Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to U.S. Coast Guard Construction in Florence, Oregon, 13582-13592 [2025-04995]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 90, Number 56 (Tuesday, March 25, 2025)]
[Notices]
[Pages 13582-13592]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-04995]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XE693]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to U.S. Coast Guard Construction in 
Florence, Oregon

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 U.S. Coast Guard (USCG) to incidentally harass marine mammals 
during pile driving activities associated with Station Siuslaw River 
construction project in Florence, Oregon.

DATES: The authorization is effective from November 1, 2025 through 
October 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-us-coast-guards-station-siuslaw-river-construction-project. In case of problems accessing these documents, 
please call the contact listed below.

FOR FURTHER INFORMATION CONTACT: Jenna Harlacher, 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

[[Page 13583]]

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 used above are included in the relevant sections below 
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS 
regulations at 50 CFR 216.103.

Summary of Request

    On October 26, 2023, NMFS received a request from the USCG for an 
IHA to take marine mammals incidental to pile driving activity 
associated with the Station Siuslaw River construction project in 
Florence, Oregon. Following NMFS' review of the application, we 
received a revised version of the application on April 18, 2024. After 
finalizing construction details, the USCG submitted revised versions on 
July 16, 2024 and October 16, 2024, followed by a final revised version 
on November 18, 2024, which was deemed adequate and complete on 
December 5, 2024. USCG's request is for take of harbor seal, California 
sea lion, Steller sea lion, and harbor porpoise by Level B harassment, 
and for harbor seal and harbor porpoise, Level A harassment. Neither 
USCG nor NMFS expect serious injury or mortality to result from this 
activity and, therefore, an IHA is appropriate.

Description of Activity

Overview

    The USCG requested an IHA to correct shoreline erosion and replace 
the covered mooring and appurtenant structures at USCG Station Siuslaw 
River in Florence, Oregon (figure 1). This two-phased project entails 
both onshore and in-water construction activities including site 
preparation, demolition, shoreline stabilization measures, pile removal 
and installation, and overwater construction. Phase 1 includes onshore 
infrastructure improvements, sitework and shoreline stabilization, and 
phase 2 includes overwater and in-water construction including all pile 
install and removal.
    The only part of the project that may result in Level A and Level B 
harassment of marine mammals, and further analyzed in this notice, are 
the in-water construction activities associated with vibratory and 
impact pile driving (phase 2). The USCG plans to remove 71 timber piles 
via vibratory driving and to install 79 total piles via vibratory and 
impact driving with an estimated 48 total days of pile removal and 
install. USCG plans to install 16-inch (in) (40.6 centimeters (cm)) to 
20-in (50.8 cm) steel pipe piles, and/or 14-in (35.6 cm) H-piles for 
their new infrastructure. Pile driving will only occur within the 
Oregon Department of Fish and Wildlife (ODFW) approved in-water work 
window; however the IHA will have a 1-year period of effectiveness.
    A detailed description of the planned construction project is 
provided in the Federal Register notice for the proposed IHA (90 FR 
7082, January 21, 2025). Since that time, no changes have been made to 
the planned construction 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 USCG was published in 
the Federal Register on January 21, 2025 (90 FR 7082). That notice 
described, in detail, USCG's activities, the marine mammal species that 
may be affected by the activities, 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. This proposed notice was available for a 30-
day public comment period. 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) 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 
Endangered Species Act (ESA) and potential biological removal (PBR), 
where known. PBR is defined by the MMPA as the maximum number of 
animals, not including natural mortalities, that may be removed from a 
marine mammal stock while allowing that stock to reach or maintain its 
optimum sustainable population (as described in NMFS' SARs). While no 
serious injury or mortality is anticipated or authorized here, PBR and 
annual serious injury and mortality (M/SI) 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 Marine Mammal 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.

[[Page 13584]]



                     Table 1--Marine Mammal Species \1\ Likely To Occur Near the Project Area That May Be Taken by USCG's Activities
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                                                                                         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\
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                                                  Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocoenidae (porpoises):
    Harbor Porpoise.................  Phocoena phocoena......  Central Oregon \5\.....  -, -, N             7,492 (0.421, 5,332,           53          0
                                                                                                             2022).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    CA Sea Lion.....................  Zalophus californianus.  U.S....................  -, -, N             257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Steller Sea Lion \6\............  Eumetopias jubatus.....  Eastern................  -, -, N             36,308 (N/A, 36,308,        2,178       93.2
                                                                                                             2022).
Family Phocidae (earless seals):
    Harbor Seal.....................  Phoca vitulina.........  OR/WA Coastal..........  -, -, N             UNK (UNK, UNK, 1999)..        UND       10.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)).
\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.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (commercial
  fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated
  with estimated mortality due to commercial fisheries is presented in some cases.
\5\New stock in 2023 SARs.
\6\Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the United
  States only.

    All species that could potentially occur in the project areas are 
included in section 3 of the IHA application on page 12. While killer 
whales (Orcinus orca), humpback whales (Megaptera novaeangliae), and 
gray whales (Eschrichtius robustus) have been sighted off the Oregon 
coast, the USCG's project is located in the Siuslaw River where these 
species do not occur. Therefore, the temporal and/or spatial occurrence 
of these species is such that take is not expected to occur, and they 
are not discussed further beyond the explanation provided here and in 
the USCG's application. For more details on the species that are likely 
to occur near the project area and may be taken by USCG's activities, 
see sections 3 and 4 of USCG's IHA application, the SARs, and NMFS' 
website.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Generalized hearing ranges were 
chosen based on the ~65 decibel (dB) threshold from composite 
audiograms, previous analyses in NMFS (2018), and/or data from Southall 
et al. (2007) and Southall et al. (2019). We note that the names of two 
hearing groups and the generalized hearing ranges of all marine mammal 
hearing groups have been recently updated (NMFS, 2024) as reflected 
below in table 2.

                  Table 2--Marine Mammal Hearing Groups
                              [NMFS, 2024]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 36 kHz.
 whales).
High-frequency (HF) cetaceans          150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
Very High-frequency (VHF) cetaceans    200 Hz to 165 kHz.
 (true porpoises, Kogia, river
 dolphins, Cephalorhynchid,
 Lagenorhynchus cruciger & L.
 australis).
Phocid pinnipeds (PW) (underwater)     40 Hz to 90 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 68 kHz.
 (sea 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 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.


[[Page 13585]]

    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2024) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from USCG's construction activities 
have the potential to result in harassment of marine mammals in the 
vicinity of the project area. The notice of proposed IHA (90 FR 7082, 
January 21, 2025) included a discussion of the effects of anthropogenic 
noise on marine mammals and the potential effects of underwater noise 
from the USCG's pile driving activities on marine mammals and their 
habitat. That information and analysis is referenced in the notice and 
is not repeated here; please refer to the notice of the proposed IHA 
(90 FR 7082, January 21, 2025).

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 acoustic sources (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) 
to result, primarily for very high frequency species and phocids 
because predicted auditory injury zones are larger than for high-
frequency species and otariids. Auditory injury is unlikely to occur 
for high-frequency species and otariids. 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 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 criteria above which NMFS believes the best 
available science indicates marine mammals will likely be behaviorally 
harassed or incur some degree of auditory injury; (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 Criteria

    NMFS recommends the use of acoustic criteria that identify the 
received level of underwater sound above which exposed marine mammals 
will be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur auditory injury of some degree (equated 
to Level A harassment). We note that the criteria for auditory injury, 
as well as the names of two hearing groups, have been recently updated 
(NMFS 2024) as reflected below in the Level A Harassment section.
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 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 would not otherwise occur.
    USCG's planned activity 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' Updated Technical Guidance for Assessing 
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to 
assess auditory injury (Level A harassment) to five different 
underwater marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). USCG's planned activity includes the use 
of impulsive (impact pile driving) and non-impulsive (vibratory pile 
driving) sources.
    The 2024 Updated Technical Guidance criteria include both updated 
thresholds and updated weighting functions for each hearing group. The 
thresholds are provided in table 3 below. The references, analysis, and 
methodology used in the development of the criteria are described in 
NMFS' 2024 Updated Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools.

[[Page 13586]]



                          Table 3--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
                                               Auditory injury onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 222 dB;   Cell 2: LE,LF,24h: 197 dB.
                                          LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans..........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,HF,24h: 201 dB.
                                          LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans....  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,VHF,24h: 181 dB.
                                          LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 223 dB;   Cell 8: LE,PW,24h: 195 dB.
                                          LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9 Lpk,flat: 230 dB;    Cell 10: LE,OW,24h: 199 dB.
                                          LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
  calculating auditory injury onset. If a non-impulsive sound has the potential of exceeding the peak sound
  pressure level criteria associated with impulsive sounds, the PK SPL criteria are recommended for
  consideration for non-impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
  exposure level (LE,p) has a reference value of 1 [mu]Pa\2\s. In this Table, criteria are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO 2017; ISO 2020). The
  subscript ``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within
  the generalized hearing range of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated
  with cumulative sound exposure level criteria indicates the designated marine mammal auditory weighting
  function (LF, HF, and VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is
  24 hours. The weighted cumulative sound exposure level criteria 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 criteria 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 USCG opted to perform its own acoustic modeling for the Level A 
and Level B harassment isopleths using dBSea, a software developed by 
Marshall Day Acoustics for the modeling of underwater sound propagation 
in a variety of environments. Use of this model allowed USCG to 
incorporate site-specific information, therefore providing more 
accurate results than other more generalized tools. dBSea was also used 
in a previous construction project by the USCG (88 FR 77985, November 
11, 2023). NMFS has reviewed USCG's modeling and determined that it is 
acceptable for use here.
    Marshall Day Acoustics built the model by importing bathymetry data 
and placing noise sources in the environment. Each source can consist 
of equipment chosen from either the standard or the user-defined 
databases. Noise mitigation methods may also be included. The user has 
control over the seabed and water properties including sound speed 
profile, temperature, salinity, and current. To examine results in more 
detail, the model allows users to plot noise levels in cross sections, 
or extract a detailed spectrum at any point in the calculation area. 
USCG calculated noise levels to the deepest depth within the project 
area.
    USCG derived representative acoustic modeling scenarios based on 
descriptions of the expected construction activities through 
consultations between the USCG project design and engineering teams. 
The team modeled activities that are expected to result in take of 
marine mammals (i.e., in-water pile driving and removal) at a location 
with characteristics representative of the project site. The USCG 
modeled the full range of potential water depths in the project area at 
a single representative location. As described in the Detailed 
Description of the Specified Activity section of the notice of the 
proposed IHA (90 FR 7082, January 21, 2025), USCG may install a variety 
of pile types and sizes, and the exact pile sizes have not yet been 
determined. However, in an effort to avoid underestimating potential 
impacts to marine mammals, USCG conducted its analysis using the 
maximum possible pile size for each project use. Table 4 lists the 
sound source levels for each activity that USCG incorporated into the 
model. Table 5 shows the model-estimated Level A and Level B harassment 
isopleths for the planned activities. Please refer to the Acoustic 
Assessment included in USCG's IHA application for additional details on 
the modeling principles and assumptions and a summary of construction 
and operational scenarios included in the underwater acoustic modeling 
analysis.

           Table 4--Estimates of Underwater Sound Sources * Generated During Vibratory and Impact Pile Installation and Vibratory Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
           Pile driving method                Pile type and size          db RMS          dB peak         db SEL                   Reference
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact installation.....................  Steel pipe pile 24-in.....             194             207             178  Caltrans 2020.
                                          H-pile....................             178             200             166  Caltrans 2020.
Vibratory installation..................  Steel pipe pile 24-in.....             165  ..............  ..............  Caltrans 2020.
Vibratory removal.......................  Timber....................             162  ..............  ..............  Caltrans 2020.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.
* All sound levels are referenced at 10 m.


[[Page 13587]]


                                Table 5--Level A and Level B Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                               Level A isopleth (m)
                  Size and type                  ------------------------------------------------     Level B
                                                        VHF           Phocids        Otariids      isopleth (m)
----------------------------------------------------------------------------------------------------------------
                                       Vibratory Installation and Removal
----------------------------------------------------------------------------------------------------------------
24-in steel pipe pile installation..............              58              39              17           1,117
Timber removal..................................              16              14  ..............           1,106
----------------------------------------------------------------------------------------------------------------
                                               Impact Installation
----------------------------------------------------------------------------------------------------------------
24-in steel pipe pile...........................             335             256              95             717
H-pile..........................................              96              35              18             110
----------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence and Take Calculation and 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 and describe how the information 
provided is synthesized to produce a quantitative estimate of the take 
that is reasonably likely to occur and authorized. The USCG uses marine 
mammal species densities from the Pacific Navy Marine Species Density 
Database to estimate take for marine mammals. This database 
incorporates analyzed literature and research for marine mammal density 
estimates per season for regions throughout the United States, and the 
USCG based their take estimates on regionally available population 
density estimates and site-specific knowledge. Although this database 
provides densities for all species present in the action area, the 
densities are based on offshore abundance and not directly relevant to 
occurrence within in the Siuslaw River. Following careful review of the 
analysis presented by the USCG in its application, including marine 
mammal occurrence data, NMFS has determined that different information 
inputs than those selected by the USCG, represent the best available 
scientific information for marine mammal abundance in the action area. 
These selections are discussed in greater detail below.
    For all species, the numbers of individuals are based on average 
group sizes from Bates et al. (2023) that described marine mammal 
occurrences near Coos Bay, Oregon in 2014 and 2015. While Coos Bay is 
south of the action area, this area is more representative of the 
action area within the Siuslaw River than the offshore data in the 
application. We derived potential take estimates from the average group 
sizes recorded over the specified period in Bates et al. (2023) and 
used the occurrences of these sightings during the surveys, along with 
sightings in OBIS-SEAMAP around the action area, to estimate our 
sighing rates in the project vicinity (table 6).

                Table 6--Species Rate in the Action Area
------------------------------------------------------------------------
                                                      Sighting rate for
           Species             Average group size        action area
------------------------------------------------------------------------
California sea lion.........                   1.4  Group every other
                                                     day.
Steller sea lion............                   1.8  Group every other
                                                     day.
Harbor seal.................                     1  2 groups/day.
Harbor porpoise.............                   1.3  Group every other
                                                     day.
------------------------------------------------------------------------

    To calculate the total estimated takes by Level B harassment, we 
multiplied the estimated days of activity by the associated average 
group size and sighting rate for each species (table 6). There is also 
some potential for take by Level A harassment of harbor seal and harbor 
porpoise during impact pile driving due to the largest zones of each 
species being greater than the shutdown zones and because of the 
cryptic nature and assumed lower detectability of these species.
    Based on the relative proportion of the area expected to be 
ensonified above the Level A harassment threshold for phocids from 
impact pile driving (approximately 0.14 square kilometers (km\2\)) to 
the area ensonified above the Level B harassment threshold (0.59 km\2\ 
for impact pile driving), we estimated that of the total number of 
harbor seals that may be located within the greater Level B harassment 
zone, approximately 24 percent will enter the smaller Level A 
harassment zone (256 m) and stay in the zone long enough to incur 
auditory injury. Thus, we assume that 24 percent of the total estimated 
takes of harbor seals (96 individuals; see table 7) will be by Level A 
harassment. Therefore, we are authorizing 23 takes of harbor seals by 
Level A harassment and 73 takes by Level B harassment (table 7). Take 
by Level A harassment for harbor porpoise was calculated in the same 
way as for harbor seals. For otarriids, we are not authorizing take by 
Level A harassment as the shutdown zones are much larger than the Level 
A harassment zones for most activities, and the likely occurrence of 
otariids in the action area is much lower than for harbor porpoise and 
harbor seals.

[[Page 13588]]



                  Table 7--Take of Marine Mammals by Level A and Level B Harassment by Species and Stock and Percent of Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Take by Level A   Take by Level B                    Percent of
                     Species                                     Stock                   harassment        harassment       Total take      stock taken
--------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lion.............................  U.S...............................                 0                34              34            <0.1
Steller sea lion................................  Eastern...........................                 0                43              43             0.1
Harbor seal.....................................  Oregon/Washington Coast...........                23                73              96             0.4
Harbor porpoise.................................  Central Oregon....................                11                20              31             0.4
--------------------------------------------------------------------------------------------------------------------------------------------------------

Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). 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, and impact on operations.
    USCG must ensure that construction supervisors and crews, the 
monitoring team, and relevant USCG staff are trained prior to the start 
of all pile driving activity, so that responsibilities, communication 
procedures, monitoring protocols, and operational procedures are 
clearly understood. New personnel joining during the project must be 
trained prior to commencing work.

Pre- and Post-Activity Monitoring

     Monitoring must take place from 30 minutes prior to 
initiation of pile driving activity (i.e., pre-clearance monitoring) 
through 30 minutes post-completion of pile driving activity; and
     Pre-start clearance monitoring must be conducted during 
periods of visibility sufficient for the lead protected species 
observer (PSO) to determine that the shutdown zones indicated in table 
8 are clear of marine mammals. Pile driving may commence following 30 
minutes of observation when the determination is made that the shutdown 
zones are clear of marine mammals.

Soft Start

    USCG must use soft start techniques when impact pile driving. Soft 
start requires contractors 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. A soft start must be implemented 
at the start of each day's impact pile driving and at any time 
following cessation of impact pile driving for a period of 30 minutes 
or longer.

Shutdown Zones

    USCG will establish shutdown zones for all pile driving activities. 
The purpose of a shutdown zone is generally to define an area within 
which shutdown of the activity will occur upon sighting of a marine 
mammal (or in anticipation of an animal entering the defined area).
    If a marine mammal is observed entering or within the shutdown 
zones indicated in table 8, pile driving must be delayed or halted. For 
in-water heavy machinery activities other than pile driving, if a 
marine mammal comes within 10 m, work must stop and vessels must reduce 
speed to the minimum level required to maintain steerage and safe 
working conditions. A 10 m shutdown zone will also serve to protect 
marine mammals from physical interactions with project vessels during 
pile driving and other construction activities, such as barge 
positioning or drilling. If an activity is delayed or halted due to the 
presence of a marine mammal, the activity may not commence or resume 
until either the animal has voluntarily exited and been visually 
confirmed beyond the shutdown zone indicated in table 8 or 15 minutes 
have passed without re-detection of the animal. Construction activities 
must be halted upon observation of a species for which incidental take 
is not authorized or a species for which incidental take has been 
authorized but the authorized number of takes has been met entering or 
within the harassment zone.
    All marine mammals will be monitored in the Level B harassment 
zones and throughout the area as far as visual monitoring can take 
place. If a marine mammal enters the Level B harassment zone, in-water 
activities will continue and the animal's presence within the estimated 
harassment zone will be documented.
    USCG will also establish shutdown zones for all marine mammals for 
which take has not been authorized or for which incidental take has 
been authorized but the authorized number of takes has been met. These 
zones are equivalent to the Level B harassment zones for each activity. 
If a marine mammal species for which take is not authorized by this IHA 
enters the shutdown zone, all in-water activities will cease until the 
animal leaves the zone or has not been observed for at least 15 
minutes, and USCG will notify NMFS about the species and precautions 
taken. Pile driving will proceed if the non-IHA species is observed to 
leave the Level B harassment zone or if 15 minutes have passed since 
the last observation.
    If shutdown and/or clearance procedures will result in an imminent 
safety concern, as determined by USCG or its designated officials, the 
in-water activity will be allowed to continue until the safety concern 
has been addressed, and the animal will be continuously monitored.

[[Page 13589]]



                              Table 8--Shutdown Zones and Level B Harassment Zones
----------------------------------------------------------------------------------------------------------------
                                                     Minimum shutdown zone (m)                      Level B
              Activity               ---------------------------------------------------------  harassment zone
                                        VHF cetaceans          Phocid            Otariid              (m)
----------------------------------------------------------------------------------------------------------------
Vibratory Removal...................                 20                 20                 10              1,110
Vibratory Installation..............                 60                 40                 20              1,120
Impact Installation.................                200                100                100                720
----------------------------------------------------------------------------------------------------------------

Protected Species Observers

    The placement of PSOs during all construction activities (described 
in the Monitoring and Reporting section) will ensure that the entire 
shutdown zone is visible. Should environmental conditions deteriorate 
such that the entire shutdown zone will not be visible (e.g., fog, 
heavy rain), pile driving will be delayed until the PSO is confident 
marine mammals within the shutdown zone could be detected.
    The USCG must employ PSOs and establish monitoring locations as 
described in the application and the IHA. PSOs will monitor the full 
shutdown zones and the Level B harassment zones to the extent 
practicable. 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 areas outside the 
shutdown zones and thus prepare for a potential cessation of activity 
should the animal enter the shutdown zone.

Bubble Curtain

    A bubble curtain must be employed during all impact pile 
installation. The bubble curtain must be deployed in a manner 
guaranteed to distribute air bubbles around 100 percent of the piling 
perimeter for the full depth of the water column. The lowest bubble 
ring must be in contact with the mudline for the full circumference of 
the ring. The weights attached to the bottom ring must ensure 100 
percent mudline contact. No parts of the ring or other objects may 
prevent full mudline contact. Air flow to the bubblers must be balanced 
around the circumference of the pile.
    Based on our evaluation of USCG's measures, as well as other 
measures considered by NMFS, NMFS has determined that the mitigation 
measures provide the means effecting the least practicable impact on 
the affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Monitoring and Reporting

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

Visual Monitoring

    Marine mammal monitoring must be conducted in accordance with the 
conditions in this section and the IHA. Marine mammal monitoring during 
pile driving activities must be conducted by PSOs meeting the following 
requirements:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor) and have no other assigned tasks 
during monitoring periods;
     At least one PSO must have prior experience performing the 
duties of a PSO during construction activity pursuant to a NMFS-issued 
incidental take authorization;
     Other PSOs may substitute 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; and,
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator will be designated. The lead 
observer will be required to have prior experience performing the 
duties of a PSO during construction activities pursuant to a NMFS-
issued incidental take authorization.
    PSOs must have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     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, times

[[Page 13590]]

and reason for implementation of mitigation (or why mitigation was not 
implemented when required); and marine mammal behavior; and,
     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.
    USCG must assign a minimum of two PSOs to monitor during pile 
driving. One PSO must be stationed at the pile driving site, and the 
second PSO must be stationed at the best practicable location for 
monitoring the Level A and Level B harassment zones. Possible PSOs 
locations include the staging barges, on shore at the project site, or 
at the entrance to the commercial dock area. All PSOs will have access 
to high-quality binoculars, range finders to monitor distances, and a 
compass to record bearing to animals as well as radios or cells phones 
for maintaining contact with work crews.
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after all in water construction activities. In addition, PSOs 
will record all incidents of marine mammal occurrence, regardless of 
distance from activity, and will document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving 
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.
    USCG shall conduct briefings between construction supervisors and 
crews, PSOs, USCG staff prior to the start of all pile driving 
activities and when new personnel join the work. These briefings must 
explain responsibilities, communication procedures, marine mammal 
monitoring protocol, and operational procedures.

Reporting

    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities, or 60 days prior to a requested date of issuance from any 
future IHAs for projects at the same location, whichever comes first. 
The report will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets.
    Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     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) and the total equipment 
duration for vibratory removal for each pile or total number of strikes 
for each pile (impact driving);
     PSO locations during marine mammal monitoring;
     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;
     Upon observation of a marine mammal, the following 
information: (1) Name of PSO who sighted the animal(s) and PSO location 
and activity at the time of sighting; (2) Time of sighting; (3) 
Identification of the animal(s) (e.g., genus/species, lowest possible 
taxonomic level, or unidentifiable), PSO confidence in identification, 
and the composition of the group if there is a mix of species; (4) 
Distance and bearing of each marine mammal observed relative to the 
pile being driven for each sightings (if pile driving was occurring at 
time of sighting); (5) Estimated number of animals (min/max/best 
estimate); (6) Estimated number of animals by cohort (adults, 
juveniles, neonates, group composition, sex class, etc.); (7) Animal's 
closest point of approach and estimated time spent within the 
harassment zone; (8) Description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
     Number of marine mammals detected within the harassment 
zones and shutdown zones; by species; and,
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensured, 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 USCG must immediately 
cease the specified activities and report the incident to the Office of 
Protected Resources (OPR) ([email protected]), NMFS and 
to the West Coast Regional Stranding Coordinator as soon as feasible. 
If the death or injury was clearly caused by the specified activity, 
USCG must immediately cease the specified activities until NMFS 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 the IHA. The USCG must not resume their activities until notified by 
NMFS. The report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and,
     General circumstances under which the animal was 
discovered.

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

[[Page 13591]]

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, our analysis applies to all species listed in 
table 1 for which take could occur, given that NMFS expects the 
anticipated effects of the planned pile driving and removal on 
different marine mammal stocks to be 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, NMFS has identified species-specific factors to 
inform the analysis.
    Pile driving activities associated with the USCG construction 
project have the potential to disturb or displace marine mammals. 
Specifically, the project activities may result in take, in the form of 
Level A and Level B harassment, from underwater sounds generated from 
pile driving and removal. Potential takes could occur if individuals 
are present in the ensonified zone when these activities are underway.
    The takes by Level B harassment will be due to potential behavioral 
disturbance and TTS. Takes by Level A harassment will be due to 
auditory injury. No serious injury or mortality is expected, even in 
the absence of required mitigation measures, given the nature of the 
activities. The potential for harassment will be further minimized 
through the construction method and the implementation of the planned 
mitigation measures (see Mitigation section). Take by Level A 
harassment is authorized for harbor seals and harbor porpoise to 
account for the possibility that an animal could enter a Level A 
harassment zone prior to detection, and remain within that zone for a 
duration long enough to incur auditory injury before being observed and 
the USCG shutting down pile driving activity. The Level A harassment 
zones identified in table 6 are based upon an animal's exposure to pile 
driving of up to three of the largest steel piles per day. Given the 
short duration to vibratory or impact drive each pile and breaks 
between pile installations (to reset equipment and move piles into 
place), an animal will have to remain within the area estimated to be 
ensonified above the Level A harassment threshold for multiple hours. 
This is highly unlikely given marine mammal movement in the area. The 
number of takes by Level A harassment authorized is very low for both 
marine mammal species. Any take by Level A harassment is expected to 
arise from, at most, a small degree of auditory injury, i.e., minor 
degradation (likely only a few dB) of hearing capabilities within 
regions of hearing that align most completely with the energy produced 
by vibratory and impact pile driving (i.e., the low-frequency region 
below 2 kHz), not severe hearing impairment or impairment within the 
ranges of greatest hearing sensitivity. Animals will 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 auditory injury. Due 
to the small degree anticipated, any auditory injury incurred will not 
be expected to affect the reproductive success or survival of any 
individuals, much less result in adverse impacts on the species or 
stock.
    Additionally, some subset of the individuals that are behaviorally 
harassed could also simultaneously incur some small degree of TTS for a 
short duration of time. However, since the hearing sensitivity of 
individuals that incur TTS is expected to recover completely within 
minutes to hours, it is unlikely that the brief hearing impairment will 
affect the individual's long-term ability to forage and communicate 
with conspecifics, and will therefore not likely impact reproduction or 
survival of any individual marine mammal, let alone adversely affect 
rates of recruitment or survival of the species or stock.
    Behavioral responses of marine mammals to pile driving in the 
Siuslaw River are expected to be mild, short term, and temporary. 
Marine mammals within the Level B harassment zones may not show any 
visual cues they are disturbed by activities or they 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 that pile driving will occur for only a portion of the project's 
duration, any harassment will be temporary. Additionally, many of the 
species present in region will only be present temporarily based on 
seasonal patterns or during transit between other habitats. These 
temporarily present species will be exposed to even smaller periods of 
noise-generating activity, further decreasing the impacts.
    Any impacts on marine mammal prey that will occur during USCG's 
planned activity will have, at most, short-term effects on foraging of 
individual marine mammals, and likely no effect on the populations of 
marine mammals as a whole. Indirect effects on marine mammal prey 
during the construction are expected to be minor, and these effects are 
unlikely to cause substantial effects on marine mammals at the 
individual level, with no expected effect on annual rates of 
recruitment or survival.
    For all species and stocks, take will occur within a limited, 
confined area (adjacent to the project site) of the stock's range, and, 
there are no known biologically important areas (BIAs) near the project 
area that will be impacted by USCG's activities. While harbor seal is 
the species most likely to occur within the immediate project area, the 
nearest haulout is outside of the ensonified areas. There are known 
haulout sites for harbor seals near the project area including across 
the river and upriver from the action area, the closest being 400 m 
from the project area. Although, the most recent survey taken of this 
area was in 2014. There are no other haulouts in the immediate project 
vicinity; the next closest haulout is 129 km away.
    In addition, it is unlikely that minor noise effects in a small, 
localized area of habitat will have any effect on the reproduction or 
survival of any individuals, much less the stocks' annual rates of 
recruitment or survival. In combination, we believe that these factors, 
as well as the available body of evidence from other similar 
activities, demonstrate that the potential effects of the specified 
activities would have only minor, short-term effects on individuals. 
The specified activities are not expected to impact rates of 
recruitment or survival and would therefore not result in population-
level impacts.
    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:
     No serious injury or mortality is anticipated or 
authorized;
     Take by Level A harassment is authorized for harbor seal 
and harbor porpoise only and will be very small amounts and of a low 
degree;
     For all species and stocks, the Siuslaw River is a very 
small and peripheral part of their range;
     The intensity of anticipated takes by Level B harassment 
is relatively low for all stocks. Level B harassment will be primarily 
in the form of behavioral disturbance, resulting in avoidance of the 
project areas around where impact or vibratory pile driving is 
occurring, with some low-level TTS that may limit the detection of 
acoustic cues for

[[Page 13592]]

relatively brief amounts of time in relatively confined footprints of 
the activities;
     Effects on species that serve as prey for marine mammals 
from the activities are expected to be short-term and, therefore, any 
associated impacts on marine mammal feeding are not expected to result 
in significant or long-term consequences for individuals, or to accrue 
to adverse impacts on their populations;
     The project area does not overlap any areas of known 
important habitat for marine mammals;
     The ensonified areas are very small relative to the 
overall habitat ranges of all species and stocks; and,
     The lack of anticipated significant or long-term negative 
effects to marine mammal habitat.
    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 planned 
activities 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. For all species, the 
take is below one third of the population for all marine mammal stocks 
(table 7).
    Based on the analysis contained herein of the planned 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.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks will not 
have an unmitigable adverse impact on the availability of such species 
or stocks for taking for subsistence purposes.

Endangered Species Act

    Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.) 
requires that each Federal agency insure that any action it authorizes, 
funds, or carries out is not likely to jeopardize the continued 
existence of any endangered or threatened species or result in the 
destruction or adverse modification of designated critical habitat. To 
ensure ESA compliance for the issuance of IHAs, NMFS consults 
internally whenever we authorize take for endangered or threatened 
species.
    No incidental take of ESA-listed species is authorized or expected 
to result from this activity. Therefore, NMFS has determined that 
formal consultation under section 7 of the ESA is not required for this 
action.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment.
    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 the IHA qualifies to be categorically excluded from further 
NEPA review.

Authorization

    NMFS has issued an IHA to the USCG for the potential harassment of 
small numbers of four marine mammal species incidental to the Station 
Siuslaw River Construction Project in Florence, Oregon, that includes 
the previously explained mitigation, monitoring and reporting 
requirements.

    Dated: March 19, 2025.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2025-04995 Filed 3-24-25; 8:45 am]
BILLING CODE 3510-22-P