10 source lines, so assuming all
operations run smoothly, there will only
be 2 hrs per day over 10 days of airgun
activity. The duration that was used to
assess exposures from the 2D seismic
survey is 10 days.
3D Seismic—The total anticipated
duration of the survey is 45–60 days,
including delays due to equipment,
weather, tides, and marine mammal
shut downs. The duration that was used
to assess exposures from the 3D seismic
survey is 60 days.
Geohazard Surveys (Sub-bottom
profiler)—Assuming surveying occurs
50 percent of the day (or 12 hrs), the
total number of days it will take to
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survey the total geohazard survey grid
for a single well is 7.77 days. This
duration was multiplied by the number
of wells per site resulting in 31.1 days
for the four Lower Cook Inlet OCS wells,
7.7 days for the North Cook Inlet Unit
well, and 15.5 days for the two Trading
Bay area wells.
The total number of days it will take
to survey the geohazard survey grid for
a pipeline maintenance is 1 day. This
duration was multiplied by the number
of anticipated surveys per year (high
estimate of 3 per year), for a total of 3
days.
Drive Pipe—It takes approximately 3
days to install the drive pipe per well
with only 25 percent of the day
necessary for actual pipe driving. This
duration was multiplied by the number
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of wells per site resulting in 3 days for
the four lower Cook Inlet wells and 1.5
days for the two Trading Bay area wells.
Drive pipe installation is not part of the
activities planned at the North Cook
Inlet site.
VSP—It takes approximately 2 days to
perform the VSP per well with only 25
percent of the day necessary for actual
seismic work. VSP is not part of the
plugging and abandonment (P&A)
activities at the North Cook Inlet site.
This duration was multiplied by the
number of wells per site, resulting in 2
days for the four lower Cook Inlet wells
and 1 day for the two Trading Bay area
wells.
Vibratory Sheet Pile Driving—The
total number of days expected to install
the sheet pile dock face using vibratory
hammers on the rock causeway is 14
days with only 25 percent of the day for
actual pile driving, resulting in 3.5 days
of sound for the Iniskin project.
Water jets—Water jets are only used
when needed for maintenance;
therefore, the annual duration was
estimated to evaluate exposures. Each
water jet event was estimated to be 30
minutes or less in duration. We
acknowledge that due to the short
duration of this activity, it is possible
that take will not occur—however, we
are including consideration of potential
take to conservatively ensure coverage
for the applicant. It was estimated that
a water jet event occurs 3 times a
month, resulting in only 1.5 hrs per
month of water jet operation. Water jets
are used during ice-free months, so this
duration was multiplied by 7 months
(May–November) resulting in 10.5 days.
Take Calculation and Estimation
Here we describe how the information
provided above is brought together to
produce a quantitative take estimate.
The numbers of each marine mammal
species that could potentially be
exposed to sounds associated with the
proposed activities that exceed NMFS’
acoustic Level A and B harassment
criteria were estimated per type of
activity and per location. The specific
years when these activities might occur
are not known at this time, so this
method of per activity per location
allows for flexibility in operations and
provides NMFS with appropriate
information for assessing potential
exposures. Individual animals may be
exposed to received levels above our
harassment thresholds more than once
per day, but NMFS considers animals
only ‘‘taken’’ once per day. Exposures
refer to any instance in which an animal
is exposed to sound sources above
NMFS’ Level A or Level B harassment
thresholds. The estimated exposures
(without any mitigation) per activity per
location were calculated by multiplying
the density of marine mammals (# of
marine mammals/km2) by the area of
ensonification (km2) and the duration
(days per year). These results of these
calculations are presented in Tables 9
and 10 below.
TABLE 9—ESTIMATED NUMBER OF LEVEL A EXPOSURES PER ACTIVITY AND LOCATION
3D
seismic
2D
seismic
Iniskin
vibratory
sheet pile
LCI 1
LCI 1
LCI 1
Species
Humpback whale
Minke whale ......
Gray whale ........
Fin whale ...........
Killer whale ........
Beluga whale .....
Dall’s porpoise ...
Harbor porpoise
Harbor seal ........
Steller sea lion ..
1 LCI—Lower
6.80
0.04
0.29
1.19
0.07
0.00
1.31
37.25
287.11
0.70
0.05
0.00
0.00
0.01
0.00
0.01
0.01
0.29
2.26
0.01
Sub-bottom profiler
Water
jets 6
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
MCI 4
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.04
0.09
0.00
LCI 1
0.09
0.00
0.00
0.02
0.00
0.00
0.11
3.20
7.39
0.00
NCI 2
0.02
0.00
0.00
0.00
0.00
0.00
0.03
0.80
1.85
0.00
Pipe driving
TB 3
0.04
0.00
0.00
0.01
0.00
0.02
0.06
1.60
3.69
0.00
LCI 1
Vertical seismic
profiling
TB 3
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.05
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.02
0.00
LCI 1
5.97
0.03
0.25
1.05
0.00
0.00
0.03
0.81
5.80
0.01
TB 3
2.98
0.02
0.13
0.52
0.00
0.00
0.01
0.40
2.90
0.01
Cook Inlet Wells, 2 NCI—North Cook Inlet Unit well, 3 TB = Trading Bay wells, 4 MCI—Middle Cook Inlet Pipeline Maintenance.
TABLE 10—ESTIMATED NUMBER OF LEVEL B EXPOSURES PER ACTIVITY AND LOCATION
3D
seismic
2D
seismic
Iniskin
vibratory
sheet pile
LCI 1
LCI 1
LCI 1
Species
Humpback whale
Minke whale ......
Gray whale ........
Fin whale ...........
Killer whale ........
Beluga whale .....
Dall’s porpoise ...
Harbor porpoise
Harbor seal ........
Steller sea lion ..
1 LCI—Lower
85.43
0.45
3.60
14.99
29.02
0.00
7.42
211.70
11,255.01
366.99
0.83
0.00
0.04
0.15
0.28
0.00
0.07
2.06
109.38
3.57
0.64
0.00
0.03
0.11
0.22
8.24
0.06
1.58
84.17
2.74
0.01
0.00
0.00
0.00
0.00
0.05
0.00
0.02
0.83
0.03
MCI 4
0.04
0.00
0.00
0.01
0.01
0.00
0.00
0.10
5.24
0.17
LCI 1
3.40
0.02
0.14
0.60
1.15
0.00
0.30
8.42
447.52
14.59
NCI 2
0.85
0.00
0.04
0.15
0.29
0.75
0.07
2.10
111.88
3.65
Pipe driving
TB 3
1.70
0.01
0.07
0.30
0.58
13.54
0.15
4.21
223.76
7.30
LCI 1
0.05
0.00
0.00
0.01
0.02
0.00
0.00
0.12
6.23
0.20
Vertical seismic
profiling
TB 3
0.02
0.00
0.00
0.00
0.01
0.19
0.00
0.06
3.11
0.10
LCI 1
0.07
0.00
0.00
0.01
0.02
0.00
0.01
0.18
9.53
0.31
TB 3
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
Cook Inlet Wells, 2 NCI—North Cook Inlet Unit well, 3 TB = Trading Bay wells, 4 MCI—Middle Cook Inlet Pipeline Maintenance.
The take estimates by activity and
location discussed in the previous
section are not representative of the
estimated takes 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
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the previous activity). This results in
much uncertainty in the timing,
duration, and complete scope of work.
Each year, the applicant will submit an
application for an LOA with the specific
details of the planned work for that year
with estimated take numbers. The most
realistic scenario used to estimate
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annual takes includes 3D seismic
surveys in the first season, activities for
one well in the second season in lower
Cook Inlet, as well as the plugging and
abandonment activities in North Cook
Inlet Unit and the two wells in the
Trading Bay area. For the third season,
we have included activities for drilling
E:\FR\FM\01APP2.SGM
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two wells in lower Cook Inlet and the
final well in the fourth season. Table 17
summarizes the activities included in
this second scenario.
TABLE 11—SUMMARY OF ACTIVITIES CONSIDERED BY YEAR
Year
Activity
May 2019–2020 .....................................................
3D seismic ....................................................................................................
Geohazard ....................................................................................................
Sheet pile driving ..........................................................................................
Pipeline maintenance (geohazard, water jet, grinder) .................................
Drilling activities (tugs, geohazard, pipe driving, VSP) at all 1 well .............
Drilling activities (tugs, geohazard, pipe driving, VSP) at 2 wells ................
P&A activities (tugs, geohazard) at 1 well ...................................................
Pipeline maintenance (geohazard, water jet, grinder) .................................
Drilling activities (tugs, geohazard, pipe driving, VSP) at 2wells .................
2D seismic ....................................................................................................
Pipeline maintenance (geohazard, water jet, grinder) .................................
Drilling activities (tugs, geohazard, pipe driving, VSP) at 1 well .................
Pipeline maintenance (geohazard, water jet, grinder) .................................
Pipeline maintenance (geohazard, water jet, grinder) .................................
April 2020–2021 ....................................................
April 2021–2022 ....................................................
April 2022–2023 ....................................................
April 2023–2024 ....................................................
Area
LCI.
LCI.
Iniskin (LCI).
MCI.
LCI.
TB.
NCI.
MCI
LCI.
LCI.
MCI.
LCI.
MCI.
MCI.
LCI—Lower Cook Inlet Wells, NCI—North Cook Inlet Unit well, TB = Trading Bay wells, MCI—Middle Cook Inlet Pipeline Maintenance.
TABLE 12—ESTIMATED EXPOSURES FOR FIRST YEAR OF ACTIVITY
Level A
Species
Humpback
whale .........
Minke whale ..
Gray whale ....
Fin whale .......
Killer whale ....
Beluga whale
Dall’s porpoise
Harbor porpoise ..........
Harbor seal ....
Steller sea lion
California sea
lion .............
MCI
pipeline
geohazard
MCI
pipeline
water jet
Level B
LCI subbottom
profiler
LCI 3D
seismic
LCI
sheet pile
driving
MCI
pipeline
geohazard
Total
MCI
pipeline
water jet
LCI subbottom
profiler
LCI 3D
seismic
LCI
sheet pile
driving
Total
0
0
0
0
0
0
0
0
0
0
0
0
0
0
6.8
0.04
0.29
0.29
1.19
0
1.31
0.09
0
0
0.02
0
0
0.11
0
0
0
0
0
0
0
6.89
0.04
0.29
0.31
1.19
0
1.42
0.04
0
0
0.01
0.01
0
0
0.15
0
0.01
0.03
0.05
1.2
0.01
85.43
0.45
3.60
3.60
14.99
0
7.42
3.4
0.02
0.14
0.60
1.15
0
0.3
2.56
0.01
0.11
0.45
0.87
32.98
0.22
91.57
0.48
3.86
4.68
17.08
34.18
7.95
0.04
0.09
0
0
0
0
37.25
287.11
0.7
3.2
7.39
0
0
0
0
40.49
294.58
0.7
0.1
5.24
0.17
0.37
19.85
0.65
211.70
11255.01
366.99
8.42
447.52
14.59
6.33
336.67
10.98
226.92
12064.29
393.38
0
0
0
0
0
0
0
0
0
0
0
0
TABLE 13—ESTIMATED EXPOSURES FOR SECOND YEAR OF ACTIVITY
Level A
Humpback whale
Minke whale ......
Gray whale ........
Fin whale ...........
Killer whale ........
Beluga whale .....
Dall’s porpoise ...
Harbor porpoise
Harbor seal ........
Steller sea lion ..
California sea
lion .................
Level B
MCI pipeline
geohazard
MCI pipeline
water jet
LCI
geohazard,
pipe driving,
VSP
(1 well only)
0
0
0
0
0
0
0
0.04
0.09
0
0
0
0
0
0
0
0
0
0
0
1.51
0.01
0.06
0.27
0
0
0.04
1
3.31
0
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
0
0
....................
0
Level A
Humpback whale
Minke whale ......
Gray whale ........
Fin whale ...........
Killer whale ........
Beluga whale .....
VerDate Sep<11>2014
TB
geohazard
(2 wells)
TB pipe
driving
(2 wells)
TB VSP
.02
0
0
0
0
0.02
.04
0
0
0.01
0
0.02
0
0
0
0
0
0
2.98
0.02
0.13
0.52
0
0
Jkt 247001
MCI pipeline
water jet
LCI
geohazard,
pipe driving,
VSP
(1 well only)
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
0.04
0
0
0.01
0.01
0
0
0.10
5.24
0.17
0.15
0
0.01
0.03
0.05
1.2
0.01
0.37
19.85
0.65
0.97
0.01
0.04
0.17
0.33
0
0.08
2.4
127.64
4.16
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
....................
0
0
0
....................
....................
Subtotal for
all activities
NCI
geohazard
(1 well)
20:49 Mar 29, 2019
MCI pipeline
geohazard
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4.57
0.02
0.19
0.8
0
0.04
Sfmt 4702
Level B
Subtotal for
all activities
NCI
geohazard
(1 well)
TB
geohazard
(2 wells)
TB pipe
driving
(2 wells)
TB VSP
0.85
0
0.04
0.15
0.85
0.85
1.7
0.01
0.07
0.3
0.58
13.54
0.09
0
0
0.02
0.03
0.75
0.14
0
0.01
0.03
0.05
1.15
E:\FR\FM\01APP2.SGM
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3.95
0.02
0.17
0.69
1.9
17.5
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TABLE 13—ESTIMATED EXPOSURES FOR SECOND YEAR OF ACTIVITY—Continued
Level A
Dall’s porpoise ...
Harbor porpoise
Harbor seal ........
Steller sea lion ..
California sea
lion .................
Level B
MCI pipeline
geohazard
MCI pipeline
water jet
LCI
geohazard,
pipe driving,
VSP
(1 well only)
0.02
0.02
0.02
0.02
0.06
1.6
3.69
0
0
0
0.02
0
0.01
0.4
2.9
0.01
0
0
0
0
MCI pipeline
geohazard
MCI pipeline
water jet
LCI
geohazard,
pipe driving,
VSP
(1 well only)
0.13
3.07
10.04
0.03
0.85
0.85
0.85
0.85
0.15
4.21
223.76
7.3
0.01
0.23
12.46
0.41
0.01
0.36
19.07
0.62
1.12
8.52
408.87
14.15
0
0
0
0
0
0
TABLE 14—ESTIMATED EXPOSURES FOR THIRD YEAR OF ACTIVITY
Level A
Humpback whale
Minke whale ......
Gray whale ........
Fin whale ...........
Killer whale ........
Beluga whale .....
Dall’s porpoise ...
Harbor porpoise
Harbor seal ........
Steller sea lion ..
California sea
lion .................
Level B
MCI pipeline
geohazard
MCI pipeline
water jet
LCI
geohazard,
pipe driving,
VSP
(2 wells
only)
0
0
0
0
0
0
0
0.04
0.09
0
0
0
0
0
0
0
0
0
0
0
3.03
0.02
0.13
0.53
0
0
0.07
2
6.62
0.01
0.05
0
0
0.01
0
0.01
0.01
0.29
2.26
0.01
0
0
0
0
MCI pipeline
geohazard
MCI pipeline
water jet
LCI
geohazard,
pipe driving,
VSP
(2 wells
only)
3.08
0.02
0.13
0.54
0
0.01
0.08
2.34
8.97
0.01
0.04
0
0
0.01
0.01
0
0
0.1
5.24
0.17
0.15
0
0.01
0.03
0.05
1.2
0.01
0.37
19.85
0.65
1.94
0.01
0.08
0.34
0.66
0
0.17
4.8
255.28
8.32
0.83
0
0.04
0.15
0.28
4.8
0.07
2.06
109.38
3.57
2.96
0.02
0.12
0.52
1.01
6.09
0.26
7.33
389.76
12.71
0
0
0
0
0
0
MCI pipeline
geohazard
MCI pipeline
water jet
LCI
geohazard,
pipe driving,
VSP
(1 well only)
0.04
0
0
0.01
0.01
0
0
0.1
5.24
0.17
0
0.15
0
0.01
0.03
0.05
1.2
0.01
0.37
19.85
0.65
0
0.97
0.01
0.04
0.17
0.33
0
0.08
2.40
127.64
4.16
0
Total
LCI 2D
seismic
Total
LCI 2D
seismic
TABLE 15—ESTIMATED EXPOSURES FOR FOURTH YEAR OF ACTIVITY
Level A
Humpback whale ...............................................
Minke whale ......................................................
Gray whale ........................................................
Fin whale ...........................................................
Killer whale ........................................................
Beluga whale .....................................................
Dall’s porpoise ...................................................
Harbor porpoise ................................................
Harbor seal ........................................................
Steller sea lion ..................................................
California sea lion .............................................
Level B
MCI pipeline
geohazard
MCI pipeline
water jet
LCI
geohazard,
pipe driving,
VSP
(1 well only)
0
0
0
0
0
0
0
0.04
0.09
0
0
0
0
0
0
0
0
0
0
0
0
0
1.51
0.01
0.06
0.27
0
0
0.04
1
3.31
0
0
Total
1.52
0.01
0.06
0.27
0
0
0.04
1.04
3.40
0
0
Total
1.16
0.01
0.05
0.2
0.39
1.2
0.10
2.87
152.74
4.98
0
TABLE 16—ESTIMATED EXPOSURES FOR FIFTH YEAR OF ACTIVITY
Level A
MCI pipeline
geohazard
Humpback whale .....................................
Minke whale .............................................
Gray whale ...............................................
Fin whale ..................................................
Killer whale ...............................................
Beluga whale ...........................................
Dall’s porpoise .........................................
6.09+Harbor porpoise ..............................
Harbor seal ..............................................
Steller sea lion .........................................
California sea lion ....................................
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water jet
0
0
0
0
0
0
0
0.04
0.09
0
0
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Frm 00034
0
0
0
0
0
0
0
0
0
0
0
Fmt 4701
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geohazard
Total
Sfmt 4702
0
0
0
0
0
0
0
0.04
0.09
0
0
E:\FR\FM\01APP2.SGM
0.04
0
0
0.01
0.01
0
0
0.1
5.24
0.17
0
01APP2
MCI pipeline
water jet
0.15
0
0.01
0.03
0.05
1.2
0.01
0.37
19.85
0.65
0
Total
0.19
0
0.01
0.03
0.06
1.2
0.02
0.47
25.10
0.82
0
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TABLE 17—ESTIMATED MAXIMUM EXPOSURES THAT MAY BE AUTHORIZED IN ONE YEAR, BASED ON FIRST YEAR OF
ACTIVITY
Level A
Species
Total
calculated
Level B
Total
authorized
Percent of
stock
Total
calculated
Total
authorized
Humpback whale .....................................
Minke whale .............................................
Gray whale ..............................................
Fin whale .................................................
Killer whale ..............................................
6.89
0.04
0.29
0.31
1.19
7
0
0
0
0
0.63
0
0
0
0
91.57
0.48
3.86
4.68
17.08
92
1
4
5
17
Beluga whale ...........................................
Dall’s porpoise .........................................
Harbor porpoise .......................................
Harbor seal ..............................................
Steller sea lion .........................................
California sea lion ....................................
0
1.42
40.49
294.58
0.7
0
0
2
40
295
1
0
0
0.0024
0.13
1.1
0
0
34.18
7.95
226.92
12064.29
393.38
0
30
8
227
6,000
394
5
Percent of
stock
8.31
0.08
0.02
0.16
0.72 (resident)
or 2.90
(transient)
9.62
0.01
0.73
21.91
0.74
0
TABLE 18—TOTAL EXPOSURES CALCULATED AND REQUESTED OVER THE 5-YEAR REGULATIONS
Calculated Exposures
Group
Level A
LF Cetaceans ....................................
MF Cetaceans ...................................
HF Cetaceans ...................................
Phocids .............................................
Otariids ..............................................
Humpback whale ..............................
Minke whale .....................................
Gray whale .......................................
Fin whale ..........................................
Killer whale .......................................
Beluga whale ....................................
Dall’s porpoise ..................................
Harbor porpoise ...............................
Harbor seal .......................................
Steller sea lion .................................
California sea lion ............................
Based on the results of the acoustic
harassment analysis, Hilcorp Alaska is
requesting a small number of takes by
Level A harassment for humpback
whales, Dall’s porpoises, harbor
porpoises, Steller sea lions, and harbor
seals. Hilcorp Alaska does not anticipate
that any of the activities will result in
mortality or serious injury to marine
mammals, but these species may be
exposed to levels exceeding the Level A
harassment thresholds. Seals are highly
curious and exhibit high tolerance for
anthropogenic activity, so they are
likely to enter within the larger Level A
harassment isopleths. Porpoises are
difficult to observer at greater distances
and usually only remain in an area for
a short period of time. The total
requested takes by Level A harassment
are for 16 humpback whales, 5 Dall’s
porpoises, 47 harbor porpoises, and 317
harbor seals. Note this is not a request
for annual takes, but total takes over the
5-year period.
The requested takes by Level B
harassment for minke and gray whale
are rounded up to 5 animals, based on
the assumption that one could be taken
per year for five years. The requested
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Species
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16.06
0.08
0.68
1.91
0.2
0.05
1.67
46.97
317.07
0.76
0
takes by Level B harassment for
humpback whales is 100 animals,
although it is not expected to approach
this number as humpbacks are easily
observable during monitoring efforts.
The requested takes by Level B
harassment for killer whales are
rounded up to 20 animals to allow for
small groups. The requested takes by
Level B harassment for Dall’s and harbor
porpoise are rounded up to 10 and 246
animals, respectively, due to the
inconspicuous nature of porpoises.
The requested takes by Level B
harassment for harbor seals is 6,847
animals. The estimated number of
instances of takes by Level B harassment
of 13,041 resulting from the calculations
outlined above is an overestimate due to
the inclusion of haul out sites numbers
in the underlying density estimate used
to calculate take. Using the daily
ensonified area x number of survey days
x density method results in a reasonable
estimate of the instances of take, but
likely significantly overestimates the
number of individual animals expected
to be taken. With most species, even this
overestimated number is still very
small, and additional analysis is not
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Level B
99.82
0.53
4.21
6.93
20.44
60.17
9.45
246.12
13040.77
426.04
0
Level A
Level B
16
0
0
0
0
0
5
47
317
5
0
100
5
5
7
20
35
10
246
6847
426
5
really necessary to ensure minor
impacts. However, because of the
number and density of harbor seals in
the area, a more accurate understanding
of the number of individuals likely
taken is necessary to fully analyze the
impacts and ensure that the total
number of harbor seals taken is small.
As described below, based on
monitoring results from the area, it is
likely that the modeled number of
estimated instances of harbor seal take
referenced above is overestimated. The
density estimate from NMFS aerial
surveys includes harbor seal haulouts
far south of the action area that may
never move to an ensonified area.
Further, we believe that we can
reasonably estimate the comparative
number of individual harbor seals that
will likely be taken, based both on
monitoring data, operational
information, and a general
understanding of harbor seal habitat
use.
Using the daily ensonified area ×
number of survey days × density, the
number of instances of exposure above
the 160-dB threshold estimated for
Hilcorp’s activity in Cook Inlet is large.
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However, when we examine monitoring
data from previous activities, it is clear
this number is an overestimate—
compared to both aerial and vessel
based observation efforts. Apache’s
monitoring report from 2012 details that
they saw 2,474 harbor seals from 29
aerial flights (over 29 days) in the
vicinity of the survey during the month
of June, which is the peak month for
harbor seal haulout. In surveying the
literature, correction factors to account
for harbor seals in water based on land
counts vary from 1.2 to 1.65 (Harvey &
Goley, 2011). Using the most
conservative factor of 1.65 (allowing us
to consider that some of the other
individuals on land may have entered
the water at other points in day), if
Apache saw 2,474 seals hauled out then
there were an estimated 1,500 seals in
the water during those 29 days. To
account for the limited number of
surveys (29 surveys), NMFS
conservatively multiplied the number of
seals by 5.5 to estimate the number of
seals that might have been seen if the
aerial surveys were conducted for 160
days. This yields an estimate of 8,250
instances of seal exposure in the water,
which is far less than the exposure
estimate resulting from Hilcorp’s
calculations. NMFS further reduced the
estimate given the context of the
activity. The activity with the highest
potential take of harbor seal according
to calculations is 3D seismic surveying,
primarily due to the high source levels.
However, the 3D seismic surveying is
occurring primarily offshore, which is
also the area where they are least likely
to encounter harbor seals. The
calculated exposures from 3D seismic
surveying account for 92 percent of the
total calculated harbor seal exposures
across the five years of the project,
accounting for a high proportion of the
takes allocated to deeper water seismic
activity which is less likely to spatially
overlap with harbor seals. That the
number of potential instances of
exposure is likely less than calculated is
also supported by the visual
observations from Protected Species
Observers (PSOs) on board vessels.
PSOs in Cook Inlet sighted a total of 285
seals in water over 147 days of activity,
which would rise to about 310 if
adjusted to reflect 160 days of effort.
Given the size of the disturbance zone
for these activities, it is likely that not
all harbor seals that were exposed were
seen by PSOs. However 310 is still far
less than the estimate given by the
density calculations.
Further, based on the residential
nature of harbor seals and the number
of offshore locations included in
Hilcorp’s project, where harbor seals are
unlikely to reside, NMFS estimated the
number of individual harbor seals
exposed, given the instances of
exposures. Given these multiple
methods, as well as the behavioral
preferences of harbor seals for haulouts
in certain parts of the Inlet (Montgomery
et al., 2007), and high concentrations at
haulouts in the lower Inlet, it is
unreasonable to expect that more than
25 percent of the population, or 6,847
individuals, will be taken by Level B
harassment during Hilcorp’s activity.
Therefore, we estimate that 6,847
individuals are taken, which equates to
25 percent of the estimated abundance
in NMFS stock assessment report.
Effects of Specified Activities on
Subsistence Uses of Marine Mammals
The availability of the affected marine
mammal stocks or species for
subsistence uses may be impacted by
this activity. The subsistence uses that
may be affected and the potential
impacts of the activity on those uses are
described below. Measures included in
this proposed rule to reduce the impacts
of the activity on subsistence uses are
described in the Proposed Mitigation
section. Last, the information from this
section and the Proposed Mitigation
section is analyzed to determine
whether the necessary findings may be
made in the Unmitigable Adverse
Impact Analysis and Determination
section.
The ADF&G conducted studies to
document the harvest and use of wild
resources by residents of communities
on the east and west sides of Cook Inlet
(Jones and Kostick 2016). Data on wild
resource harvest and use were collected,
including basic information about who,
what, when, where, how, and how
much wild resources are being used to
develop fishing and hunting
opportunities for Alaska residents.
Tyonek was surveyed in 2013 (Jones et
al., 2015), and Nanwalek, Port Graham,
and Seldovia were surveyed in 2014
(Jones and Kostick 2016). Marine
mammals were harvested by three
(Seldovia, Nanwalek, Port Graham) of
the four communities but at relatively
low rates. The harvests consisted of
harbor seals, Steller sea lions, and
northern sea otters (Enhydra lutris), the
latter of which is managed by the U.S.
Fish and Wildlife Service and not
mentioned further.
TABLE 19—MARINE MAMMAL HARVEST BY TYONEK IN 2013 AND NIKISKI, PORT GRAHAM, SELDOVIA, AND NANWALEK IN
2014
Village
Tyonek .....................................................
Seldovia ...................................................
Nanwalek .................................................
Port ...........................................................
Graham ....................................................
In Tyonek, harbor seals were
harvested between June and September
by 6 percent of the households (Jones et
al. 2015). Seals were harvested in
several areas, encompassing an area
stretching 20 miles along the Cook Inlet
coastline from the McArthur River Flats
north to the Beluga River. Seals were
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Households
attempting
harvest
number
(% of
residents)
Harvest
(pounds per
capita)
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Number of marine mammals harvested
Harbor seal
Northern sea
otter
Beluga whale
2
1
11
6 (6%)
2 (1%)
17 (7%)
6
5
22
0
0
6
0
3
1
0
0
0
8
27 (18%)
16
1
24
0
searched for or harvested in the Trading
Bay areas as well as from the beach
adjacent to Tyonek (Jones et al. 2015).
In Seldovia, the harvest of harbor seals
(5 total) occurred exclusively in
December (Jones and Kostick 2016).
In Nanwalek, 22 harbor seals were
harvested in 2014 between March and
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October, the majority of which occur in
April. Nanwalek residents typically
hunt harbor seals and Steller sea lions
at Bear Cove, China Poot Bay, Tutka
Bay, Seldovia Bay, Koyuktolik Bay, Port
Chatam, in waters south of Yukon
Island, and along the shorelines close to
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Nanwalek, all south of the Petition
region (Jones and Kosick 2016).
According to the results presented in
Jones and Kostick (2016) in Port
Graham, harbor seals were the most
frequently used marine mammal; tribal
members harvested 16 in the survey
year. Harbor seals were harvested in
January, February, July, August,
September, November, and December.
Steller sea lions were used noticeably
less and harvested in November and
December.
The Cook Inlet beluga whale has
traditionally been hunted by Alaska
Natives for subsistence purposes. For
several decades prior to the 1980s, the
Native Village of Tyonek residents were
the primary subsistence hunters of Cook
Inlet beluga whales. During the 1980s
and 1990s, Alaska Natives from villages
in the western, northwestern, and North
Slope regions of Alaska either moved to
or visited the south-central region and
participated in the yearly subsistence
harvest (Stanek 1994). From 1994 to
1998, NMFS estimated 65 whales per
year were taken in this harvest,
including those successfully taken for
food, and those struck and lost. NMFS
has concluded that this number is high
enough to account for the estimated 14
percent annual decline in population
during this time (Hobbs et al. 2008).
Actual mortality may have been higher,
given the difficulty of estimating the
number of whales struck and lost during
the hunts. In 1999, a moratorium was
enacted (Pub. L. 106–31) prohibiting the
subsistence take of Cook Inlet beluga
whales except through a cooperative
agreement between NMFS and the
affected Alaska Native organizations.
On October 15, 2008, NMFS
published a final rule that established
long-term harvest limits on the Cook
Inlet beluga whales that may be taken by
Alaska Natives for subsistence purposes
(73 FR 60976). That rule prohibits
harvest for a 5-year period (2008–2012),
if the average abundance for the Cook
Inlet beluga whales from the prior five
years (2003–2007) is below 350 whales.
The next 5-year period that could allow
for a harvest (2013–2017) would require
the previous five-year average (2008–
2012) to be above 350 whales. Since the
Cook Inlet beluga whale harvest was
regulated in 1999 requiring cooperative
agreements, five beluga whales have
been struck and harvested. Those beluga
whales were harvested in 2001 (one
animal), 2002 (one animal), 2003 (one
animal), and 2005 (two animals). The
Native Village of Tyonek agreed not to
hunt or request a hunt in 2007, when no
co-management agreement was to be
signed (NMFS 2008).
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The 2008 Cook Inlet Beluga Whale
Subsistence Harvest Final Supplemental
Environmental Impact Statement
(NMFS 2008a) authorizes how many
beluga whales can be taken during a 5year interval based on the 5-year
population estimates and 10-year
measure of the population growth rate.
Based on the 2008–2012 5-year
abundance estimates, no hunt occurred
between 2008 and 2012 (NMFS 2008a).
The Cook Inlet Marine Mammal
Council, which managed the Alaska
Native Subsistence fishery with NMFS,
was disbanded by a unanimous vote of
the Tribes’ representatives on June 20,
2012. No harvest has occurred since
then and no harvest is likely in 2018.
Residents of the Native Village of
Tyonek are the primary subsistence
users in Knik Arm area (73 FR 60976).
No households hunted beluga whale
locally in Cook Inlet due to conservation
concerns (Jones et al. 2015). The
proposed project should not have any
effect because no beluga harvest has
taken place since 2005, and beluga
hunts are not expected during the next
five-year period.
Proposed Mitigation
In order to issue an LOA under
section 101(a)(5)(A) of the MMPA,
NMFS must set forth the permissible
methods of taking pursuant to such
activity, and other means of effecting
the least practicable impact on such
species or stock and its habitat, paying
particular attention to rookeries, mating
grounds, and areas of similar
significance, and on the availability of
such species or stock for taking for
certain subsistence uses. NMFS
regulations require applicants for
incidental take authorizations to include
information about the availability and
feasibility (economic and technological)
of equipment, methods, and manner of
conducting such activity or other means
of effecting the least practicable adverse
impact upon the affected species or
stocks and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or
may not be appropriate to ensure the
least practicable adverse impact on
species or stocks and their habitat, as
well as subsistence uses where
applicable, we carefully consider two
primary factors:
(1) The manner in which, and the
degree to which, the successful
implementation of the measure(s) is
expected to reduce impacts to marine
mammals, marine mammal species or
stocks, and their habitat, as well as
subsistence uses. This considers the
nature of the potential adverse impact
being mitigated (likelihood, scope,
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range). It further considers the
likelihood that the measure will be
effective if implemented (probability of
accomplishing the mitigating result if
implemented as planned), the
likelihood of effective implementation
(probability implemented as planned)
and;
(2) the practicability of the measures
for applicant implementation, which
may consider such things as cost,
impact on operations, and, in the case
of a military readiness activity,
personnel safety, practicality of
implementation, and impact on the
effectiveness of the military readiness
activity.
Mitigation for Marine Mammals and
Their Habitat
Hilcorp has reviewed mitigation
measures employed during seismic
research surveys authorized by NMFS
under previous incidental harassment
authorizations, as well as recommended
best practices in Richardson et al.
(1995), Pierson et al. (1998), Weir and
Dolman (2007), Nowacek et al. (2013),
Wright (2014), and Wright and
Cosentino (2015), and has incorporated
a suite of proposed mitigation measures
into their project description based on
the above sources.
To reduce the potential for
disturbance from acoustic stimuli
associated with the activities, Hilcorp
has proposed to implement the
following mitigation measures for
marine mammals:
(1) Vessel-based and shore-based
visual mitigation monitoring;
(2) Establishment of a marine
mammal exclusion zone (EZ) and safety
zone (SZ);
(3) Shutdown procedures;
(4) Power down procedures;
(5) Ramp-up procedures; and
(6) Vessel strike avoidance measures.
In addition to the measures proposed
by Hilcorp, NMFS has proposed the
following mitigation measures: Aerial
overflights for pre-clearance and
seasonal closure of the Susitna River
Delta.
Exclusion and safety zones—The
Exclusion Zone (EZ) is defined as the
area in which all operations are shut
down in the event a marine mammal
enters or is about to enter this zone
based on distances to the Level A
harassment threshold or what can be
effectively monitored for the species.
The Safety Zone (SZ) is an area larger
than the EZ and is defined as the area
within which operations may power
down in the event a marine mammal
enters or is about to enter, and may be
considered a Level B harassment. For all
activities, if a marine mammal for which
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take is not authorized is seen within or
entering the SZ, operations will shut
down. A minimum 10 meter shutdown
zone will be observed for all in-water
construction and heavy machinery.
The distances for the EZ and SZ for
the activities are summarized in Table
20 and described in the following text:
(1) The distances to the Level A
harassment thresholds for the 2D/3D
seismic activity were calculated using
the methods described above and are
indicated in Table 5 above. As in several
recent IHAs authorizing take from
seismic surveys (e.g., five surveys in the
Atlantic (82 FR 26244) and NSF (83 FR
44578)), we have proposed a more
standardized 500-m EZ, which is
practicable to implement and minimizes
the likelihood of injury or more severe
behavioral responses. The SZ for all
marine mammals is 1,000 m. The
distances to the thresholds for the sub-
bottom profiler were calculated using
the methods described above. The EZ
for all marine mammals is rounded up
to 100 m.
(2) The distances to the Level A
harassment thresholds for the pipe
driving were calculated using methods
above and the distance to the Level B
harassment threshold is based on
Illingworth & Rodkin (2014)
measurements of 1,600 m to the 160 dB
zone. The EZ for all marine mammals is
rounded up to 100 m. The SZ for all
marine mammals is 1,600 m.
(3) The distances to the Level A
harassment thresholds for VSP were
calculated using methods described in
above and the distance to the Level B
harassment threshold is based on
Illingworth & Rodkin (2014)
measurements of 2,470 m to the 160 dB
zone. The EZ for all marine mammals is
500 m.
(4) The distances to the Level A and
B harassment thresholds for the
vibratory sheet pile driving were
calculated using the methods described
above. The EZ for all marine mammals
is 100 m. The SZ for all marine
mammals is 2,500 m.
(5) The distances to the Level A
harassment thresholds for the water jet
were calculated using methods
described above and the distance to the
Level B harassment threshold is based
on Austin (2017) measurements of 860
m to the 120 dB zone. The EZ for all
marine mammals is rounded up to 15 m.
The SZ for all marine mammals is 860
m.
(6) NMFS proposes that Hilcorp shut
down if a beluga is observed within or
entering the EZ or SZ for seismic airgun
or sub-bottom profiler use.
TABLE 20—RADII OF EXCLUSION ZONE (EZ) AND SAFETY ZONE (SZ) FOR HILCORP’S ACTIVITIES
Exclusion
zone (EZ)
radius
(m)
Activity
2D/3D seismic survey ..............................................................................................................................................
Sub-bottom profilers ................................................................................................................................................
Pipe driving ..............................................................................................................................................................
VSP ..........................................................................................................................................................................
Sheet pile driving .....................................................................................................................................................
Water jet ..................................................................................................................................................................
PSO Placement—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 VSP, 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.
Seismic and Geohazard Survey
Mitigation
Aircraft (Seismic only)—NMFS
proposes to require aerial overflights to
clear the intended area of seismic
survey activity of beluga whales on a
daily basis. Hilcorp will fly over the
action area searching for belugas prior to
ramp up of seismic airguns and ramp up
will not commence until the flights have
confirmed the area appears free of
beluga whales. This measure would
only apply to 2D and 3D seismic
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surveying, not to other sound sources
related to geohazard survey or well
construction.
Clearing the Exclusion Zone—Prior to
the start of daily activities for which
take has been requested or if activities
have been stopped for longer than a 30minute period, the PSOs will ensure the
EZ is clear of marine mammals for a
period of 30 minutes. Clearing the EZ
means no marine mammals have been
observed within the EZ for that 30minute period. If any marine mammals
have been observed within the EZ, ramp
up cannot start until the marine
mammal has left the EZ or has not been
observed for a 30-minute period prior to
the start of the survey.
Power Downs—A power down
procedure involves reducing the
number of airguns in use, which
reduces the SZ radius and was proposed
by Hilcorp in their application. In
contrast, a shut down procedure occurs
when all airgun activity is suspended
immediately. During a power down, a
mitigation airgun is operated for no
longer than three hours. Operation of
the mitigation gun allows the size of the
SZ to decrease to the size of the EZ for
marine mammals other than beluga
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500
100
100
500
100
15
Safety
zone (SZ)
radius
(m)
1,000
1,000
1,600
2,500
2,500
860
whales. If a marine mammal is detected
outside the original SZ but is likely to
enter that zone, the airguns may be
powered down before the animal is
within the safety radius, as an
alternative to a complete shutdown.
Likewise, if a marine mammal is already
within the original SZ when first
detected, the airguns may be powered
down if the PSOs determine it is a
reasonable alternative to an immediate
shutdown. If a marine mammal is
already within the EZ when first
detected, the airguns will be shut down
immediately.
Following a power down, airgun
activity will not resume until the marine
mammal has cleared the original SZ.
The animal will be considered to have
cleared the original SZ if it:
• Is visually observed to have left the
SZ,
• Has not been seen within the SZ for
15 min in the case of pinnipeds, and
porpoises, or
• Has not been seen within the SZ for
30 min in the case of cetaceans.
Shutdowns—A shutdown is defined
as suspending all airgun and sub-bottom
profiler activities. Shutdowns are not
implemented for the other activities in
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Hilcorp’s petition that are unlikely to
result in take as they are not easily
turned off instantaneously. The
operating airguns or profiler will be shut
down completely if a marine mammal is
within or enters the EZ. The operations
will shut down completely if a beluga
whale is sighted within or entering the
SZ or EZ. The shutdown procedure
must be accomplished within several
seconds (of a ‘‘one shot’’ period) of the
determination that a marine mammal is
within or enters the EZ.
Following a shutdown, airgun or subbottom profiler activity may be
reactivated only after the protected
species has been observed exiting the
applicable 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
15 min in the case of pinnipeds and
porpoises
• Has not been seen within the EZ for
30 min in the case of cetaceans (except
for beluga whales which cannot not be
seen in the EZ or SZ).
Ramp up—A ‘‘ramp up’’ procedure
gradually increases airgun volume at a
specified rate. Ramp up is used at the
start of airgun operations, including
after a power down, shutdown, and after
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. During the ramp up, the
EZ for the full airgun array will be
maintained.
If the complete EZ has not been
visible for at least 30 minutes prior to
the start of operations, ramp up will not
commence unless the mitigation gun
has been operating since the power
down of seismic survey operations. This
means that it will not be permissible to
ramp up the 24-gun source from a
complete shut down 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 marine
mammal is sighted within or entering
the EZ at any time.
Speed or Course Alteration—If a
marine mammal is detected outside the
EZ and, based on its position and
relative motion, is likely to enter the EZ,
the vessel’s speed and/or direct course
may, when practical and safe, be
changed. This technique also minimizes
the effect on the seismic program. This
technique can be used in coordination
with a power down procedure. The
marine mammal activities and
movements relative to the seismic and
support vessels will be closely
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monitored to ensure that the marine
mammal does not enter the EZ. If the
mammal appears likely to enter the EZ,
further mitigation actions must be taken,
i.e., either further course alterations,
power down, or shutdown of the
airguns.
Pipe and Sheet Pile Driving Mitigation
Soon after the drill rig is positioned
on the well head, the conductor pipe
will be driven as the first stage of the
drilling operation. Two PSOs (one
operating at a time) will be stationed
aboard the rig during this two to three
day operation monitoring the EZ and
the SZ. The impact hammer operator
will be notified to shut down
hammering operations if a marine
mammal is sighted within or enters the
EZ. A soft start of the hammering will
begin at the start of each hammering
session. The soft start procedure
involves initially starting with three soft
strikes, 30 seconds apart. This delayedstrike start alerts marine mammals of
the pending hammering activity and
provides them time to vacate the area.
Monitoring will occur during all
hammering sessions.
A dock face will be constructed on the
rock causeway in Iniskin Bay. Two
PSOs will be stationed either on a vessel
or on land during the 14–21 day
operation observing an EZ of 4.6 km for
beluga whales. PSOs will implement
similar monitoring and mitigation
strategies as for the pipe installation.
For impact hammering, ‘‘soft-start’’
technique must be used at the beginning
of each day’s pipe/pile driving activities
to allow any marine mammal that may
be in the immediate area to leave before
pile driving reaches full energy.
• Clear the EZ 30 minutes prior to a
soft-start to ensure no marine mammals
are within or entering the EZ.
• Begin impact hammering soft-start
with an initial set of three strikes from
the impact hammer at 40 percent
energy, followed by a one minute
waiting period, then two subsequent 3strike sets.
• Immediately shut down all
hammers at any time a marine mammal
is detected entering or within the EZ.
• Initial hammering starts will not
begin during periods of poor visibility
(e.g., night, fog, wind).
• Any shutdown due to a marine
mammal 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.
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Water Jet Mitigation
A PSO will be present on the dive
support vessel when divers are using
the water jet. Prior to in-water use of the
water jet, the EZ around the DSV will
be established. The water jet will be
shut down if marine mammals are
observed within the EZ.
Beluga Critical Habitat Mitigation
Hilcorp must not operate noise
producing activities within 10 miles (16
km) of the mean higher high water
(MHHW) line of the Susitna Delta
(Beluga River to the Little Susitna River)
between April 15 and October 15. The
purpose of this mitigation measure is to
protect beluga whales in the designated
critical habitat in this area that is
important for beluga whale feeding and
calving during the spring and fall
months. The range of the setback
required by NMFS was designated to
protect this important habitat area and
also to create an effective buffer where
sound does not encroach on this habitat.
This seasonal exclusion is proposed to
be in effect from April 15-October 15.
Activities can occur within this area
from October 16-April 14.
Mitigation for Subsistence Uses of
Marine Mammals or Plan of
Cooperation
Regulations at 50 CFR 216.104(a)(12)
further require Incidental Take
Authorization applicants conducting
activities that take place in Arctic
waters to provide a Plan of Cooperation
or information that identifies what
measures have been taken and/or will
be taken to minimize adverse effects on
the availability of marine mammals for
subsistence purposes. A plan must
include the following:
• A statement that the applicant has
notified and provided the affected
subsistence community with a draft
plan of cooperation;
• A schedule for meeting with the
affected subsistence communities to
discuss proposed activities and to
resolve potential conflicts regarding any
aspects of either the operation or the
plan of cooperation;
• A description of what measures the
applicant has taken and/or will take to
ensure that proposed activities will not
interfere with subsistence whaling or
sealing; and
• What plans the applicant has to
continue to meet with the affected
communities, both prior to and while
conducting the activity, to resolve
conflicts and to notify the communities
of any changes in the operation.
Hilcorp Alaska has developed a
Stakeholder Engagement Plan (SEP) and
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will implement this plan throughout the
duration of the Petition. The SEP will
help coordinate activities with local
stakeholders and thus subsistence users,
minimize the risk of interfering with
subsistence hunting activities, and keep
current as to the timing and status of the
subsistence hunts. The Plan is provided
in Appendix B of Hilcorp’s application.
Presentations will be given at various
local forums. Hilcorp Alaska is working
with a contractor to update/verify our
existing stakeholder list. Meetings and
communication will be coordinated
with: commercial and sport fishing
groups/associations, various Native
fisheries and entities as it pertains to
subsistence fishing and/or hunting,
marine mammal co-management groups,
Cook Inlet Regional Citizens Advisory
Council, local landowners, government
and community organizations, and
environmental NGOs.
Based on our evaluation of the
applicant’s proposed measures, as well
as other measures considered by NMFS,
NMFS has preliminarily determined
that the proposed mitigation measures
provide the means effecting the least
practicable impact on the affected
species or stocks and their habitat,
paying particular attention to rookeries,
mating grounds, and areas of similar
significance, and on the availability of
such species or stock for subsistence
uses.
Proposed Monitoring and Reporting
In order to issue an LOA for an
activity, section 101(a)(5)(A) of the
MMPA states that NMFS must set forth,
requirements pertaining to the
monitoring and reporting of such taking.
The MMPA implementing regulations at
50 CFR 216.104 (a)(13) indicate that
requests for authorizations must include
the suggested means of accomplishing
the necessary monitoring and reporting
that will result in increased knowledge
of the species and of the level of taking
or impacts on populations of marine
mammals that are expected to be
present in the proposed action area.
Effective reporting is critical both to
compliance as well as ensuring that the
most value is obtained from the required
monitoring.
The PSOs will observe and collect
data on marine mammals in and around
the project area for 15 (well activity) or
30 minutes (seismic activity) before,
during, and for 30 minutes after all of
Hilcorp’s activities for which take has
been requested.
Protected Species Observer
Qualifications
NMFS-approved PSOs must meet the
following requirements:
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1. Independent observers (i.e., not
construction personnel) are required;
2. At least one observer must have
prior experience working as an observer;
3. Other observers may substitute
education (undergraduate degree in
biological science or related field) or
training for experience;
4. Where a team of three or more
observers are required, one observer
should be designated as lead observer or
monitoring coordinator. The lead
observer must have prior experience
working as an observer; and
5. NMFS will require submission and
approval of observer CVs.
Monitoring and reporting
requirements prescribed by NMFS
should contribute to improved
understanding of one or more of the
following:
• Occurrence of marine mammal
species or stocks in the area in which
take is anticipated (e.g., presence,
abundance, distribution, density);
• Nature, scope, or context of likely
marine mammal exposure to potential
stressors/impacts (individual or
cumulative, acute or chronic), through
better understanding of: (1) Action or
environment (e.g., source
characterization, propagation, ambient
noise); (2) affected species (e.g., life
history, dive patterns); (3) co-occurrence
of marine mammal species with the
action; or (4) biological or behavioral
context of exposure (e.g., age, calving or
feeding areas);
• Individual marine mammal
responses (behavioral or physiological)
to acoustic stressors (acute, chronic, or
cumulative), other stressors, or
cumulative impacts from multiple
stressors;
• How anticipated responses to
stressors impact either: (1) Long-term
fitness and survival of individual
marine mammals; or (2) populations,
species, or stocks;
• Effects on marine mammal habitat
(e.g., marine mammal prey species,
acoustic habitat, or other important
physical components of marine
mammal habitat); and
• Mitigation and monitoring
effectiveness.
Proposed Monitoring Measures
Sound Source Verification—When
site-specific measurements are not
available for noise sources of concern
for acoustic exposure, NMFS often
requires a sound source verification
(SSV) to characterize the sound levels,
propagation, and to verify the
monitoring zones (EZ and SZ). Hilcorp
Alaska plans to perform an SSV for the
3D seismic survey and sub-bottom
profiler in lower Cook Inlet. Hilcorp
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Alaska will work with NMFS to
determine if an SSV is needed for other
activities occurring in the action area.
Hilcorp will implement a robust
monitoring and mitigation program for
marine mammals using NMFS-approved
PSOs for Petition activities. Much of the
activities will use vessel-based PSOs,
but land- or platform-based PSOs may
also be used to augment project-specific
activities. Marine mammal monitoring
and mitigation methods have been
designed to meet the requirements and
objectives which will be specified in the
Incidental Take Regulations
promulgated by NMFS. Some details of
the monitoring and mitigation program
may change upon receipt of the
individual LOAs issued by NMFS each
year.
The main purposes of PSOs are: To
conduct visual watches for marine
mammals; to serve as the basis for
implementation of mitigation measures;
to document numbers of marine
mammals present; to record any
reactions of marine mammals to
Hilcorp’s activities; and, to identify
whether there was any possible effect on
accessibility of marine mammals to
subsistence hunters in Cook Inlet. These
observations will provide the real-time
data needed to implement some of the
key measures.
PSOs will be on watch during all
daylight periods for project-specific
activities. Generally, work is conducted
24-hrs a day, depending on the specific
activity.
• For 2D seismic surveys, the airgun
operations will be conducted during
daylight hours.
• For 3D seismic surveys, airgun
operations will continue during the
waning nighttime hours (ranges from
2230–0600 in early April to 0100–0300
in mid-May) as long as the full array or
mitigation gun is operating prior to
nightfall and mitigation airgun use
cannot be longer than three hours. Night
vision and infrared have been suggested
for low visibility conditions, but these
have not been useful in Cook Inlet or
other Alaska-based programs. Passive
acoustic monitoring has also been used
in Cook Inlet and is typically required
for seismic surveys but has not shown
to be an effective solution in Cook
Inlet’s specific environmental
conditions. A further discussion of
previous passive acoustic monitoring
efforts by several entities in Cook Inlet
is provided in Section 13 of Hilcorp’s
application.
• For the sub-bottom profiler,
operations will generally be conducted
during daylight hours but may continue
into the low visibility period as long as
the profiler is operating prior to
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nightfall. Sub-bottom profiler operations
may not begin under low visibility
conditions.
• For pipe driving, VSP, and sheet
pile driving, operations will generally
be conducted during daylight hours.
• Water jet and hydraulic grinder are
operated over a 24-hour period as they
are limited to low tide conditions.
Activities will not start during nighttime
but will continue if already started.
Pre-Activity Monitoring—The
exclusion zone will be monitored for 30
minutes prior to in-water construction/
demolition activities. If a marine
mammal is present within the exclusion
zone, the activity will be delayed until
the animal(s) leave the exclusion zone.
Activity will resume only after the PSO
has determined that, through sighting or
by waiting (15 minutes for pinnipeds
and porpoises, 30 minutes for cetaceans)
without re-sighting, the animal(s) has
moved outside the exclusion zone. If a
marine mammal is observed within or
entering the exclusion zone, the PSO
who sighted that animal will notify all
other PSOs and Hilcorp of its presence.
Post-Activity Monitoring—Monitoring
of all zones will continue for 30 minutes
following the completion of the activity.
For all activities, the PSOs will watch
for marine mammals from the best
available vantage point on the vessel or
station. Ideally this vantage point is an
elevated stable platform from which the
PSO has an unobstructed 360° view of
the water. The PSOs will scan
systematically with the naked eye and
with binoculars. When a mammal
sighting is made, the following
information about the sighting will be
carefully and accurately recorded:
• Species, group size, age/size/sex
categories (if determinable), behavior
when first sighted and after initial
sighting, heading (if consistent), bearing
and distance from the PSO, apparent
reaction to activities (e.g., none,
avoidance, approach, paralleling),
closest point of approach, and
behavioral pace.
• Time, location, speed, activity of
the vessel, sea state, ice cover, visibility,
and sun glare.
• The positions of other vessel(s) in
the vicinity of the PSO location.
• The vessel’s position, speed, water
depth, sea state, ice cover, visibility, and
sun glare will also be recorded at the
start and end of each observation watch,
every 30 minutes during a watch, and
whenever there is a change in any of
those variables.
An electronic database or paper form
will be used to record and collate data
obtained from visual observations.
The results of the PSO monitoring,
including estimates of exposure to key
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sound levels, will be presented in
weekly, monthly, and 90-day reports.
Reporting will address the requirements
established by NMFS in the LOAs. The
technical report(s) will include the list
below.
• Summaries of monitoring effort:
Total hours, total distances, and
distribution of marine mammals
throughout the study period compared
to sea state, and other factors affecting
visibility and detectability of marine
mammals;
• Analyses of the effects of various
factors influencing detectability of
marine mammals: sea state, number of
observers, and fog/glare;
• Species composition, occurrence,
and distribution of marine mammal
sightings including date, water depth,
numbers, age/size/gender categories
(when discernable), group sizes, and ice
cover; and
• Analyses of the effects of seismic
program:
Æ Sighting rates of marine mammals
during periods with and without project
activities (and other variables that could
affect detectability);
Æ Initial sighting distances versus
project activity;
Æ Closest point of approach versus
project activity;
Æ Observed behaviors and types of
movements versus project activity;
Æ Numbers of sightings/individuals
seen versus project activity;
Æ Distribution around the vessels
versus project activity;
Æ Summary of implemented
mitigation measures; and
Æ Estimates of ‘‘take by harassment.’’
Proposed Reporting Measures
Immediate reports will be submitted
to NMFS if 30 or more belugas are
detected over the course of annual
operations in the safety and exclusion
zones during operation of sound sources
to evaluate and make necessary
adjustments to monitoring and
mitigation. If the number of detected
takes for any marine mammal species is
met or exceeded, Hilcorp will
immediately cease survey operations
involving the use of active sound
sources (e.g., airguns and pingers) and
notify NMFS Office of Protected
Resources (OPR).
1. Weekly Reports (during years with
seismic surveying only)—Hilcorp would
submit a weekly field report to NMFS
Headquarters as well as the Alaska
Regional Office, no later than close of
business each Thursday during the
weeks when in-water seismic survey
activities take place. The weekly field
reports would summarize species
detected (number, location, distance
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from seismic vessel, behavior), in-water
activity occurring at the time of the
sighting (discharge volume of array at
time of sighting, seismic activity at time
of sighting, visual plots of sightings, and
number of power downs and
shutdowns), behavioral reactions to inwater activities, and the number of
marine mammals exposed.
2. Monthly Reports- Monthly reports
will be submitted to NMFS for all
months during which in-water seismic
activities take place. The monthly report
will contain and summarize the
following information:
• Dates, times, locations, heading,
speed, weather, sea conditions
(including Beaufort sea state and wind
force), and associated activities during
all seismic operations and marine
mammal sightings.
• Species, number, location, distance
from the vessel, and behavior of any
sighted marine mammals, as well as
associated seismic activity (number of
power-downs and shutdowns), observed
throughout all monitoring activities.
• An estimate of the number (by
species) exposed to the seismic activity
(based on visual observation) at received
levels greater than or equal to the NMFS
thresholds discussed above with a
discussion of any specific behaviors
those individuals exhibited.
• A description of the
implementation and effectiveness of the:
(i) Terms and conditions of the
Biological Opinion’s Incidental Take
Statement (ITS); and (ii) mitigation
measures of the LOA. For the Biological
Opinion, the report must confirm the
implementation of each Term and
Condition, as well as any conservation
recommendations, and describe their
effectiveness for minimizing the adverse
effects of the action on ESA-listed
marine mammals.
3. Annual Reports—Hilcorp must
submit an annual report within 90 days
after each activity year, starting from the
date when the LOA is issued (for the
first annual report) or from the date
when the previous annual report ended.
The annual report would include:
• Summaries of monitoring effort
(e.g., total hours, total distances, and
marine mammal distribution through
the study period, accounting for sea
state and other factors affecting
visibility and detectability of marine
mammals).
• Analyses of the effects of various
factors influencing detectability of
marine mammals (e.g., sea state, number
of observers, and fog/glare).
• Species composition, occurrence,
and distribution of marine mammal
sightings, including date, water depth,
numbers, age/size/gender categories (if
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determinable), group sizes, and ice
cover.
• Analyses of the effects of survey
operations.
• Sighting rates of marine mammals
during periods with and without
seismic survey activities (and other
variables that could affect detectability),
such as: (i) Initial sighting distances
versus survey activity state; (ii) closest
point of approach versus survey activity
state; (iii) observed behaviors and types
of movements versus survey activity
state; (iv) numbers of sightings/
individuals seen versus survey activity
state; (v) distribution around the source
vessels versus survey activity state; and
(vi) numbers of animals detected in the
harassment/safety zone.
NMFS would review the draft annual
reports. Hilcorp must then submit a
final annual report to the Chief, Permits
and Conservation Division, Office of
Protected Resources, NMFS, within 30
days after receiving comments from
NMFS on the draft annual report. If
NMFS decides that the draft annual
report needs no comments, the draft
report will be considered to be the final
report.
3. Discovery of Injured or Dead
Marine Mammals—In the event that
personnel involved in the survey
activities covered by the authorization
discover an injured or dead marine
mammal, Hilcorp must report the
incident to the Office of Protected
Resources (OPR), NMFS and to the
Alaska Regional stranding coordinator
as soon as feasible. The report must
include the following information:
• Time, date, and location (latitude/
longitude) of the first discovery (and
updated location information if known
and applicable);
• Species identification (if known) or
description of the animal(s) involved;
• Condition of the animal(s)
(including carcass condition if the
animal is dead);
• Observed behaviors of the
animal(s), if alive;
• If available, photographs or video
footage of the animal(s); and
• General circumstances under which
the animal was discovered.
Vessel Strike—In the event of a ship
strike of a marine mammal by any vessel
involved in the activities covered by the
authorization, Hilcorp must report the
incident to OPR, NMFS and to regional
stranding coordinator as soon as
feasible. The report must include the
following information:
• Time, date, and location (latitude/
longitude) of the incident;
• Species identification (if known) or
description of the animal(s) involved;
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• Vessel’s speed during and leading
up to the incident;
• Vessel’s course/heading and what
operations were being conducted (if
applicable);
• Status of all sound sources in use;
• Description of avoidance measures/
requirements that were in place at the
time of the strike and what additional
measures were taken, if any, to avoid
strike;
• Environmental conditions (e.g.,
wind speed and direction, Beaufort sea
state, cloud cover, visibility)
immediately preceding the strike;
• Estimated size and length of animal
that was struck;
• Description of the behavior of the
marine mammal immediately preceding
and following the strike;
• If available, description of the
presence and behavior of any other
marine mammals immediately
preceding the strike;
• Estimated fate of the animal (e.g.,
dead, injured but alive, injured and
moving, blood or tissue observed in the
water, status unknown, disappeared);
and
• To the extent practicable,
photographs or video footage of the
animal(s).
Actions to Minimize Additional Harm
to Live-Stranded (or Milling) Marine
Mammals—In the event of a live
stranding (or near-shore atypical
milling) event within 50 km of the
survey operations, where the NMFS
stranding network is engaged in herding
or other interventions to return animals
to the water, the Director of OPR, NMFS
(or designee) will advise the Hilcorp of
the need to implement shutdown
procedures for all active acoustic
sources operating within 50 km of the
stranding. Shutdown procedures for live
stranding or milling marine mammals
include the following:
• If at any time, the marine mammals
die or are euthanized, or if herding/
intervention efforts are stopped, the
Director of OPR, NMFS (or designee)
will advise Hilcorp that the shutdown
around the animals’ location is no
longer needed.
• Otherwise, shutdown procedures
will remain in effect until the Director
of OPR, NMFS (or designee) determines
and advises Hilcorp that all live animals
involved have left the area (either of
their own volition or following an
intervention).
• If further observations of the marine
mammals indicate the potential for restranding, additional coordination with
Hilcorp will be required to determine
what measures are necessary to
minimize that likelihood (e.g.,
extending the shutdown or moving
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operations farther away) and to
implement those measures as
appropriate.
Shutdown procedures are not related
to the investigation of the cause of the
stranding and their implementation is
not intended to imply that the specified
activity is the cause of the stranding.
Rather, shutdown procedures are
intended to protect marine mammals
exhibiting indicators of distress by
minimizing their exposure to possible
additional stressors, regardless of the
factors that contributed to the stranding.
Negligible Impact Analysis and
Determination
NMFS has defined negligible impact
as an impact resulting from the
specified activity that cannot be
reasonably expected to, and is not
reasonably likely to, adversely affect the
species or stock through effects on
annual rates of recruitment or survival
(50 CFR 216.103). A negligible impact
finding is based on the lack of likely
adverse effects on annual rates of
recruitment or survival (i.e., populationlevel effects). An estimate of the number
of takes alone is not enough information
on which to base an impact
determination. In addition to
considering estimates of the number of
marine mammals that might be ‘‘taken’’
through harassment, NMFS considers
other factors, such as the likely nature
of any responses (e.g., intensity,
duration), the context of any responses
(e.g., critical reproductive time or
location, migration), as well as effects
on habitat, and the likely effectiveness
of the mitigation. We also assess the
number, intensity, and context of
estimated takes by evaluating this
information relative to population
status. Consistent with the 1989
preamble for NMFS’s implementing
regulations (54 FR 40338; September 29,
1989), the impacts from other past and
ongoing anthropogenic activities are
incorporated into this analysis via their
impacts on the environmental baseline
(e.g., as reflected in the regulatory status
of the species, population size and
growth rate where known, ongoing
sources of human-caused mortality, or
ambient noise levels).
Given the nature of activities,
proposed mitigation and related
monitoring, no serious injuries or
mortalities are anticipated to occur as a
result of Hilcorp’s proposed oil and gas
activities in Cook Inlet, and none are
proposed to be authorized. The number
of takes that are anticipated and
proposed to be authorized are expected
to be limited mostly to short-term Level
B harassment, although some PTS may
occur. The seismic airguns and other
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sound sources do not operate
continuously over a 24-hour period.
Rather the airguns are operational for a
few hours at a time with breaks in
between, as surveys can only be
conducted during slack tides, totaling a
maximum of 12 hours a day for the most
frequently used equipment. Sources
other than airguns are likely to be used
for much shorter durations daily than
the 12 potential hours of airgun use.
Cook Inlet beluga whales, the Mexico
DPS of humpback whales, fin whales,
and the western stock of Steller sea
lions are listed as endangered under the
ESA. These stocks are also considered
depleted under the MMPA. Belugaspecific mitigation measures, such as
shutting down whenever beluga whales
are sighted by PSOs and an exclusion
zone at the Susitna River Delta months
of high beluga concentrations, aim to
minimize the effects of this activity on
the population. Zerbini et al. (2006)
estimated rates of increase of fin whales
in coastal waters south of the Alaska,
and data from Calambokidis et al. (2008)
suggest the population of humpback
whales by also be increasing. Steller sea
lion trends for the western stock are
variable throughout the region with
some decreasing and others remaining
stable or even indicating slight
increases. The other species that may be
taken by harassment during Hilcorp’s
proposed oil and gas program are not
listed as threatened or endangered
under the ESA nor as depleted under
the MMPA.
Odontocete (including Cook Inlet
beluga whales, killer whales, and harbor
porpoises) reactions to seismic energy
pulses are usually assumed to be limited
to shorter distances from the airgun(s)
than are those of mysticetes, in part
because odontocete low-frequency
hearing is assumed to be less sensitive
than that of mysticetes. When in the
Canadian Beaufort Sea in summer,
belugas appear to be fairly responsive to
seismic energy, with few being sighted
within 10–20 km (6–12 mi) of seismic
vessels during aerial surveys (Miller et
al., 2005). However, as noted above,
Cook Inlet belugas are more accustomed
to anthropogenic sound than beluga
whales in the Beaufort Sea. Therefore,
the results from the Beaufort Sea
surveys may be less applicable to
potential reactions of Cook Inlet beluga
whales. Also, due to the dispersed
distribution of beluga whales in Cook
Inlet during winter and the
concentration of beluga whales in upper
Cook Inlet from late April through early
fall (i.e., far north of the proposed
seismic surveys), belugas would likely
occur in small numbers in the majority
of Hilcorp’s proposed survey area
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during the majority of Hilcorp’s annual
operational timeframe.
Taking into account the mitigation
measures that are planned, effects on
cetaceans are generally expected to be
restricted to avoidance of a limited area
around the survey operation and shortterm changes in behavior, falling within
the MMPA definition of ‘‘Level B
harassment.’’ It is possible that Level A
take of marine mammals from sound
sources such as seismic airguns may
also occur. Due to the short term
duration of activities in any given area
and the small geographic area in which
Hilcorp’s activities would be occurring
at any one time, it is unlikely that these
activities would affect reproduction or
survival of cetaceans in Cook Inlet.
Animals are not expected to
permanently abandon any area that is
surveyed, and any behaviors that are
interrupted during the activity are
expected to resume once the activity
ceases. Only a small portion of marine
mammal habitat will be affected at any
time, and other areas within Cook Inlet
will be available for necessary biological
functions including breeding, foraging,
and mating. In addition, NMFS
proposes to seasonally restrict seismic
survey operations in locations known to
be important for beluga whale feeding,
calving, or nursing. One of the primary
locations for these biological life
functions occur in the Susitna Delta
region of upper Cook Inlet. NMFS
proposes to implement a 16 km (10 mi)
seasonal exclusion from activities for
which take has been requested in this
region from April 15 to October 15
annually. The highest concentrations of
belugas are typically found in this area
from early May through September each
year. NMFS has incorporated a 2-week
buffer on each end of this seasonal use
timeframe to account for any anomalies
in distribution and marine mammal
usage.
Mitigation measures, such as
dedicated marine mammal observers,
and shutdowns or power downs when
marine mammals are seen within
defined ranges, are designed both to
further reduce short-term reactions and
minimize any effects on hearing
sensitivity. In all cases, the effects of
these activities are expected to be shortterm, with no lasting biological
consequence. Therefore, the exposure of
cetaceans to sounds produced by
Hilcorp’s proposed oil and gas activities
is not anticipated to have an effect on
annual rates of recruitment or survival
of the affected species or stocks.
Some individual pinnipeds may be
exposed to sound from the proposed
activities more than once during the
timeframe of the project. Taking into
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account the mitigation measures that are
planned, effects on pinnipeds are
generally expected to be restricted to
avoidance of a limited area around the
survey operation and short-term
changes in behavior, falling within the
MMPA definition of ‘‘Level B
harassment,’’ although some pinnipeds
may approach close enough to sound
sources undetected and incur PTS. Due
to the solitary nature of pinnipeds in
water, this is expected to be a small
number of individuals and the
calculated distances to the PTS
thresholds incorporate a relatively long
duration, making them conservative.
Animals are not expected to
permanently abandon any area that is
surveyed, and any behaviors that are
interrupted during the activity are
expected to resume once the activity
ceases. Only a small portion of pinniped
habitat will be affected at any time, and
other areas within Cook Inlet will be
available for necessary biological
functions. In addition, the areas where
the activities will take place are largely
offshore and not known to be
biologically important areas for
pinniped populations. Therefore, the
exposure of pinnipeds to sounds
produced by this phase of Hilcorps’s
proposed activity is not anticipated to
have an effect on annual rates of
recruitment or survival on those species
or stocks.
The addition of multiple source and
supply vessels, and noise due to vessel
operations associated with the activities,
would not be outside the present
experience of marine mammals in Cook
Inlet, although levels may increase
locally. Given the large number of
vessels in Cook Inlet and the apparent
habituation to vessels by Cook Inlet
beluga whales and the other marine
mammals that may occur in the area,
vessel activity and its associated noise
is not expected to have effects that
could cause significant or long-term
consequences for individual marine
mammals or their populations.
Potential impacts to marine mammal
habitat were discussed previously in
this document (see the ‘‘Anticipated
Effects on Habitat’’ section). Although
some disturbance is possible to food
sources of marine mammals, the
impacts are anticipated to be minor
enough as to not affect annual rates of
recruitment or survival of marine
mammals in the area. Based on the size
of Cook Inlet where feeding by marine
mammals occurs versus the localized
area of the marine survey activities, any
missed feeding opportunities in the
direct project area would be minor
based on the fact that other feeding
areas exist elsewhere. Additionally,
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operations will not occur in the primary
beluga feeding and calving habitat
during times of high use by those
animals. The proposed mitigation
measure of limiting activities around the
Susistna Delta would also protect beluga
whale prey and their foraging habitat.
In summary and as described above,
the following factors primarily support
our preliminary determination that the
impacts resulting from this activity are
not expected to adversely affect the
species or stock through effects on
annual rates of recruitment or survival:
• No mortality is anticipated or
authorized;
• Increased mitigation for beluga
whales, including shutdowns at any
distance and exclusion zones and
avoiding exposure during critical
foraging periods around the Susitna
Delta;
• Location of activities offshore
which minimizes effects of activity on
resident pinnipeds at haulouts,
• Concentration of seismic surveying
in the lower portions of Cook Inlet going
into open water where densities of
marine mammals are less than other
parts of the Inlet; and
• Comprehensive land, sea, and
aerial-based monitoring maximizing
marine mammal detection rates as well
as acoustic SSV to verify exposure
levels.
Based on the analysis contained
herein of the likely effects of the
specified activity on marine mammals
and their habitat, and taking into
consideration the implementation of the
proposed monitoring and mitigation
measures, NMFS preliminarily finds
that the total marine mammal take from
the proposed activity will have a
negligible impact on all affected marine
mammal species or stocks.
Small Numbers
As noted above, only small numbers
of incidental take may be authorized
under section 101(a)(5)(A) of the MMPA
for specified activities other than
military readiness activities. The MMPA
does not define small numbers and so,
in practice, NMFS compares the number
of individuals taken within a year to the
most appropriate estimation of
abundance of the relevant species or
stock in our determination of whether
an authorization is limited to small
numbers of marine mammals.
Additionally, other qualitative factors
may be considered in the analysis, such
as the temporal or spatial scale of the
activities.
As described above in Table 18, the
takes proposed to be authorized
represent less than 25 percent of any
stock of population in the year of
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maximum activity. Further, takes are
expected to be significantly lower in the
years without 3D seismic activities. For
species listed as endangered under the
ESA, takes proposed to be authorized
represent no more than nine percent of
the stock of humpback whales, ten
percent of the stock of Cook Inlet beluga
whales, and less than one percent of the
Northeastern Pacific stock of fin whales
and Western DPS of Steller sea lions.
NMFS finds that any incidental take
reasonably likely to result annually from
the effects of the proposed activities, as
proposed to be mitigated through this
rulemaking and LOA process, will be
limited to small numbers of the affected
species or stock. In addition to the
quantitative methods used to estimate
take, NMFS also considered qualitative
factors that further support the ‘‘small
numbers’’ determination, including: (1)
The seasonal distribution and habitat
use patterns of Cook Inlet beluga
whales, which suggest that for much of
the time only a small portion of the
population would be accessible to
impacts from Hilcorp’s activity, as most
animals are found in the Susitna Delta
region of Upper Cook Inlet from early
May through September; (2) other
cetacean species and Steller sea lions
are not common in the action area; (3)
the proposed mitigation requirements,
which provide spatio-temporal
limitations that avoid impacts to large
numbers of belugas feeding and calving
in the Susitna Delta and limit exposures
to sound levels associated with Level B
harassment; (4) the proposed monitoring
requirements and mitigation measures
described earlier in this document for
all marine mammal species that will
further reduce impacts and the amount
of takes; and (5) monitoring results from
previous activities that indicated low
numbers of beluga whale sightings
within the Level B disturbance
exclusion zone and low levels of Level
B harassment takes of other marine
mammals. Additionally, the rationale
provided in the Estimated Take section
above, estimates that the number of
individual harbor seals like to be
exposed to noise that may cause
harassment is significantly less than the
number of calculated exposure due to
the resident nature of harbor seals,
offshore locations of the sound sources,
and likelihood of harbor seals to be
hauled out on land at the time sound
sources are deployed.
Based on the analysis contained
herein of the proposed activity
(including the proposed mitigation and
monitoring measures) and the
anticipated take of marine mammals,
NMFS preliminarily finds that small
numbers of marine mammals will be
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taken relative to the population size of
the affected species or stocks.
Unmitigable Adverse Impact Analysis
and Determination
In order to issue an ITA, NMFS must
find that the specified activity will not
have an ‘‘unmitigable adverse impact’’
on the subsistence uses of the affected
marine mammal species or stocks by
Alaskan Natives. NMFS has defined
‘‘unmitigable adverse impact’’ in 50 CFR
216.103 as an impact resulting from the
specified activity: (1) That is likely to
reduce the availability of the species to
a level insufficient for a harvest to meet
subsistence needs by: (i) Causing the
marine mammals to abandon or avoid
hunting areas; (ii) Directly displacing
subsistence users; or (iii) placing
physical barriers between the marine
mammals and the subsistence hunters;
and (2) that cannot be sufficiently
mitigated by other measures to increase
the availability of marine mammals to
allow subsistence needs to be met.
The project is unlikely to affect beluga
whale harvests because no beluga
harvest will take place in 2019, nor is
one likely to occur in the other years
that would be covered by the 5-year
regulations and associated LOAs.
Additionally, the proposed action area
is not an important native subsistence
site for other subsistence species of
marine mammals. Also, because of the
relatively small number of marine
mammals harvested in Cook Inlet, the
number affected by the proposed action
is expected to be extremely low.
Therefore, because the proposed action
would result in only temporary
disturbances, the proposed action
would not impact the availability of
these other marine mammal species for
subsistence uses.
The timing and location of
subsistence harvest of Cook Inlet harbor
seals may coincide with Hilcorp’s
project but, because this subsistence
hunt is conducted opportunistically and
at such a low level (NMFS, 2013c),
Hilcorp’s program is not expected to
have an impact on the subsistence use
of harbor seals.
NMFS anticipates that any effects
from Hilcorp’s proposed activities on
marine mammals, especially harbor
seals and Cook Inlet beluga whales,
which are or have been taken for
subsistence uses, would be short-term,
site specific, and limited to
inconsequential changes in behavior
and mild stress responses. NMFS does
not anticipate that the authorized taking
of affected species or stocks will reduce
the availability of the species to a level
insufficient for a harvest to meet
subsistence needs by: (1) Causing the
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marine mammals to abandon or avoid
hunting areas; (2) directly displacing
subsistence users; or (3) placing
physical barriers between the marine
mammals and the subsistence hunters.
And any such potential reductions
could be sufficiently mitigated by other
measures to increase the availability of
marine mammals to allow subsistence
needs to be met. Based on the
description of the specified activity, the
measures described to minimize adverse
effects on the availability of marine
mammals for subsistence purposes, and
the proposed mitigation and monitoring
measures, NMFS has preliminarily
determined that there will not be an
unmitigable adverse impact on
subsistence uses from Hilcorp’s
proposed activities.
Adaptive Management
The regulations governing the take of
marine mammals incidental to Hilcorp’s
proposed oil and gas activities would
contain an adaptive management
component.
The reporting requirements associated
with this proposed rule are designed to
provide NMFS with monitoring data
from the previous year to allow
consideration of whether any changes
are appropriate. The use of adaptive
management allows NMFS to consider
new information from different sources
to determine (with input from Hilcorp
regarding practicability) on an annual
basis if mitigation or monitoring
measures should be modified (including
additions or deletions). Mitigation or
monitoring measures could be modified
if new data suggests that such
modifications would have a reasonable
likelihood more effectively achieving
the goals of the mitigation and
monitoring and if the measures are
practicable.
The following are some of the
possible sources of applicable data to be
considered through the adaptive
management process: (1) Results from
monitoring reports, as required by
MMPA authorizations; (2) Results from
general marine mammal and sound
research; and (3) any information which
reveals that marine mammals may have
been taken in a manner, extent, or
number not authorized by these
regulations or subsequent LOAs.
Endangered Species Act (ESA)
Section 7(a)(2) of the Endangered
Species Act of 1973 (ESA: 16 U.S.C.
1531 et seq.) requires that each Federal
agency insure that any action it
authorizes, funds, or carries out is not
likely to jeopardize the continued
existence of any endangered or
threatened species or result in the
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destruction or adverse modification of
designated critical habitat. To ensure
ESA compliance for the issuance of
ITAs, NMFS consults internally, in this
case with the Alaska Protected
Resources Division Office, whenever we
propose to authorize take for
endangered or threatened species.
NMFS is proposing to authorize take
of Cook Inlet beluga whale,
Northeastern Pacific stock of fin whales,
Western North Pacific, Hawaii, and
Mexico DPS of humpback whales, and
western DPS of Steller sea lions, which
are listed under the ESA.
The Permit and Conservation Division
has requested initiation of section 7
consultation with the Alaska Region for
the promulgation of 5-year regulations
and the subsequent issuance of annual
LOAs. NMFS will conclude the ESA
consultation prior to reaching a
determination regarding the proposed
issuance of the authorization.
Classification
Pursuant to the procedures
established to implement Executive
Order 12866, the Office of Management
and Budget has determined that this
proposed rule is not significant.
Pursuant to section 605(b) of the
Regulatory Flexibility Act (RFA), the
Chief Counsel for Regulation of the
Department of Commerce has certified
to the Chief Counsel for Advocacy of the
Small Business Administration that this
proposed rule, if adopted, would not
have a significant economic impact on
a substantial number of small entities.
Hilcorp Alaska LLC is the only entity
that would be subject to the
requirements in these proposed
regulations. Hilcorp employs thousands
of people worldwide, and has a market
value in the billions of dollars.
Therefore, Hilcorp is not a small
governmental jurisdiction, small
organization, or small business, as
defined by the RFA. Because of this
certification, a regulatory flexibility
analysis is not required and none has
been prepared.
Notwithstanding any other provision
of law, no person is required to respond
to nor shall a person be subject to a
penalty for failure to comply with a
collection of information subject to the
requirements of the Paperwork
Reduction Act (PRA) unless that
collection of information displays a
currently valid OMB control number.
This proposed rule contains collectionof-information requirements subject to
the provisions of the PRA. These
requirements have been approved by
OMB under control number 0648–0151
and include applications for regulations,
subsequent LOAs, and reports.
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12373
List of Subjects in 50 CFR Part 217
Penalties, Reporting and
recordkeeping requirements, Seafood,
Transportation.
Dated: March 21, 2019.
Samuel D. Rauch III,
Deputy Assistant Administrator for
Regulatory Programs, National Marine
Fisheries Service.
For reasons set forth in the preamble,
50 CFR part 217 is proposed to be
amended as follows:
PART 217—REGULATIONS
GOVERNING THE TAKE OF MARINE
MAMMALS INCIDENTAL TO
SPECIFIED ACTIVITIES
1. The authority citation for part 217
continues to read as follows:
■
Authority: 16 U.S.C. 1361 et seq.
2. Add subpart Q to part 217 to read
as follows:
■
Subpart Q—Taking and Importing Marine
Mammals; Taking Marine Mammals
Incidental to Oil and Gas Activities in Cook
Inlet, Alaska
Sec.
217.160 Specified activity and specified
geographical region.
217.161 Effective dates.
217.162 Permissible methods of taking.
217.163 Prohibitions.
217.164 Mitigation requirements.
217.165 Requirements for monitoring and
reporting.
217.166 Letters of Authorization.
217.167 Renewals and modifications of
Letters of Authorization
217.168—217.169 [Reserved]
Subpart Q—Taking and Importing
Marine Mammals; Taking Marine
Mammals Incidental to Oil and Gas
Activities in Cook Inlet, Alaska
§ 217.160 Specified activity and specified
geographical region.
(a) Regulations in this subpart apply
only to Hilcorp Alaska LLC (Hilcorp)
and those persons it authorizes or funds
to conduct activities on its behalf for the
taking of marine mammals that occurs
in the area outlined in paragraph (b) of
this section and that occurs incidental
to the activities described in paragraph
(c) of this section.
(b) The taking of marine mammals by
Hilcorp may be authorized in Letters of
Authorization (LOAs) only if it occurs
within the action area defined in Cook
Inlet, Alaska.
(c) The taking of marine mammals by
Hilcorp is only authorized if it occurs
incidental to Hilcorp’s oil and gas
activities including use of seismic
airguns, sub-bottom profiler, vertical
seismic profiling, pile driving,
conductor pipe driving, and water jets.
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Effective dates and definitions.
Regulations in this subpart are
effective [EFFECTIVE DATE OF FINAL
RULE] through [DATE 5 YEARS AFTER
EFFECTIVE DATE OF FINAL RULE].
§ 217.162
Permissible methods of taking.
Under LOAs issued pursuant to
§ 216.106 of this chapter and § 217.166,
the Holder of the LOAs (hereinafter
‘‘Hilcorp’’) may incidentally, but not
intentionally, take marine mammals
within the area described in
§ 217.160(b) by Level A harassment and
Level B harassment associated with oil
and gas activities, provided the activity
is in compliance with all terms,
conditions, and requirements of the
regulations in this subpart and the
applicable LOAs.
§ 217.163
Prohibitions.
Notwithstanding takings
contemplated in § 217.162 and
authorized by LOAs issued under
§§ 216.106 of this chapter and 217.166,
no person in connection with the
activities described in § 217.160 may:
(a) Violate, or fail to comply with, the
terms, conditions, and requirements of
this subpart or a LOA issued under
§§ 216.106 of this chapter and 217.166;
(b) Take any marine mammal not
specified in such LOAs;
(c) Take any marine mammal
specified in such LOAs in any manner
other than as specified;
(d) Take a marine mammal specified
in such LOAs if NMFS determines such
taking results in more than a negligible
impact on the species or stocks of such
marine mammal; or
(e) Take a marine mammal specified
in such LOAs if NMFS determines such
taking results in an unmitigable adverse
impact on the availability of such
species or stock of marine mammal for
taking for subsistence uses.
§ 217.164
Mitigation requirements.
When conducting the activities
identified in § 217.160(c), the mitigation
measures contained in any LOAs issued
under §§ 216.106 of this chapter and
217.166 must be implemented. These
mitigation measures must include but
are not limited to:
(a) If any marine mammal species for
which take is not authorized are sighted
within or entering the relevant zones
within which they would be exposed to
sound above the 120 dB re 1 mPa (rms)
threshold for continuous (e.g., vibratory
pile-driving, drilling) sources or the 160
dB re 1 mPa (rms) threshold for nonexplosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific
sonar) sources, Hilcorp must take
appropriate action to avoid such
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exposure (e.g., by altering speed or
course or by power down or shutdown
of the sound source).
(b) If the allowable number of takes in
an LOA listed for any marine mammal
species is met or exceeded, Hilcorp
must immediately cease survey
operations involving the use of active
sound source(s), record the observation,
and notify NMFS Office of Protected
Resources.
(c) Hilcorp must notify NMFS Office
of Protected Resources at least 48 hours
prior to the start of oil and gas activities
each year.
(d) Hilcorp must conduct briefings as
necessary between vessel crews, marine
mammal monitoring team, and other
relevant personnel prior to the start of
all survey activity, and when new
personnel join the work, in order to
explain responsibilities, communication
procedures, marine mammal monitoring
protocol, and operational procedures.
(e) Establishment of monitoring and
exclusion zones. (1) For all relevant inwater construction and demolition
activity, Hilcorp must implement
shutdown zones/exclusion zones (EZs)
with radial distances as identified in
any LOA issued under §§ 216.106 of this
chapter and 217.166. If a marine
mammal is sighted within or entering
the EZ, such operations must cease.
(2) For all relevant in-water
construction and demolition activity,
Hilcorp must designate safety zones for
monitoring (SZ)with radial distances as
identified in any LOA issued under
§§ 216.106 of this chapter and 217.166
and record and report occurrence of
marine mammals within these zones.
(3) For all in-water construction and
demolition activity, Hilcorp must
implement a minimum EZ of a 10 m
radius around the source.
(f) Shutdown measures. (1) Hilcorp
must deploy protected species observers
(PSOs) and PSOs must be posted to
monitor marine mammals within the
monitoring zones during use of active
acoustic sources and pile driving in
water.
(2) Monitoring must begin 15 minutes
prior to initiation of stationary source
activity and 30 minutes prior to
initiation of mobile source activity,
occur throughout the time required to
complete the activity, and continue
through 30 minutes post-completion of
the activity. Pre-activity monitoring
must be conducted to ensure that the EZ
is clear of marine mammals, and
activities may only commence once
observers have declared the EZ clear of
marine mammals. In the event of a delay
or shutdown of activity resulting from
marine mammals in the EZ, the marine
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mammals’ behavior must be monitored
and documented.
(3) A determination that the EZ is
clear must be made during a period of
good visibility (i.e., the entire EZ must
be visible to the naked eye).
(4) If a marine mammal is observed
within or entering the EZ, Hilcorp must
halt all noise producing activities for
which take is authorized at that
location. If activity is delayed due to the
presence of a marine mammal, the
activity may not commence or resume
until either the animal has voluntarily
left and been visually confirmed outside
the EZ or the required amount of time
(15 for porpoises and pinnipeds, 30
minutes for cetaceans) have passed
without re-detection of the animal.
(5) Monitoring must be conducted by
trained observers, who must have no
other assigned tasks during monitoring
periods. Trained observers must be
placed at the best vantage point(s)
practicable to monitor for marine
mammals and implement shutdown or
delay procedures when applicable
through communication with the
equipment operator. Hilcorp must
adhere to the following additional
observer qualifications:
(i) Hilcorp must use independent,
dedicated, trained visual PSOs, meaning
that the PSOs must be employed by a
third-party observer provider, must not
have tasks other than to conduct
observational effort, collect data, and
communicate with and instruct relevant
vessel crew with regard to the presence
of protected species and mitigation
requirements (including brief alerts
regarding maritime hazards), and must
have successfully completed an
approved PSO training course
appropriate for their designated task.
(ii) Hilcorp must submit PSO resumes
for NMFS review and approval.
Resumes must be accompanied by a
relevant training course information
packet that includes the name and
qualifications (i.e., experience, training
completed, or educational background)
of the instructor(s), the course outline or
syllabus, and course reference material
as well as a document stating successful
completion of the course. NMFS is
allowed one week to approve PSOs from
the time that the necessary information
is received by NMFS, after which PSOs
meeting the minimum requirements will
automatically be considered approved.
(iii) To the maximum extent
practicable, the lead PSO must devise
the duty schedule such that experienced
PSOs are on duty with those PSOs with
appropriate training but who have not
yet gained relevant experience.
(6) Hilcorp must implement
shutdown measures if the number of
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authorized takes for any particular
species reaches the limit under the
applicable LOA and if such marine
mammals are sighted within the vicinity
of the project area and are entering the
SZ during activities.
(7) Hilcorp must implement a
shutdown if a beluga whale is seen
within or entering the EZ or SZ.
(g) Impact driving soft start. (1)
Hilcorp must implement soft start
techniques for impact pile driving.
Hilcorp must conduct an initial set of
three strikes from the impact hammer 30
seconds apart, at 40 percent energy,
followed by a 1-minute waiting period,
then two subsequent three strike sets.
(2) Soft start is required for any
impact driving, including at the
beginning of the day, after 30 minutes
of pre-activity monitoring, and at any
time following a cessation of impact pile
driving of 30 minutes or longer.
(h) Airgun ramp up. (1) Ramp up
must be used at the start of airgun
operations, including after a power
down, shutdown, and after any period
greater than 10 minutes in duration
without airgun operations.
(2) The rate of ramp up must be no
more than 6 dB per 5-minute period.
(3) Ramp up must begin with the
smallest gun in the array that is being
used for all airgun array configurations.
(4) During the ramp up, the EZ for the
full airgun array must be implemented.
(5) If the complete EZ has not been
visible for at least 30 minutes prior to
the start of operations, ramp up must
not commence.
(6) Ramp up of the airguns must not
be initiated if a marine mammal is
sighted within or entering the EZ at any
time.
(i) Airgun power down. (1) If a marine
mammal, other than a beluga whale, is
detected outside the safety zone (SZ) but
is likely to enter that zone, the airguns
may be powered down before the
animal is within the safety zone, as an
alternative to a complete shutdown.
Likewise, if a marine mammal is already
within the SZ when first detected, the
airguns may be powered down if the
PSOs determine it is a reasonable
alternative to an immediate shutdown.
If a marine mammal is already within
the EZ when first detected, the airguns
must be shut down immediately.
(2) Following a power down, airgun
activity must not resume until the
marine mammal has cleared the SZ. The
animal will be considered to have
cleared the SZ if it:
(i) Is visually observed to have left the
SZ; or
(ii) Has not been seen within the SZ
for 15 min in the case of pinnipeds and
porpoises; or
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(iii) Has not been seen within the SZ
for 30 min in the case of cetaceans.
(3) A mitigation airgun must not
operate for longer than three hours.
(j) Aircraft mitigation. (1) Hilcorp
must use aircraft daily to survey the
planned seismic survey area prior to the
start of seismic surveying. Surveying
must not begin unless the aerial flights
confirm the proposed survey area for
that day is clear of beluga whales.
(2) If beluga whales are sighted during
flights, start of seismic surveying must
be delayed until it is confirmed the area
is free of beluga whales.
(k) Beluga exclusion zone. Hilcorp
must not operate with noise producing
activity within 10 miles (16 km) of the
mean higher high water (MHHW) line of
the Susitna Delta (Beluga River to the
Little Susitna River) between April 15
and October 15.
§ 217.165 Requirements for monitoring
and reporting.
(a) Marine Mammal Monitoring
Protocols. Hilcorp must conduct
briefings between construction
supervisors and crews and the observer
team prior to the start of all pile driving
and removal activities, and when new
personnel join the work. Trained
observers must receive a general
environmental awareness briefing
conducted by Hilcorp staff. At
minimum, training must include
identification of marine mammals that
may occur in the project vicinity and
relevant mitigation and monitoring
requirements. All observers must have
no other construction-related tasks
while conducting monitoring.
(b) Activities must only commence
when the entire exclusion zone (EZ) is
visible to the naked eye and can be
adequately monitored. If conditions
(e.g., fog) prevent the visual detection of
marine mammals, activities must not be
initiated. For activities other than
seismic surveying, activity would be
halted in low visibility but vibratory
pile driving or removal would be
allowed to continue if started in good
visibility.
(c) Monitoring must begin 15 minutes
prior to initiation of stationary source
activity and 30 minutes prior to
initiation of mobile source activity,
occur throughout the time required to
complete the activity, and continue
through 30 minutes post-completion of
the activity. Pre-activity monitoring
must be conducted to ensure that the EZ
is clear of marine mammals, and
activities may only commence once
observers have declared the EZ clear of
marine mammals. In the event of a delay
or shutdown of activity resulting from
marine mammals in the EZ, the animals’
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behavior must be monitored and
documented.
(d) Reporting Measures. (1) Weekly
reports. Hilcorp must submit weekly
reports during the weeks when in-water
seismic survey activities take place. The
weekly field reports would summarize
species detected (number, location,
distance from seismic vessel, behavior),
in-water activity occurring at the time of
the sighting (discharge volume of array
at time of sighting, seismic activity at
time of sighting, visual plots of
sightings, and number of power downs
and shutdowns), behavioral reactions to
in-water activities, and the number of
marine mammals exposed.
(2) Monthly reports. Monthly reports
must be submitted to NMFS for all
months during which in-water seismic
activities take place. The monthly report
must contain and summarize the
following information: Dates, times,
locations, heading, speed, weather, sea
conditions (including Beaufort sea state
and wind force), and associated
activities during all seismic operations
and marine mammal sightings; Species,
number, location, distance from the
vessel, and behavior of any sighted
marine mammals, as well as associated
seismic activity (number of powerdowns and shutdowns), observed
throughout all monitoring activities; An
estimate of the number (by species)
exposed to the seismic activity (based
on visual observation) at received levels
greater than or equal to the NMFS
thresholds discussed above with a
discussion of any specific behaviors
those individuals exhibited; A
description of the implementation and
effectiveness of the terms and
conditions of the Biological Opinion’s
Incidental Take Statement (ITS) and
mitigation measures of the LOA.
(3) Annual Reports. (i) Hilcorp must
submit an annual report within 90 days
after each activity year, starting from the
date when the LOA is issued (for the
first annual report) or from the date
when the previous annual report ended.
(ii) Annual reports would detail the
monitoring protocol, summarize the
data recorded during monitoring, and
estimate the number of marine
mammals that may have been harassed
during the period of the report.
(iii) NMFS would provide comments
within 30 days after receiving annual
reports, and Hilcorp must address the
comments and submit revisions within
30 days after receiving NMFS
comments. If no comment is received
from the NMFS within 30 days, the
annual report will be considered
completed.
(4) Final report. (i) Hilcorp must
submit a comprehensive summary
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report to NMFS not later than 90 days
following the conclusion of marine
mammal monitoring efforts described in
this subpart.
(ii) The final report must synthesize
all data recorded during marine
mammal monitoring, and estimate the
number of marine mammals that may
have been harassed through the entire
project.
(iii) NMFS would provide comments
within 30 days after receiving this
report, and Hilcorp must address the
comments and submit revisions within
30 days after receiving NMFS
comments. If no comment is received
from the NMFS within 30 days, the final
report will be considered as final.
(5) Reporting of injured or dead
marine mammals. (i) In the event that
personnel involved in the survey
activities discover an injured or dead
marine mammal, Hilcorp must report
the incident to the Office of Protected
Resources (OPR), NMFS (301–427–
8401) and to regional stranding network
(877–925–7773) as soon as feasible. The
report must include the following
information:
(A) Time, date, and location (latitude/
longitude) of the first discovery (and
updated location information if known
and applicable);
(B) Species identification (if known)
or description of the animal(s) involved;
(C) Condition of the animal(s)
(including carcass condition if the
animal is dead);
(D) Observed behaviors of the
animal(s), if alive;
(E) If available, photographs or video
footage of the animal(s); and
(F) General circumstances under
which the animal was discovered.
(ii) In the event of a ship strike of a
marine mammal by any vessel involved
in the survey activities, Hilcorp must
report the incident to OPR, NMFS and
to regional stranding networks as soon
as feasible. The report must include the
following information:
(A) Time, date, and location (latitude/
longitude) of the incident;
(B) Species identification (if known)
or description of the animal(s) involved;
(C) Vessel’s speed during and leading
up to the incident;
(D) Vessel’s course/heading and what
operations were being conducted (if
applicable);
(E) Status of all sound sources in use;
(F) Description of avoidance
measures/requirements that were in
place at the time of the strike and what
additional measures were taken, if any,
to avoid strike;
(G) Environmental conditions (e.g.,
wind speed and direction, Beaufort sea
state, cloud cover, visibility)
immediately preceding the strike;
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(H) Estimated size and length of
animal that was struck;
(I) Description of the behavior of the
marine mammal immediately preceding
and following the strike;
(J) If available, description of the
presence and behavior of any other
marine mammals immediately
preceding the strike;
(K) Estimated fate of the animal (e.g.,
dead, injured but alive, injured and
moving, blood or tissue observed in the
water, status unknown, disappeared);
and
(L) To the extent practicable,
photographs or video footage of the
animal(s).
(iii) In the event of a live stranding (or
near-shore atypical milling) event
within 50 km of the survey operations,
where the NMFS stranding network is
engaged in herding or other
interventions to return animals to the
water, the Director of OPR, NMFS (or
designee) will advise Hilcorp of the
need to implement shutdown
procedures for all active acoustic
sources operating within 50 km of the
stranding. Shutdown procedures for live
stranding or milling marine mammals
include the following:
(A) If at any time, the marine
mammal(s) die or are euthanized, or if
herding/intervention efforts are stopped,
the Director of OPR, NMFS (or designee)
will advise Hilcorp that the shutdown
around the animals’ location is no
longer needed.
(B) Otherwise, shutdown procedures
must remain in effect until the Director
of OPR, NMFS (or designee) determines
and advises Hilcorp that all live animals
involved have left the area (either of
their own volition or following an
intervention).
(C) If further observations of the
marine mammals indicate the potential
for re-stranding, additional coordination
with Hilcorp must occur to determine
what measures are necessary to
minimize that likelihood (e.g.,
extending the shutdown or moving
operations farther away) and Hilcorp
must implement those measures as
appropriate.
(iv) If NMFS determines that the
circumstances of any marine mammal
stranding found in the vicinity of the
activity suggest investigation of the
association with survey activities is
warranted, and an investigation into the
stranding is being pursued, NMFS will
submit a written request to Hilcorp
indicating that the following initial
available information must be provided
as soon as possible, but no later than 7
business days after the request for
information.
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(A) Status of all sound source use in
the 48 hours preceding the estimated
time of stranding and within 50 km of
the discovery/notification of the
stranding by NMFS; and
(B) If available, description of the
behavior of any marine mammal(s)
observed preceding (i.e., within 48
hours and 50 km) and immediately after
the discovery of the stranding.
(C) In the event that the investigation
is still inconclusive, the investigation of
the association of the survey activities is
still warranted, and the investigation is
still being pursued, NMFS may provide
additional information requests, in
writing, regarding the nature and
location of survey operations prior to
the time period above.
§ 217.166
Letters of authorization.
(a) To incidentally take marine
mammals pursuant to these regulations,
Hilcorp must apply for and obtain
(LOAs) in accordance with § 216.106 of
this chapter for conducting the activity
identified in § 217.160(c).
(b) LOAs, unless suspended or
revoked, may be effective for a period of
time not to extend beyond the
expiration date of these regulations.
(c) An LOA application must be
submitted to the Director, Office of
Protected Resources, NMFS, by
December 31st of the year preceding the
desired start date.
(d) An LOA application must include
the following information:
(1) The date(s), duration, and the
area(s) where the activity will occur;
(2) The species and/or stock(s) of
marine mammals likely to be found
within each area;
(3) The estimated number of takes for
each marine mammal stock potentially
affected in each area for the period of
effectiveness of the Letter of
Authorization.
(4) If an application is for an LOA
renewal, it must meet the requirements
set forth in § 217.167.
(e) In the event of projected changes
to the activity or to mitigation,
monitoring, reporting (excluding
changes made pursuant to the adaptive
management provision of § 217.97(c)(1))
required by an LOA, Hilcorp must apply
for and obtain a modification of LOAs
as described in § 217.167.
(f) Each LOA must set forth:
(1) Permissible methods of incidental
taking;
(2) Means of effecting the least
practicable adverse impact (i.e.,
mitigation) on the species, their habitat,
and the availability of the species for
subsistence uses; and
(3) Requirements for monitoring and
reporting.
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(g) Issuance of the LOA(s) must be
based on a determination that the level
of taking must be consistent with the
findings made for the total taking
allowable under these regulations.
(h) If NMFS determines that the level
of taking is resulting or may result in
more than a negligible impact on the
species or stocks of such marine
mammal, the LOA may be modified or
suspended after notice and a public
comment period.
(i) Notice of issuance or denial of the
LOA(s) must be published in the
Federal Register within 30 days of a
determination.
§ 217.167 Renewals and modifications of
letters of authorization and adaptive
management.
(a) An LOA issued under §§ 216.106
of this chapter and 217.166 for the
activity identified in § 217.160(c) may
be renewed or modified upon request by
the applicant, provided that the
following are met:
(1) Notification to NMFS that the
activity described in the application
submitted under § 217.160(a) will be
undertaken and that there will not be a
substantial modification to the
described work, mitigation or
monitoring undertaken during the
upcoming or remaining LOA period;
(2) Timely receipt (by the dates
indicated) of monitoring reports, as
required under § 217.165(C)(3);
(3) A determination by the NMFS that
the mitigation, monitoring and reporting
measures required under § 217.165(c)
and the LOA issued under §§ 216.106 of
this chapter and 217.166, were
undertaken and are expected to be
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undertaken during the period of validity
of the LOA.
(b) If a request for a renewal of a
Letter of Authorization indicates that a
substantial modification, as determined
by NMFS, to the described work,
mitigation or monitoring undertaken
during the upcoming season will occur,
NMFS will provide the public a period
of 30 days for review and comment on
the request as well as the proposed
modification to the LOA. Review and
comment on renewals of Letters of
Authorization are restricted to:
(1) New cited information and data
indicating that the original
determinations made for the regulations
are in need of reconsideration; and
(2) Proposed changes to the mitigation
and monitoring requirements contained
in these regulations or in the current
Letter of Authorization.
(c) A notice of issuance or denial of
a renewal of a Letter of Authorization
will be published in the Federal
Register within 30 days of a
determination.
(d) An LOA issued under §§ 216.16 of
this chapter and 217.166 for the activity
identified in § 217.160 may be modified
by NMFS under the following
circumstances:
(1) Adaptive management. NMFS, in
response to new information and in
consultation with Hilcorp, may modify
the mitigation or monitoring measures
in subsequent LOAs if doing so creates
a reasonable likelihood of more
effectively accomplishing the goals of
mitigation and monitoring set forth in
the preamble of these regulations.
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(i) Possible sources of new data that
could contribute to the decision to
modify the mitigation or monitoring
measures include:
(A) Results from Hilcorp’s monitoring
from the previous year(s).
(B) Results from marine mammal and/
or sound research or studies.
(C) Any information that reveals
marine mammals may have been taken
in a manner, extent or number not
authorized by these regulations or
subsequent LOAs.
(ii) If, through adaptive management,
the modifications to the mitigation,
monitoring, or reporting measures are
substantial, NMFS will publish a notice
of proposed LOA in the Federal
Register and solicit public comment.
(2) NMFS will withdraw or suspend
an LOA if, after notice and opportunity
for public comment, NMFS determines
these regulations are not being
substantially complied with or that the
taking allowed is or may be having more
than a negligible impact on an affected
species or stock specified in
§ 217.162(b) or an unmitigable adverse
impact on the availability of the species
or stock for subsistence uses. The
requirement for notice and comment
will not apply if NMFS determines that
an emergency exists that poses a
significant risk to the well-being of the
species or stocks of marine mammals.
Notice would be published in the
Federal Register within 30 days of such
action.
§§ 217.168—217.169
[Reserved]
[FR Doc. 2019–05781 Filed 3–29–19; 8:45 am]
BILLING CODE 3510–22–P
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Agencies
[Federal Register Volume 84, Number 62 (Monday, April 1, 2019)]
[Proposed Rules]
[Pages 12330-12377]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-05781]
[[Page 12329]]
Vol. 84
Monday,
No. 62
April 1, 2019
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
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50 CFR Part 217
Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to Oil and Gas Activities in Cook Inlet,
Alaska; Proposed Rule
Federal Register / Vol. 84 , No. 62 / Monday, April 1, 2019 /
Proposed Rules
[[Page 12330]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[Docket No. 190214112-9112-01]
RIN 0648-BI62
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Oil and Gas Activities in Cook
Inlet, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments.
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SUMMARY: NMFS has received a request from Hilcorp Alaska LLC (Hilcorp)
for authorization to take marine mammals incidental to oil and gas
activities in Cook Inlet, Alaska, over the course of five years (2019-
2024). As required by the Marine Mammal Protection Act (MMPA), NMFS is
proposing regulations to govern that take, and requests comments on the
proposed regulations. NMFS will consider public comments prior to
making any final decision on the issuance of the requested MMPA
authorization, and agency responses will be summarized in the final
notice of our decision.
DATES: Comments and information must be received no later than May 1,
2019.
ADDRESSES: You may submit comments, identified by NOAA-NMFS-2019-0026,
by any of the following methods:
Electronic submissions: Submit all electronic public
comments via the Federal eRulemaking Portal, Go to www.regulations.gov/#!docketDetail;D=NOAA-NMFS-2019-0026, click the ``Comment Now!'' icon,
complete the required fields, and enter or attach your comments.
Mail: Submit comments to Jolie Harrison, Chief, Permits
and Conservation Division, Office of Protected Resources, National
Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD
20910-3225.
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. All comments received are a part of the
public record and will generally be posted for public viewing on
www.regulations.gov without change. All personal identifying
information (e.g., name, address, etc.), confidential business
information, or otherwise sensitive information submitted voluntarily
by the sender may be publicly accessible. Do not submit Confidential
Business Information or otherwise sensitive or protected information.
NMFS will accept anonymous comments (enter ``N/A'' in the required
fields if you wish to remain anonymous). Attachments to electronic
comments will be accepted in Microsoft Word, Excel, or Adobe PDF file
formats only.
FOR FURTHER INFORMATION CONTACT: Sara Young, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-oil-and-gas. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Purpose and Need for Regulatory Action
This proposed rule would establish a framework under the authority
of the MMPA (16 U.S.C. 1361 et seq.) to allow for the authorization of
take of marine mammals incidental to Hilcorp's oil and gas activities
in Cook Inlet, Alaska.
We received an application from Hilcorp requesting five-year
regulations and authorization to take multiple species of marine
mammals. Take would occur by Level A and Level B harassment incidental
to a variety of sources including: 2D and 3D seismic surveys, geohazard
surveys, vibratory sheet pile driving, and drilling of exploratory
wells. Please see ``Background'' below for definitions of harassment.
Legal Authority for the Proposed Action
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs
the Secretary of Commerce to allow, upon request, the incidental, but
not intentional taking of small numbers of marine mammals by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified geographical region for up to five years
if, after notice and public comment, the agency makes certain findings
and issues regulations that set forth permissible methods of taking
pursuant to that activity and other means of effecting the least
practicable adverse impact on the affected species or stocks and their
habitat (see the discussion below in the ``Proposed Mitigation''
section), as well as monitoring and reporting requirements. Section
101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR
part 216, subpart I provide the legal basis for issuing this proposed
rule containing five-year regulations, and for any subsequent letters
of authorization (LOAs). As directed by this legal authority, this
proposed rule contains mitigation, monitoring, and reporting
requirements.
Summary of Major Provisions Within the Proposed Rule
Following is a summary of the major provisions of this proposed
rule regarding Hilcorp's activities. These measures include:
Required monitoring of the ensonified areas to detect the
presence of marine mammals before beginning activities;
Shutdown of activities under certain circumstances to
minimize injury of marine mammals;
Ramp up at the beginning of seismic surveying to allow
marine mammals the opportunity to leave the area prior to beginning the
survey at full power, as well as power downs, and vessel strike
avoidance;
Ramp up of impact hammering of the drive pipe for the
conductor pipe driven from the drill rig; and
Ceasing noise producing activities within 10 miles (16 km)
of the mean higher high water (MHHW) line of the Susitna Delta (Beluga
River to the Little Susitna River) between April 15 and October 15.
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other means of effecting the least practicable adverse
impact on the
[[Page 12331]]
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of such takings are set forth.
NMFS has defined ``negligible impact'' in 50 CFR 216.103 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.
The MMPA states that the term ``take'' means to harass, hunt,
capture, kill or attempt to harass, hunt, capture, or kill any marine
mammal. Except with respect to certain activities not pertinent here,
the MMPA defines ``harassment'' as any act of pursuit, torment, or
annoyance which (i) has the potential to injure a marine mammal or
marine mammal stock in the wild (Level A harassment); or (ii) has the
potential to disturb a marine mammal or marine mammal stock in the wild
by causing disruption of behavioral patterns, including, but not
limited to, migration, breathing, nursing, breeding, feeding, or
sheltering (Level B harassment).
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
Accordingly, NMFS is preparing an Environmental Assessment (EA) to
consider the environmental impacts associated with the issuance of the
proposed rule. NMFS' EA will be made available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-oil-and-gas on the date of publication of the
proposed rule.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
rulemaking request.
Summary of Request
On April 17, 2018, NMFS received an application from Hilcorp
requesting authorization to incidentally take marine mammals, by Level
A and Level B harassment, incidental to noise exposure resulting from
oil and gas activities in Cook Inlet, Alaska, from May 2019 to April
2024. These regulations would be valid for a period of five years. On
October 8, 2018, NMFS deemed the application adequate and complete.
The use of sound sources such as those described in the application
(e.g., seismic airguns) may result in the take of marine mammals
through disruption of behavioral patterns or may cause auditory injury
of marine mammals. Therefore, incidental take authorization under the
MMPA is warranted.
Description of Proposed Activity
Overview
The scope of Hilcorp's Petition includes four stages of activity,
including exploration, development, production, and decommissioning
activities within the Applicant's area of operations in and adjacent to
Cook Inlet within the Petition's geographic area (Figures 3 and 8 in
the application). Table 1 summarizes the planned activities within the
geographic scope of this Petition, and the following text describes
these activities in more detail. This section is organized into two
primary areas within Cook Inlet: lower Cook Inlet (south of the
Forelands to Homer) and middle Cook Inlet (north of the Forelands to
Susitna/Point Possession).
Table 1--Summary of Planned Activities Included in Incidental Take Regulations (ITR) Petition
--------------------------------------------------------------------------------------------------------------------------------------------------------
Project name Cook Inlet region Year(s) planned Seasonal timing Anticipated duration Anticipated noise sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
Anchor Point 2D seismic survey.... Lower Cook Inlet, 2021 or 2022.......... April-October....... 30 days............. Marine: 1 source vessel
Anchor Point to with airgun, 1 node
Kasilof. vessel Onshore/
Intertidal: Shot holes,
tracked vehicles,
helicopters.
Outer Continental Shelf (OCS) 3D Lower Cook Inlet OCS. 2019.................. April-June.......... 45-60 days.......... 1 source vessel with
seismic survey. airguns, 2 support
vessels, 1 mitigation
vessel potentially.
OCS geohazard survey.............. Lower Cook Inlet OCS. 2019 or 2020.......... Fall 2019 or spring 30 days............. 1 vessel with chosounders
20202. and/or sub-bottom
profilers.
OCS exploratory wells............. Lower Cook Inlet OCS. 2020-2022............. April-October....... 40-60 days per well, 1 jack-up rig, drive pipe
2-4 wells per year. installation, vertical
seismic profiling, 2-3
tugs for towing rig,
support vessels,
helicopters.
Iniskin Peninsula exploration and Lower Cook Inlet, 2019-2020............. April-October....... 180 days............ Construction of causeway,
development. west side. vibratory sheet pile
driving, dredging,
vessels.
Platform & pipeline maintenance... Middle Cook Inlet.... 2019-2024............. April-October....... 180 days............ Vessels, water jets,
hydraulic grinders,
pingers, helicopters,
and/or sub-bottom
profilers.
North Cook Inlet Unit subseawell Middle Cook Inlet.... 2020.................. May................. 14 days............. 1 vessel with
geohazard survey. echosounders and/or sub-
bottom profilers.
North Cook Inlet Unit well Middle Cook Inlet.... 2020.................. May-July............ 90 days............. 1 jack-up rig, tugs
abandonment activity. towing rig, support
vessel, helicopters.
Trading Bay area geohazard survey. Middle Cook Inlet.... 2020.................. May................. 30 days............. 1 vessel with
echosounders and/or sub-
bottom profilers.
Trading Bay area exploratory wells Middle Cook Inlet.... 2020.................. May-October......... 120-150 days........ 1 jack-up rig, drive pipe
installation, vertical
seismic profiling, tugs
towing rig, support
vessel, helicopters.
Drift River terminal Lower Cook Inlet, 2023.................. April-October....... 120 days............ Vessels.
decommissioning. west side.
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 12332]]
Dates and Duration
The scope of the Petition includes exploration, development,
production, and decommissioning activities within the Applicant's area
of operations in and adjacent to Cook Inlet within the Petition's
geographic area (Figures 3 and 8 in the application) for the period of
five years beginning May 1, 2019, extending through April 30, 2024.
Specific Geographic Region
The geographic area of activity covers a total of approximately 2.7
million acres (10,926 km\2\) in Cook Inlet. It includes land and
adjacent waters in Cook Inlet including both State of Alaska and
Federal OCS waters (Figure 3 and 8 in the application). The area
extends from the north at the Susitna Delta on the west side
(61[deg]10' 48 N, 151[deg]0' 55 W) and Point Possession on the east
side (61[deg]2' 11 N, 150[deg]23' 30 W) to the south at Ursus Cove on
the west side (59[deg]26' 20 N, 153[deg]45' 5 W) and Nanwalek on the
east side (59[deg]24' 5 N, 151[deg]56' 30 W). The area is depicted in
Figures 3 amd 8 of the application.
Detailed Description of Specific Activity
Activities in Lower Cook Inlet
Based on potential future lease sales in both State and Federal
waters, operators collect two-dimensional (2D) seismic data to
determine the location of possible oil and gas prospects. Generally, 2D
survey lines are spaced farther apart than three-dimensional (3D)
surveys and are conducted in a regional pattern that provides less
detailed geological information. 2D surveys are used to cover wider
areas to map geologic structures on a regional scale. Airgun array
sizes used during 2D surveys are similar to those used during 3D
surveys.
Activities in Middle Cook Inlet
2D Seismic Survey
During the timeframe of this Petition, the region of interest for
the 2D survey is the marine, intertidal, and onshore area on the
eastern side of Cook Inlet from Anchor Point to Kasilof. The area of
interest is approximately 8 km (5 miles) offshore of the coastline. The
anticipated timing of the planned 2D survey is in the open water season
(April through October) in either 2020 or 2021. The actual survey
duration is approximately 30 days in either year.
The 2D seismic data are acquired using airguns in the marine zone,
airguns in the intertidal zone when the tide is high and drilled shot
holes in the intertidal zone when the tide is low and drilled shot
holes in the land zone. The data are recorded using an autonomous nodal
system (i.e., no cables) that are deployed in the marine, intertidal,
and land zones. The planned source lines (airgun and shot holes) are
approximately 16 km (10 mi) in length running perpendicular to the
coastline (see Figure 1 in application). The source lines are spaced
every 8 km (5 mi) in between Anchor Point and Kasilof, with
approximately 9-10 lines over the area of interest.
In the marine and high tide intertidal zones, data will be acquired
using a shallow water airgun towed behind one source vessel. Although
the precise volume of the airgun array is unknown at this time, Hilcorp
will use an airgun array similar to what has been used for surveys in
Cook Inlet by Apache (2011-2013) and SAExploration (2015): Either a
2,400 cubic inch (cui) or 1,760 cui array. A 2,400 cui airgun was
assumed for analysis in this proposed rule to be conservative in take
estimation. In addition, the source vessel will be equipped with a 440
cui shallow water source which it can deploy at high tide in the
intertidal area in less than 1.8 meter (6 feet) of water. Source lines
are oriented along the node line. A single vessel is capable of
acquiring a source line in approximately 1-2 hours (hrs). In general,
only one source line will be collected in one day to allow for all the
node deployments and retrievals, and intertidal and land zone shot
holes drilling. There are up to 10 source lines, so if all operations
run smoothly, there will only be 2 hr per day over 10 days of airgun
activity. Hilcorp anticipates the entire operation to take
approximately 30 days to complete to account for weather and equipment
contingencies.
The recording system that will be employed is an autonomous system
``nodal'' (i.e., no cables), which is expected to be made up of at
least two types of nodes; one for the land and one for the intertidal
and marine environment. For the intertidal and marine zone, this will
be a submersible multi-component system made up of three velocity
sensors and a hydrophone. These systems have the ability to record
continuous data. Inline receiver intervals for the node systems are
approximately 50 m (165 ft). For 2D seismic surveys, the nodes are
deployed along the same line as the seismic source. The deployment
length is restricted by battery duration and data storage capacity. The
marine nodes will be placed using one node vessel. The vessels required
for the 2D seismic survey include just a source vessel and a node
vessel that is conducting only passive recording.
In the marine environment, once the nodes are placed on the
seafloor, the exact position of each node is required. In very shallow
water, the node positions are either surveyed by a land surveyor when
the tide is low, or the position is accepted based on the position at
which the navigator has laid the unit. In deeper water, a hull or pole
mounted pinger to send a signal to the transponder which is attached to
each node will be used. The transponders are coded and the crew knows
which transponder goes with which node prior to the layout. The
transponders response (once pinged) is added together with several
other responses to create a suite of range and bearing between the
pinger boat and the node. Those data are then calculated to precisely
position the node. In good conditions, the nodes can be interrogated as
they are laid out. It is also common for the nodes to be pinged after
they have been laid out. Onshore and intertidal locating of source and
receivers will be accomplished with Differential Global Positioning
System/roving units (DGPS/RTK) equipped with telemetry radios which
will be linked to a base station established on the source vessel.
Survey crews will have both helicopter and light tracked vehicle
support. Offshore source and receivers will be positioned with an
integrated navigation system (INS) utilizing DGPS/RTK link to the land
base stations. The integrated navigation system will be capable of many
features that are critical to efficient safe operations. The system
will include a hazard display system that can be loaded with known
obstructions, or exclusion zones. Apache conducted a sound source
verification (SSV) for the 440 cui and 2,400 cui arrays in 2012 (Austin
and Warner 2012; 81 FR 47239). The location of the SSV was in Beshta
Bay on the western side of Cook Inlet (between Granite Point and North
Forelands). Water depths ranged from 30-70 m (98-229 ft).
For the 440 cui array, the measured levels for the broadside
direction were 217 decibel (dB) re: 1microPa ([mu]Pa) peak, 190 dB
sound exposure level (SEL), and 201 dB root mean square (rms) at a
distance of 50 m. The estimated distance to the 160 dB rms (90th
percentile) threshold assuming the empirically measured transmission
loss of 20.4 log R (Austin and Warner, 2012) was 2,500 m. Sound level
near the source were highest between 30 and 300 hertz (Hz) in the
endfire direction and between 20 Hz and 300 Hz in the broadside
direction.
For the 2,400 cui array, the measured levels for the endfire
direction were 217
[[Page 12333]]
dB peak, 185 dB SEL, and 197 dB rms at a distance of 100 m. The
estimate distance to the 160 dB rms (90th percentile) thresholds
assuming the empirically measured transmission loss of 16.9 log R was
7,770 m. Sound levels near the source were highest between 30 and 150
Hz in the endfire direction and between 50 and 200 Hz in the broadside
direction. These measured levels were used to evaluate potential Level
A (217 dB peak and 185 dB SEL at 100 m assuming 15 log transmission
loss) and Level B (7,330 m distance to 160 dB threshold) harassment
isopleths from these sound sources (see Estimated Take section).
3D Seismic Survey
During the timeframe of this Petition, Hilcorp plans to collect 3D
seismic data for approximately 45-60 days starting May 1, 2019 over 8
of the 14 OCS lease blocks in lower Cook Inlet. The 3D seismic survey
is comprised of an area of approximately 790 km\2\ (305 mi\2\) through
8 lease blocks (6357, 6405, 6406, 6407, 6455, 6456, 6457, 6458).
Hilcorp submitted an application for an Incidental Harassment
Authorization (IHA) in late 2017 for a planned survey in 2018 but
withdrew the application and now plan for the survey to take place in
2019 and cover several years of surveying and development. The survey
program is anticipated to begin May 1, 2019, and last for approximately
45-60 days through June 2019 in compliance with identified Bureau of
Ocean Energy Management (BOEM) lease stipulations. The length of the
survey will depend on weather, equipment, and marine mammal delays
(contingencies of 20 percent weather, 10 percent equipment, 10 percent
marine mammal were assumed in this analysis, or a 40 percent increase
in expected duration to account for the aforementioned delays).
Polarcus is the intended seismic contractor, and the general
seismic survey design is provided below. The 3D seismic data will be
acquired using a specially designed marine seismic vessel towing
between 8 and 12 ~2,400-m (1.5 mi) recording cables with a dual air gun
array. The survey will involve one source vessel, one support vessel,
one chase vessel, and potentially one mitigation vessel. The
anticipated seismic source to be deployed from the source vessel is a
14-airgun array with a total volume of 1,945 cui. Crew changes are
expected to occur every four to six weeks using a helicopter or support
vessel from shore bases in lower Cook Inlet. The proposed seismic
survey will be active 24 hrs per day. The array will be towed at a
speed of approximately 7.41 km/hr (4 knots), with seismic data
collected continuously. Data acquisition will occur for approximately 5
hrs, followed by a 1.5-hr period to turn and reposition the vessel for
another pass. The turn radius on the seismic vessel is approximately
3,200 m (2 mi).
The data will be shot parallel to the Cook Inlet shorelines in a
north/south direction. This operational direction will keep recording
equipment/streamers in line with Cook Inlet currents and tides and keep
the equipment away from shallow waters on the east and west sides. The
program may be modified if the survey cannot be conducted as a result
of noise conditions onsite (i.e., ambient noise). The airguns will
typically be turned off during the turns. However, depending on the
daylight hours and length of the turn, Hilcorp may use the smallest gun
in the array (45 cui) as a mitigation airgun where needed for no longer
than 3 hours. The vessel will turn into the tides to ensure the
recording cables/streamers remain in line behind the vessel.
Hilcorp plans to use an array that provides for the lowest possible
sound source to collect the target data. The proposed array is a Bolt
1900 LLXT dual gun array. The airguns will be configured as two linear
arrays or ``strings;'' each string will have 7 airguns shooting in a
``flip-flop'' configuration for a total of 14 airguns. The airguns will
range in volume from 45 to 290 cui for a total of 1,945 cui. The first
and last are spaced approximately 14 m (45.9 ft) apart and the strings
are separated by approximately 10 m (32.8 ft). The two airgun strings
will be distributed across an approximate area of 30 x 14 m (98.4 x
45.9 ft) behind the source vessel and will be towed 300-400 m (984-
1,312 ft) behind the vessel at a depth of 5 m (16.4 ft). The firing
pressure of the array is 2,000 pounds per square inch (psi). The airgun
will fire every 4.5 to 6 seconds, depending on the exact speed of the
vessel. When fired, a brief (25 milliseconds [ms] to 140 ms) pulse of
sound is emitted by all airguns nearly simultaneously. Hilcorp proposes
to use a single 45 cui airgun, the smallest airgun in the array, for
mitigation purposes.
Hilcorp intends to use 8 Sercel-type solid streamers or
functionally similar for recording the seismic data (Figure 5 in the
application). Each streamer will be approximately 2,400 m (150 mi) in
length and will be towed approximately 8-15 m (26.2-49.2 ft) or deeper
below the surface of the water. The streamers will be placed
approximately 50 m (165 ft) apart to provide a total streamer spread of
400 m (1,148 ft). Hilcorp recognizes solid streamers as best in class
for marine data acquisition because of unmatched reliability, signal to
noise ratio, low frequency content, and noise immunity.
The survey will involve one source vessel, one support vessel, one
or two chase vessels, and potentially one mitigation vessel. The source
vessel tows the airgun array and the streamers. The support vessel
provides general support for the source vessel, including supplies,
crew changes, etc. The chase vessel monitors the in-water equipment and
maintains a security perimeter around the streamers. The mitigation
vessel provides a viewing platform to augment the marine mammal
monitoring program.
The planned volume of the airgun array is 1,945 cui. Hilcorp and
their partners will be conducting detailed modeling of the array
output, but a detailed SSV has not been conducted for this array in
Cook Inlet. Therefore, for the purposes of estimating acoustic
harassment, results from previous seismic surveys in Cook Inlet by
Apache and SAExploration, particularly the 2,400 cui array, were used.
Apache conducted an SSV for the 440 cui and 2,400 cui arrays in 2012
(Austin and Warner 2012; 81 FR 47239). The location of the SSV was in
Beshta Bay on the western side of Cook Inlet (between Granite Point and
North Forelands). Water depths ranged from 30-70 m (98-229 ft). For the
2,400 cui array, the measured levels for the endfire direction were 217
dB peak, 185 dB SEL, and 197 dB rms at a distance of 100 m. The
estimate distance to the 160 dB rms (90th percentile) thresholds
assuming the empirically measured transmission loss of 16.9 log R was
7,770 m. Sound levels near the source were highest between 30 and 150
Hz in the endfire direction and between 50 and 200 Hz in the broadside
direction.
These measured levels were used to evaluate potential Level A (217
dB peak and 185 dB SEL at 100 m assuming 15 log transmission loss) and
B (7,330 m distance to 160 dB threshold) acoustic harassment of marine
mammals in this Petition.
Geohazard and Geotechnical Surveys
Upon completion of the 3D seismic survey over the lower Cook Inlet
OCS leases, Hilcorp plans to conduct a geohazard survey on site-
specific regions within the area of interest prior to conducting
exploratory drilling. The precise location is not known, as it depends
on the results of the 3D seismic survey, but the location will be
within the lease blocks. The anticipated timing of the activity is in
either the fall of 2019
[[Page 12334]]
or the spring of 2020. The actual survey duration will take
approximately 30 days.
The suite of equipment used during a typical geohazards survey
consists of single beam and multi-beam echosounders, which provide
water depths and seafloor morphology; a side scan sonar that provides
acoustic images of the seafloor; a sub-bottom profiler which provides
20 to 200 m (66 to 656 ft) sub-seafloor penetration with a 6- to 20-
centimeter (cm, 2.4-7.9-inch [in]) resolution. Magnetometers, to detect
ferrous items, may also be used. Geotechnical surveys are conducted to
collect bottom samples to obtain physical and chemical data on surface
and near sub-surface sediments. Sediment samples typically are
collected using a gravity/piston corer or grab sampler. The surveys are
conducted from a single support vessel.
The echosounders and sub-bottom profilers are generally hull-
mounted or towed behind a single vessel. The ship travels at 3-4.5
knots (5.6-8.3 km/hr). Surveys are site specific and can cover less
than one lease block in a day, but the survey extent is determined by
the number of potential drill sites in an area. BOEM guidelines at NTL-
A01 require data to be gathered on a 150 by 300 m (492 by 984 ft) grid
within 600 m (1,969 ft) of the surface location of the drill site, a
300 by 600 m (984 by 1,969 ft) grid along the wellbore path out to
1,200 m (3,937 ft) beyond the surface projection of the conductor
casing, and extending an additional 1,200 m beyond that limit with a
1,200 by 1,200 m grid out to 2,400 m (7,874 ft) from the well site.
The multibeam echosounder, single beam echosounder, and side scan
sonar operate at frequencies of greater than 200 kHz. Based on the
frequency ranges of these pieces of equipment and the hearing ranges of
the marine mammals that have the potential to occur in the action area,
the noise produced by the echosounders and side scan sonar are not
likely to result in take of marine mammals and are not considered
further in this document.
The geophysical surveys include use of a low resolution and high
resolution sub-bottom profiler. The proposed high-resolution sub-bottom
profiler operates at source level of 210 dB re 1 [mu]Pa RMS at 1 m. The
proposed system emits energy in the frequency bands of 2 to 24 kHz. The
beam width is 15 to 24 degrees. Typical pulse rate is between 3 and 10
Hz. The secondary low-resolution sub-bottom profiler will be utilized
as necessary to increase sub-bottom profile penetration. The proposed
system emits energy in the frequency bands of 1 to 4 kHz.
Exploratory Drilling
Operators will drill exploratory wells based on mapping of
subsurface structures using 2D and 3D seismic data and historical well
information. Hilcorp plans to conduct the exploratory drilling program
April to October between 2020 and 2022. The exact start date is
currently unknown and is dependent on the results of the seismic
survey, geohazard survey, and scheduling availability of the drill rig.
It is expected that each well will take approximately 40-60 days to
drill and test. Beginning in spring 2020, Hilcorp Alaska plans to
possibly drill two and as many as four exploratory wells, pending
results of the 3D seismic survey in the lower Cook Inlet OCS leases.
After testing, the wells may be plugged and abandoned.
Hilcorp Alaska proposes to conduct its exploratory drilling using a
rig similar to the Spartan 151 drill rig. The Spartan 151 is a 150 H
class independent leg, cantilevered jack-up drill rig with a drilling
depth capability of 7,620 m (25,000 ft) that can operate in maximum
water depths up to 46 m (150 ft). Depending on the rig selection and
location, the drilling rig will be towed on site using up to three
ocean- going tugs licensed to operate in Cook Inlet. Rig moves will be
conducted in a manner to minimize any potential risk regarding safety
as well as cultural or environmental impact. While under tow to the
well sites, rig operations will be monitored by Hilcorp and the
drilling contractor management. Very High Frequency (VHF) radio,
satellite, and cellular phone communication systems will be used while
the rig is under tow. Helicopter transport will also be available.
Similarly to transiting vessels, although some marine mammals could
receive sound levels in exceedance of the general acoustic threshold of
120 dB from the tugs towing the drill rig during this project, take is
unlikely to occur, primarily because of the predictable movement of
vessels and tugs. Marine mammal population density in the project area
is low (see Estimated Take section below), and those that are present
are likely habituated to the existing baseline of commercial ship
traffic. Further, there are no activity-, location-, or species-
specific circumstances or other contextual factors that would increase
concern and the likelihood of take from towing of the drill rig.
The drilling program for the well will be described in detail in an
Exploration Plan to BOEM. The Exploration Plan will present information
on the drilling mud program; casing design, formation evaluation
program; cementing programs; and other engineering information. After
rig up/rig acceptance by Hilcorp Alaska, the wells will be spudded and
drilled to bottom-hole depths of approximately 2,100 to 4,900 m (7,000
to 16,000 ft) depending on the well. It is expected that each well will
take about 40-60 days to drill and up to 10-21 days of well testing. If
two wells are drilled, it will take approximately 80-120 days to
complete the full program; if four wells are drilled, it will take
approximately 160-240 days to complete the full program.
Primary sources of rig-based acoustic energy were identified as
coming from the D399/D398 diesel engines, the PZ-10 mud pump,
ventilation fans (and associated exhaust), and electrical generators.
The source level of one of the strongest acoustic sources, the diesel
engines, was estimated to be 137 dB re 1 [micro]Pa rms at 1 m in the
141-178 Hz bandwidth. Based on this measured level, the 120 dB rms
acoustic received level isopleth would be 50 m (154 ft) away from where
the energy enters the water (jack-up leg or drill riser). Drilling and
well construction sounds are similar to vessel sounds in that they are
relatively low-level and low-frequency. Since the rig is stationary in
a location with low marine mammal density, the impact of drilling and
well construction sounds produced from the jack up rig is expected to
be lower than a typical large vessel. There is open water in all
directions from the drilling location. Any marine mammal approaching
the rig would be fully aware of its presence long before approaching or
entering the zone of influence for behavioral harassment, and we are
unaware of any specifically important habitat features (e.g.,
concentrations of prey or refuge from predators) within the rig's zone
of influence that would encourage marine mammal use and exposure to
higher levels of noise closer to the source. Given the absence of any
activity-, location-, or species-specific circumstances or other
contextual factors that would increase concern, we do not expect
routine drilling noise to result in the take of marine mammals.
When planned and permitted operations are completed, the well will
be suspended according to Bureau of Safety and Environmental
Enforcement (BSEE) regulations. The well casings will be landed in a
mudline hanger after each hole section is drilled. When the well is
abandoned, the production casing is sealed with mechanical plugging
devices and cement to prevent the movement of any reservoir fluids
[[Page 12335]]
between various strata. Each casing string will be cutoff below the
surface and sealed with a cement plug. A final shallow cement plug will
be set to approximately 3.05 m (10 ft) below the mudline. At this
point, the surface casing, conductor, and drive pipe will be cutoff and
the three cutoff casings and the mudline hanger are pulled to the deck
of the jack-up rig for final disposal. The plugging and abandonment
procedures are part of the Well Plan which is reviewed by BSEE prior to
being issued an approved Permit to Drill.
A drive pipe is a relatively short, large-diameter pipe driven into
the sediment prior to the drilling of oil wells. The drive pipe serves
to support the initial sedimentary part of the well, preventing the
looser surface layer from collapsing and obstructing the wellbore.
Drive pipes are installed using pile driving techniques. Hilcorp
proposed to drive approximately 60 m of 76.2-cm pipe at each well site
prior to drilling using a Delmar D62-22 impact hammer (or similar).
This hammer has an impact weight of 6,200 kg (13,640 lbs). The drive
pipe driving event is expected to last one to three days at each well
site, although actual pounding of the pipe will only occur
intermittently during this period. Conductors are slightly smaller
diameter pipes than the drive pipes used to transport or ``conduct''
drill cuttings to the surface. For these wells, a 50.8-cm [20-in]
conductor pipe may be drilled, not hammered, inside the drive pipe,
dependent on the integrity of surface formations.
Illingworth & Rodkin (2014) measured the hammer noise for hammering
the drive pipe operating from the rig Endeavour for Buccaneer in 2013
and report the source level at 190 dB at 55 m, with underwater levels
exceeding 160 dB rms threshold at 1.63 km (1 mi). The measured sound
levels for the pipe driving were used to evaluate potential Level A
(source level of 221dB @1m and assuming 15 logR transmission loss) and
Level B (1,630 m distance to the 160 dB threshold) acoustic harassment
of marine mammals. Conductors are slightly smaller diameter pipes than
the drive pipes used to transport or ``conduct'' drill cuttings to the
surface. For these wells, a 50.8-cm (20-in) conductor pipe may be
drilled, not hammered, inside the drive pipe, dependent on the
integrity of surface formations. There are no noise concerns associated
with the conductor pipe drilling.
Once the well is drilled, accurate follow-up seismic data may be
collected by placing a receiver at known depths in the borehole and
shooting a seismic airgun at the surface near the borehole, called
vertical seismic profiling (VSP). These data provide high-resolution
images of the geological layers penetrated by the borehole and can be
used to accurately correlate original surface seismic data. The actual
size of the airgun array is not determined until the final well depth
is known, but typical airgun array volumes are between 600 and 880 cui.
VSP typically takes less than two full days at each well site.
Illingworth & Rodkin (2014) measured a 720 cui array for Buccaneer in
2013 and report the source level at 227 dB at 1 m, with underwater
levels exceeding 160 dB rms threshold at 2.47 km (1.54 mi). The
measured sound levels for the VSP were used to evaluate potential Level
A (227 dB rms at 1 m assuming 15 logR transmission loss) and Level B
(2,470 m distance to the 160 dB threshold) harassment isopleths.
Iniskin Peninsula Exploration
Hilcorp Alaska initiated baseline exploratory data collection in
2013 for a proposed land-based oil and gas exploration and development
project on the Iniskin Peninsula of Alaska, near Chinitna Bay. The
proposed project is approximately 97 km (60 mi) west of Homer on the
west side of Cook Inlet in the Fitz Creek drainage. New project
infrastructure includes material sites, a 6.9 km (4.3 mi) long access
road, prefabricated bridges to cross four streams, an air strip, barge
landing/staging areas, fuel storage facilities, water wells and
extraction sites, an intertidal causeway, a camp/staging area, and a
drill pad. Construction is anticipated to start in 2020.
An intertidal rock causeway is proposed to be constructed adjacent
to the Fitz Creek staging area to improve the accessibility of the
barge landing during construction and drilling operations. The causeway
will extend seaward from the high tide line approximately 366 m (1,200
ft) to a landing area 46 m (150 ft) wide. A dock face will be
constructed around the rock causeway so that barges will be able to
dock along the causeway. Rock placement for the causeway is not known
to generate sound at levels expected to disturb marine mammals. The
causeway is also not proposed at a known pinniped haulout or other
biologically significant location for local marine mammals. Therefore,
rock laying for the causeway is not considered further in this
document.
The causeway will need to be 75 percent built before the
construction of the dock face will start. The dock face will be
constructed with 18-m (60-ft) tall Z-sheet piles, all installed using a
vibratory hammer. It will take approximately 14-25 days, depending on
the length of the work shift, assuming approximately 25 percent of the
day actual pile driving. The timing of pile driving will be in late
summer or early winter, after the causeway has been partially
constructed. Illingworth & Rodkin (2007) compiled measured near-source
(10 m [32.8 ft]) SPL data from vibratory pile driving for different
pile sizes ranging in diameter from 30.5 to 243.8 cm (12 to 96 in). For
this petition, the source level of the 61.0-cm (24-in) AZ steel sheet
pile from Illingworth & Rodkin (2007) was used for the sheet pile. The
measured sound levels of 160 dB rms at 10 m assuming 15 logR
transmission loss for the vibratory sheet pile driving was used to
evaluate potential Level A and B harassment isopleths.
Activities in Middle Cook Inlet
Offshore Production Platforms
Of the 17 production platforms in central Cook Inlet, 15 are owned
by Hilcorp. Hilcorp performs routine construction on their platforms,
depending on needs of the operations. Construction activities may take
place up to 24 hrs a day. In-water activities include support vessels
bringing supplies five days a week up to two trips per day between
offshore systems at Kenai (OSK) and the platform. Depending on the
needs, there may also be barges towed by tugs with equipment and
helicopters for crew and supply changes. Routine supply-related
transits from vessels and helicopters are not substantially different
from routine vessel and air traffic already occurring in Cook Inlet,
and take is not expected to occur from these activities.
Offshore Production Drilling
Hilcorp routinely conducts development drilling activities at
offshore platforms on a regular basis to meet the asset's production
needs. Development drilling activities occurs from existing platforms
within the Cook Inlet through either open well slots or existing
wellbores in existing platform legs. Drilling activities from platforms
within Cook Inlet are accomplished by using conventional drilling
equipment from a variety of rig configurations.
Some other platforms in Cook inlet have permanent drilling rigs
installed that operate under power provided by the platform power
generation systems, while others do not have drill rigs, and the use of
a mobile drill rig is required. Mobile offshore drill rigs may be
powered by the platform power generation (if compatible with the
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platform power system) or self-generate power with the use of diesel
fired generators. For the reasons outlined above for the Lower Inlet,
noise from routine drilling is not considered further in this document.
Helicopter logistics for development drilling programs operations
will include transportation for personnel and supplies. The helicopter
support will be managed through existing offshore services based at the
OSK Heliport to support rig crew changes and cargo handling. Helicopter
flights to and from the platform while drilling is occurring is
anticipated to increase (on average) by two flights per day from normal
platform operations.
Major supplies will be staged on-shore at the OSK Dock in Nikiski.
Required supplies and equipment will be moved from the staging area to
the platform in which drilling occurring by existing supply vessels
that are currently in use supporting offshore operations within Cook
Inlet. Vessel trips to and from the platform while drilling is
occurring is anticipated to increase (on average) by two trips per day
from normal platform operations. During mobile drill rig mobilization
and demobilization, one support vessel is used continuously for
approximately 30 days to facilitate moving rig equipment and materials.
Oil and Gas Pipeline Maintenance
Each year, Hilcorp Alaska must verify the structural integrity of
their platforms and pipelines located within Cook Inlet. Routine
maintenance activities include: subsea pipeline inspections,
stabilizations, and repairs; platform leg inspections and repairs; and
anode sled installations and/or replacement. In general, pipeline
stabilization and pipeline repair are anticipated to occur in
succession for a total of 6-10 weeks. However, if a pipeline
stabilization location also requires repair, the divers will repair the
pipeline at the same time they are stabilizing it. Pipeline repair
activities are only to be conducted on an as-needed basis whereas
pipeline stabilization activities will occur annually. During
underwater inspections, if the divers identify an area of the pipeline
that requires stabilization, they will place Sea-Crete bags at that
time rather than waiting until the major pipeline stabilization effort
that occurs later in the season.
Natural gas and oil pipelines located on the seafloor of the Cook
Inlet are inspected on an annual basis using ultrasonic testing (UT),
cathodic protection surveys, multi-beam sonar surveys, and sub-bottom
profilers. Deficiencies identified are corrected using pipeline
stabilization methods or USDOT-approved pipeline repair techniques. The
Applicant employs dive teams to conduct physical inspections and
evaluate cathodic protection status and thickness of subsea pipelines
on an annual basis. If required for accurate measurements, divers may
use a water jet to provide visual access to the pipeline. For
stabilization, inspection dive teams may place Sea-Crete bags beneath
the pipeline to replace any materials removed by the water jet. Results
of the inspections are recorded and significant deficiencies are noted
for repair.
Multi-beam sonar and sub-bottom profilers may also be used to
obtain images of the seabed along and immediately adjacent to all
subsea pipelines. Elements of pipeline inspections that could produce
underwater noise include: the dive support vessel, water jet, multi-
beam sonar/sub-bottom profiler and accompanying vessel.
A water jet is a zero-thrust water compressor that is used for
underwater removal of marine growth or rock debris underneath the
pipeline. The system operates through a mobile pump which draws water
from the location of the work. Water jets likely to be used in Cook
Inlet include, but are not limited to, the CaviDyne CaviBlaster[supreg]
and the Gardner Denver Liqua-Blaster. Noise generated during the use of
the water jets would be very short in duration (30 minutes or less at
any given time) and intermittent.
Hilcorp Alaska conducted underwater measurements during 13 minutes
of CaviBlaster[supreg] use in Cook Inlet in April 2017 (Austin 2017).
Received sound levels were measured up to 143 dB re 1 [micro]Pa rms at
170 m and up to 127 dB re 1 [micro]Pa rms at 1,100 m. Sounds from the
Caviblaster[supreg] were clearly detectable out to the maximum
measurement range of 1.1 km. Using the measured transmission loss of
19.5 log R (Austin 2017), the source level for the Caviblaster[supreg]
was estimated as 176 dB re 1 [mu]Pa at 1 m. The sounds were broadband
in nature, concentrated above 500 Hz with a dominant tone near 2 kHz.
Specifications for the GR 29 Underwater Hydraulic Grinder state
that the SPL at the operator's position would be 97 dB in air (Stanley
2014). There are no underwater measurements available for the grinder,
so using a rough estimate of converting sound level in dB in air to
water by adding 61.5 dB would result in an underwater level of
approximately 159 dB2. The measured sound levels for the water jet and
grinder were used to evaluate potential Level A and B acoustic
harassment isopleths.
If necessary, Hilcorp may use an underwater pipe cutter to replace
existing pipeline segments in Cook Inlet. The following tools are
likely to be used for pipeline cutting activities:
A diamond wire saw used for remote cutting underwater
structures such as pipes and I-Beams. These saws use hydraulic power
delivered by a dedicated power source. The saw usually uses a method
that pushes the spinning wire through the pipe.
A hydraulically-powered Guillotine saw which uses an
orbital cutting movement similar to traditional power saws.
Generally, sound radiated from the diamond wire cutter is not
easily discernible from the background noise during the cutting
operation. The Navy measured underwater sound levels when the diamond
saw was cutting caissons for replacing piles at an old fuel pier at
Naval Base Point Loma (Naval Base Point Loma Naval Facilities
Engineering Command Southwest 2017). They reported an average SPL for a
single cutter at 136.1-141.4 dB rms at 10 m.
Specifications for the Guillotine saw state that the SPL at the
operator's position would be 86 dB in air (Wachs 2014). There are no
underwater measurements available for the grinder, so using a rough
estimate of converting sound level in dB in air to water by adding 61.5
dB would result in an underwater level of approximately 148 dB.
Because the measured levels for use of underwater saws do not
exceed the NMFS criteria, the noise from underwater saws was not
considered further in this document. Scour spans beneath pipelines
greater than 23 m (75 ft) have the potential to cause pipeline
failures. To be conservative, scour spans of 15 m (50 ft) or greater
identified using multi-beam sonar surveys are investigated using dive
teams. Divers perform tactile inspections to confirm spans greater than
15 m (50 ft). The pipeline is stabilized along these spans with Sea-
Crete concrete bags. While in the area, the divers will also inspect
the external coating of the pipeline and take cathodic protection
readings if corrosion wrap is found to be absent. Elements of pipeline
stabilization that could produce underwater noise include: Dive support
vessel and water jet.
Significant pipeline deficiencies identified during pipeline
inspections are repaired as soon as practicable using methods
including, but not limited to, USDOT-approved clamps and/or fiber glass
wraps, bolt/flange replacements,
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and manifold replacements. In some cases, a water jet may be required
to remove sand and gravel from under or around the pipeline to allow
access for assessment and repair. The pipeline surface may also require
cleaning using a hydraulic grinder to ensure adequate repair. If
pipeline replacement is required, an underwater pipe cutter such as a
diamond wire saw or hydraulically-powered Guillotine saw may be used.
Elements of pipeline repair that could produce underwater noise
include: Dive support vessel, water jet, hydraulic grinder, and
underwater pipe cutter.
Platform Leg Inspection and Repair
Hilcorp's platforms in Cook Inlet are inspected on a routine basis.
Divers and certified rope access technicians visually inspect subsea
platform legs. These teams also identify and correct significant
structural deficiencies. Platform leg integrity and pipeline-to-
platform connections beneath the water surface are evaluated by divers
on a routine basis. Platform legs, braces, and pipeline-to-platform
connections are evaluated for cathodic protection status, structure
thickness, excessive marine growth, damage, and scour. If required,
divers may use a water jet to clean or provide access to the structure.
If necessary, remedial grinding using a hydraulic under water grinder
may be required to determine extent damage and/or to prevent further
crack propagation. All inspection results are recorded and significant
deficiencies are noted for repair. Elements of subsea platform leg
inspection and repair that could produce underwater noise include: Dive
support vessel, hydraulic grinder, water jet.
Platform leg integrity along the tidal zone is inspected on a
routine basis. Difficult-to-reach areas may be accessed using either
commercially-piloted unmanned aerial systems (UAS). Commercially-
piloted UASs may be deployed from the top-side of the platform to
obtain images of the legs. Generally, the UAS is in the air for 15-20
minutes at a time due to battery capacity, which allows for two legs
and part of the underside of the platform to be inspected. The total
time to inspect a platform is approximately 1.5 hrs of flight time. The
UAS is operated at a distance of up to 30.5 m (100 ft) from the
platform at an altitude of 9-15 m (30-50 ft) above sea level. To reduce
potential harassment of marine mammals, the area around the platform
would be inspected prior to launch of the UAS to ensure there are no
flights directly above marine mammals. As no flights will be conducted
directly over marine mammals, the effects of drone use for routine
maintenance are not considered further in this application.
Anode Sled Installation and Replacement
Galvanic and impressed current anode sleds are used to provide
cathodic protection for the pipelines and platforms in Cook Inlet.
Galvanic anode sleds do not require a power source and may be installed
along the length of the pipelines on the seafloor. Impressed current
anode sleds are located on the seafloor at each of the corners of each
platform and are powered by rectifiers located on the platform. Anodes
are placed at the seafloor using dive vessels and hand tools. If
necessary, a water jet may be used to provide access for proper
installation. Anodes and/or cables may be stabilized using Sea-Crete
bags.
Pingers
Several types of moorings are deployed in support of Hilcorp
operations; all of which require an acoustic pinger for location or
release. The pinger is deployed over the side of a vessel and a short
signal is emitted to the mooring device. The mooring device responds
with a short signal to indicate that the device is working, to indicate
range and bearing data, or to illicit a release of the unit from the
anchor. These are used for very short periods of time when needed.
The types of moorings requiring the use of pingers anticipated to
be used in the Petition period include acoustic moorings during the 3D
seismic survey (assumed 2-4 moorings), node placement for the 2D survey
(used with each node deployment), and potential current profilers
deployed each season (assumed 2-4 moorings). The total amount of time
per mooring device is less than 10 minutes during deployment and
retrieval. To avoid disturbance, the pinger would not be deployed if
marine mammals have been observed within 135 m (443 ft) of the vessel.
The short duration of the pinger deployment as well as Hilcorp's
mitigation suggests take of marine mammals from pinger use is unlikely
to occur and pingers are not considered further in this analysis.
North Cook Inlet Unit Subsea Well Plugging and Abandonment
The discovery well in the North Cook Inlet Unit was drilled over 50
years ago and is planned to be abandoned, so Hilcorp Alaska plans to
conduct a geohazard survey to locate the well and conduct plugging and
abandonment (P&A) activities for a previously drilled subsea
exploration well in 2020. The geohazard survey location is
approximately 402-804 m (\1/4\-\1/2\ mi) south of the Tyonek platform
and will take place over approximately seven days with a grid spacing
of approximately 250 m (820 ft). The suite of equipment used during a
typical geohazards survey consists of single beam and multi-beam
echosounders, which provide water depths and seafloor morphology; a
side scan sonar that provides acoustic images of the seafloor; a sub-
bottom profiler which provides 20 to 200 m (66 to 656 ft) sub-seafloor
penetration with a 6- to 20-cm (2.4-7.9-in) resolution. The
echosounders and sub-bottom profilers are generally hull-mounted or
towed behind a single vessel. The vessel travels at 3-4.5 knots (5.6-
8.3 km/hr).
After the well has been located, Hilcorp plans to conduct plugging
and abandonment activities over a 60-90 day time period in May through
July in 2020. The jack-up rig will be similar to what is described
above (the Spartan 151 drill rig, or similar). The rig will be towed
onsite using up to three ocean-going tugs. Once the jack-up rig is on
location, divers working off a boat will assist in preparing the subsea
wellhead and mudline hanger for the riser to tie the well to the jack-
up. Once the riser is placed, the BOP equipment is made up to the
riser. At this point, the well will be entered and well casings will be
plugged with mechanical devices and cement and then cutoff and pulled.
A shallow cement plug will be set in the surface casing to 3.05 m (10
ft) below the mudline hanger. The remaining well casings will be cutoff
and the mudline hanger will be recovered to the deck of the jack-up rig
for disposal. The well abandonment will be performed in accordance to
Alaska Oil and Gas Conservation Commission (AOGCC) regulations.
Trading Bay Exploratory Drilling
Hilcorp plans to conduct exploratory drilling activities in the
Trading Bay area. The specific sites of interest have not yet been
identified, but the general area is shown in Figure 3 in the
application. Hilcorp will conduct geohazard surveys over the areas of
interest to locate potential hazards prior to drilling with the same
suite of equipment as described above for exploratory drilling in the
lower Inlet. The survey is expected to take place over 30-60 days in
2019 from a single vessel.
The exploratory drilling and well completion activities will take
place in site-specific areas based on the geohazard survey. Hilcorp
plans to drill 1-2 exploratory wells in this area in the
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open water season of 2020 with the same equipment and methods as
described above for lower Inlet exploratory drilling. The noise of
routine drilling is not considered further as explained in the
description of activities in the Lower Inlet. However, drive pipe
installation and vertical seismic profiling will be considered further.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Eleven species of marine mammal have the potential to occur in the
action area during the five year period of activities proposed by
Hilcorp. These species are described in further detail below.
Fin Whales
For management purposes, three stocks of fin whales are currently
recognized in U.S. Pacific waters: Alaska (Northeast Pacific),
California/Washington/Oregon, and Hawaii. Recent analyses provide
evidence that the population structure should be reviewed and possibly
updated. However, substantially new data on the stock structure is
lacking (Muto et al. 2017). Fin whales, including the Northeastern
Pacific stock, are listed as endangered under the ESA.
Mizroch et al. (2009) provided a comprehensive summary of fin whale
sightings data, including whaling catch data and determined there could
be at least six populations of fin whales. Evidence suggests two
populations are migratory (eastern and western North Pacific) and two
to four more are year-round residents in peripheral seas such as the
Gulf of California, East China Sea, Sanriku-Hokkaido, and possibly the
Sea of Japan. The two migratory stocks are likely mingling in the
Bering Sea in July and August. Moore et al. (1998, 2006), Watkins et
al. (2000), and Stafford et al. (2007) documented high rates of calling
along the Alaska coast beginning in August/September and lasting
through February. Fin whales are regularly observed in the Gulf of
Alaska during the summer months, even though calls are seldom detected
during this period (Stafford et al. 2007). Instruments moored in the
southeast Bering Sea detected calls over the course of a year and found
peaks from September to November as well as in February and March
(Stafford et al. 2010). Delarue et al. (2013) detected calls in the
northeastern Chukchi Sea from instruments moored from July through
October from 2007 through 2010.
Fin whales are found seasonally in the Gulf of Alaska, Bering Sea,
and as far north as the northern Chukchi Sea (Muto et al. 2017).
Surveys conducted in coastal waters of the Aleutians and the Alaska
Peninsula found that fin whales occurred primarily from the Kenai
Peninsula to the Shumagin Islands and were abundant near the Semidi
Islands and Kodiak Island (Zerbini et al. 2006). An opportunistic
survey conducted on the shelf of the Gulf of Alaska found fin whales
concentrated west of Kodiak Island in Shelikof Strait, and in the
southern Cook Inlet region. Smaller numbers were also observed over the
shelf east of Kodiak to Prince William Sound (AFSC, 2003). In the
northeastern Chukchi Sea, visual sightings and acoustic detections have
been increasing, which suggests the stock may be re-occupying habitat
used prior to large-scale commercial whaling (Muto et al. 2017). Most
of these areas are feeding habitat for fin whales. Fin whales are
rarely observed in Cook Inlet, and most sightings occur near the
entrance of the inlet. During the NMFS aerial surveys in Cook Inlet
from 2000-2016, 10 sightings of 26 estimated individual fin whales in
lower Cook Inlet were observed (Shelden et al. 2013, 2015, 2016).
Humpback Whales
Currently, three populations of humpback whales are recognized in
the North Pacific, migrating between their respective summer/fall
feeding areas and winter/spring calving and mating areas as follows
(Baker et al. 1998; Calambokidis et al. 1997). Although there is
considerable distributional overlap in the humpback whale stocks that
use Alaska, the whales seasonally found in lower Cook Inlet are
probably of the Central North Pacific stock (Muto et al. 2017). Listed
as endangered under the ESA, this stock has recently been estimated at
7,890 animals (Muto et al. 2017). The Central North Pacific stock
winters in Hawaii and summers from British Columbia to the Aleutian
Islands (Calambokidis et al. 1997), including Cook Inlet.
Humpback whales in the high latitudes of the North Pacific Ocean
are seasonal migrants that feed on euphausiids and small schooling
fishes (Muto et al. 2017). During the spring, these animals migrate
north and spend the summer feeding in the prey-rich sub-polar waters of
southern Alaska, British Columbia, and the southern Chukchi Sea.
Individuals from the Western North Pacific (endangered), Hawaii (not
listed under the ESA), and the Mexico (threatened) DPSs migrate to
areas near and potentially in the Petition region. However, most of the
individuals that migrate to the Cook Inlet area are likely from the
Hawaii DPS and not the Western North Pacific or Mexico DPSs (NMFS
2017).
In the summer, humpback whales are regularly present and feeding in
the Cook Inlet region, including Shelikof Strait, Kodiak Island bays,
and the Barren Islands, in addition to Gulf of Alaska regions adjacent
to the southeast side of Kodiak Island (especially Albatross Banks),
the Kenai and Alaska peninsulas, Elizabeth Island, as well as south of
the Aleutian Islands. Humpbacks also may be present in some of these
areas throughout autumn (Muto et al. 2017).
Humpback whales have been observed during marine mammal surveys
conducted in Cook Inlet. However, their presence is largely confined to
lower Cook Inlet. Recent monitoring by Hilcorp in upper Cook Inlet has
also included sightings of humpbacks near Tyonek. During
SAExploration's 2015 seismic program, three humpback whales were
observed in Cook Inlet; two near the Forelands and one in Kachemak Bay
(Kendall et al. 2015). During NMFS' Cook Inlet beluga whale aerial
surveys from 2000-2016, there were 88 sightings of 191 estimated
individual humpback whales in lower Cook Inlet (Shelden et al. 2017).
They have been regularly seen near Kachemak Bay during the summer
months (Rugh et al. 2005). There are observations of humpback whales as
far north as Anchor Point, with recent summer observations extending to
Cape Starichkof (Owl Ridge 2014). Although several humpback whale
sightings occurred mid-inlet between Iniskin Peninsula and Kachemak
Bay, most sightings occurred outside of the Petition region near
Augustine, Barren, and Elizabeth Islands (Shelden et al. 2013, 2015,
2017).
Ferguson et al. (2015) has established Biologically Important Areas
(BIAs) as part of the NOAA Cetacean Density and Distribution Mapping
Working Group (CetMap) efforts. This information supplements the
quantitative information on cetacean density, distribution, and
occurrence by: (1) Identifying areas where cetacean species or
populations are known to concentrate for specific behaviors, or be
range-limited, but for which there is not sufficient data for their
importance to be reflected in the quantitative mapping effort; and (2)
providing additional context within which to examine potential
interactions between cetaceans and human activities. A ``Feeding Area''
[[Page 12339]]
BIA for humpback whales in the Gulf of Alaska region encompasses the
waters east of Kodiak Island (the Albatross and Portlock Banks), a
target for historical commercial whalers based out of Port Hobron,
Alaska (Ferguson et al. 2015; Reeves et al. 1985; Witteveen et al.
2007). This BIA also includes waters along the southeastern side of
Shelikof Strait and in the bays along the northwestern shore of Kodiak
Island. The highest densities of humpback whales around the Kodiak
Island BIA occur from July-August (Ferguson et al. 2015).
Minke Whale
Minke whales are most abundant in the Gulf of Alaska during summer
and occupy localized feeding areas (Zerbini et al. 2006).
Concentrations of minke whales have occurred along the north coast of
Kodiak Island (and along the south coast of the Alaska Peninsula
(Zerbini et al. 2006). The current estimate for minke whales between
Kenai Fjords and the Aleutian Islands is 1,233 individuals (Zerbini et
al. 2006). During shipboard surveys conducted in 2003, three minke
whale sightings were made, all near the eastern extent of the survey
from nearshore Prince William Sound to the shelf break (NMML 2003).
Minke whales become scarce in the Gulf of Alaska in fall; most
whales are thought to leave the region by October (Consiglieri et al.
1982). Minke whales are migratory in Alaska, but recently have been
observed off Cape Starichkof and Anchor Point year-round (Muto et al.
2017). During Cook Inlet-wide aerial surveys conducted from 1993 to
2004, minke whales were encountered three times (1998, 1999, and 2006),
both times off Anchor Point 16 miles northwest of Homer (Shelden et al.
2013, 2015, 2017). A minke whale was also reported off Cape Starichkof
in 2011 (A. Holmes, pers. comm.) and 2013 (E. Fernandez and C.
Hesselbach, pers. comm.), suggesting this location is regularly used by
minke whales, including during the winter. Several minke whales were
recorded off Cape Starichkof in early summer 2013 during exploratory
drilling (Owl Ridge 2014), suggesting this location is regularly used
by minke whales year-round. During Apache's 2014 survey, a total of 2
minke whale groups (3 individuals) were observed during this time
period, one sighting to the southeast of Kalgin Island and another
sighting near Homer (Lomac-MacNair et al. 2014). SAExploration noted
one minke whale near Tuxedni Bay in 2015 (Kendall et al. 2015). This
species is unlikely to be seen in upper Cook Inlet but may be
encountered in the mid and lower Inlet.
Killer Whales
Two different stocks of killer whales inhabit the Cook Inlet region
of Alaska: the Alaska Resident Stock and the Gulf of Alaska, Aleutian
Islands, Bering Sea Transient Stock (Muto et al 2017). Seasonal and
year-round occurrence has been noted for killer whales throughout
Alaska (Braham and Dahlheim 1982), where whales have been labeled as
``resident,'' ``transient,'' and ``offshore'' type killer whales
(Dahlheim et al. 2008; Ford et al. 2000). The killer whales using Cook
Inlet are thought to be a mix of resident and transient individuals
from two different stocks: the Alaska Resident Stock, and the Gulf of
Alaska, Aleutian Islands, and Bering Sea Transient Stock (Allen and
Angliss 2015). Although recent studies have documented movements of
Alaska Resident killer whales from the Bering Sea into the Gulf of
Alaska as far north as southern Kodiak Island, none of these whales
have been photographed further north and east in the Gulf of Alaska
where regular photo-identification studies have been conducted since
1984 (Muto et al. 2017).
Killer whales are occasionally observed in lower Cook Inlet,
especially near Homer and Port Graham (Shelden et al. 2003; Rugh et al.
2005). The few whales that have been photographically identified in
lower Cook Inlet belong to resident groups more commonly found in
nearby Kenai Fjords and Prince William Sound (Shelden et al. 2003). The
availability of these prey species largely determines the likeliest
times for killer whales to be in the area. During aerial surveys
conducted between 1993 and 2004, killer whales were observed on only
three flights, all in the Kachemak and English Bay area (Rugh et al.
2005). However, anecdotal reports of killer whales feeding on belugas
in upper Cook Inlet began increasing in the 1990s, possibly in response
to declines in sea lion and harbor seal prey elsewhere (Shelden et al.
2003).
One killer whale group of two individuals was observed during the
2015 SAExploration seismic program near the North Foreland (Kendall et
al. 2015). During NMFS aerial surveys, killer whales were observed in
1994 (Kamishak Bay), 1997 (Kachemak Bay), 2001 (Port Graham), 2005
(Iniskin Bay), 2010 (Elizabeth and Augustine Islands), and 2012
(Kachemak Bay; Shelden et al. 2013). Eleven killer whale strandings
have been reported in Turnagain Arm, six in May 1991, and five in
August 1993. This species is expected to be rarely seen in upper Cook
Inlet but may be encountered in the mid and lower Inlet.
Gray Whales
Gray whales have been reported feeding near Kodiak Island, in
southeastern Alaska, and south along the Pacific Northwest (Allen and
Angliss 2013). Because most gray whales migrating through the Gulf of
Alaska region are thought to take a coastal route, BIA boundaries for
the migratory corridor in this region were defined by the extent of the
continental shelf (Ferguson et al. 2015).
Most gray whales calve and breed from late December to early
February in protected waters along the western coast of Baja
California, Mexico. In spring, the ENP stock of gray whales migrates
approximately 8,000 km (5,000 mi) to feeding grounds in the Bering and
Chukchi seas before returning to their wintering areas in the fall
(Rice and Wolman 1971). Northward migration, primarily of individuals
without calves, begins in February; some cow/calf pairs delay their
departure from the calving area until well into April (Jones and Swartz
1984).
Gray whales approach the proposed action area in late March, April,
May, and June, and leave again in November and December (Consiglieri et
al. 1982; Rice and Wolman 1971) but migrate past the mouth of Cook
Inlet to and from northern feeding grounds. Some gray whales do not
migrate completely from Baja to the Chukchi Sea but instead feed in
select coastal areas in the Pacific Northwest, including lower Cook
Inlet (Moore et al. 2007). Most of the population follows the outer
coast of the Kodiak Archipelago from the Kenai Peninsula in spring or
the Alaska Peninsula in fall (Consiglieri et al. 1982; Rice and Wolman
1971). Though most gray whales migrate past Cook Inlet, small numbers
have been noted by fishers near Kachemak Bay, and north of Anchor Point
(BOEM 2015). During the NMFS aerial surveys, gray whales were observed
in the month of June in 1994, 2000, 2001, 2005 and 2009 on the east
side of Cook Inlet near Port Graham and Elizabeth Island but also on
the west side near Kamishak Bay (Shelden et al. 2013). One gray whale
was sighted as far north at the Beluga River. Additionally, summering
gray whales were seen offshore of Cape Starichkof by marine mammal
observers monitoring Buccaneer's Cosmopolitan drilling program in 2013
(Owl Ridge 2014). During Apache's 2012 seismic program, nine gray
whales were observed in June and July (Lomac-MacNair et al. 2013).
During Apache's seismic program in 2014, one gray whale was observed
(Lomac- MacNair et al. 2014). During SAExploration's seismic survey in
2015,
[[Page 12340]]
no gray whales were observed (Kendall et al. 2015). This species is
unlikely to be seen in upper Cook Inlet but may be encountered in the
mid and lower Inlet.
Cook Inlet Beluga Whales
The Cook Inlet beluga whale DPS is a small geographically isolated
population that is separated from other beluga populations by the
Alaska Peninsula. The population is genetically distinct from other
Alaska populations suggesting the peninsula is an effective barrier to
genetic exchange (O'Corry-Crowe et al. 1997). The Cook Inlet beluga
whale population is estimated to have declined from 1,300 animals in
the 1970s (Calkins 1989) to about 340 animals in 2014 (Shelden et al.
2015). The precipitous decline documented in the mid-1990s was
attributed to unsustainable subsistence practices by Alaska Native
hunters (harvest of >50 whales per year) (Mahoney and Shelden 2000). In
2006, a moratorium to cease hunting was agreed upon to protect the
species. In April 2011, NMFS designated critical habitat for the beluga
under the ESA (76 FR 20180) as shown on Figure 13 of the application.
NMFS finalized the Conservation Plan for the Cook Inlet beluga in 2008
(NMFS 2008a). NMFS finalized the Recovery Plan for Cook Inlet beluga
whales in 2016 (NMFS 2016a).
The Cook Inlet beluga stock remains within Cook Inlet throughout
the year (Goetz et al. 2012a). Two areas, consisting of 7,809 km\2\
(3,016 mi\2\) of marine and estuarine environments considered essential
for the species' survival and recovery were designated critical
habitat. However, in recent years the range of the beluga whale has
contracted to the upper reaches of Cook Inlet because of the decline in
the population (Rugh et al. 2010). Area 1 of the Cook Inlet beluga
whale critical habitat encompasses all marine waters of Cook Inlet
north of a line connecting Point Possession (61.04[deg] N, 150.37[deg]
W) and the mouth of Three Mile Creek (61.08.55[deg] N, 151.04.40[deg]
W), including waters of the Susitna, Little Susitna, and Chickaloon
Rivers below mean higher high water (MHHW). This area provides
important habitat during ice-free months and is used intensively by
Cook Inlet beluga between April and November (NMFS 2016a).
Since 1993, NMFS has conducted annual aerial surveys in June, July
or August to document the distribution and abundance of beluga whales
in Cook Inlet. The collective survey results show that beluga whales
have been consistently found near or in river mouths along the northern
shores of upper Cook Inlet (i.e., north of East and West Foreland). In
particular, beluga whale groups are seen in the Susitna River Delta,
Knik Arm, and along the shores of Chickaloon Bay. Small groups had also
been recorded seen farther south in Kachemak Bay, Redoubt Bay (Big
River), and Trading Bay (McArthur River) prior to 1996 but very rarely
thereafter. Since the mid-1990s, most (96 to 100 percent) beluga whales
in upper Cook Inlet have been concentrated in shallow areas near river
mouths, no longer occurring in the central or southern portions of Cook
Inlet (Hobbs et al. 2008). Based on these aerial surveys, the
concentration of beluga whales in the northernmost portion of Cook
Inlet appears to be consistent from June to October (Rugh et al. 2000,
2004a, 2005, 2006, 2007).
Though Cook Inlet beluga whales can be found throughout the inlet
at any time of year, they spend the ice-free months generally in the
upper Cook Inlet, shifting into the middle and lower Inlet in winter
(Hobbs et al. 2005). In 1999, one beluga whale was tagged with a
satellite transmitter, and its movements were recorded from June
through September of that year. Since 1999, 18 beluga whales in upper
Cook Inlet have been captured and fitted with satellite tags to provide
information on their movements during late summer, fall, winter, and
spring. Using location data from satellite-tagged Cook Inlet belugas,
Ezer et al. (2013) found most tagged whales were in the lower to middle
inlet (70 to 100 percent of tagged whales) during January through
March, near the Susitna River Delta from April to July (60 to 90
percent of tagged whales) and in the Knik and Turnagain Arms from
August to December.
During the spring and summer, beluga whales are generally
concentrated near the warmer waters of river mouths where prey
availability is high and predator occurrence is low (Moore et al.
2000). Beluga whales in Cook Inlet are believed to mostly calve between
mid-May and mid-July, and concurrently breed between late spring and
early summer (NMFS 2016a), primarily in upper Cook Inlet. Movement was
correlated with the peak discharge of seven major rivers emptying into
Cook Inlet. Boat-based surveys from 2005 to the present (McGuire and
Stephens 2017), and initial results from passive acoustic monitoring
across the entire inlet (Castellote et al. 2016) also support seasonal
patterns observed with other methods. Other surveys also confirm Cook
Inlet belugas near the Kenai River during summer months (McGuire and
Stephens 2017).
During the summer and fall, beluga whales are concentrated near the
Susitna River mouth, Knik Arm, Turnagain Arm, and Chickaloon Bay
(Nemeth et al. 2007) where they feed on migrating eulachon
(Thaleichthys pacificus) and salmon (Onchorhyncus spp.) (Moore et al.
2000). Data from tagged whales (14 tags between July and March 2000
through 2003) show beluga whales use upper Cook Inlet intensively
between summer and late autumn (Hobbs et al. 2005). Critical Habitat
Area 1 reflects this summer distribution.
As late as October, beluga whales tagged with satellite
transmitters continued to use Knik Arm and Turnagain Arm and Chickaloon
Bay, but some ranged into lower Cook Inlet south to Chinitna Bay,
Tuxedni Bay, and Trading Bay (McArthur River) in the fall (Hobbs et al.
2005). Data from NMFS aerial surveys, opportunistic sighting reports,
and satellite-tagged beluga whales confirm they are more widely
dispersed throughout Cook Inlet during the winter months (November-
April), with animals found between Kalgin Island and Point Possession.
In November, beluga whales moved between Knik Arm, Turnagain Arm, and
Chickaloon Bay, similar to patterns observed in September (Hobbs et al.
2005). By December, beluga whales were distributed throughout the upper
to mid-inlet. From January into March, they moved as far south as
Kalgin Island and slightly beyond in central offshore waters. Beluga
whales also made occasional excursions into Knik Arm and Turnagain Arm
in February and March despite ice cover greater than 90 percent (Hobbs
et al. 2005).
During Apache's seismic test program in 2011 along the west coast
of Redoubt Bay, lower Cook Inlet, a total of 33 beluga whales were
sighted during the survey (Lomac-MacNair et al. 2013). During Apache's
2012 seismic program in mid-inlet, a total of 151 sightings of
approximately 1,463 estimated individual beluga whales were observed
(Lomac-MacNair et al. 2013). During SAExploration's 2015 seismic
program, a total of eight sightings of approximately 33 estimated
individual beluga whales were visually observed during this time period
and there were two acoustic detections of beluga whales (Kendall et al.
2015). Hilcorp recently reported 143 sightings of beluga whales while
conducting pipeline work near Ladd Landing in upper Cook Inlet, which
is not near the area that seismic surveys are proposed but near some
potential well sites.
Ferguson et al. (2015) delineated one ``Small'' and ``Resident''
BIA for Cook Inlet beluga whales. Small and Resident BIAs are defined
as ``areas and time within which small and resident
[[Page 12341]]
populations occupy a limited geographic extent'' (Ferguson et al.
2015). The Cook Inlet beluga whale BIA was delineated using the habitat
model results of Goetz et al. 2012 and the critical habitat boundaries
(76 FR 20180).
Harbor Porpoise
In Alaskan waters, three stocks of harbor porpoises are currently
recognized for management purposes: Southeast Alaska, Gulf of Alaska,
and Bering Sea Stocks (Muto et al. 2017). Porpoises found in Cook Inlet
belong to the Gulf of Alaska Stock which is distributed from Cape
Suckling to Unimak Pass and most recently was estimated to number
31,046 individuals (Muto et al. 2017). They are one of the three marine
mammals (the other two being belugas and harbor seals) regularly seen
throughout Cook Inlet (Nemeth et al. 2007), especially during spring
eulachon and summer salmon runs.
Harbor porpoises primarily frequent the coastal waters of the Gulf
of Alaska and Southeast Alaska (Dahlheim et al. 2000, 2008), typically
occurring in waters less than 100 m deep (Hobbs and Waite 2010). The
range of the Gulf of Alaska stock includes the entire Cook Inlet,
Shelikof Strait, and the Gulf of Alaska. Harbor porpoises have been
reported in lower Cook Inlet from Cape Douglas to the West Foreland,
Kachemak Bay, and offshore (Rugh et al. 2005a). Although they have been
frequently observed during aerial surveys in Cook Inlet (Shelden et al.
2014), most sightings are of single animals, and are concentrated at
Chinitna and Tuxedni bays on the west side of lower Cook Inlet (Rugh et
al. 2005) and in the upper inlet. The occurrence of larger numbers of
porpoise in the lower Cook Inlet may be driven by greater availability
of preferred prey and possibly less competition with beluga whales, as
belugas move into upper inlet waters to forage on Pacific salmon during
the summer months (Shelden et al. 2014).
The harbor porpoise frequently has been observed during summer
aerial surveys of Cook Inlet, with most sightings of individuals
concentrated at Chinitna and Tuxedni Bays on the west side of lower
Cook Inlet (Figure 14 of the application; Rugh et al. 2005). Mating
probably occurs from June or July to October, with peak calving in May
and June (as cited in Consiglieri et al. 1982). Small numbers of harbor
porpoises have been consistently reported in the upper Cook Inlet
between April and October, except for a recent survey that recorded
higher numbers than typical. NMFS aerial surveys have identified many
harbor porpoise sightings throughout Cook Inlet.
During Apache's 2012 seismic program, 137 sightings (190
individuals) were observed between May and August (Lomac-MacNair et al.
2013). Lomac-MacNair et al. 2014 identified 77 groups of harbor
porpoise totaling 13 individuals during Apache's 2014 seismic survey,
both from vessels and aircraft, during the month of May. During
SAExploration's 2015 seismic survey, 52 sightings (65 individuals) were
observed north of the Forelands (Kendall et al. 2015).
Recent passive acoustic research in Cook Inlet by Alaska Department
of Fish and Game (ADF&G) and the Marine Mammal Laboratory (MML) have
indicated that harbor porpoises occur more frequently than expected,
particularly in the West Foreland area in the spring (Castellote et al.
2016), although overall numbers are still unknown at this time.
Dall's Porpoise
Dall's porpoises are widely distributed throughout the North
Pacific Ocean including preferring deep offshore and shelf-slopes, and
deep oceanic waters (Muto et al. 2017). The Dall's porpoise range in
Alaska extends into the southern portion of the Petition region (Figure
14 of the application). Dall's porpoises are present year-round
throughout their entire range in the northeast including the Gulf of
Alaska, and occasionally the Cook Inlet area (Morejohn 1979). This
porpoise also has been observed in lower Cook Inlet, around Kachemak
Bay, and rarely near Anchor Point (Owl Ridge 2014; BOEM 2015).
Throughout most of the eastern North Pacific they are present
during all months of the year, although there may be seasonal onshore-
offshore movements along the west coast of the continental United
States and winter movements of populations out of areas with ice such
as Prince William Sound (Muto et al. 2017). Dall's porpoises were
observed (2 groups, 3 individuals) during Apache's 2014 seismic survey
which occurred in the summer months (Lomac-MacNair et al. 2014). Dall's
porpoises were observed during the month of June in 1997 (Iniskin Bay),
199 (Barren Island), and 2000 (Elizabeth Island, Kamishak Bay and
Barren Island) (Shelden et al. 2013). Dall's porpoises have been
observed in lower Cook Inlet, including Kachemak Bay and near Anchor
Point (Owl Ridge 2014). One Dall's porpoise was observed in August
north of Nikiski in the middle of the Inlet during SAExploration's 2015
seismic program (Kendall et al. 2015).
Harbor Seal
Harbor seals occupy a wide variety of habitats in freshwater and
saltwater in protected and exposed coastlines and range from Baja
California north along the west coasts of Washington, Oregon, and
California, British Columbia, and Southeast Alaska; west through the
Gulf of Alaska, Prince William Sound, and the Aleutian Islands; and
north in the Bering Sea to Cape Newenham and the Pribilof Islands.
Harbor seals are found throughout the entire lower Cook Inlet
coastline, hauling out on beaches, islands, mudflats, and at the mouths
of rivers where they whelp and feed (Muto et al. 2017).
The major haul out sites for harbor seals are located in lower Cook
Inlet. The presence of harbor seals in upper Cook Inlet is seasonal. In
Cook Inlet, seal use of western habitats is greater than use of the
eastern coastline (Boveng et al. 2012). NMFS has documented a strong
seasonal pattern of more coastal and restricted spatial use during the
spring and summer for breeding, pupping, and molting, and more wide-
ranging seal movements within and outside of Cook Inlet during the
winter months (Boveng et al. 2012). Large-scale patterns indicate a
portion of harbor seals captured in Cook Inlet move out of the area in
the fall, and into habitats within Shelikof Strait, Northern Kodiak
Island, and coastal habitats of the Alaska Peninsula, and are most
concentrated in Kachemak Bay, across Cook Inlet toward Iniskin and
Iliamna Bays, and south through the Kamishak Bay, Cape Douglas and
Shelikof Strait regions (Boveng et al. 2012).
A portion of the Cook Inlet seals move into the Gulf of Alaska and
Shelikof Strait during the winter months (London et al. 2012). Seals
move back into Cook Inlet as the breeding season approaches and their
spatial use is more concentrated around haul-out areas (Boveng et al.
2012; London et al. 2012). Some seals expand their use of the northern
portion of Cook Inlet. However, in general, seals that were captured
and tracked in the southern portion of Cook Inlet remained south of the
Forelands (Boveng et al. 2012). Important harbor seal haul-out areas
occur within Kamishak and Kachemak Bays and along the coast of the
Kodiak Archipelago and the Alaska Peninsula. Chinitna Bay, Clearwater
and Chinitna Creeks, Tuxedni Bay, Kamishak Bay, Oil Bay, Pomeroy and
Iniskin Islands, and Augustine Island are also important spring- summer
breeding and molting areas and known haul-outs sites (Figure
[[Page 12342]]
15 of the application). Small-scale patterns of movement within Cook
Inlet also occur (Boveng et al. 2012). Montgomery et al. (2007)
recorded over 200 haul out sites in lower Cook Inlet alone. However,
only a few dozen to a couple hundred seals seasonally occur in upper
Cook Inlet (Rugh et al. 2005), mostly at the mouth of the Susitna River
where their numbers vary in concert with the spring eulachon and summer
salmon runs (Nemeth et al. 2007; Boveng et al. 2012).
The Cook Inlet/Shelikof Stock is distributed from Anchorage into
lower Cook Inlet during summer and from lower Cook Inlet through
Shelikof Strait to Unimak Pass during winter (Boveng et al. 2012).
Large numbers concentrate at the river mouths and embayments of lower
Cook Inlet, including the Fox River mouth in Kachemak Bay, and several
haul outs have been identified on the southern end of Kalgin Island in
lower Cook Inlet (Rugh et al. 2005; Boveng et al. 2012). Montgomery et
al. (2007) recorded over 200 haul-out sites in lower Cook Inlet alone.
During Apache's 2012 seismic program, harbor seals were observed in the
project area from early May until the end of the seismic operations in
late September (Lomac-MacNair et al. 2013). Also in 2012, up to 100
harbor seals were observed hauled out at the mouths of the Theodore and
Lewis rivers during monitoring activity associated with Apache's 2012
Cook Inlet seismic program. During Apache's 2014 seismic program, 492
groups of harbor seals (613 individuals) were observed. This was the
highest sighting rate of any marine mammal observed during the summer
of 2014 (Lomac-MacNair et al. 2014). During SAExploration's 2015
seismic survey, 823 sightings (1,680 individuals) were observed north
and between the Forelands (Kendall et al. 2015).
Steller Sea Lions
The western DPS (WDPS) stock of Steller sea lions most likely
occurs in Cook Inlet (78 FR 66139). The center of abundance for the
Western DPS is considered to extend from Kenai to Kiska Island (NMFS
2008b). The WDPS of the Steller sea lion is defined as all populations
west of longitude 144[deg] W to the western end of the Aleutian
Islands. The range of the WDPS includes 38 rookeries and hundreds of
haul out sites. The Hilcorp action area only considers the WDPS stock.
The most recent comprehensive aerial photographic and land-based
surveys of WDPS Steller sea lions in Alaska were conducted during the
2014 and 2015 breeding seasons (Fritz et al. 2015).
The WDPS of Steller sea lions is currently listed as endangered
under the ESA (55 FR 49204) and designated as depleted under the MMPA.
Critical habitat was designated on August 27, 1993 (58 FR 45269) south
of the proposed project area in the Cook Inlet region (Figure 16 of the
application). The critical habitat designation for the WDPS of Steller
sea lions was determined to include a 37 km (20 nm) buffer around all
major haul outs and rookeries, and associated terrestrial, atmospheric,
and aquatic zones, plus three large offshore foraging areas (Figure 16
of the application). NMFS also designated no entry zones around
rookeries (50 CFR 223.202). Designated critical habitat is located
outside Cook Inlet at Gore Point, Elizabeth Island, Perl Island, and
Chugach Island (NMFS 2008b).
The geographic center of Steller sea lion distribution is the
Aleutian Islands and the Gulf of Alaska, although as the WDPS has
declined, rookeries in the west became progressively smaller (NMFS
2008b). Steller sea lion habitat includes terrestrial sites for
breeding and pupping (rookeries), resting (haul outs), and marine
foraging areas. Nearly all rookeries are at sites inaccessible to
terrestrial predators on remote rocks, islands, and reefs. Steller sea
lions inhabit lower Cook Inlet, especially near Shaw Island and
Elizabeth Island (Nagahut Rocks) haul out sites (Rugh et al. 2005) but
are rarely seen in upper Cook Inlet (Nemeth et al. 2007). Steller sea
lions occur in Cook Inlet but south of Anchor Point around the offshore
islands and along the west coast of the upper inlet in the bays
(Chinitna Bay, Iniskin Bay, etc.) (Rugh et al. 2005). Portions of the
southern reaches of the lower inlet are designated as critical habitat,
including a 20-nm buffer around all major haulout sites and rookeries.
Rookeries and haul out sites in lower Cook Inlet include those near the
mouth of the inlet, which are far south of the project area.
Steller sea lions feed largely on walleye pollock, salmon, and
arrowtooth flounder during the summer, and walleye pollock and Pacific
cod during the winter (Sinclair and Zeppelin 2002). Except for salmon,
none of these are found in abundance in upper Cook Inlet (Nemeth et al.
2007).
Steller sea lions can travel considerable distances (Baba et al.
2000). Steller sea lions are not known to migrate annually, but
individuals may widely disperse outside of the breeding season (late
May to early July; Jemison et al. 2013; Allen and Angliss 2014). Most
adult Steller sea lions inhabit rookeries during the breeding season
(late May to early July). Some juveniles and non-breeding adults occur
at or near rookeries during the breeding season, but most are on haul
outs. Adult males may disperse widely after the breeding season and,
during fall and winter, many sea lions increase use of haul outs,
especially terrestrial sites but also on sea ice in the Bering Sea
(NMFS 2008b).
Steller sea lions have been observed during marine mammal surveys
conducted in Cook Inlet. In 2012, during Apache's 3D Seismic surveys,
there were three sightings of approximately four individuals in upper
Cook Inlet (Lomac-MacNair et al. 2013). Marine mammal observers
associated with Buccaneer's drilling project off Cape Starichkof
observed seven Steller sea lions during the summer of 2013 (Owl Ridge
2014). During SAExploration's 3D Seismic Program in 2015, four Steller
sea lions were observed in Cook Inlet. One sighting occurred between
the West and East Forelands, one near Nikiski and one northeast of the
North Foreland in the center of Cook Inlet (Kendall et al. 2015).
During NMFS Cook Inlet beluga whale aerial surveys from 2000-2016,
there were 39 sightings of 769 estimated individual Steller sea lions
in lower Cook Inlet (Shelden et al. 2017). Sightings of large
congregations of Steller sea lions during NMFS aerial surveys occurred
outside the Petition region, on land in the mouth of Cook Inlet (e.g.,
Elizabeth and Shaw Islands).
California Sea Lions
There is limited information on the presence of California sea
lions in Alaska. From 1973 to 2003, a total of 52 California sea lions
were reported in Alaska, with sightings increasing in the later years.
Most sightings occurred in the spring; however, they have been observed
during all seasons. California sea lion presence in Alaska was
correlated with increasing population numbers within their southern
breeding range (Maniscalco et al. 2004).
There have been relatively few California sea lions observed in
Alaska, most are often alone or occasionally in small groups of two or
more and usually associated with Steller sea lions at their haulouts
and rookeries (Maniscalco et al. 2004). California sea lions are not
typically observed farther north than southeast Alaska, and sightings
are very rare in Cook Inlet. California sea lions have not been
observed during the annual NMFS aerial surveys in Cook Inlet. However,
a sighting of two California sea lions was documented during the Apache
2012 seismic survey (Lomac-MacNair et al. 2013). Additionally, NMFS'
anecdotal sighting
[[Page 12343]]
database has four sightings in Seward and Kachemak Bay.
The California sea lion breeds from the southern Baja Peninsula
north to A[ntilde]o Nuevo Island, California. Breeding season lasts
from May to August, and most pups are born from May through July. Their
nonbreeding range extends northward into British Columbia and
occasionally farther north into Alaskan waters. California sea lions
have been observed in Alaska during all four seasons; however, most of
the sightings have occurred during the spring (Maniscalco et al. 2004).
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS's Stock Assessment Reports (SAR; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region), and more general information about
these species (e.g., physical and behavioral descriptions) may be found
on NMFS' website (https://www.fisheries.noaa.gov/species-directory/).
Table 2 lists all species with expected potential for occurrence in
Cook Inlet and summarizes information related to the population or
stock, including regulatory status under the MMPA and ESA and potential
biological removal (PBR), where known. For taxonomy, we follow
Committee on Taxonomy (2016). PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no mortality is anticipated or authorized here, PBR and
annual serious injury and mortality from anthropogenic sources are
included here as gross indicators of the status of the species and
other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' 2017 U.S. Alaska and Pacific SARs (Muto et al, 2017; Carretta et
al, 2017). All values presented in Table 2 are the most recent
available at the time of publication and are available in the 2017 SARs
and draft 2018 SARs (available online at: https://www.fisheries.noaa.gov/action/2018-draft-marine-mammal-stock-assessment-reports-available).
Table 2--Species With the Potential To Occur in Cook Inlet, Alaska
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance (CV,
Common name Scientific name Stock ESA/ MMPA status; Nmin, most recent PBR Annual M/
Strategic (Y/N)\1\ abundance survey) \2\ SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray whale...................... Eschrichtius robustus.. Eastern Pacific........ -/-; N 20,990 (0.05, 20,125, 624 4.25
2011).
Family Balaenopteridae (rorquals):
Fin whale....................... Balaenoptera physalus.. Northeastern Pacific... E/D; Y 3,168 (0.26,2,554 5.1 0.4
2013).
Minke whale..................... Balaenoptera Alaska................. -/-; N N/A................... N/A 0
acutorostrata.
Humpback whale.................. Megaptera novaeangliae. Western North Pacific.. E/D; Y 1,107 (0.3, 865, 2006) 3 3.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Beluga whale.................... Delphinapterus leucas.. Cook Inlet............. E/D; Y 312 (0.1, 287, 2014).. 0.54 0.57
Killer whale.................... Orcinus orca........... Alaska Resident........ -/-; N 2,347 (N/A, 2,347, 24 1
2012).
Alaska Transient....... -/-; N 587 (N/A, 587, 2012).. 5.9 1
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Alaska......... -/-; Y 31,046 (0.214, N/A, Undet 72
1998).
Dall's porpoise................. Phocoenoides dalli..... Alaska................. -/-; N 83,400 (0.097, N/A, Undet 38
1993).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
Steller sea lion................ Eumetopias jubatus..... Western................ E/D; Y 53,303 (N/A, 53,303, 320 241
2016).
California sea lion............. Zalophus californianus. U.S.................... -/-; N 296,750 (153,337, N/A, 9,200 331
2011).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Cook Inlet/Shelikof.... -/-; N 27,386 (25,651, N/A, 770 234
2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
stock abundance. In some cases, CV is not applicable [explain if this is the case]
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated
with estimated mortality due to commercial fisheries is presented in some cases.
Note: Italicized species are not expected to be taken or proposed for authorization.
All species that could potentially occur in the proposed survey
areas are included in Table 2. As described below, all 11 species (with
12 managed stocks) temporally and spatially co-occur with the activity
to the degree that
[[Page 12344]]
take is reasonably likely to occur, and we have proposed authorizing
it.
In addition, sea otters may be found in Cook Inlet. However, sea
otters are managed by the U.S. Fish and Wildlife Service and are not
considered further in this document.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65 dB
threshold from the normalized composite audiograms, with the exception
for lower limits for low-frequency cetaceans where the lower bound was
deemed to be biologically implausible and the lower bound from Southall
et al. (2007) retained. The functional groups and the associated
frequencies are indicated below (note that these frequency ranges
correspond to the range for the composite group, with the entire range
not necessarily reflecting the capabilities of every species within
that group):
Low-frequency cetaceans (mysticetes): generalized hearing
is estimated to occur between approximately 7 Hz and 35 kHz;
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): generalized hearing is estimated to occur
between approximately 150 Hz and 160 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; including two members
of the genus Lagenorhynchus, on the basis of recent echolocation data
and genetic data): generalized hearing is estimated to occur between
approximately 275 Hz and 160 kHz;
Pinnipeds in water; Phocidae (true seals): generalized
hearing is estimated to occur between approximately 50 Hz to 86 kHz;
and
Pinnipeds in water; Otariidae (eared seals): generalized
hearing is estimated to occur between 60 Hz and 39 kHz.
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Eleven marine mammal species (eight cetacean and three pinniped (two
otariid and one phocid) species) have the reasonable potential to co-
occur with the proposed survey activities. Please refer to Table 2. Of
the cetacean species that may be present, four are classified as low-
frequency cetaceans (i.e., all mysticete species), two are classified
as mid-frequency cetaceans (i.e., all delphinid and ziphiid species and
the sperm whale), and two are classified as high-frequency cetaceans
(i.e., harbor porpoise and Kogia spp.).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take by Incidental Harassment section
later in this document includes a quantitative analysis of the number
of individuals that are expected to be taken by this activity. The
Negligible Impact Analysis and Determination section considers the
content of this section, the Estimated Take by Incidental Harassment
section, and the Proposed Mitigation section, to draw conclusions
regarding the likely impacts of these activities on the reproductive
success or survivorship of individuals and how those impacts on
individuals are likely to impact marine mammal species or stocks.
Description of Active Acoustic Sound Sources
This section contains a brief technical background on sound, the
characteristics of certain sound types, and on metrics used in this
proposal in as much as the information is relevant to the specified
activity and to a discussion of the potential effects of the specified
activity on marine mammals found later in this document.
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in Hz or cycles per second. Wavelength is the distance
between two peaks or corresponding points of a sound wave (length of
one cycle). Higher frequency sounds have shorter wavelengths than lower
frequency sounds, and typically attenuate (decrease) more rapidly,
except in certain cases in shallower water. Amplitude is the height of
the sound pressure wave or the ``loudness'' of a sound and is typically
described using the relative unit of the dB. A sound pressure level
(SPL) in dB is described as the ratio between a measured pressure and a
reference pressure (for underwater sound, this is 1 microPascal
([mu]Pa)) and is a logarithmic unit that accounts for large variations
in amplitude; therefore, a relatively small change in dB corresponds to
large changes in sound pressure. The source level (SL) represents the
SPL referenced at a distance of 1 m from the source (referenced to 1
[mu]Pa) while the received level is the SPL at the listener's position
(referenced to 1 [mu]Pa).
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Root mean square is calculated by squaring
all of the sound amplitudes, averaging the squares, and then taking the
square root of the average (Urick, 1983). Root mean square accounts for
both positive and negative values; squaring the pressures makes all
values positive so that they may be accounted for in the summation of
pressure levels (Hastings and Popper, 2005). This measurement is often
used in the context of discussing behavioral effects, in part because
behavioral effects, which often result from auditory cues, may be
better expressed through averaged units than by peak pressures.
Sound exposure level (SEL; represented as dB re 1 [mu]Pa2-s)
represents the total energy contained within a pulse and considers both
intensity and duration of exposure. Peak sound pressure (also referred
to as zero-to-peak sound pressure or 0-p) 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.
Another common metric is peak-to-peak sound pressure (pk-pk), which is
the algebraic difference between the peak positive and peak negative
sound pressures.
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Peak-to-peak pressure is typically approximately 6 dB higher than peak
pressure (Southall et al., 2007).
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in a
manner similar to ripples on the surface of a pond and may be either
directed in a beam or beams or may radiate in all directions
(omnidirectional sources), as is the case for pulses produced by the
airgun arrays considered here. The compressions and decompressions
associated with sound waves are detected as changes in pressure by
aquatic life and man-made sound receptors such as hydrophones.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound. Ambient
sound is defined as environmental background sound levels lacking a
single source or point (Richardson et al., 1995), and the sound level
of a region is defined by the total acoustical energy being generated
by known and unknown sources. These sources may include physical (e.g.,
wind and waves, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic (e.g., vessels, dredging, construction) sound. A number
of sources contribute to ambient sound, including the following
(Richardson et al., 1995):
Wind and waves: The complex interactions between wind and
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of
naturally occurring ambient sound for frequencies between 200 Hz and 50
kilohertz (kHz) (Mitson, 1995). In general, ambient sound levels tend
to increase with increasing wind speed and wave height. Surf sound
becomes important near shore, with measurements collected at a distance
of 8.5 km from shore showing an increase of 10 dB in the 100 to 700 Hz
band during heavy surf conditions;
Precipitation: Sound from rain and hail impacting the
water surface can become an important component of total sound at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times;
Biological: Marine mammals can contribute significantly to
ambient sound levels, as can some fish and snapping shrimp. The
frequency band for biological contributions is from approximately 12 Hz
to over 100 kHz; and
Anthropogenic: Sources of ambient sound related to human
activity include transportation (surface vessels), dredging and
construction, oil and gas drilling and production, seismic surveys,
sonar, explosions, and ocean acoustic studies. Vessel noise typically
dominates the total ambient sound for frequencies between 20 and 300
Hz. In general, the frequencies of anthropogenic sounds are below 1 kHz
and, if higher frequency sound levels are created, they attenuate
rapidly. Sound from identifiable anthropogenic sources other than the
activity of interest (e.g., a passing vessel) is sometimes termed
background sound, as opposed to ambient sound.
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
human activity) but also on the ability of sound to propagate through
the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from a given
activity may be a negligible addition to the local environment or could
form a distinctive signal that may affect marine mammals. Details of
source types are described in the following text.
Sounds are often considered to fall into one of two general types:
Pulsed and non-pulsed (defined in the following). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see
Southall et al. (2007) for an in-depth discussion of these concepts.
Pulsed sound sources (e.g., airguns, explosions, gunshots, sonic
booms, impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur
either as isolated events or repeated in some succession. Pulsed sounds
are all characterized by a relatively rapid rise from ambient pressure
to a maximal pressure value followed by a rapid decay period that may
include a period of diminishing, oscillating maximal and minimal
pressures and generally have an increased capacity to induce physical
injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or non-continuous (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems (such as
those used by the U.S. Navy). The duration of such sounds, as received
at a distance, can be greatly extended in a highly reverberant
environment.
Airgun arrays produce pulsed signals with energy in a frequency
range from about 10-2,000 Hz, with most energy radiated at frequencies
below 200 Hz. The amplitude of the acoustic wave emitted from the
source is equal in all directions (i.e., omnidirectional), but airgun
arrays do possess some directionality due to different phase delays
between guns in different directions. Airgun arrays are typically tuned
to maximize functionality for data acquisition purposes, meaning that
sound transmitted in horizontal directions and at higher frequencies is
minimized to the extent possible.
As described above, two types of sub-bottom profiler would also be
used by Hilcorp during the geotechnical and geohazard surveys: A low
resolution unit (1-4 kHz) and a high resolution unit (2-24 kHz).
Potential Effects of Underwater Sound--Please refer to the
information given previously (``Description of Active Acoustic Sound
Sources'') regarding sound, characteristics of sound types, and metrics
used in this document. Note that, in the following discussion, we refer
in many cases to a recent review article concerning studies of noise-
induced hearing loss conducted from 1996-2015 (i.e., Finneran, 2015).
For study-specific citations, please see that work. Anthropogenic
sounds cover a broad range of frequencies and sound levels and can have
a range of highly variable impacts on marine life, from none or minor
to potentially severe responses, depending on received levels, duration
of exposure, behavioral context, and various other factors. The
potential effects of underwater sound
[[Page 12346]]
from active acoustic sources can potentially result in one or more of
the following: Temporary or permanent hearing impairment, non-auditory
physical or physiological effects, behavioral disturbance, stress, and
masking (Richardson et al., 1995; Gordon et al., 2004; Nowacek et al.,
2007; Southall et al., 2007; G[ouml]tz et al., 2009). The degree of
effect is intrinsically related to the signal characteristics, received
level, distance from the source, and duration of the sound exposure. In
general, sudden, high level sounds can cause hearing loss, as can
longer exposures to lower level sounds. Temporary or permanent loss of
hearing will occur almost exclusively for noise within an animal's
hearing range. We first describe specific manifestations of acoustic
effects before providing discussion specific to the use of airguns.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur, in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the masking zone may be highly variable in size.
We describe the more severe effects certain non-auditory physical
or physiological effects only briefly as we do not expect that use of
airgun arrays, sub-bottom profilers, drill rig construction, or sheet
pile driving are reasonably likely to result in such effects (see below
for further discussion). Potential effects from impulsive sound sources
can range in severity from effects such as behavioral disturbance or
tactile perception to physical discomfort, slight injury of the
internal organs and the auditory system, or mortality (Yelverton et
al., 1973). Non-auditory physiological effects or injuries that
theoretically might occur in marine mammals exposed to high level
underwater sound or as a secondary effect of extreme behavioral
reactions (e.g., change in dive profile as a result of an avoidance
reaction) caused by exposure to sound include neurological effects,
bubble formation, resonance effects, and other types of organ or tissue
damage (Cox et al., 2006; Southall et al., 2007; Zimmer and Tyack,
2007; Tal et al., 2015). The suite of activities considered here do not
involve the use of devices such as explosives or mid-frequency tactical
sonar that are associated with these types of effects.
1. Threshold Shift--Marine mammals exposed to high-intensity sound,
or to lower-intensity sound for prolonged periods, can experience
hearing threshold shift (TS), which is the loss of hearing sensitivity
at certain frequency ranges (Finneran, 2015). TS can be permanent
(PTS), in which case the loss of hearing sensitivity is not fully
recoverable, or temporary (TTS), in which case the animal's hearing
threshold would recover over time (Southall et al., 2007). Repeated
sound exposure that leads to TTS could cause PTS. In severe cases of
PTS, there can be total or partial deafness, while in most cases the
animal has an impaired ability to hear sounds in specific frequency
ranges (Kryter, 1985).
When PTS occurs, there is physical damage to the sound receptors in
the ear (i.e., tissue damage), whereas TTS represents primarily tissue
fatigue and is reversible (Southall et al., 2007). In addition, other
investigators have suggested that TTS is within the normal bounds of
physiological variability and tolerance and does not represent physical
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to
constitute auditory injury.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals. There is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above (a 40-dB threshold shift approximates PTS onset;
e.g., Kryter et al., 1966; Miller, 1974) which would induce mild TTS (a
6-dB threshold shift approximates TTS onset; e.g., Southall et al.
2007). Based on data from terrestrial mammals, a precautionary
assumption is that the PTS thresholds for impulse sounds (such as
airgun pulses as received close to the source) are at least 6 dB higher
than the TTS threshold on a peak-pressure basis, and PTS cumulative
sound exposure level (SELcum) thresholds are 15 to 20 dB higher than
TTS SELcum thresholds (Southall et al., 2007). Given the higher level
of sound combined with longer exposure duration necessary to cause PTS,
it is expected that limited PTS could occur from the proposed
activities. For mid-frequency cetaceans in particular, potential
protective mechanisms may help limit onset of TTS or prevent onset of
PTS. Such mechanisms include dampening of hearing, auditory adaptation,
or behavioral amelioration (e.g., Nachtigall and Supin, 2013; Miller et
al., 2012; Finneran et al., 2015; Popov et al., 2016). Given the higher
level of sound, longer durations of exposure necessary to cause PTS, it
is possible but unlikely PTS would occur during the proposed seismic
surveys, geotechnical surveys, or other exploratory drilling
activities.
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. Few data
on sound levels and durations necessary to elicit mild TTS have been
obtained for marine mammals.
Marine mammal hearing plays a critical role in communication with
conspecifics, and interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS, and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to
serious. For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that occurs during a time where ambient noise is lower and there
are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts.
Finneran et al. (2015) measured hearing thresholds in three captive
bottlenose dolphins before and after exposure to ten pulses produced by
a seismic airgun in order to study TTS induced after exposure to
multiple pulses. Exposures began at relatively low levels and gradually
increased over a period of several months, with the highest exposures
at peak SPLs from 196 to 210 dB and cumulative (unweighted) SELs from
193-195 dB. No substantial TTS was observed. In addition, behavioral
reactions were
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observed that indicated that animals can learn behaviors that
effectively mitigate noise exposures (although exposure patterns must
be learned, which is less likely in wild animals than for the captive
animals considered in this study). The authors note that the failure to
induce more significant auditory effects is likely due to the
intermittent nature of exposure, the relatively low peak pressure
produced by the acoustic source, and the low-frequency energy in airgun
pulses as compared with the frequency range of best sensitivity for
dolphins and other mid-frequency cetaceans.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis)) and five species of pinnipeds (northern elephant
seal, harbor seal, and California sea lion) exposed to a limited number
of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran, 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran, 2015). Additionally, the existing marine mammal TTS data
come from a limited number of individuals within these species. There
are no data available on noise-induced hearing loss for mysticetes. For
summaries of data on TTS in marine mammals or for further discussion of
TTS onset thresholds, please see Southall et al. (2007), Finneran and
Jenkins (2012), Finneran (2015), and Table 5 in NMFS (2018).
Critical questions remain regarding the rate of TTS growth and
recovery after exposure to intermittent noise and the effects of single
and multiple pulses. Data at present are also insufficient to construct
generalized models for recovery and determine the time necessary to
treat subsequent exposures as independent events. More information is
needed on the relationship between auditory evoked potential and
behavioral measures of TTS for various stimuli. For summaries of data
on TTS in marine mammals or for further discussion of TTS onset
thresholds, please see Southall et al. (2007), Finneran and Jenkins
(2012), Finneran (2015), and NMFS (2016).
Marine mammals in the action area during the proposed activities
are less likely to incur TTS hearing impairment from some of the
sources proposed to be used due to the characteristics of the sound
sources, particularly sources such as the water jets, which include
lower source levels (176 dB @1m) and generally very short pulses and
duration of the sound. Even for high-frequency cetacean species (e.g.,
harbor porpoises), which may have increased sensitivity to TTS (Lucke
et al., 2009; Kastelein et al., 2012b), individuals would have to make
a very close approach and also remain very close to vessels operating
these sources in order to receive multiple exposures at relatively high
levels, as would be necessary to cause TTS. Intermittent exposures--as
would occur due to the brief, transient signals produced by these
sources--require a higher cumulative SEL to induce TTS than would
continuous exposures of the same duration (i.e., intermittent exposure
results in lower levels of TTS) (Mooney et al., 2009a; Finneran et al.,
2010). Moreover, most marine mammals would more likely avoid a loud
sound source rather than swim in such close proximity as to result in
TTS (much less PTS). Kremser et al. (2005) noted that the probability
of a cetacean swimming through the area of exposure when a sub-bottom
profiler emits a pulse is small--because if the animal was in the area,
it would have to pass the transducer at close range in order to be
subjected to sound levels that could cause temporary threshold shift
and would likely exhibit avoidance behavior to the area near the
transducer rather than swim through at such a close range. Further, the
restricted beam shape of the sub-bottom profiler and other geophysical
survey equipment makes it unlikely that an animal would be exposed more
than briefly during the passage of the vessel. Boebel et al. (2005)
concluded similarly for single and multibeam echosounders, and more
recently, Lurton (2016) conducted a modeling exercise and concluded
similarly that likely potential for acoustic injury from these types of
systems is negligible, but that behavioral response cannot be ruled
out. Animals may avoid the area around the survey vessels, thereby
reducing exposure. Effects of non-pulsed sound on marine mammals, such
as vibratory pile driving, are less studied. In a study by Malme et al.
(1986) on gray whales as well as Richardson et al. (1997) on beluga
whales, the only reactions documented in response to drilling sound
playbacks were behavioral reactions. Any disturbance to marine mammals
is likely to be in the form of temporary avoidance or alteration of
opportunistic foraging behavior near the survey location.
2. Behavioral Effects--Behavioral disturbance may include a variety
of effects, including subtle changes in behavior (e.g., minor or brief
avoidance of an area or changes in vocalizations), more conspicuous
changes in similar behavioral activities, and more sustained and/or
potentially severe reactions, such as displacement from or abandonment
of high-quality habitat. Behavioral responses to sound are highly
variable and context-specific and any reactions depend on numerous
intrinsic and extrinsic factors (e.g., species, state of maturity,
experience, current activity, reproductive state, auditory sensitivity,
time of day), as well as the interplay between factors (e.g.,
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007;
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not
only among individuals but also within an individual, depending on
previous experience with a sound source, context, and numerous other
factors (Ellison et al., 2012), and can vary depending on
characteristics associated with the sound source (e.g., whether it is
moving or stationary, number of sources, distance from the source).
Please see Appendices B-C of Southall et al. (2007) for a review of
studies involving marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure. As noted, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997).
Observed responses of wild marine mammals to
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loud pulsed sound sources (typically seismic airguns or acoustic
harassment devices) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
However, many delphinids approach acoustic source vessels with no
apparent discomfort or obvious behavioral change (e.g., Barkaszi et
al., 2012).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely, and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark 2000; Ng and Leung 2003; Nowacek et al. 2004; Goldbogen et
al. 2013). Variations in dive behavior may reflect interruptions in
biologically significant activities (e.g., foraging) or they may be of
little biological significance. The impact of an alteration to dive
behavior resulting from an acoustic exposure depends on what the animal
is doing at the time of the exposure and the type and magnitude of the
response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.
2001; Nowacek et al. 2004; Madsen et al. 2006; Yazvenko et al. 2007). A
determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Visual tracking, passive acoustic monitoring, and movement
recording tags were used to quantify sperm whale behavior prior to,
during, and following exposure to airgun arrays at received levels in
the range 140-160 dB at distances of 7-13 km, following a phase-in of
sound intensity and full array exposures at 1-13 km (Madsen et al.,
2006; Miller et al., 2009). Sperm whales did not exhibit horizontal
avoidance behavior at the surface. However, foraging behavior may have
been affected. The sperm whales exhibited 19 percent less vocal (buzz)
rate during full exposure relative to post exposure, and the whale that
was approached most closely had an extended resting period and did not
resume foraging until the airguns had ceased firing. The remaining
whales continued to execute foraging dives throughout exposure;
however, swimming movements during foraging dives were six percent
lower during exposure than control periods (Miller et al., 2009). These
data raise concerns that seismic surveys may impact foraging behavior
in sperm whales, although more data are required to understand whether
the differences were due to exposure or natural variation in sperm
whale behavior (Miller et al., 2009).
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the tolerance of underwater noise
when determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et
al., 2007).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Cerchio et al. (2014) used passive acoustic monitoring to document
the presence of singing humpback whales off the coast of northern
Angola and to opportunistically test for the effect of seismic survey
activity on the number of singing whales. Two recording units were
deployed between March and December 2008 in the offshore environment,
and the numbers of singers were counted every hour. Generalized
Additive Mixed Models were used to assess the effect of survey day
(seasonality), hour (diel variation), moon phase, and received levels
of noise (measured from a single pulse during each ten minute sampled
period) on singer number. The number of singers significantly decreased
with increasing received level of noise, suggesting that humpback whale
breeding activity was disrupted to some extent by the survey activity.
Castellote et al. (2012) reported acoustic and behavioral changes
by fin whales in response to shipping and airgun noise. Acoustic
features of fin whale song notes recorded in the Mediterranean Sea and
northeast Atlantic Ocean were compared for areas with different
shipping noise levels and traffic intensities and during a seismic
airgun survey. During the first 72 hours of the survey, a steady
decrease in song received levels and bearings to singers indicated that
whales moved away from the acoustic source and out of the study area.
This displacement persisted for a time period well beyond the 10-day
duration of seismic airgun activity, providing evidence that fin whales
may avoid an area for an extended period in the presence of increased
noise. The authors hypothesize that fin whale acoustic communication is
modified to compensate for increased background noise and that a
sensitization process may play a role in the observed temporary
displacement.
[[Page 12349]]
Seismic pulses at average received levels of 131 dB re 1
[micro]Pa2-s caused blue whales to increase call production (Di Iorio
and Clark, 2010). In contrast, McDonald et al. (1995) tracked a blue
whale with seafloor seismometers and reported that it stopped
vocalizing and changed its travel direction at a range of 10 km from
the acoustic source vessel (estimated received level 143 dB pk-pk).
Blackwell et al. (2013) found that bowhead whale call rates dropped
significantly at onset of airgun use at sites with a median distance of
41-45 km from the survey. Blackwell et al. (2015) expanded this
analysis to show that whales actually increased calling rates as soon
as airgun signals were detectable before ultimately decreasing calling
rates at higher received levels (i.e., 10-minute SELcum of ~127 dB).
Overall, these results suggest that bowhead whales may adjust their
vocal output in an effort to compensate for noise before ceasing
vocalization effort and ultimately deflecting from the acoustic source
(Blackwell et al., 2013, 2015). These studies demonstrate that even low
levels of noise received far from the source can induce changes in
vocalization and/or behavior for mysticetes.
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Humpback whales showed avoidance behavior in the presence of an
active seismic array during observational studies and controlled
exposure experiments in western Australia (McCauley et al., 2000).
Avoidance may be short-term, with animals returning to the area once
the noise has ceased (e.g., Bowles et al., 1994; Stone et al., 2000;
Morton and Symonds, 2002; Gailey et al., 2007). Longer-term
displacement is possible, however, which may lead to changes in
abundance or distribution patterns of the affected species in the
affected region if habituation to the presence of the sound does not
occur (e.g., Bejder et al., 2006; Teilmann et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine mammal strandings
(Evans and England, 2001). However, it should be noted that response to
a perceived predator does not necessarily invoke flight (Ford and
Reeves, 2008), and whether individuals are solitary or in groups may
influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil 1997; Purser and Radford 2011). In addition, chronic
disturbance can cause population declines through reduction of fitness
(e.g., decline in body condition) and subsequent reduction in
reproductive success, survival, or both (e.g., Harrington and Veitch
1992; Daan et al. 1996; Bradshaw et al. 1998). However, Ridgway et al.
(2006) reported that increased vigilance in bottlenose dolphins exposed
to sound over a five-day period did not cause any sleep deprivation or
stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Stone (2015) reported data from at-sea observations during 1,196
seismic surveys from 1994 to 2010. When large arrays of airguns
(considered to be 500 cui or more) were firing, lateral displacement,
more localized avoidance, or other changes in behavior were evident for
most odontocetes. However, significant responses to large arrays were
found only for the minke whale and fin whale. Behavioral responses
observed included changes in swimming or surfacing behavior, with
indications that cetaceans remained near the water surface at these
times. Cetaceans were recorded as feeding less often when large arrays
were active. Behavioral observations of gray whales during a seismic
survey monitored whale movements and respirations pre-, during and
post-seismic survey (Gailey et al., 2016). Behavioral state and water
depth were the best `natural' predictors of whale movements and
respiration and, after considering natural variation, none of the
response variables were significantly associated with seismic survey or
vessel sounds.
Marine mammals are likely to avoid the proposed activities,
especially harbor porpoises, while the harbor seals might be attracted
to them out of curiosity. However, because the sub-bottom profilers and
seismic equipment operate from moving vessels, the area (relative to
the available habitat in Cook Inlet) and time that this equipment would
be affecting a given location is very small. Further, for mobile
sources, once an area has been surveyed, it is not likely that it will
be surveyed again, therefore reducing the likelihood of repeated
geophysical and geotechnical survey impacts within the survey area. The
isopleths for harassment for the stationary sources considered in this
document are small relative to those for mobile sources. Therefore,
while the sound is concentrated in the same area for the duration of
the activity (duration of pile driving, VSP, etc), the amount of area
affected by noise levels which we expect may cause harassment are small
relative to the mobile sources. Additionally, animals may more
predictably avoid the area of the disturbance as the source is
stationary. Overall duration of these sound sources is still short and
unlikely to cause more than temporary disturbance.
We have also considered the potential for severe behavioral
responses such as stranding and associated indirect injury or mortality
from Hilcorp's use of high resolution geophysical survey equipment, on
the basis of a 2008 mass stranding of approximately one hundred melon-
headed whales in a Madagascar lagoon system. An investigation of the
[[Page 12350]]
event indicated that use of a high-frequency mapping system (12-kHz
multibeam echosounder) was the most plausible and likely initial
behavioral trigger of the event, while providing the caveat that there
is no unequivocal and easily identifiable single cause (Southall et
al., 2013). The investigatory panel's conclusion was based on (1) very
close temporal and spatial association and directed movement of the
survey with the stranding event; (2) the unusual nature of such an
event coupled with previously documented apparent behavioral
sensitivity of the species to other sound types (Southall et al., 2006;
Brownell et al., 2009); and (3) the fact that all other possible
factors considered were determined to be unlikely causes. Specifically,
regarding survey patterns prior to the event and in relation to
bathymetry, the vessel transited in a north-south direction on the
shelf break parallel to the shore, ensonifying large areas of deep-
water habitat prior to operating intermittently in a concentrated area
offshore from the stranding site. This may have trapped the animals
between the sound source and the shore, thus driving them towards the
lagoon system. The investigatory panel systematically excluded or
deemed highly unlikely nearly all potential reasons for these animals
leaving their typical pelagic habitat for an area extremely atypical
for the species (i.e., a shallow lagoon system). Notably, this was the
first time that such a system has been associated with a stranding
event. The panel also noted several site- and situation-specific
secondary factors that may have contributed to the avoidance responses
that led to the eventual entrapment and mortality of the whales.
Specifically, shoreward-directed surface currents and elevated
chlorophyll levels in the area preceding the event may have played a
role (Southall et al., 2013). The report also notes that prior use of a
similar system in the general area may have sensitized the animals and
also concluded that, for odontocete cetaceans that hear well in higher
frequency ranges where ambient noise is typically quite low, high-power
active sonars operating in this range may be more easily audible and
have potential effects over larger areas than low frequency systems
that have more typically been considered in terms of anthropogenic
noise impacts. It is, however, important to note that the relatively
lower output frequency, higher output power, and complex nature of the
system implicated in this event, in context of the other factors noted
here, likely produced a fairly unusual set of circumstances that
indicate that such events would likely remain rare and are not
necessarily relevant to use of lower-power, higher-frequency systems
more commonly used for high resolution geophysical (HRG) survey
applications. The risk of similar events recurring may be very low,
given the extensive use of active acoustic systems used for scientific
and navigational purposes worldwide on a daily basis and the lack of
direct evidence of such responses previously reported.
3. Stress Responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg 1987; Blecha
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al. 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficiently to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Lankford et al., 2005). Stress responses due to exposure to
anthropogenic sounds or other stressors and their effects on marine
mammals have also been reviewed (Fair and Becker, 2000; Romano et al.,
2002) and, more rarely, studied in wild populations (e.g., Romano et
al., 2002). For example, Rolland et al. (2012) found that noise
reduction from reduced ship traffic in the Bay of Fundy was associated
with decreased stress in North Atlantic right whales. These and other
studies lead to a reasonable expectation that some marine mammals will
experience physiological stress responses upon exposure to acoustic
stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003).
In general, there are few data on the potential for strong,
anthropogenic underwater sounds to cause non-auditory physical effects
in marine mammals. Such effects, if they occur at all, would presumably
be limited to short distances and to activities that extend over a
prolonged period. The available data do not allow identification of a
specific exposure level above which non-auditory effects can be
expected (Southall et al., 2007). There is no definitive evidence that
any of these effects occur even for marine mammals in close proximity
to an anthropogenic sound source. In addition, marine mammals that show
behavioral avoidance of survey vessels and related sound sources, are
unlikely to incur non-auditory impairment or other physical effects.
NMFS does not expect that the generally short-term, intermittent, and
transitory seismic and geophysical surveys would create conditions of
long-term, continuous noise and chronic acoustic exposure leading to
long-term physiological stress responses in marine mammals. While the
noise from drilling related activities are more continuous and longer
term, those sounds are generated at a much lower level than the mobile
sources discussed earlier.
4. Auditory Masking--Sound can disrupt behavior through masking, or
interfering with, an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance,
[[Page 12351]]
navigation) (Richardson et al., 1995; Erbe et al., 2016). Masking
occurs when the receipt of a sound is interfered with by another
coincident sound at similar frequencies and at similar or higher
intensity, and may occur whether the sound is natural (e.g., snapping
shrimp, wind, waves, precipitation) or anthropogenic (e.g., shipping,
sonar, seismic exploration) in origin. The ability of a noise source to
mask biologically important sounds depends on the characteristics of
both the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions.
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is man-made, it may be considered harassment
when disrupting or altering critical behaviors. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which occurs during the sound exposure. Because masking
(without resulting in TS) is not associated with abnormal physiological
function, it is not considered a physiological effect, but rather a
potential behavioral effect.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds, such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al. 2000;
Foote et al. 2004; Parks et al. 2007; Holt et al. 2009). Masking can be
reduced in situations where the signal and noise come from different
directions (Richardson et al. 1995), through amplitude modulation of
the signal, or through other compensatory behaviors (Houser and Moore
2014). Masking can be tested directly in captive species (e.g., Erbe
2008) but, in wild populations, it must be either modeled or inferred
from evidence of masking compensation. There are few studies addressing
real-world masking sounds likely to be experienced by marine mammals in
the wild (e.g., Branstetter et al. 2013).
Masking affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand 2009). All anthropogenic sound sources, but especially
chronic and lower-frequency signals (e.g., from vessel traffic),
contribute to elevated ambient sound levels, thus intensifying masking.
Marine mammal communications would not likely be masked appreciably
by the sub-profiler or seismic survey's signals given the
directionality of the signal and the brief period when an individual
mammal is likely to be within its beam. The probability for conductor
pipe driving masking acoustic signals important to the behavior and
survival of marine mammal species is low. Vibratory pile driving is
also relatively short-term, with rapid oscillations occurring for short
durations. It is possible that vibratory pile driving resulting from
this proposed action may mask acoustic signals important to the
behavior and survival of marine mammal species, but the short-term
duration and limited affected area would result in insignificant
impacts from masking. Any masking event that could possibly rise to
Level B harassment under the MMPA would occur concurrently within the
zones of behavioral harassment already estimated for vibratory pile and
conductor pipe driving, and which have already been taken into account
in the exposure analysis. Pile driving would occur for limited
durations across multiple widely dispersed sites, thus we do not
anticipate masking to significantly affect marine mammals.
Ship Strike
Vessel collisions with marine mammals, or ship strikes, can result
in death or serious injury of the animal. 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. Superficial strikes may not kill or result in
the death of the animal. These interactions are typically associated
with large whales (e.g., fin whales), which are occasionally found
draped across the bulbous bow of large commercial ships upon arrival in
port. Although smaller cetaceans are more maneuverable in relation to
large vessels than are large whales, they may also be susceptible to
strike. The severity of injuries typically depends on the size and
speed of the vessel, with the probability of death or serious injury
increasing as vessel speed increases (Knowlton and Kraus 2001; Laist et
al. 2001; Vanderlaan and Taggart 2007; Conn and Silber 2013). Impact
forces increase with speed, as does the probability of a strike at a
given distance (Silber et al. 2010; Gende et al. 2011).
Pace and Silber (2005) also found that the probability of death or
serious injury increased rapidly with increasing vessel speed.
Specifically, the predicted probability of serious injury or death
increased from 45 to 75 percent as vessel speed increased from 10 to 14
kn, and exceeded 90 percent at 17 kn. Higher speeds during collisions
result in greater force of impact, but higher speeds also appear to
increase the chance of severe injuries or death through increased
likelihood of collision by pulling whales toward the vessel (Clyne and
Kennedy, 1999;). In a separate study, Vanderlaan and Taggart (2007)
analyzed the probability of lethal mortality of large whales at a given
speed, showing that the greatest rate of change in the probability of a
lethal injury to a large whale as a function of vessel speed occurs
between 8.6 and 15 kt. The chances of a lethal injury decline from
approximately 80 percent at 15 kt to approximately 20 percent at 8.6
kt. At speeds below 11.8 kt, the chances of lethal injury drop below 50
percent, while the probability asymptotically increases toward one
hundred percent above 15 kt.
Hilcorp's seismic vessels would travel at approximately 4 knots
(7.41 km/hour) while towing seismic survey gear and a maximum of 4.5
knots (8.3 km/hr) while conducting geotechnical and geohazard surveys
(Faithweather, 2018). At these speeds, both the possibility of striking
a marine mammal and the possibility of a strike resulting in serious
injury or mortality are discountable. At average transit speed, the
probability of serious injury or mortality resulting from a strike is
less than 50 percent. However, the likelihood of a strike actually
happening is again discountable. Ship strikes, as analyzed in the
studies cited
[[Page 12352]]
above, generally involve commercial shipping, which is much more common
in both space and time than is geophysical survey activity. Jensen and
Silber (2004) summarized ship strikes of large whales worldwide from
1975-2003 and found that most collisions occurred in the open ocean and
involved large vessels (e.g., commercial shipping). Commercial fishing
vessels were responsible for three percent of recorded collisions,
while no such incidents were reported for geophysical survey vessels
during that time period.
It is possible for ship strikes to occur while traveling at slow
speeds. For example, a hydrographic survey vessel traveling at low
speed (5.5 kt) while conducting mapping surveys off the central
California coast struck and killed a blue whale in 2009. The State of
California determined that the whale had suddenly and unexpectedly
surfaced beneath the hull, with the result that the propeller severed
the whale's vertebrae, and that this was an unavoidable event. This
strike represents the only such incident in approximately 540,000 hours
of similar coastal mapping activity (p = 1.9 x 10-6; 95% CI = 0-5.5 x
10-6; NMFS, 2013b). In addition, a research vessel reported a fatal
strike in 2011 of a dolphin in the Atlantic, demonstrating that it is
possible for strikes involving smaller cetaceans to occur. In that
case, the incident report indicated that an animal apparently was
struck by the vessel's propeller as it was intentionally swimming near
the vessel. While indicative of the type of unusual events that cannot
be ruled out, neither of these instances represents a circumstance that
would be considered reasonably foreseeable or that would be considered
preventable.
Although the likelihood of the vessel striking a marine mammal is
low, we require a robust ship strike avoidance protocol (see ``Proposed
Mitigation''), which we believe eliminates any foreseeable risk of ship
strike. We anticipate that vessel collisions involving a seismic data
acquisition vessel towing gear, while not impossible, represent
unlikely, unpredictable events for which there are no preventive
measures. Given the required mitigation measures, the relatively slow
speed of the vessel towing gear, the presence of marine mammal
observers, and the short duration of the survey, we believe that the
possibility of ship strike is discountable. Further, were a strike of a
large whale to occur, it would be unlikely to result in serious injury
or mortality. 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.
Stranding
When a living or dead marine mammal swims or floats onto shore and
becomes ``beached'' or incapable of returning to sea, the event is a
``stranding'' (Geraci et al. 1999; Perrin and Geraci 2002; Geraci and
Lounsbury 2005). The legal definition for a stranding under the MMPA is
(A) a marine mammal is dead and is (i) on a beach or shore of the
United States; or (ii) in waters under the jurisdiction of the United
States (including any navigable waters); or (B) a marine mammal is
alive and is (i) on a beach or shore of the United States and is unable
to return to the water; (ii) on a beach or shore of the United States
and, although able to return to the water, is in need of apparent
medical attention; or (iii) in the waters under the jurisdiction of the
United States (including any navigable waters), but is unable to return
to its natural habitat under its own power or without assistance.
Marine mammals strand for a variety of reasons, such as infectious
agents, biotoxicosis, starvation, fishery interaction, ship strike,
unusual oceanographic or weather events, sound exposure, or
combinations of these stressors sustained concurrently or in series.
However, the cause or causes of most strandings are unknown (Eaton,
1979; Best 1982). Numerous studies suggest that the physiology,
behavior, habitat relationships, age, or condition of cetaceans may
cause them to strand or might pre-dispose them to strand when exposed
to another phenomenon. These suggestions are consistent with the
conclusions of numerous other studies that have demonstrated that
combinations of dissimilar stressors commonly combine to kill an animal
or dramatically reduce its fitness, even though one exposure without
the other does not produce the same result (Fair and Becker 2000;
Moberg, 2000; Romero 2004; Sih et al. 2004).
Use of military tactical sonar has been implicated in a majority of
investigated stranding events, although one stranding event was
associated with the use of seismic airguns. This event occurred in the
Gulf of California, coincident with seismic reflection profiling by the
R/V Maurice Ewing operated by Lamont-Doherty Earth Observatory (LDEO)
of Columbia University and involved two Cuvier's beaked whales
(Hildebrand 2004). The vessel had been firing an array of 20 airguns
with a total volume of 8,500 cui (Hildebrand 2004). Most known
stranding events have involved beaked whales, though a small number
have involved deep-diving delphinids or sperm whales (e.g., Southall et
al. 2013). In general, long duration (~1 second) and high-intensity
sounds (>235 dB SPL) have been implicated in stranding events
(Hildebrand 2004). With regard to beaked whales, mid-frequency sound
has been implicated in a few specific cases (when causation can be
determined) (Hildebrand 2004). Although seismic airguns create
predominantly low-frequency energy, the signal does include a mid-
frequency component. Based on the information presented above, we have
considered the potential for the proposed survey to result in marine
mammal stranding and have concluded that, based on the best available
information, stranding is not expected to occur.
Other Potential Impacts
Here, we briefly address the potential risks due to entanglement
and contaminant spills. We are not aware of any records of marine
mammal entanglement in towed arrays such as those considered here. The
discharge of trash and debris is prohibited (33 CFR 151.51-77) unless
it is passed through a machine that breaks up solids such that they can
pass through a 25-mm mesh screen. All other trash and debris must be
returned to shore for proper disposal with municipal and solid waste.
Some personal items may be accidentally lost overboard. However, U.S.
Coast Guard and Environmental Protection Act regulations require
operators to become proactive in avoiding accidental loss of solid
waste items by developing waste management plans, posting informational
placards, manifesting trash sent to shore, and using special
precautions such as covering outside trash bins to prevent accidental
loss of solid waste. There are no meaningful entanglement risks posed
by the described activity, and entanglement risks are not discussed
further in this document.
Marine mammals could be affected by accidentally spilled diesel
fuel from a vessel associated with proposed survey activities.
Quantities of diesel fuel on the sea surface may affect marine mammals
through various pathways: Surface contact of the fuel with skin and
other mucous membranes, inhalation of concentrated petroleum vapors, or
ingestion of the fuel (direct ingestion or by the ingestion of oiled
prey) (e.g., Geraci and St. Aubin, 1980, 1990). However, the likelihood
of a fuel spill during any particular geophysical survey is considered
to be remote, and
[[Page 12353]]
the potential for impacts to marine mammals would depend greatly on the
size and location of a spill and meteorological conditions at the time
of the spill. Spilled fuel would rapidly spread to a layer of varying
thickness and break up into narrow bands or windows parallel to the
wind direction. The rate at which the fuel spreads would be determined
by the prevailing conditions such as temperature, water currents, tidal
streams, and wind speeds. Lighter, volatile components of the fuel
would evaporate to the atmosphere almost completely in a few days.
Evaporation rate may increase as the fuel spreads because of the
increased surface area of the slick. Rougher seas, high wind speeds,
and high temperatures also tend to increase the rate of evaporation and
the proportion of fuel lost by this process (Scholz et al., 1999). We
do not anticipate potentially meaningful effects to marine mammals as a
result of any contaminant spill resulting from the proposed survey
activities, and contaminant spills are not discussed further in this
document.
Similarly, marine mammals could be affected by spilled hazardous
materials generated by the drilling process. Large and small quantities
of hazardous materials, including diesel fuel and gasoline, would be
handled, transported, and stored following the rules and procedures
described in the Spill Prevention, Control, and Countermeasure (SPCC)
Plan. Spills and leaks of oil or wastewater arising from the proposed
activities that reach marine waters could result in direct impacts to
the health of exposed marine mammals. Individual marine mammals could
show acute irritation or damage to their eyes, blowhole or nares, and
skin; fouling of baleen, which could reduce feeding efficiency; and
respiratory distress from the inhalation of vapors (Geraci and St.
Aubin 1990). Long-term impacts from exposure to contaminants to the
endocrine system could impair health and reproduction (Geraci and St.
Aubin 1990). Ingestion of contaminants could cause acute irritation to
the digestive tract, including vomiting and aspiration into the lungs,
which could result in pneumonia or death (Geraci and St. Aubin 1990).
However, the measures outlined in Hilcorp's spill plan minimize the
risk of a spill such that we do not anticipate potentially meaningful
effects to marine mammals as a result of oil spills from this activity,
and oil spills are not discussed further in this document.
Anticipated Effects on Marine Mammal Habitat
Effects to Prey--Marine mammal prey varies by species, season, and
location and, for some, is not well documented. Fish react to sounds
which are especially strong and/or intermittent low-frequency sounds.
Short duration, sharp sounds can cause overt or subtle changes in fish
behavior and local distribution. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pulsed
sound on fish, although several are based on studies in support of
construction projects (e.g., Scholik and Yan 2001, 2002; Popper and
Hastings 2009). Sound pulses at received levels of 160 dB may cause
subtle changes in fish behavior, although the behavioral threshold
currently observed is < 150 dB RMA re 1 [micro]Pa. SPLs of 180 dB may
cause noticeable changes in behavior (Pearson et al. 1992; Skalski et
al. 1992). SPLs of sufficient strength have been known to cause injury
to fish and fish mortality. The most likely impact to fish from survey
activities at the project area would be temporary avoidance of the
area. The duration of fish avoidance of a given area after survey
effort stops is unknown, but a rapid return to normal recruitment,
distribution and behavior is anticipated.
Information on seismic airgun impacts to zooplankton, which
represent an important prey type for mysticetes, is limited. However,
McCauley et al. (2017) reported that experimental exposure to a pulse
from a 150 cui airgun decreased zooplankton abundance when compared
with controls, as measured by sonar and net tows, and caused a two- to
threefold increase in dead adult and larval zooplankton. Although no
adult krill were present, the study found that all larval krill were
killed after air gun passage. Impacts were observed out to the maximum
1.2 km range sampled. The reaction of fish to airguns depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors. While
we agree that some studies have demonstrated that airgun sounds might
affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017), other studies have
shown no or slight reaction to airgun sounds (e.g., Pena et al., 2013;
Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott et al., 2012).
In general, impacts to marine mammal prey are expected to be
limited due to the relatively small temporal and spatial overlap
between the proposed survey and any areas used by marine mammal prey
species. The proposed activities would occur over a relatively short
time period in a given area and would occur over a very small area
relative to the area available as marine mammal habitat in Cook Inlet.
We do not have any information to suggest the proposed survey area
represents a significant feeding area for any marine mammal, and we
believe any impacts to marine mammals due to adverse effects to their
prey would be insignificant due to the limited spatial and temporal
impact of the proposed activities. However, adverse impacts may occur
to a few species of fish and to zooplankton. Packard et al. (1990)
showed that cephalopods were sensitive to particle motion, not sound
pressure, and Mooney et al. (2010) demonstrated that squid statocysts
act as an accelerometer through which particle motion of the sound
field can be detected. Auditory injuries (lesions occurring on the
statocyst sensory hair cells) have been reported upon controlled
exposure to low-frequency sounds, suggesting that cephalopods are
particularly sensitive to low-frequency sound (Andre et al., 2011; Sole
et al., 2013). However, these controlled exposures involved long
exposure to sounds dissimilar to airgun pulses (i.e., 2 hours of
continuous exposure to 1-second sweeps, 50-400 Hz). Behavioral
responses, such as inking and jetting, have also been reported upon
exposure to low-frequency sound (McCauley et al., 2000b; Samson et al.,
2014).
Indirect impacts from spills or leaks could occur through the
contamination of lower-trophic-level prey, which could reduce the
quality and/or quantity of marine mammal prey. In addition, individuals
that consume contaminated prey could experience long-term effects to
health (Geraci and St. Aubin 1990). However, the likelihood of spills
and leaks, as described above, is low. This likelihood, in combination
with Hilcorp's spill plan to reduce the risk of hazardous material
spills, is such that its effect on prey is not considered further in
this document.
Acoustic Habitat--Acoustic habitat is the soundscape--which
encompasses all of the sound present in a particular location and time,
as a whole--when considered from the perspective of the animals
experiencing it. Animals produce sound for, or listen for sounds
produced by, conspecifics
[[Page 12354]]
(communication during feeding, mating, and other social activities),
other animals (finding prey or avoiding predators) and the physical
environment (finding suitable habitats, navigating). Together, sounds
made by animals and the geophysical environment (e.g., produced by
earthquakes, lightning, wind, rain, waves) make up the natural
contributions to the total acoustics of a place. These acoustic
conditions, termed acoustic habitat, are one attribute of an animal's
total habitat.
Soundscapes are also defined by, and acoustic habitat influenced
by, the total contribution of anthropogenic sound. This may include
incidental emissions from sources such as vessel traffic or may be
intentionally introduced to the marine environment for data acquisition
purposes (as in the use of airgun arrays or other sources).
Anthropogenic noise varies widely in its frequency content, duration,
and loudness and these characteristics greatly influence the potential
habitat-mediated effects to marine mammals (please see also the
previous discussion on masking under ``Acoustic Effects''), which may
range from local effects for brief periods of time to chronic effects
over large areas and for long durations. Depending on the extent of
effects to habitat, animals may alter their communications signals
(thereby potentially expending additional energy) or miss acoustic cues
(either conspecific or adventitious). For more detail on these concepts
see, e.g., Barber et al., 2010; Pijanowski et al. 2011; Francis and
Barber 2013; Lillis et al. 2014.
Problems arising from a failure to detect cues are more likely to
occur when noise stimuli are chronic and overlap with biologically
relevant cues used for communication, orientation, and predator/prey
detection (Francis and Barber 2013). Although the signals emitted by
seismic airgun arrays are generally low frequency, they would also
likely be of short duration and transient in any given area due to the
nature of these surveys. Sub-bottom profiler use is also expected to be
short term and not concentrated in one location for an extended period
of time. The activities related to exploratory drilling, while less
transitory in nature, are anticipated to have less severe effects due
to lower source levels and therefore smaller disturbance zones than the
mobile sources considered here. Nonetheless, we acknowledge the general
addition of multiple sound source types into the area, which are
expected to have intermittent impacts on the soundscape, typically of
relatively short duration in any given area.
In summary, activities associated with the proposed action are not
likely to have a permanent, adverse effect on any fish habitat or
populations of fish species or on the quality of acoustic habitat.
Thus, any impacts to marine mammal habitat are not expected to cause
significant or long-term consequences for individual marine mammals or
their populations.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this proposed rule, which will
inform both NMFS' consideration of ``small numbers'' and the negligible
impact determination.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as: Any act of
pursuit, torment, or annoyance which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of seismic survey and construction equipment has the potential to
result in disruption of behavioral patterns for individual marine
mammals. There is also some potential for auditory injury (Level A
harassment) to result from equipment such as seismic airguns, primarily
for mysticetes and high frequency species, because predicted auditory
injury zones are larger than for mid-frequency species and otariids.
Auditory injury is unlikely to occur for mid-frequency cetaceans. The
proposed mitigation and monitoring measures are expected to minimize
the severity of such taking to the extent practicable.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
and the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring results or average group size). Below, we describe the
factors considered here in more detail and present the proposed take
estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed acoustic
thresholds that identify the received level of underwater sound above
which exposed marine mammals would be reasonably expected to experience
behavioral disturbance (equated to Level B harassment) or to incur PTS
of some degree (equated to Level A harassment).
Level B Harassment for non-explosive sources--Though significantly
driven by received level, the onset of behavioral disturbance from
anthropogenic noise exposure is also informed to varying degrees by
other factors related to the source (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on the available science and the practical
need to use a threshold based on a factor that is both predictable and
measurable for most activities, NMFS uses a generalized acoustic
threshold based on received level to estimate the onset of behavioral
disturbance rising to the level of Level B Harassment. NMFS predicts
that marine mammals are likely to experience behavioral disturbance
sufficient to constitute Level B harassment when exposed to underwater
anthropogenic noise above received levels of 120 dB re 1 [mu]Pa (rms)
for continuous (e.g., vibratory pile-driving, drilling) and above 160
dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific sonar) sources.
Hilcorp's proposed activity includes the use of continuous
(vibratory pile driving, water jet) and impulsive (seismic airguns,
sub-bottom profiler, conductor pipe driving, VSP) sources, and
therefore the 120 and 160 dB re 1 [mu]Pa (rms) are applicable.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual
criteria to assess auditory injury
[[Page 12355]]
(Level A harassment) to five different marine mammal groups (based on
hearing sensitivity) as a result of exposure to noise from two
different types of sources (impulsive or non-impulsive). Hilcorp's
proposed activity includes the use of impulsive (seismic airguns, sub-
bottom profiler, conductor pipe driving, VSP) and non-impulsive
(vibratory pile driving, water jet) sources.
These thresholds for PTS are provided in the table below. The
references, analysis, and methodology used in the development of the
thresholds are described in NMFS 2018 Technical Guidance, which may be
accessed at: https://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.
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Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
2D Seismic Survey--The area of ensonification for the 2D seismic
survey was calculated by multiplying the distances (in km) to the NMFS
thresholds (Level A harassment distances from the User spreadsheet and
Level B harassment distances to the 160dB isopleth) on both sides of
the vessel by the distance of the line (in km) to be surveyed each day.
The in-water source line is 6 km in length and only one line will be
surveyed each day. Therefore, the line length surveyed each day for the
2D seismic survey is 6 km.
3D Seismic Survey--The area of ensonification for the 3D seismic
survey was calculated by multiplying the distances (in km) to the NMFS
thresholds by the distance of the line (in km) to be surveyed each day.
The line length is approximately 27.78 km (15 nm), which will take
approximately 3.75 hrs to survey at a vessel speed of
[[Page 12356]]
4 knots (7.5 km/hr) with a turn of 1.5 hrs. In a 24-hr period, assuming
no delays, the survey team will be able to collect data on 4.5 lines or
approximately 127 km. The distance in between line lengths is 3.7 km (2
nm), so there will be overlap of the area of Level B ensonification,
resulting in an overestimation of exposures. Instead, the total daily
area of ensonification was calculated using GIS. The Level B radii were
added to each track line estimated to be traveled in a 24-hour period,
and when there was overlapping areas, the resulting polygons were
merged to one large polygon to eliminate the chance that the areas
could be summed multiple times over the same area. The results of the
overall area are summarized in Table 6 below and shown on Figure 19 in
the application (only showing Level B).
Geohazard Sub-bottom Profiler for Well Sites--The area of
ensonification for the sub-bottom profiler used during the geohazard
surveys for the well sites was calculated by multiplying the distances
(in km) to the NMFS thresholds by the distance of the line (in km) to
be surveyed each day. The maximum required monitoring distance from the
well site per BOEM is 2,400 m (or a total length of 4,800 m in
diameter) and the minimum transect width is 150 m, so the total maximum
number of transects to be surveyed is 32 (4,800 m/150 m). The total
distance to be surveyed is 153.60 km (4.8 km x 32 transects). Assuming
a vessel speed of 4 knots (7.41 km/hr), it will take approximately 0.65
hrs (38 minutes) to survey a single transect of 4.8 km (time =
distance/rate). Assuming the team is surveying for 50 percent of the
day (or 12 hrs), the total number of days it will take to survey the
total survey grid is 7.77 days (0.65 hr x 12 hr). Similar to the 3D
seismic survey, there will be overlap in the Level B ensonification of
the sound because of the distance in between the transects. However,
because the area and grid to be surveyed depends on the results of the
3D survey and the specific location, Hilcorp Alaska proposes to use
this overestimate for purposes of this proposed rulemaking. The total
line length to be surveyed per day is 19.76 km (total distance to be
surveyed 153.6 km/total days 7.77).
Geohazard Sub-bottom Profiler for Pipeline Maintenance--The area of
ensonification for the sub-bottom profiler used during geohazard
surveys for the pipeline maintenance was calculated by multiplying the
distances (in km) to the NMFS thresholds by the distance of the line
(in km) to be surveyed each day. The assumed transect grid is 300 m by
300 m with 150 m transect widths, so the total to be surveyed is 2,400
m (2.4 km). Assuming a vessel speed of 4 knots (7.41 km/hr), it will
take approximately 0.08 hrs (4.86 min) to survey a single transect. The
total number of days it will take to survey the grid is 1 day. Similar
to the 3D seismic survey, there will be overlap of the Level B
ensonification area because of the distance in between the transects.
However, because the area and grid to be surveyed depends on the
results of the 3D survey and the specific location, Hilcorp Alaska
proposes to use this overestimate for purposes of this proposed rule.
The total line length to be surveyed per day is 2.4 km.
Other sources--For stationary sources, area of a circle to the
relevant Level A or Level B harassment isopleths was used to determine
ensonified area. These sources include: Conductor pipe driving, VSP,
vibratory sheet pile driving, and water jets.
When the NMFS Technical Guidance (2016) was published, in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes by Level A
harassment. We note that because of some of the assumptions included in
the methods used for these tools, we anticipate that isopleths produced
are typically going to be overestimates of some degree, which may
result in some degree of overestimate of Level A harassment take.
However, these tools offer the best way to predict appropriate
isopleths when more sophisticated 3D modeling methods are not
available; and NMFS continues to develop ways to quantitatively refine
these tools and will qualitatively address the output where
appropriate. For stationary sources such as conductor pipe driving or
vibratory pile driving, NMFS User Spreadsheet predicts the closest
distance at which, if a marine mammal remained at that distance the
whole duration of the activity, it would not incur PTS. For mobile
sources such as seismic airguns or sub-bottom profilers, the User
Spreadsheet predicts the closest distance at which a stationary animal
would not incur PTS if the sound source traveled by the animal in a
straight line at a constant speed. Inputs used in the User Spreadsheet,
and the resulting isopleths are reported below (Tables 4, 5, and 6).
Transmission loss used for all calculation was practical spreading (15
LogR).
Table 4--NMFS User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Weighting
Activity Type of source Source level factor Source Pulse Repetition rate Duration per day
adjustment velocity duration
--------------------------------------------------------------------------------------------------------------------------------------------------------
2D/3D seismic................ mobile, 217 dB peak @100 1 kHz......... 2.05 m/s...... N/A........ every 6 s............ N/A.
impulsive. m; 185 dB SEL
@100 m.
Sub-bottom profiler.......... mobile, 212 dB rms @1 m. 4 kHz......... 2.05 m/s...... 0.02 s..... every 0.30 s......... N/A.
impulsive.
Pipe driving................. stationary, 195 dB rms @55 m 2 kHz......... N/A........... 0.02 s..... 600 strikes/hr....... 2 hrs/day.
impulsive.
VSP.......................... stationary, 227 dB rms @1m.. 1 kHz......... N/A........... 0.02 s..... Every 6 s............ 4 hrs/day.
impulsive.
Vibratory sheet pile driving. stationary, non- 160 dB rms @10 m 2.5 kHz....... N/A........... N/A........ N/A.................. 4 hrs/day.
impulsive.
Water jet.................... stationary, non- 176 dB rms @1 m. 2 kHz......... N/A........... N/A........ N/A.................. 0.5 hrs/day.
impulsive.
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 12357]]
Table 5--Calculated Distances to NMFS Level A Harassment Thresholds
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Level A
----------------------------------------------------------------------------------------------------------------------------------------------------------
Low frequency cetaceans Mid frequency cetaceans High frequency cetaceans Phocids Otariids
----------------------------------------------------------------------------------------------------------------------------------------------------------
Activity Impulsive Non- Impulsive Non- Impulsive Non- Impulsive Non- Impulsive Non-
------------------ impulsive ------------------ impulsive ------------------ impulsive ------------------ impulsive ------------------ impulsive
219 dB 183 dB ------------- 230 dB 185 dB ------------- 202 dB 155 dB ------------- 218 dB 185 dB ------------- 232 dB 203 dB ------------
pk SEL 199 dB SEL pk SEL 198 dB SEL pk SEL 173 dB SEL pk SEL 201 dB SEL pk SEL 219 dB SEL
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
2D/3D seismic........................ 74 399 ........... 14 <1 ........... 1,000 45 ........... 86 66 ........... 10 1 ...........
Sub-bottom profiler.................. <1 77 ........... <1 4 ........... 5 1,108 ........... <1 48 ........... <1 <1 ...........
Pipe driving......................... 1 134 ........... <1 103 ........... 19 3,435 ........... 2 1,543 ........... <1 112 ...........
VSP.................................. 3 11,217 ........... <1 96 ........... 46 2,617 ........... 4 3,371 ........... <1 249 ...........
Vibratory sheet pile driving......... ....... ....... 15 ....... ....... 1 ....... ....... 22 ....... ....... 9 ....... ....... <1
Water jet............................ ....... ....... 14 ....... ....... <1 ....... ....... 13 ....... ....... 8 ....... ....... 1
Hydraulic grinder.................... ....... ....... 1 ....... ....... <1 ....... ....... 1 ....... ....... <1 ....... ....... <1
Tugs towing.......................... ....... ....... <1 ....... ....... <1 ....... ....... <1 ....... ....... <1 ....... ....... <1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 6--Calculated Distances to NMFS Level B Thresholds
------------------------------------------------------------------------
Level B
-------------------------------------
Activity Impulsive Non-impulsive
-------------------------------------
160 dB rms 120 dB rms
------------------------------------------------------------------------
2D/3D seismic..................... 7,330 .................
Sub-bottom profiler............... 2,929 .................
Pipe driving...................... 1,630 .................
VSP............................... 2,470 .................
Vibratory sheet pile driving...... ................. 4,642
Water jet......................... ................. 5,411
Hydraulic grinder................. <1 398
Tugs towing....................... ................. 2,514
------------------------------------------------------------------------
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
Beluga whale--Historically, beluga whales were observed in both
upper and lower Cook Inlet in June and July (Rugh et al. 2000).
However, between 1993 and 1995, less than 3 percent of all of the
annual sightings were in the lower inlet, south of the East and West
Forelands, hardly any (one whale in Tuxedni Bay in 1997 and two in
Kachemak Bay in 2001) have been seen in the lower inlet during these
surveys 1996-2016 (Rugh et al. 2005; Shelden et al. 2013, 2015, 2017).
Because of the extremely low sighting rates, it is difficult to provide
an accurate estimate of density for beluga whales in the mid and lower
Cook Inlet region.
Goetz et al. (2012b) developed a habitat-based model to estimate
Cook Inlet beluga density based on seasonally collected data. The model
was based on sightings, depth soundings, coastal substrate type,
environmental sensitivity index, anthropogenic disturbance, and
anadromous fish streams to predict densities throughout Cook Inlet. The
result of this work is a beluga density map of Cook Inlet, which
predicts spatially explicit density estimates for Cook Inlet belugas.
Figure 1 shows the Goetz et al. (2012b) estimates with the project
area. Using data from the GIS files provided by NMFS and the different
project locations, the resulting estimated density is shown in Table 7.
The water jets would be used on pipelines throughout the middle Cook
Inlet region, so the higher density for the Trading Bay area was used.
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Densities resulting from this model are summarized in Table 7
below.
Table 7--Cook Inlet Beluga Whale Density Based on Goetz Habitat Model
------------------------------------------------------------------------
Beluga whale density
Project location Project activity (ind/km\2\)
------------------------------------------------------------------------
Lower Cook Inlet (OCS)........ 3D seismic, 0.00
geohazard, pipe
driving.
Lower Cook Inlet (east side).. 2D seismic........ 0.00-0.011106
Iniskin Bay area.............. Sheet pile driving 0.024362
North Cook Inlet Unit......... Geohazard, pipe 0.001664
driving.
Trading Bay area.............. Geohazard, pipe 0.004453-0.015053
driving, water
jets.
------------------------------------------------------------------------
Other Marine Mammals--Density estimates of species other than
beluga whales were estimated from the NMFS June aerial surveys
conducted for beluga whales between 2000 and 2016 (Rugh et al. 2005;
Shelden et al. 2013, 2015, 2017). Although these surveys are only flown
for a few days in one month, they represent the best available
relatively long-term dataset for marine mammal sightings in Cook Inlet.
Table 8 below summarizes the maximum marine mammals observed for each
year for the survey and area covered. To estimate density, the total
number of individuals per species sighted during surveys was divided by
the distance flown on the surveys. The total number of animals observed
accounts for both lower and upper Cook Inlet, so this density estimate
is higher than what is anticipated for the lower Cook Inlet area. There
are no density estimates available for California sea lions for Cook
Inlet so largest potential group size was used.
Table 8--Density Estimates for Marine Mammals in Action Area
------------------------------------------------------------------------
Estimated density
Species (# marine mammals/
km\2\) \3\
------------------------------------------------------------------------
Beluga whale:
Lower and Middle Cook Inlet \1\.................. 0.00006
Lower Cook Inlet \2\............................. 0.01111
North Cook Inlet Unit \2\........................ 0.00166
Trading Bay area \2\............................. 0.01505
Iniskin Peninsula \2\............................ 0.02436
Humpback whale....................................... 0.00009
Minke whale.......................................... 0.00000
Gray whale........................................... 0.00001
Fin whale............................................ 0.00005
Killer whale......................................... 0.00011
Dall's porpoise...................................... 0.00006
Harbor porpoise...................................... 0.00037
Harbor seal.......................................... 0.00655
Steller sea lion..................................... 0.00035
------------------------------------------------------------------------
\1\ NMFS aerial survey combined lower and middle Cook Inlet density.
\2\ Goetz et al. 2012(b) habitat-based model density.
\3\ When using data from NMFS aerial surveys, the survey year with the
greatest calculated density was used to calculate exposures.
No density available for California sea lions in Cook Inlet.
Duration
The duration was estimated for each activity and location. For some
projects, like the 3D seismic survey, the design of the project is well
developed; therefore, the duration is well-defined. However, for some
projects, the duration is not well developed, such as activities around
the lower Cook Inlet well sites, because the duration depends on the
results of previous studies and equipment availability. Our assumptions
regarding these activities, which were used to estimate duration, are
discussed below.
2D Seismic--A single vessel is capable of acquiring a source line
in approximately 1-2 hrs and only one source line will be collected in
one day to allow for all the node deployments and retrievals, and
intertidal and land zone shot holes drilling. There are up to 10 source
lines, so assuming all operations run smoothly, there will only be 2
hrs per day over 10 days of airgun activity. The duration that was used
to assess exposures from the 2D seismic survey is 10 days.
3D Seismic--The total anticipated duration of the survey is 45-60
days, including delays due to equipment, weather, tides, and marine
mammal shut downs. The duration that was used to assess exposures from
the 3D seismic survey is 60 days.
Geohazard Surveys (Sub-bottom profiler)--Assuming surveying occurs
50 percent of the day (or 12 hrs), the total number of days it will
take to survey the total geohazard survey grid for a single well is
7.77 days. This duration was multiplied by the number of wells per site
resulting in 31.1 days for the four Lower Cook Inlet OCS wells, 7.7
days for the North Cook Inlet Unit well, and 15.5 days for the two
Trading Bay area wells.
The total number of days it will take to survey the geohazard
survey grid for a pipeline maintenance is 1 day. This duration was
multiplied by the number of anticipated surveys per year (high estimate
of 3 per year), for a total of 3 days.
Drive Pipe--It takes approximately 3 days to install the drive pipe
per well with only 25 percent of the day necessary for actual pipe
driving. This duration was multiplied by the number
[[Page 12360]]
of wells per site resulting in 3 days for the four lower Cook Inlet
wells and 1.5 days for the two Trading Bay area wells. Drive pipe
installation is not part of the activities planned at the North Cook
Inlet site.
VSP--It takes approximately 2 days to perform the VSP per well with
only 25 percent of the day necessary for actual seismic work. VSP is
not part of the plugging and abandonment (P&A) activities at the North
Cook Inlet site. This duration was multiplied by the number of wells
per site, resulting in 2 days for the four lower Cook Inlet wells and 1
day for the two Trading Bay area wells.
Vibratory Sheet Pile Driving--The total number of days expected to
install the sheet pile dock face using vibratory hammers on the rock
causeway is 14 days with only 25 percent of the day for actual pile
driving, resulting in 3.5 days of sound for the Iniskin project.
Water jets--Water jets are only used when needed for maintenance;
therefore, the annual duration was estimated to evaluate exposures.
Each water jet event was estimated to be 30 minutes or less in
duration. We acknowledge that due to the short duration of this
activity, it is possible that take will not occur--however, we are
including consideration of potential take to conservatively ensure
coverage for the applicant. It was estimated that a water jet event
occurs 3 times a month, resulting in only 1.5 hrs per month of water
jet operation. Water jets are used during ice-free months, so this
duration was multiplied by 7 months (May-November) resulting in 10.5
days.
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate. The numbers of each
marine mammal species that could potentially be exposed to sounds
associated with the proposed activities that exceed NMFS' acoustic
Level A and B harassment criteria were estimated per type of activity
and per location. The specific years when these activities might occur
are not known at this time, so this method of per activity per location
allows for flexibility in operations and provides NMFS with appropriate
information for assessing potential exposures. Individual animals may
be exposed to received levels above our harassment thresholds more than
once per day, but NMFS considers animals only ``taken'' once per day.
Exposures refer to any instance in which an animal is exposed to sound
sources above NMFS' Level A or Level B harassment thresholds. The
estimated exposures (without any mitigation) per activity per location
were calculated by multiplying the density of marine mammals (# of
marine mammals/km\2\) by the area of ensonification (km\2\) and the
duration (days per year). These results of these calculations are
presented in Tables 9 and 10 below.
Table 9--Estimated Number of Level A Exposures per Activity and Location
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3D 2D Iniskin Sub-bottom profiler Pipe driving Vertical seismic
seismic seismic vibratory ------------------------------------------------------------------ profiling
---------------------- sheet Water ---------------------
Species pile jets \6\
LCI \1\ LCI \1\ ----------- MCI \4\ LCI \1\ NCI \2\ TB \3\ LCI \1\ TB \3\ LCI \1\ TB \3\
LCI \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale.............................................. 6.80 0.05 0.00 0.00 0.00 0.09 0.02 0.04 0.00 0.00 5.97 2.98
Minke whale................................................. 0.04 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.02
Gray whale.................................................. 0.29 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.25 0.13
Fin whale................................................... 1.19 0.01 0.00 0.00 0.00 0.02 0.00 0.01 0.00 0.00 1.05 0.52
Killer whale................................................ 0.07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Beluga whale................................................ 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.00
Dall's porpoise............................................. 1.31 0.01 0.00 0.00 0.00 0.11 0.03 0.06 0.00 0.00 0.03 0.01
Harbor porpoise............................................. 37.25 0.29 0.00 0.00 0.04 3.20 0.80 1.60 0.00 0.00 0.81 0.40
Harbor seal................................................. 287.11 2.26 0.00 0.00 0.09 7.39 1.85 3.69 0.05 0.02 5.80 2.90
Steller sea lion............................................ 0.70 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ LCI--Lower Cook Inlet Wells, \2\ NCI--North Cook Inlet Unit well, \3\ TB = Trading Bay wells, \4\ MCI--Middle Cook Inlet Pipeline Maintenance.
Table 10--Estimated Number of Level B Exposures per Activity and Location
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3D 2D Iniskin Sub-bottom profiler Pipe driving Vertical seismic
seismic seismic vibratory ------------------------------------------------------------------ profiling
---------------------- sheet Water ---------------------
Species pile jets \6\
LCI \1\ LCI \1\ ----------- MCI \4\ LCI \1\ NCI \2\ TB \3\ LCI \1\ TB \3\ LCI \1\ TB \3\
LCI \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale.............................................. 85.43 0.83 0.64 0.01 0.04 3.40 0.85 1.70 0.05 0.02 0.07 0.04
Minke whale................................................. 0.45 0.00 0.00 0.00 0.00 0.02 0.00 0.01 0.00 0.00 0.00 0.04
Gray whale.................................................. 3.60 0.04 0.03 0.00 0.00 0.14 0.04 0.07 0.00 0.00 0.00 0.04
Fin whale................................................... 14.99 0.15 0.11 0.00 0.01 0.60 0.15 0.30 0.01 0.00 0.01 0.04
Killer whale................................................ 29.02 0.28 0.22 0.00 0.01 1.15 0.29 0.58 0.02 0.01 0.02 0.04
Beluga whale................................................ 0.00 0.00 8.24 0.05 0.00 0.00 0.75 13.54 0.00 0.19 0.00 0.04
Dall's porpoise............................................. 7.42 0.07 0.06 0.00 0.00 0.30 0.07 0.15 0.00 0.00 0.01 0.04
Harbor porpoise............................................. 211.70 2.06 1.58 0.02 0.10 8.42 2.10 4.21 0.12 0.06 0.18 0.04
Harbor seal................................................. 11,255.01 109.38 84.17 0.83 5.24 447.52 111.88 223.76 6.23 3.11 9.53 0.04
Steller sea lion............................................ 366.99 3.57 2.74 0.03 0.17 14.59 3.65 7.30 0.20 0.10 0.31 0.04
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ LCI--Lower Cook Inlet Wells, \2\ NCI--North Cook Inlet Unit well, \3\ TB = Trading Bay wells, \4\ MCI--Middle Cook Inlet Pipeline Maintenance.
The take estimates by activity and location discussed in the
previous section are not representative of the estimated takes 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, the applicant will submit an application for an LOA
with the specific details of the planned work for that year with
estimated take numbers. The most realistic scenario used to estimate
annual takes includes 3D seismic surveys in the first season,
activities for one well in the second season in lower Cook Inlet, as
well as the plugging and abandonment activities in North Cook Inlet
Unit and the two wells in the Trading Bay area. For the third season,
we have included activities for drilling
[[Page 12361]]
two wells in lower Cook Inlet and the final well in the fourth season.
Table 17 summarizes the activities included in this second scenario.
Table 11--Summary of Activities Considered by Year
------------------------------------------------------------------------
Year Activity Area
------------------------------------------------------------------------
May 2019-2020................. 3D seismic....... LCI.
Geohazard........ LCI.
Sheet pile Iniskin (LCI).
driving.
Pipeline MCI.
maintenance
(geohazard,
water jet,
grinder).
April 2020-2021............... Drilling LCI.
activities
(tugs,
geohazard, pipe
driving, VSP) at
all 1 well.
Drilling TB.
activities
(tugs,
geohazard, pipe
driving, VSP) at
2 wells.
P&A activities NCI.
(tugs,
geohazard) at 1
well.
Pipeline MCI
maintenance
(geohazard,
water jet,
grinder).
April 2021-2022............... Drilling LCI.
activities
(tugs,
geohazard, pipe
driving, VSP) at
2wells.
2D seismic....... LCI.
Pipeline MCI.
maintenance
(geohazard,
water jet,
grinder).
April 2022-2023............... Drilling LCI.
activities
(tugs,
geohazard, pipe
driving, VSP) at
1 well.
Pipeline MCI.
maintenance
(geohazard,
water jet,
grinder).
April 2023-2024............... Pipeline MCI.
maintenance
(geohazard,
water jet,
grinder).
------------------------------------------------------------------------
LCI--Lower Cook Inlet Wells, NCI--North Cook Inlet Unit well, TB =
Trading Bay wells, MCI--Middle Cook Inlet Pipeline Maintenance.
Table 12--Estimated Exposures for First Year of Activity
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Level A Level B
-------------------------------------------------------------------------------------------------------------------------------------
Species MCI MCI LCI sub- LCI sheet MCI MCI LCI sub- LCI sheet
pipeline pipeline LCI 3D bottom pile Total pipeline pipeline LCI 3D bottom pile Total
geohazard water jet seismic profiler driving geohazard water jet seismic profiler driving
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale............................................ 0 0 6.8 0.09 0 6.89 0.04 0.15 85.43 3.4 2.56 91.57
Minke whale............................................... 0 0 0.04 0 0 0.04 0 0 0.45 0.02 0.01 0.48
Gray whale................................................ 0 0 0.29 0 0 0.29 0 0.01 3.60 0.14 0.11 3.86
Fin whale................................................. 0 0 0.29 0.02 0 0.31 0.01 0.03 3.60 0.60 0.45 4.68
Killer whale.............................................. 0 0 1.19 0 0 1.19 0.01 0.05 14.99 1.15 0.87 17.08
Beluga whale.............................................. 0 0 0 0 0 0 0 1.2 0 0 32.98 34.18
Dall's porpoise........................................... 0 0 1.31 0.11 0 1.42 0 0.01 7.42 0.3 0.22 7.95
Harbor porpoise........................................... 0.04 0 37.25 3.2 0 40.49 0.1 0.37 211.70 8.42 6.33 226.92
Harbor seal............................................... 0.09 0 287.11 7.39 0 294.58 5.24 19.85 11255.01 447.52 336.67 12064.29
Steller sea lion.......................................... 0 0 0.7 0 0 0.7 0.17 0.65 366.99 14.59 10.98 393.38
California sea lion....................................... 0 0 0 0 0 0 0 0 0 0 0 0
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 13--Estimated Exposures for Second Year of Activity
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Level A Level B
---------------------------------------------------- ----------------------------------------------------
LCI LCI
geohazard, geohazard,
MCI MCI pipe MCI MCI pipe
pipeline pipeline driving, pipeline pipeline driving,
geohazard water jet VSP (1 well geohazard water jet VSP (1 well
only) only)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale................................................ 0 0 1.51 ........... ........... 0.04 0.15 0.97 ........... ...........
Minke whale................................................... 0 0 0.01 ........... ........... 0 0 0.01 ........... ...........
Gray whale.................................................... 0 0 0.06 ........... ........... 0 0.01 0.04 ........... ...........
Fin whale..................................................... 0 0 0.27 ........... ........... 0.01 0.03 0.17 ........... ...........
Killer whale.................................................. 0 0 0 ........... ........... 0.01 0.05 0.33 ........... ...........
Beluga whale.................................................. 0 0 0 ........... ........... 0 1.2 0 ........... ...........
Dall's porpoise............................................... 0 0 0.04 ........... ........... 0 0.01 0.08 ........... ...........
Harbor porpoise............................................... 0.04 0 1 ........... ........... 0.10 0.37 2.4 ........... ...........
Harbor seal................................................... 0.09 0 3.31 ........... ........... 5.24 19.85 127.64 ........... ...........
Steller sea lion.............................................. 0 0 0 ........... ........... 0.17 0.65 4.16 ........... ...........
California sea lion........................................... 0 0 0 ........... ........... 0 0 0 ........... ...........
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Level A Subtotal Subtotal
for all for all
activities Level B activities
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
NCI TB TB pipe TB VSP NCI TB TB pipe TB VSP
geohazard geohazard driving geohazard geohazard driving
(1 well) (2 wells) (2 wells) (1 well) (2 wells) (2 wells)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale................................................ .02 .04 0 2.98 4.57 0.85 1.7 0.09 0.14 3.95
Minke whale................................................... 0 0 0 0.02 0.02 0 0.01 0 0 0.02
Gray whale.................................................... 0 0 0 0.13 0.19 0.04 0.07 0 0.01 0.17
Fin whale..................................................... 0 0.01 0 0.52 0.8 0.15 0.3 0.02 0.03 0.69
Killer whale.................................................. 0 0 0 0 0 0.85 0.58 0.03 0.05 1.9
Beluga whale.................................................. 0.02 0.02 0 0 0.04 0.85 13.54 0.75 1.15 17.5
[[Page 12362]]
Dall's porpoise............................................... 0.02 0.06 0 0.01 0.13 0.85 0.15 0.01 0.01 1.12
Harbor porpoise............................................... 0.02 1.6 0 0.4 3.07 0.85 4.21 0.23 0.36 8.52
Harbor seal................................................... 0.02 3.69 0.02 2.9 10.04 0.85 223.76 12.46 19.07 408.87
Steller sea lion.............................................. 0.02 0 0 0.01 0.03 0.85 7.3 0.41 0.62 14.15
California sea lion........................................... 0 0 0 0 0 0 0 0 0 0
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 14--Estimated Exposures for Third Year of Activity
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Level A Level B
---------------------------------------------------- ----------------------------------------------------
LCI LCI
geohazard, geohazard,
MCI MCI pipe LCI 2D Total MCI MCI pipe LCI 2D Total
pipeline pipeline driving, seismic pipeline pipeline driving, seismic
geohazard water jet VSP (2 geohazard water jet VSP (2
wells only) wells only)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale................................................ 0 0 3.03 0.05 3.08 0.04 0.15 1.94 0.83 2.96
Minke whale................................................... 0 0 0.02 0 0.02 0 0 0.01 0 0.02
Gray whale.................................................... 0 0 0.13 0 0.13 0 0.01 0.08 0.04 0.12
Fin whale..................................................... 0 0 0.53 0.01 0.54 0.01 0.03 0.34 0.15 0.52
Killer whale.................................................. 0 0 0 0 0 0.01 0.05 0.66 0.28 1.01
Beluga whale.................................................. 0 0 0 0.01 0.01 0 1.2 0 4.8 6.09
Dall's porpoise............................................... 0 0 0.07 0.01 0.08 0 0.01 0.17 0.07 0.26
Harbor porpoise............................................... 0.04 0 2 0.29 2.34 0.1 0.37 4.8 2.06 7.33
Harbor seal................................................... 0.09 0 6.62 2.26 8.97 5.24 19.85 255.28 109.38 389.76
Steller sea lion.............................................. 0 0 0.01 0.01 0.01 0.17 0.65 8.32 3.57 12.71
California sea lion........................................... 0 0 0 0 0 0 0 0 0 0
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 15--Estimated Exposures for Fourth Year of Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A Level B
--------------------------------------- ---------------------------------------
LCI LCI
geohazard, geohazard,
MCI MCI pipe Total MCI MCI pipe Total
pipeline pipeline driving, pipeline pipeline driving,
geohazard water jet VSP (1 well geohazard water jet VSP (1 well
only) only)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale.................................. 0 0 1.51 1.52 0.04 0.15 0.97 1.16
Minke whale..................................... 0 0 0.01 0.01 0 0 0.01 0.01
Gray whale...................................... 0 0 0.06 0.06 0 0.01 0.04 0.05
Fin whale....................................... 0 0 0.27 0.27 0.01 0.03 0.17 0.2
Killer whale.................................... 0 0 0 0 0.01 0.05 0.33 0.39
Beluga whale.................................... 0 0 0 0 0 1.2 0 1.2
Dall's porpoise................................. 0 0 0.04 0.04 0 0.01 0.08 0.10
Harbor porpoise................................. 0.04 0 1 1.04 0.1 0.37 2.40 2.87
Harbor seal..................................... 0.09 0 3.31 3.40 5.24 19.85 127.64 152.74
Steller sea lion................................ 0 0 0 0 0.17 0.65 4.16 4.98
California sea lion............................. 0 0 0 0 0 0 0 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 16--Estimated Exposures for Fifth Year of Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A Level B
-----------------------------------------------------------------------------------------------
MCI pipeline MCI pipeline MCI pipeline MCI pipeline
geohazard water jet Total geohazard water jet Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale.......................................... 0 0 0 0.04 0.15 0.19
Minke whale............................................. 0 0 0 0 0 0
Gray whale.............................................. 0 0 0 0 0.01 0.01
Fin whale............................................... 0 0 0 0.01 0.03 0.03
Killer whale............................................ 0 0 0 0.01 0.05 0.06
Beluga whale............................................ 0 0 0 0 1.2 1.2
Dall's porpoise......................................... 0 0 0 0 0.01 0.02
6.09+Harbor porpoise.................................... 0.04 0 0.04 0.1 0.37 0.47
Harbor seal............................................. 0.09 0 0.09 5.24 19.85 25.10
Steller sea lion........................................ 0 0 0 0.17 0.65 0.82
California sea lion..................................... 0 0 0 0 0 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 12363]]
Table 17--Estimated Maximum Exposures That May Be Authorized in One Year, Based on First Year of Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A Level B
---------------------------------------------------------------------------------------------------------------
Species Total Total Percent of Total Total
calculated authorized stock calculated authorized Percent of stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale.......................... 6.89 7 0.63 91.57 92 8.31
Minke whale............................. 0.04 0 0 0.48 1 0.08
Gray whale.............................. 0.29 0 0 3.86 4 0.02
Fin whale............................... 0.31 0 0 4.68 5 0.16
Killer whale............................ 1.19 0 0 17.08 17 0.72 (resident) or 2.90
(transient)
Beluga whale............................ 0 0 0 34.18 30 9.62
Dall's porpoise......................... 1.42 2 0.0024 7.95 8 0.01
Harbor porpoise......................... 40.49 40 0.13 226.92 227 0.73
Harbor seal............................. 294.58 295 1.1 12064.29 6,000 21.91
Steller sea lion........................ 0.7 1 0 393.38 394 0.74
California sea lion..................... 0 0 0 0 5 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 18--Total Exposures Calculated and Requested Over the 5-year Regulations
----------------------------------------------------------------------------------------------------------------
Calculated Exposures Authorized Exposures
Group Species ---------------------------------------------------------------
Level A Level B Level A Level B
----------------------------------------------------------------------------------------------------------------
LF Cetaceans.................. Humpback whale.. 16.06 99.82 16 100
Minke whale..... 0.08 0.53 0 5
Gray whale...... 0.68 4.21 0 5
Fin whale....... 1.91 6.93 0 7
MF Cetaceans.................. Killer whale.... 0.2 20.44 0 20
Beluga whale.... 0.05 60.17 0 35
HF Cetaceans.................. Dall's porpoise. 1.67 9.45 5 10
Harbor porpoise. 46.97 246.12 47 246
Phocids....................... Harbor seal..... 317.07 13040.77 317 6847
Otariids...................... Steller sea lion 0.76 426.04 5 426
California sea 0 0 0 5
lion.
----------------------------------------------------------------------------------------------------------------
Based on the results of the acoustic harassment analysis, Hilcorp
Alaska is requesting a small number of takes by Level A harassment for
humpback whales, Dall's porpoises, harbor porpoises, Steller sea lions,
and harbor seals. Hilcorp Alaska does not anticipate that any of the
activities will result in mortality or serious injury to marine
mammals, but these species may be exposed to levels exceeding the Level
A harassment thresholds. Seals are highly curious and exhibit high
tolerance for anthropogenic activity, so they are likely to enter
within the larger Level A harassment isopleths. Porpoises are difficult
to observer at greater distances and usually only remain in an area for
a short period of time. The total requested takes by Level A harassment
are for 16 humpback whales, 5 Dall's porpoises, 47 harbor porpoises,
and 317 harbor seals. Note this is not a request for annual takes, but
total takes over the 5-year period.
The requested takes by Level B harassment for minke and gray whale
are rounded up to 5 animals, based on the assumption that one could be
taken per year for five years. The requested takes by Level B
harassment for humpback whales is 100 animals, although it is not
expected to approach this number as humpbacks are easily observable
during monitoring efforts. The requested takes by Level B harassment
for killer whales are rounded up to 20 animals to allow for small
groups. The requested takes by Level B harassment for Dall's and harbor
porpoise are rounded up to 10 and 246 animals, respectively, due to the
inconspicuous nature of porpoises.
The requested takes by Level B harassment for harbor seals is 6,847
animals. The estimated number of instances of takes by Level B
harassment of 13,041 resulting from the calculations outlined above is
an overestimate due to the inclusion of haul out sites numbers in the
underlying density estimate used to calculate take. Using the daily
ensonified area x number of survey days x density method results in a
reasonable estimate of the instances of take, but likely significantly
overestimates the number of individual animals expected to be taken.
With most species, even this overestimated number is still very small,
and additional analysis is not really necessary to ensure minor
impacts. However, because of the number and density of harbor seals in
the area, a more accurate understanding of the number of individuals
likely taken is necessary to fully analyze the impacts and ensure that
the total number of harbor seals taken is small.
As described below, based on monitoring results from the area, it
is likely that the modeled number of estimated instances of harbor seal
take referenced above is overestimated. The density estimate from NMFS
aerial surveys includes harbor seal haulouts far south of the action
area that may never move to an ensonified area. Further, we believe
that we can reasonably estimate the comparative number of individual
harbor seals that will likely be taken, based both on monitoring data,
operational information, and a general understanding of harbor seal
habitat use.
Using the daily ensonified area x number of survey days x density,
the number of instances of exposure above the 160-dB threshold
estimated for Hilcorp's activity in Cook Inlet is large.
[[Page 12364]]
However, when we examine monitoring data from previous activities, it
is clear this number is an overestimate--compared to both aerial and
vessel based observation efforts. Apache's monitoring report from 2012
details that they saw 2,474 harbor seals from 29 aerial flights (over
29 days) in the vicinity of the survey during the month of June, which
is the peak month for harbor seal haulout. In surveying the literature,
correction factors to account for harbor seals in water based on land
counts vary from 1.2 to 1.65 (Harvey & Goley, 2011). Using the most
conservative factor of 1.65 (allowing us to consider that some of the
other individuals on land may have entered the water at other points in
day), if Apache saw 2,474 seals hauled out then there were an estimated
1,500 seals in the water during those 29 days. To account for the
limited number of surveys (29 surveys), NMFS conservatively multiplied
the number of seals by 5.5 to estimate the number of seals that might
have been seen if the aerial surveys were conducted for 160 days. This
yields an estimate of 8,250 instances of seal exposure in the water,
which is far less than the exposure estimate resulting from Hilcorp's
calculations. NMFS further reduced the estimate given the context of
the activity. The activity with the highest potential take of harbor
seal according to calculations is 3D seismic surveying, primarily due
to the high source levels. However, the 3D seismic surveying is
occurring primarily offshore, which is also the area where they are
least likely to encounter harbor seals. The calculated exposures from
3D seismic surveying account for 92 percent of the total calculated
harbor seal exposures across the five years of the project, accounting
for a high proportion of the takes allocated to deeper water seismic
activity which is less likely to spatially overlap with harbor seals.
That the number of potential instances of exposure is likely less than
calculated is also supported by the visual observations from Protected
Species Observers (PSOs) on board vessels. PSOs in Cook Inlet sighted a
total of 285 seals in water over 147 days of activity, which would rise
to about 310 if adjusted to reflect 160 days of effort. Given the size
of the disturbance zone for these activities, it is likely that not all
harbor seals that were exposed were seen by PSOs. However 310 is still
far less than the estimate given by the density calculations.
Further, based on the residential nature of harbor seals and the
number of offshore locations included in Hilcorp's project, where
harbor seals are unlikely to reside, NMFS estimated the number of
individual harbor seals exposed, given the instances of exposures.
Given these multiple methods, as well as the behavioral preferences of
harbor seals for haulouts in certain parts of the Inlet (Montgomery et
al., 2007), and high concentrations at haulouts in the lower Inlet, it
is unreasonable to expect that more than 25 percent of the population,
or 6,847 individuals, will be taken by Level B harassment during
Hilcorp's activity. Therefore, we estimate that 6,847 individuals are
taken, which equates to 25 percent of the estimated abundance in NMFS
stock assessment report.
Effects of Specified Activities on Subsistence Uses of Marine Mammals
The availability of the affected marine mammal stocks or species
for subsistence uses may be impacted by this activity. The subsistence
uses that may be affected and the potential impacts of the activity on
those uses are described below. Measures included in this proposed rule
to reduce the impacts of the activity on subsistence uses are described
in the Proposed Mitigation section. Last, the information from this
section and the Proposed Mitigation section is analyzed to determine
whether the necessary findings may be made in the Unmitigable Adverse
Impact Analysis and Determination section.
The ADF&G conducted studies to document the harvest and use of wild
resources by residents of communities on the east and west sides of
Cook Inlet (Jones and Kostick 2016). Data on wild resource harvest and
use were collected, including basic information about who, what, when,
where, how, and how much wild resources are being used to develop
fishing and hunting opportunities for Alaska residents. Tyonek was
surveyed in 2013 (Jones et al., 2015), and Nanwalek, Port Graham, and
Seldovia were surveyed in 2014 (Jones and Kostick 2016). Marine mammals
were harvested by three (Seldovia, Nanwalek, Port Graham) of the four
communities but at relatively low rates. The harvests consisted of
harbor seals, Steller sea lions, and northern sea otters (Enhydra
lutris), the latter of which is managed by the U.S. Fish and Wildlife
Service and not mentioned further.
Table 19--Marine Mammal Harvest by Tyonek in 2013 and Nikiski, Port Graham, Seldovia, and Nanwalek in 2014
--------------------------------------------------------------------------------------------------------------------------------------------------------
Households Number of marine mammals harvested
Harvest attempting ---------------------------------------------------------------
Village (pounds per harvest number
capita) (% of Harbor seal Steller sea Northern sea Beluga whale
residents) lion otter
--------------------------------------------------------------------------------------------------------------------------------------------------------
Tyonek.................................................. 2 6 (6%) 6 0 0 0
Seldovia................................................ 1 2 (1%) 5 0 3 0
Nanwalek................................................ 11 17 (7%) 22 6 1 0
Port.................................................... 8 27 (18%) 16 1 24 0
Graham..................................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
In Tyonek, harbor seals were harvested between June and September
by 6 percent of the households (Jones et al. 2015). Seals were
harvested in several areas, encompassing an area stretching 20 miles
along the Cook Inlet coastline from the McArthur River Flats north to
the Beluga River. Seals were searched for or harvested in the Trading
Bay areas as well as from the beach adjacent to Tyonek (Jones et al.
2015). In Seldovia, the harvest of harbor seals (5 total) occurred
exclusively in December (Jones and Kostick 2016).
In Nanwalek, 22 harbor seals were harvested in 2014 between March
and October, the majority of which occur in April. Nanwalek residents
typically hunt harbor seals and Steller sea lions at Bear Cove, China
Poot Bay, Tutka Bay, Seldovia Bay, Koyuktolik Bay, Port Chatam, in
waters south of Yukon Island, and along the shorelines close to
[[Page 12365]]
Nanwalek, all south of the Petition region (Jones and Kosick 2016).
According to the results presented in Jones and Kostick (2016) in
Port Graham, harbor seals were the most frequently used marine mammal;
tribal members harvested 16 in the survey year. Harbor seals were
harvested in January, February, July, August, September, November, and
December. Steller sea lions were used noticeably less and harvested in
November and December.
The Cook Inlet beluga whale has traditionally been hunted by Alaska
Natives for subsistence purposes. For several decades prior to the
1980s, the Native Village of Tyonek residents were the primary
subsistence hunters of Cook Inlet beluga whales. During the 1980s and
1990s, Alaska Natives from villages in the western, northwestern, and
North Slope regions of Alaska either moved to or visited the south-
central region and participated in the yearly subsistence harvest
(Stanek 1994). From 1994 to 1998, NMFS estimated 65 whales per year
were taken in this harvest, including those successfully taken for
food, and those struck and lost. NMFS has concluded that this number is
high enough to account for the estimated 14 percent annual decline in
population during this time (Hobbs et al. 2008). Actual mortality may
have been higher, given the difficulty of estimating the number of
whales struck and lost during the hunts. In 1999, a moratorium was
enacted (Pub. L. 106-31) prohibiting the subsistence take of Cook Inlet
beluga whales except through a cooperative agreement between NMFS and
the affected Alaska Native organizations.
On October 15, 2008, NMFS published a final rule that established
long-term harvest limits on the Cook Inlet beluga whales that may be
taken by Alaska Natives for subsistence purposes (73 FR 60976). That
rule prohibits harvest for a 5-year period (2008-2012), if the average
abundance for the Cook Inlet beluga whales from the prior five years
(2003-2007) is below 350 whales. The next 5-year period that could
allow for a harvest (2013-2017) would require the previous five-year
average (2008-2012) to be above 350 whales. Since the Cook Inlet beluga
whale harvest was regulated in 1999 requiring cooperative agreements,
five beluga whales have been struck and harvested. Those beluga whales
were harvested in 2001 (one animal), 2002 (one animal), 2003 (one
animal), and 2005 (two animals). The Native Village of Tyonek agreed
not to hunt or request a hunt in 2007, when no co-management agreement
was to be signed (NMFS 2008).
The 2008 Cook Inlet Beluga Whale Subsistence Harvest Final
Supplemental Environmental Impact Statement (NMFS 2008a) authorizes how
many beluga whales can be taken during a 5-year interval based on the
5-year population estimates and 10-year measure of the population
growth rate. Based on the 2008-2012 5-year abundance estimates, no hunt
occurred between 2008 and 2012 (NMFS 2008a). The Cook Inlet Marine
Mammal Council, which managed the Alaska Native Subsistence fishery
with NMFS, was disbanded by a unanimous vote of the Tribes'
representatives on June 20, 2012. No harvest has occurred since then
and no harvest is likely in 2018.
Residents of the Native Village of Tyonek are the primary
subsistence users in Knik Arm area (73 FR 60976). No households hunted
beluga whale locally in Cook Inlet due to conservation concerns (Jones
et al. 2015). The proposed project should not have any effect because
no beluga harvest has taken place since 2005, and beluga hunts are not
expected during the next five-year period.
Proposed Mitigation
In order to issue an LOA under section 101(a)(5)(A) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to such
activity, and other means of effecting the least practicable impact on
such species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting such activity or other means of effecting the
least practicable adverse impact upon the affected species or stocks
and their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, we
carefully consider two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure will be effective if
implemented (probability of accomplishing the mitigating result if
implemented as planned), the likelihood of effective implementation
(probability implemented as planned) and;
(2) the practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
Mitigation for Marine Mammals and Their Habitat
Hilcorp has reviewed mitigation measures employed during seismic
research surveys authorized by NMFS under previous incidental
harassment authorizations, as well as recommended best practices in
Richardson et al. (1995), Pierson et al. (1998), Weir and Dolman
(2007), Nowacek et al. (2013), Wright (2014), and Wright and Cosentino
(2015), and has incorporated a suite of proposed mitigation measures
into their project description based on the above sources.
To reduce the potential for disturbance from acoustic stimuli
associated with the activities, Hilcorp has proposed to implement the
following mitigation measures for marine mammals:
(1) Vessel-based and shore-based visual mitigation monitoring;
(2) Establishment of a marine mammal exclusion zone (EZ) and safety
zone (SZ);
(3) Shutdown procedures;
(4) Power down procedures;
(5) Ramp-up procedures; and
(6) Vessel strike avoidance measures.
In addition to the measures proposed by Hilcorp, NMFS has proposed
the following mitigation measures: Aerial overflights for pre-clearance
and seasonal closure of the Susitna River Delta.
Exclusion and safety zones--The Exclusion Zone (EZ) is defined as
the area in which all operations are shut down in the event a marine
mammal enters or is about to enter this zone based on distances to the
Level A harassment threshold or what can be effectively monitored for
the species. The Safety Zone (SZ) is an area larger than the EZ and is
defined as the area within which operations may power down in the event
a marine mammal enters or is about to enter, and may be considered a
Level B harassment. For all activities, if a marine mammal for which
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take is not authorized is seen within or entering the SZ, operations
will shut down. A minimum 10 meter shutdown zone will be observed for
all in-water construction and heavy machinery.
The distances for the EZ and SZ for the activities are summarized
in Table 20 and described in the following text:
(1) The distances to the Level A harassment thresholds for the 2D/
3D seismic activity were calculated using the methods described above
and are indicated in Table 5 above. As in several recent IHAs
authorizing take from seismic surveys (e.g., five surveys in the
Atlantic (82 FR 26244) and NSF (83 FR 44578)), we have proposed a more
standardized 500-m EZ, which is practicable to implement and minimizes
the likelihood of injury or more severe behavioral responses. The SZ
for all marine mammals is 1,000 m. The distances to the thresholds for
the sub-bottom profiler were calculated using the methods described
above. The EZ for all marine mammals is rounded up to 100 m.
(2) The distances to the Level A harassment thresholds for the pipe
driving were calculated using methods above and the distance to the
Level B harassment threshold is based on Illingworth & Rodkin (2014)
measurements of 1,600 m to the 160 dB zone. The EZ for all marine
mammals is rounded up to 100 m. The SZ for all marine mammals is 1,600
m.
(3) The distances to the Level A harassment thresholds for VSP were
calculated using methods described in above and the distance to the
Level B harassment threshold is based on Illingworth & Rodkin (2014)
measurements of 2,470 m to the 160 dB zone. The EZ for all marine
mammals is 500 m.
(4) The distances to the Level A and B harassment thresholds for
the vibratory sheet pile driving were calculated using the methods
described above. The EZ for all marine mammals is 100 m. The SZ for all
marine mammals is 2,500 m.
(5) The distances to the Level A harassment thresholds for the
water jet were calculated using methods described above and the
distance to the Level B harassment threshold is based on Austin (2017)
measurements of 860 m to the 120 dB zone. The EZ for all marine mammals
is rounded up to 15 m. The SZ for all marine mammals is 860 m.
(6) NMFS proposes that Hilcorp shut down if a beluga is observed
within or entering the EZ or SZ for seismic airgun or sub-bottom
profiler use.
Table 20--Radii of Exclusion Zone (EZ) and Safety Zone (SZ) for
Hilcorp's Activities
------------------------------------------------------------------------
Exclusion zone Safety zone
Activity (EZ) radius (SZ) radius
(m) (m)
------------------------------------------------------------------------
2D/3D seismic survey.................... 500 1,000
Sub-bottom profilers.................... 100 1,000
Pipe driving............................ 100 1,600
VSP..................................... 500 2,500
Sheet pile driving...................... 100 2,500
Water jet............................... 15 860
------------------------------------------------------------------------
PSO Placement--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 VSP, 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.
Seismic and Geohazard Survey Mitigation
Aircraft (Seismic only)--NMFS proposes to require aerial
overflights to clear the intended area of seismic survey activity of
beluga whales on a daily basis. Hilcorp will fly over the action area
searching for belugas prior to ramp up of seismic airguns and ramp up
will not commence until the flights have confirmed the area appears
free of beluga whales. This measure would only apply to 2D and 3D
seismic surveying, not to other sound sources related to geohazard
survey or well construction.
Clearing the Exclusion Zone--Prior to the start of daily activities
for which take has been requested or if activities have been stopped
for longer than a 30-minute period, the PSOs will ensure the EZ is
clear of marine mammals for a period of 30 minutes. Clearing the EZ
means no marine mammals have been observed within the EZ for that 30-
minute period. If any marine mammals have been observed within the EZ,
ramp up cannot start until the marine mammal has left the EZ or has not
been observed for a 30-minute period prior to the start of the survey.
Power Downs--A power down procedure involves reducing the number of
airguns in use, which reduces the SZ radius and was proposed by Hilcorp
in their application. In contrast, a shut down procedure occurs when
all airgun activity is suspended immediately. During a power down, a
mitigation airgun is operated for no longer than three hours. Operation
of the mitigation gun allows the size of the SZ to decrease to the size
of the EZ for marine mammals other than beluga whales. If a marine
mammal is detected outside the original SZ but is likely to enter that
zone, the airguns may be powered down before the animal is within the
safety radius, as an alternative to a complete shutdown. Likewise, if a
marine mammal is already within the original SZ when first detected,
the airguns may be powered down if the PSOs determine it is a
reasonable alternative to an immediate shutdown. If a marine mammal is
already within the EZ when first detected, the airguns will be shut
down immediately.
Following a power down, airgun activity will not resume until the
marine mammal has cleared the original SZ. The animal will be
considered to have cleared the original SZ if it:
Is visually observed to have left the SZ,
Has not been seen within the SZ for 15 min in the case of
pinnipeds, and porpoises, or
Has not been seen within the SZ for 30 min in the case of
cetaceans.
Shutdowns--A shutdown is defined as suspending all airgun and sub-
bottom profiler activities. Shutdowns are not implemented for the other
activities in
[[Page 12367]]
Hilcorp's petition that are unlikely to result in take as they are not
easily turned off instantaneously. The operating airguns or profiler
will be shut down completely if a marine mammal is within or enters the
EZ. The operations will shut down completely if a beluga whale is
sighted within or entering the SZ or EZ. The shutdown procedure must be
accomplished within several seconds (of a ``one shot'' period) of the
determination that a marine mammal is within or enters the EZ.
Following a shutdown, airgun or sub-bottom profiler activity may be
reactivated only after the protected species has been observed exiting
the applicable 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 15 min in the case of
pinnipeds and porpoises
Has not been seen within the EZ for 30 min in the case of
cetaceans (except for beluga whales which cannot not be seen in the EZ
or SZ).
Ramp up--A ``ramp up'' procedure gradually increases airgun volume
at a specified rate. Ramp up is used at the start of airgun operations,
including after a power down, shutdown, and after 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. During the ramp up, the EZ for the full airgun
array will be maintained.
If the complete EZ has not been visible for at least 30 minutes
prior to the start of operations, ramp up will not commence unless the
mitigation gun has been operating since the power down of seismic
survey operations. This means that it will not be permissible to ramp
up the 24-gun source from a complete shut down 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 marine mammal is sighted within or
entering the EZ at any time.
Speed or Course Alteration--If a marine mammal is detected outside
the EZ and, based on its position and relative motion, is likely to
enter the EZ, the vessel's speed and/or direct course may, when
practical and safe, be changed. This technique also minimizes the
effect on the seismic program. This technique can be used in
coordination with a power down procedure. The marine mammal activities
and movements relative to the seismic and support vessels will be
closely monitored to ensure that the marine mammal does not enter the
EZ. If the mammal appears likely to enter the EZ, further mitigation
actions must be taken, i.e., either further course alterations, power
down, or shutdown of the airguns.
Pipe and Sheet Pile Driving Mitigation
Soon after the drill rig is positioned on the well head, the
conductor pipe will be driven as the first stage of the drilling
operation. Two PSOs (one operating at a time) will be stationed aboard
the rig during this two to three day operation monitoring the EZ and
the SZ. The impact hammer operator will be notified to shut down
hammering operations if a marine mammal is sighted within or enters the
EZ. A soft start of the hammering will begin at the start of each
hammering session. The soft start procedure involves initially starting
with three soft strikes, 30 seconds apart. This delayed-strike start
alerts marine mammals of the pending hammering activity and provides
them time to vacate the area. Monitoring will occur during all
hammering sessions.
A dock face will be constructed on the rock causeway in Iniskin
Bay. Two PSOs will be stationed either on a vessel or on land during
the 14-21 day operation observing an EZ of 4.6 km for beluga whales.
PSOs will implement similar monitoring and mitigation strategies as for
the pipe installation.
For impact hammering, ``soft-start'' technique must be used at the
beginning of each day's pipe/pile driving activities to allow any
marine mammal that may be in the immediate area to leave before pile
driving reaches full energy.
Clear the EZ 30 minutes prior to a soft-start to ensure no
marine mammals are within or entering the EZ.
Begin impact hammering soft-start with an initial set of
three strikes from the impact hammer at 40 percent energy, followed by
a one minute waiting period, then two subsequent 3-strike sets.
Immediately shut down all hammers at any time a marine
mammal is detected entering or within the EZ.
Initial hammering starts will not begin during periods of
poor visibility (e.g., night, fog, wind).
Any shutdown due to a marine mammal 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.
Water Jet Mitigation
A PSO will be present on the dive support vessel when divers are
using the water jet. Prior to in-water use of the water jet, the EZ
around the DSV will be established. The water jet will be shut down if
marine mammals are observed within the EZ.
Beluga Critical Habitat Mitigation
Hilcorp must not operate noise producing activities within 10 miles
(16 km) of the mean higher high water (MHHW) line of the Susitna Delta
(Beluga River to the Little Susitna River) between April 15 and October
15. The purpose of this mitigation measure is to protect beluga whales
in the designated critical habitat in this area that is important for
beluga whale feeding and calving during the spring and fall months. The
range of the setback required by NMFS was designated to protect this
important habitat area and also to create an effective buffer where
sound does not encroach on this habitat. This seasonal exclusion is
proposed to be in effect from April 15-October 15. Activities can occur
within this area from October 16-April 14.
Mitigation for Subsistence Uses of Marine Mammals or Plan of
Cooperation
Regulations at 50 CFR 216.104(a)(12) further require Incidental
Take Authorization applicants conducting activities that take place in
Arctic waters to provide a Plan of Cooperation or information that
identifies what measures have been taken and/or will be taken to
minimize adverse effects on the availability of marine mammals for
subsistence purposes. A plan must include the following:
A statement that the applicant has notified and provided
the affected subsistence community with a draft plan of cooperation;
A schedule for meeting with the affected subsistence
communities to discuss proposed activities and to resolve potential
conflicts regarding any aspects of either the operation or the plan of
cooperation;
A description of what measures the applicant has taken
and/or will take to ensure that proposed activities will not interfere
with subsistence whaling or sealing; and
What plans the applicant has to continue to meet with the
affected communities, both prior to and while conducting the activity,
to resolve conflicts and to notify the communities of any changes in
the operation.
Hilcorp Alaska has developed a Stakeholder Engagement Plan (SEP)
and
[[Page 12368]]
will implement this plan throughout the duration of the Petition. The
SEP will help coordinate activities with local stakeholders and thus
subsistence users, minimize the risk of interfering with subsistence
hunting activities, and keep current as to the timing and status of the
subsistence hunts. The Plan is provided in Appendix B of Hilcorp's
application.
Presentations will be given at various local forums. Hilcorp Alaska
is working with a contractor to update/verify our existing stakeholder
list. Meetings and communication will be coordinated with: commercial
and sport fishing groups/associations, various Native fisheries and
entities as it pertains to subsistence fishing and/or hunting, marine
mammal co-management groups, Cook Inlet Regional Citizens Advisory
Council, local landowners, government and community organizations, and
environmental NGOs.
Based on our evaluation of the applicant's proposed measures, as
well as other measures considered by NMFS, NMFS has preliminarily
determined that the proposed mitigation measures provide the means
effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance, and on the
availability of such species or stock for subsistence uses.
Proposed Monitoring and Reporting
In order to issue an LOA for an activity, section 101(a)(5)(A) of
the MMPA states that NMFS must set forth, requirements pertaining to
the monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
The PSOs will observe and collect data on marine mammals in and
around the project area for 15 (well activity) or 30 minutes (seismic
activity) before, during, and for 30 minutes after all of Hilcorp's
activities for which take has been requested.
Protected Species Observer Qualifications
NMFS-approved PSOs must meet the following requirements:
1. Independent observers (i.e., not construction personnel) are
required;
2. At least one observer must have prior experience working as an
observer;
3. Other observers may substitute education (undergraduate degree
in biological science or related field) or training for experience;
4. Where a team of three or more observers are required, one
observer should be designated as lead observer or monitoring
coordinator. The lead observer must have prior experience working as an
observer; and
5. NMFS will require submission and approval of observer CVs.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
Proposed Monitoring Measures
Sound Source Verification--When site-specific measurements are not
available for noise sources of concern for acoustic exposure, NMFS
often requires a sound source verification (SSV) to characterize the
sound levels, propagation, and to verify the monitoring zones (EZ and
SZ). Hilcorp Alaska plans to perform an SSV for the 3D seismic survey
and sub-bottom profiler in lower Cook Inlet. Hilcorp Alaska will work
with NMFS to determine if an SSV is needed for other activities
occurring in the action area.
Hilcorp will implement a robust monitoring and mitigation program
for marine mammals using NMFS-approved PSOs for Petition activities.
Much of the activities will use vessel-based PSOs, but land- or
platform-based PSOs may also be used to augment project-specific
activities. Marine mammal monitoring and mitigation methods have been
designed to meet the requirements and objectives which will be
specified in the Incidental Take Regulations promulgated by NMFS. Some
details of the monitoring and mitigation program may change upon
receipt of the individual LOAs issued by NMFS each year.
The main purposes of PSOs are: To conduct visual watches for marine
mammals; to serve as the basis for implementation of mitigation
measures; to document numbers of marine mammals present; to record any
reactions of marine mammals to Hilcorp's activities; and, to identify
whether there was any possible effect on accessibility of marine
mammals to subsistence hunters in Cook Inlet. These observations will
provide the real-time data needed to implement some of the key
measures.
PSOs will be on watch during all daylight periods for project-
specific activities. Generally, work is conducted 24-hrs a day,
depending on the specific activity.
For 2D seismic surveys, the airgun operations will be
conducted during daylight hours.
For 3D seismic surveys, airgun operations will continue
during the waning nighttime hours (ranges from 2230-0600 in early April
to 0100-0300 in mid-May) as long as the full array or mitigation gun is
operating prior to nightfall and mitigation airgun use cannot be longer
than three hours. Night vision and infrared have been suggested for low
visibility conditions, but these have not been useful in Cook Inlet or
other Alaska-based programs. Passive acoustic monitoring has also been
used in Cook Inlet and is typically required for seismic surveys but
has not shown to be an effective solution in Cook Inlet's specific
environmental conditions. A further discussion of previous passive
acoustic monitoring efforts by several entities in Cook Inlet is
provided in Section 13 of Hilcorp's application.
For the sub-bottom profiler, operations will generally be
conducted during daylight hours but may continue into the low
visibility period as long as the profiler is operating prior to
[[Page 12369]]
nightfall. Sub-bottom profiler operations may not begin under low
visibility conditions.
For pipe driving, VSP, and sheet pile driving, operations
will generally be conducted during daylight hours.
Water jet and hydraulic grinder are operated over a 24-
hour period as they are limited to low tide conditions. Activities will
not start during nighttime but will continue if already started.
Pre-Activity Monitoring--The exclusion zone will be monitored for
30 minutes prior to in-water construction/demolition activities. If a
marine mammal is present within the exclusion zone, the activity will
be delayed until the animal(s) leave the exclusion zone. Activity will
resume only after the PSO has determined that, through sighting or by
waiting (15 minutes for pinnipeds and porpoises, 30 minutes for
cetaceans) without re-sighting, the animal(s) has moved outside the
exclusion zone. If a marine mammal is observed within or entering the
exclusion zone, the PSO who sighted that animal will notify all other
PSOs and Hilcorp of its presence.
Post-Activity Monitoring--Monitoring of all zones will continue for
30 minutes following the completion of the activity.
For all activities, the PSOs will watch for marine mammals from the
best available vantage point on the vessel or station. Ideally this
vantage point is an elevated stable platform from which the PSO has an
unobstructed 360[deg] view of the water. The PSOs will scan
systematically with the naked eye and with binoculars. When a mammal
sighting is made, the following information about the sighting will be
carefully and accurately recorded:
Species, group size, age/size/sex categories (if
determinable), behavior when first sighted and after initial sighting,
heading (if consistent), bearing and distance from the PSO, apparent
reaction to activities (e.g., none, avoidance, approach, paralleling),
closest point of approach, and behavioral pace.
Time, location, speed, activity of the vessel, sea state,
ice cover, visibility, and sun glare.
The positions of other vessel(s) in the vicinity of the
PSO location.
The vessel's position, speed, water depth, sea state, ice
cover, visibility, and sun glare will also be recorded at the start and
end of each observation watch, every 30 minutes during a watch, and
whenever there is a change in any of those variables.
An electronic database or paper form will be used to record and
collate data obtained from visual observations.
The results of the PSO monitoring, including estimates of exposure
to key sound levels, will be presented in weekly, monthly, and 90-day
reports. Reporting will address the requirements established by NMFS in
the LOAs. The technical report(s) will include the list below.
Summaries of monitoring effort: Total hours, total
distances, and distribution of marine mammals throughout the study
period compared to sea state, and other factors affecting visibility
and detectability of marine mammals;
Analyses of the effects of various factors influencing
detectability of marine mammals: sea state, number of observers, and
fog/glare;
Species composition, occurrence, and distribution of
marine mammal sightings including date, water depth, numbers, age/size/
gender categories (when discernable), group sizes, and ice cover; and
Analyses of the effects of seismic program:
[cir] Sighting rates of marine mammals during periods with and
without project activities (and other variables that could affect
detectability);
[cir] Initial sighting distances versus project activity;
[cir] Closest point of approach versus project activity;
[cir] Observed behaviors and types of movements versus project
activity;
[cir] Numbers of sightings/individuals seen versus project
activity;
[cir] Distribution around the vessels versus project activity;
[cir] Summary of implemented mitigation measures; and
[cir] Estimates of ``take by harassment.''
Proposed Reporting Measures
Immediate reports will be submitted to NMFS if 30 or more belugas
are detected over the course of annual operations in the safety and
exclusion zones during operation of sound sources to evaluate and make
necessary adjustments to monitoring and mitigation. If the number of
detected takes for any marine mammal species is met or exceeded,
Hilcorp will immediately cease survey operations involving the use of
active sound sources (e.g., airguns and pingers) and notify NMFS Office
of Protected Resources (OPR).
1. Weekly Reports (during years with seismic surveying only)--
Hilcorp would submit a weekly field report to NMFS Headquarters as well
as the Alaska Regional Office, no later than close of business each
Thursday during the weeks when in-water seismic survey activities take
place. The weekly field reports would summarize species detected
(number, location, distance from seismic vessel, behavior), in-water
activity occurring at the time of the sighting (discharge volume of
array at time of sighting, seismic activity at time of sighting, visual
plots of sightings, and number of power downs and shutdowns),
behavioral reactions to in-water activities, and the number of marine
mammals exposed.
2. Monthly Reports- Monthly reports will be submitted to NMFS for
all months during which in-water seismic activities take place. The
monthly report will contain and summarize the following information:
Dates, times, locations, heading, speed, weather, sea
conditions (including Beaufort sea state and wind force), and
associated activities during all seismic operations and marine mammal
sightings.
Species, number, location, distance from the vessel, and
behavior of any sighted marine mammals, as well as associated seismic
activity (number of power-downs and shutdowns), observed throughout all
monitoring activities.
An estimate of the number (by species) exposed to the
seismic activity (based on visual observation) at received levels
greater than or equal to the NMFS thresholds discussed above with a
discussion of any specific behaviors those individuals exhibited.
A description of the implementation and effectiveness of
the: (i) Terms and conditions of the Biological Opinion's Incidental
Take Statement (ITS); and (ii) mitigation measures of the LOA. For the
Biological Opinion, the report must confirm the implementation of each
Term and Condition, as well as any conservation recommendations, and
describe their effectiveness for minimizing the adverse effects of the
action on ESA-listed marine mammals.
3. Annual Reports--Hilcorp must submit an annual report within 90
days after each activity year, starting from the date when the LOA is
issued (for the first annual report) or from the date when the previous
annual report ended. The annual report would include:
Summaries of monitoring effort (e.g., total hours, total
distances, and marine mammal distribution through the study period,
accounting for sea state and other factors affecting visibility and
detectability of marine mammals).
Analyses of the effects of various factors influencing
detectability of marine mammals (e.g., sea state, number of observers,
and fog/glare).
Species composition, occurrence, and distribution of
marine mammal sightings, including date, water depth, numbers, age/
size/gender categories (if
[[Page 12370]]
determinable), group sizes, and ice cover.
Analyses of the effects of survey operations.
Sighting rates of marine mammals during periods with and
without seismic survey activities (and other variables that could
affect detectability), such as: (i) Initial sighting distances versus
survey activity state; (ii) closest point of approach versus survey
activity state; (iii) observed behaviors and types of movements versus
survey activity state; (iv) numbers of sightings/individuals seen
versus survey activity state; (v) distribution around the source
vessels versus survey activity state; and (vi) numbers of animals
detected in the harassment/safety zone.
NMFS would review the draft annual reports. Hilcorp must then
submit a final annual report to the Chief, Permits and Conservation
Division, Office of Protected Resources, NMFS, within 30 days after
receiving comments from NMFS on the draft annual report. If NMFS
decides that the draft annual report needs no comments, the draft
report will be considered to be the final report.
3. Discovery of Injured or Dead Marine Mammals--In the event that
personnel involved in the survey activities covered by the
authorization discover an injured or dead marine mammal, Hilcorp must
report the incident to the Office of Protected Resources (OPR), NMFS
and to the Alaska Regional stranding coordinator as soon as feasible.
The report must include the following information:
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive;
If available, photographs or video footage of the
animal(s); and
General circumstances under which the animal was
discovered.
Vessel Strike--In the event of a ship strike of a marine mammal by
any vessel involved in the activities covered by the authorization,
Hilcorp must report the incident to OPR, NMFS and to regional stranding
coordinator as soon as feasible. The report must include the following
information:
Time, date, and location (latitude/longitude) of the
incident;
Species identification (if known) or description of the
animal(s) involved;
Vessel's speed during and leading up to the incident;
Vessel's course/heading and what operations were being
conducted (if applicable);
Status of all sound sources in use;
Description of avoidance measures/requirements that were
in place at the time of the strike and what additional measures were
taken, if any, to avoid strike;
Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, visibility) immediately preceding the
strike;
Estimated size and length of animal that was struck;
Description of the behavior of the marine mammal
immediately preceding and following the strike;
If available, description of the presence and behavior of
any other marine mammals immediately preceding the strike;
Estimated fate of the animal (e.g., dead, injured but
alive, injured and moving, blood or tissue observed in the water,
status unknown, disappeared); and
To the extent practicable, photographs or video footage of
the animal(s).
Actions to Minimize Additional Harm to Live-Stranded (or Milling)
Marine Mammals--In the event of a live stranding (or near-shore
atypical milling) event within 50 km of the survey operations, where
the NMFS stranding network is engaged in herding or other interventions
to return animals to the water, the Director of OPR, NMFS (or designee)
will advise the Hilcorp of the need to implement shutdown procedures
for all active acoustic sources operating within 50 km of the
stranding. Shutdown procedures for live stranding or milling marine
mammals include the following:
If at any time, the marine mammals die or are euthanized,
or if herding/intervention efforts are stopped, the Director of OPR,
NMFS (or designee) will advise Hilcorp that the shutdown around the
animals' location is no longer needed.
Otherwise, shutdown procedures will remain in effect until
the Director of OPR, NMFS (or designee) determines and advises Hilcorp
that all live animals involved have left the area (either of their own
volition or following an intervention).
If further observations of the marine mammals indicate the
potential for re- stranding, additional coordination with Hilcorp will
be required to determine what measures are necessary to minimize that
likelihood (e.g., extending the shutdown or moving operations farther
away) and to implement those measures as appropriate.
Shutdown procedures are not related to the investigation of the
cause of the stranding and their implementation is not intended to
imply that the specified activity is the cause of the stranding.
Rather, shutdown procedures are intended to protect marine mammals
exhibiting indicators of distress by minimizing their exposure to
possible additional stressors, regardless of the factors that
contributed to the stranding.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat, and the likely effectiveness
of the mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing sources of human-caused mortality, or
ambient noise levels).
Given the nature of activities, proposed mitigation and related
monitoring, no serious injuries or mortalities are anticipated to occur
as a result of Hilcorp's proposed oil and gas activities in Cook Inlet,
and none are proposed to be authorized. The number of takes that are
anticipated and proposed to be authorized are expected to be limited
mostly to short-term Level B harassment, although some PTS may occur.
The seismic airguns and other
[[Page 12371]]
sound sources do not operate continuously over a 24-hour period. Rather
the airguns are operational for a few hours at a time with breaks in
between, as surveys can only be conducted during slack tides, totaling
a maximum of 12 hours a day for the most frequently used equipment.
Sources other than airguns are likely to be used for much shorter
durations daily than the 12 potential hours of airgun use.
Cook Inlet beluga whales, the Mexico DPS of humpback whales, fin
whales, and the western stock of Steller sea lions are listed as
endangered under the ESA. These stocks are also considered depleted
under the MMPA. Beluga-specific mitigation measures, such as shutting
down whenever beluga whales are sighted by PSOs and an exclusion zone
at the Susitna River Delta months of high beluga concentrations, aim to
minimize the effects of this activity on the population. Zerbini et al.
(2006) estimated rates of increase of fin whales in coastal waters
south of the Alaska, and data from Calambokidis et al. (2008) suggest
the population of humpback whales by also be increasing. Steller sea
lion trends for the western stock are variable throughout the region
with some decreasing and others remaining stable or even indicating
slight increases. The other species that may be taken by harassment
during Hilcorp's proposed oil and gas program are not listed as
threatened or endangered under the ESA nor as depleted under the MMPA.
Odontocete (including Cook Inlet beluga whales, killer whales, and
harbor porpoises) reactions to seismic energy pulses are usually
assumed to be limited to shorter distances from the airgun(s) than are
those of mysticetes, in part because odontocete low-frequency hearing
is assumed to be less sensitive than that of mysticetes. When in the
Canadian Beaufort Sea in summer, belugas appear to be fairly responsive
to seismic energy, with few being sighted within 10-20 km (6-12 mi) of
seismic vessels during aerial surveys (Miller et al., 2005). However,
as noted above, Cook Inlet belugas are more accustomed to anthropogenic
sound than beluga whales in the Beaufort Sea. Therefore, the results
from the Beaufort Sea surveys may be less applicable to potential
reactions of Cook Inlet beluga whales. Also, due to the dispersed
distribution of beluga whales in Cook Inlet during winter and the
concentration of beluga whales in upper Cook Inlet from late April
through early fall (i.e., far north of the proposed seismic surveys),
belugas would likely occur in small numbers in the majority of
Hilcorp's proposed survey area during the majority of Hilcorp's annual
operational timeframe.
Taking into account the mitigation measures that are planned,
effects on cetaceans are generally expected to be restricted to
avoidance of a limited area around the survey operation and short-term
changes in behavior, falling within the MMPA definition of ``Level B
harassment.'' It is possible that Level A take of marine mammals from
sound sources such as seismic airguns may also occur. Due to the short
term duration of activities in any given area and the small geographic
area in which Hilcorp's activities would be occurring at any one time,
it is unlikely that these activities would affect reproduction or
survival of cetaceans in Cook Inlet. Animals are not expected to
permanently abandon any area that is surveyed, and any behaviors that
are interrupted during the activity are expected to resume once the
activity ceases. Only a small portion of marine mammal habitat will be
affected at any time, and other areas within Cook Inlet will be
available for necessary biological functions including breeding,
foraging, and mating. In addition, NMFS proposes to seasonally restrict
seismic survey operations in locations known to be important for beluga
whale feeding, calving, or nursing. One of the primary locations for
these biological life functions occur in the Susitna Delta region of
upper Cook Inlet. NMFS proposes to implement a 16 km (10 mi) seasonal
exclusion from activities for which take has been requested in this
region from April 15 to October 15 annually. The highest concentrations
of belugas are typically found in this area from early May through
September each year. NMFS has incorporated a 2-week buffer on each end
of this seasonal use timeframe to account for any anomalies in
distribution and marine mammal usage.
Mitigation measures, such as dedicated marine mammal observers, and
shutdowns or power downs when marine mammals are seen within defined
ranges, are designed both to further reduce short-term reactions and
minimize any effects on hearing sensitivity. In all cases, the effects
of these activities are expected to be short-term, with no lasting
biological consequence. Therefore, the exposure of cetaceans to sounds
produced by Hilcorp's proposed oil and gas activities is not
anticipated to have an effect on annual rates of recruitment or
survival of the affected species or stocks.
Some individual pinnipeds may be exposed to sound from the proposed
activities more than once during the timeframe of the project. Taking
into account the mitigation measures that are planned, effects on
pinnipeds are generally expected to be restricted to avoidance of a
limited area around the survey operation and short-term changes in
behavior, falling within the MMPA definition of ``Level B harassment,''
although some pinnipeds may approach close enough to sound sources
undetected and incur PTS. Due to the solitary nature of pinnipeds in
water, this is expected to be a small number of individuals and the
calculated distances to the PTS thresholds incorporate a relatively
long duration, making them conservative. Animals are not expected to
permanently abandon any area that is surveyed, and any behaviors that
are interrupted during the activity are expected to resume once the
activity ceases. Only a small portion of pinniped habitat will be
affected at any time, and other areas within Cook Inlet will be
available for necessary biological functions. In addition, the areas
where the activities will take place are largely offshore and not known
to be biologically important areas for pinniped populations. Therefore,
the exposure of pinnipeds to sounds produced by this phase of
Hilcorps's proposed activity is not anticipated to have an effect on
annual rates of recruitment or survival on those species or stocks.
The addition of multiple source and supply vessels, and noise due
to vessel operations associated with the activities, would not be
outside the present experience of marine mammals in Cook Inlet,
although levels may increase locally. Given the large number of vessels
in Cook Inlet and the apparent habituation to vessels by Cook Inlet
beluga whales and the other marine mammals that may occur in the area,
vessel activity and its associated noise is not expected to have
effects that could cause significant or long-term consequences for
individual marine mammals or their populations.
Potential impacts to marine mammal habitat were discussed
previously in this document (see the ``Anticipated Effects on Habitat''
section). Although some disturbance is possible to food sources of
marine mammals, the impacts are anticipated to be minor enough as to
not affect annual rates of recruitment or survival of marine mammals in
the area. Based on the size of Cook Inlet where feeding by marine
mammals occurs versus the localized area of the marine survey
activities, any missed feeding opportunities in the direct project area
would be minor based on the fact that other feeding areas exist
elsewhere. Additionally,
[[Page 12372]]
operations will not occur in the primary beluga feeding and calving
habitat during times of high use by those animals. The proposed
mitigation measure of limiting activities around the Susistna Delta
would also protect beluga whale prey and their foraging habitat.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
No mortality is anticipated or authorized;
Increased mitigation for beluga whales, including
shutdowns at any distance and exclusion zones and avoiding exposure
during critical foraging periods around the Susitna Delta;
Location of activities offshore which minimizes effects of
activity on resident pinnipeds at haulouts,
Concentration of seismic surveying in the lower portions
of Cook Inlet going into open water where densities of marine mammals
are less than other parts of the Inlet; and
Comprehensive land, sea, and aerial-based monitoring
maximizing marine mammal detection rates as well as acoustic SSV to
verify exposure levels.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under section 101(a)(5)(A) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so, in practice, NMFS compares the number of
individuals taken within a year to the most appropriate estimation of
abundance of the relevant species or stock in our determination of
whether an authorization is limited to small numbers of marine mammals.
Additionally, other qualitative factors may be considered in the
analysis, such as the temporal or spatial scale of the activities.
As described above in Table 18, the takes proposed to be authorized
represent less than 25 percent of any stock of population in the year
of maximum activity. Further, takes are expected to be significantly
lower in the years without 3D seismic activities. For species listed as
endangered under the ESA, takes proposed to be authorized represent no
more than nine percent of the stock of humpback whales, ten percent of
the stock of Cook Inlet beluga whales, and less than one percent of the
Northeastern Pacific stock of fin whales and Western DPS of Steller sea
lions.
NMFS finds that any incidental take reasonably likely to result
annually from the effects of the proposed activities, as proposed to be
mitigated through this rulemaking and LOA process, will be limited to
small numbers of the affected species or stock. In addition to the
quantitative methods used to estimate take, NMFS also considered
qualitative factors that further support the ``small numbers''
determination, including: (1) The seasonal distribution and habitat use
patterns of Cook Inlet beluga whales, which suggest that for much of
the time only a small portion of the population would be accessible to
impacts from Hilcorp's activity, as most animals are found in the
Susitna Delta region of Upper Cook Inlet from early May through
September; (2) other cetacean species and Steller sea lions are not
common in the action area; (3) the proposed mitigation requirements,
which provide spatio-temporal limitations that avoid impacts to large
numbers of belugas feeding and calving in the Susitna Delta and limit
exposures to sound levels associated with Level B harassment; (4) the
proposed monitoring requirements and mitigation measures described
earlier in this document for all marine mammal species that will
further reduce impacts and the amount of takes; and (5) monitoring
results from previous activities that indicated low numbers of beluga
whale sightings within the Level B disturbance exclusion zone and low
levels of Level B harassment takes of other marine mammals.
Additionally, the rationale provided in the Estimated Take section
above, estimates that the number of individual harbor seals like to be
exposed to noise that may cause harassment is significantly less than
the number of calculated exposure due to the resident nature of harbor
seals, offshore locations of the sound sources, and likelihood of
harbor seals to be hauled out on land at the time sound sources are
deployed.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals will be taken relative to the population size
of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an ITA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
That is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) placing physical barriers
between the marine mammals and the subsistence hunters; and (2) that
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
The project is unlikely to affect beluga whale harvests because no
beluga harvest will take place in 2019, nor is one likely to occur in
the other years that would be covered by the 5-year regulations and
associated LOAs. Additionally, the proposed action area is not an
important native subsistence site for other subsistence species of
marine mammals. Also, because of the relatively small number of marine
mammals harvested in Cook Inlet, the number affected by the proposed
action is expected to be extremely low. Therefore, because the proposed
action would result in only temporary disturbances, the proposed action
would not impact the availability of these other marine mammal species
for subsistence uses.
The timing and location of subsistence harvest of Cook Inlet harbor
seals may coincide with Hilcorp's project but, because this subsistence
hunt is conducted opportunistically and at such a low level (NMFS,
2013c), Hilcorp's program is not expected to have an impact on the
subsistence use of harbor seals.
NMFS anticipates that any effects from Hilcorp's proposed
activities on marine mammals, especially harbor seals and Cook Inlet
beluga whales, which are or have been taken for subsistence uses, would
be short-term, site specific, and limited to inconsequential changes in
behavior and mild stress responses. NMFS does not anticipate that the
authorized taking of affected species or stocks will reduce the
availability of the species to a level insufficient for a harvest to
meet subsistence needs by: (1) Causing the
[[Page 12373]]
marine mammals to abandon or avoid hunting areas; (2) directly
displacing subsistence users; or (3) placing physical barriers between
the marine mammals and the subsistence hunters. And any such potential
reductions could be sufficiently mitigated by other measures to
increase the availability of marine mammals to allow subsistence needs
to be met. Based on the description of the specified activity, the
measures described to minimize adverse effects on the availability of
marine mammals for subsistence purposes, and the proposed mitigation
and monitoring measures, NMFS has preliminarily determined that there
will not be an unmitigable adverse impact on subsistence uses from
Hilcorp's proposed activities.
Adaptive Management
The regulations governing the take of marine mammals incidental to
Hilcorp's proposed oil and gas activities would contain an adaptive
management component.
The reporting requirements associated with this proposed rule are
designed to provide NMFS with monitoring data from the previous year to
allow consideration of whether any changes are appropriate. The use of
adaptive management allows NMFS to consider new information from
different sources to determine (with input from Hilcorp regarding
practicability) on an annual basis if mitigation or monitoring measures
should be modified (including additions or deletions). Mitigation or
monitoring measures could be modified if new data suggests that such
modifications would have a reasonable likelihood more effectively
achieving the goals of the mitigation and monitoring and if the
measures are practicable.
The following are some of the possible sources of applicable data
to be considered through the adaptive management process: (1) Results
from monitoring reports, as required by MMPA authorizations; (2)
Results from general marine mammal and sound research; and (3) any
information which reveals that marine mammals may have been taken in a
manner, extent, or number not authorized by these regulations or
subsequent LOAs.
Endangered Species Act (ESA)
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of ITAs,
NMFS consults internally, in this case with the Alaska Protected
Resources Division Office, whenever we propose to authorize take for
endangered or threatened species.
NMFS is proposing to authorize take of Cook Inlet beluga whale,
Northeastern Pacific stock of fin whales, Western North Pacific,
Hawaii, and Mexico DPS of humpback whales, and western DPS of Steller
sea lions, which are listed under the ESA.
The Permit and Conservation Division has requested initiation of
section 7 consultation with the Alaska Region for the promulgation of
5-year regulations and the subsequent issuance of annual LOAs. NMFS
will conclude the ESA consultation prior to reaching a determination
regarding the proposed issuance of the authorization.
Classification
Pursuant to the procedures established to implement Executive Order
12866, the Office of Management and Budget has determined that this
proposed rule is not significant.
Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA),
the Chief Counsel for Regulation of the Department of Commerce has
certified to the Chief Counsel for Advocacy of the Small Business
Administration that this proposed rule, if adopted, would not have a
significant economic impact on a substantial number of small entities.
Hilcorp Alaska LLC is the only entity that would be subject to the
requirements in these proposed regulations. Hilcorp employs thousands
of people worldwide, and has a market value in the billions of dollars.
Therefore, Hilcorp is not a small governmental jurisdiction, small
organization, or small business, as defined by the RFA. Because of this
certification, a regulatory flexibility analysis is not required and
none has been prepared.
Notwithstanding any other provision of law, no person is required
to respond to nor shall a person be subject to a penalty for failure to
comply with a collection of information subject to the requirements of
the Paperwork Reduction Act (PRA) unless that collection of information
displays a currently valid OMB control number. This proposed rule
contains collection-of-information requirements subject to the
provisions of the PRA. These requirements have been approved by OMB
under control number 0648-0151 and include applications for
regulations, subsequent LOAs, and reports.
List of Subjects in 50 CFR Part 217
Penalties, Reporting and recordkeeping requirements, Seafood,
Transportation.
Dated: March 21, 2019.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
For reasons set forth in the preamble, 50 CFR part 217 is proposed
to be amended as follows:
PART 217--REGULATIONS GOVERNING THE TAKE OF MARINE MAMMALS
INCIDENTAL TO SPECIFIED ACTIVITIES
0
1. The authority citation for part 217 continues to read as follows:
Authority: 16 U.S.C. 1361 et seq.
0
2. Add subpart Q to part 217 to read as follows:
Subpart Q--Taking and Importing Marine Mammals; Taking Marine Mammals
Incidental to Oil and Gas Activities in Cook Inlet, Alaska
Sec.
217.160 Specified activity and specified geographical region.
217.161 Effective dates.
217.162 Permissible methods of taking.
217.163 Prohibitions.
217.164 Mitigation requirements.
217.165 Requirements for monitoring and reporting.
217.166 Letters of Authorization.
217.167 Renewals and modifications of Letters of Authorization
217.168--217.169 [Reserved]
Subpart Q--Taking and Importing Marine Mammals; Taking Marine
Mammals Incidental to Oil and Gas Activities in Cook Inlet, Alaska
Sec. 217.160 Specified activity and specified geographical region.
(a) Regulations in this subpart apply only to Hilcorp Alaska LLC
(Hilcorp) and those persons it authorizes or funds to conduct
activities on its behalf for the taking of marine mammals that occurs
in the area outlined in paragraph (b) of this section and that occurs
incidental to the activities described in paragraph (c) of this
section.
(b) The taking of marine mammals by Hilcorp may be authorized in
Letters of Authorization (LOAs) only if it occurs within the action
area defined in Cook Inlet, Alaska.
(c) The taking of marine mammals by Hilcorp is only authorized if
it occurs incidental to Hilcorp's oil and gas activities including use
of seismic airguns, sub-bottom profiler, vertical seismic profiling,
pile driving, conductor pipe driving, and water jets.
[[Page 12374]]
Sec. 217.161 Effective dates and definitions.
Regulations in this subpart are effective [EFFECTIVE DATE OF FINAL
RULE] through [DATE 5 YEARS AFTER EFFECTIVE DATE OF FINAL RULE].
Sec. 217.162 Permissible methods of taking.
Under LOAs issued pursuant to Sec. 216.106 of this chapter and
Sec. 217.166, the Holder of the LOAs (hereinafter ``Hilcorp'') may
incidentally, but not intentionally, take marine mammals within the
area described in Sec. 217.160(b) by Level A harassment and Level B
harassment associated with oil and gas activities, provided the
activity is in compliance with all terms, conditions, and requirements
of the regulations in this subpart and the applicable LOAs.
Sec. 217.163 Prohibitions.
Notwithstanding takings contemplated in Sec. 217.162 and
authorized by LOAs issued under Sec. Sec. 216.106 of this chapter and
217.166, no person in connection with the activities described in Sec.
217.160 may:
(a) Violate, or fail to comply with, the terms, conditions, and
requirements of this subpart or a LOA issued under Sec. Sec. 216.106
of this chapter and 217.166;
(b) Take any marine mammal not specified in such LOAs;
(c) Take any marine mammal specified in such LOAs in any manner
other than as specified;
(d) Take a marine mammal specified in such LOAs if NMFS determines
such taking results in more than a negligible impact on the species or
stocks of such marine mammal; or
(e) Take a marine mammal specified in such LOAs if NMFS determines
such taking results in an unmitigable adverse impact on the
availability of such species or stock of marine mammal for taking for
subsistence uses.
Sec. 217.164 Mitigation requirements.
When conducting the activities identified in Sec. 217.160(c), the
mitigation measures contained in any LOAs issued under Sec. Sec.
216.106 of this chapter and 217.166 must be implemented. These
mitigation measures must include but are not limited to:
(a) If any marine mammal species for which take is not authorized
are sighted within or entering the relevant zones within which they
would be exposed to sound above the 120 dB re 1 [micro]Pa (rms)
threshold for continuous (e.g., vibratory pile-driving, drilling)
sources or the 160 dB re 1 [micro]Pa (rms) threshold for non-explosive
impulsive (e.g., seismic airguns) or intermittent (e.g., scientific
sonar) sources, Hilcorp must take appropriate action to avoid such
exposure (e.g., by altering speed or course or by power down or
shutdown of the sound source).
(b) If the allowable number of takes in an LOA listed for any
marine mammal species is met or exceeded, Hilcorp must immediately
cease survey operations involving the use of active sound source(s),
record the observation, and notify NMFS Office of Protected Resources.
(c) Hilcorp must notify NMFS Office of Protected Resources at least
48 hours prior to the start of oil and gas activities each year.
(d) Hilcorp must conduct briefings as necessary between vessel
crews, marine mammal monitoring team, and other relevant personnel
prior to the start of all survey activity, and when new personnel join
the work, in order to explain responsibilities, communication
procedures, marine mammal monitoring protocol, and operational
procedures.
(e) Establishment of monitoring and exclusion zones. (1) For all
relevant in-water construction and demolition activity, Hilcorp must
implement shutdown zones/exclusion zones (EZs) with radial distances as
identified in any LOA issued under Sec. Sec. 216.106 of this chapter
and 217.166. If a marine mammal is sighted within or entering the EZ,
such operations must cease.
(2) For all relevant in-water construction and demolition activity,
Hilcorp must designate safety zones for monitoring (SZ)with radial
distances as identified in any LOA issued under Sec. Sec. 216.106 of
this chapter and 217.166 and record and report occurrence of marine
mammals within these zones.
(3) For all in-water construction and demolition activity, Hilcorp
must implement a minimum EZ of a 10 m radius around the source.
(f) Shutdown measures. (1) Hilcorp must deploy protected species
observers (PSOs) and PSOs must be posted to monitor marine mammals
within the monitoring zones during use of active acoustic sources and
pile driving in water.
(2) Monitoring must begin 15 minutes prior to initiation of
stationary source activity and 30 minutes prior to initiation of mobile
source activity, occur throughout the time required to complete the
activity, and continue through 30 minutes post-completion of the
activity. Pre-activity monitoring must be conducted to ensure that the
EZ is clear of marine mammals, and activities may only commence once
observers have declared the EZ clear of marine mammals. In the event of
a delay or shutdown of activity resulting from marine mammals in the
EZ, the marine mammals' behavior must be monitored and documented.
(3) A determination that the EZ is clear must be made during a
period of good visibility (i.e., the entire EZ must be visible to the
naked eye).
(4) If a marine mammal is observed within or entering the EZ,
Hilcorp must halt all noise producing activities for which take is
authorized at that location. If activity is delayed due to the presence
of a marine mammal, the activity may not commence or resume until
either the animal has voluntarily left and been visually confirmed
outside the EZ or the required amount of time (15 for porpoises and
pinnipeds, 30 minutes for cetaceans) have passed without re-detection
of the animal.
(5) Monitoring must be conducted by trained observers, who must
have no other assigned tasks during monitoring periods. Trained
observers must be placed at the best vantage point(s) practicable to
monitor for marine mammals and implement shutdown or delay procedures
when applicable through communication with the equipment operator.
Hilcorp must adhere to the following additional observer
qualifications:
(i) Hilcorp must use independent, dedicated, trained visual PSOs,
meaning that the PSOs must be employed by a third-party observer
provider, must not have tasks other than to conduct observational
effort, collect data, and communicate with and instruct relevant vessel
crew with regard to the presence of protected species and mitigation
requirements (including brief alerts regarding maritime hazards), and
must have successfully completed an approved PSO training course
appropriate for their designated task.
(ii) Hilcorp must submit PSO resumes for NMFS review and approval.
Resumes must be accompanied by a relevant training course information
packet that includes the name and qualifications (i.e., experience,
training completed, or educational background) of the instructor(s),
the course outline or syllabus, and course reference material as well
as a document stating successful completion of the course. NMFS is
allowed one week to approve PSOs from the time that the necessary
information is received by NMFS, after which PSOs meeting the minimum
requirements will automatically be considered approved.
(iii) To the maximum extent practicable, the lead PSO must devise
the duty schedule such that experienced PSOs are on duty with those
PSOs with appropriate training but who have not yet gained relevant
experience.
(6) Hilcorp must implement shutdown measures if the number of
[[Page 12375]]
authorized takes for any particular species reaches the limit under the
applicable LOA and if such marine mammals are sighted within the
vicinity of the project area and are entering the SZ during activities.
(7) Hilcorp must implement a shutdown if a beluga whale is seen
within or entering the EZ or SZ.
(g) Impact driving soft start. (1) Hilcorp must implement soft
start techniques for impact pile driving. Hilcorp must conduct an
initial set of three strikes from the impact hammer 30 seconds apart,
at 40 percent energy, followed by a 1-minute waiting period, then two
subsequent three strike sets.
(2) Soft start is required for any impact driving, including at the
beginning of the day, after 30 minutes of pre-activity monitoring, and
at any time following a cessation of impact pile driving of 30 minutes
or longer.
(h) Airgun ramp up. (1) Ramp up must be used at the start of airgun
operations, including after a power down, shutdown, and after any
period greater than 10 minutes in duration without airgun operations.
(2) The rate of ramp up must be no more than 6 dB per 5-minute
period.
(3) Ramp up must begin with the smallest gun in the array that is
being used for all airgun array configurations.
(4) During the ramp up, the EZ for the full airgun array must be
implemented.
(5) If the complete EZ has not been visible for at least 30 minutes
prior to the start of operations, ramp up must not commence.
(6) Ramp up of the airguns must not be initiated if a marine mammal
is sighted within or entering the EZ at any time.
(i) Airgun power down. (1) If a marine mammal, other than a beluga
whale, is detected outside the safety zone (SZ) but is likely to enter
that zone, the airguns may be powered down before the animal is within
the safety zone, as an alternative to a complete shutdown. Likewise, if
a marine mammal is already within the SZ when first detected, the
airguns may be powered down if the PSOs determine it is a reasonable
alternative to an immediate shutdown. If a marine mammal is already
within the EZ when first detected, the airguns must be shut down
immediately.
(2) Following a power down, airgun activity must not resume until
the marine mammal has cleared the SZ. The animal will be considered to
have cleared the SZ if it:
(i) Is visually observed to have left the SZ; or
(ii) Has not been seen within the SZ for 15 min in the case of
pinnipeds and porpoises; or
(iii) Has not been seen within the SZ for 30 min in the case of
cetaceans.
(3) A mitigation airgun must not operate for longer than three
hours.
(j) Aircraft mitigation. (1) Hilcorp must use aircraft daily to
survey the planned seismic survey area prior to the start of seismic
surveying. Surveying must not begin unless the aerial flights confirm
the proposed survey area for that day is clear of beluga whales.
(2) If beluga whales are sighted during flights, start of seismic
surveying must be delayed until it is confirmed the area is free of
beluga whales.
(k) Beluga exclusion zone. Hilcorp must not operate with noise
producing activity within 10 miles (16 km) of the mean higher high
water (MHHW) line of the Susitna Delta (Beluga River to the Little
Susitna River) between April 15 and October 15.
Sec. 217.165 Requirements for monitoring and reporting.
(a) Marine Mammal Monitoring Protocols. Hilcorp must conduct
briefings between construction supervisors and crews and the observer
team prior to the start of all pile driving and removal activities, and
when new personnel join the work. Trained observers must receive a
general environmental awareness briefing conducted by Hilcorp staff. At
minimum, training must include identification of marine mammals that
may occur in the project vicinity and relevant mitigation and
monitoring requirements. All observers must have no other construction-
related tasks while conducting monitoring.
(b) Activities must only commence when the entire exclusion zone
(EZ) is visible to the naked eye and can be adequately monitored. If
conditions (e.g., fog) prevent the visual detection of marine mammals,
activities must not be initiated. For activities other than seismic
surveying, activity would be halted in low visibility but vibratory
pile driving or removal would be allowed to continue if started in good
visibility.
(c) Monitoring must begin 15 minutes prior to initiation of
stationary source activity and 30 minutes prior to initiation of mobile
source activity, occur throughout the time required to complete the
activity, and continue through 30 minutes post-completion of the
activity. Pre-activity monitoring must be conducted to ensure that the
EZ is clear of marine mammals, and activities may only commence once
observers have declared the EZ clear of marine mammals. In the event of
a delay or shutdown of activity resulting from marine mammals in the
EZ, the animals' behavior must be monitored and documented.
(d) Reporting Measures. (1) Weekly reports. Hilcorp must submit
weekly reports during the weeks when in-water seismic survey activities
take place. The weekly field reports would summarize species detected
(number, location, distance from seismic vessel, behavior), in-water
activity occurring at the time of the sighting (discharge volume of
array at time of sighting, seismic activity at time of sighting, visual
plots of sightings, and number of power downs and shutdowns),
behavioral reactions to in-water activities, and the number of marine
mammals exposed.
(2) Monthly reports. Monthly reports must be submitted to NMFS for
all months during which in-water seismic activities take place. The
monthly report must contain and summarize the following information:
Dates, times, locations, heading, speed, weather, sea conditions
(including Beaufort sea state and wind force), and associated
activities during all seismic operations and marine mammal sightings;
Species, number, location, distance from the vessel, and behavior of
any sighted marine mammals, as well as associated seismic activity
(number of power-downs and shutdowns), observed throughout all
monitoring activities; An estimate of the number (by species) exposed
to the seismic activity (based on visual observation) at received
levels greater than or equal to the NMFS thresholds discussed above
with a discussion of any specific behaviors those individuals
exhibited; A description of the implementation and effectiveness of the
terms and conditions of the Biological Opinion's Incidental Take
Statement (ITS) and mitigation measures of the LOA.
(3) Annual Reports. (i) Hilcorp must submit an annual report within
90 days after each activity year, starting from the date when the LOA
is issued (for the first annual report) or from the date when the
previous annual report ended.
(ii) Annual reports would detail the monitoring protocol, summarize
the data recorded during monitoring, and estimate the number of marine
mammals that may have been harassed during the period of the report.
(iii) NMFS would provide comments within 30 days after receiving
annual reports, and Hilcorp must address the comments and submit
revisions within 30 days after receiving NMFS comments. If no comment
is received from the NMFS within 30 days, the annual report will be
considered completed.
(4) Final report. (i) Hilcorp must submit a comprehensive summary
[[Page 12376]]
report to NMFS not later than 90 days following the conclusion of
marine mammal monitoring efforts described in this subpart.
(ii) The final report must synthesize all data recorded during
marine mammal monitoring, and estimate the number of marine mammals
that may have been harassed through the entire project.
(iii) NMFS would provide comments within 30 days after receiving
this report, and Hilcorp must address the comments and submit revisions
within 30 days after receiving NMFS comments. If no comment is received
from the NMFS within 30 days, the final report will be considered as
final.
(5) Reporting of injured or dead marine mammals. (i) In the event
that personnel involved in the survey activities discover an injured or
dead marine mammal, Hilcorp must report the incident to the Office of
Protected Resources (OPR), NMFS (301-427-8401) and to regional
stranding network (877-925-7773) as soon as feasible. The report must
include the following information:
(A) Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
(B) Species identification (if known) or description of the
animal(s) involved;
(C) Condition of the animal(s) (including carcass condition if the
animal is dead);
(D) Observed behaviors of the animal(s), if alive;
(E) If available, photographs or video footage of the animal(s);
and
(F) General circumstances under which the animal was discovered.
(ii) In the event of a ship strike of a marine mammal by any vessel
involved in the survey activities, Hilcorp must report the incident to
OPR, NMFS and to regional stranding networks as soon as feasible. The
report must include the following information:
(A) Time, date, and location (latitude/longitude) of the incident;
(B) Species identification (if known) or description of the
animal(s) involved;
(C) Vessel's speed during and leading up to the incident;
(D) Vessel's course/heading and what operations were being
conducted (if applicable);
(E) Status of all sound sources in use;
(F) Description of avoidance measures/requirements that were in
place at the time of the strike and what additional measures were
taken, if any, to avoid strike;
(G) Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, visibility) immediately preceding the
strike;
(H) Estimated size and length of animal that was struck;
(I) Description of the behavior of the marine mammal immediately
preceding and following the strike;
(J) If available, description of the presence and behavior of any
other marine mammals immediately preceding the strike;
(K) Estimated fate of the animal (e.g., dead, injured but alive,
injured and moving, blood or tissue observed in the water, status
unknown, disappeared); and
(L) To the extent practicable, photographs or video footage of the
animal(s).
(iii) In the event of a live stranding (or near-shore atypical
milling) event within 50 km of the survey operations, where the NMFS
stranding network is engaged in herding or other interventions to
return animals to the water, the Director of OPR, NMFS (or designee)
will advise Hilcorp of the need to implement shutdown procedures for
all active acoustic sources operating within 50 km of the stranding.
Shutdown procedures for live stranding or milling marine mammals
include the following:
(A) If at any time, the marine mammal(s) die or are euthanized, or
if herding/intervention efforts are stopped, the Director of OPR, NMFS
(or designee) will advise Hilcorp that the shutdown around the animals'
location is no longer needed.
(B) Otherwise, shutdown procedures must remain in effect until the
Director of OPR, NMFS (or designee) determines and advises Hilcorp that
all live animals involved have left the area (either of their own
volition or following an intervention).
(C) If further observations of the marine mammals indicate the
potential for re-stranding, additional coordination with Hilcorp must
occur to determine what measures are necessary to minimize that
likelihood (e.g., extending the shutdown or moving operations farther
away) and Hilcorp must implement those measures as appropriate.
(iv) If NMFS determines that the circumstances of any marine mammal
stranding found in the vicinity of the activity suggest investigation
of the association with survey activities is warranted, and an
investigation into the stranding is being pursued, NMFS will submit a
written request to Hilcorp indicating that the following initial
available information must be provided as soon as possible, but no
later than 7 business days after the request for information.
(A) Status of all sound source use in the 48 hours preceding the
estimated time of stranding and within 50 km of the discovery/
notification of the stranding by NMFS; and
(B) If available, description of the behavior of any marine
mammal(s) observed preceding (i.e., within 48 hours and 50 km) and
immediately after the discovery of the stranding.
(C) In the event that the investigation is still inconclusive, the
investigation of the association of the survey activities is still
warranted, and the investigation is still being pursued, NMFS may
provide additional information requests, in writing, regarding the
nature and location of survey operations prior to the time period
above.
Sec. 217.166 Letters of authorization.
(a) To incidentally take marine mammals pursuant to these
regulations, Hilcorp must apply for and obtain (LOAs) in accordance
with Sec. 216.106 of this chapter for conducting the activity
identified in Sec. 217.160(c).
(b) LOAs, unless suspended or revoked, may be effective for a
period of time not to extend beyond the expiration date of these
regulations.
(c) An LOA application must be submitted to the Director, Office of
Protected Resources, NMFS, by December 31st of the year preceding the
desired start date.
(d) An LOA application must include the following information:
(1) The date(s), duration, and the area(s) where the activity will
occur;
(2) The species and/or stock(s) of marine mammals likely to be
found within each area;
(3) The estimated number of takes for each marine mammal stock
potentially affected in each area for the period of effectiveness of
the Letter of Authorization.
(4) If an application is for an LOA renewal, it must meet the
requirements set forth in Sec. 217.167.
(e) In the event of projected changes to the activity or to
mitigation, monitoring, reporting (excluding changes made pursuant to
the adaptive management provision of Sec. 217.97(c)(1)) required by an
LOA, Hilcorp must apply for and obtain a modification of LOAs as
described in Sec. 217.167.
(f) Each LOA must set forth:
(1) Permissible methods of incidental taking;
(2) Means of effecting the least practicable adverse impact (i.e.,
mitigation) on the species, their habitat, and the availability of the
species for subsistence uses; and
(3) Requirements for monitoring and reporting.
[[Page 12377]]
(g) Issuance of the LOA(s) must be based on a determination that
the level of taking must be consistent with the findings made for the
total taking allowable under these regulations.
(h) If NMFS determines that the level of taking is resulting or may
result in more than a negligible impact on the species or stocks of
such marine mammal, the LOA may be modified or suspended after notice
and a public comment period.
(i) Notice of issuance or denial of the LOA(s) must be published in
the Federal Register within 30 days of a determination.
Sec. 217.167 Renewals and modifications of letters of authorization
and adaptive management.
(a) An LOA issued under Sec. Sec. 216.106 of this chapter and
217.166 for the activity identified in Sec. 217.160(c) may be renewed
or modified upon request by the applicant, provided that the following
are met:
(1) Notification to NMFS that the activity described in the
application submitted under Sec. 217.160(a) will be undertaken and
that there will not be a substantial modification to the described
work, mitigation or monitoring undertaken during the upcoming or
remaining LOA period;
(2) Timely receipt (by the dates indicated) of monitoring reports,
as required under Sec. 217.165(C)(3);
(3) A determination by the NMFS that the mitigation, monitoring and
reporting measures required under Sec. 217.165(c) and the LOA issued
under Sec. Sec. 216.106 of this chapter and 217.166, were undertaken
and are expected to be undertaken during the period of validity of the
LOA.
(b) If a request for a renewal of a Letter of Authorization
indicates that a substantial modification, as determined by NMFS, to
the described work, mitigation or monitoring undertaken during the
upcoming season will occur, NMFS will provide the public a period of 30
days for review and comment on the request as well as the proposed
modification to the LOA. Review and comment on renewals of Letters of
Authorization are restricted to:
(1) New cited information and data indicating that the original
determinations made for the regulations are in need of reconsideration;
and
(2) Proposed changes to the mitigation and monitoring requirements
contained in these regulations or in the current Letter of
Authorization.
(c) A notice of issuance or denial of a renewal of a Letter of
Authorization will be published in the Federal Register within 30 days
of a determination.
(d) An LOA issued under Sec. Sec. 216.16 of this chapter and
217.166 for the activity identified in Sec. 217.160 may be modified by
NMFS under the following circumstances:
(1) Adaptive management. NMFS, in response to new information and
in consultation with Hilcorp, may modify the mitigation or monitoring
measures in subsequent LOAs if doing so creates a reasonable likelihood
of more effectively accomplishing the goals of mitigation and
monitoring set forth in the preamble of these regulations.
(i) Possible sources of new data that could contribute to the
decision to modify the mitigation or monitoring measures include:
(A) Results from Hilcorp's monitoring from the previous year(s).
(B) Results from marine mammal and/or sound research or studies.
(C) Any information that reveals marine mammals may have been taken
in a manner, extent or number not authorized by these regulations or
subsequent LOAs.
(ii) If, through adaptive management, the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
will publish a notice of proposed LOA in the Federal Register and
solicit public comment.
(2) NMFS will withdraw or suspend an LOA if, after notice and
opportunity for public comment, NMFS determines these regulations are
not being substantially complied with or that the taking allowed is or
may be having more than a negligible impact on an affected species or
stock specified in Sec. 217.162(b) or an unmitigable adverse impact on
the availability of the species or stock for subsistence uses. The
requirement for notice and comment will not apply if NMFS determines
that an emergency exists that poses a significant risk to the well-
being of the species or stocks of marine mammals. Notice would be
published in the Federal Register within 30 days of such action.
Sec. Sec. 217.168--217.169 [Reserved]
[FR Doc. 2019-05781 Filed 3-29-19; 8:45 am]
BILLING CODE 3510-22-P