[Federal Register Volume 89, Number 189 (Monday, September 30, 2024)]
[Notices]
[Pages 79557-79568]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-22394]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XE225]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Army Corps of Engineers Baker 
Bay Pile Dike Repair Project

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
the Army Corps of Engineers (ACOE) to incidentally harass marine 
mammals during construction activities associated with the Baker Bay 
pile dike repair project in Baker Bay, Oregon. There are no changes 
from the proposed authorization in this final authorization.

DATES: This authorization is effective from August 1, 2025 to July 31, 
2026.

ADDRESSES: Electronic copies of the application and supporting 
documents, as well as a list of the references cited in this document, 
may be obtained online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-army-corps-engineers-baker-bay-pile-dike-repair-project-baker. In case of problems accessing these documents, 
please call the contact listed below.

FOR FURTHER INFORMATION CONTACT: Craig Cockrell, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the 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 September 8, 2022, NMFS received a request from the ACOE for an 
IHA to take marine mammals incidental to pile driving and removal at 
the mouth of the Columbia River in Oregon. Following NMFS' review of 
the application, the ACOE submitted two revised versions on March 4, 
2024 and May 1, 2024. The application was deemed adequate and complete 
on June 10, 2024. The ACOE's request is for take of eight species of 
marine mammals by Level B harassment and, for harbor seal (Phoca 
vitulina), Level A harassment. Neither ACOE nor NMFS expect serious 
injury or mortality to result from this activity and, therefore, an IHA 
is appropriate.

Description of Activity

    ACOE is planning to conduct pile dike repairs in the Baker Bay 
system, located in the Columbia River estuary. There are a variety of 
activities that will occur during this project. Take of marine mammals 
is expected to occur only during the construction of the material 
offload facility and the installation of the marker piles. Vibratory 
and impact pile driving will introduce underwater sounds that may 
result in take, by Level A and Level B harassment, of marine mammals. 
It is expected to take up to 12 non-consecutive days to complete the 
pile driving activities from August through October.
    A detailed description of the planned construction project is 
provided in the Federal Register notice for the proposed IHA (89 FR 
60385, July 25, 2024). Since that time, no changes have been made to 
the planned activities. Therefore, a detailed description is not 
provided here. Please refer to that Federal Register notice for the 
description of the specific activity.

Comments and Responses

    A notice of NMFS' proposal to issue an IHA to the ACOE was 
published in the Federal Register on July 25, 2024 (89 FR 60385). That 
notice described, in detail, the ACOE's activity, the marine mammal 
species that may be affected by the activity, and the anticipated 
effects on marine mammals. In that notice, we requested public input on 
the request for authorization described therein, our analyses, the 
proposed authorization, and any other aspect of the notice of proposed 
IHA, and requested that interested persons submit relevant information, 
suggestions, and comments. During the 30-day public comment period, 
NMFS did not receive any public comments.

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments)

[[Page 79558]]

and more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 1 lists all species or stocks for which take is expected and 
authorized for this activity and summarizes information related to the 
population or stock, including regulatory status under the MMPA and 
Endanger Species Act (ESA) and potential biological removal (PBR), 
where known. PBR is defined by the MMPA as the maximum number of 
animals, not including natural mortalities, that may be removed from a 
marine mammal stock while allowing that stock to reach or maintain its 
optimum sustainable population (as described in NMFS' SARs). While no 
serious injury or mortality is anticipated or 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. Pacific SARs. All values presented in table 1 are the most 
recent available at the time of publication (including from the draft 
2023 SARs) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                            Table 1--Species Likely Impacted by the Specified Activities \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/MMPA status;    Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \2\          abundance survey) \3\               SI \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae (baleen
 whale):
    Gray Whale......................  Eschrichtius robustus..  Eastern N Pacific......  -, -, N             26,960 (0.05, 25,849,         801        131
                                                                                                             2016).
  Family Balaenopteridae (rorquals)
    Humpback whale..................  Megaptera novaeangliae.  Central America/         E, D, Y             1,494 (0.171, 1,284,          3.5       14.9
                                                                Southern Mexico--CA/OR/                      2021).
                                                                WA.
                                                               Mainland Mexico--CA/OR/  T, D, Y             3,477 (0.101, 3,185,           43         22
                                                                WA.                                          2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer whale....................  Orcinus orca...........  West Coast Transient...  -, -, N             349 (N/A, 349, 2018)..        3.5        0.4
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Northern OR/WA Coast...  -, -, N             22,074 (0.391, 16,068,        161        3.2
                                                                                                             2022).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion................  Eumetopias jubatus.....  Eastern DPS............  -, -, N             36,308 (N/A, 36,308,        2,178       93.2
                                                                                                             2022).
    California sea lion.............  Zalophus californianus.  U.S....................  -, -, N             257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  OR/WA Coastal..........  -, -, N             UNK (UNK, UNK, 1999)..        UND       10.6
    Northern elephant seal..........  Mirounga angustirostris  CA Breeding............  -, -, N             187,386 (N/A, 85,369,       5,122       13.7
                                                                                                             2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on
  Taxonomy.
\2\ 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.
\3\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.

    A detailed description of the species likely to be affected by the 
Baker Bay pile dike project, including brief introductions to the 
species and relevant stocks as well as available information regarding 
population trends and threats, and information regarding local 
occurrence, were provided in the Federal Register notice for the 
proposed IHA (89 FR 60385, July 25, 2024); since that time, we are not 
aware of any changes in the status of these species and stocks; 
therefore, detailed descriptions are not provided here. Please refer to 
that Federal Register notice for these descriptions. Please also refer 
to NMFS' website (https://www.fisheries.noaa.gov/find-species) for 
generalized species accounts.

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

[[Page 79559]]

(behavioral response data, anatomical modeling, etc.). Subsequently, 
NMFS (2018) described generalized hearing ranges for these marine 
mammal hearing groups. Generalized hearing ranges were chosen based on 
the approximately 65-decibel (dB) threshold from the normalized 
composite audiograms, with the exception for lower limits for low-
frequency cetaceans where the lower bound was deemed to be biologically 
implausible and the lower bound from Southall et al. (2007) retained. 
Marine mammal hearing groups and their associated hearing ranges are 
provided in table 2.

                  Table 2--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
               Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen         7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,      150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true          275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus cruciger &
 L. australis).
Phocid pinnipeds (PW) (underwater) (true     50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea     60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al., 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from the ACOE's construction 
activities have the potential to result in behavioral harassment of 
marine mammals in the vicinity of the project area. The notice of 
proposed IHA (89 FR 60385, July 25, 2024) included a discussion of the 
effects of anthropogenic noise on marine mammals and the potential 
effects of underwater noise from the ACOE's construction on marine 
mammals and their habitat. That information and analysis is referenced 
in this final IHA determination and is not repeated here; please refer 
to the notice of proposed IHA (89 FR 60385, July 25, 2024).

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
authorized through the IHA, which will inform NMFS' consideration of 
``small numbers,'' the negligible impact determinations, and impacts on 
subsistence uses.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes will primarily be by Level B harassment, as use of 
the construction equipment (i.e., pile driving) has the potential to 
result in disruption of behavioral patterns for individual marine 
mammals. There is also some potential for auditory injury (Level A 
harassment) of phocids because predicted auditory injury zones are 
larger than for other species. The 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 to be authorized for this activity. Below we describe 
how the take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur Permanent Threshold Shift (PTS) of some 
degree (equated to Level A harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al. 2007, 2021; Ellison et al. 2012). Based 
on what the available science indicates and the practical need to use a 
threshold based on a metric that is both predictable and measurable for 
most activities, NMFS typically uses a generalized acoustic threshold 
based on received level to estimate the onset of behavioral harassment. 
NMFS generally predicts that marine mammals are likely to be 
behaviorally harassed in a manner considered to be Level B harassment 
when exposed to underwater anthropogenic noise above root-mean-

[[Page 79560]]

squared pressure received levels (RMS SPL) of 120 dB (referenced to 1 
micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile 
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by Temporary Threshold Shift (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 (conspecific communication, predators, prey) may 
result in changes in behavior patterns that will not otherwise occur.
    The ACOE's construction includes the use of continuous (vibratory 
pile driving) and impulsive (impact pile driving) sources, and 
therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa are 
applicable.
    Level A Harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0; 
Technical Guidance 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). The ACOE's 
construction includes the use of impulsive (impact pile driving) and 
non-impulsive (vibratory pile driving) sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1:Lpk,flat: 219 dB;    Cell 2:LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3:Lpk,flat: 230 dB;    Cell 4:LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5:Lpk,flat: 202 dB;    Cell 6:LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7:Lpk,flat: 218 dB;    Cell 8:LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9:Lpk,flat: 232 dB;    Cell 10:LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
  has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to reflect American
  National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
  incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
  ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
  generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
  the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
  be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
  it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the project. Marine 
mammals are expected to be affected via sound generated by the primary 
components of the project (i.e., impact pile driving and vibratory pile 
driving and removal). The maximum (underwater) area ensonified above 
the thresholds for behavioral harassment referenced above is 20.72 
km\2\ (12.87 mi\2\), and will consist of most of the mouth of the 
Columbia River immediately south of West Sand Island (See figure 1 in 
the proposed IHA 89 FR 60385, July 25, 2024). Additionally, vessel 
traffic in the project area may contribute to elevated background noise 
levels which may mask sounds produced by the project.
    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B x Log<INF>10</INF> (R<INF>1</INF>/R<INF>2</INF>),

where

TL = transmission loss in dB
B = transmission loss coefficient
R<INF>1</INF> = the distance of the modeled SPL from the driven 
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial 
measurement

    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive conditions including in-water structures and 
sediments. Spherical spreading occurs in a perfectly unobstructed 
(free-field) environment not limited by depth or water surface, 
resulting in a 6-dB reduction in sound level for each doubling of 
distance from the source (20*log[range]). Cylindrical spreading occurs 
in an environment in which sound propagation is bounded by the water 
surface and sea bottom, resulting in a reduction of 3 dB in sound level 
for each doubling of distance from the source (10*log[range]). A 
practical spreading value of 15 is often used under conditions, such as 
the project site, where water increases with depth as the receiver 
moves away from the shoreline, resulting in an expected propagation 
environment that will lie between spherical and cylindrical spreading 
loss conditions. Practical spreading loss is assumed here.
    The intensity of pile driving sounds is greatly influenced by 
factors such as the

[[Page 79561]]

type of piles, hammers, and the physical environment 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, the applicant and NMFS 
used acoustic monitoring data from other locations to develop proxy 
source levels for the various pile types, sizes and methods. The 
project includes vibratory and impact pile installation of steel pipe 
and sheet piles and vibratory removal of steel sheet piles. Source 
levels for 24-in steel pipe piles are used as a proxy for all steel 
piles that may be placed for marker piles of the dike system, though 
smaller piles may be used during the construction. NMFS consulted 
multiple sources to determine valid proxy source levels for the impact 
installation of sheet piles, as indicated in table 4. This is the best 
available data for sheet pile source levels and is based on 24-in sheet 
piles used for a project in California. Source levels for each pile 
size and driving method are presented in table 4.

                                          Table 4--Proxy Sound Source Levels for Pile Sizes and Driving Methods
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Proxy source level (at 10 m)
                                                                  --------------------------------------------------
               Pile size                          Method              dB RMS re        dB SEL re       dB peak re             Literature source
                                                                     1[micro]Pa    1[micro]Pa\2\sec    1[micro]Pa
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in.................................  Vibratory................             154              N/A              N/A  Navy 2015.
24-in sheet pile......................  Vibratory................             160              N/A              N/A  Caltrans 2020.
24-in.................................  Impact...................             189              178              203  Caltrans 2015.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    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 impact or vibratory 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 PTS. Inputs used in the 
optional User Spreadsheet tool are reported below (table 5). The 
resulting estimated Level A harassment isopleths and the Level B 
harassment isopleths are reported in table 6.

                  Table 5--User Spreadsheet Inputs for Calculating Level A Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                           Weighting
                                     Spreadsheet tab        factor       Number of    Number of      Activity
Pile size and installation method          used           adjustment    strikes per   piles per      duration
                                                             (kHz)          pile         day         (minutes)
----------------------------------------------------------------------------------------------------------------
24-in vibratory installation (MOF  A.1 Vibratory pile              2.5          N/A            8              20
 Option 2).                         driving.
24-in vibratory removal (MOF       A.1 Vibratory pile              2.5          N/A           16               5
 Option 2).                         driving.
24-in sheet pile vibratory         A.1 Vibratory pile              2.5          N/A           25              15
 installation (MOF Option 1).       driving.
24-in sheet pile vibratory         A.1 Vibratory pile              2.5          N/A           60               3
 removal (MOF Option 1).            driving.
24-in vibratory installation       A.1 Vibratory pile              2.5          N/A            8              15
 (Pile Markers).                    driving.
24-in impact installation (Pile    E.1 Impact pile                   2          225            5             N/A
 Markers).                          driving.
----------------------------------------------------------------------------------------------------------------


                          Table 6--Calculated Level A and Level B Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                          Level A harassment zone (m)
                                          ----------------------------------------------------------   Level B
                 Activity                      LF-         MF-         HF-                            harassment
                                            cetaceans   cetaceans   cetaceans   Phocids    Otariids    zone (m)
----------------------------------------------------------------------------------------------------------------
24-in Steel Pipe Pile Vibratory Install           4.5         0.4         6.6        2.7        0.2      1,847.8
 (MOF Option 2)..........................
24-in Steel Pipe Pile Vibratory Removal           2.8         0.3         4.2        1.7        0.1
 (MOF Option 2)..........................
24-in sheet pile vibratory installation          23.4         2.1        34.6       14.2        1.0      4,641.1
 (MOF Option 1)..........................
24-in sheet pile vibratory removal (MOF          12.2         1.1          18        7.4        0.5
 Option 1)...............................
24-in vibratory installation (Pile                3.7         0.3         5.5        2.3        0.2      1,847.8
 Markers)................................
24-in impact installation (Pile Markers).       501.4        17.8       597.2      268.3       19.5        857.7
----------------------------------------------------------------------------------------------------------------


[[Page 79562]]

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations. We describe how the information 
provided is synthesized to produce a quantitative estimate of the take 
that is reasonably likely to occur and authorized.
    When available, peer-reviewed scientific publications were used to 
estimate marine mammal abundance in the project area. Data from 
monitoring reports from the previous Sand Island Test Pile Project was 
used to calculate take for several species. However, scientific surveys 
and resulting data, such as population estimates, densities, and other 
quantitative information, are lacking for some species. The ACOE also 
gathered qualitative information from discussions with knowledgeable 
local people that frequent the mouth of the Columbia River. Assumptions 
regarding the size of expected groups of different species, and the 
frequency of occurrence of those groups, were made by the ACOE on the 
basis of the aforementioned information and are described for each 
species below.
    Since reliable densities are not available, the take numbers are 
based on the assumed occurrence of a given stock during the activity. 
The applicant used equation 1, below, to estimate take of killer whales 
and Steller sea lions, equation 2 to estimate take of humpback whale, 
harbor porpoise, California sea lions, and harbor seals, and neither 
equation for gray whale or Northern elephant seals. NMFS concurs with 
this method. The estimated take calculation for these/this species is 
explained in the relevant section below.

(1) Estimated Take = number of individuals in a group x groups per day 
x days of pile-related activity
(2) Estimated Take = total expected duration of the project (minutes) / 
total duration of the Sand Island Test Pile Project x the total number 
of animals of a given species observed during the Sand Island Test Pile 
Project
Gray Whale
    Historically gray whales have not frequented the mouth of the 
Columbia River. No gray whales were observed during monitoring 
activities of the Sand Island Test Pile Project (Hamer Environment L.P. 
2020). In August of 2020, an ACOE biologist observed two gray whales 
traveling upriver from the project site. Given this recent sighting and 
the temporal overlap of the project and the most recent sighting, NMFS 
authorized two takes of gray whales by Level B harassment.
    The largest Level A harassment zone for gray whales extends 513 m 
from the noise source (table 6). ACOE is planning to implement shutdown 
zones for low-frequency cetaceans that exceed the Level A harassment 
isopleth for all activities. Therefore, especially in combination with 
the already low occurrence of gray whales in the area, implementation 
of the shutdown zones is expected to eliminate the potential for take 
by Level A harassment of gray whale. Therefore, no take by Level A 
harassment is anticipated or authorized for humpback whales.
Humpback Whales
    Humpback whales have occurred in the lower Columbia River near the 
project area in recent years. Feeding groups have been using the mouth 
of the Columbia River as a foraging ground, arriving as early as mid-
June, and have been observed as late as mid-November with a peak of 
abundance coinciding with the peak abundance of forage fish in mid-
summer (The Columbian 2019). During pile driving activities of the Sand 
Island Test Pile Project, seven animals were observed (Hamer 
Environment L.P. 2020). The ACOE estimated take of humpback whales 
using equation 2 above resulting in a take estimate of 16 takes by 
Level B harassment (2277 (pile driving minutes for this activity)/1037 
(pile driving minutes for Sand Island Test Pile Project) x 7 observed 
animals). NMFS agrees with this approach and estimated take. As 
described above, NMFS anticipates that 42 percent of takes will occur 
to individuals of the Central America/Southern Mexico-CA/OR/WA stock 
and 58 percent of takes will occur to individuals of the Mainland 
Mexico-CA/OR/WA which will equate to seven and nine takes respectively.
    The largest Level A harassment zone for humpback whales extends 513 
m from the noise source (table 6). ACOE is planning to implement 
shutdown zones for low-frequency cetaceans that exceed the Level A 
harassment isopleth for all activities. Implementation of the shutdown 
zones is expected to eliminate the potential for take by Level A 
harassment of humpback whale. No take by Level A harassment is 
anticipated or authorized for humpback whales.
Killer Whale
    Use of the mouth of the Columbia River is rare for killer whales, 
but in recent years pods of killer whales have been observed in and 
around the mouth of the Columbia River. During the recent monitoring of 
the Sand Island Test Pile Project, no killer whales were observed 
(Hamer Environment L.P. 2020). Aerial seabird marine mammal surveys 
observed 0 killer whales in January 2011, 0 in February 2012, and 10 in 
September 2012 within an approximately 1,500 km2 range near the Mouth 
of the Columbia River (Adams 2014). A pod of transient killer whales 
was detected near the Astoria Bridge in May of 2018 (Frankowicz 2018) 
and in 2022 (Tomlinson 2022). The ACOE estimated the average group 
sizes from these past observations was seven. Based on the rare 
occurrence of killer whales in the project area, ACOE expects that one 
group of seven killer whales may occur during the 12 days of 
construction in the Level B harassment zone. NMFS concurs and 
authorized seven takes of killer whale by Level B harassment.
    The largest Level A harassment zone for killer whales extends 17.8 
m from the noise source (table 6). ACOE is planning to implement 
shutdown zones for mid-frequency cetaceans that exceed the Level A 
harassment isopleth for all activities. Implementation of the shutdown 
zones is expected to eliminate the potential for take by Level A 
harassment of killer whale. No take by Level A harassment is 
anticipated or authorized for killer whales.
Harbor Porpoise
    Harbor porpoises are regularly observed in the offshore waters near 
the mouth of the Columbia River and are known to occur there year-
round. Porpoise abundance peaks when anchovy (Engraulis mordax) 
abundance in the river and nearshore are highest, which is usually 
between April and August (Litz et al. 2008). Harbor porpoise tend to 
occur in groups of one to two individuals. During the recent monitoring 
of the Sand Island Test Pile Project, eight harbor porpoise were 
observed during construction activities (Hamer Environment L.P. 2020). 
Using equation 2 above, ACOE expects that 18 takes by Level B 
harassment will occur over the 12 days of pile driving (2277 (pile 
driving minutes for this activity)/1037 (pile driving minutes for Sand 
Island Test Pile Project) x 8 observed animals). NMFS agrees with this 
approach and authorized 18 takes by Level B harassment of harbor 
porpoise.
    The largest Level A harassment zone for harbor porpoise extends 597 
m from the noise source (table 6). ACOE is planning to implement 
shutdown zones for high-frequency cetaceans that exceed the Level A 
harassment isopleth for all activities, and it did not request take by

[[Page 79563]]

Level A harassment of harbor porpoise. For some activities (i.e., 
impact driving of 24-in piles), the shutdown zones extends farther than 
Protected Species Observers (PSO) may be able to reliably detect harbor 
porpoise. However, given the portion of the zone within which PSOs 
could reliably detect a harbor porpoise, the infrequency of harbor 
porpoise observations during the Sand Island Test Pile project 
monitoring, and harbor porpoise sensitivity to noise, no take by Level 
A harassment is anticipated or authorized for harbor porpoise.
Steller Sea Lion
    Steller sea lion occurrence was estimated using Washington 
Department of Fish and Wildlife haulout survey data from the South 
Jetty at the mouth of the Columbia River from 2000 to 2014. During the 
recent monitoring of the Sand Island Test Pile Project no Steller sea 
lions were observed (Hamer Environment L.P. 2020). Given the close 
proximity of the haulout, NMFS expects that Steller sea lions could 
occur near the project site. Occurrence was estimated using the monthly 
haulout numbers for the months when work will be occurring during the 
project. In August, the average number of Steller sea lions hauled out 
at the jetty was 72, and in October, the average number of sea lions at 
the jetty was 77. In August, construction will occur over 7-days, and 
in October, construction will occur over 5 days. Given the daily 
occurrence rates and days of in-water construction, and using equation 
1, the ACOE expects that 889 takes by Level B harassment will occur 
(daily occurrence (72 or 77) x days of activity), and NMFS authorized 
889 takes by Level B harassment of Steller sea lion.
    The largest Level A harassment zone for Steller sea lions extends 
19.5 m from the noise source (table 6). ACOE is planning to implement 
shutdown zones for otariids that exceed the Level A harassment isopleth 
for all activities. Implementation of the shutdown zones is expected to 
eliminate the potential for take by Level A harassment of Steller sea 
lion. No take by Level A harassment is anticipated or authorized for 
Steller sea lion.
California Sea Lion
    Similar to Steller sea lions, California sea lions use the South 
Jetty at the mouth of the Columbia River and make frequent trips inside 
the mouth of the river. Occurrence on the South Jetty peaks in summer 
and use in the fall and winter is more concentrated. During recent 
monitoring activities of the Sand Island Test Pile Project 59 animals 
were observed (Hamer Environment L.P. 2020). Using equation 2 above, 
ACOE expects that 144 takes by Level B harassment California sea lions 
will occur (2277 (pile driving minutes for this activity)/1037 (pile 
driving minutes for Sand Island Test Pile Project) x 59 observed 
animals), and NMFS authorized 144 takes by Level B harassment of 
California sea lion.
    The largest Level A harassment zone for California sea lions 
extends 19.5 m from the noise source (table 6). ACOE is planning to 
implement shutdown zones for otariids that exceed the Level A 
harassment isopleth for all activities. Implementation of the shutdown 
zones is expected to eliminate the potential for take by Level A 
harassment of California sea lion. No take by Level A harassment is 
anticipated or authorized for California sea lion.
Harbor Seal
    Harbor seals are the most abundant pinniped in Oregon and occur in 
the project are year-round. Large numbers of harbor seals move through 
the mouth of the Columbia River throughout the year and are expected to 
be present in the project area. During recent monitoring of the Sand 
Island Test Pile Project, a total of 309 harbor seals were observed 
during construction activities (Hamer Environment L.P. 2020). Take 
estimates were generated using equation 2 above and the Sand Island 
Pile Test Project monitoring results. ACOE expects that 679 takes by 
Level B harassment of harbor seals will occur during the project (2277 
(pile driving minutes for this activity)/1037 (pile driving minutes for 
Sand Island Test Pile Project) x 309 observed animals), and NMFS 
authorized 679 takes by Level B harassment of harbor seal.
    The Level A harassment zone for harbor seals during impact 
installation is 268 m (table 6). ACOE will implement a shutdown zone of 
150 m given the difficulty of observing harbor seals at greater 
distances and practicability concerns regarding efficient work 
production rates that will be associated with a larger shutdown zone 
(see Mitigation section). During impact installation ACOE expects that 
two harbor seals could be present in the Level A harassment zone. 
Therefore, over the 3 days of impact pile driving, NMFS anticipates, 
and authorized, six takes by Level A harassment (two takes per day * 3 
days = six takes by Level B harassment).
Northern Elephant Seal
    Northern elephant seals occur infrequently in the mouth of the 
Columbia River. Recent sightings of elephant seals have occurred in the 
fall and spring upriver from the project site. Although, no Northern 
elephant seals were observed during the Sand Island Test Pile Project 
(Hamer Environment L.P. 2020). ACOE expects that two animals may be 
present in the Level B harassment zone during the 12-days of 
construction, and NMFS authorized two takes by Level B harassment of 
elephant seal.
    The largest Level A harassment zone for Northern elephant seals 
extends 268 m from the noise source (table 6). ACOE is planning to 
implement shutdown zones for Northern elephant seal that exceed the 
Level A harassment isopleth for all activities. Implementation of the 
shutdown zones is expected to eliminate the potential for take by Level 
A harassment of Northern elephant seal. No take by Level A harassment 
is anticipated or authorized for Northern elephant seals.

                Table 7--Authorized Take by Level A and Level B Harassment, by Species and Stock
----------------------------------------------------------------------------------------------------------------
                                                      Stock
          Common name                 Stock         abundance     Level A     Level B    Total take   Take as a
                                                       \a\                                            percentage
----------------------------------------------------------------------------------------------------------------
Gray Whale....................  Eastern N               26,960           0           2            2           <1
                                 Pacific.
Humpback Whale................  Central America/         1,494           0           7            7           <1
                                 Southern Mexico-
                                 CA/OR/WA.
                                Mainland Mexico-         3,477           0           9            9           <1
                                 CA/OR/WA.
Killer Whale..................  West Coast                 349           0           7            7            2
                                 Transients.
Harbor Porpoise...............  Northern OR/WA          22,074           0          18           18           <1
                                 Coast.
Steller sea lion..............  Eastern.........        36,308           0         889          889          2.4
California Sea Lion...........  United States...       257,074           0         144          144           <1
Harbor Seal...................  OR/WA Coastal...           UKN           6         679          685          N/A

[[Page 79564]]

 
Northern Elephant Seal........  CA Breeding.....       187,386           0           2            2           <1
----------------------------------------------------------------------------------------------------------------
\a\ Stock size is best estimate of population (Nbest) according to NMFS 2022 Final Stock Assessment Reports and
  where apporiate the draft NMFS 2022 Final Stock Assessment Reports was used to estimate Nbest.

Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance. NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations.
    ACOE is required to implement the following mitigation measures:
    Implementation of Shutdown Zones--For all pile driving/removal 
activities, the ACOE will implement shutdowns within designated zones. 
The purpose of a shutdown zone is generally to define an area within 
which shutdown of activity will occur upon sighting of a marine mammal 
(or in anticipation of an animal entering the defined area). 
Implementation of shutdowns will be used to minimize the number and 
severity of takes from vibratory and impact pile driving and removal 
(table 8). For all pile driving/removal activities, a minimum 25-m 
shutdown zone will be established for pinnipeds and 50-m shutdown zone 
for cetaceans as outlined in the ACOE application for an IHA. For 
harbor seals, ACOE will implement a shutdown zone of 25 m given its 
concerns about potential frequent shutdowns that may occur with a 
larger shutdown zone in consideration of high occurrence of harbor 
seals in the project area. To minimize the potential of Level A 
harassment of harbor seals, NMFS recommended a shutdown zone of 150 m 
for harbor seals. ACOE concurred that this zone was practicable, and 
therefore, NMFS required a shutdown zone of 150 m for harbor seals. 
Shutdown zones for impact pile driving are based on the Level A 
harassment zones and therefore vary by marine mammal hearing group 
(table 8). The placement of PSOs during all pile driving activities 
(described in detail in the Monitoring and Reporting section) will 
ensure the full extent of shutdown zones are visible to PSOs.

                                              Table 8--Shutdown Zones During Pile Installation and Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                            Shutdown zones (m)
                                                                                 -----------------------------------------------------------------------
                   Activity                                 Pile size                                                              Northern
                                                                                      LF          MF          HF        Harbor     elephant    Otariids
                                                                                   cetaceans   cetaceans   cetaceans     seals       seal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation........................  24-in (pile markers)............          50          50          50          25          25          25
Vibratory Installation and removal............  24-in (MOF option 2)............          50          50          50          25          25          25
Vibratory Installation and removal............  24-in sheet pile (MOF option 1).          50          50          50          25          25          25
Impact Installation...........................  24-in (pile markers)............         510          50         600         150         270          25
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Monitoring for Level A and Level B Harassment--The ACOE has 
identified monitoring zones correlated with the Level B harassment 
zones. Monitoring zones provide utility for observing by establishing 
monitoring protocols for areas adjacent to the shutdown zones. 
Monitoring zones enable observers to be aware of and communicate the 
presence of marine mammals in the project area outside the shutdown 
zone and thus prepare for a potential cessation of activity should the 
animal enter the shutdown zone. PSOs will monitor the entire visible 
area to maintain the best sense of where animals are moving relative to 
the zone boundaries defined in table 8. Placement of PSOs on the 
shorelines around Sand Island will allow PSOs to observe marine mammals 
near the project area. While not required by this IHA, ACOE states that 
it may also place a PSO on a skiff near the project area if safe 
conditions allow.
    Soft Start--Soft-start procedures are used to provide additional 
protection to marine mammals by providing warning and/or giving marine 
mammals a chance to leave the area prior to the hammer operating at 
full capacity. For impact pile driving, contractors will be required to 
provide an initial set of three strikes at reduced energy, followed by 
a 30-second waiting period, then two subsequent reduced-energy strike 
sets. Soft start will be implemented at the start of each day's impact 
pile driving and at any time following cessation of impact pile driving 
for a period of 30 minutes or longer. Soft start is not required during 
vibratory pile driving and removal activities.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving/removal of 
30 minutes or longer occurs, PSOs will observe the shutdown and 
monitoring zones for a period of 30

[[Page 79565]]

minutes. The shutdown zone will be considered cleared when a marine 
mammal has not been observed within the zone for that 30-minute period. 
If a marine mammal is observed within the shutdown zone, a soft-start 
cannot proceed until the animal has left the zone or has not been 
observed for 15 minutes. If the monitoring zone has been observed for 
30 minutes and marine mammals are not present within the zone, soft-
start procedures can commence and work can continue. Pre-start 
clearance monitoring must be conducted during periods of visibility 
sufficient for the lead PSO to determine that the shutdown zones, 
indicated in table 9, are clear of marine mammals. When a marine mammal 
for which take by Level B harassment is authorized is present in the 
Level B harassment zone, activities may begin. If work ceases for more 
than 30 minutes, the pre-activity monitoring of both the monitoring 
zone and shutdown zone will commence.
    Based on our evaluation of the applicant's measures, NMFS has 
determined that the mitigation measures provide the means of effecting 
the least practicable impact on the affected species or stocks and 
their habitat, paying particular attention to rookeries, mating 
grounds, and areas of similar significance.

Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
    <bullet> Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
    <bullet> How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
    <bullet> Mitigation and monitoring effectiveness.

Visual Monitoring

    Monitoring shall be conducted by NMFS-approved observers in 
accordance with section 5 of the IHA. Trained observers shall be placed 
from the best vantage point(s) practicable to monitor for marine 
mammals and implement shutdown or delay procedures when applicable 
through communication with the equipment operator. Observer training 
must be provided prior to project start, and shall include instruction 
on species identification (sufficient to distinguish the species in the 
project area), description and categorization of observed behaviors and 
interpretation of behaviors that may be construed as being reactions to 
the specified activity, proper completion of data forms, and other 
basic components of biological monitoring, including tracking of 
observed animals or groups of animals such that repeat sound exposures 
may be attributed to individuals (to the extent possible).
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after pile driving/removal activities. In addition, observers 
shall record all incidents of marine mammal occurrence, regardless of 
distance from activity, and shall document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving/
removal activities include the time to install or remove a single pile 
or series of piles, as long as the time elapsed between uses of the 
pile driving equipment is no more than 30 minutes.
    A minimum of two PSO will be on duty during all in-water 
construction activities. Locations from which PSOs will be able to 
monitor for marine mammals are readily available from the shore of Sand 
Island. PSOs will monitor for marine mammals entering the harassment 
zones.
    PSOs will scan the waters using binoculars or spotting scopes and 
will use a handheld range-finder device to verify the distance to each 
sighting from the project site. PSOs will be placed at the best vantage 
point(s) practicable to monitor for marine mammals and implement 
shutdown/delay procedures when applicable by calling for the shutdown 
to the hammer operator via a radio.
    The ACOE will adhere to the following observer qualifications:
    (i) PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor) and have no other assigned tasks 
during monitoring periods;
    (ii) At least one PSO must have prior experience performing the 
duties of a PSO during construction activity pursuant to a NMFS-issued 
incidental take authorization;
    (iii) Other PSOs may substitute other relevant experience, 
education (degree in biological science or related field), or training 
for prior experience performing the duties of a PSO during construction 
activity pursuant to a NMFS-issued incidental take authorization;
    (iv) Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator must be designated. The lead 
observer must have prior experience performing the duties of a PSO 
during construction activity pursuant to a NMFS-issued incidental take 
authorization; and
    (v) PSOs must be approved by NMFS prior to beginning any activity 
subject to this IHA.
    Additional recommended observer qualifications include:
    <bullet> Ability to conduct field observations and collect data 
according to assigned protocols;
    <bullet> Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
    <bullet> Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    <bullet> Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates and times when in-water construction

[[Page 79566]]

activities were suspended to avoid potential incidental injury from 
construction sound of marine mammals observed within a defined shutdown 
zone; and marine mammal behavior; and
    <bullet> Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.

Reporting

    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. It will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the report must include:
    <bullet> Dates and times (begin and end) of all marine mammal 
monitoring.
    <bullet> Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact driving) and for each pile or 
total number of strikes for each pile (impact driving).
    <bullet> PSO locations during marine mammal monitoring.
    <bullet> Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance.
    <bullet> Upon observation of a marine mammal, the following 
information: Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting; time of sighting; identification of the 
animal(s) (e.g., genus/species, lowest possible taxonomic level, or 
unidentified), PSO confidence in identification, and the composition of 
the group if there is a mix of species; distance and bearing of each 
marine mammal observed relative to the pile being driven for each 
sighting (if pile driving was occurring at time of sighting); estimated 
number of animals (min/max/best estimate); estimated number of animals 
by cohort (adults, juveniles, neonates, group composition, etc.); 
animal's closest point of approach and estimated time spent within the 
harassment zone; description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching).
    <bullet> Number of marine mammals detected within the harassment 
zones, by species.
    <bullet> Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    If no comments are received from NMFS within 30 days, the draft 
final report will constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the Holder must report the 
incident to the Office of Protected Resources (OPR), NMFS and to the 
West Coast regional stranding network as soon as feasible. If the death 
or injury was clearly caused by the specified activity, the Holder must 
immediately cease the activities until NMFS OPR is able to review the 
circumstances of the incident and determine what, if any, additional 
measures are appropriate to ensure compliance with the terms of this 
IHA. The Holder must not resume their activities until notified by 
NMFS. The report must include the following information:
    <bullet> Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    <bullet> Species identification (if known) or description of the 
animal(s) involved;
    <bullet> Condition of the animal(s) (including carcass condition if 
the animal is dead);
    <bullet> Observed behaviors of the animal(s), if alive;
    <bullet> If available, photographs or video footage of the 
animal(s); and
    <bullet> General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the majority of our analysis applies to all 
the species listed in table 7, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, they are described independently in the analysis below.
    Pile driving and removal activities associated with the project as 
outlined previously, have the potential to disturb or displace marine 
mammals. Specifically, the specified activities may result in take, in 
the form of Level A harassment and Level B harassment from underwater 
sounds generated from pile driving and removal. Potential takes could 
occur if individuals of these species are present in zones ensonified 
above the thresholds for Level A or Level B harassment identified above 
when these activities are underway.
    Take by Level A and Level B harassment will be due to potential 
behavioral disturbance, TTS, and PTS. No serious injury or mortality is 
anticipated or authorized given the nature of the activity and measures 
designed to minimize the possibility of injury to marine mammals. Take 
by Level A harassment is only anticipated for harbor seals. The 
potential for

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harassment is minimized through the construction method (i.e., use of 
direct pull removal or vibratory methods to the extent practical) and 
the implementation of the mitigation measures (see Mitigation section).
    Behavioral responses of marine mammals to pile driving and removal 
at the project site, if any, are expected to be mild and temporary. 
Marine mammals within the Level B harassment zone may not show any 
visual cues they are disturbed by activities or could become alert, 
avoid the area, leave the area, or display other mild responses that 
are not observable such as changes in vocalization patterns. Given the 
limited number of piles to be installed or extracted per day and that 
pile driving and removal will occur across a maximum of 12 days within 
the 12-month authorization period, any harassment will be temporary.
    In addition to the expected effects resulting from Level B 
harassment, we anticipate that harbor seals may sustain some limited 
Level A harassment in the form of PTS. However, any PTS is expected to 
be of a small degree (i.e., minor degradation of hearing capabilities 
within regions of hearing that align most completely with the energy 
produced by pile driving (below 2 kHz)) because animals would need to 
be exposed to higher levels and/or longer duration than are expected to 
occur here in order to incur any more than a small degree of PTS. If 
hearing impairment occurs, it is most likely that the affected animal 
would lose a few decibels in its hearing sensitivity, which in most 
cases is not likely to meaningfully affect its ability to forage and 
communicate with conspecifics, as it would be minor and not in the 
region of greatest hearing sensitivity.
    Additionally, and as noted previously, some subset of the 
individuals that are behaviorally harassed could also simultaneously 
incur some small degree of TTS for a short duration of time. Because of 
the small degree anticipated, though, any PTS or TTS potentially 
incurred here would not be expected to adversely impact individual 
fitness, let alone annual rates of recruitment or survival.
    The project also is not expected to have significant adverse 
effects on affected marine mammals' habitat. The project activities 
will not modify existing marine mammal habitat for a significant amount 
of time. The activities may cause some fish or invertebrates to leave 
the area of disturbance, thus temporarily impacting marine mammals' 
foraging opportunities in a limited portion of the foraging range; but, 
because of the short duration of the activities, the relatively small 
area of the habitat that may be affected, and the availability of 
nearby habitat of similar or higher value, the impacts to marine mammal 
habitat are not expected to cause significant or long-term negative 
consequences.
    A large portion of the west coast, including the mouth of the 
Columbia River, has been identified as a biologically important area 
(BIA) for gray whale feeding (Calambokidis et al. 2024). As described 
above, the presence of gray whales in the project area is rare, and the 
area of overlap of the project with the feeding BIA affected is small 
compared to the overall size of the BIA. The gray whale feeding BIA is 
active from June through November while the project is scheduled to 
occur between August and October, resulting in only three months of 
overlap with the project and 3 months when the BIA is active but ACOE 
will not be conducting work. Additionally, pile driving associated with 
the project is expected to take only 12 days, further reducing the 
temporal overlap with the BIA. Therefore, take of gray whales using 
this feeding BIA, given both the small footprint of the activity 
relative to the BIA, and the scope and nature of the anticipated 
impacts of pile driving exposure, is not anticipated to impact the 
reproduction or survival of any individuals.
    In summary and as described above, the following factors primarily 
support our determination that the impacts resulting from this activity 
are not expected to adversely affect any of the species or stocks 
through effects on annual rates of recruitment or survival:
    <bullet> No serious injury or mortality is anticipated or 
authorized;
    <bullet> Any take by Level A harassment (harbor seals, only) is 
anticipated to result in slight PTS within the lower frequencies 
associated with pile driving;
    <bullet> The anticipated incidents of Level B harassment will 
consist of, at worst, temporary modifications in behavior that would 
not result in fitness impacts to individuals;
    <bullet> The area impacted by the specified activity is very small 
relative to the overall habitat ranges of all stocks, and does not 
overlap ESA-designated critical habitat. While impacts will occur 
within an area that is important for gray whale feeding, because of the 
small footprint of the activity relative to the feeding area, the 
limited temporal overlap of the activity and the feeding period, and 
the scope and nature of the anticipated impacts of pile driving 
exposure, we do not expect impacts to the reproduction or survival of 
any individuals; and
    <bullet> ACOE will implement mitigation measures, such as soft-
starts for impact pile driving and shut downs, to minimize the numbers 
of marine mammals exposed to injurious levels of sound, and to ensure 
that take by Level A harassment, is at most, a small degree of PTS.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the monitoring and mitigation 
measures, NMFS finds that the total marine mammal take from the 
activity will have a negligible impact on all affected marine mammal 
species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    Table 7 demonstrates the number of animals that NMFS anticipates 
could be taken by Level A and Level B harassment for the work. Our 
analysis shows that at most 2.4 percent of each affected stock could be 
taken by harassment. The numbers of animals to be taken for these 
stocks will be considered small relative to the relevant stock's 
abundances, even if each estimated taking occurred to a new individual, 
which is an unlikely scenario.
    Based on the analysis contained herein of the activity (including 
the mitigation and monitoring measures) and the anticipated take of 
marine mammals, NMFS finds that small numbers of marine mammals will be 
taken relative to the population size of the affected species or 
stocks.

Endangered Species Act

    Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.) 
requires that each Federal agency insure that any action it

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authorizes, funds, or carries out is not likely to jeopardize the 
continued existence of any endangered or threatened species or result 
in the destruction or adverse modification of designated critical 
habitat. To ensure ESA compliance for the issuance of IHAs, NMFS 
consults internally whenever we propose to authorize take for 
endangered or threatened species, in this case with the West Coast 
Regional Office.
    Two DPSs of humpback whale (Central America/Southern Mexico-CA/OR/
WA and Mainland Mexico-CA/OR/WA) occur in the project area and are 
listed as endangered and threatened, respectively, under the ESA. The 
NMFS West Coast Regional OPR Division issued a Biological Opinion on 
September 11, 2025 under section 7 of the ESA, on the issuance of an 
IHA to the ACOE under section 101(a)(5)(D) of the MMPA by the NMFS 
Permits and Conservation Division. The Biological Opinion concluded 
that the action is not likely to jeopardize the continued existence of 
Central America/Southern Mexico-CA/OR/WA and Mainland Mexico-CA/OR/WA 
humpback whales and is not likely to destroy or adversely modify their 
critical habitat.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must evaluate our proposed action the issuance of an IHA and 
alternatives with respect to potential impacts on the human 
environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or 
mortality) of the Companion Manual for NAO 216-6A, which do not 
individually or cumulatively have the potential for significant impacts 
on the quality of the human environment and for which we have not 
identified any extraordinary circumstances that would preclude this 
categorical exclusion. Accordingly, NMFS has determined that the 
issuance of this IHA qualifies to be categorically excluded from 
further NEPA review.

Authorization

    NMFS has issued an IHA to the ACOE for the potential harassment of 
small numbers of eight marine mammal species incidental to the pile 
dike repair project in Baker Bay, Oregon, that includes the previously 
explained mitigation, monitoring and reporting requirements.

    Dated: September 25, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-22394 Filed 9-27-24; 8:45 am]
BILLING CODE 3510-22-P