Rule2025-13226
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Port of Alaska Modernization Program Phase 2B: Cargo Terminals Replacement Project in Anchorage, Alaska
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
July 15, 2025
Effective
March 1, 2026
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS, upon request from the Don Young Port of Alaska (POA), hereby promulgates regulations to govern the taking of marine mammals incidental to the Cargo Terminals Replacement (CTR) project at the existing port facility in Anchorage, Alaska over the course of 5 years. These regulations, which allow for the issuance of a Letter of Authorization (LOA) for the incidental take of marine mammals during the specified activities in the specified geographical region (see Description of the Specified Activities section) during the effective dates of the regulations, prescribe the permissible methods of taking and other means of effecting the least practicable adverse impact on marine mammal species or stocks and their habitat, as well as requirements pertaining to the monitoring and reporting of such taking.
Full Text
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[Federal Register Volume 90, Number 133 (Tuesday, July 15, 2025)]
[Rules and Regulations]
[Pages 31756-31797]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-13226]
[[Page 31755]]
Vol. 90
Tuesday,
No. 133
July 15, 2025
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 the Port of Alaska Modernization Program
Phase 2B: Cargo Terminals Replacement Project in Anchorage, Alaska;
Final Rule
Federal Register / Vol. 90 , No. 133 / Tuesday, July 15, 2025 / Rules
and Regulations
[[Page 31756]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[250630-0117]
RIN 0648-BM30
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Port of Alaska Modernization
Program Phase 2B: Cargo Terminals Replacement Project in Anchorage,
Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Final rule.
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SUMMARY: NMFS, upon request from the Don Young Port of Alaska (POA),
hereby promulgates regulations to govern the taking of marine mammals
incidental to the Cargo Terminals Replacement (CTR) project at the
existing port facility in Anchorage, Alaska over the course of 5 years.
These regulations, which allow for the issuance of a Letter of
Authorization (LOA) for the incidental take of marine mammals during
the specified activities in the specified geographical region (see
Description of the Specified Activities section) during the effective
dates of the regulations, prescribe the permissible methods of taking
and other means of effecting the least practicable adverse impact on
marine mammal species or stocks and their habitat, as well as
requirements pertaining to the monitoring and reporting of such taking.
DATES: Effective from March 1, 2026 through February 28, 2031.
ADDRESSES: Electronic copies of the application and supporting
documents, the proposed rule and associated public comments, as well as
a list of the references cited in this document, may be obtained online
at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization">https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization</a>. In case of problems accessing these documents, please
call the contact listed below.
FOR FURTHER INFORMATION CONTACT: Cara Hotchkin, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Purpose of Regulatory Action
These regulations, promulgated under the authority of the Marine
Mammal Protection Act (MMPA) (16 U.S.C. 1361 et seq.), establish a
framework for NMFS to authorize the take of marine mammals incidental
to construction activities associated with the CTR project (Phase 2B of
the POA's Modernization Program) in Anchorage, Alaska.
Legal Authority for the Action
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs
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
for up to 5 years if, after notice and public comment, the agency makes
certain findings and promulgates 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 Mitigation section), as well
as monitoring and reporting requirements.
Summary of Major Provisions Within the Rule
Following is a summary of the major provisions of this rule
regarding POA's activities. These measures include:
<bullet> Prescribing permissible methods of taking of small numbers
of 7 species (10 stocks) of marine mammals by Level B harassment, and
for a subset of those (6 species comprising 9 stocks) by Level A
harassment, incidental to the CTR project;
<bullet> Monitoring of the construction areas to detect the
presence of marine mammals before beginning construction activities;
<bullet> Establishment of shutdown zones equivalent to the
estimated Level B harassment zone for Cook Inlet beluga whales (CIBW);
<bullet> Establishment of shutdown zones for other species;
<bullet> Use of bubble curtains for all impact and vibratory
driving of permanent (72-inch (in) (1.83 meter (m)) piles in more than
3 m of water depth in all months;
<bullet> Soft start for impact pile driving to allow marine mammals
the opportunity to leave the area prior to beginning impact pile
driving at full power; and
<bullet> Submittal of monitoring reports, including a summary of
marine mammal species and behavioral observations, construction
shutdowns or delays, and construction work completed.
Through adaptive management, the regulations will allow NMFS Office
of Protected Resources to modify (e.g., remove, revise, or add to) the
existing mitigation, monitoring, or reporting measures summarized above
and required by the LOA.
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 promulgated or an incidental harassment authorization is issued.
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). If such findings are made, NMFS must prescribe
permissible methods of taking; other ``means of effecting the least
practicable adverse impact'' on the affected species or stocks and
their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance, and on the availability of
the species or stocks for taking for certain subsistence uses (referred
to in shorthand as ``mitigation''); and requirements pertaining to the
monitoring and reporting of the takings. The definitions of all
applicable MMPA statutory terms cited above are included in the
relevant sections below.
Summary of Request
On January 3, 2023, NMFS received a request from the POA for
regulations and a subsequent LOA to take marine mammals incidental to
construction activities related to the POA Modernization Program (PAMP)
Phase 2B: CTR project at the POA in Anchorage, Alaska. NMFS provided
comments on the application on March 3, 2023 and provided additional
comments to POA in response to new information on April 20, 2023 and
May 18, 2023. After POA submitted a revised application on October 13,
2023 and responded to additional questions sent on December 20, 2023,
NMFS determined the application was adequate and complete on February
12, 2024.
On March 4, 2024, we published a notice of receipt (NOR) of
application in the Federal Register (89 FR 15548),
[[Page 31757]]
requesting comments and information during a 30-day public comment
period related to the POA's request. We received 1 comment letter from
the Center for Biological Diversity (CBD) and considered the comments
in that letter during development of the proposed rule. On October 28,
2024, we published the proposed rule in the Federal Register (89 FR
85686) and requested comments and information from the public. NMFS
reviewed the submitted material and considered it for promulgation of
these regulations.
Description of the Specified Activities
The POA, located on Knik Arm in upper Cook Inlet, was constructed
primarily in the 1960s and is currently in poor condition and
substantially past its initial design life. The CTR project includes
construction of two new terminals (T1 and T2), which include planned
wharves and access trestles. The two new terminals will be located 140
feet (ft) (42.7 m) seaward of the existing general cargo terminals (T1,
T2, and T3). The CTR project also includes demolition of the existing
Petroleum, Oil, and Lubricants Terminal 1 (POL1) and T1, T2, and T3.
In-water pile installation will include both temporary (24-in (0.61m)
or 36-in (0.91 m)) and permanent (72-in (1.83 m)) steel pipe piles by
impact and vibratory hammers. Removal of temporary piles (24- or 35-in)
and existing structures (16-in (0.41 m) to 42-in (1.07 m) steel pipe
piles) will be primarily by cutting; dead-pull and vibratory extraction
methods may also be used. Existing piles may also be left standing in
their current positions. In-water work associated with the CTR project
will include installation of approximately 275 permanent piles and 450
temporary piles and vibratory extraction of approximately 46 temporary
piles. Work will occur on approximately 337 nonconsecutive days between
the months of March and November in 2026 through 2030. The specified
geographical region encompasses the land occupied by the POA, as well
as the shoreline and waters extending from the POA across Knik Arm,
northeast towards Wasilla, and southwest towards Fire Island and the
Little Susitna River delta.
A detailed description of the specified activities is provided in
the proposed rule (89 FR 85686, October 28, 2024). Since that time, POA
has not modified their planned activities. Please refer to the proposed
rule (89 FR 85686) for more information on the specified activities.
Comments and Responses
NMFS published the proposed rule in the Federal Register on October
28, 2024 (89 FR 85686), beginning a 30-day comment period. It
described, in detail, the POA's specified activities, the marine mammal
species that may be affected by the activities, and the anticipated
effects on marine mammals. In that document, we requested public input
on the request for authorization described therein, our analyses,
preliminary determinations, and the proposed regulations and requested
that interested persons submit relevant information, suggestions, and
comments.
During the 30-day public comment period, NMFS received comments
from the POA, the Alaska Department of Fish and Game (ADF&G), the CBD,
Friends of Animals, and five anonymous members of the public. After
conclusion of the comment period on January 1, 2025, we received an
additional comment from Chickaloon Village Traditional Council (CVTC).
Our responses to relevant substantive comments are below. We have not
responded to comments that failed to raise a significant point for us
to consider (e.g., comments that are out of scope of the proposed rule
or that call for mitigation, monitoring, or reporting measures already
included in the proposed rule). Furthermore, if a comment received was
unclear, NMFS does not include it here as it could not determine
whether it raised a significant point for NMFS to consider. The
comments and recommendations are available online at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization">https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization</a>. Please see
the comment submissions for full details regarding the recommendations
and supporting rationale.
Comment 1: ADF&G commented that CIBW are ``known to travel into
Knik Arm to forage, particularly in the months of June through
August.'' ADF&G suggests that activities taking place in these months
should be temporarily halted while CIBW are ``in proximity,'' and notes
that it supports the use of ``certified marine mammal observers.''
Response: NMFS agrees that shutdowns of certain activities when
marine mammals enter specified areas where they may be impacted and the
use of approved Protected Species Observers (PSO) are appropriate and
essential mitigation measures for the POA's activities and are included
in the suite of prescribed mitigation measures for these Incidental
Take Regulations (ITR). While ADF&G does not define what they mean by
``in proximity,'' pile driving at the CTR project will be required to
temporarily shut down in all months when CIBWs approach or are observed
within the modeled Level B harassment isopleths (see Mitigation
section). We note that CIBW presence in Knik Arm is highest during the
months of August through October (McGuire et al. 2020; Castellote et
al. 2020), rather than June through August as suggested by ADF&G.
Comment 2: The POA submitted a letter stating that the combined
effects of certain proposed mitigation measures, specifically
requirements to (1) employ a bubble curtain during vibratory temporary
pile driving and extraction during the months of August through October
and (2) shut down when CIBWs enter the predicted Level B harassment
zone ``will create undue hardship'' to the CTR project. POA also
asserts that these measures offer ``no proven added benefit'' for CIBW
and that additional time required for implementation of these measures
will prevent the completion of the CTR project on time, increasing the
risk of a critical facility failure. The letter states that the North
Extension Stabilization--Phase 1 (NES1) project faced significant
delays associated with shutdown requirements during the 2024
construction season due to high CIBW presence. The POA requests that
NMFS either (1) remove the requirement to use a bubble curtain during
vibratory driving of temporary piles in the months of August through
October, or (2) incorporate consideration of frequency sensitivity to
its calculations of estimated Level B harassment isopleths. The POA
states that use of the bubble curtain would differentially affect
frequency content to which CIBW are more sensitive and, therefore,
estimated Level B harassment isopleths would be smaller than calculated
by NMFS (see Comment 3).
Response: NMFS agrees, in part, with the POA's comments. The
proposed mitigation requirement at issue was for the use of bubble
curtains during vibratory driving of temporary piles in the months of
historically high CIBW presence (August through October; bubble
curtains were not proposed for use in other months for this activity).
Other proposed mitigation requirements for CIBWs include shutdown zones
equal to the predicted Level B harassment zone and the use of bubble
curtains during all impact and vibratory driving of permanent piles in
waters deeper than 3 m in all months. Notably, the POA presents
practicability concerns regarding the likelihood of
[[Page 31758]]
increased operational impacts (i.e., financial costs and potential need
for additional construction seasons) associated with delays that may
result from increased CIBW presence. These concerns, when considered in
conjunction with the relatively lower assumed effectiveness of the
proposed requirement to use bubble curtains during vibratory driving,
lead to NMFS' determination that the POA provided a compelling
justification for modification of the proposed mitigation requirements,
as discussed below.
Sightings of CIBW at and around the POA during 2024 were between 53
and 330 percent higher than the prior construction period for the
Petroleum and Cement Terminals (PCT) project in 2020-2021 in the months
of June, July, and August. Pile driving activities associated with the
NES1 project were shut down or delayed for a total of 228.5 hours over
the course of the construction season, equivalent to nearly 23 ten-hour
workdays. This increase relative to expectations in time lost to
shutdowns was due in part to delays in starting the NES1 project that
pushed the start of construction from April to the end of May, when
CIBW presence is higher. However, NMFS acknowledges that increased
occurrence of CIBW at the site during the early summer contributed to
unanticipated project delays. Reasons for the increased CIBW presence
at and around the POA are uncertain at this time but could include
changes to prey availability throughout upper Cook Inlet or other
factors and may persist into the time period covered by this rule. NMFS
acknowledges the POA's concerns about the time required to deploy
bubble curtains around each pile and regarding the effectiveness of
bubble curtains at reducing sound energy in the far-field. Previous
measurements conducted at POA showed that use of the bubble curtain did
not effectively reduce actual distances to the 120 dB RMS threshold due
to the prevalence of sound energy below 100 Hz. While use of a bubble
curtain effectively reduces the sound pressure level (SPL) any marine
mammal in the CTR project area would experience from any sound source,
the use of a bubble curtain during vibratory pile driving is not
common. Bubble curtains are most effective at reducing the injurious
components of impulsive sounds, including sharp rise times and high
peak pressures associated with impact pile driving (CALTRANS, 2020).
While they can be used to reduce SPLs associated with continuous noise
sources, such as vibratory pile driving, the benefits to species,
including fishes and marine mammals, are fewer because of the less
injurious nature of the sound sources.
The most effective mitigation measure for CIBWs included in these
regulations is the requirement to implement a shutdown of pile driving
activities at the predicted Level B harassment isopleth during
vibratory and impact pile driving. This measure minimizes the potential
for disruption of CIBW behavioral patterns by avoiding to the extent
practicable exposure to sound exceeding harassment thresholds during
pile driving. While bubble curtains effectively reduce vibratory pile
driving noise levels at frequencies to which CIBWs are sensitive (i.e.,
frequencies over 1,000 Hz) (Castellote et al. 2014; Illingworth and
Rodkin 2021a) at any given distance, a shutdown upon occurrence of CIBW
within the estimated Level B harassment zone is the most effective way
of minimizing impacts to CIBW. For other species, while the predicted
Level A harassment zones exceed the required shutdown zones during
concurrent vibratory driving scenarios, the likelihood of these species
approaching to within 165 m of the incident piles during concurrent
driving is minimal. As documented by previous measurements of sound
propagation in Cook Inlet, broadband sound levels at the predicted
Level B harassment isopleth are driven by frequencies below 100 hertz
(Hz), which are outside of the range of CIBWs' peak hearing
sensitivity, indicating that the predicted Level B harassment zone is
likely a conservative estimate for impacts to CIBW. Additionally, as
shown by summer 2024 monitoring data and previous monitoring reports
from 2020 and 2021, unattenuated vibratory pile driving in the vicinity
of the POA does not prevent CIBW from approaching and passing the POA
(61N Environmental 2021, 2022a, 2022b, 2025). NMFS, therefore, believes
the risk that unattenuated vibratory pile driving would meaningfully
impact CIBW behavioral patterns is low.
Given the documented practicability issues that the POA referenced
in its comment letter and the other, more effective mitigation measures
required, NMFS agrees with the POA's request to remove the requirement
for the use of bubble curtains during vibratory installation and
extraction of temporary piles in the months of August through October
for the CTR project. NMFS has determined, based on the practicability
concerns presented by POA and the relatively low effectiveness of this
requirement during time periods when fewer CIBW are present at the POA,
that the prescribed mitigation measures as modified remain sufficient
to effect the least practicable adverse impact on the affected marine
mammal stocks.
Comment 3: The POA stated that calculation of the estimated Level B
harassment isopleths should account for the hearing sensitivity of
beluga whales. The POA suggested that NMFS apply the weighting
functions used in the 2024 Updated Technical Guidance to the analysis
of the Level B isopleths to reflect the reduction in sound energy
expected at certain frequencies that belugas are sensitive to as a
result of employing a bubble curtain during vibratory pile driving of
temporary piles.
Response: As noted by the POA, the estimated Level B harassment
distances for sound from pile driving activities are based on
unweighted broadband sound levels. However, use of the weighting
functions recommended by POA relate specifically to the susceptibility
to noise induced hearing loss for different groups of marine mammals
and, therefore, are used for evaluation of potential auditory injury
(which falls under Level A harassment) or temporary threshold shift
(NMFS 2024). Thus, that weighting is not appropriate to consider in
evaluating the potential for behavioral harassment (which falls under
Level B harassment) as the POA recommends. Beluga hearing measurements
indicate they can detect sounds from 4 Hz to 130 kilohertz (kHz)
(Southall et al. 2019) and vibratory pile driving sound is thus within
the hearing range of this species. Even assuming use of a broader
weighting function that is more appropriate for consideration with
behavioral harassment (Southall et al. 2007), only a minimal reduction
would occur (e.g., less than -5 dB weighting at 100 Hz). Therefore,
NMFS does not agree with the POA's recommendation to reduce the size of
the shutdown zones based on the POA's approximations of beluga hearing
sensitivity.
Comment 4: The CBD asserts that NMFS' small numbers determination
is arbitrary, unlawful, unreasonable, and improper. It states that
NMFS' determination is based on an unlawful interpretation of what
constitutes a small number that is contrary to the plain meaning of the
phrase and NMFS failed to consider the species' endangered status.
Response: NMFS has provided a reasoned approach to small numbers,
as described in full in the final rule, ``Taking Marine Mammals
incidental to Geophysical Surveys Related to Oil and Gas Activities in
the Gulf of Mexico'' (86 FR 5322, 5438, January 19, 2021). NMFS makes
its small numbers findings
[[Page 31759]]
based on an analysis of whether the number of individuals authorized to
be taken annually from a specified activity is small relative to the
most appropriate estimate of stock size. CBD cites NRDC v. Evans, 279
F.Supp. 2d 1129 (N.D. Cal. 2003) to support its position. However,
CBD's reading of that case is inaccurate. In Evans, the court ruled
that the negligible impact determination and the small numbers analysis
must be undertaken separately, but the court specifically ``does not
require defendants to set an absolute numerical limit'' for small
numbers (Id. at 1152). Following that case, NMFS undertook separate
small numbers findings from its negligible impact determinations,
analyzing in each case whether the numbers were small relative to the
stock or population size (the ``proportional approach'').
We note that in this final rule, based on the best available
scientific information for CIBW occurrence in the CTR project area
(i.e., NES1: POA Construction Monitoring 61N Environmental, 2025), the
number of estimated takes of CIBWs increased from 90 to 118, amounting
to 35.6 percent of the stock if each take accrued to a new individual
(table 19). While NMFS typically presumes that each take is of a
different individual, in this case, due to the CTR project location and
feeding grounds in the upper Arm near Eagle Bay, we expect some
individuals could be taken more than once. Thus, the actual number of
individuals affected is expected to be fewer than 118 and the maximum
annual number of animals taken from this stock is considered small
relative to the relevant stock's abundance.
We disagree with CBD's assertion that NMFS' small number
determination for CIBWs should consider the status of the species. The
argument to establish a small numbers threshold on the basis of stock-
specific context is unnecessarily duplicative of the required
negligible impact finding, in which relevant biological and contextual
factors are considered in conjunction with the number of takes and
would conflate the two distinct standards (see NRDC v. Evans, 279
F.Supp. at 1153).
Comment 5: CBD contends that NMFS's small numbers and negligible
impact determinations are arbitrary because NMFS failed to evaluate the
finding that noise from tugboats and cargo/tanker vessels are the
highest noise threats to CIBWs according to NMFS' Recovery Plan for
CIBWs (NMFS, 2016). CBD further states that NMFS failed to account for
take from all project activities, including soft starts.
Response: NMFS' Recovery Plan (NMFS, 2016) ranks noise from
tugboats and cargo/tanker vessels as the most important sources that
could potentially interfere with CIBW recovery based on signal
characteristics and spatio-temporal acoustic footprint. Specifically,
NMFS (2016) identified propeller cavitation (the formation of bubbles
in a liquid) and engine noise including azimuth/bow thruster noise from
tugboats as concerning. However, notably, the Recovery Plan is
referencing vessel noise as a whole across all vessels and the entirety
of Cook Inlet, not POA's specified activity in the specified geographic
region (i.e., a heavily utilized port), which is a small portion of
overall tugboat use in Cook Inlet throughout the year.
As described in the proposed rule (89 FR 85686, October 28, 2024)
and this final rule, the POA is an industrialized area that regularly
sees traffic from vessels ranging in size from a few meters to large
cargo ships that dock and move cargo at the POA. Tugboats are required
to assist in docking larger vessels and moving barges and construction
equipment in the vicinity. As such, vessel noise is and has been part
of the soundscape in Knik Arm at least since the opening of the POA
facility on the same site in 1961 while the decline in the CIBW stock
did not begin until the 1990s (NMFS 2016). The sound source levels of
vessel activities range widely according to the type of vessel, and
level of operational effort, with full power output and higher speeds
generating more propeller cavitation and hence greater sound source
levels than lower power output and lower speeds. Vessel movement around
the POA is typically slow due to the needs of port operations, high
vessel traffic, and a narrow navigational channel. The vessels required
to support pile driving and extraction activities during the CTR
project would be similar in type to those already operating at the POA
during previous construction projects (i.e., Petroleum and Cement
Terminals (PCT), South Floating Dock (SFD), and NES1), and would not
add significantly to the average sound levels from previous summer
seasons during which CIBW continued to frequent Knik Arm and the
general vicinity of the port (61N Environmental, 2021, 2022a, 2022b,
2025). It is important to note that there are multiple contextual
factors (including the signal characteristics (i.e., impulsivity,
intensity, frequency, and duration) and the spatio-temporal (i.e.,
space and time) acoustic footprint of POA's activity as well as bearing
and distance, predictability of source movement, and likelihood of
habituation to routine vessel traffic) that minimize the likelihood of
behavioral disturbance even if a marine mammal is exposed to elevated
sound levels relative to background sound levels. CIBWs regularly
approach and pass the POA during normal port operations and during
previous construction and dredging operations. While they are exposed
to sounds from vessel traffic, the POA represents a small and
relatively low-quality portion of the habitat, and the typical
behaviors seen in the area are traveling and milling (61N Environmental
2020, 2021a, 2021b, 2025; Easley-Appleyard and Leonard 2022). No
measurable increase in vessel traffic is expected at the POA as a
result of the CTR project (POA 2024). Take by Level B harassment as a
result of vessel noise is not considered reasonably likely to occur
based on the long-term industrial nature of the area and the similarity
of the expected vessel noise sources (i.e., tugboats, barges, and small
support vessels) to the existing vessel noise (i.e., tugboats, barges,
support vessels, and container ships) at the POA.
Additionally, the NMFS Alaska Regional Office's (AKRO) Biological
Opinion under section 7 of the Endangered Species Act (ESA), which
addressed the impacts of the CIBW take NMFS is authorizing in the
context of both the environmental baseline and the cumulative effects
(including vessel noise), found that it is not likely to jeopardize the
continued existence of CIBWs or to destroy or adversely modify their
designated Critical Habitat.
CBD states that NMFS failed to analyze potential take by Level B
harassment from soft starts, a required mitigation measure during
impact pile installation. Soft starts are required, among other
reasons, to minimize the chances of injurious Level A harassment during
exposure to impulsive sounds by first introducing lower-level sounds to
the environment, allowing animals to move away from the sound source
before the hammer energy increases to full power. In the case of CIBW,
the shutdown zone established at the threshold for Level B harassment
exceeds the predicted Level A harassment zone in all cases, and pile
driving work (including soft starts) would be delayed upon observation
of a CIBW approaching or within the shutdown zone. Thus, no Level B
harassment of CIBW is expected from soft starts. For other marine
mammal species, the predicted Level A harassment zone from impact
driving of 72-in piles exceeds the Level B harassment and established
shutdown
[[Page 31760]]
zone thresholds. Exposure during a soft-start procedure would occur
within the predicted Level A harassment zone, and observations of
animals within the Level A harassment zone during a soft-start and or
subsequent impact driving would be recorded as a potential take by
Level A harassment.
Comment 6: Friends of Animals states that the proposed rule
underestimates the effects of noise from the CTR project because NMFS
did not consider the unlikely scenario of a third ``spread'' (i.e.,
construction crew and associated equipment) of construction equipment
working simultaneously at the POA during the CTR project.
Response: As stated in the POA's application and the proposed rule,
POA plans to operate no more than two vibratory hammers simultaneously.
POA does not anticipate concurrent driving using three spreads for
several reasons. First, the construction sequencing for pile
installation and extraction involves long periods of equipment
positioning, pile placement, bubble curtain placement (when required),
and short periods of active pile driving. Pile sequencing requires that
temporary piles are installed as a template, then larger permanent
piles are installed, and then the temporary piles are removed. This
required sequence plays out many times in this order during the
construction season.
Comment 7: CBD and Friends of Animals assert that NMFS' negligible
impact determination is improper and arbitrary because it fails to
account for ``harassment by noise,'' including vessel noise, in-water
pile cutting, onshore demolition, and other construction activities
that generate noise and that NMFS has no rational basis for concluding
that the take proposed for authorization has no greater than a
negligible impact on the species. CBD also asserts that NMFS's
negligible impact determination is improper because it fails to
consider cumulative impacts from other phases of the PAMP.
Response: As described in the Description of Specified Activities
section of the proposed rule (89 FR 85686, October 28, 2024), NMFS does
not expect take of marine mammals from these activities because of the
industrialized soundscape of the Port. CBD has not provided additional
information for NMFS to consider to support its claim that take will
occur from these activities. Furthermore, in the Negligible Impact
Analysis and Determination section of the proposed rule and this final
rule, we describe how the take estimated and authorized for POA's
construction activity will have a negligible impact on all of the
affected species or stocks, including CIBWs. We discuss how this
determination is based upon, among other things, the number of takes of
each stock that might be exposed to increased noise in each year and
over the course of the 5-year ITR, the comparatively low intensity of
behavioral harassment that might result from an instance of take that
could occur within that year, and the likelihood that the mitigation
measures required further lessen the likelihood, magnitude, or severity
of exposures.
NMFS' negligible impact finding considers a number of parameters
including, for example, the nature of the activities (e.g., duration,
sound source), effects/intensity of the taking, the context of takes,
and mitigation. For CIBWs, NMFS considered data from previous similar
construction activities, including previous phases of the PAMP. POA's
previous monitoring efforts have yielded data showing that CIBWs
continue to transit past the POA in construction seasons, and that
behavioral responses to noise include reduced vocalizations, faster
swim speeds, and increased group cohesion (61N Environmental 2020,
2021a, 2021b, 2025; Easley-Appleyard and Leonard 2022). Any disturbance
that may occur is anticipated to be limited to behavioral changes such
as increased swim speeds, changes in diving and surfacing behaviors,
and alterations to communication signals, not the loss of foraging
capabilities or the abandonment of critical habitat. Given these
anticipated impacts, none of which would be expected to impact the
fitness or reproduction of any individual marine mammals, much less
adversely impact annual rates of recruitment or survival of CIBWs,
NMFS' independent evaluation of the best scientific evidence in this
case supports our negligible impact determination.
Neither the MMPA nor NMFS' implementing regulations require
consideration of the take resulting from other activities in the
negligible impact analysis. The preamble for NMFS' implementing
regulations (54 FR 40338, September 29, 1989) states, in response to
comments, that the impacts from other past and ongoing anthropogenic
activities are to be incorporated into the negligible impact analysis
via their impacts on the baseline. Consistent with that direction, NMFS
has factored into its negligible impact analysis the impacts of other
past and ongoing anthropogenic activities via their impacts on the
baseline. The preamble of NMFS' implementing regulations also addresses
cumulative effects from future, unrelated activities. Such effects are
not considered in making the negligible impact determination under
section 101(a)(5) of the MMPA. NMFS considers: (1) cumulative effects
that are reasonably foreseeable when preparing a National Environmental
Policy Act (NEPA) analysis; and (2) reasonably foreseeable cumulative
effects under section 7 of the ESA for ESA-listed species, as
appropriate. Accordingly, our analysis under NEPA in the final EA and
consultation under Section 7 of the ESA does consider the cumulative
impacts from nearby activities, including past and future phases of the
PAMP. Further, the ESA Biological Opinion concluded that the CTR
project is not likely to jeopardize the continued existence of CIBWs or
to destroy or adversely modify designated CIBW critical habitat.
Comment 8: CBD asserts that NMFS's negligible impact determination
for all species relies on mitigation measures that depend upon the
efficacy of visual monitoring measures that it claims are unreliable in
Cook Inlet. CBD states that NMFS failed to acknowledge the difficulty
of visually observing marine mammals via traditional aerial and boat-
based surveys in year-round conditions.
Response: NMFS disagrees that the mitigation and monitoring
measures are ineffective, and CBD provides no additional information to
support its claim. CBD's comment focuses on Cook Inlet as a whole as
opposed to Knik Arm where the POA has a demonstrated history of
successfully implementing a rigorous monitoring program during recent
construction projects (i.e., PCT, SFD, and NES1). Monitoring data from
these projects provides evidence that their PSOs are capable of
observing CIBWs out to 11,138-m from the CTR project site under good
conditions, which is greater than any of the shutdown zones included in
this rulemaking. Additionally, POA must delay pile installation if PSOs
cannot effectively monitor the CIBW shutdown zone (i.e., the largest
shutdown zone) due to environmental conditions.
The proposed rule (89 FR 85686, October 28, 2024) and this final
rule incorporate mitigation measures that are similar or identical to
the measures required during the previous successful monitoring
efforts. Additionally, the regulations require pile driving efforts to
pause after completion of the current pile segment if weather or other
conditions prevent PSOs from effectively observing the entire shutdown
zone. These regulations require a minimum of four PSO stations and that
at each station, at least two PSOs must be on watch at any given time.
Further, the PSO stations must be
[[Page 31761]]
located so that the PSOs can fully monitor the shutdown zones and call
for activities to be delayed when CIBWs are entering or observed within
the Level B harassment zones. Observers will be positioned on stable
land-based platforms, with suitable equipment, and will not be
attempting to detect CIBWs in weather conditions deemed hazardous or
which obscure the shutdown zones. Ice floes may occasionally be
observed at the beginning and end of the construction season but are
unlikely to significantly interfere with visual observations because
construction work is impeded by ice and would not occur in conditions
with high levels of ice.
NMFS has considered realistic assumptions of PSO effectiveness
based on the precise configuration of the POA's visual monitoring
program, as demonstrated during the PCT, SFD, and NES1 projects (61N
Environmental, 2020, 2021a, 2021b, 2025). As part of the estimated take
calculations for CIBW, NMFS first calculated the estimated take in the
absence of mitigation measures and then applied a correction factor
based on the most conservative estimate of potentially realized takes
(68 percent) (61N Environmental 2025) from previous monitoring reports.
The effectiveness of PSOs has thus been included in our analysis in
both the proposed and final rules. This correction factor was not
applied to other species authorized for take.
NMFS's Negligible Impact Determination relies on required
mitigation measures being implemented by PSOs in order to limit the
amount of noise to which CIBW may be exposed. Given the sizes of
injurious (i.e., Level A harassment) and behavioral (i.e., Level B
harassment) harassment zones in relation to the demonstrated visual
range of PSOs, NMFS remains confident that the POA will effectively
reduce the potential for exposure to noise sufficient to cause Level A
harassment to zero. While PSOs may not spot some whales before they
enter the Level B harassment zone, the intensity of take by Level B
harassment is expected to be low, consisting of, at worst, temporary
modifications in behavior while the whales transit through the area
around POA on their way to foraging grounds in upper Knik Arm or out
into greater Cook Inlet. Therefore, NMFS does not anticipate adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects).
Comment 9: CBD and Friends of Animals assert that NMFS should defer
authorization of incidental take of CIBWs unless and until NMFS has a
better understanding of the reasons the species is failing to recover.
They state that until it does so, NMFS has no rational basis for
concluding that any number of take constitutes a ``negligible impact''
to the species.
Response: NMFS shares the commenters' concern regarding the impacts
of human activities on CIBWs and is committed to supporting the
conservation and recovery of the species in accordance with its
statutory responsibilities. However, section 101(a)(5)(A) of the MMPA
requires upon request by U.S. citizens for NMFS, as delegated by the
Secretary of Commerce, to allow the incidental taking of small numbers
of marine mammals if it makes the necessary findings, which includes
negligible impact. 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).
Based on the best scientific evidence available, NMFS determined
that the take, which is by Level B harassment only, incidental to POA's
pile installation and removal activities, which is transient and of a
generally low intensity, would have a negligible impact on CIBWs. No
mortality, serious injury, or Level A harassment incidental to pile
installation and removal activities is anticipated or authorized on
CIBWs; therefore, no population effects are anticipated. Moreover, POA
proposed and NMFS has required in these regulations a rigorous suite of
mitigation measures to affect the least practicable adverse impact to
CIBWs and other marine mammal species/stocks. The area within which
CIBWs and other marine mammals could be exposed to elevated sound
levels is limited to relatively low-quality, industrialized habitat
primarily used as a travel corridor between foraging areas. No critical
foraging grounds (e.g., Eagle Bay, Eagle River, Susitna Delta) would be
affected by sound from pile driving.
Results of recent studies provide evidence that the CIBW population
increased between 2004 and 2010, declined after 2010, and increased
again from 2016 to 2022 (Jacobsen et al., 2020; Shelden and Wade, 2019;
Warlick et al., 2024; Goetz et al., 2023). While there is some
uncertainty around CIBW population trend analyses, the results of these
four studies are consistent in showing general trends. Thus, while
Friends of Animals is correct that the status of CIBW abundance is less
than certain, recent studies, which NMFS considers the best scientific
information available, suggest the population may now be increasing
(see Goetz et al., 2023). Additional data in the coming years will help
to inform whether the recent positive trend in the CIBW population will
continue. NMFS is taking several proactive steps to help protect and
better understand the species. For more information, see NMFS' 5-year
Priority Action Plan (2021-2025) for CIBWs as part of its Species in
the Spotlight initiative (see <a href="https://www.fisheries.noaa.gov/resource/document/species-spotlight-priority-actions-2021-2025-cook-inlet-beluga-whale">https://www.fisheries.noaa.gov/resource/document/species-spotlight-priority-actions-2021-2025-cook-inlet-beluga-whale</a>).
Furthermore, the ESA Biological Opinion determined that the
issuance of the ITR is not likely to jeopardize the continued existence
of CIBWs or to destroy or adversely modify CIBW critical habitat. The
Biological Opinion also outlined Terms and Conditions and Reasonable
and Prudent Measures to reduce impacts, which have been incorporated
into the regulations.
Comment 10: CBD commented that NMFS fails to ensure the least
practicable adverse impact on CIBWs, the other species or stocks to be
taken, and their habitats because NMFS failed to consider requiring
several practicable mitigation measures. Friends of Animals recommended
that NMFS should require more rigorous mitigation measures but did not
provide any examples of such measures.
Response: NMFS has included a suite of mitigation measures designed
to effect the least practicable adverse impact on marine mammal species
and their habitat and has also included appropriate monitoring and
reporting requirements. Prior to starting pile driving activities, POA
must conduct pre-clearance monitoring and may only commence activities
once the shutdown zones have been monitored for 30 minutes and
determined clear of marine mammals. At the start of pile driving, POA
must use soft start techniques for impact pile driving (note that soft
starts are considered ineffective for vibratory pile driving due to the
non-impulsive nature of the sound source). During pile driving
activities, POA must employ bubble curtains to reduce noise output in
waters deeper than 3 m during all impact pile driving and during
vibratory pile driving of permanent piles. If a marine mammal is
observed within the shutdown zone, POA is required to halt activities
until the animal has voluntarily left or has not been observed for
species-specific time periods. Please see the Mitigation section of
this final rule for a full description of the required mitigation
measures.
[[Page 31762]]
Additional noise mitigation methods proposed by CBD included pile
caps, dewatered cofferdams, and other physical barrier mitigation. NMFS
does not consider pile caps an effective noise mitigation method
because pile caps are used to protect piles and equipment during impact
pile driving. They are typically made of wood or plastic and are
designed to compress and fracture during use, limiting their
consistency with respect to noise mitigation and potentially leading to
safety issues if replaced during hammer operations (CALTRANS 2020).
Additionally, because pile caps are used during most impact driving,
any noise mitigation from caps is included in measured source values
and proxy source values used in our analysis. Dewatered cofferdams are
impracticable due to space restrictions in and around the POA, as well
as the extreme environmental conditions in Knik Arm, including high
tidal ranges and current velocities, as well as the unpredictable
nature of ice movement during winter months. NMFS is not aware of other
``physical barrier mitigation'' methods that have been used during
coastal construction projects, and CBD did not provide further
examples.
CBD also stated that NMFS failed to consider the least practicable
adverse impact to beluga whale habitat in Cook Inlet but neither
provides any specific examples of adverse habitat impacts nor suggested
mitigation measures. NMFS acknowledges that a minimal amount of low-
quality habitat will be lost due to the expansion of the terminal
footprint and that water-column noise levels will be increased during
construction. While most of the physical and biological features
essential to the CIBW critical habitat are found at the POA, and CIBW
Biologically Important Area (BIA) includes the waters around the POA,
this area represents a very small portion of the overall habitat
available and is not known to be an important foraging or resting site
for this stock (61N Environmental 2020, 2021a, 2021b, 2025). We
anticipate minimal impacts to prey or other habitat features as
outlined in the proposed rule (89 FR 85686; October 28, 2024) and this
final rule.
Comment 11: CBD commented that NMFS fails to ensure the least
practicable adverse impact on CIBWs, the other species or stocks to be
taken, and their habitats because NMFS failed to consider requiring the
use of passive acoustic monitors (PAM) as a way to evaluate at the end
of the construction activities (seasonal or comprehensive) whether
CIBWs or other marine mammals went undetected by PSOs during visual
monitoring.
Response: NMFS agrees that archival PAM data would be useful in
evaluating the presence of CIBWs at the POA and the effectiveness of
the PSOs during times of visual observations. While some CIBWs and
other marine mammals may not be detected by PSOs before entering the
shutdown zones (61N Environmental, 2020, 2021a, 2021b, 2025), the
design and deployment of the PAM systems and data analysis is too time-
and cost-intensive to be practicable to the POA. An article on NOAA's
website illustrates the level of customization, expertise, and
difficulty required to assemble a passive acoustic mooring suitable for
deployment in Cook Inlet (see <a href="https://www.fisheries.noaa.gov/science-blog/beluga-whale-acoustic-monitoring-survey-post-3">https://www.fisheries.noaa.gov/science-blog/beluga-whale-acoustic-monitoring-survey-post-3</a>).
Background acoustic conditions, including flow noise from strong
currents, large tidal changes, weather, and normal port operations,
along with additional noise from the project (e.g., pile driving) can
make it difficult to detect marine mammals during PAM, particularly
when the site is known to be noisy (as it is at POA). Further, the data
stored on these types of moorings is not accessible until they are
retrieved by the researcher who deployed them. Lessons learned from
prior sound source verification studies carried out at the POA (e.g.,
I&R, 2021a, 2022b) indicate that Knik Arm is a very challenging
environment in which to collect high quality acoustic data usable by
NMFS, the POA, and others due to the presence of strong tidal currents,
which can create substantial flow noise in recordings, and prevalent
anthropogenic noise, which can mask acoustic signals of interest.
Specifically, during the CTR project, multiple barges, tugboats, and
other support vessels, which can obscure signals of interest, will be
within the CTR project area at all times during the CTR project. As
mentioned in the proposed rule (89 FR 85686, October 28, 2024) with
respect to near-real-time PAM devices, the constraints of the system
design even for archival moored systems and the known challenges of the
area make PAM impracticable for the POA.
Comment 12: CBD commented that NMFS fails to ensure the least
practicable adverse impact on CIBWs, the other species or stocks to be
taken, and their habitats because NMFS failed to consider requiring
seasonal restrictions.
Response: Contrary to CBD's assertion, NMFS did consider a seasonal
restriction for this project, in addition to the PSO requirements. We
note that August through October are months with high CIBW abundance,
and NMFS expects that the POA will likely have to shut down pile
driving activities more frequently during that time period due to the
increased presence of CIBWs in Knik Arm. The POA is planning to
complete in-water work as early in the construction season as is
practicable. However, due to the scope of the CTR project and the needs
of the construction sequencing, it is not practicable to restrict pile
driving to any specific time periods or areas (e.g., only allowing pile
driving April through July or restricting vibratory driving but not
impact driving to such periods). The necessary pile sequencing requires
that temporary piles are installed as a template, then larger permanent
piles are installed, and then the temporary piles are removed. This
required sequence plays out many times, in this order, during the open
water construction season. It is therefore not possible for POA to
install all of the larger permanent piles during the early season and
install temporary piles later in the season; the larger and smaller
piles must be alternated.
Furthermore, there are potential consequences of pausing or
delaying the construction season, including de-rating the structural
capacity of the existing docks, a shutdown of dock operations due to
deteriorated conditions, or an actual collapse of one or more dock
structures. The potential for collapse increases with schedule delays,
due to both worsening deterioration and the higher probability of a
significant seismic event occurring. Any of these scenarios could have
dire consequences for the populations of Anchorage and Alaska who are
served by the POA. In this context, NMFS has determined that the
current mitigation and monitoring measures affect the least practicable
adverse impact on marine mammal species and stocks.
Comment 13: CBD commented that NMFS fails to ensure the least
practicable adverse impact on CIBWs, the other species or stocks to be
taken, and their habitats because NMFS failed to consider requiring the
use of drones to help detect the presence of marine mammals.
Response: While unmanned aerial vehicles (UAVs) (i.e., drones) have
been used in some instances to observe marine mammals, there are
logistical reasons why this measure is not practicable for POA to
implement for this project. The POA is uniquely situated adjacent to an
active military installation and airfield (Joint Base Elmendorf-
Richardson (JBER)) and in close proximity to several civilian airports,
including Ted Stevens Anchorage International Airport, Merrill
[[Page 31763]]
Field Airport, and Lake Hood Seaplane Base (the world's largest and
busiest seaplane base). As such, the surrounding airspace is complex
and heavily trafficked with general aviation, commercial (including
cargo), and military aircrafts.
Flying UAVs at the POA or over Knik Arm would require FAA approval
for four different jurisdictions of airspace in the Anchorage Terminal
Area (14 CFR part 93 Subpart D). In order to obtain permission for
drones, an event specific Notice to Airmen must be approved by the FAA
and JBER. The JBER tower requires 48-hour notice prior to launch and
100 percent phone communication during all drone activities. In
addition, the drone operator would have to be in constant communication
with each respective airspace the drone occupies as it transits between
segments over Knik Arm. Previous efforts to conduct surveys using UAV
have shown that this is not practicable.
The POA operates a robust marine mammal monitoring program that
utilizes multiple stations, big-eye binoculars, theodolites, and cloud-
based mapping among four observation stations spaced along a linear
distance of about 8.5 kilometers of coastline. It is unlikely drones
would provide additional benefit to the monitoring program. The least
practical adverse impact to CIBW and other marine mammals is thus
achieved through standard PSO requirements already included in the
proposed rule, and therefore, NMFS has not required that POA use UAVs
to assist in detecting marine mammals during their planned construction
activities.
Comment 14: CBD commented that NMFS fails to ensure the least
practicable adverse impact on CIBWs, the other species or stocks to be
taken, and their habitats because NMFS failed to consider requiring the
use of bubble curtains in all months and water depths. They stated that
NMFS should require the POA to employ confined bubble curtains during
all pile driving activities in all months and that no justification was
given for not requiring the use of a bubble curtain in waters less than
3 m deep. CVTC stated that bubble curtains should be required for all
impact or vibratory driving of any pile type (permanent or temporary)
of all pile sizes (24-, 36-, and 72-in as well as other sizes) in all
water depths (0.1 m and deeper) in all months of the year, and that
between August and October two separate and completely overlapping
layers of bubble curtains should be required, or that alternatively
impact and vibratory driving of any pile type should be prohibited
during those months.
Response: NMFS considered the practicability of requiring the POA
to use a bubble curtain in all construction months in conjunction with
the need for POA to complete most work during the beginning of
construction seasons (i.e., in the months of April-July) when CIBWs are
less likely to be present at the POA. In the proposed rule (89 FR
85686, October 28, 2024), we acknowledged the use of bubble curtains on
all piles has the potential to drive the in-water construction schedule
further into the late summer months, which are known for higher CIBW
abundance in the CTR project area, thus lengthening the duration of
potential interactions between CIBW and in-water work. Given the data
from the 2024 NES1 construction project showing increased prevalence of
CIBW near the POA and the resulting delays in construction due to work
shutdowns (see Comment 2 and Response, above), NMFS determined that use
of a bubble curtain for all piles in all months may ultimately result
in increased impacts to CIBW by lengthening the total duration of the
CTR project over additional years. This final rule maintains the
requirement for POA to utilize a bubble curtain during all impact and
vibratory driving of permanent 72-in piles in waters deeper than 3 m in
all months, reducing the likelihood of auditory injury to all marine
mammal species, particularly those for which the Level A harassment
isopleth may exceed the shutdown zone. The least practicable adverse
impact to CIBW and other marine mammals is thus achieved without
requiring the use of bubble curtains during vibratory pile driving.
Bubble curtains may be used at the POA and contractor's discretion.
With respect to the depth constraint specified in the proposed ITR,
designing a bubble curtain that can handle the rapid rise and fall of
the tides is infeasible. The average tidal range in Knik Arm is about 8
m (26 ft) and can be as great as 10.7 m (35 ft) (Lipscomb 1989). This
means that when the tide level changes from low to high or from high to
low, which takes about 5 hours and 15 minutes, the rate of change can
be 1.5 to 2 vertical m (5 to 6.7 ft) per hour. Such a rapid increase
and decrease in tide level makes it impossible to increase or decrease
the number of rings and keep a bubble curtain system operating under
water with full air flow and pressure. If an air hole is above water,
it will create an easier route for air release and compromise the air
pressure in the entire system. The POA encourages the contractor to
install and remove piles at low tide or in the dry, when possible,
which greatly reduces sound pressure levels in water. The 3 m cutoff
for use of a bubble curtain gives contractors some flexibility to
complete a pile installation under rapidly changing conditions.
Similarly, the design of the bubble curtain required for impact and
vibratory driving of permanent piles is at the discretion of the
contractor for the CTR project. While POA used a confined bubble
curtain during the first year of the PCT project, there were
significant financial expenses associated with the design and time
delays required for operations that were reduced with the use of an
unconfined system during the second year of the PCT project. Confined
and unconfined bubble curtain systems required an average of 6 and 4
hours, respectively, for deployment and retrieval operations.
Utilization of a double bubble curtain, as recommended by CVTC, would
increase the costs and delays associated with single curtains.
Additionally, requirements for more equipment increase safety concerns
associated with deck space on work barges and maneuvering space in and
around the POA and the construction site. Therefore, it is
impracticable for the POA to implement these suggested mitigation
measures except at the discretion of the contractor.
Comment 15: CBD states that NMFS should prepare programmatic NEPA
and ESA analyses for its CIBW take authorizations. CBD states that at a
minimum, NMFS should analyze the PAMP in a single NEPA and ESA review
that considers all cumulative, indirect, and direct environmental
effects.
Response: NMFS originally declared its intent to prepare an EIS for
take authorizations in Cook Inlet, Alaska (79 FR 61616, October 14,
2014). However, in a 2017 Federal Register notification (82 FR 41939,
September 5, 2017), NMFS indicated that in part due to a reduced number
of incidental take authorization requests in the region, we were
postponing any potential preparation of an EIS for take authorizations
in Cook Inlet. As stated in the 2017 Federal Register notice, NMFS
should the number of ITA requests, or anticipated requests, noticeably
increase, NMFS will re-evaluate whether preparation of an EIS is
necessary. Currently, the number of ITA requests for activities that
may affect marine mammals in Cook Inlet is at such a level that
preparation of an EIS is not appropriate. Nonetheless, under NEPA, NMFS
is required to consider cumulative effects of other potential
[[Page 31764]]
activities in the same geographic area, and these are discussed in
greater detail in the Final EA prepared for this promulgation of an ITR
to the POA for the CTR project, which supports our finding that NMFS'
issuance of the POA ITR will not have a significant impact on the human
environment.
CBD asserts that NMFS should analyze the PAMP in a single NEPA
review, rather than ``segmenting'' the various PAMP phases. NMFS has
appropriately analyzed and captured all past, present and reasonably
foreseeable future actions under NEPA. This includes the projects
associated with the PAMP, which each have independent utility and
require separate authorizations and NEPA analyses. The EAs for each
PAMP activity appropriately analyze the cumulative, indirect, and
direct environmental effects of each specified action. They include an
evaluation of each action's affected area, the scale and geographic
extent of each action, and the degree of cumulative effects on
resources (e.g., the duration of impact, and whether the impacts were
adverse and/or beneficial and their magnitude) under NEPA.
NMFS can prepare an EA so long as the record supports the
conclusion that potential impacts are not ``significant'' for the
purposes of NEPA. Based on the information presented in the application
and NMFS' Policy and Procedures for Compliance with the NEPA and
Related Authorities (Companion Manual (CM) for NOAA Administrative
Order (NAO) 216-6A) (NOAA 2017), sections 3 and 7, NMFS' determination
to prepare an EA is appropriate and in compliance with NEPA, NMFS
appropriately signed a Finding of No Significant Impact (FONSI) for the
promulgation of the ITR for incidental take associated with the POA's
CTR project in support of this determination. The FONSI concluded that
NMFS' proposed action, the promulgation of an ITR and issuance of an
associated LOA to the POA, will not meaningfully contribute to
significant impacts to specific resources, given the limited scope of
NMFS' action and required mitigation measures. Accordingly, preparation
of an EIS for this action is not necessary.
With respect to ESA, while a programmatic approach streamlines the
procedures and time involved in consultations for broad agency programs
or multiple similar, frequently occurring, or routine actions with
predictable effects on listed species and/or critical habitat, it is
discretionary. This approach depends on knowing with reasonable
certainty the broad types of actions and the expected impacts to the
species. In Cook Inlet, NMFS consults on a wide variety of activities,
including coastal construction, oil and gas exploration and extraction,
research, and military readiness efforts. The variety of actions and
potential impacts is such that NMFS is unable to conduct a programmatic
Section 7 consultation for all actions that may impact CIBW. While a
programmatic consultation for similar types of actions (i.e., coastal
construction) could be considered, NMFS still lacks relevant details
such as project duration and design specifics for projects like the
PAMP, which are funded and designed in phases. The timeline for the CTR
project's funding and design, in combination with the vulnerability of
this critical infrastructure to seismic events, makes a programmatic
consultation impractical.
While a programmatic approach is currently not possible, the ESA
requires consideration of cumulative impacts during the preparation of
the Biological Opinion (BiOp). The NMFS Alaska Regional Office issued a
BiOp concluding that the take, by harassment, of CIBW, humpback whales
(Mexico-North Pacific DPS and Western North Pacific DPS), and Steller
sea lions (Western DPS) would not jeopardize the continued existence of
those stocks and the takings would not adversely modify critical
habitat. The full analysis supporting these conclusions can be found in
the BiOp (NMFS, 2025).
Comment 16: CBD and Friends of Animals believe the draft EA for the
CTR project fails to comply with the requirements of NEPA. They
stipulate that the draft EA fails to consider a reasonable range of
alternatives and to consider impacts of vessel noise associated with
the CTR project and lacks a meaningful environmental and cumulative
impacts analysis. Friends of Animals recommended that NMFS should
conduct a more comprehensive assessment of the cumulative effects
related to noise, habitat degradation, chemical exposure, mortality,
stranding, climate change, and migration of the species and its prey,
specifically mentioning potential synergistic effects of noise and
toxic chemical exposure.
Response: In accordance with the NEPA, NMFS is required to consider
a reasonable range of alternatives to a Proposed Action, as well as a
No Action Alternative. Reasonable alternatives are viable options for
meeting the purpose and need for the proposed action. The evaluation of
alternatives under NEPA assists NMFS with understanding, and as
appropriate, minimizing impacts through an assessment of alternative
ways to achieve the purpose and need for our Proposed Action.
Reasonable alternatives are carried forward for detailed evaluation
under NEPA while alternatives considered but determined not to meet the
purpose and need are not carried forward. For the purposes of this EA,
an alternative will only meet the purpose and need if it satisfies the
requirements of section 101(a)(5)(A) of the MMPA.
In accordance with NOAA's implementing procedures, the CM for NAO
216-6A, Section 6.B.i, NMFS is defining the No Action alternative as
not authorizing the requested incidental take of marine mammals under
Section 101(a)(5)(A) of the MMPA. This is consistent with our statutory
obligation under the MMPA to either: (1) deny the requested
authorization; or (2) grant the requested authorization and prescribe
mitigation, monitoring, and reporting requirements. The Preferred
Alternative (i.e., promulgation of the ITR) includes mandatory
mitigation, monitoring, and reporting requirements for POA to achieve
the MMPA standard of effecting the least practicable adverse impact on
each species or stock of marine mammal and their habitat, paying
particular attention to rookeries, mating grounds, and other areas of
similar significance. Since NMFS is required to prescribe mitigation to
effect the least practicable adverse impact on marine mammals,
mitigation that reduces impacts on marine mammals is inherently
included in Alternative 2 (the proposed action) and is included as part
of the analysis of alternative(s) in the Environmental Consequences
chapter in the EA. NMFS described both the No Action Alternative and
Preferred Alternative in the EA. We have also included an
``Alternatives Considered but Eliminated from Further Consideration''
section in the final EA that considered whether other alternatives
could meet the purpose and need while supporting this applicant's
proposal to replace the existing cargo terminals at the POA. There is
no requirement under NEPA to consider more than two alternatives or to
consider alternatives that are substantially similar to other
alternatives or which have substantially similar consequences. NMFS'
range of alternatives is based on the proposed action and the purpose
and need, which are linked to NMFS' authorities under the MMPA. For the
purposes of analysis under NEPA in the EA, an alternative will only
meet the purpose and need if it satisfies the requirements under
section 101(a)(5)(A) of the MMPA. Therefore, NMFS determined that,
based on our authorities and criteria under the MMPA, which included
[[Page 31765]]
criteria regarding mitigation measures, appropriate considerations were
applied to identify which alternatives to carry forward for analysis.
NMFS considered vessel noise as a component of the acoustic
environment in Cook Inlet and near the POA in section 3.2.3.3 of the
Draft EA. We have revised the final EA to more explicitly discuss the
potential impacts of vessel noise; however, these additions do not
change the conclusions reached in the Draft EA.
CBD asserts that NMFS ``fails to disclose or analyze the unique
threat that the cumulative effects of multiple stressors have on''
CIBWs. NMFS evaluated the cumulative impacts of multiple stressors
associated with the past, present, and reasonably foreseeable future
actions in the action area, including projects associated with other
PAMP phases, vessel noise (e.g., commercial shipping traffic and vessel
noise associated with the CTR project), vessel traffic in Knik Arm, and
research activities in Section 4.8 of the EA. Vessel operations at the
POA are not expected to measurably increase as a result of the CTR
project (POA 2024). As stated in the EA, while consideration of
activities in sum suggests an increase in industrialization of Cook
Inlet, many of the past, present, and reasonably foreseeable future
actions are spatially and temporally limited and do not permanently
reduce or degrade the habitat available to marine mammals or their prey
species. While the CTR project would add an incremental contribution to
the combined environmental impacts of other past, present, and
reasonably foreseeable future actions; those direct and indirect
adverse impacts are expected to be mainly short-term, localized, and
minor, as described in the EA. None of the take authorized by NMFS in
other ITAs would overlap in time or space with impacts from the CTR
project.
NMFS appreciates Friends of Animals' recommendation for conducting
a more comprehensive study of cumulative effects of the various
stressors on CIBW. While Friends of Animals does not provide any new
information on cumulative effects, including synergistic effects of
marine pollution and noise, this has been studied in other beluga
populations. Williams et al. (2021) found that in St. Lawrence River
belugas, the combined effects of proximate threats such as ocean noise,
prey limitation, and contaminants were less significant that the
potential threats from global climate change and the resulting expected
changes to habitat. Of note, while the Recovery Plan for the Cook Inlet
Beluga Whale cited by Friends of Animals identifies pollution as a
threat, it notes that available information indicates that the
magnitude of the pollution threat to CIBW appears low, though not all
pollutants to which CIBW are exposed have been studied in that
environment. NMFS has revised the EA to include more information on the
potential for exposure to contaminants to harm the health of CIBW.
Comment 17: CTVC states that the POA should cover the costs of
having NMFS study the noise protections offered by the bubble curtains
including during different water temperatures, sediment loads, water
currents, and other factors which may affect the protections for whales
and that NOAA NMFS and the Port of Alaska should meet annually to
discuss methods and devices for protection of whales that can be
implemented in subsequent months/years of the CTR project.
Response: Per section 101(a)(5)(A) of the MMPA, NMFS can require
holders of issued authorizations to conduct monitoring for marine
mammals during the specified activities, but it cannot require an
applicant to fund specific NMFS studies. The POA has previously
completed hydroacoustic monitoring of pile driving activities during
the PCT project, including the effectiveness of bubble curtains, as
part of required monitoring. In the proposed ITR, NMFS considered the
mitigatory value of additional hydroacoustic monitoring and determined
that more data would not significantly add to the value of the current
dataset. If POA elects to conduct hydroacoustic monitoring, NMFS will
include those data in future analyses.
Adaptive management is a key part of the ITR process (see Sec.
217.18 Modifications of Letters of Authorization of the new regulatory
text provided by this final rule). The POA submits monitoring reports
to NMFS recording marine mammal sightings during each year of the CTR
project. For the CTR project, weekly reports are required. NMFS tracks
these reports and estimates take numbers for each species during the
construction season. NMFS may modify LOA mitigation, monitoring, or
reporting measures if doing so creates a reasonable likelihood of more
effectively accomplishing the goal of the measure. Additionally, any
new technologies or methods for reducing impact on marine mammals can
be cause to update the required mitigations set forth in these
regulations.
Changes From the Proposed Rule
There have been several changes from the proposed rule in this
final rule. First, NMFS finalized the draft 2024 Updated Technical
Guidance referenced in the proposed rule on October 24, 2024 (89 FR
84872). The incorporation of this updated guidance did not change the
estimated take of marine mammals or the shutdown zones because the
proposed rule analyzed the draft Updated Technical Guidance in
anticipation of its incorporation in the final rule. Consistent with
the Updated Technical Guidance, nomenclature changes have been made to
the final rule: mid-frequency cetaceans have been re-classified as
high-frequency cetaceans, and high-frequency cetaceans have been
updated to very-high-frequency (VHF) cetaceans.
Secondly, NMFS has incorporated the most recent sighting data (from
2024) into our analysis of the sighting rate bins, and thus, the
estimated take (see tables 13 and 17 in this notice). Take estimates
for all years increased due as a result of inclusion of these updated
data in the analysis. Additionally, NMFS has concurred with the change
requested by the POA in their public comment letter (see Comment 2 and
Response, above) and removed the proposed requirement for the use of
bubble curtains during vibratory driving of temporary (24-in or 36-in)
piles, which was proposed to be implemented during the months of August
through October. The removal of the bubble curtain requirement does not
affect estimated take because attenuated and unattenuated vibratory
pile driving isopleths both occurred in the same sighting rate bin in
the estimated take analysis (see Estimated Take for more information).
Thirdly, NMFS has added the Western North Pacific (WNP) stock of
humpback whale (Megaptera novaengliae) to this rule (see table 1). The
POA did not request, and thus NMFS did not propose, take of the WNP
stock of humpback whales because few individuals from this stock are
estimated to occur in Cook Inlet (NMFS, 2025). However, as a result of
NMFS' section 7 consultation under the ESA, impacts to the WNP stock
were analyzed jointly with the impacts to the Mexico-North Pacific
stock. Estimated take for this species has not changed because take was
not delegated to stock level because it is not possible to identify
humpback whales by stock in the field. In Cook Inlet, humpback
populations are approximately 89 percent Hawaii DPS individuals, 11
percent Mexico DPS individuals, and less than one percent WNP DPS
individuals (NMFS 2025).
Finally, the regulatory text in the proposed rule omitted language
related
[[Page 31766]]
to qualifications of PSOs, which was included in the text of the rule
and a requirement that PSO data be submitted in a queryable format,
which was not. The regulatory language and text of the rule have been
revised accordingly.
There are also several typographical errors in the Proposed Rule
that are corrected in this notice. First, in the Summary of Major
Provisions Within the Proposed Rule section, the proposed rule stated
that shutdown zones for non-CIBW species would be equivalent to or
greater than the estimated Level A harassment zones. This should have
read ``Establishment of shutdown zones equivalent to or greater than
the estimated Level A harassment zones during vibratory pile driving;
and at a practicable distance during impact driving for other
species.'' The shutdown zones for non-CIBW species during impact
driving do not exceed the Level A harassment isopleths, as PSOs are
unlikely to see some species at such distances. This was accurately
described in the Mitigation section of the proposed rule.
Second, two errors were present in the ``Number of Days over 5
Years'' column in table 1 of the proposed rule. The number of days of
temporary pile installation should be 159 instead of 144, and the
number of days of temporary pile removal should be 19 instead of 15.
The correct number of days was used in the take estimation and thus
these corrections do not affect the take estimates.
Third, discussion of ensonified area within the Estimated Take
section of the proposed rule (89 FR 85686, October 28, 2024) stated
that ``for vibratory driving during the CTR Project, it is assumed that
a well-designed and robust bubble curtain system will achieve a mean
reduction of 7 dB at the source.'' This statement should have specified
that the assumption applied only to 72-in permanent piles during
vibratory driving, and that measurements of attenuated installation and
extraction of temporary (24-in and 36-in) piles were used in the
analysis.
Fourth, tables 15 and 16 of the proposed rule had an incorrect
Level B harassment distance for vibratory removal (attenuated) of a 24-
in pile; the table read 2,583 m when the correct distance is 2,089 m.
This is corrected in table 10 of this final rule.
Finally, due to a rounding error, the Level A take estimates for
harbor seals and harbor porpoise in table 25 (99 and 16, respectively)
of the proposed rule did not match the values shown in tables 21 and 22
(98 and 15, respectively). The values in tables 21 and 22 were correct.
The total maximum annual take estimates have been adjusted in table 19
of this final rule.
Description of Marine Mammals in the Specified Geographical Region
There are seven species, comprising 10 stocks, of marine mammals
that may be found in upper Cook Inlet during the proposed construction
and demolition activities. Sections 3 and 4 of the POA's application
and request for regulations summarize available information regarding
status and trends, distribution and habitat preferences, and behavior
and life history of the potentially affected species. NMFS fully
considered all of this information, and we refer the reader to these
descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs) (see <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS'
website at: <a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>.
Table 1 lists all species or stocks for which take is likely and
may be authorized for the specified activities and summarizes
information related to the population or stock, including regulatory
status under the MMPA and ESA and potential biological removal (PBR),
where known. PBR is defined by the MMPA as ``the maximum number of
animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its
optimum sustainable population'' (16 U.S.C. 1362(20)). While no serious
injury or mortality is anticipated or proposed to be authorized here,
PBR and annual serious injury and mortality from anthropogenic sources
are included here as gross indicators of the status of the species or
stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Alaska and Pacific SARs (e.g., Carretta, et al., 2023; Young
et al., 2023, 2024). Values presented in table 1 are the most recent
available at the time of publication, including from the draft 2024
SARs, and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports</a>.
Table 1--Species Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance Nbest,
ESA/ MMPA status; (CV, Nmin, most recent Annual M/
Common name Scientific name MMPA stock strategic (Y/N) abundance survey) \2\ PBR SI \3\
\1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray whale...................... Eschrichtius robustus.. Eastern N Pacific...... -/-; N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Hawaii................. -, -, N 11,278 (0.56, 7,265, 127 27.09
2020).
Mexico-North Pacific... T, D, Y N/A (N/A, N/A, 2006).. \4\ UND 0.57
Western North Pacific E,D,Y 1,084 (0.088, 1,007, 3.4 5.82
\5\. 2006).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Killer whale.................... Orcinus orca........... Eastern North Pacific -/-; N 1,920 (N/A, 1,920, 19 1.3
Alaska Resident. 2019).
[[Page 31767]]
Eastern North Pacific -/-; N 587 (N/A, 587, 2012).. 5.9 0.8
Gulf of Alaska,
Aleutian Islands and
Bering Sea Transient.
Family Monodontidae
Beluga whale.................... Delphinapterus leucas.. Cook Inlet............. E/D; Y 331 (0.076, 311, 2022) 0.62 0
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Alaska......... -/-; Y 31,046 (0.214, N/A, \4\ UND 72
1998).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
Steller sea lion................ Eumetopias jubatus..... Western................ E/D; Y 49,837 (N/A, 49,837 299 267
2022).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Cook Inlet/Shelikof -/-; N 28,411 (N/A, 26,907, 807 107
Strait. 2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a> assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\4\ UND means undetermined.
\5\ PBR in U.S. waters = 0.2, M/SI in U.S. waters = 0.06.
A detailed description of marine mammals in the specified
geographic region, including brief introductions to the species and
relevant stocks (with the exception of the WNP stock of humpback
whales), as well as available information regarding population trends
and threats, and information regarding local occurrence, were provided
in the proposed rule (89 FR 85686, October 28, 2024). Please refer to
the proposed rule (89 FR 85686, October 28, 2024) for full descriptions
of all species.
The WNP stock is fully aligned with the WNP DPS and the stock range
includes humpback whales in the Mariana Archipelago, as they are known
to be part of this DPS based on both photographic identification
matches and genetics (Hill et al. 2020). It consists of two units: the
Philippines/Okinawa--North Pacific unit and the Marianas/Ogasawara--
North Pacific unit. The units are managed as a single stock at this
time, due to a lack of data available to separately assess them (NMFS
2023a, NMFS 2019, NMFS 2022d). Recognition of these units is based on
movements and genetic data (Oleson et al. 2022). Whales in the
Philippines/Okinawa--North Pacific unit winter near the Philippines and
in the Ryukyu Archipelago and migrate to summer feeding areas primarily
off the Russian mainland (Oleson et al. 2022). Whales that winter off
the Mariana Archipelago, Ogasawara, and other areas not yet identified
and then migrate to summer feeding areas off the Commander Islands, and
to the Bering Sea and Aleutian Islands comprise the Marianas/
Ogasawara--North Pacific unit.
Since the publication of the proposed rule in October 2024, two
marine mammal entanglement or stranding events have been documented. On
October 1, 2024, PSOs working on the POA's North Extension
Stabilization (NES) project spotted a CIBW entangled in an unknown
object (possibly a tire inner-tube) near the POA (61N Environmental,
2025). The whale was sighted again on October 2 but was not seen after
that time. Video footage of the individual was taken, and the whale was
determined to be a subadult, at least 7 years old (NMFS, 2024). The
entanglement was determined to be life-threatening, but the whale was
not seen after October 2, and no disentanglement effort was possible.
This is the third known entanglement of a free-swimming CIBW; the
others were observed in 2005 and 2010. There is no evidence that the
entanglement material originated at the POA or that the pile driving
occurring at the time of the observation contributed in any way to the
entanglement or subsequent behavior. The POA implements measures to
ensure construction materials and waste products do not enter Cook
Inlet. The impacts of this entanglement were limited to the entangled
individual, and NMFS does not believe that this type of event is likely
to recur as a result of the POA's planned activities.
In November 2024, a deceased juvenile fin whale (Balaenoptera
physalus) stranded close to Anchorage. Fin whales are common in lower
Cook Inlet but uncommon in the upper inlet and the carcass is likely to
have been moved to the upper inlet by tidal currents. Therefore, while
NMFS acknowledges that there is a possibility of a fin whale
approaching Anchorage during the CTR project, we do not believe that
take of this species is reasonably likely to occur in the specified
geographic region. Fin whales were excluded from further analysis in
the proposed rule, and NMFS finds that this new information does not
influence its conclusions regarding fin whales.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical
[[Page 31768]]
modeling, etc.). Note that no direct measurements of hearing ability
have been successfully completed for mysticetes (i.e., low-frequency
cetaceans). Subsequently, NMFS (2018, 2024) 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.
On May 3, 2024, NMFS published and solicited public comment on its
draft Updated Technical Guidance (89 FR 36762), which includes updated
hearing ranges and names for the marine mammal hearing groups. This
guidance was finalized on October 24, 2024 (89 FR 84872) with no
substantive changes. In the proposed rulemaking, we considered both the
2018 and 2024 Technical Guidance in our effects and estimated take
analysis. Therefore, the estimated take analysis in the proposed rule
based on the draft 2024 Technical Guidance incorporates the best
available scientific information and is carried forward in this final
rule. Table 2 shows the updated hearing groups included in the 2024
Updated Technical guidance.
Table 2--Marine Mammal Hearing Groups
[NMFS 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
UNDERWATER: .................................
Low-frequency (LF) cetaceans 7 Hz to 36 kHz.
(baleen whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales,
beaked whales, bottlenose
whales).
Very High-frequency (VHF) 200 Hz to 165 kHz.
cetaceans (true porpoises,
Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) 40 Hz to 90 kHz.
(underwater) (true seals).
Otariid pinnipeds (OW) 60 Hz to 68 kHz.
(underwater) (sea lions and fur
seals).
IN-AIR: .................................
Phocid pinnipeds (PA) (true 42 Hz to 52 kHz.
seals).
Otariid pinnipeds (OA) (sea lions 90 Hz to 40 kHz.
and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS 2018, and/or data from Southall et al. 2007; Southall
et al. 2019. Additionally, animals are able to detect very loud sounds
above and below that ``generalized'' hearing range.
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of the Specified Activity on Marine Mammals and Their
Habitat
The effects of underwater noise from the POA's construction
activities have the potential to result in harassment of marine mammals
in the vicinity of the CTR project area. The proposed rule (89 FR
85686, October 28, 2024) included a discussion of the effects of
anthropogenic noise on marine mammals and the potential effects of
underwater noise from pile installation and extraction activities on
marine mammals and their habitat. There is no newly available relevant
information that would change our analyses or the results thereof.
Please refer to the proposed rule (89 FR 85686, October 28, 2024) for
the potential effects of the POA's activities on marine mammals and
their habitat.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
that may be authorized through issuance of a LOA, which will inform
NMFS' consideration of ``small numbers,'' the negligible impact
determinations, and impacts on subsistence uses.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (i.e., 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 (i.e., Level B harassment).
Authorized takes will primarily be by Level B harassment, as use of
the acoustic sources (i.e., vibratory and impact pile driving) has the
potential to result in disruption of behavioral patterns for individual
marine mammals. There is also some potential for auditory injury (AUD
INJ) constituting Level A harassment to result, primarily for very high
frequency (VHF) cetaceans and phocids because predicted AUD INJ zones
are larger than for high-frequency cetaceans and otariids. AUD INJ is
unlikely to occur for mysticetes, high-frequency cetaceans, and
otariids due to measures described in the Mitigation section. The
required mitigation and monitoring measures are expected to minimize
the severity of the taking to the extent practicable. As described
previously, no serious injury or mortality is anticipated or authorized
for this activity. Below, we describe how the authorized take numbers
were estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the authorized take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
[[Page 31769]]
received level of underwater sound above which exposed marine mammals
would be reasonably likely to be behaviorally harassed (equated to
Level B harassment) or to incur AUD INJ of some degree (equated to
Level A harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (e.g., hearing,
motivation, experience, demography, life stage, depth) and can be
difficult to predict (e.g., Southall et al., 2007, 2021; Ellison et
al., 2012). Based on the best scientific information available and the
practical need to use a threshold based on a metric that is both
predictable and measurable for most activities, NMFS typically uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS generally predicts that marine
mammals are likely to be behaviorally harassed in a manner considered
to be Level B harassment when exposed to underwater anthropogenic noise
above root-mean-squared pressure received levels (RMS SPL) of 120 dB re
1 [mu]Pa for continuous (e.g., vibratory pile driving, drilling) and
above RMS SPL 160 dB re 1 [mu]Pa for non-explosive impulsive (e.g.,
seismic airguns) or intermittent (e.g., scientific sonar) sources.
Generally speaking, Level B harassment estimates based on these
behavioral harassment thresholds are expected to include any likely
takes by TTS as, in most cases, the likelihood of TTS occurs at
distances from the source less than those at which behavioral
harassment is likely. TTS of a sufficient degree can manifest as
behavioral harassment, as reduced hearing sensitivity and the potential
reduced opportunities to detect important signals (e.g., conspecific
communication, predators, prey) may result in changes in behavior
patterns that would not otherwise occur.
The POA's planned activity includes the use of continuous
(vibratory pile driving) and intermittent (impact pile driving) noise
sources, and therefore, the RMS SPL thresholds of 120 and 160 dB re 1
[mu]Pa are applicable.
Level A Harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0; NMFS, 2024) identifies dual criteria to assess AUD INJ (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 (i.e., impulsive or non-impulsive). These thresholds are
provided in the tables below. The references, analysis, and methodology
used in the development of the thresholds are described in NMFS' 2024
Updated Technical Guidance, which may be accessed at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
The POA's planned activity includes the use of impulsive (impact
pile driving) and non-impulsive (vibratory driving) sources.
Table 3--NMFS' 2024 Thresholds Identifying the Onset of Auditory Injury (AUD INJ)
----------------------------------------------------------------------------------------------------------------
AUD INJ acoustic thresholds * (received level)
Hearing group -------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
UNDERWATER:
Low-Frequency (LF) Cetaceans...... Cell 1: L0-pk,flat: 222 Cell 2: LE,LF,24h: 197 dB.
dB; LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans..... Cell 3: L0-pk,flat: 230 Cell 4: LE,HF,24h: 201 dB.
dB; LE,LF,24h: 193 dB.
Very High-Frequency (VHF) Cell 5: L0-pk,flat: 202 Cell 6: LE,VHF,24h: 181 dB.
Cetaceans. dB; LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater) Cell 7: L0-pk.flat: 223 Cell 8: LE,PW,24h: 195 dB.
dB; LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) Cell 9: L0-pk,flat: 230 Cell 10: LE,OW,24h: 199 dB.
(Underwater). dB; LE,OW,24h: 185 dB.
IN-AIR:
Phocid Pinnipeds (PA) (In-Air).... Cell 11: L0-pk.flat: 162 Cell 12: LE,PA,24h: 154 dB.
dB; LE,PA,24h: 140 dB.
Otariid Pinnipeds (OA) (In-Air)... Cell 13: L0-pk,flat: 177 Cell 14: LE,OA,24h: 177 dB.
dB; LE,OA,24h: 163 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI, 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for NMFS' 2018 Technical Guidance. Hence, the
subscript ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted
within the generalized hearing range. The subscript associated with cumulative sound exposure level thresholds
indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW
pinnipeds) and that the recommended accumulation period is 24 hours. The cumulative sound exposure level
thresholds could be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle).
When possible, it is valuable for action proponents to indicate the conditions under which these acoustic
thresholds will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the CTR project area is the existing background
noise plus additional construction noise from the CTR project. Marine
mammals are expected to be affected via sound generated by the primary
components of the CTR project (i.e., impact pile removal and vibratory
pile installation and removal). Calculation of the area ensonified by
the pile driving activities is dependent on the background sound levels
at the CTR project site, the source levels of the activities, and the
estimated transmission loss coefficients for the activities at the
site. These factors are addressed in order, below.
Background Sound Levels at the Port of Alaska--As discussed in the
Specified Geographic Region section of the proposed rule (89 FR 85686,
October 28, 2024), the POA is an industrial facility in a location with
high levels of commercial vessel traffic, port operations (including
dredging), and extreme tidal flow. Previous measurements of background
noise at the POA have recorded a background SPL of 122.2 dB RMS (Austin
et al.,
[[Page 31770]]
2016). NMFS concurs that this SPL reasonably represents background
noise near the CTR project area, and therefore, we have used 122.2 dB
RMS as the threshold for Level B harassment (instead of 120 dB RMS).
Sound Source Levels of CTR Activities. The intensity of pile
driving sounds is greatly influenced by factors such as the type of
piles (e.g., material and diameter), hammer type, and the physical
environment (e.g., sediment type) in which the activity takes place. In
order to calculate the distances to the Level A harassment and the
Level B harassment sound thresholds for the methods and piles being
used in this project, we used acoustic monitoring data from sound
source verification studies (both at the POA and elsewhere) to develop
proxy source levels for the various pile types, sizes and methods
(tables 9 and 10).
The POA collected sound measurements during pile installation and
removal for 3 seasons (Austin et al. 2016; Illingworth & Rodkin (I&R)
2021a, 2021b); a summary of these data and findings can be found in
appendix A of the POA's application.
Vibratory Driving--NMFS concurs that the source levels in the POA's
LOA application for vibratory installation and removal of all pile
types are appropriate to use for calculating harassment isopleths for
the POA's proposed CTR activities (tables 4 and 5). The sound levels
for vibratory removal are based on an analysis done for the POA's NES1
IHA (89 FR 2832, January 14, 2024) and are partially based on sound
source verification data measured at the POA during the PCT project
(Illingworth & Rodkin, 2021a). Interestingly, the analyzed RMS SPL for
the unattenuated vibratory removal of 24-in (61-cm) piles was much
louder than the unattenuated vibratory removal of 36-in piles (91-cm),
and even louder than the unattenuated vibratory installation of 24-in
piles. Illingworth & Rodkin (2023) suggest that at least for data
recorded at the POA, the higher 24-in (61-cm) removal levels are likely
due to the piles being removed at rates of 1,600 to 1,700 revolutions
per minute (rpm), while 36-in (91-cm) piles, which are significantly
heavier than 24-in (61-cm) piles), were removed at a rate of 1,900 rpm.
The slower rates combined with the lighter piles would cause the hammer
to easily ``jerk'' or excite the 24-in (61-cm) piles as they were
extracted, resulting in a louder rattling sound and louder sound
levels. This did not occur for the 36-in (91-cm) piles, which were
considerably heavier due to increased diameter, longer length, and
greater thickness.
The TPP found that for vibratory installation of 48-in piles, an
air bubble curtain provided about a 9-dB reduction at 10 m. An 8-dB
reduction at close-in positions was estimated for vibratory pile
driving that occurred during the PCT project in 2021 (I&R 2021b). The
PCT 2020 measurements indicated 2 to 8 dB reduction for the 48-in piles
at 10 m, but no apparent broadband reduction was found in the far-field
at about 2,800 m (I&R 2021a). Far-field sound levels were characterized
by very low frequency sound at or below 100 Hz, causing broadband
measurements to remain above the ambient RMS level at approximately
2.8km from the source. However, levels at frequencies above 100 Hz were
effectively reduced by the bubble curtain system. Because CIBW are most
sensitive to frequencies over 100 Hz, NMFS considers the use of bubble
curtains during vibratory driving to be a useful mitigation measure for
CIBW.
Based on the aforementioned measurements conducted at POA, for
vibratory driving during the CTR project, it is assumed that a well-
designed and robust bubble curtain system will achieve a mean reduction
of 7 dB at the source for 72-in piles, which are the only pile type for
which site-specific measurements are unavailable. Bubble curtains will
also reduce sound levels at frequencies over 100 Hz at longer ranges.
The POA will use a bubble curtain when water depth is greater than 3 m
during vibratory installation of all permanent (72-in) piles during all
months of construction. The POA may, at its discretion, employ bubble
curtains during vibratory driving of temporary piles to reduce the size
of the required shutdown zones.
Impact Driving--NMFS concurs that the source levels proposed by the
POA for impact installation of all pile types are appropriate to use
for calculating harassment isopleths for the POA's planned CTR
activities (tables 4 and 5). Impact driving of temporary piles (24-in
and 36-in piles) is not currently planned; however, in the unlikely
event that vibratory driving is insufficient to stabilize a temporary
pile, impact driving may be necessary. Sound source verification
studies at the POA during the PCT project did not measure unattenuated
impact driving of 24-in or 36-in piles; therefore, proxy sound levels
from Navy (2015) are used.
The TPP measured reductions of 9 to 12 dB for a 48-in pile
installed with an impact hammer using a confined air bubble curtain.
The PCT 2020 measurements (I&R 2021a) found reductions of about 10 dB
when comparing the attenuated conditions that occurred with that
project to unattenuated conditions for the TPP. The TPP did not report
the reduction in sound levels in the acoustic far field; however, the
computed distances to 125 dB RMS isopleths were essentially reduced by
half with the bubble curtain (from 1,291 to 698 m).
It is currently unclear whether the POA's planned bubble curtain
system for the CTR project will be confined or unconfined; confined
systems are typically more effective, especially in sites like Knik
Arm, with high current velocity. Therefore, for impact pile
installation for the CTR project, it is assumed that a well-designed
and robust bubble curtain system will achieve a mean reduction of 7 dB
from the source. The POA plans to use a bubble curtain system on all
permanent piles in all months, which will be installed with both
vibratory and impact hammers. The bubble curtain by necessity will be
installed around each permanent pile as it is moved into position, and
therefore, the bubble curtain will be available as a mitigation measure
to reduce sound levels throughout each driving event for permanent 72-
in piles when water depth is greater than 3 m. To account for piles
driven in water less than 3 m deep, NMFS has estimated approximately
0.5 unattenuated 72-in piles will be driven (approximately 43 minutes
of impact driving and 5 minutes of vibratory driving) each month.
Concurrent Activities--The POA plans to concurrently operate up to
2 hammers to install or extract piles at different parts of the CTR
project site, in order to reduce the need for pile driving during
months of high CIBW presence. When 2 noise sources have overlapping
sound fields, the sources are considered additive and combined using
the rules of dB addition. For addition of 2 simultaneous sources, the
difference between the 2 sound source levels is calculated, and if that
difference is between 0 and 1 dB, 3 dB are added to the higher sound
source levels; if the difference is between 2 and 3 dB, 2 dB are added
to the highest sound source levels; if the difference is between 4 and
9 dB, 1 dB is added to the highest sound source levels; and with
differences of 10 or more dB, there is no addition. For two
simultaneous sources of different type (i.e., impact and vibratory
driving), there is no sound source addition. Possible concurrent
scenarios and the predicted source values and transmission loss
coefficients for these combinations are shown in table 6.
Transmission Loss--For all piles driven with an active bubble
curtain (i.e., ``attenuated'' impact and vibratory
[[Page 31771]]
driving), and for unattenuated impact installation, the POA proposed to
use 15 as the TL coefficient, meaning they assume practical spreading
loss (i.e., the POA assumes TL = 15*Log<INF>10</INF>(range)); NMFS
concurs with this value and has assumed practical spreading loss for
all (attenuated impact and vibratory) driving and unattenuated impact
driving.
The TL coefficient that the POA proposed for unattenuated vibratory
installation and removal of piles is 16.5 (i.e., TL =
16.5*Log<INF>10</INF>(range)). This value is an average of measurements
obtained from 2, 48-in (122-cm) piles installed via an unattenuated
vibratory hammer in 2016 (Austin et al., 2016). To assess the
appropriateness of this TL coefficient to be used for the CTR project,
NMFS examined and analyzed additional TL measurements recorded at the
POA. This includes a TL coefficient of 22 (deep hydrophone measurement)
from the 2004 unattenuated vibratory installation of one 36-in (91-cm)
pile at Port MacKenzie, across Knik Arm from the POA (Blackwell, 2005),
as well as TL coefficients ranging from 10.3 to 18.2 from the
unattenuated vibratory removal of 24-in (61-cm) and 36-in (91-cm) piles
and the unattenuated vibratory installation of one 48-in (122-cm) pile
at the POA in 2021 (I&R 2021, 2023). To account for statistical
interdependence due to temporal correlations and equipment issues
across projects, values were averaged first within each individual
project, and then across projects. The mean and median value of the
measured TL coefficients for unattenuated vibratory piles in Knik Arm
by project are equal to 18.9 and 16.5, respectively. NMFS therefore
used the project median TL coefficient of 16.5 during unattenuated
vibratory installation and removal of all piles during the CTR project.
This value is representative of all unattenuated vibratory measurements
in the Knik Arm, i.e., including data from POA and Port MacKenzie.
Further, 16.5 is the mean of the 2016 measurements, which were made
closer to the CTR project area than other measurements and were
composed of measurements from multiple directions (both north and
south/southwest).
In certain scenarios, the POA may perform concurrent vibratory
driving of 2 piles. The POA proposed, and NMFS concurs, that in the
event that both piles are unattenuated, the TL coefficient will be
16.5; if both piles are attenuated, the TL coefficient will be 15. In
the event that 1 pile is attenuated and 1 is unattenuated, the POA
proposed a TL coefficient of 15.75 to be used in the acoustic modeling.
NMFS evaluated the contributions of one attenuated and one unattenuated
vibratory-driven pile to the sound field (assuming a 7-dB reduction in
source level due to the bubble curtain for the attenuated source) and
determined that the unattenuated source would likely dominate the
received sound field. Therefore, the POA's proposed TL coefficient is
conservative, and NMFS concurs with this value.
Table 4--Summary of Unattenuated In-Water Pile Driving Proxy Levels
[at 10 m]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory hammer
---------------------------------------------------------------------------------------------------------------------------------------------------------
Method and pile type dB RMS TL coefficient Data source for source levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel installation........................ 161.................................................. 16.5 U.S. Navy 2015.
24-in steel removal............................. 169.................................................. NMFS average 2023; see 89 FR
2832.
36-in steel installation........................ 166.................................................. U.S. Navy 2015.
36-in steel removal............................. 159.................................................. NMFS average 2023; see 89 FR
2832.
72-in steel..................................... 171.................................................. I&R 2003, unpublished data for
Castrol Oil berthing dolphin
in Richmond, CA.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact hammer
-----------------------------------------------------------------------------------------------------------------
Data source for source
dB RMS dB SEL dB peak TL coefficient levels
----------------------------------------------------------------------------------------------------------------
24-in steel............................ 193 181 210 15.0 U.S. Navy 2015.
36-in steel............................ 193 184 211 U.S. Navy 2015.
72-in steel............................ 203 191 217 I&R model. Estimate
based on
interpolation of data
for piles 24 to 144
in diameter.
----------------------------------------------------------------------------------------------------------------
Table 5--Summary of Attenuated In-Water Pile Driving Proxy Levels
[at 10 m]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory hammer
---------------------------------------------------------------------------------------------------------------------------------------------------------
Method and pile type dB RMS TL coefficient Reference for proxy levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel installation........................ 158.5................................................ 15.0 I&R 2021a (measured).
24-in steel removal............................. 157.................................................. I&R 2021a (measured).
36-in steel installation........................ 160.5................................................ I&R 2021a, 2021b (measured).
36-in steel removal............................. 154.................................................. I&R 2021a (measured).
72-in steel..................................... 164.................................................. Assumed 7-dB reduction
supported by I&R 2021a.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact hammer
-----------------------------------------------------------------------------------------------------------------
Reference for proxy
dB RMS dB SEL dB peak TL coefficient levels
----------------------------------------------------------------------------------------------------------------
24-in steel............................ 186 174 203 15.0 Assumed 7-dB reduction
supported by I&R
2021a.
[[Page 31772]]
36-in steel............................ 186 177 204 Assumed 7-dB reduction
supported by I&R
2021a.
72-in steel............................ 196 184 210 Assumed 7-dB reduction
supported by Caltrans
Compendium (2020).
----------------------------------------------------------------------------------------------------------------
Table 6--Source Values for Potential Concurrent Driving Scenarios \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Proxy source value # Piles
Activity Method Pile type/size \2\ Attenuated or unattenuated --------------------------------- TL per day
dB RMS dB SEL dB peak coefficient \3\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Concurrent Driving................ Vibratory/Vibratory........... 36-in and 36-in............ Attenuated/Attenuated................. 163.5 ......... ......... 15 8
(2 sources).......................
Attenuated/Unattenuated............... 169 ......... ......... 15.75 8
Unattenuated/Unattenuated............. 171 ......... ......... 16.5 8
Vibratory/Impact \1\.......... 36in and 72in.............. Attenuated/Attenuated................. 166 ......... ......... 15 7
Unattenuated/Attenuated............... 169 ......... ......... 15.75 7
36in and 72in.............. Attenuated/Attenuated................. 160.5/196 -/184 -/210 15/15 8
Unattenuated/Attenuated............... 166/196 -/184 -/210 16.5/15 7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Concurrent vibratory and impact driving source values and TL coefficients are the same as for the piles driven individually (shown in tables 4 and 5), with no adjustments for concurrent
driving. The Level A harassment isopleths would be determined by the calculated impact pile driving isopleths, and Level B harassment isopleth would be generated by vibratory pile driving.
\2\ POA may elect to use either 36-in or 24-in temporary piles; as 36-in piles are more likely and estimated to have larger ensonified areas, we have used these piles in our analyses of
concurrent activities.
\3\ Piles per day were calculated as the maximum daily number of each type of pile (24-in and 36-in = 4 piles per hammer per day; 72-in piles = 3 piles per day) with complete overlap for 45
minutes of driving with the largest possible combined source value, a scenario that would over-estimate duration of noise production given the estimated time required to drive 72-in piles
with a vibratory hammer (10 minutes).
Estimated Harassment Isopleths--All estimated Level B harassment
isopleths are reported in table 10. At POA, Level B harassment
isopleths from the CTR project will be limited in some cases to less
than the estimated value by the coastline along Knik Arm along and
across from the CTR project site. The maximum predicted isopleth
distance for a single pile is 9,069 m during vibratory installation of
unattenuated 72-in (182-cm) steel pipe piles. For concurrent driving
the maximum isopleth distance is 9,363 m during vibratory driving of
two unattenuated 24- or 36-in piles or during vibratory driving of one
attenuated (24-, 36-, or 72-in) and one unattenuated (24- or 36-in)
pile (tables 15 and 16).
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the Technical Guidance that can be used
to relatively simply predict an isopleth distance for use in
conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources, such as pile driving, the optional User Spreadsheet
tool predicts the distance at which, if a marine mammal remained at
that distance for the duration of the activity, it would be expected to
incur AUD INJ. Inputs used in the optional User Spreadsheet tool and
the resulting estimated isopleths are reported in tables 7 through 10,
below.
Table 7--NMFS User Spreadsheet Inputs for 72-in Permanent Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving Vibratory pile driving
--------------------------------------------------------------------------------------------------------------------
Attenuated Unattenuated \1\ Attenuated Unattenuated \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............... E.1) Impact pile driving
A.1) Non-Impul, Stat, Cont.
--------------------------------------------------------------------------------------------------------------------
Source Level....................... 184 dB SEL.................. 191 dB SEL................. 164 dB RMS................. 171 dB RMS
Transmission Loss Coefficient...... 15.......................... 15......................... 15......................... 16.5
--------------------------------------------------------------------------------------------------------------------
Weighting Factor Adjustment (kHz).. 2
2.5
Time to install single pile --
(minutes).
10
Number of strikes per pile......... 5,743
--
--------------------------------------------------------------------------------------------------------------------
Piles per day...................... 1-3......................... 1.......................... 3
--------------------------------------------------------------------------------------------------------------------
Distance of sound pressure level 10
measurement (m).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ To account for piles driven in water less than 3 m deep, NMFS has estimated approximately 0.5 unattenuated 72-in piles will be driven (approximately
43 minutes of impact driving and 5 minutes of vibratory driving) each month.
[[Page 31773]]
Table 8--NMFS User Spreadsheet Inputs for Temporary (24- or 36-in) Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile driving
---------------------------------------------------------------------------------------------------------
24-in (61-cm) steel pipe 36-in (91-cm) steel pipe
---------------------------------------------------------------------------------------------------------
Removal Removal
Installation ---------------------------------------------------- Installation -------------------------
Atten Unatten Atten Unatten Atten Unatten
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used.......................... A.1) Non-Impul, Stat, Cont.
---------------------------------------------------------------------------------------------------------
Source Level (dB RMS)......................... 158.5 161 157 169 160.5 166 154 159
Transmission Loss Coefficient................. 15 16.5 15 16.5 15 16.5 15 16.5
---------------------------------------------------------------------------------------------------------
Weighting Factor Adjustment (kHz)............. 2.5
---------------------------------------------------------------------------------------------------------
Time to install or remove single pile
(minutes).................................... 30
45
30
45
---------------------------------------------------------------------------------------------------------
Number of strikes per pile.................... --
Piles per day................................. 4
Distance of sound pressure level measurement
(m).......................................... 10
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in (61-cm) steel pipe
36-in (91-cm) steel pipe
--------------------------------------------------------------------------------------------------------------------------------------------------------
Attenuated
Unattenuated
Attenuated
Unattenuated
---------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used.......................... E.1) Impact pile driving
---------------------------------------------------------------------------------------------------------
Source Level.................................. 174 dB SEL
181 dB SEL
177 dB SEL
184 dB SEL
---------------------------------------------------------------------------------------------------------
Transmission Loss Coefficient................. 15
Weighting Factor Adjustment (kHz)............. 2
Time to install or remove single pile
(minutes).................................... --
Number of strikes per pile.................... 1,000
Piles per day................................. 1
Distance of sound pressure level measurement
(m).......................................... 10
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 9--NMFS User Spreadsheet Inputs for Concurrent Vibratory Driving
----------------------------------------------------------------------------------------------------------------
24- or 36-in AND 24-in or 36-in 24- or 36-in AND 72-in
---------------------------------------------------------------------------------
Attenuated/ Attenuated/ Unattenuated/ Attenuated/ Unattenuated/
attenuated unattenuated unattenuated attenuated attenuated
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used.......... Non-Impul, Stat, Cont.
---------------------------------------------------------------------------------
Source Level (dB RMS)......... 163.5 170 172 166 170
Transmission Loss Coefficient. 15 15.75 16.5 15 15.75
---------------------------------------------------------------------------------
Weighting Factor Adjustment
(kHz)........................ 2.5
Time to install or remove a
single pile (minutes)........ 45
Number of strikes per pile.... --
---------------------------------------------------------------------------------
Piles per day................. 8
7
---------------------------------------------------------------------------------
Distance of sound pressure
level measurement (m)........ 10
----------------------------------------------------------------------------------------------------------------
Table 10--Calculated Distance of Level A (Based on NMFS' 2024 Updated Technical Guidance) and Level B Harassment Isopleths by Pile Type and Pile Driving
Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment distance (m) Level B
------------------------------------------------------- harassment
Activity Pile type/size Attenuated or distance (m)
unattenuated LF HF VHF PW OW all hearing
groups \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact.......................... 24-in (61-cm).............. Unattenuated...... 732 94 1,133 651 243 1,585
Attenuated........ 250 32 387 222 83 541
36-in (91-cm).............. Unattenuated...... 1,160 148 1,796 1,031 385 1,585
Attenuated........ 397 51 613 352 132 541
72-in (182-cm)............. Unattenuated...... 10,896 1,390 16,861 9,679 3,608 7,356
Attenuated (1 pile 3,720 474.7 5,757 3,305 1,232 2,512
per day).
Attenuated (2 5,906 753.5 9,139 5,246 1,956
piles per day).
Attenuated (3 7,739 987.4 11,976 6,875 2,563
piles per day).
Vibratory Installation.......... 24-in (61-cm).............. Unattenuated...... 14.1 5.9 11.8 17.8 6.6 2,247
Attenuated........ 10 3.8 8.1 12.8 4.3 2,630
36-in (91-cm).............. Unattenuated...... 28.4 11.9 23.6 35.7 13.3 4,514
Attenuated........ 13.6 5.2 11.1 17.5 5.9 3,575
[[Page 31774]]
72-in (182-cm)............. Unattenuated...... 24.6 10.3 20.5 31 11.5 9,069
Attenuated........ 9.2 3.5 7.5 11.9 4 6,119
Vibratory Removal............... 24-in (61-cm).............. Unattenuated...... 55.2 23.1 45.9 69.5 25.8 6,861
Attenuated........ 10.4 4 8.5 13.4 4.5 2,089
36-in (91-cm).............. Unattenuated...... 13.7 5.7 11.4 17.2 6.4 1,699
Attenuated........ 6.6 2.5 5.4 8.4 2.8 1,318
Concurrent Vibratory/Vibratory.. 36-in AND 36-in............ Attenuated/ 44.7 17.2 36.5 57.5 19.4 5,667
Attenuated.
Attenuated/ 107.6 43.3 88.8 136.9 48.5 9,363
Unattenuated.
Unattenuated/ 127.7 53.5 106.3 160.7 59.7 9,069
Unattenuated.
36-in AND 72-in............ Attenuated/ 60 23.1 49 77.3 26 8,318
Attenuated.
Unattenuated/ 98.9 39.8 81.6 125.8 44.6 9,363
Attenuated.
Concurrent Vibratory/Impact..... 36-in AND 72-in............ Attenuated/ 3,720 474.7 5,757 3,305 1,232 3,575
Attenuated (1
pile per day).
Attenuated/ 5,906 753.5 9,139 5,246 1,956
Attenuated (2
piles per day).
Attenuated/ 7,739 987.4 11,976 6,875 2,563
Attenuated (3
piles per day).
Unattenuated/ 3,720 474.7 5,757 3,305 1,232 4,514
Attenuated (1
pile per day).
Unattenuated/ 5,906 753.5 9,139 5,246 1,956
Attenuated (2
piles per day).
Unattenuated/ 7,739 987.4 11,976 6,875 2,563
Attenuated (3
piles per day).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Distances to thresholds are as modeled; however, interaction with shorelines would truncate zones. See figures 6-1 through 6-10 in the POA's
application for further details.
Marine Mammal Occurrence
In this section, we provide information about the occurrence of
marine mammals, including density or other relevant information, which
informed the take calculations. Available information regarding marine
mammal occurrence and abundance in the vicinity of the POA includes
monitoring data from the PCT and SFD projects. These programs produced
a unique and comprehensive data set of marine mammal sightings and for
CIBWs, locations and movements near the POA (61N Environmental, 2021,
2022a, 2022b; Easley-Appleyard and Leonard, 2022). This is the most
current data set available for Knik Arm. During the PCT and SFD
projects, the POA's marine mammal monitoring programs included 11 PSOs
working from four elevated, specially designed monitoring stations
located along a 9-km stretch of coastline surrounding the POA. The
number of days data was collected varied among years and projects, with
128 days during PCT Phase 1 in 2020, 74 days during PCT Phase 2 in
2021, and 13 days during SFD in 2022 (see tables 6-15 in the POA's
application for additional information regarding CIBW monitoring data).
PSOs during these projects used 25-power ``big-eye'' and hand-held
binoculars to detect and identify marine mammals and theodolites to
track movements of CIBW groups over time and collect location data
while they remained in view.
These POA monitoring programs were supplemented in 2021 with a
NMFS-funded visual marine mammal monitoring project that collected data
during non-pile driving days during PCT Phase 2 (Easley-Appleyard and
Leonard, 2022). NMFS replicated the POA monitoring efforts, as
feasible, including use of 2 of the POA's monitoring platforms,
equipment (Big Eye binoculars, theodolite, 7x50 reticle binoculars),
data collection software, monitoring and data collection protocol, and
observers; however, the NMFS-funded program utilized only 4 PSOs and 2
observation stations along with shorter (4- to 8-hour) observation
periods compared to PCT or SFD data collection, which included 11 PSOs,
4 observation stations, and most observation days lasting close to 10
hours. Despite the differences in effort, the NMFS dataset fills in
gaps during the 2021 season and is thus valuable in this analysis.
NMFS' PSO's monitored for 231.6 hours on 47 non-consecutive days in
July, August, September, and October.
Density data are not available for any of the relevant species in
this area; therefore, we have used reasonable yearly, monthly, or
hourly occurrence estimates based on the previous POA monitoring
datasets for all species. Table 11 shows the estimated occurrence rates
for non-CIBW species at the POA; descriptions are provided in the text
below.
Table 11--Estimated Occurrence for Non-CIBW Species at the POA
----------------------------------------------------------------------------------------------------------------
Estimated Estimated annual Estimated 5-year
Species Timeframe occurrence rates occurrence occurrence
----------------------------------------------------------------------------------------------------------------
Gray whale...................... Yearly............ 6/year............ 6 30
Humpback whale.................. 4/year............ 4 20
Killer whale.................... 6/year............ 6 30
Steller sea lion................ 9/year............ 9 45
Harbor porpoise................. Hourly............ 0.15/hour......... 1,314 6,570
Harbor seal..................... 1/hour............ 8,760 43,800
----------------------------------------------------------------------------------------------------------------
[[Page 31775]]
Gray Whale
Sightings of gray whales in the CTR project area are rare. Few, if
any, gray whales are expected to approach the CTR project area.
However, based on three separate sightings of single gray whales near
the POA in 2020 and 2021 (61N Environmental, 2021, 2022a; Easley-
Appleyard and Leonard, 2022), the POA anticipates that up to 6
individuals could occur within estimated harassment zones each year
during CTR project activities.
Humpback Whale
Sightings of humpback whales in the CTR project area are rare, and
few, if any, humpback whales are expected to approach the CTR project
area. However, there have been previous observations of humpback whales
near the POA. Based on the 2 sightings in 2017 of what was likely a
single individual at the Anchorage Public Boat Dock at Ship Creek (ABR,
Inc., 2017) south of the CTR project area, the POA estimated that 6
humpback whales per year may occur in the vicinity of the CTR project.
However, given the maximum number of humpback whales observed within a
single construction season was two (in 2017), NMFS instead anticipates
that only up to 4 humpback whales could be exposed to project-related
underwater noise per year during the CTR project.
Killer Whale
Few, if any, killer whales are expected to approach the CTR project
area. No killer whales were sighted during previous monitoring programs
for POA construction projects, including the 2016 TPP, 2020 PCT, and
2022 SFD projects (Prevel-Ramos et al., 2006; Markowitz and McGuire,
2007; Cornick and Saxon-Kendall, 2008, 2009; Cornick et al., 2010,
2011; ICRC, 2009, 2010, 2011, 2012; Cornick and Pinney, 2011; Cornick
and Seagars, 2016; 61N Environmental, 2021, 2022b), except during PCT
construction in 2021, when 2 killer whales were sighted (61N
Environmental, 2022a). Previous sightings of transient killer whales
have documented pod sizes in upper Cook Inlet between 1 and 6
individuals (Shelden et al., 2003). The POA estimates, and NMFS
concurs, that 1 pod (assumed to be 6 individuals) could occur within
the CTR project area during CTR project activities each year.
Harbor Porpoise
Monitoring data recorded from 2005 through 2022 were used to
evaluate hourly sighting rates for harbor porpoises in the proposed CTR
area (see table 4-3 in the POA's application). During most years of
monitoring, no harbor porpoises were observed. However, there has been
an increase in harbor porpoise sightings in upper Cook Inlet in recent
decades (e.g., 61N Environmental, 2021, 2022a; Shelden et al., 2014).
The highest sighting rate for any recorded year during in-water pile
installation and removal was an average of 0.037 harbor porpoises per
hour during PCT construction in 2021, when observations occurred across
most months. Given the uncertainty around harbor porpoise occurrence at
the POA and potential that occurrence is increasing, the POA calculated
requested takes using a sighting rate of 0.5 harbor porpoises per hour.
For the recent NES1 project (88 FR 76576, November 6, 2023), NMFS
estimated that a more realistic sighting rate would be closer to
approximately 0.07 harbor porpoises per hour (the 2021 rate of 0.037
harbor porpoises per hour doubled). However, the sizes of the
ensonified areas for the NES1 project are much smaller than those
predicted for the CTR project. Based on the larger ensonified areas,
which more closely resemble the observable area from the PCT project,
the cryptic nature of the species, and the potential for increased
occurrence of harbor porpoise in and around upper Cook Inlet, NMFS
estimates that approximately 0.15 harbor porpoises per hour (four times
the maximum observed 2021 rate of 0.037 per hour) may be observed near
the CTR area during the 5 years covered under this rulemaking.
Steller Sea Lion
Steller sea lions are anticipated to occur in low numbers within
the CTR project area as summarized in the Description of Marine Mammals
in the Area of Specified Activities section. Similar to the approach
used above for harbor porpoises, the POA used previously recorded
sighting rates of Steller sea lions near the POA to estimate requested
take for this species. During SFD construction in May and June of 2022,
the hourly sighting rate for Steller sea lions was 0.028. The hourly
sighting rate for Steller sea lions in 2021, the most recent year with
observations across most months, was approximately 0.01. The highest
number of Steller sea lions that have been observed during the 2020-
2022 monitoring efforts at the POA was 9 individuals (8 during PCT
Phase 1 monitoring and 1 during NMFS' 2021 monitoring).
Recent counts of sightings of Steller sea lions around the POA may
include multiple re-sights of single individuals. For instance, in
2016, Steller sea lions were observed on 2 separate days. On May 2,
2016, 1 individual was sighted, while on May 25, 2016, there were 5
Steller sea lion sightings within a 50-minute period, and these
sightings occurred in areas relatively close to one another (Cornick
and Seagars, 2016). Given the proximity in time and space, it is
believed these 5 sightings were of the same individual sea lion. The
POA is concerned that multiple re-sights of a single individual within
a day may overestimate the true number of individuals exposed to sound
levels at or above harassment thresholds over the course of the CTR
project. Therefore, given the uncertainty around Steller sea lion
occurrence at the POA and potential that occurrence is increasing, the
POA estimated that approximately 0.14 Steller sea lions per hour (the
May and June 2022 rate of 0.028 Steller sea lions per hour multiplied
by a factor of 5) may be observed near the proposed CTR project areas
per hour of hammer use. However, the highest number of Steller sea lion
sightings during the 2020-2022 monitoring efforts at the POA was 9 (8
during PCT Phase 1 monitoring and 1 during NMFS' 2021 monitoring).
Given the POA's estimate assumes a higher Steller sea lion sighting
rate (0.14) than has been observed at the POA and results in an
estimate that is more than double the maximum number of Steller sea
lions observed in a year, NMFS believes that the sighting rate proposed
by the POA overestimates potential exposures of this species. Based on
the ensonified areas, which closely resemble the observable area from
the PCT project, the potential for re-sightings of individual animals,
and the uncertainty around increased occurrence of Steller sea lions in
and around upper Cook Inlet, NMFS instead assumes that 9 Steller sea
lions (i.e., the maximum number observed in a single year between 2020
and 2022 during projects with similar sized harassment isopleths) could
occur within the CTR project area each year during the 5 years covered
under this rulemaking.
Harbor Seal
No known harbor seal haulout or pupping sites occur in the vicinity
of the POA. In addition, harbor seals are not known to reside in the
CTR project area, but they are seen regularly near the mouth of Ship
Creek when salmon are running, from July through September. With the
exception of newborn pups, all ages and sexes of harbor seals could
occur in the CTR project area. Harbor seals often appear curious about
onshore activities and may approach closely. The mouth of Ship Creek,
[[Page 31776]]
where harbor seals linger, is about 1,500 m from the southern end of
the CTR project area.
The POA evaluated marine mammal monitoring data to calculate hourly
sighting rates for harbor seals in the CTR project area (see table 4-1
in the POA's application). Of the 524 harbor seal sightings in 2020 and
2021, 93.7 percent of the sightings were of single individuals; only
5.7 percent of sightings were of 2 individual harbor seals, and only
0.6 percent of sightings reported 3 harbor seals. Sighting rates of
harbor seals were highly variable and appeared to have increased during
monitoring between 2005 and 2022. It is unknown whether any potential
increase was due to local population increases or habituation to
ongoing construction activities. The highest individual hourly sighting
rate recorded for the previous year was used to quantify take of harbor
seals for in-water pile installation and removal associated with CTR.
This occurred in 2021 during PCT Phase 2 construction, when harbor
seals were observed from May through September. A total of 220 harbor
seal sightings were observed over 734.9 hours of monitoring, at an
average rate of 0.30 harbor seal sightings per hour. The maximum
monthly sighting rate occurred in September 2020 and was 0.51 harbor
seal sightings per hour. Based on these data, the POA estimated, and
NMFS concurs, that approximately 1 harbor seal (the maximum monthly
sighting rate (0.51) rounded up) may be observed near the CTR project
per hour of hammer use.
Beluga Whale
CIBWs are regular and frequent visitors to Knik Arm, sometimes
passing by the POA multiple times a day, as documented by the previous
PAMP monitoring projects (61N Environmental, 2021, 2022a, 2022b).
Distances from CIBW sightings to the CTR project site from the POA and
NMFS-funded monitoring programs ranged from less than 10 m up to nearly
15 km. The robust marine mammal monitoring programs in place at the POA
from 2020 through 2022 located, identified, and tracked CIBWs at
greater distances from the proposed project site than previous
monitoring programs (i.e., Kendall and Cornick, 2015) and has
contributed to a better understanding of CIBW movements in upper Cook
Inlet (e.g., Easley-Appleyard and Leonard, 2022).
For the NES1 project, NMFS and the POA collaboratively developed a
new sighting rate methodology that incorporates a spatial component for
CIBW observations, which allows for more accurate estimation of
potential take of CIBWs (89 FR 2832, January 14, 2024). We have used
this same methodology in the analysis of estimated CIBW incidental take
during the CTR project. A detailed description of the differences from
the sighting-rate methods used in the PCT and SFD projects can be found
in the proposed rule for the NES1 project (88 FR 76576, November 6,
2023).
During the POA's and NMFS' marine mammal monitoring programs for
the PCT and SFD projects (table 12), PSOs had an increased ability to
detect, identify, and track CIBWs groups at greater distances from the
project work site when compared with previous years because of the
POA's expanded monitoring program as described above. This meant that
observations of CIBWs in the 2020-2022 dataset (table 12) include
sightings of individuals at distances far outside some of the
ensonified areas estimated for the CTR project and at ranges close to
the extent of the larger ensonified areas (table 10). Therefore, it
would not be appropriate to group all CIBW observations from these
datasets into a single sighting rate as was done for the PCT and SFD
projects. Rather, CIBW observations were considered in relation to
their distance to the CTR project site when determining appropriate
sighting rates to use when estimating take for this project. This
helped to ensure that the sighting rates used to estimate take are
representative of CIBW presence in the estimated ensonified areas.
Table 12--Marine Mammal Monitoring Data Used for CIBW Sighting Rate Calculations
----------------------------------------------------------------------------------------------------------------
Number of
Year Monitoring type and data source CIBW group Number of CIBW Number of
fixes groups CIBWs
----------------------------------------------------------------------------------------------------------------
2020........................ PCT: POA Construction Monitoring, 2,653 245 987
61N Environmental, 2021.
2021........................ PCT: NMFS Monitoring, Easley- 694 \1\ 109 575
Appleyard and Leonard, 2022.
2021........................ PCT: POA Construction Monitoring, 1,339 132 517
61N Environmental, 2021, 2022a.
2022........................ SFD: POA Construction Monitoring, 151 9 41
61N Environmental, 2022b.
2024........................ NES1: POA Construction Monitoring, 4,618 433 1,924
61N Environmental, 2025.
----------------------------------------------------------------------------------------------------------------
\1\ This number differs slightly from table 6-8 in the POA's application due to our removal of a few duplicate
data points in the NMFS data set.
To incorporate a spatial component into the sighting rate
methodology, the POA calculated each CIBW group's closest point of
approach (CPOA) relative to the CTR project site. The 2020-2022 and
2024 marine mammal monitoring programs (table 12) enabled the
collection, in many cases, of multiple locations of CIBW groups as they
transited through Knik Arm, which allowed for track lines to be
interpolated for many groups. The 2024 sightings data were received
from the POA on March 3, 2024 and have been analyzed according to the
same methodologies described in the proposed rule (89 FR 85686, October
28, 2024). The POA used these track lines or single recorded locations
in instances where only one sighting location was available to
calculate each group's CPOA. CPOAs were calculated in ArcGIS software
using the Geographic Positioning System (GPS) coordinates provided for
documented sightings of each group (for details on data collection
methods, see 61N Environmental, 2021, 2022a, 2022b; 2025; Easley-
Appleyard and Leonard, 2022) and the CTR location midpoint, centered on
the CTR project site. A CIBW group was defined as a sighting of one or
more CIBWs as determined during data collection. The most distant CPOA
location to CTR was 12,791 m and the closest CPOA location was 6 m.
The cumulative density distribution of CPOA values represents the
percentage of CIBW observations that were within various distances to
the CTR project site (figure 1). This distribution shows how CIBW
observations differed with distances to the CTR site and was used to
infer appropriate distances within which to estimate spatially-derived
CIBW sighting rates (figure 1). The POA implemented a piecewise
regression model that detected breakpoints (i.e., points within the
CPOA data at which statistical properties of the sequence of
observational distances changed) in the cumulative density distribution
of the CPOA locations, which they proposed
[[Page 31777]]
to represent spatially-based sighting rate bins for use in calculating
CIBW sighting rates. The POA used the ``Segmented'' package (Muggeo,
2020) in the R Statistical Software Package (R Core Team, 2022) to
determine statistically significant breakpoints in the linear distances
of the CIBW data using this regression method (see section 6.5.5.3 of
the POA's application for more details regarding this statistical
analysis). This analysis identified breakpoints in the CPOA locations
at 281, 2,213, 3,149, and 6,639 m (figure 1), differ by between 5.7 and
335 m from the breakpoints identified from the 2020 and 2021 data
(i.e., 195.7; 2,337; 3,154.7; and 6,973.9 m) in the proposed rule (89
FR 85686, October 28, 2024).
[GRAPHIC] [TIFF OMITTED] TR15JY25.017
Piecewise regression is a common tool for modeling ecological
thresholds (Lopez et al., 2020; Whitehead et al., 2016; Atwood et al.,
2016). In a similar scenario to the one outlined above, Mayette et al.
(2022) used piecewise regression methods to model the distances between
two individual CIBWs in a group in a nearshore and a far shore
environment. For the POA's analysis, the breakpoints (i.e., 281, 2,213,
3,149, and 6,639 m) detect a change in the frequency of CIBW groups
sighted and the slope of the line between two points indicates the
magnitude of change. A greater positive slope indicates a greater
accumulation of sightings over the linear distance (x-axis) between the
defining breakpoints, whereas a more level slope (i.e., closer to zero)
indicates a lower accumulation of sightings over that linear distance
(x-axis) between those defining breakpoints (figure 1; see table 6-16
in the POA's application for the slope estimates for the empirical
cumulative distribution function).
The breakpoints identified by the piecewise regression analysis are
in agreement with what is known about CIBW behavior in Knik Arm based
on recent monitoring efforts (61N Environmental, 2021, 2022a, 2022b,
2025; Easley-Appleyard and Leonard, 2022). Observation location data
collected during POA monitoring programs indicate that CIBWs were
consistently found in higher numbers in the nearshore areas, along both
shorelines, and were found in lower numbers in the center of the Arm.
Tracklines of CIBW group movements collected from 2020 to 2022 and 2024
show that CIBWs displayed a variety of movement patterns that included
swimming close to shore past the POA on the east side of Knik Arm
(defined by breakpoint 1 at 281 m), with fewer CIBWs swimming in the
center of Knik Arm (breakpoints 1 to 2, at 281 to 2,213 m). CIBWs
commonly swam past the POA close to shore on the west side of Knik Arm,
with no CIBWs able to swim farther from the POA in that area than the
far shore (breakpoints 2 to 3, at 2,213 to 3,149 m). Behaviors and
locations beyond breakpoint 4 (6,639 m) include swimming past the mouth
of Knik Arm between the Susitna River area and Turnagain Arm; milling
at the mouth of Knik Arm but not entering the Arm; and milling to the
northwest of the POA without exiting Knik Arm. The shallowness of slope
5, at distances greater than 6,639 m, could be due to detection falloff
from a proximity (distance) bias, which would occur when PSOs are less
likely to detect CIBW groups that are farther away than groups that are
closer.
The POA, in collaboration with NMFS, used the distances detected by
the breakpoint analysis to define 5 sighting rate distance bins for
CIBWs in the NES1 project area. Each breakpoint (281, 2,213, 3,149, and
6,639 m, and the complete data set of observations (>6,639 m)) was
rounded up to the nearest meter and considered the outermost limit of
each sighting rate bin, resulting in 5 identified bins (table 19).
[[Page 31778]]
All CIBW observations less than each bin's breakpoint distance were
used to calculate that bin's respective monthly sighting rates (e.g.,
all sightings from 0 to 281 m are included in the sighting rates
calculated for bin number 1, all sightings from 0 to 2,213 m are
included in the sighting rates calculated for bin number 2, and so on).
CTR construction is anticipated to take place in the months of April
through November over the 5-year timeframe of this rule; therefore,
monthly sighting rates were only derived for these months (table 13).
Table 13--CIBW Monthly Sighting Rates for Different Spatially-Based Bin Sizes
--------------------------------------------------------------------------------------------------------------------------------------------------------
CIBW/hour \1\
Bin No. Distance --------------------------------------------------------------------------------
(m) April May June July August September October November
--------------------------------------------------------------------------------------------------------------------------------------------------------
1........................................................... 281 0.05 0.04 0.14 0.03 0.97 0.39 0.53 0.02
2........................................................... 2213 0.32 0.16 0.36 0.11 1.97 1.35 1.18 0.65
3........................................................... 3149 0.36 0.22 0.47 0.13 2.62 2.01 1.97 0.72
4........................................................... 6639 0.64 0.31 0.57 0.16 2.88 2.30 2.35 0.73
5........................................................... >6639 0.71 0.39 0.58 0.16 2.94 2.35 2.48 0.73
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Observation hours have been totaled from the PCT 2020 and 2021 programs, the NMFS 2021 data collection effort, and the SFD 2022 program (61N
Environmental 2021, 2022a, 2022b, 2025; Easley-Appleyard and Leonard, 2022).
Take Estimation
In this section, we describe how the information provided above was
synthesized to produce a quantitative estimate of the take that is
reasonably likely to occur and may be authorized.
To quantitatively assess exposure of marine mammals to noise from
pile driving activities, we used the occurrence estimate (number/unit
of time; tables 11 and 13) and the estimated work hours per year (table
14) to determine the number of animals potentially exposed to an
activity. Because the size of the Level A harassment zones may exceed
the shutdown zones (see the Mitigation section) and the limits of PSO
visibility during impact driving activities, the number of takes by
Level A harassment was estimated based on the proportion of work hours
allocated to impact pile driving (table 14) for all species except
killer whales, which have smaller predicted Level A harassment zones,
and CIBWs, which have larger required shutdown zones, described in
further detail below.
For killer whales, while unlikely, it is possible that a group
could approach the POA from the northern portion of Knik Arm and
immediately enter into a Level A harassment zone before PSOs are able
to shut down pile driving activities. The POA estimates, and NMFS
concurs, that 1 pod (assumed to be 6 individuals) could be taken by
Level A harassment over the 5 years of the CTR project.
Table 14--Estimated Predicted Number of Hours of Impact and Vibratory Hammer Use for Each Construction Year
----------------------------------------------------------------------------------------------------------------
Proportion of
Year Impact Vibratory Total duration impact hammer
duration (hrs) duration (hrs) (hrs) use
----------------------------------------------------------------------------------------------------------------
1.............................................. 98.9 55.0 153.9 0.6
2.............................................. 87.4 47.9 135.4 0.7
3.............................................. 38.7 96.5 135.2 0.3
4.............................................. 87.4 50.4 137.9 0.6
5.............................................. 81.7 55.5 137.2 0.6
----------------------------------------------------------------------------------------------------------------
The equation used to calculate estimated take by Level A harassment
for species with yearly occurrence estimates is:
Level A harassment estimate = occurrence x proportion of impact
hammer use where occurrence per year is taken from table 11, and
proportion of impact hammer use per year from table 14. For species
with hourly occurrence estimates, the equation is:
Level A harassment estimate = (hourly occurrence x total duration
in hours) x proportion of impact hammer use.
Estimates of take by Level A and Level B harassment for all species
are based on the best available data. NMFS will authorize total takes
for each species by Level A and Level B harassment over the 5-year
period of the proposed ITR as calculated and shown in the relevant
tables, with annual take by Level A and Level B harassment for each
species not to exceed the maximum annual values shown in tables 15, 16,
and 19.
Table 15--Authorized Take by Level A Harassment in Each of the 5 Years and in Total for Non-CIBW Marine Mammal
Species in the CTR Project Area \1\
----------------------------------------------------------------------------------------------------------------
Authorized Level A harassment by year
Species -----------------------------------------------------------------------------
1 2 3 4 5 Total
----------------------------------------------------------------------------------------------------------------
Gray whale........................ 4 4 2 4 4 18
Humpback whale.................... 3 3 1 3 2 12
-----------------------------------------------------------------------------
Killer whale...................... 6 6
-----------------------------------------------------------------------------
Harbor porpoise................... 15 13 6 13 12 59
[[Page 31779]]
Steller sea lion.................. 6 6 3 6 5 26
Harbor seal....................... 98 88 39 87 82 394
----------------------------------------------------------------------------------------------------------------
\1\ Annual take may not be distributed exactly as shown; NMFS authorizes total take over the 5 year construction
period, with annual take by Level A harassment for each species not to exceed the maximum annual value shown
in years 1-5.
Estimates of take by Level B harassment for non-CIBW species were
calculated as the difference between the estimated Level A harassment
exposures and total estimated yearly occurrence (either the estimated
yearly occurrence from table 15 or calculated as the hourly occurrence
from table 11 multiplied by the total yearly duration in table 14) for
each stock.
Table 16--Authorized Take by Level B Harassment in Each of the 5 Years and in Total for Non-CIBW Marine Mammal
Species in the CTR Project Area \1\
----------------------------------------------------------------------------------------------------------------
Authorized Level B harassment by year
Stock -----------------------------------------------------------------------------
1 2 3 4 5 Total
----------------------------------------------------------------------------------------------------------------
Gray whale........................ 2 2 4 2 2 12
Humpback whale.................... 1 1 3 1 2 8
Killer whale...................... 6 6 6 6 6 30
Harbor porpoise................... 8 7 14 8 8 45
Steller sea lion.................. 3 3 6 3 4 20
Harbor seal....................... 55 47 96 51 55 304
----------------------------------------------------------------------------------------------------------------
\1\ Annual take may not be distributed exactly as shown; NMFS authorizes total take over the 5 year construction
period, with annual take by Level A and Level B harassment not to exceed the sum of the maximum annual values
shown in years 1-5 in tables 15 and 16.
Beluga Whale
Potential exposures above harassment thresholds of CIBWs, which we
equate with takes, were calculated by multiplying the total number of
vibratory installation or removal hours per month for each sized/shaped
pile based on the anticipated construction schedule (see table 2 in the
proposed rule) with the corresponding sighting rate month and sighting
rate distance bin (table 17). For example, the Level B harassment
isopleth distance for the vibratory installation of 36-in (91-cm) piles
is 4,514 m, which falls within bin number 4 (table 17). Therefore, take
for this activity was calculated by multiplying the total number of
hours estimated each month to install 36-in piles via a vibratory
hammer by the monthly CIBW sighting rates calculated for bin number 4
(table 17). The resulting estimated CIBW exposures were totaled for all
activities in each month (table 18).
In their calculation of CIBW take, the POA assumed that only 36-in
template piles will be installed (rather than 24-in) and removed during
the CTR project. If 24-in piles are used for temporary stability
template piles, it would be assumed that the potential impacts of this
alternate construction scenario and method on marine mammals are
fungible (i.e., that potential impacts of installation and removal of
24-in steel pipe piles would be similar to the potential impacts of
installation and removal of 36-in steel pipe piles). While removal of
24-in piles may be louder than removal of 36-in piles (tables 9 and
10), installation would be significantly quieter. Given the number of
piles to be installed and extracted using vibratory methods, overall
impacts from 36-in piles are expected to be greater than those from 24-
in piles.
Table 17--Allocation of Each Level B Harassment Isopleth to a Sighting Rate Bin and CIBW Monthly Sighting Rates for Different Pile Sizes and Hammer
Types
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B CIBWs/hour
isopleth Sighting rate ---------------------------------------------------------------------------------------
Activity distance bin No. and
(m) distance Apr May Jun Jul Aug \1\ Sep \1\ Oct \1\ Nov
--------------------------------------------------------------------------------------------------------------------------------------------------------
Unattenuated Values (without the use of a bubble curtain)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in Vibratory Removal \1\ \2\..... 1,699 2 (2,213 m) 0.32 0.16 0.36 0.11 1.97 1.35 1.18 0.65
36-in Vibratory Installation \1\ \2\ 4,514 4 (6,639 m) 0.64 0.31 0.57 0.16 2.88 2.30 2.35 0.73
72-in Vibratory Installation \3\.... 9,069 5 (>6,639) 0.71 0.39 0.58 0.16 2.94 2.35 2.48 0.73
[[Page 31780]]
Concurrent 36-in AND 36-in Vibratory 9,069
Installation.......................
Concurrent 36-in AND 36-in OR 72-in 9,363
Vibratory Installation \4\.........
36-in Impact Installation \1\ \2\... 1,585 2 (2,213 m) 0.32 0.16 0.36 0.11 1.97 1.35 1.18 0.65
72-in Impact Installation \3\....... 7,356 5 (>6,639) 0.71 0.39 0.58 0.16 2.94 2.35 2.48 0.73
--------------------------------------------------------------------------------------------------------------------------------------------------------
Attenuated Values (with the use of a bubble curtain)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in Vibratory Removal \2\......... 1,318 2 (2,213) 0.32 0.16 0.36 0.11 1.97 1.35 1.18 0.65
36-in Vibratory Installation \2\.... 3,575 4 (6,639 m) 0.64 0.31 0.57 0.16 2.88 2.30 2.35 0.73
72-in Vibratory Installation \3\.... 6,119
Concurrent 36-in AND 36-in Vibratory 5,667
Installation.......................
Concurrent 36-in AND 72-in Vibratory 8,318 5 (>6,639) 0.71 0.39 0.58 0.16 2.94 2.35 2.48 0.73
Installation.......................
36-in Impact Installation \1\ \2\... 541 2 (2,213) 0.32 0.16 0.36 0.11 1.97 1.35 1.18 0.65
72-in Impact Installation........... 2,512 3 (3,149 m) 0.36 0.22 0.47 0.13 2.62 2.01 1.97 0.72
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Unattenuated vibratory and impact driving of permanent piles during the months of August through October would be limited to the minimum possible
number of piles that must be driven in-water in depths <3 m.
\2\ Unattenuated and attenuated vibratory installation of 36-in temporary piles both result in bin 4; vibratory removal of this pile type results in bin
2 in both attenuated and unattenuated conditions. Unattenuated and attenuated impact pile driving of 36-in piles results in bin 2 in both conditions.
\3\ Unattenuated vibratory and impact installation of permanent (72-in) piles will be minimized to the extent possible by driving as many piles as
possible in the dry for all months of the construction seasons. To account for piles driven in water less than 3 m deep, NMFS has estimated
approximately 0.5 unattenuated 72-in piles will be driven (approximately 43 minutes of impact driving and 5 minutes of vibratory driving) each month.
Impact driving (attenuated and unattenuated) results in Bin 2; vibratory driving (attenuated and unattenuated) results in Bin 5.
\4\ Both concurrent driving of 2 temporary piles (1 attenuated, 1 unattenuated) and 1 temporary (unattenuated) and 1 permanent (attenuated) piles result
in a Level B harassment isopleth of 9,363 m.
For the PCT (85 FR 19294, April 6, 2020), SFD (86 FR 50057,
September 7, 2021), and NES1 (89 FR 2832, January 14, 2024) projects,
NMFS accounted for the implementation of mitigation measures (e.g.,
shutdown procedures implemented when CIBWs entered or approached the
estimated Level B harassment zone) by applying an adjustment factor to
CIBW take estimates. This was based on the assumption that some Level B
harassment takes would likely be avoided based on required shutdowns
for CIBWs at the Level B harassment zone isopleths (see the Mitigation
section for more information). For the PCT project, NMFS compared the
number of observations of CIBW within estimated harassment zones at the
POA to the number of authorized takes for previous projects from 2008
to 2017 and found the percentage ranged from 12 to 59 percent with an
average of 36 percent (85 FR 19294, April 6, 2020). NMFS then applied
the highest percentage of previous potentially realized takes (i.e.,
number of CIBWs observed within estimated Level B harassment zones; 59
percent during the 2009-2010 season) to ensure potential takes of CIBWs
were fully evaluated. In doing so, NMFS assumed that approximately 59
percent of the takes calculated could be realized during PCT and SFD
construction (85 FR 19294, April 6, 2020; 86 FR 50057, September 7,
2021) and that 41 percent of the calculated CIBW Level B harassment
takes would be avoided by successful implementation of required
mitigation measures.
The POA calculated the adjustment for successful implementation of
mitigation measures for CTR using the percentage of potentially
realized takes for the PCT project (see table 6-20 in the POA's
application). The data from PCT Phase 1 and PCT Phase 2 most accurately
reflect the current marine mammal monitoring program, the current
program's effectiveness, and
[[Page 31781]]
CIBW occurrence in the CTR project area. Between the 2 phases of the
PCT project, 90 total Level B harassment takes were authorized and 53
were potentially realized, equating to an overall percentage of 59
percent. The SFD Project, during which only 7 percent of authorized
take was potentially realized, represents installation of only 12 piles
during a limited time period and does not represent the much higher
number of piles and longer construction timeframe anticipated for the
CTR project.
In the proposed rule (89 FR 85686, October 28, 2024), NMFS
concurred that the 59-percent adjustment accurately accounted for the
efficacy of the POA's marine mammal monitoring program and required
shutdown protocols, based on past performance. Between the publication
of the proposed rule and this final rule, POA submitted the final
monitoring report for the NES1 project, and those data have been
incorporated in this final rule. The sighting rates for CIBW at the POA
shown in table 13 have been adjusted based on the new data.
Additionally, the percentage of potentially realized takes from the
NES1 project was higher than previous projects at 68 percent (49 out of
72 authorized takes). NMFS, therefore, has applied the highest
previously observed take percentage as a conservative correction factor
and assumes that approximately 68 percent of the takes calculated for
CTR may actually be realized (table 18). Take by Level A harassment is
not anticipated or authorized for CIBWs because the POA will be
required to shut down activities when CIBWs approach and or enter the
Level B harassment zone, which in all cases is larger than the
estimated Level A harassment zones (see the Mitigation section for more
information).
Table 18--Calculated Level B Harassment Takes of CIBWs by Month, Year, and Activity\1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Apr May Jun Jul Aug \2\ Sep \2\ Oct \2\ Nov
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Year 1 \1\
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36-in vibratory installation \3\................................ 1.59 1.84 3.45 0.98 17.30 13.79 7.06 1.45
36-in vibratory removal \3\..................................... 0.24 0.12 0.27 0.08 1.48 1.01 0.89 0.49
72-in vibratory installation (attenuated)....................... 0.48 0.54 1.01 0.29 4.08 3.26 3.33 0.06
72-in vibratory installation (unattenuated) \4\................. 0.06 0.03 0.05 0.01 0.24 0.20 0.21 0.06
72-in impact installation (attenuated).......................... 2.35 3.36 7.11 1.97 31.93 24.48 24.02 3.62
72-in impact installation (unattenuated) \4\.................... 0.49 0.27 0.41 0.11 2.06 1.65 1.73 0.51
---------------------------------------------------------------------------------------
Year 1 total................................................ ......... ......... ......... ......... ......... ......... ......... 173
With 68% Correction Factor \5\.............................. ......... ......... ......... ......... ......... ......... ......... 118
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 2 \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in vibratory installation \3\................................ 1.91 1.54 2.87 0.82 14.42 11.49 5.88 1.45
36-in vibratory removal \3\..................................... 0.24 0.12 0.27 0.08 1.48 1.01 0.89 0.00
72-in vibratory installation (attenuated)....................... 0.48 0.44 0.81 0.23 4.08 2.87 2.94 0.42
72-in vibratory installation (unattenuated) \4\................. 0.06 0.03 0.05 0.01 0.24 0.20 0.21 0.06
72-in impact installation (attenuated).......................... 2.35 2.72 5.76 1.59 31.93 21.60 21.20 3.62
72-in impact installation (unattenuated) \4\.................... 0.49 0.27 0.41 0.11 2.06 1.65 1.73 0.51
---------------------------------------------------------------------------------------
Year 2 total................................................ ......... ......... ......... ......... ......... ......... ......... 156
With 68% Correction Factor \5\.............................. ......... ......... ......... ......... ......... ......... ......... 107
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 3 \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in vibratory installation \3\................................ 4.14 3.99 7.47 2.13 37.48 29.89 15.29 1.45
36-in vibratory removal \3\..................................... 0.24 0.35 0.81 0.24 2.96 2.02 0.89 0.49
72-in vibratory installation (attenuated)....................... 0.37 0.18 0.34 0.07 1.20 0.96 0.98 0.30
72-in vibratory installation (unattenuated) \4\................. 0.06 0.03 0.05 0.01 0.24 0.20 0.21 0.06
72-in impact installation (attenuated).......................... 1.83 1.12 2.37 0.47 9.42 7.22 7.09 2.59
72-in impact installation (unattenuated) \4\.................... 0.49 0.27 0.41 0.11 2.06 1.65 1.73 0.51
---------------------------------------------------------------------------------------
Year 3 total...........................
[…truncated; see source link]Indexed from Federal Register on July 15, 2025.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.