[Federal Register Volume 87, Number 122 (Monday, June 27, 2022)]
[Notices]
[Pages 38116-38141]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-13605]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC074]


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; proposed incidental harassment authorizations; request 
for comments on proposed authorizations and possible renewals.

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SUMMARY: NMFS has received a request from the U.S. Army Corps of 
Engineers (USACE)--Portland District (Corps) for authorization to take 
marine mammals incidental to 2 years of activity associated with 
Tillamook South Jetty Repairs in Tillamook Bay, Oregon. Pursuant to the 
Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue two one-year incidental harassment authorizations 
(IHAs) to incidentally take marine mammals during the specified 
activities. NMFS is also requesting comments on a possible one-time, 
one-year renewal for each IHA that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorization and agency responses will be 
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than July 27, 
2022.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email to 
<a href="/cdn-cgi/l/email-protection#064f5256287463687f727f7569686b69697463466869676728616970"><span class="__cf_email__" data-cfemail="2d64797d035f48435459545e42434042425f486d43424c4c034a425b">[email protected]</span></a>.
    Instructions: NMFS is not responsible for comments sent by any 
other method,

[[Page 38117]]

to any other address or individual, or received after the end of the 
comment period. Comments, including all attachments, must not exceed a 
25-megabyte file size. All comments received are a part of the public 
record and will generally be posted online at www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying information (e.g., name, 
address) voluntarily submitted by the commenter may be publicly 
accessible. Do not submit confidential business information or 
otherwise sensitive or protected information.

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

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed actions (i.e., the issuance of two IHAs) 
with respect to potential impacts on the human environment.
    These actions are consistent with categories of activities 
identified in Categorical Exclusion B4 (IHAs with no anticipated 
serious injury or mortality) of the Companion Manual for NOAA 
Administrative Order 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 preliminarily determined that the issuance of the 
proposed IHAs qualifies to be categorically excluded from further NEPA 
review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA requests.

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 Proposed Activity

Overview

    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 
``proposed activities'') would complete critical repairs to the South 
Jetty, as described in the MMR, with a focus on rebuilding the South 
Jetty head. Work would 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, 
and placement operations. A temporary material offload facility (MOF), 
which would be approximately 15 meters (m) (50 feet (ft)) by 30 m (100 
ft), would be constructed to transfer jetty rock from barges to shore 
at the South Jetty.
    The two IHAs requested by the Corps would be associated with the 
construction (Year 1 IHA) and removal (Year 2 IHA) of the temporary 
MOF. Construction of the MOF would 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), and is anticipated to occur during the first year of the project 
(November 1, 2022 through October 31, 2023). Removal of the MOF would 
involve vibratory extraction of all installed piles and sheets and is 
anticipated to occur between November 1, 2024 and October 31, 2025. The 
Corps proposed 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 these 
proposed activities may result in the incidental take of marine mammals 
by Level A and Level B harassment.

Dates and Duration

    Completion of the South Jetty repairs is anticipated to take 
multiple construction seasons. The primary in-water sound effects would 
be associated with construction (Year 1 IHA) and deconstruction (Year 2 
IHA) of a MOF at Kincheloe Point. MOF construction/deconstruction would 
only occur during the aforementioned work windows and when weather 
conditions would not restrict watercraft operations or compromise crew 
safety. The Corps anticipates commencing work in the autumn of 2022. 
Construction of the

[[Page 38118]]

MOF 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. Deconstruction of the MOF is estimated 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. The Corps plans to conduct 
pile driving only during daylight hours (from sunrise to sunset).

Specific Geographic Region

    Tillamook Bay is located on the Oregon Coast near the city of 
Garibaldi in Tillamook County, Oregon (Figure 1). The Bay is protected 
from the open ocean by shoals and a sandbar called the Bayocean 
Peninsula. It is generally very shallow, with depths ranging from 0.3 
to 2.1 m (1 to 7 ft) throughout most of the Bay, but reaching depths of 
up to 10 m (32 ft) in the South, Main, and Bay City Channels. The 
sediment in Tillamook Bay consists primarily of sand or mud, and there 
are several sea grass beds present in the region. Tillamook Bay 
provides a safe harbor for the water-dependent economies of local and 
state entities. It is the third largest bay in Oregon and sustains 
significant biological and economic resources. The proposed activities 
would be located on the Bayocean Split, Tillamook County, Oregon 
(Tillamook Bay, River Mile 1; Section 18, 19, and 20 of Township 1N, 
Range 10W; Latitude: 45.565500, Longitude: -123.948983).
[GRAPHIC] [TIFF OMITTED] TN27JN22.001

    The Port of Garibaldi is located approximately 3.2 kilometers (km) 
(2 miles (mi)) east of the entrance to Tillamook Bay and contains a 
lumber mill, seafood processing plants, marine repair shops, a 
commercial and charter fishing marina, and a public boat launch. The 
United States Coast Guard (USCG) Station Tillamook Bay is also located 
at the Port of Garibaldi; operations include towing vessels and 
assisting recreational and commercial boaters throughout the year with 
five search and rescue boats. The U.S. Highway 101 corridor is adjacent 
to Tillamook Bay, passing through the coastal cities of Bay City, 
Garibaldi, and Barview closest to the South Jetty (see Figure 1-1 in 
the Corps' application). The nearest residences to the proposed 
activity area are located in Barview, approximately 610 m (2,000 ft) 
away on the opposite side of the entrance channel.

Detailed Description of Specific Activity

    The purpose of the proposed activities is to protect the structural 
integrity of the Tillamook South Jetty and to improve navigation 
conditions at the channel entrance through major maintenance repair 
activities. As with most jetties along the Oregon coast, the Tillamook 
South Jetty was constructed to facilitate safe navigation and support a 
more stable entrance channel at the mouth of Tillamook Bay. It was

[[Page 38119]]

constructed in phases between 1969 and 1979 to a final length of 2,046 
m (8,025 ft). The South Jetty currently has a total length that is 
approximately 320 m (1,050 ft) shorter than the authorized footprint, 
and the head is severely damaged with an estimated recession rate of 
approximately 8.5 m (28 ft) per year. As with the Tillamook North 
Jetty, there has also been erosion of the jetty trunk. No repairs have 
occurred since the original construction. The 2003 MMR report and 
subsequent 2014 Corps inspection recommended several repair actions 
that are the basis for the proposed construction activities. Repair 
activities would consist of two main components at the South Jetty: 
trunk repairs and construction of a 30 m (100-ft) cap to repair the 
South Jetty head.
    In addition to stone placement at the South Jetty head and trunk, 
related construction activities associated with these repairs, 
specifically the delivery and storage of new stone, include the 
construction of a temporary MOF near Kincheloe Point; channel dredging 
to maintain access to MOF; roadway improvements and possible turnouts 
along Bayocean Dike Road; and utilization of two upland staging and 
stockpiling areas: one primary staging area adjacent to the South Jetty 
trunk and a smaller staging area near the MOF. The Contractor will 
ultimately decide on the means and methods for construction, within 
these constraints and the conditions outlined in the proposed IHAs. 
Given uncertainty about which features will be implemented to 
facilitate site access, the Corps' application assumes a temporary MOF, 
which requires pile driving, would be constructed to accommodate barge 
operations. The proposed activities also include removal and site 
restoration for each of the temporary construction features upon 
project completion. As discussed in further detail below, NMFS assumes 
that take of marine mammals is likely to result only from pile driving 
activities conducted as part of the MOF construction/removal and not 
from activities related to the delivery, storage, or placement of jetty 
stone.

Construction Staging Areas

    Jetty repairs and associated construction elements require areas 
for equipment and supply staging and storage, parking areas, access 
roads, scales, general yard requirements, and jetty stone stockpile 
areas. There would be one primary staging area adjacent to the South 
Jetty trunk and a smaller staging area near the MOF (Figure 1). 
Temporary erosion controls would be put in place before any alteration 
of the sites. An Erosion and Sediment Control Plan (ESCP) would outline 
facilities and Best Management Practices (BMPs) that would be 
implemented and installed prior to any ground-disturbing activities on 
the project site, including mobilization. These erosion controls would 
prevent pollution caused by surveying or construction operations and 
ensure sediment-laden water do not leave the project site, enter 
Tillamook Bay, or impact aquatic and terrestrial wildlife.
    Ocean barging is anticipated to be the primary method of material 
and equipment transport; however, Bayocean Dike Road (Figure 1) would 
be used to access the staging areas and work sites. Prior to 
construction, the road would be improved to facilitate the necessary 
level of construction traffic. Specific details and locations of road 
improvement actions would depend on the condition of the road at the 
start of construction, however any improvements or alterations would 
avoid wetlands and waters of the U.S. to the maximum extent 
practicable. Roadway improvements would also avoid any locations 
identified as having significant cultural resources.
    There are no known pinnipeds haul-outs on the sites proposed for 
these staging areas or near the proposed access roads (see Description 
of Marine Mammals in the Area of Specified Activities). Therefore, 
upland activities related to the development of the staging areas and 
access roads are not anticipated to impact any marine mammal species, 
and are not considered further in our analysis.

Temporary Material Offloading Facility

    A temporary MOF is needed to transfer jetty rock from barges to 
shore at the South Jetty. The MOF would provide moorage for barges and 
a structure for crane support. The preferred location of the MOF is on 
the south side of Kincheloe Point, on the site of a former staging area 
(Figure 1). Detailed design of the MOF would be completed closer to the 
time of construction. The discussion below is based on general 
assumptions about likely design elements. These assumptions represent a 
conservative scenario for purposes of analysis.
    The offloading platform could require the use of an anchor line 
moorage or dolphins. The platform would be approximately 15 m (50 ft) 
by 30 m (100 ft) and would be constructed using a sheet pile perimeter 
wall, installed using a vibratory hammer. A maximum of 24, 24-inch 
timber or steel piles would be installed as mooring dolphins, up to 10, 
12-inch steel H-piles will be installed for support, and up to 250, 24-
inch steel sheets (type NZ, AZ, PZ, or SCZ) would be driven for the 
perimeter wall. The maximum pile diameter would be 24 inches, and caps 
(or other deterrence devices) would be installed on each pile to 
discourage birds from perching. The platform would be constructed 
within the confines of the perimeter wall by filling in the area with 
backfill. The H-piles would be shoreward of installed sheets and most 
likely driven into the fill material with very little water, if any. A 
contractor would be limited by these general constraints, but the final 
MOF design would be per their discretion, largely based on site 
conditions, material availability, and cost. The MOF would be sited to 
avoid direct impacts to eelgrass during construction. In-water noise 
incidental to vibratory and impact pile driving of the MOF is 
anticipated to result in Level A harassment and/or Level B harassment.
    Vibratory hammers are the preferred method of pile installation. 
However, impact driving may be required for steel pipe piles if 
vibratory means prove infeasible (impact pile driving would not be 
required for any other pile type). For any impact driving of steel 
piles, a confined bubble curtain will be used to reduce in-water sound. 
Pile driving to construct the MOF is anticipated to take 20 (vibratory 
installation methods only) to 23 (vibratory and impact installation 
methods) days over the course of a month (Table 1) and would occur 
under the first IHA (Year 1). Multiple piles would not be driven 
concurrently. Vibratory hammers would be used to remove the temporary 
MOF and is anticipated to take an additional 13 days over the course of 
a month (Table 1). Deconstruction would occur under the second IHA 
(Year 2).

[[Page 38120]]



                                   Table 1--Summary of Pile Details and Estimated Effort Required for the Construction and Deconstruction of the Temporary MOF
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                                                                                                                            Production rate  (piles/day)             Range of
                                                                                                           Potential -----------------------------------------   installation days     Range of
                                                      Number of       Vibratory        Vibratory  removal    impact                                               anticipated \1\     vibratory
             Pile type                     Size        sheets/       installation      duration per pile/   strikes                                           ----------------------   removal
                                                        piles     duration per pile/    sheet  (minutes)   per pile,  Installation  Installation    Removal               Vibratory      days
                                                                   sheet  (minutes)                        if needed   (vibratory)     (impact)   (vibratory)  Vibratory     and     anticipated
                                                                                                                                                                  only      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.

Dredging

    In order to allow fully loaded barges to access the MOF, dredging 
would occur prior to the construction of the platform. Based on the 
conditions at the preferred MOF location, it is conservatively 
estimated that no more than 5,000 cubic yards of material would be 
dredged. The barge route from the main channel to the MOF will be sited 
to avoid potential adverse effects to eelgrass to the maximum extent 
practicable. The area dredged would include the area adjacent to the 
shore where the barge would be moored (see Figure 1-4 in the Corps' 
application). Sandy dredged material removed to facilitate barge access 
would be placed in the Primary Staging Area as indicated in Figure 1-3 
in the Corps' application and used to fill depressions and create 
better habitat for WSP post construction.
    The scope and duration of dredging would be limited to the minimum 
area and amount of time needed to achieve project purposes. Initial MOF 
dredging would take approximately one week to complete, and will occur 
between July 15 and March 15 to avoid the peak timing for juvenile coho 
salmon outmigration. Ongoing maintenance will occur as needed. Only 
mechanical dredging would be permissible, and dredges would be operated 
to limit dredge spillover.
    The Corps will work to meet state water quality standards. To 
minimize water turbidity and the potential for entrainment of organisms 
during dredging for the MOF, the clamshell bucket or head of the dredge 
would remain on the bottom to the greatest extent possible and only be 
raised 1 m (3 ft) off the bottom when necessary for dredge operations. 
Turbidity levels will be monitored via visual observations to identify 
any adverse detectable change in water quality. A hand-held turbidity 
meter will be deployed and used during MOF dredging and fill 
activities. No more than 10 percent cumulative increase in natural 
stream turbidities may be allowed, as measured relative to a control 
point immediately upstream of the turbidity causing activity. However, 
limited duration activities necessary to address an emergency or to 
accommodate essential dredging, construction, or other legitimate 
activities and which cause the standard to be exceeded may occur 
provided all practicable turbidity control techniques have been 
applied. See Oregon Administrative Rules (OAR) 340-041-0036.
    While dredging may produce underwater noise above the relevant 
harassment threshold (i.e., between 150 and 180 dB; Clark et al., 2002; 
Miles et al., 1986), the noise produced by dredging is similar to other 
common on-and in-water industrial activities typically occurring in the 
area. Additionally, dredging will only occur in a relatively small and 
confined area of Tillamook Bay over a short duration of time (i.e., 5 
days), limiting the potential for impacts. Therefore, incidental takes 
of marine mammals are not anticipated or proposed to be authorized for 
dredging activities, and this activity is not considered further in our 
analysis.

South Jetty Maintenance and Repairs

    Significant repairs are proposed along the South Jetty, where the 
majority of work would occur from STA 70+00 westward. These stations 
are enumerated in 30 m (100-ft) increments such that STA 71+00 would be 
30 m (100 ft) seaward from STA 70+00. Additional repairs to the jetty 
trunk between Stations 43+00 and 49+00 are also planned. The jetty cap 
will be from STA 77+00 to 77+75 to elevation + 5.5 m (18 ft) relative 
to North American Vertical Datum of 1988 (NAVD88). From the final head 
station centerline, the end of the jetty will be built out in a 6 m (20 
ft) radius to elevation + 5.5 m (18 ft) NAVD88. The crest width of the 
jetty cap would be 12 m (40 ft). The crest width of the jetty trunk 
would be 9 m (30 ft) with a target crest elevation of + 5.5 m (18 ft) 
NAVD88. The average stone density would be approximately 180 pounds 
(lbs)/ft\3\, and the total quantity of stone required for the proposed 
activities is estimated at 31,000 cubic yards (~76,000 tons). Stone 
placement at the South Jetty would take just under 150 working days.
    While placement of jetty stone could produce noise, NMFS has 
determined that sounds produced from this action would not exceed 
marine mammal thresholds beyond 10 m (33 ft) from the source in the 
water and beyond 100 m (328 ft) from the source in the air (86 FR 
22151; April 27, 2021). There are no known pinniped haul-outs or other 
known important marine mammal habitats within the vicinity of the South 
Jetty (see Description of Marine Mammals in the Area of Specified 
Activities) limiting the potential for impacts from stone placement. 
Therefore, incidental takes of marine mammals are not anticipated or 
proposed to be authorized for jetty stone placement, and are not 
considered further in our analysis.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

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

[[Page 38121]]

of reprinting the information. Additional information regarding 
population trends and threats may be found in NMFS' Stock Assessment 
Reports (SARs; www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general 
information about these species (e.g., physical and behavioral 
descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species or stocks for which take is expected and 
proposed to be 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 represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Pacific SARs (e.g., Carretta et al. 2021) or Alaska SARs 
(e.g., Muto et al. 2020). All values presented in Table 2 are the most 
recent available at the time of publication and are available in the 
2020 SARs (Carretta et al. 2021, Muto et al., 2020) and draft 2021 SARs 
(available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

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

    As indicated above, all 5 species (with 5 managed stocks) in Table 
2 temporally and spatially co-occur with the activity to the degree 
that take is reasonably likely to occur. All species (26 marine mammal 
species and 27 marine mammal stocks) that could potentially occur in 
the proposed survey 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 km/12 
mi offshore) or in deeper waters offshore and would 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 would not extend beyond the bay 
entrance (please see Estimated Take), there is no reasonable 
expectation for the proposed 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 
proposed project 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

[[Page 38122]]

noise resulting from the construction/deconstruction of the MOF would 
be limited to the interior waters of the bay and would 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 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.

Harbor Porpoise

    In the Pacific Ocean, harbor porpoise are found in coastal and 
inland waters from Point Conception, California to Alaska and across to 
Kamchatka and Japan (Gaskin, 1984). Six harbor porpoise stocks have 
been designated off California/Oregon/Washington, based on genetic 
analyses and density discontinuities identified from aerial surveys. 
While harbor porpoise are rare within Tillamook Bay, if present, 
animals likely belong to the Northern Oregon/Washington Coast stock, 
which is delimited from Cape Flattery, Washington (located 
approximately 320 km (198 mi) north of Tillamook Bay), to Lincoln City, 
Oregon (located approximately 68 km (42 mi) south of Tillamook Bay) 
(Carretta et al., 2022).
    Entanglement is the primary cause of human-related injury and death 
for harbor porpoises, however, estimated fishery mortality and serious 
injury rates are well below PBR. Harbor porpoises are sensitive to 
disturbance by a variety of anthropogenic sound sources, and the 
limited range of several U.S. West Coast harbor porpoise stocks makes 
them particularly vulnerable to potential impacts (see overview in 
Forney et al., 2017).
    Harbor porpoises on the Pacific Northwest coast of the United 
States are typically found in waters roughly 100-200 m (328-656 ft) 
deep (NOAA, 2013a; Holdman et al. 2018). They occur along the Oregon 
coast year-around and may be slightly more abundant in summer and 
exhibit diel or tidal movement patterns related to prey availability 
(Holdman et al., 2018). Harbor porpoises have been detected within a 16 
km (10 mi) radius of the Tillamook Bay entrance channel (Halpin et al., 
2009; OBIS-SEAMAP, 2022), and they could potentially occur in the 
project vicinity during the proposed activities.

California Sea Lion

    California sea lions are distributed along the North Pacific waters 
from central Mexico to southeast Alaska, with breeding areas restricted 
primarily to island areas off southern California (the Channel 
Islands), Baja California, and in the Gulf of California (Carretta et 
al., 2021). There are five genetically distinct geographic populations. 
The population seen in Oregon is the Pacific Temperate population 
(which comprises the U.S. stock managed by NMFS), which are commonly 
seen in Oregon from September through May (ODFW, 2015).
    The occurrence of the California sea lion along the Oregon coast is 
seasonal with lowest abundance in Oregon in the summer months, from May 
to September, as they migrate south to the Channel Islands in 
California to breed. They are commonly found in Oregon haul-out sites 
from September to May and during this period, adult and subadult males 
have been observed in bays, estuaries, and offshore rocks along the 
Oregon coast. In fact, a few males have been reported in Oregon waters 
throughout the year (Mate, 1973). The population breeds in the 
California Channel Islands and most females and young pups remain in 
that region year-around (Mate, 1973).
    The California sea lion stock has been growing steadily since the 
1970s. The stock is estimated to be approximately 40 percent above its 
maximum net productivity level (MNPL = 183,481 animals), and it is 
therefore considered within the range of its optimum sustainable 
population (OSP) size (Laake et al., 2018). The stock is also near its 
estimated carrying capacity of 275,298 animals (Laake et al., 2018). 
However, there remain many threats to California sea lions including 
entanglement, intentional kills, harmful algal blooms, and climate 
change. For example, for each 1 degree Celsius increase in sea surface 
temperature (SST), the estimated odds of survival declined by 50 
perfect for pups and yearlings, while negative SST anomalies resulted 
in higher survival estimates (DeLong et al., 2017). Such declines in 
survival are related to warm oceanographic conditions (e.g., El 
Ni[ntilde]o) that limit prey availability to pregnant and lactating 
females (DeLong et al., 2017). Changes in prey abundance and 
distribution have been linked to warm-water anomalies in the California 
Current that have impacted a wide range of marine taxa (Cavole et al., 
2016), including California sea lions. For example, between 2013 and 
2017, NOAA declared an unusual mortality event (UME) for California sea 
lions as high mortality of pup and juvenile age classes were documented 
during this time. NOAA identified changes in the availability of sea 
lion prey species, particularly sardines, as a contributing factor.
    California sea lions may occur in the project vicinity, but there 
have been no confirmed sightings in Tillamook Bay (Halpin et al., 2009; 
OBIS-SEAMAP, 2022). The closest known haul out site is at Three Arch 
Rock, which is approximately 23 km (14 mi) south of the proposed site 
of the MOF.

Steller Sea lion

    The Steller sea lion range extends along the Pacific Rim, from 
northern Japan to central California. For management purposes, Steller 
sea lions inhabiting U.S. waters have been divided into two DPS: the 
Western U.S. and the Eastern U.S. Steller sea lions encountered off the 
Oregon coast are part of the Eastern U.S. Stock, with rookeries in 
California, Oregon, Washington, Southeast Alaska, and British Columbia 
(Muto et al., 2021). The Western U.S. stock of Steller sea lions are 
listed as endangered under the ESA and depleted and strategic under the 
MMPA. The Eastern U.S. stock (including those living in Oregon) was de-
listed in 2013 following a population growth from 18,040 in 1979 to 
70,174 in 2010 (an estimated annual growth of 4.18 percent) (NMFS, 
2013). A population growth model indicates the eastern stock of Steller 
sea lions increased at a rate of 4.25 percent per year (95 percent 
confidence intervals of 3.77-4.72 percent) between 1987 and 2017 based 
on an analysis of pup counts in California, Oregon, British Columbia, 
and Southeast Alaska (Muto et al., 2021). This stock is likely within 
its OSP; however, no determination of its status relative to OSP has 
been made (Muto et al., 2021).
    Off the Oregon coast, Steller sea lions have been observed ashore 
from the Columbia River south to Rogue Reef and typically inhabit 
offshore rocks and

[[Page 38123]]

islands. There are seven major haul-out sites noted in Oregon during 
the breeding season, however, there are no known rookery sites near 
Tillamook Bay (Pitcher et al., 2007). The closest known haul out site 
is at Three Arch Rock, which is approximately 23 km (14 mi) south of 
the proposed site of the MOF. Steller sea lions have been detected in 
Tillamook Bay during marine mammal surveys (Pearson and Verts, 1970; 
Halpin et al., 2009; Ford et al., 2013) and may occur in the vicinity 
of the project.

Harbor Seal

    Harbor seals inhabit coastal and estuarine waters off Baja 
California, north along the western coasts of the continental U.S., 
British Columbia, and Southeast Alaska, west through the Gulf of Alaska 
and Aleutian Islands, and in the Bering Sea north to Cape Newenham and 
the Pribilof Islands (Caretta et al., 2021). Within U.S. west coast 
waters, five stocks of harbor seals are recognized: (1) Southern Puget 
Sound (south of the Tacoma Narrows Bridge); (2) Washington Northern 
Inland Waters (including Puget Sound north of the Tacoma Narrows 
Bridge, the San Juan Islands, and the Strait of Juan de Fuca); (3) Hood 
Canal; (4) Oregon/Washington Coast; and (5) California. Seals 
potentially affected by this activity would be part of the Oregon/
Washington Coast stock.
    Harbor seals generally are non-migratory, with local movements 
associated with tides, weather, season, food availability, and 
reproduction (Scheffer and Slipp, 1944; Fisher, 1952; Bigg 1969, 1981). 
Harbor seals do not make extensive pelagic migrations, though some long 
distance movement of tagged animals in Alaska (900 km, 559 mi) and 
along the U.S. west coast (up to 550 km, 342 mi) have been recorded 
(Brown and Mate, 1983; Herder, 1986; Womble, 2012). Harbor seals have 
displayed strong fidelity to haulout sites (Pitcher and Calkins, 1979; 
Pitcher and McAllister, 1981).
    Harbor seals were historically hunted in Oregon as a nuisance to 
fishermen, however, their numbers have steadily increased since the 
passage of the MMPA in 1972 (Harvey, 1987; Brown et al., 2005). While 
harbor seals are still subject to incidental take from commercial 
fisheries in the region, overall mortality is relatively low. However, 
the most recent abundance estimate available for this stock dates to 
1999 (Carretta et al., 2021).
    Harbor seals are one of the most abundant pinnipeds in Oregon and 
can typically be found in coastal marine and estuarine waters of the 
Oregon coast throughout the year. On land, they can be found on 
offshore rocks and islands, along shore, and on exposed flats in the 
estuary (Harvey, 1987). There is one haul-out site roughly 1.5 km (0.9 
mi) east of the proposed MOF that has been historically noted in 
Tillamook Bay. This haul-out is located on an intertidal sand flat in 
the middle of the bay (See Figure 4-1 in the Corps' application) and 
highest utilization has been observed during the May/June reproductive 
season (B.E. Wright, personal communication, February 12, 2021; ODFW, 
2022). This is consistent with other findings noting harbor seals being 
more abundant in Tillamook Bay during the summer pupping season (Brown 
and Mate, 1983). There is also evidence that animals may move between 
Netarts Bay, a prominent feeding site located approximately 15 km (9 
mi) south of Tillamook Bay, and Tillamook Bay in the non-pupping season 
(Brown and Mate, 1983). Therefore, harbor seals are expected to occur 
in the vicinity of the project.

Northern Elephant Seal

    The California Breeding Stock of Northern elephant seals breeds and 
gives birth in California and makes extended foraging trips to areas 
including coastal Oregon biannually during the fall and spring (Le 
Boeuf et al., 2000). While both males and females may transit areas off 
the Oregon coast, males seem to have focal forage areas near the 
continental shelf break while females typically move further offshore 
and feed opportunistically at numerous sites while in route (Le Beouf 
et al., 2000).
    Populations of northern elephant seals in the U.S. and Mexico have 
recovered after being nearly hunted to extinction (Stewart et al., 
1994). Northern elephant seals underwent a severe population bottleneck 
and loss of genetic diversity when the population was reduced to an 
estimated 10-30 individuals (Hoelzel et al., 2002). Although movement 
and genetic exchange continues between rookeries, most elephant seals 
return to natal rookeries when they start breeding (Huber et al., 
1991). The California breeding population is now demographically 
isolated from the Baja California population. No international 
agreements exist for the joint management of this species by the U.S. 
and Mexico. The California breeding population is considered to be a 
separate stock (Carretta et al., 2022).
    The population is currently susceptible to incidental take and 
injury from gillnet and trawl fisheries operating offshore, however, 
the human-caused mortality is still well below the estimated PBR level.
    There have been no recorded sightings of northern elephant seals in 
the immediate vicinity of Tillamook Bay, however, there have been 
sightings toward Netarts Bay, located approximately 14 km (9 mi) south 
of the Tillamook South Jetty, and further offshore (Halpin et al., 
2009; OBIS-SEAMAP, 2022). Therefore, northern elephant seals could 
transit the area.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 3.

[[Page 38124]]



                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

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

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a discussion of the ways that components of 
the specified activity may impact marine mammals and their habitat. The 
Estimated Take section later in this document includes a quantitative 
analysis of the number of individuals that are expected to be taken by 
this activity. The Negligible Impact Analysis and Determination section 
considers the content of this section, the Estimated Take section, and 
the Proposed Mitigation section, to draw conclusions regarding the 
likely impacts of these activities on the reproductive success or 
survivorship of individuals and whether those impacts are reasonably 
expected to, or reasonably likely to, adversely affect the species or 
stock through effects on annual rates of recruitment or survival
    Acoustic effects on marine mammals during the specified activity 
can occur from impact and vibratory pile driving. The effects of 
underwater noise from the Corps' proposed activities have the potential 
to result in Level A and Level B harassment of marine mammals in the 
action area.

Description of Sound Sources

    This section contains a brief technical background on sound, on the 
characteristics of certain sound types, and on metrics used in this 
proposal inasmuch as the information is relevant to the specified 
activity and to a discussion of the potential effects of the specified 
activity on marine mammals found later in this document. For general 
information on sound and its interaction with the marine environment, 
please see, e.g., Au and Hastings (2008); Richardson et al. (1995); 
Urick (1983).
    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in hertz (Hz) or cycles per second. Wavelength is the 
distance between two peaks or corresponding points of a sound wave 
(length of one cycle). Higher frequency sounds have shorter wavelengths 
than lower frequency sounds, and typically attenuate (decrease) more 
rapidly, except in certain cases in shallower water. Amplitude is the 
height of the sound pressure wave or the ``loudness'' of a sound and is 
typically described using the relative unit of the dB. A sound pressure 
level (SPL) in dB is described as the ratio between a measured pressure 
and a reference pressure (for underwater sound, this is 1 microPascal 
([mu]Pa)), and is a logarithmic unit that accounts for large variations 
in amplitude; therefore, a relatively small change in dB corresponds to 
large changes in sound pressure. The source level represents the SPL 
referenced at a distance of 1 m from the source (referenced to 1 
[mu]Pa), while the received level is the SPL at the listener's position 
(referenced to 1 [mu]Pa).
    Root mean square (RMS) is the quadratic mean sound pressure over 
the duration of an impulse. RMS is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick, 1983). RMS accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper, 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    Sound exposure level (SEL; represented as dB referenced to 1 
micropascal squared per second (re 1 [mu]Pa\2\-s)) represents the total 
energy in a stated frequency band over a stated time interval or event, 
and considers both intensity and duration of exposure. The per-pulse 
SEL is calculated over the time window containing the entire pulse 
(i.e., 100 percent of the acoustic energy). SEL is a cumulative metric; 
it can be accumulated over a single pulse, or calculated over periods 
containing multiple pulses. Cumulative SEL (SELcum) represents the 
total energy accumulated by a receiver over a defined time window or 
during an event. Peak sound pressure (also referred to as zero-to-peak 
sound pressure or 0-pk) is the maximum instantaneous sound pressure 
measurable in the water at a specified distance from the source, and is 
represented in the same units as the RMS sound pressure.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in a 
manner similar to ripples on the surface of a pond and may be either 
directed in a beam or beams or may radiate in all directions 
(omnidirectional sources), as is the case for sound produced by the 
pile driving activity considered here. The compressions and 
decompressions associated with sound waves are detected as changes in 
pressure by aquatic life and man-made sound receptors such as 
hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to

[[Page 38125]]

ambient sound, which is defined as the all-encompassing sound in a 
given place and is usually a composite of sound from many sources both 
near and far (ANSI, 1995). The sound level of a region is defined by 
the total acoustical energy being generated by known and unknown 
sources. These sources may include physical (e.g., wind and waves, 
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced 
by marine mammals, fish, and invertebrates), and anthropogenic (e.g., 
vessels, dredging, construction) sound. A number of sources contribute 
to ambient sound, including wind and waves, which are a main source of 
naturally occurring ambient sound for frequencies between 200 Hz and 50 
kilohertz (kHz) (Mitson, 1995). In general, ambient sound levels tend 
to increase with increasing wind speed and wave height. Precipitation 
can become an important component of total sound at frequencies above 
500 Hz, and possibly down to 100 Hz during quiet times. Marine mammals 
can contribute significantly to ambient sound levels, as can some fish 
and snapping shrimp. The frequency band for biological contributions is 
from approximately 12 Hz to over 100 kHz. Sources of ambient sound 
related to human activity include transportation (surface vessels), 
dredging and construction, oil and gas drilling and production, 
geophysical surveys, sonar, and explosions. Vessel noise typically 
dominates the total ambient sound for frequencies between 20 and 300 
Hz. In general, the frequencies of anthropogenic sounds are below 1 kHz 
and, if higher frequency sound levels are created, they attenuate 
rapidly.
    A recent study of ambient ocean sound for Oregon's nearshore 
environment observed maximum and minimum levels of 136 dB re 1 [mu]Pa 
and 95 dB re 1 [mu]Pa, respectively, with an average level of 113 dB re 
1 [mu]Pa over a period of one year (Haxel et al., 2011). This level 
could vary given the presence of different recreational and commercial 
vessels (e.g., up to 150 dB for small fishing vessels (Hildebrand, 
2005), up to 186 dB for large vessels, 81 to 166 dB for empty tugs and 
barges and up to 170 dB for loaded tugs and barges (Richardson et al., 
1995) within the frequencies between 20 and 5000 Hz), or other factors 
(e.g., wind and waves, traffic noise along adjacent roadways, aquatic 
animals, currents, etc.) as described above. No direct data on ambient 
noise levels within Tillamook Bay are available; however, in-water 
ambient noise levels are considered comparable to similar bays.
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project may 
include impact pile driving, and vibratory pile driving and removal. 
The sounds produced by these activities fall into one of two general 
sound types: impulsive and non-impulsive. Impulsive sounds (e.g., 
explosions, gunshots, sonic booms, impact pile driving) are typically 
transient, brief (less than 1 second), broadband, and consist of high 
peak sound pressure with rapid rise time and rapid decay (ANSI, 1986; 
NIOSH, 1998; NMFS, 2018). Non-impulsive sounds (e.g., aircraft, 
machinery operations such as drilling or dredging, vibratory pile 
driving, and active sonar systems) can be broadband, narrowband or 
tonal, brief or prolonged (continuous or intermittent), and typically 
do not have the high peak sound pressure with rapid rise/decay time 
that impulsive sounds do (ANSI, 1995; NIOSH, 1998; NMFS, 2018). The 
distinction between these two sound types is important because they 
have differing potential to cause physical effects, particularly with 
regard to hearing (e.g., Ward 1997 in Southall et al. 2007).
    Two types of hammers would be used on this project: impact and 
vibratory. Impact hammers operate by repeatedly dropping and/or pushing 
a heavy piston onto a pile to drive the pile into the substrate. Sound 
generated by impact hammers is characterized by rapid rise times and 
high peak levels, a potentially injurious combination (Hastings and 
Popper, 2005). Vibratory hammers install piles by vibrating them and 
allowing the weight of the hammer to push them into the sediment. 
Vibratory hammers produce significantly less sound than impact hammers. 
Peak SPLs may be 180 dB or greater, but are generally 10 to 20 dB lower 
than SPLs generated during impact pile driving of the same-sized pile 
(Oestman et al., 2009). Rise time is slower, reducing the probability 
and severity of injury, and sound energy is distributed over a greater 
amount of time (Nedwell and Edwards, 2002; Carlson et al., 2005).
    The likely or possible impacts of the Corps' proposed activities on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of the equipment and personnel; however, given there are no 
known pinniped haul-out sites in the vicinity of the proposed site of 
the MOF construction/deconstruction, visual and other non-acoustic 
stressors would be limited, and any impacts to marine mammals are 
expected to primarily be acoustic in nature. Acoustic stressors include 
effects of heavy equipment operation during pile installation and 
removal.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal is the primary means by which 
marine mammals may be harassed from the Corps' specified activities. In 
general, animals exposed to natural or anthropogenic sound may 
experience physical and psychological effects, ranging in magnitude 
from none to severe (Southall et al., 2007, 2019). In general, exposure 
to pile driving noise has the potential to result in auditory threshold 
shifts and behavioral reactions (e.g., avoidance, temporary cessation 
of foraging and vocalizing, changes in dive behavior). Exposure to 
anthropogenic noise can also lead to non-observable physiological 
responses such an increase in stress hormones. Additional noise in a 
marine mammal's habitat can mask acoustic cues used by marine mammals 
to carry out daily functions such as communication and predator and 
prey detection. The effects of pile driving noise on marine mammals are 
dependent on several factors, including, but not limited to, sound type 
(e.g., impulsive vs. non-impulsive), the species, age and sex class 
(e.g., adult male vs. mom with calf), duration of exposure, the 
distance between the pile and the animal, received levels, behavior at 
time of exposure, and previous history with exposure (Wartzok et al., 
2004; Southall et al., 2007). Here we discuss physical auditory effects 
(threshold shifts)

[[Page 38126]]

followed by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral). When analyzing the auditory effects of noise exposure, it is 
often helpful to broadly categorize sound as either impulsive or non-
impulsive. When considering auditory effects, vibratory pile driving is 
considered a non-impulsive source while impact pile driving is treated 
as an impulsive source.
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Available data 
from humans and other terrestrial mammals indicate that a 40 dB 
threshold shift approximates PTS onset (see Ward et al., 1958, 1959; 
Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; 
Henderson et al., 2008). PTS levels for marine mammals are estimates, 
as with the exception of a single study unintentionally inducing PTS in 
a harbor seal (Kastak et al., 2008), there are no empirical data 
measuring PTS in marine mammals largely due to the fact that, for 
various ethical reasons, experiments involving anthropogenic noise 
exposure at levels inducing PTS are not typically pursued or authorized 
(NMFS, 2018).
    Temporary Threshold Shift (TTS)--A temporary, reversible increase 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2018). Based on data from cetacean TTS measurements (see 
Southall et al. 2007), a TTS of 6 dB is considered the minimum 
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et 
al., 2000; Finneran et al., 2000, 2002). As described in Finneran 
(2015), marine mammal studies have shown the amount of TTS increases 
with SELcum in an accelerating fashion: at low exposures with lower 
SELcum, the amount of TTS is typically small and the growth curves have 
shallow slopes. At exposures with higher SELcum, the growth curves 
become steeper and approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
masking, below). For example, a marine mammal may be able to readily 
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal 
is traveling through the open ocean, where ambient noise is lower and 
there are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts. We note that reduced hearing sensitivity as 
a simple function of aging has been observed in marine mammals, as well 
as humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several decibels above (a 40-dB threshold shift approximates PTS onset; 
e.g., Kryter et al., 1966; Miller, 1974) that inducing mild TTS (a 6-dB 
threshold shift approximates TTS onset; e.g., Southall et al., 2007). 
Based on data from terrestrial mammals, a precautionary assumption is 
that the PTS thresholds for impulse sounds (such as impact pile driving 
pulses as received close to the source) are at least 6 dB higher than 
the TTS threshold on a peak-pressure basis and PTS cumulative sound 
exposure level thresholds are 15 to 20 dB higher than TTS cumulative 
sound exposure level thresholds (Southall et al., 2007). Given the 
higher level of sound or longer exposure duration necessary to cause 
PTS as compared with TTS, it is considerably less likely that PTS could 
occur.
    TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. 
Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin), beluga whale (Delphinapterus leucas), harbor 
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis)) 
and five species of pinnipeds exposed to a limited number of sound 
sources (i.e., mostly tones and octave-band noise) in laboratory 
settings (Finneran, 2015). TTS was not observed in trained spotted 
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive 
noise at levels matching previous predictions of TTS onset (Reichmuth 
et al., 2016). In general, harbor seals and harbor porpoises have a 
lower TTS onset than other measured pinniped or cetacean species 
(Finneran, 2015). Additionally, the existing marine mammal TTS data 
come from a limited number of individuals within these species. No data 
are available on noise-induced hearing loss for mysticetes. For 
summaries of data on TTS in marine mammals or for further discussion of 
TTS onset thresholds, please see Southall et al. (2007), Finneran and 
Jenkins (2012), Finneran (2015), and Table 5 in NMFS (2018).
    Construction and deconstruction of the MOF, which is required to 
repair the Tillamook South Jetty, requires a combination of impact pile 
driving and vibratory pile driving. During this project, these 
activities will not occur at the same time and there will be pauses in 
activities producing the sound during each day. Given these pauses and 
that many marine mammals are likely moving through the project area and 
not remaining for extended periods of time, the potential for TTS 
declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal also has the potential to behaviorally disturb marine mammals. 
Behavioral disturbance may include a variety of effects, including 
subtle changes in behavior (e.g., minor or brief avoidance

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of an area or changes in vocalizations), more conspicuous changes in 
similar behavioral activities, and more sustained and/or potentially 
severe reactions, such as displacement from or abandonment of high-
quality habitat. Disturbance may result in changing durations of 
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral 
activities (such as socializing or feeding); eliciting a visible 
startle response or aggressive behavior (such as tail/fin slapping or 
jaw clapping); avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound 
are highly variable and context-specific and any reactions depend on 
numerous intrinsic and extrinsic factors (e.g., species, state of 
maturity, experience, current activity, reproductive state, auditory 
sensitivity, time of day), as well as the interplay between factors 
(e.g., Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 
2007; Weilgart, 2007; Archer et al., 2010). Behavioral reactions can 
vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
In general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. Please see Appendices B and C of Southall et 
al. (2007) and Gomez et al. (2016) for reviews of studies involving 
marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al., 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
(Eubalaena glacialis) have been observed to shift the frequency content 
of their calls upward while reducing the rate of calling in areas of 
increased anthropogenic noise (Parks et al., 2007). In some cases, 
animals may cease sound production during production of aversive 
signals (Bowles et al., 1994).

[[Page 38128]]

    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996, Bowers et al., 2018). The result of a flight response 
could range from brief, temporary exertion and displacement from the 
area where the signal provokes flight to, in extreme cases, marine 
mammal strandings (Evans and England, 2001). However, it should be 
noted that response to a perceived predator does not necessarily invoke 
flight (Ford and Reeves, 2008), and whether individuals are solitary or 
in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003), however 
distress is an unlikely result of this project based on observations of 
marine mammals during previous, similar construction projects.
    Auditory Masking--Since many marine mammals rely on sound to find 
prey, moderate social interactions, and facilitate mating (Tyack, 
2008), noise from anthropogenic sound sources can interfere with these 
functions, but only if the noise spectrum overlaps with the hearing 
sensitivity of the marine mammal (Southall et al., 2007; Clark et al., 
2009; Hatch et al., 2012). Chronic exposure to excessive, though not 
high-intensity, noise could cause masking at particular frequencies for 
marine mammals that utilize sound for vital biological functions (Clark 
et al., 2009). Acoustic masking is when other noises such as from human 
sources interfere

[[Page 38129]]

with an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al., 1995; Erbe et al., 2016). 
Therefore, under certain circumstances, marine mammals whose acoustical 
sensors or environment are being severely masked could also be impaired 
from maximizing their performance fitness in survival and reproduction. 
The ability of a noise source to mask biologically important sounds 
depends on the characteristics of both the noise source and the signal 
of interest (e.g., signal-to-noise ratio, temporal variability, 
direction), in relation to each other and to an animal's hearing 
abilities (e.g., sensitivity, frequency range, critical ratios, 
frequency discrimination, directional discrimination, age or TTS 
hearing loss), and existing ambient noise and propagation conditions.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
when disrupting or altering critical behaviors. It is important to 
distinguish TTS and PTS, which persist after the sound exposure, from 
masking, which occurs during the sound exposure. Because masking 
(without resulting in TS) is not associated with abnormal physiological 
function, it is not considered a physiological effect, but rather a 
potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore, 2014). Masking can be tested 
directly in captive species (e.g., Erbe, 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).
    Marine mammals in Tillamook Bay are exposed to anthropogenic noise 
which may lead to some habituation, but is also a source of masking. 
Vocalization changes may result from a need to compete with an increase 
in background noise and include increasing the source level, modifying 
the frequency, increasing the call repetition rate of vocalizations, or 
ceasing to vocalize in the presence of increased noise (Hotchkin and 
Parks, 2013).
    Masking is more likely to occur in the presence of broadband, 
relatively continuous noise sources. Energy distribution of pile 
driving covers a broad frequency spectrum, and sound from pile driving 
would be within the audible range of pinnipeds and cetaceans present in 
the proposed action area. While some pile driving during the Corps' 
activities may mask some acoustic signals that are relevant to the 
daily behavior of marine mammals, the short-term duration and limited 
areas affected make it very unlikely that survival would be affected.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal that have the potential to cause behavioral harassment, 
depending on their distance from these activities. Airborne noise would 
primarily be an issue for pinnipeds that are swimming or hauled out 
near the project site within the range of noise levels elevated above 
the acoustic criteria. However, given that the closest known haul outs 
are approximately 1.5 km (0.9 mi) away for harbor seals and 
approximately 23 km (14 mi) or greater for California sea lions, 
Steller sea lions, and northern elephant seals, the likelihood of 
pinnipeds being exposed to airborne noise over the short duration of 
intermittent pile driving and removal is low.
    We recognize that pinnipeds in the water could be exposed to 
airborne sound that may result in behavioral harassment when looking 
with their heads above water. Most likely, airborne sound would cause 
behavioral responses similar to those discussed above in relation to 
underwater sound. For instance, anthropogenic sound could cause hauled-
out pinnipeds to exhibit changes in their normal behavior, such as 
reduction in vocalizations, or cause them to temporarily abandon the 
area and move further from the source. However, these animals would 
previously have been `taken' because of exposure to underwater sound 
above the behavioral harassment thresholds, which are in all cases 
larger than those associated with airborne sound. Thus, the behavioral 
harassment of these animals is already accounted for in these estimates 
of potential take. Therefore, we do not believe that authorization of 
incidental take resulting from airborne sound for pinnipeds is 
warranted, and airborne sound is not discussed further here.

Marine Mammal Habitat Effects

    The Corps' proposed activities would not result in permanent 
negative impacts to habitats used directly by marine mammals, but may 
have potential short-term impacts to food sources such as forage fish 
and may affect acoustic habitat (see masking discussion above). There 
are no known foraging hotspots or other ocean bottom structure of 
significant biological importance to marine mammals present in the 
marine waters of the project area. The Corps' proposed activities in 
Tillamook Bay could have localized, temporary impacts on marine mammal 
habitat and their prey by increasing in-water sound pressure levels and 
slightly decreasing water quality. During impact pile driving and 
vibratory pile driving or removal, elevated levels of underwater noise 
would ensonify a portion of Tillamook Bay where both fishes and mammals 
occur and could affect foraging success. Additionally, marine mammals 
may avoid the area during construction, however, displacement due to 
noise is expected to be temporary and is not expected to result in 
long-term effects to the individuals or populations. The proposed 
construction activities are of short duration and would likely have 
temporary impacts on marine mammal habitat through increases in 
underwater and airborne sound.
    Pile installation/removal may temporarily increase turbidity 
resulting from suspended sediments. Any increases would be temporary, 
localized, and minimal. In general, turbidity associated with pile 
installation is localized to about a 7.6 m

[[Page 38130]]

(25 ft) radius around the pile (Everitt et al., 1980). Cetaceans and 
pinnipeds in Tillamook Bay are not expected to be close enough to the 
project pile driving areas to experience effects of turbidity; however, 
if they were they could avoid localized areas of turbidity. Therefore, 
the impact from increased turbidity levels is expected to minimal for 
marine mammals. Furthermore, pile driving and removal at the project 
site would not obstruct movements or migration of marine mammals.
    Potential Pile Driving Effects on Prey--Sound from pile driving may 
affect marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton). Marine mammal prey varies by species, season, and 
location. Here, we describe studies regarding the effects of noise on 
known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). Depending on their hearing anatomy and peripheral sensory 
structures, which vary among species, fishes hear sounds using pressure 
and particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds that are especially strong and/or intermittent 
low-frequency sounds. Short duration, sharp sounds can cause overt or 
subtle changes in fish behavior and local distribution. The reaction of 
fish to noise depends on the physiological state of the fish, past 
exposures, motivation (e.g., feeding, spawning, migration), and other 
environmental factors. Hastings and Popper (2005) identified several 
studies that suggest fish may relocate to avoid certain areas of sound 
energy. Additional studies have documented effects of pile driving on 
fish; several are based on studies in support of large, multiyear 
bridge construction projects (e.g., Scholik and Yan, 2001, 2002; Popper 
and Hastings, 2009). Several studies have demonstrated that impulse 
sounds might affect the distribution and behavior of some fishes, 
potentially impacting foraging opportunities or increasing energetic 
costs (e.g., Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski 
et al., 1992; Santulli et al., 1999; Paxton et al., 2017). However, 
some studies have shown no or slight reaction to impulse sounds (e.g., 
Pena et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; 
Cott et al., 2012). More commonly, though, the impacts of noise on fish 
are temporary.
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality (summarized in Popper et al., 2014). However, in 
most fish species, hair cells in the ear continuously regenerate and 
loss of auditory function likely is restored when damaged cells are 
replaced with new cells. Halvorsen et al. (2012a) showed that a TTS of 
4-6 dB was recoverable within 24 hours for one species. Impacts would 
be most severe when the individual fish is close to the source and when 
the duration of exposure is long. Injury caused by barotrauma can range 
from slight to severe and can cause death, and is most likely for fish 
with swim bladders. Barotrauma injuries have been documented during 
controlled exposure to impact pile driving (Halvorsen et al., 2012b; 
Casper et al., 2013).
    The most likely impact to fish from pile driving and removal 
activities at the project area would be temporary behavioral avoidance 
of the area. The duration of fish avoidance of this area after pile 
driving stops is unknown, but a rapid return to normal recruitment, 
distribution, and behavior is anticipated. In general, impacts to 
marine mammal prey species are expected to be minor and temporary due 
to the short timeframe of the project.
    In summary, given the short daily duration of sound associated with 
individual pile driving and the small area being affected relative to 
available nearby habitat, pile driving activities associated with the 
proposed action are not likely to have a permanent, adverse effect on 
any fish habitat, or populations of fish species or other prey. Any 
behavioral avoidance by fish of the disturbed area would still leave 
significantly large areas of fish and marine mammal foraging habitat in 
the nearby vicinity. Thus, we conclude that impacts of the specified 
activity are not likely to have more than short-term adverse effects on 
any prey habitat or populations of prey species. Further, any impacts 
to marine mammal habitat are not expected to result in significant or 
long-term consequences for individual marine mammals, or to contribute 
to adverse impacts on their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization 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 would 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 
proposed 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 proposed to be authorized for this activity. Below we 
describe how the proposed 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 proposed take estimates.

[[Page 38131]]

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' proposed 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' 
proposed activity includes the use of impulsive (impact pile driving) 
and non-impulsive (vibratory pile driving/removal) sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 4--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: 1183 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: 1185 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) (Underwater).....  Cell 7: Lp,0-pk.flat: 218   Cell 8: LE,p,PW,24h: 201 dB.
                                          dB; LE,p,PW,24h: 1185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lp,0-pk,flat: 232   Cell 10: LE,p,OW,24h: 219 dB.
                                          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 proposed project. 
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 Proposed 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 5). 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.

[[Page 38132]]



   Table 5--Estimates of Underwater Sound Levels Generated During Vibratory and Impact Pile Installation, and
                                             Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
                                                  Source       Source       Source
     Pile driving method            Pile        level (dB    level (dB    level (dB            Reference
                                description       peak)         RMS)         SEL)
----------------------------------------------------------------------------------------------------------------
Impact (attenuated \1\).....  24-inch steel            198          184          173  CALTRANS (2020).
                               pipe pile.
Vibratory (installation and   24-inch steel            177          161  ...........  Navy (2015).
 removal; unattenuated).       pipe pile.      ...........          163          163  CALTRANS (2020).
                              24-inch AZ
                               steel sheets.
                              12-inch steel H-         165          150          147  CALTRANS (2020).
                               piles.
----------------------------------------------------------------------------------------------------------------
\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 would lie between spherical 
and cylindrical spreading loss conditions, which is the most 
appropriate assumption for the Corps' proposed construction activities 
in the absence of specific modelling. All Level B harassment isopleths 
are reported in Table 7 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 6.

                                                          Table 6--NMFS User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                  Impact pile                                             Vibratory pile driving
                                    driving     --------------------------------------------------------------------------------------------------------
                                 installation                        Installation                                           Removal
                              --------------------------------------------------------------------------------------------------------------------------
                                 24-inch steel     24-inch steel   24-inch AZ steel  12-inch steel H-   24-inch steel      24-inch AZ    12-inch steel H-
                                   pipe pile         pipe pile          sheets             piles          pipe pile       steel sheets        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 7--Distances to Level A Harassment, by Hearing Group, and Level B Harassment Thresholds per Pile Type and Pile Driving Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Level A harassment distance (m)    Level A      Level B      Level B
                                                                                 ---------------------------------  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

[[Page 38133]]

 
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 
will 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 proposed for authorization.
    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 potential 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' proposed activities in Year 1 and 13 
(vibratory removal only) total days of noise exposure from pile driving 
during the Corps' proposed 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 days are required (i.e., 23 days). 
Takes for Year two assume that 13 total action days are required. A 
summary of take proposed for authorization is available in Tables 8 and 
9.

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 
7) and the proposed shutdown zone (see the Proposed Mitigation 
section). Therefore, the Corps proposed that all harbor porpoises in 
Tillamook Bay on days when impact pile driving occurs would be taken by 
Level A harassment. NMFS concurs with this estimate and proposes to 
authorize 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 proposes to authorize 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 proposes to authorize 
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 
proposed to be authorized. Considering the small Level A harassment 
zones (Table 7) in comparison to the required shutdown zones (see the 
Proposed 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

[[Page 38134]]

km (14 mi) from the proposed site of the MOF, was used to estimate 
daily occurrence by the Corps. Given the distance of this haul out site 
from the proposed 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 would 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 proposes to authorize 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 
proposes to authorize 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 proposed to be 
authorized for Year 1 or Year 2. Considering the small Level A 
harassment zones (Table 1) in comparison to the required shutdown zones 
(see the Proposed 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 proposed 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 proposed 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 would be present (i.e., we assume 
that 29 individual Steller sea lions would be present each day in 
Tillamook Bay).
    During Year 1, NMFS proposes to authorize 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 
proposes to authorize 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 proposed to be authorized for 
Year 1 or Year 2. The Level A harassment zones (Table 1) are smaller 
than the required shutdown zones (see the Proposed 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 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 Nov--Feb and Jul--Aug proposed 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 would 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 would be present (i.e., we assume 
that 404 individual harbor seals would be present each day in Tillamook 
Bay).
    During Year 1, NMFS estimates that 9,292 total instances of take 
for harbor seals would 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 would 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 would 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 would be implemented 
for harbor seals (see Table 10 in the Proposed Mitigation section), an 
area of approximately 0.07 km\2\ would still be ensonified above the 
Level A harassment threshold for phocids (Table 7). Given this 
remaining Level A harassment area for phocids is 17.95 percent of the 
Level B harassment area (0.39 km\2\), NMFS proposes to authorize 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 proposes to authorize the 
remaining 8,639 instances of take by Level B harassment.
    During Year 2, NMFS proposes to authorize 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 proposed to be 
authorized. The Level A harassment zones (Table 1) are smaller than the 
required shutdown zones (see the Proposed 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

[[Page 38135]]

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 would be 5 individuals (1 
elephant seal every other day x 9 total action days; Table 1). While a 
100 m shutdown zone would be implemented for northern elephant seals 
during impact pile driving (see Table 10 in the Proposed Mitigation 
section), an area of approximately 0.07 km\2\ would still be ensonified 
above the Level A harassment threshold for phocids during this activity 
(Table 7). 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 proposes to authorize 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). We 
propose that the remaining 11 instances of take be by Level B 
harassment.
    During Year 2, the Corps requested and we propose 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 proposed to be 
authorized. The Level A harassment zones (Table 1) are smaller than the 
required shutdown zones (see the Proposed 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 8--Proposed Authorized Amount of Taking in Year 1
----------------------------------------------------------------------------------------------------------------
                                                                                                    Percent of
            Species                   Stock           Level A         Level B          Total           stock
----------------------------------------------------------------------------------------------------------------
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.
----------------------------------------------------------------------------------------------------------------


                             Table 9--Proposed Authorized Amount of Taking in Year 2
----------------------------------------------------------------------------------------------------------------
                                                                                                    Percent of
            Species                   Stock           Level A         Level B          Total           stock
----------------------------------------------------------------------------------------------------------------
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.
----------------------------------------------------------------------------------------------------------------

Proposed 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 proposed 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 would reduce vessel speed to the minimum level required 
to maintain steerage and safe working conditions. If human safety is at 
risk,

[[Page 38136]]

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 would 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 10). Here, shutdown zones are 
larger than the calculated Level A harassment isopleth shown in Table 
7, 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 10--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 
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 proposed MOF site to monitor the shutdown 
zone; during impact pile driving, two PSOs must be stationed on the 
shoreline adjacent to the proposed 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 Table 10 are clear of marine mammals. Pile 
driving may commence following 30 minutes of observation when the 
determination is made that the shutdown zones are clear of marine 
mammals;
    <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 10, 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 10), 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:
    [cir] The bubble curtain must distribute air bubbles around 100 
percent of the piling circumference for the full depth of the water 
column;
    [cir] 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
    [cir] 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

[[Page 38137]]

number of takes has been met, entering or within the harassment zone;
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed 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.

Proposed 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 prior to beginning any 
activity subject to these IHAs; and
    <bullet> PSOs would be placed at two vantage points as 
aforementioned in the Proposed 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 would use a hand-held GPS device or rangefinder to 
verify the required monitoring distance from the project site;
    <bullet> PSOs would 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 would 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 would help to determine whether 
marine mammal detections post-construction were comparable to surveys 
conducted prior to construction.

Reporting

    Draft marine mammal monitoring reports would 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 would 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

[[Page 38138]]

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 would 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#1b4b4935524f4b35567475726f746972757c497e6b74696f685b75747a7a357c746d"><span class="__cf_email__" data-cfemail="db8b89f5928f8bf596b4b5b2afb4a9b2b5bc89beabb4a9afa89bb5b4babaf5bcb4ad">[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
    <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, given that the anticipated effects of 
this activity on these different marine mammal stocks are expected to 
be similar. There is little information about the nature or severity of 
the impacts, or the size, status, or structure of any of these species 
or stocks that would lead to a different analysis for this activity.
    Pile driving activities associated with the Corps' proposed 
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. Potential 
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 would 
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 would 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 proposed to be 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

[[Page 38139]]

species. If an animal was exposed to accumulated sound energy, the 
resulting PTS would likely be small (e.g., PTS onset) at lower 
frequencies where pile driving energy is concentrated, and unlikely to 
result in impacts to individual fitness, reproduction, or survival.
    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 potentially incurred here 
would 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 would 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 would be temporary. 
Additionally, many of the species present in the region would only be 
present temporarily based on seasonal patterns or during transit 
between other habitats. These temporarily present species would be 
exposed to even smaller periods of noise-generating activity, further 
decreasing the impacts.
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from other 
similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring) (e.g., Thorson and Reyff, 
2006). 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 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' proposed activities are limited in scope spatially. 
While precise impacts would not be known until the MOF has been 
designed, based on an MOF built for a similar project (The Coos Bay 
North Jetty Maintenance project, https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-army-corps-engineers-north-jetty-maintenance-and-repairs), it is estimated that temporary impacts below 
the high tide line (HTL) would be limited to 0.14 acres or less. The 
full extent of the MOF and associated access dredging would 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 would be impacted by the 
Corps' proposed activities. While takes may occur during important 
feeding or breeding times, the project area represents a small portion 
of available foraging and breeding habitat and impacts on marine mammal 
feeding and breeding for all species should be minimal. In general, 
cetaceans and pinnipeds are infrequent visitors near the site of the 
proposed 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 proposed 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 7), we can 
presume that some harbor seals will be repeatedly taken. In addition, 
while no 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 would 
not modify existing marine mammal habitat for a significant amount of 
time. Any impacts on marine mammal prey that would occur during the 
Corps' planned activity would 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 would 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 potential effects of the specified 
activities would have only minor, short-term effects on individuals. 
The specified activities are not expected to impact rates of 
recruitment or survival and would, therefore, not result in population-
level impacts.
    In summary and as described above, the following factors primarily 
support our preliminary 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;

[[Page 38140]]

    <bullet> The number of total takes (by Level A and Level B 
harassment) are less than 2 percent of the best available abundance 
estimates for all but one stock;
    <bullet> The Corps would 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 would not occur in places and/or times where take 
would 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 would 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 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 would 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 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds, specific to both the 
Year 1 and Year 2 proposed IHAs, that the total marine mammal take from 
the proposed 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 proposes to authorize is below one third of 
the estimated stock abundance for all but one species (in fact, take of 
individuals is less than 2 percent of the abundance of the 4 of the 5 
affected stocks, see Tables 8 and 9). This is likely a conservative 
estimate because 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 would count them as separate takes if 
they cannot be individually identified.
    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 
proposed authorized take for harbor seals is 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 
proposed 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 would 
be lower. Lastly, take would occur in a small portion of Tillamook Bay 
and it is unlikely that a third of the stock would be in these waters 
during the short duration of the proposed activities.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds, specific 
to both the Year 1 and Year 2 proposed IHAs, that small numbers of 
marine mammals would 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 would 
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 proposed for 
authorization or expected to result from these activities. Therefore, 
NMFS has determined that formal consultation under section 7 of the ESA 
is not required for this action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue two IHAs to the Corps incidental to conducting repairs of the 
Tillamook South Jetty in Tillamook Bay, Oregon from November 1, 2022 to 
October 31, 2023 (Year 1 IHA) and from November 1, 2024 to October 31, 
2025 (Year 2 IHA), provided the previously mentioned mitigation, 
monitoring, and reporting requirements are incorporated. Drafts of the 
proposed IHAs can be found at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

[[Page 38141]]

Request for Public Comments

    We request comment on our analyses, the proposed authorizations, 
and any other aspect of this notice of proposed IHAs for the proposed 
construction activities. We also request comment on the potential 
renewal of these proposed IHAs as described in the paragraph below. 
Please include with your comments any supporting data or literature 
citations to help inform decisions on the request for these IHAs or a 
subsequent renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, one-year 
renewal IHA following notice to the public providing an additional 15 
days for public comments when (1) up to another year of identical or 
nearly identical activities as described in the Description of Proposed 
Activities section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activities section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
    <bullet> A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
    <bullet> The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    Upon review of the request for renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS determines 
that there are no more than minor changes in the activities, the 
mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: June 21, 2022.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2022-13605 Filed 6-24-22; 8:45 am]
BILLING CODE 3510-22-P


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