[Federal Register Volume 87, Number 159 (Thursday, August 18, 2022)]
[Notices]
[Pages 50836-50849]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-17775]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC232]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Tillamook South Jetty Repairs in 
Tillamook Bay, Oregon

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

ACTION: Notice; issuance of incidental harassment authorizations.

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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 two incidental harassment authorizations (IHAs) to 
the U.S. Army Corps of Engineers (USACE)--Portland District (Corps) to 
incidentally harass, by Level A and Level B harassment only, marine 
mammals during construction activities associated with a Tillamook 
South Jetty Repairs in Tillamook Bay, Oregon.

DATES: The Year 1 IHA is effective from November 1, 2022 through 
October 31, 2023. The Year 2 IHA is effective from November 1, 2024 
through October 31, 2024.

FOR FURTHER INFORMATION CONTACT: Reny Tyson Moore, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems 
accessing these documents, please call the contact listed above.

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 mitigation, 
monitoring and reporting of the takings are set forth.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

Summary of Request

    On February 11, 2022, NMFS received a request from the Corps for 
two one-year IHAs to take marine mammals incidental to repairs of the 
Tillamook South Jetty in Tillamook Bay, Oregon. The application was 
deemed adequate and complete on May 23, 2022. The Corps' request is for 
take of five species of marine mammals by Level B harassment and, for a 
subset of these species (i.e., harbor seals (Phoca vitulina richardii), 
northern elephant seals (Mirounga angustriostris), and harbor porpoises 
(Phocoena phocoena)), take by Level A harassment. Neither the Corps nor 
NMFS expect serious injury or mortality to result from this activity 
and, therefore, IHAs are appropriate.

Description of Activity

    The Corps constructed, and continues to maintain, two jetties at 
the entrance of Tillamook Bay, Oregon to provide reliable navigation 
into and out of the bay. A Major Maintenance Report (MMR) was completed 
in 2003 to evaluate wave damage to the jetties and provide design for 
necessary repairs. Some repairs to the North Jetty were completed in 
2010, and further repairs to the North Jetty root and trunk began in 
January 2022. The Tillamook South Jetty Repairs Project (i.e., the 
``Corps' activities'') will complete critical repairs to the South 
Jetty, as described in the MMR, with a focus on rebuilding the South 
Jetty head. Work will consist of repairs to the existing structures 
within the original jetty footprints (i.e., trunk repairs and the 
construction of a 100-foot cap to repair the South Jetty Head), with 
options to facilitate land- and water-based stone transport, storage,

[[Page 50837]]

and placement operations. A temporary material offload facility (MOF), 
which will be approximately 15 meters (m) (50 feet (ft)) by 30 m (100 
ft), will be constructed at Kincheloe Point to transfer jetty rock from 
barges to shore at the South Jetty.
    The two IHAs requested by the Corps will be associated with the 
construction (Year 1 IHA) and removal (Year 2 IHA) of the temporary 
MOF. Construction of the MOF will involve vibratory (preferred) and/or 
impact pile driving of up to 10 12-inch H piles, 24 24-inch timber or 
steel pipe piles, and 250 24-inch steel sheets (type NZ, AZ, PZ, or 
SCZ) (Table 1), and is anticipated to take 20 to 23 days and to occur 
between November 1, 2022 and February 15, 2023 or between July 1, 2023 
and August 31, 2023 (Year 1). Removal of the MOF will involve vibratory 
extraction of all installed piles and sheets and is anticipated to take 
13 days and is anticipated to occur between November 1, 2024 and 
February 15, 2025 or between July 1, 2025 and August 31, 2025 (Year 2). 
The Corps' work windows are between November and February and between 
July and August each year to adhere to terms and conditions outlined in 
the U.S. Fish and Wildlife Service (USFWS) Biological Opinion (BiOp) to 
minimize potential take of the Western snowy plover (WSP), currently 
listed as threatened under the Endangered Species Act (ESA). Sounds 
resulting from pile installation and removal from the Corps' may result 
in the incidental take of marine mammals by Level A and Level B 
harassment. The Year 1 IHA is effective from November 1, 2022 to 
October 31, 2023; the Year 2 IHA is effective from November 1, 2024 to 
October 31, 2025.

                                   Table 1--Summary of Pile Details and Estimated Effort Required for the Construction and Deconstruction of the Temporary MOF
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Vibratory                        Potential         Production rate (piles/day)          Range of installation      Range of
                                                  Number of     installation        Vibratory        impact   -----------------------------------------   days anticipated \1\       vibratory
          Pile type                  Size          sheets/      duration per    removal duration  strikes per                                          --------------------------  removal days
                                                    piles        pile/sheet      per pile/sheet     pile, if   Installation  Installation    Removal     Vibratory    Vibratory     anticipated
                                                                  (minutes)         (minutes)        needed     (vibratory)    (impact)    (vibratory)      only      and impact        \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
AZ Steel Sheet \2\...........  24-inch.........          250  10..............  3...............  ...........            25  ............           50        10-12        10-12             5-7
Timber or Steel Pile.........  24-inch.........           24  15..............  5...............          533             8             4           12          3-6          6-9             2-4
H-Pile.......................  12-inch.........           10  10..............  3...............  ...........            10  ............           10          1-2          1-2             1-2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                 Project Totals                          284  49.83 hours.....  16.17 hours.....  ...........  ............  ............  ...........        14-20        17-23            8-13
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The minimum days of installation and removal are based on the expected production rates. The maximum days of installation and removal are estimated assuming built in contingency days,
  which have been added into the construction schedule, are needed.
\2\ Or comparable.

    A detailed description of the planned construction project is 
provided in the Federal Register notice for the proposed IHA (87 FR 
38116; June 27, 2022). 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
    Mitigation, monitoring, and reporting measures are described in 
detail later in this document (please see Mitigation and Monitoring and 
Reporting).

Comments and Responses

    A notice of NMFS' proposal to issue two IHAs to the Corps was 
published in the Federal Register on June 27, 2022 (87 FR 38116). That 
notice described, in detail, The Corps' 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 authorizations, and any other aspect of the notice of proposed 
IHAs, and requested that interested persons submit relevant 
information, suggestions, and comments. This proposed notice was 
available for a 30-day public comment period.
    NMFS received no public comments.

Changes From the Proposed IHA to Final IHA

    No substantive changes from the proposed IHAs to the final IHAs 
have been made that affect our analysis. Per the Corps' request the 
phrase ``during pile driving'' has been added to item 5(a) in the Year 
2 IHA to clarify when monitoring by Protected Species Observers (PSOs) 
is required. In addition, typographical errors were identified in Table 
4 in the Proposed IHA which have been corrected in the Final IHA (now 
Table 3). Specifically, the weighted cumulative sound exposure 
(LE,p) impulsive PTS onset thresholds for low frequency 
cetaceans, mid-frequency cetaceans, and phocid pinnipeds were incorrect 
and have been corrected. No other changes have been made from the 
proposed IHAs to the final IHAs.

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, incorporated here by reference, instead of 
reprinting the information. Additional information regarding population 
trends and threats may be found in NMFS' Stock Assessment Reports 
(SARs; 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 2 lists all species or stocks for which take is expected and 
authorized for these activities, and summarizes information related to 
the population or stock, including regulatory status under the MMPA and 
ESA and potential biological removal (PBR), where known. PBR is defined 
by the MMPA as the maximum number of animals, not including natural 
mortalities, that may be removed from a marine mammal stock while 
allowing that stock to reach or maintain its optimum sustainable 
population (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 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

[[Page 50838]]

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 (e.g., Carretta et al. 2021) or 
Alaska SARs (e.g., Muto et al. 2020). All values presented in Table 2 
are the most recent available at the time of publication and are 
available in the 2020 SARs (Carretta et al. 2021, Muto et al., 2020) 
and draft 2021 SARs (available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                                              Table 2--Species Likely Impacted by the Specified Activities
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                                                                                                            Stock abundance Nbest,
                                                                                         ESA/MMPA status;   (CV, Nmin, most recent             Annual M/
             Common name                  Scientific name             MMPA stock          strategic (Y/N)    abundance survey) \2\     PBR       SI \3\
                                                                                                \1\
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                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocoenidae (porpoises):
    Harbor Porpoise.................  Phocoena phocoena......  Northern OR/WA Coast...  -,-, N              21,487 (0.44; 15,123;         151      >=3.0
                                                                                                             2011).
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                                                         Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
 sea lions):
    California sea lion.............  Zalophus californianus.  U.S....................  -,-, N              257,606 (N/A.;             14,011       >320
                                                                                                             233,515; 2014).
    Steller sea lion................  Eumetopias jubatus.....  Eastern................  -,-, N              43,201 (N/A; 43,201;        2,592        112
                                                                                                             2017).
Family Phocidae (earless seals):
Harbor seal.........................  Phoca vitulina           OR/CA Coastal..........  -, N                24,732 (0.12; N/A;            UND       10.6
                                       richardii.                                                            1999).
Northern elephant seal..............  Mirounga angustirostris  California Breeding....  -,-, N              187,386 (N/A; 85,369;       5,122        5.3
                                                                                                             2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.

    As indicated above, all 5 species (with 5 managed stocks) in Table 
2 temporally and spatially co-occur with the activity to the degree 
that take is reasonably likely to occur, and we have authorized it. All 
species (26 marine mammal species and 27 marine mammal stocks) that 
could potentially occur in the action areas are included in Table 3-3 
of the Corps' application. The majority of the species listed in the 
Corps' table are unlikely to occur in the project vicinity. For 
example, numerous cetaceans (i.e., sei whale, Balaenoptera borealis 
borealis; fin whale, Balaenoptera physalus physalus; Risso's dolphin, 
Grampus griseus; common bottlenose dolphin, Tursiops truncatus 
truncatus; striped dolphin, Stenella coeruleoalba; common dolphin, 
Delphinus delphis; short-finned pilot whale, Globicephala 
macrorhynchus; Baird's beaked whale, Berardius bairdii; Mesoplodont 
beaked whale, Mesoplodon spp.; Cuvier's beaked whale, Ziphius 
cavirostris; pygmy sperm whale, Kogia breviceps; dwarf sperm whale, 
Kogia sima; sperm whale, Physeter macrocephalus) are only encountered 
at the continental slope (>20 kilometers (km)/12 miles (mi) offshore) 
or in deeper waters offshore and will not be affected by construction 
activities. Other species may occur closer nearshore but are rare or 
infrequent seasonal inhabitants off the Oregon coast (i.e., minke 
whale, Balaenoptera acutorostrata scammoni; Pacific white-sided 
dolphin, Lagenorhynchus obliquidens; Northern right-whale dolphin, 
Lissodelphis borealis; killer whale, Orcinus orca (``Eastern North 
Pacific Southern Resident Stock''); Dall's porpoise, Phocoenoides dalli 
dalli). Given these considerations, the temporary duration of potential 
pile driving, and noise isopleths that will not extend beyond the bay 
entrance (please see Estimated Take), there is no reasonable 
expectation for the Corps' activities to affect the above species and 
they will not be addressed further.
    While ten marine mammal species could occur in the vicinity of the 
Corps' activities (i.e., harbor seals; Northern elephant seal; Steller 
sea lion; California sea lion; humpback whales, Megaptera novaeangliae; 
fin whales, Balaenoptera physalus physalus; gray whales, Eschrichtius 
robustus; blue whales, Balaenoptera musculus musculus; killer whales, 
Orcinus orca; and harbor porpoises), Tillamook Bay is relatively 
shallow and noise resulting from the construction/deconstruction of the 
MOF will be limited to the interior waters of the bay and will not 
extend to coastal waters. Larger whales (e.g., humpback whales, fin 
whales, gray whales, blue whales, killer whales) may transit the waters 
near the coastline but are unlikely inhabitants of Tillamook Bay 
itself. In reviewing OBIS-SEAMAP (2022) and records for all marine 
mammals recorded within a 16 km (10 mi) radius of Tillamook Bay, only 
humpback whales, gray whales, harbor porpoises, California sea lions, 
Steller sea lions, and harbor seals were commonly reported. Killer 
whales have only been seen on rare occasions (TinyFishTV, 2014; 
rempeetube, 2016; Corey.c, 2017), and Dall's porpoise (and northern 
right whale dolphins have been reported a bit further offshore (Halpin 
et al., 2009; OBIS-SEAMAP, 2022). Gray whales and humpback whales have 
been observed in the vicinity of Tillamook Bay, however, they are 
highly unlikely to enter the relatively shallow waters of Tillamook Bay 
and be subject to pile driving noise

[[Page 50839]]

disturbance. Given these considerations, take of these species (i.e., 
humpback whales, fin whales, gray whales, blue whales, killer whales) 
is not expected to occur, and they are not discussed further beyond the 
explanation provided here.
    A detailed description of the species likely to be affected by the 
Corps' 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, was 
provided in the Federal Register notice for the proposed IHA (87 FR 
33116; June 27, 2022). 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.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from the Corps' construction 
activities have the potential to result in behavioral harassment of 
marine mammals in the vicinity of the survey area. The notice of 
proposed IHAs IHA (87 FR 33116; June 27, 2022) included a discussion of 
the effects of anthropogenic noise on marine mammals and the potential 
effects of underwater noise from the Corps' construction activities on 
marine mammals and their habitat. That information and analysis is 
incorporated by reference into this final IHA determination and is not 
repeated here; please refer to the notice of proposed IHAs (87 FR 
33116; June 27, 2022).

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized through these IHAs, which will inform both NMFS' 
consideration of ``small numbers'' and the negligible impact 
determinations.
    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 and removal) 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 high frequency cetaceans and/or 
phocids because predicted auditory injury zones are larger than for 
otariids. Auditory injury is unlikely to occur for 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 or 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 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-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.
    The Corps' activity includes the use of continuous (vibratory pile 
driving/removal) 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 Corps' 
activity includes the use of impulsive (impact pile driving) and non-
impulsive (vibratory pile driving/removal) 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: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

[[Page 50840]]



                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                         PTS onset thresholds\*\ (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lp,0-pk,flat: 219   Cell 2: LE,p, LF,24h: 199 dB.
                                          dB; LE,p, LF,24h: 183 dB..
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lp,0-pk,flat: 230   Cell 4: LE,p, MF,24h: 198 dB.
                                          dB; LE,p, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lp,0-pk,flat: 202   Cell 6: LE,p, HF,24h: 173 dB.
                                          dB; LE,p,HF,24h: 155 dB.
Phocid Pinnipeds (PW)..................  Cell 7: Lp,0-pk.flat: 218   Cell 8: LE,p,PW,24h: 201 dB.
(Underwater)...........................   dB; LE,p,PW,24h: 185 dB.
Otariid Pinnipeds (OW).................  Cell 9: Lp,0-pk,flat: 232   Cell 10: LE,p,OW,24h: 219 dB
(Underwater)...........................   dB; LE,p,OW,24h: 203 dB..
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 are recommended for consideration.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
  exposure level (LE,p) has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
  is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
  hearing range of marine mammals (i.e., 7 Hz to 160 kHz). 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 weighted
  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 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 Corp's activities. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., impact pile driving, vibratory 
pile driving, and vibratory pile removal).
    Sound Source Levels of Activities--The intensity of pile driving 
sounds is greatly influenced by factors such as the type of piles, 
hammers, and the physical environment in which the activity takes 
place. In order to calculate distances to the Level A harassment and 
Level B harassment sound thresholds for the methods and piles being 
used in this project, NMFS used empirical data from sound source 
verification (SSV) studies reported in Navy (2015) and CALTRANS (2020), 
to develop source levels for the various pile types, sizes and methods 
(Table 4). These proxies were chosen as they were obtained from SSV 
studies on piles of comparable types and sizes and/or in comparable 
environments (e.g., they had comparable water depths). Note that these 
source levels represents the SPL referenced at a distance of 10 m from 
the source. It is conservatively assumed that the Corps will use steel 
instead of timber for the 24-inch pipe piles as the estimated proxy 
values for steel are louder than timber (e.g., Greenbusch Group, 2018; 
84 FR 61026, November 12, 2019). It is also conservatively assumed that 
vibratory removal will produce comparable levels of in-water noise as 
vibratory installation.

   Table 4--Estimates of Underwater Sound Levels Generated During Vibratory and Impact Pile Installation, and
                                             Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
                                                  Source level    Source level    Source Level
     Pile driving method       Pile description     (dB Peak)       (dB RMS)        (dB SEL)        Reference
----------------------------------------------------------------------------------------------------------------
Impact (attenuated \1\)......  24-inch steel                198             184             173  CALTRANS
                                pipe pile.                                                        (2020).
Vibratory (installation and    24-inch steel                177             161  ..............  Navy (2015).
 removal; unattenuated).        pipe pile.
                               24-inch AZ steel  ..............             163             163  CALTRANS
                                sheets.                                                           (2020).
                               12-inch steel H-             165             150             147  CALTRANS
                                piles.                                                            (2020).
----------------------------------------------------------------------------------------------------------------
\1\ The estimated SPLs for 24-inch steel pipes assume a 5 dB reduction resulting from the use of a confined
  bubble curtain system.

    Level B Harassment Zones--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 * log10 (R1/R2),

Where:
B = transmission loss coefficient (assumed to be 15)
R1 = the distance of the modeled SPL from the driven pile, and
R2 = 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. The recommended TL coefficient for most nearshore 
environments is the practical spreading value of 15. This value results 
in an expected propagation environment that will lie between spherical 
and cylindrical spreading loss conditions, which is the most 
appropriate assumption for the Corps' construction activities in the 
absence of specific modelling. All Level B harassment isopleths are 
reported in Table 6

[[Page 50841]]

considering RMS SSLs for impact and vibratory pile driving, 
respectively.
    Level A Harassment Zones--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 vibratory and impact 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, and the resulting estimated isopleths, 
are reported in Table 5.

                                                          Table 5--NMFS User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                  Impact pile                                             Vibratory pile driving
                                    driving     --------------------------------------------------------------------------------------------------------
                              ------------------                     Installation                                           Removal
                                 Installation   --------------------------------------------------------------------------------------------------------
                              ------------------
                                 24-inch steel     24-inch steel   24-inch AZ steel  12-inch steel  H-  24-inch steel      24-inch AZ     12-inch steel
                                   pipe pile         pipe pile          sheets             piles          pipe pile       steel sheets       H-piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used.........  E.1) Impact pile  A.1) Non-Impul,   A.1) Non-Impul,   A.1) Non-Impul,   A.1) Non-Impul,  A.1) Non-Impul,  A.1) Non-Impul,
                                driving.          Stat, Cont.       Stat, Cont.       Stat, Cont.       Stat, Cont.      Stat, Cont.      Stat, Cont
Source Level (SPL)...........  173 dB SEL......  161 dB RMS......  163 dB RMS......  150 dB RMS......  161 dB RMS.....  163 dB RMS.....  150 dB RMS
Transmission Loss Coefficient  15..............  15..............  15..............  15..............  15.............  15.............  15
Weighting Factor Adjustment    2...............  2.5.............  2.5.............  2.5.............  2.5............  2.5............  2.5
 (kHz).
Number of strikes per pile...  533.............  ................  ................  ................  ...............  ...............  ...............
Time to install/remove single  ................  15..............  10..............  10..............  5..............  3..............  3
 pile (minutes).
Piles per day................  4...............  8...............  25..............  10..............  12.............  50.............  10
--------------------------------------------------------------------------------------------------------------------------------------------------------


           Table 6--Distances to Level A Harassment, by Hearing Group, and Level B Harassment Thresholds per Pile Type and Pile Driving Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    Level A harassment distance      Level A      Level B      Level B
                                                                                                (m)                 harassment   harassment   harassment
                                                                       Piles per ---------------------------------    areas       distance      areas
                Activity                        Pile description          day                                      (km\2\) for    (m) all    (km\2\) for
                                                                                      HF         PW         OW     all hearing    hearing    all hearing
                                                                                                                      groups     groups \1\   groups \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation (attenuated) \2\....  24-inch steel pipe pile....          4      424.5      190.7       13.8        < 0.5          399         0.39
Vibratory Installation..................  24-inch steel pipe pile....          8       16.0        6.6        0.5        < 0.1        5,412        20.14
                                          24-inch AZ steel sheets....         14       35.5       14.6        1.0        < 0.1        7,357        27.01
                                          12-inch steel H-piles......         10        2.6        1.1        0.1        < 0.1        1,000         1.84
Vibratory Removal.......................  24-inch steel pipe pile....         12       10.1        4.2        0.3        < 0.1        5,412        20.14
                                          24-inch AZ steel sheets....         50       25.3       10.4        0.7        < 0.1        7,357        27.01
                                          12-inch steel H-piles......         10        1.2        0.5        0.0        < 0.1        1,000         1.84
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Harassment areas have been truncated where appropriate to account for land masses.
\2\ Distances to Level A harassment, by hearing group, for impact pile driving were calculated based on SEL source levels as they resulted in larger,
  thus more conservative, isopleths for calculating PTS onset than Peak source levels.

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information, that 
inform the take calculations. We also describe how the information 
provided above is synthesized to produce a quantitative estimate of the 
take that is reasonably likely to occur and which is authorized.
    In most cases, recent marine mammal counts, density estimates, or 
abundance estimates were not available for Tillamook Bay. Thus, 
information regarding marine mammal occurrence from proximal data 
obtained from nearshore sightings and haul-out sites (e.g., Three Arch 
Rock) is used to approximate local abundance in Tillamook Bay. When 
proximal count estimates were available (i.e., for harbor seals, 
Steller sea lions, and California sea lions), the Corps derived density 
estimates with an assumption that surveys accounted for animals present 
in the entirety of Tillamook Bay, an area roughly 37 km\2\ (Oregon 
Coastal Atlas, 2022). The Corps multiplied marine mammal densities by 
isopleth areas to estimate potential take associated with pile driving. 
Given that marine mammal densities are likely not uniform in Tillamook 
Bay, NMFS instead estimates take associated with pile driving for these 
and the other marine mammal species assuming maximum daily occurrence 
rates (based on the abovementioned nearby proximal count estimates) 
multiplied by the total number of action days estimated per activity. 
There may be 20 (vibratory pile driving only) to 23 (vibratory and 
impact pile driving) total days of noise exposure from pile driving 
during the Corps' activities in Year 1 and 13 (vibratory removal only) 
total days of noise exposure from pile driving during the Corps' 
activities in Year 2. Takes for Year one for all species except harbor 
porpoises (see below) are estimated assuming that both vibratory and 
impact pile driving will be necessary and thus the maximum number of 
days of action

[[Page 50842]]

days are required (i.e., 23 days). Takes for Year two assume that 13 
total action days are required. A summary of authorized take is 
available in Tables 7 and 8.

Harbor Porpoises

    There were multiple occurrences of 1-2 harbor porpoises detected in 
the coastal waters just north of the Tillamook Bay entrance during June 
and July of 1990 (Halpin et al., 2009; Ford et al., 2013). More 
recently, aerial surveys have detected single animals near the 
Tillamook Bay entrance in October 2011 and September 2012 (Adams et 
al., 2014). Although there were no recorded harbor porpoise 
observations within Tillamook Bay itself, the species is somewhat 
cryptic and there is potentially low detection during aerial surveys. 
Thus, NMFS estimates the daily harbor porpoise abundance within 
Tillamook Bay to be 1 individual.
    During Year 1, if impact pile driving is necessary for driving 
steel piles, the Level A harassment distance for this activity for 
harbor porpoises is larger than the Level B harassment distance (Table 
6) and the shutdown zone (see Table 9 in the Mitigation section). 
Therefore, the Corps proposed that all harbor porpoises in Tillamook 
Bay on days when impact pile driving occurs will be taken by Level A 
harassment. NMFS concurs with this estimate and authorizes 9 instances 
of take by Level A harassment for harbor porpoises in Year 1 during 
construction of the MOF (1 harbor porpoise per day x 9 days of impact 
pile driving = 9 takes by Level A harassment).
    During Year 1, if vibratory and impact pile driving is required, 
the Corps estimated that there could be 14 takes of harbor porpoises by 
Level B harassment (1 harbor porpoise per day x 12 days vibratory 
installing steel sheets = 12 takes by Level B harassment, and 1 harbor 
porpoise per day x 2 days vibratory installing H piles = 2 takes by 
Level B harassment, for a total of 14 takes by Level B harassment; 
Table 1). If only vibratory pile driving is required, the Corps 
estimated that 20 harbor porpoises may be taken by Level B harassment 
(1 harbor porpoise per day x 20 total action days; Table 1). Therefore, 
to be conservative, NMFS authorizes 20 instances of take by Level B 
harassment for harbor porpoises (the maximum estimate of animals that 
may be taken by Level B harassment based on the two likely scenarios) 
in Year 1 during construction of the MOF.
    During Year 2, the Corps requested and NMFS authorizes 13 instances 
of take by Level B harassment for harbor porpoises during vibratory 
removal of the MOF (1 harbor porpoise per day x 13 total action days; 
Table 1). No Level A harassment is anticipated to occur or is 
authorized. Considering the small Level A harassment zones (Table 6) in 
comparison to the required shutdown zones (see Table 9 in the 
Mitigation section) it is unlikely that a harbor porpoise will enter 
and remain within the area between the Level A harassment zone and the 
shutdown zone for a duration long enough to be taken by Level A 
harassment.

California Sea Lions

    The estimate for daily California sea lion abundance (n = 11) is 
based on coastal surveys conducted between 2002 and 2005 (Scordino, 
2006). While pile driving will occur in winter or summer, the maximum 
number of animals detected during any month (i.e., 11 sea lions in 
April) at the Three Arch Rock haul out site, located approximately 23 
km (14 mi) from the site of the MOF, was used to estimate daily 
occurrence by the Corps. Given the distance of this haul out site from 
the Corps' activities, the fact that pile driving is not expected to 
occur in April due to timing constrictions, and the low likelihood that 
all animals present at the Three Arch Rock will leave and enter 
Tillamook Bay on a single day; the Corps' estimated that approximately 
half of the individuals present at Three Arch Rock (6 California sea 
lions) could potentially enter Tillamook Bay during pile driving and be 
subject to acoustic harassment. NMFS concurs and estimates, based on 
the best available science, the daily California sea lion abundance 
within Tillamook Bay to be 6 individuals.
    During Year 1, NMFS authorizes 138 instances of take by Level B 
harassment for California sea lions during the construction of the MOF 
(6 California sea lions per day x 23 total action days required for 
impact and vibratory pile driving; Table 1). During Year 2, NMFS 
authorizes 78 instances of take by Level B harassment for California 
sea lions during vibratory removal of the MOF (6 California sea lions 
per day x 13 total action days; Table 1). Under either scenario, Level 
A harassment is not anticipated or authorized for Year 1 or Year 2. 
Considering the small Level A harassment zones (Table 6) in comparison 
to the required shutdown zones (see Table 9 in the Mitigation section) 
it is unlikely that a California sea lion will enter and remain within 
the area between the Level A harassment zone and the shutdown zone for 
a duration long enough to be taken by Level A harassment.

Steller Sea Lions

    The Corps and NMFS are unaware of any recent data regarding Steller 
sea lion abundance near Tillamook Bay. Therefore, seasonal Steller sea 
lion abundance was estimated based on the maximum number of animals 
detected (n = 38 for between November and February, and n = 58 between 
July and August) at the Three Arch Rock haul out site during coastal 
surveys between 2002 and 2005 (Scordino, 2006). Given that this haul 
out site is roughly 23 km (14 mi) away from the MOF, the Corps 
conservatively estimated that half of the individuals present at Three 
Arch Rock (19 Steller sea lions between November and February, and 29 
Steller sea lions between July and August) could potentially disperse 
throughout Tillamook Bay during pile driving and be subject to 
harassment from the Corps' activities. For the purposes of our take 
estimation, NMFS conservatively assumes that the daily Steller sea lion 
abundance in Tillamook Bay is equivalent to the largest seasonal 
abundance that the Corps estimated will be present (i.e., we assume 
that 29 individual Steller sea lions will be present each day in 
Tillamook Bay).
    During Year 1, NMFS authorizes 667 instances of take by Level B 
harassment for Steller sea lions during the construction of the MOF (29 
Steller sea lions per day x 23 total action days required for impact 
and vibratory pile driving; Table 1). During Year 2, NMFS authorizes 
377 instances of take by Level B harassment for Steller sea lions 
during vibratory removal of the MOF (6 Steller sea lions per day x 13 
total action days; Table 1). Under either scenario, Level A harassment 
is not anticipated or authorized for Year 1 or Year 2. The Level A 
harassment zones (Table 6) are smaller than the required shutdown zones 
(see Table 9 in the Mitigation section), therefore it is unlikely that 
a Steller sea lion will enter and remain within the area between the 
Level A harassment zone and the shutdown zone for a duration long 
enough to be taken by Level A harassment.

Harbor Seals

    The latest (May 2014) pinniped aerial surveys conducted by the 
Oregon Department of Fish and Wildlife (ODFW, 2022) estimated 220 
harbor seals (pups and non-pups combined) within Tillamook Bay (B.E. 
Wright, personal communication, February 12, 2021). After applying the 
Huber et al. (2001) correction factor of 1.53, used to account for 
likely imperfect detection during surveys, the adjusted number of 
harbor seals that may have been present

[[Page 50843]]

Tillamook Bay during the 2014 surveys is approximately 337 individuals. 
However, that estimate likely overestimates the number of harbor seals 
present in the non-pupping season. Therefore, the Corps used 
calculations from monthly surveys of Tillamook Bay haul out sites 
between 1978 and 1981 carried out by Brown and Mate (1983) to estimate 
the average proportion of animals present during the Corps' Nov-Feb and 
Jul-Aug construction windows (relative to counts observed in May). 
Accounting for these proportions (0.67 and 1.2, respectively), the 
Corps estimated that the 337 harbor seals likely present in May 2014 
will have equated to an average abundance of 226 harbor seals between 
November and February and 404 harbor seals between July and August. For 
the purposes of our take estimation, NMFS conservatively assumes that 
the daily harbor seal abundance in Tillamook Bay is equivalent to the 
largest seasonal abundance that the Corps estimated will be present 
(i.e., we assume that 404 individual harbor seals will be present each 
day in Tillamook Bay).
    During Year 1, NMFS estimates that 9,292 total instances of take 
for harbor seals will occur during the construction of the MOF (404 
harbor seals per day x 23 total action days required for impact and 
vibratory pile driving; Table 1). NMFS estimates that 3,636 of these 
instances of take will be attributed to impact pile driving (404 harbor 
seals per day x 9 days impact pile driving) and the remaining 5,656 
instances of take will be attributed to vibratory pile driving (404 
harbor seals per day x 14 days vibratory pile driving). During impact 
pile driving, while a 100 m shutdown zone will be implemented for 
harbor seals (see Table 9 in the Mitigation section), an area of 
approximately 0.07 km\2\ will still be ensonified above the Level A 
harassment threshold for phocids (Table 6). Given this remaining Level 
A harassment area for phocids is 17.95 percent of the Level B 
harassment area (0.39 km\2\), NMFS authorizes 653 (17.95 percent) of 
the total instances of take attributed to impact pile driving (i.e., 
17.95 percent of 3,636 instances of take), as instances of take by 
Level A harassment. NMFS authorizes the remaining 8,639 instances of 
take by Level B harassment.
    During Year 2, NMFS authorizes 5,252 instances of take by Level B 
harassment for harbor seals during vibratory removal of the MOF (404 
harbor seals per day x 13 total action days; Table 1). No take by Level 
A harassment is anticipated to occur or is authorized. The Level A 
harassment zones (Table 6) are smaller than the required shutdown zones 
(see the Mitigation section), therefore it is unlikely that a harbor 
seal will enter and remain within the area between the Level A 
harassment zone and the shutdown zone for a duration long enough to be 
taken by Level A harassment during MOF deconstruction.

Northern Elephant Seal

    There were no recorded sightings of elephant seals within 16 km (10 
mi) of Tillamook Bay within the OBIS-SEAMAP database (Halpin et al., 
2009; OBIS-SEAMAP, 2022) nor were any animals detected at the closest 
haul out site (i.e., Three Arch Rock) during pinniped surveys between 
2002 and 2005 (Scordino, 2006). In fact, the closest haul out site with 
Northern elephant seal observations during surveys was Cape Arago 
(Scordino 2006), roughly 6 km (4 mi) south of Coos Bay and 256 km (159 
mi) south of Tillamook Bay. Given the low likelihood of occurrence 
within the project vicinity and the lack of reported sightings within 
the bay (Halpin et al., 2009; OBIS-SEAMAP, 2022), the Corps 
conservatively estimated, and NMFS assumes, elephant seal abundance 
within Tillamook Bay at 1 individual every other day.
    During Year 1, the Corps estimated that 12 northern elephant seals 
may be taken during the construction of the MOF (1 elephant seal every 
other day x 23 total action days; Table 1). If impact pile driving is 
necessary for driving steel piles, the Corps estimated that the total 
take during the 9 days of impact pile driving will be 5 individuals (1 
elephant seal every other day x 9 total action days; Table 1). While a 
100 m shutdown zone will be implemented for northern elephant seals 
during impact pile driving (see Table 9 in the Mitigation section), an 
area of approximately 0.07 km\2\ will still be ensonified above the 
Level A harassment threshold for phocids during this activity (Table 
6). Given this remaining Level A harassment area for phocids (0.07 
km\2\) is 17.95 percent of the Level B harassment area (0.39 km\2\), 
NMFS authorizes 17.95 percent, or 1, instance of take by Level A 
harassment for northern elephant seals during impact pile driving 
(17.95 percent of the 12 total instances of take). The remaining 11 
instances of take are authorized to be take by Level B harassment.
    During Year 2, the Corps requested and NMFS authorizes 7 instances 
of Level B harassment take for northern elephant seals during vibratory 
removal of the MOF (1 elephant seal every other day x 13 total action 
days; Table 1). Level A harassment is not anticipated or authorized. 
The Level A harassment zones (Table 6) are smaller than the required 
shutdown zones (see Table 9 in the Mitigation section), therefore it is 
unlikely that a northern elephant seal will enter and remain within the 
area between the Level A harassment zone and the shutdown zone for a 
duration long enough to be taken by Level A harassment during 
deconstruction of the MOF.

                                 Table 7--Authorized Amount of Taking in Year 1
----------------------------------------------------------------------------------------------------------------
                                                                                                   Instances of
                                                                                                     take as a
            Species                   Stock           Level A         Level B          Total      percentage  of
                                                                                                       stock
                                                                                                     abundance
----------------------------------------------------------------------------------------------------------------
Harbor porpoise...............  Northern OR/WA                 9              20              29            0.14
                                 Coast.
California sea lion...........  U.S.............               0             138             138            0.05
Steller sea lion..............  Eastern.........               0             667             667            1.54
Harbor seal...................  OR/CA Coastal...             653           8,639           9,292           37.57
Northern elephant seal........  California                     1              11              12            0.01
                                 Breeding.
----------------------------------------------------------------------------------------------------------------


[[Page 50844]]


                                 Table 8--Authorized Amount of Taking in Year 2
----------------------------------------------------------------------------------------------------------------
                                                                                                   Instances of
                                                                                                     take as a
            Species                   Stock           Level A         Level B          Total       percentage of
                                                                                                       stock
                                                                                                     abundance
----------------------------------------------------------------------------------------------------------------
Harbor porpoise...............  Northern OR/WA                 0              13              13            0.06
                                 Coast.
California sea lion...........  U.S.............               0              78              78            0.03
Steller sea lion..............  Eastern.........               0             337             337            0.78
Harbor seal...................  OR/CA Coastal...               0           5,252           5,252           21.24
Northern elephant seal........  California                     0               7               7           <0.01
                                 Breeding.
----------------------------------------------------------------------------------------------------------------

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.
    The Corps must employ the following standard mitigation measures, 
as included in their application and the IHAs:
     The Corps must conduct briefings between construction 
supervisors and crews and the marine mammal monitoring team prior to 
the start of all pile driving activity, and when new personnel join the 
work, to ensure that responsibilities, communication procedures, marine 
mammal monitoring protocols, and operational procedures are clearly 
understood;
     For in-water work other than pile driving/removal (e.g., 
stone placement, use of barge-mounted excavators, or dredging), if a 
marine mammal comes within 10 m (33 ft), operations shall cease. Should 
a marine mammal come within 10 m (33ft) of a vessel in transit, the 
boat operator will reduce vessel speed to the minimum level required to 
maintain steerage and safe working conditions. If human safety is at 
risk, the in-water activity will be allowed to continue until it is 
safe to stop;
     In-water work activities may only occur when PSOs can 
effectively visually monitor for the presence of marine mammals, and 
when the entire shutdown zone and adjacent waters are visible (e.g., 
including during daylight hours and when monitoring effectiveness is 
not reduced due to rain, fog, snow, etc.).
     For all pile driving/removal activities, the Corps must 
establish a minimum 15 m (49 ft) shutdown zone. 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). Shutdown zones 
will vary based on the type of driving/removal activity type and by 
marine mammal hearing group (see Table 9). Here, shutdown zones are 
larger than the calculated Level A harassment isopleth shown in Table 
6, except for harbor porpoises, harbor seals, and northern elephant 
seals during impact driving of 24-inch steel piles when a 100-m 
shutdown zone will be visually monitored;

                                Table 9--Shutdown Zones During Project Activities
----------------------------------------------------------------------------------------------------------------
                                                                                   Distance  (m)
               Activity                     Pile description     -----------------------------------------------
                                                                        HF              PW              OW
----------------------------------------------------------------------------------------------------------------
Impact Installation (attenuated)......  24-inch steel pipe pile.             100             100              15
Vibratory Installation................  24-inch steel pipe pile.              50              15              15
                                        24-inch AZ steel sheets.              50              15              15
                                        12-inch steel H-piles...              15              15              15
Vibratory Removal.....................  24-inch steel pipe pile.              15              15              15
                                        24-inch AZ steel sheets.              50              15              15
                                        12-inch steel H-piles...              15              15              15
----------------------------------------------------------------------------------------------------------------

     The Corps must delay or shutdown all pile driving 
activities should an animal approach or enter the appropriate shutdown 
zone. The Corps may resume activities after one of the following 
conditions have been met: (1) the animal is observed exiting the 
shutdown zone; (2) the animal is thought to have exited the shutdown

[[Page 50845]]

zone based on a determination of its course, speed, and movement 
relative to the pile driving location; or (3) the shutdown zone has 
been clear from any additional sightings for 15 minutes;
     The Corps will employ PSOs trained in marine mammal 
identification and behaviors to monitor marine mammal presence in the 
action area, and must establish the following monitoring locations: 
during vibratory driving, at least one PSO must be stationed on the 
shoreline near the Port of Garibaldi to monitor as much of the Level B 
harassment zone as possible, and another PSO must be stationed on the 
shoreline adjacent to the MOF site to monitor the shutdown zone; during 
impact pile driving, two PSOs must be stationed on the shoreline 
adjacent to the MOF site to monitor the shutdown zone. The Corps must 
monitor the project area to the maximum extent possible based on the 
required number of PSOs, required monitoring locations, and 
environmental conditions. For all pile driving and removal at least two 
PSOs must be used;
     The placement of the PSOs during all pile driving and 
removal activities will ensure that the entire Level A harassment and 
shutdown zones are visible during pile installation and removal;
     Monitoring must take place from 30 minutes prior to 
initiation of pile driving (i.e., pre-clearance monitoring) through 30 
minutes post-completion of pile driving;
     If in-water work ceases for more than 30 minutes, the 
Corps will conduct pre-clearance monitoring of both the Level B 
harassment zone and shutdown zone;
     Pre-start clearance monitoring must be conducted during 
periods of visibility sufficient for the lead PSO to determine that the 
shutdown zones indicated in 9are 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;
     Marine mammals observed anywhere within visual range of 
the PSO will be tracked relative to construction activities. If a 
marine mammal is observed entering or within the shutdown zones 
indicated in Table 9, pile driving must be delayed or halted. If pile 
driving 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 
(Table 9), or 15 minutes have passed without re-detection of the 
animal;
     Vibratory hammers are the preferred method for installing 
piles at the MOF. If impact hammers are required to install steel 
piles, a confined bubble curtain must be used to minimize noise levels. 
The bubble curtain must adhere by the following restrictions:
    (1) The bubble curtain must distribute air bubbles around 100 
percent of the piling circumference for the full depth of the water 
column;
    (2) The lowest bubble ring must be in contact with the substrate 
for the full circumference of the ring, and the weights attached to the 
bottom ring shall ensure 100 percent substrate contact. No parts of the 
ring or other objects shall prevent full substrate contact; and
    (3) Air flow to the bubblers must be balanced around the 
circumference of the pile;
     The Corps 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 thirty-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 
thirty minutes or longer. Soft starts will not be used for vibratory 
pile installation and removal. PSOs shall begin observing for marine 
mammals 30 minutes before ``soft start'' or in-water pile installation 
or removal begins;
     Pile driving activity must be halted upon observation of 
either 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;
    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:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Monitoring must be conducted by qualified, NMFS-approved PSOs, in 
accordance with the following:
     PSOs must be independent (i.e., not construction 
personnel) 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 IHA. 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 IHA. PSOs must be approved by NMFS

[[Page 50846]]

prior to beginning any activity subject to these IHAs; and
     PSOs will be placed at two vantage points as 
aforementioned in the Mitigation section (see Figure 1-3 of the Corps' 
IHA Application) to monitor for marine mammals and implement shutdown/
delay procedures when applicable by calling for the shutdown to the 
hammer operator;
     PSOs will use a hand-held GPS device or rangefinder to 
verify the required monitoring distance from the project site;
     PSOs will scan the waters within the Level A harassment 
and Level B harassment zones using binoculars (10x42 or similar) or 
spotting scopes (20-60 zoom or equivalent) and make visual observations 
of marine mammals present; and
     PSOs must record all observations of marine mammals, 
regardless of distance from the pile being driven. PSOs shall document 
any behavioral reactions in concert with distance from piles being 
driven or removed.
    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, 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;
    Additionally, the Corps will have PSOs conduct one pinniped 
monitoring count a week prior to construction and report the number of 
marine mammals present within 500 m (1640 ft) of the Tillamook South 
Jetty or MOF. Upon completion of jetty repairs, PSOs will conduct two 
post-construction monitoring events, with one approximately 4 weeks 
after construction, and another at 8 weeks post construction. These 
post-construction marine mammal surveys will help to determine whether 
marine mammal detections post-construction were comparable to surveys 
conducted prior to construction.

Reporting

    Draft marine mammal monitoring reports will be submitted to NMFS 
within 90 days after the completion of pile driving (Year 1 IHA) and 
removal activities (Year 2 IHA), or 60 days prior to a requested date 
of issuance of any future IHAs for projects at the same location, 
whichever comes first. The reports will include an overall description 
of work completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the reports 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 or vibratory) and the total 
equipment duration for vibratory installation and 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: 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, sex class, 
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);
     Number of marine mammals detected within the harassment 
zones and shutdown zones, by species;
     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;
     Description of other human activity within each monitoring 
period;
     Description of any deviation from initial proposal in pile 
numbers, pile types, average driving times, etc.;
     Brief description of any impediments to obtaining reliable 
observations during construction period; and
     Description of any impediments to complying with these 
mitigation measures.
    If no comments are received from NMFS within 30 days, the draft 
final reports will constitute the final reports. 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 IHA-holder 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, the Corps 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 IHAs. The Corps 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

[[Page 50847]]

     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 discussion of our analysis applies to all 
the species listed in Table 2, other than harbor seals, given that the 
anticipated effects of this activity on these marine mammal stocks are 
expected to be similar. For harbor seals, there are meaningful 
differences in the amount of take; therefore, we provide a supplemental 
analysis for harbor seals, independent of the other species for which 
we authorize take.
    Pile driving activities associated with the Corps' construction 
activities, 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 B harassment (behavioral 
disturbance), and for some species, Level A harassment incidental to 
underwater sounds generated from pile driving. Takes could occur if 
individuals are present in zones ensonified above the thresholds for 
Level B harassment and Level A harassment, identified above, while 
activities are underway. NMFS does not anticipate that serious injury 
or mortality will occur as a result of the Corps' planned activity 
given the nature of the activity, even in the absence of required 
mitigation. For all species and stocks, take will occur within a 
limited, confined area (adjacent to the project site) of the stock's 
range. Required mitigation is expected to minimize the duration and 
intensity of the authorized taking by Level A and Level B harassment. 
Further, the amount of take authorized is extremely small for 4 of the 
5 species when compared to stock abundance.
    The primary method of installation will be vibratory pile driving. 
Vibratory pile driving produces lower SPLs than impact pile driving. 
The rise time of the sound produced by vibratory pile driving is 
slower, reducing the probability and severity of injury. Impact pile 
driving produces short, sharp pulses with higher peak levels and much 
sharper rise time to reach those peaks. If impact pile driving is used, 
implementation of soft start measures, a bubble curtain, and shutdown 
zones will significantly reduce any possibility of injury. Given 
sufficient notice through use of soft starts (for impact driving), 
marine mammals are expected to move away from a sound source prior to 
it becoming potentially injurious. The Corps will use two PSOs 
stationed strategically to increase detectability of marine mammals 
during pile installation and removal, enabling a high rate of success 
in implementation of shutdowns to avoid injury for most species.
    Instances of Level A harassment take are not authorized for 
California sea lions and Steller sea lions in Year 1 or for any species 
in Year 2. Instances of Level A harassment takes are authorized for 
nine harbor porpoises, one northern elephant seal, and 653 harbor seals 
in Year 1. All of these Level A harassment takes are attributed to 
impact pile driving, which if implemented, will only occur 
intermittently on up to nine days with the required mitigation measures 
described above, minimizing potential for take by Level A harassment. 
In addition, the calculated Level A harassment likely overestimates PTS 
exposure because: (1) individuals are unlikely to remain in the Level A 
harassment zone long enough to accumulate sufficient exposure to noise 
resulting in PTS, and (2) the estimates assume new individuals are in 
the Level A harassment zone every day during impact pile driving. 
Further, should individuals be repeatedly exposed to accumulated sound 
energy, impact pile driving will only occur intermittently for up to 
nine days, minimizing any severe impacts to individual fitness, 
reproduction, or survival. Nonetheless, we have considered the 
potential impacts of these PTS takes occurring in this analysis. Due to 
the levels and durations of likely exposure, animals that experience 
PTS will likely only receive slight PTS, i.e., minor degradation of 
hearing capabilities within regions of hearing that align most 
completely with the frequency range of the energy produced by pile 
driving (i.e., the low-frequency region below 2 kilohertz (kHz)), not 
severe hearing impairment or impairment in the reigns of greatest 
hearing sensitivity. If hearing impairment does occur, it is most 
likely that the affected animal will lose a few dBs in its hearing 
sensitivity, which in most cases, is not likely to meaningfully affect 
its ability to forage and communicate with conspecifics.
    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 TTS incurred will not be 
expected to adversely impact individual fitness, let alone annual rates 
of recruitment or survival.
    Behavioral responses of marine mammals to pile driving and removal 
in Tillamook Bay 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 or 
increased haul out time (Thorson and Reyff, 2006). Given that pile 
driving and removal will occur intermittently for only a short duration 
(20-23 days in Year 1 and 13 days in Year 2), often on nonconsecutive 
days, any harassment occurring will be temporary. Additionally, many of 
the species present in the 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. 
Most likely, individuals will simply move away from the sound source 
and be temporarily displaced from the areas of pile driving, although 
even this reaction

[[Page 50848]]

has been observed primarily only in association with impact pile 
driving, which will only be used if necessary. The pile driving 
activities analyzed here are similar to, or less impactful than, other 
construction activities conducted in Oregon, which have taken place 
with no known long-term adverse consequences from behavioral 
harassment. Level B harassment will be reduced to the level of least 
practicable adverse impact through use of mitigation measures described 
herein and, if sound produced by project activities is sufficiently 
disturbing, animals are likely to simply avoid the area while the 
activity is occurring.
    The Corps' activities are limited in scope spatially. While precise 
impacts will not be known until the MOF has been designed, based on a 
MOF built for a similar project (The Coos Bay North Jetty Maintenance 
project, https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-army-corps-engineers-north-jetty-maintenance-and-repairs), it is estimated that temporary impacts below the high tide 
line (HTL) will be limited to 0.14 acres or less. The full extent of 
the MOF and associated access dredging will be approximately 3.6 acres, 
with an additional 3.7 acres of upland disturbance associated with the 
MOF staging area. For all species, there are no known habitat areas of 
particular importance (e.g., Biologically Important Areas (BIAs), 
critical habitat, primary foraging or calving habitat) in the project 
area that will be impacted by the Corps' activities. In general, 
cetaceans and pinnipeds are infrequent visitors near the site of the 
Corps' construction activities due to shallow waters in this region 
further reducing the likelihood that cetaceans and pinnipeds will 
approach and be present within the ensonified areas. Further, none of 
the harassment isopleths block the entrance out of Tillamook Bay (see 
Figures 6-1 and 6-2 in the Corps' application), thus marine mammals 
could leave the bay and engage in foraging, social behavior or other 
activities without being subject to Level A or Level B harassment.
    The impact of harassment on harbor seals is difficult to assess 
given the most recent abundance estimate available for this stock is 
from 1999 (Table 2). We are aware that there is one haul-out site 
located approximately 1.5 km (0.9 mi) east of the Corps' construction 
site on an intertidal sand flat in the middle of the bay (see Figure 4-
1 in the Corps' application) that has been historically noted in 
Tillamook Bay. Given the Level B harassment distances for vibratory 
installation and removal of 24-inch steel pipe piles and 24-inch AZ 
steel sheets are larger than 1.5 km (0.9 mi) (see Table 6), we can 
presume that some harbor seals will be repeatedly taken. In addition, 
while there are no known pinniped haul outs on Bayocean split, harbor 
seals and other pinnipeds may be resting or hauled out on land near the 
site of the MOF construction, jetty rocks, or nearby beaches. Repeated, 
sequential exposure to pile driving noise over a long duration could 
result in more severe impacts to individuals that could affect a 
population; however, the limited number of non-consecutive pile driving 
days for this project means that these types of impacts are not 
anticipated.
    The project also is not expected to have significant adverse 
effects on affected marine mammal habitat. The project activities will 
not modify existing marine mammal habitat for a significant amount of 
time. Any impacts on marine mammal prey that will occur during the 
Corps' 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. The activities may cause some 
fish to leave the area of disturbance, thus temporarily impacting 
marine mammal foraging opportunities in a limited portion of the 
foraging range. However, because of the short duration of the 
activities and the small area of the habitat that may be affected, the 
impacts to marine mammal habitat are not expected to cause significant 
or long-term negative consequences. 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.
    In addition, it is unlikely that minor noise effects in a small, 
localized area of habitat will have any effect on 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 effects of the specified activities 
will have only minor, short-term effects on individuals. The specified 
activities are not expected to impact rates of recruitment or survival 
and will, 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;
     For all species except harbor seals in Year 1, only a few 
individuals are expected to incur PTS in any year (nine harbor 
porpoises in Year 1, one elephant seal in Year 1, and zero individuals 
for all other species and years), and any single instance of exposure 
above the PTS threshold is expected to result in only a small degree of 
hearing loss, which is not expected to impact reproduction or 
survivorship of any individuals;
     Though the higher predicted numbers of harbor seal PTS in 
Year 1 suggest that there may be repeated exposures of some number of 
individuals above PTS thresholds, which could potentially result in a 
greater degree of PTS accrued to those individuals, given the 
intermittency (non-consecutive days) of the pile driving and the 
anticipated duration and levels of exposure, still only a relatively 
small degree of hearing loss is anticipated and not expected to impact 
reproduction or survival;
     The Corps will implement mitigation measures including 
soft-starts and shutdown zones 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;
     Take will not occur in places and/or times where take will 
be more likely to accrue to impacts on reproduction or survival, such 
as within BIAs, or other habitats critical to recruitment or survival 
(e.g., rookery);
     Take will occur over a short timeframe (i.e., 
intermittently over up to 23 and 13 non-consecutive days in Year 1 and 
Year 2, respectively). This short timeframe minimizes the probability 
of multiple exposures on individuals, and any repeated exposures that 
do occur (which are more likely for harbor seals) are not expected to 
occur on sequential days, decreasing the likelihood of physiological 
impacts caused by chronic stress or sustained energetic impacts that 
might affect survival or reproductive success;
     Any impacts to marine mammal habitat from pile driving 
(including to prey sources as well as acoustic habitat, e.g., from 
masking) are expected to be temporary and minimal; and
     Take will only occur within a small portion of Tillamook 
Bay--a limited, confined area of any given stock's home range.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into

[[Page 50849]]

consideration the implementation of the monitoring and mitigation 
measures, NMFS finds, specific for both the Year 1 and Year 2 IHAs, 
that the total marine mammal take from the Corps' activity will have a 
negligible impact on all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under 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.
    The amount of take NMFS authorizes is below one third of the 
estimated stock abundance for all but one species (in fact, take of 
individuals is less than two percent of the abundance of four of the 
five affected stocks, see Tables 7 and 8). The estimated instances of 
take as percentages of stock abundance shown in the Tables 7 and 8 are 
if we assume all takes are of different individual animals, which is 
likely not the case. Some individuals may return multiple times in a 
day, but PSOs will count them as separate takes if they cannot be 
individually identified. More importantly, due to their behavior in the 
area, some individuals will likely be taken on multiple days, resulting 
in a lower number of individuals taken than the predicted number of 
instances in Tables 7 and 8.
    There is no current estimate of abundance available for this harbor 
seals (Carretta et al., 2021). In 1999, aerial surveys of harbor seals 
in Oregon and Washington were conducted by the National Marine Mammal 
Laboratory (NMLL) and the Oregon and Washington Departments of Fish and 
Wildlife (ODFW and WDFD) during the pupping season. After applying a 
correction factor to account for seals missed during aerial surveys 
(Huber et al., 2001), they estimated that the population size of the 
Oregon/Washington Coast Stock of harbor seals was 24,732 (CV = 0.12) in 
1999. Historical and current trends of harbor seal abundance in Oregon 
and Washington are unknown. Based on the analyses of Jeffries et al. 
(2003) and Brown et al. (2005), both the Washington and Oregon portions 
of this stock were reported as reaching carrying capacity. While the 
authorized instances of take for harbor seals equates to 37.57 percent 
of the 1999 abundance estimate in Year 1 and 21.24 percent of this 
abundance in Year 2, harbor seals are not known to make extensive 
migrations and are known to display strong fidelity to haul out sites 
(Pitcher and Calkins, 1979; Pitcher and McAllister, 1981). Therefore, 
we presume that some of the harbor seals present in the action area 
will be repeatedly taken and actual number of individuals exposed to 
Level A and Level B harassment will be much lower. Further, we 
calculated take estimates of harbor seals assuming the maximum seasonal 
abundance of individuals were present in Tillamook Bay during each 
action day; however, work may occur during other times of the year when 
harbor seal abundance is estimated to be lower, and thus the actual 
number of individuals exposed to Level A and Level B harassment will be 
lower. Lastly, take will occur in a small portion of Tillamook Bay and 
it is unlikely that a third of the stock will be in these waters during 
the short duration of the Corps' activities.
    Based on the analysis contained herein of the Corps' activity 
(including the mitigation and monitoring measures) and the anticipated 
take of marine mammals, NMFS finds, for both the Year 1 and Year 2 
IHAs, 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 Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species.
    No incidental take of ESA-listed species is authorized or expected 
to result from the Corps' activities. 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 evaluate our action (i.e., the issuance of two IHAs) and 
alternatives with respect to potential impacts on the human 
environment. This action is consistent with categories of activities 
identified in Categorical Exclusion B4 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 this action qualifies to be categorically excluded from further 
NEPA review.

Authorization

    NMFS has issued two IHAs to the Corps' for the potential harassment 
of small numbers of five marine mammal species incidental to conducting 
repairs of the Tillamook South Jetty in Tillamook Bay, Oregon, that 
includes the previously explained mentioned mitigation, monitoring and 
reporting requirements.

    Dated: August 12, 2022.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2022-17775 Filed 8-17-22; 8:45 am]
BILLING CODE 3510-22-P