Notice2022-17775
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Tillamook South Jetty Repairs in Tillamook Bay, Oregon
Primary source
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Published
August 18, 2022
Effective
November 1, 2022
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
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.
Full Text
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<title>Federal Register, Volume 87 Issue 159 (Thursday, August 18, 2022)</title>
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[Federal Register Volume 87, Number 159 (Thursday, August 18, 2022)]
[Notices]
[Pages 50836-50849]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. 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
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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\
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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
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Project Totals 284 49.83 hours..... 16.17 hours..... ........... ............ ............ ........... 14-20 17-23 8-13
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\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
(L<INF>E,p</INF>) 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; <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these
species (e.g., physical and behavioral descriptions) may be found on
NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>).
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)
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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).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a> assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. 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 (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>) 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:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
[[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:
<bullet> 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;
<bullet> 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;
<bullet> 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.).
<bullet> 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
----------------------------------------------------------------------------------------------------------------
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
Visual Monitoring
Monitoring must be conducted by qualified, NMFS-approved PSOs, in
accordance with the following:
<bullet> 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
<bullet> 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;
<bullet> PSOs will use a hand-held GPS device or rangefinder to
verify the required monitoring distance from the project site;
<bullet> 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
<bullet> 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:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary;
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:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including the number and type of piles driven or
removed and by what method (i.e., impact 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);
<bullet> PSO locations during marine mammal monitoring;
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
<bullet> Upon observation of a marine mammal, the following
information: Name of PSO who sighted the animal(s) and PSO location and
activity at time of sighting; Time of sighting; Identification of the
animal(s) (e.g., genus/species, lowest possible taxonomic level, or
unidentified), PSO confidence in identification, and the composition of
the group if there is a mix of species; Distance and bearing of each
marine mammal observed relative to the pile being driven for each
sighting (if pile driving was occurring at time of sighting); Estimated
number of animals (min/max/best estimate); Estimated number of animals
by cohort (adults, juveniles, neonates, group composition, 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);
<bullet> Number of marine mammals detected within the harassment
zones and shutdown zones, by species;
<bullet> Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting changes in behavior of the
animal(s), if any;
<bullet> Description of other human activity within each monitoring
period;
<bullet> Description of any deviation from initial proposal in pile
numbers, pile types, average driving times, etc.;
<bullet> Brief description of any impediments to obtaining reliable
observations during construction period; and
<bullet> 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)
(<a href="/cdn-cgi/l/email-protection#0353512d4a57532d4e6c6d6a776c716a6d645166736c717770436d6c62622d646c75"><span class="__cf_email__" data-cfemail="0252502c4b56522c4f6d6c6b766d706b6c655067726d707671426c6d63632c656d74">[email protected]</span></a>), 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:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
[[Page 50847]]
<bullet> General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338;
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the 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, <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-army-corps-engineers-north-jetty-maintenance-and-repairs">https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-army-corps-engineers-north-jetty-maintenance-and-repairs</a>), 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:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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);
<bullet> 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;
<bullet> 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
<bullet> 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
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