Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Army Corps of Engineers Baker Bay Pile Dike Repair Project, 60385-60405 [2024-16367]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 89, Number 143 (Thursday, July 25, 2024)]
[Notices]
[Pages 60385-60405]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-16367]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD995]


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

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from Army Corps of Engineers 
(ACOE) for authorization to take marine mammals incidental to Baker Bay 
Pile Dike Repair Project in Baker Bay, Oregon. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an incidental harassment authorization (IHA) to 
incidentally take marine mammals during the specified activities. NMFS 
is also requesting comments on a possible one-time, 1-year renewal 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 August 
26, 2024.

[[Page 60386]]


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 
[email protected]. 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 below.
    Instructions: NMFS is not responsible for comments sent by any 
other method, 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 https://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: Craig Cockrell, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Background

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

National Environmental Policy Act

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

Summary of Request

    On September 8, 2022, NMFS received a request from the ACOE for an 
IHA to take marine mammals incidental to pile driving and removal at 
the mouth of the Columbia River in Oregon. Following NMFS' review of 
the application, the ACOE submitted two revised versions on March 4, 
2024 and May 1, 2024. The application was deemed adequate and complete 
on June 10, 2024. The ACOE's request is for take of eight species of 
marine mammals by Level B harassment and, for harbor seal (Phoca 
vitulina), Level A harassment. Neither ACOE nor NMFS expect serious 
injury or mortality to result from this activity and, therefore, an IHA 
is appropriate.

Description of Proposed Activity

Overview

    ACOE is planning to conduct pile dike repairs in the Baker Bay 
system, located in the Columbia River estuary. This system of dikes and 
channel markers connect the Mouth of the Columbia River Federal 
navigation channel and the Port of Ilwaco at river mile 3 between jetty 
A and West Sand Island. This pile dyke system is an important for 
controlling the tidal flow and sedimentation in the Federal navigation 
channel to maintain needed depths. Vibratory and impact pile driving 
would introduce underwater sounds that may result in take, by Level A 
and Level B harassment, of marine mammals. It is expected to take up to 
12 non-consecutive days to complete the pile driving activities from 
August through October.

Dates and Duration

    The pile dike repairs are expected to take 3- months to complete 
with in-water work beginning from August 1, 2025 through July 31, 2026. 
No in-water work would be completed from December through June to avoid 
potential impacts to endangered species act (ESA) listed fish species 
and Southern Resident killer whales. It is expected to take up to 12 
non-consecutive days to complete the pile driving activities. Pile 
driving would be completed intermittently throughout daylight hours.

Specific Geographic Region

    The Baker Bay West pile-dike system contains four pile dikes 
(figure 1) and is located immediately adjacent to the Baker Bay West 
Federal navigation channel. The Baker Bay West Federal navigation 
channel comprises two segments; the segment nearest the Columbia River 
is 2,000 feet (ft) (609 meters (m)) long, 200 ft. (61-m) wide, and 
roughly 16 ft. (5 m) deep, and the segment nearest the Port of Ilwaco 
is 2.5 miles (4 kilometers (km)) long, 150 ft. (46-m) wide, and 16 ft. 
deep. The Baker Bay West pile dikes are located in the downstream 
terminus of the Columbia River tidal estuary, which is dominated by 
freshwater inputs from the Columbia and Willamette rivers. This estuary 
stretches from the mouth of the river upstream to Bonneville Dam at 
river mile 146.

[[Page 60387]]

[GRAPHIC] [TIFF OMITTED] TN25JY24.004

Detailed Description of the Specified Activity

Port Access and Staging of Equipment
    The ACOE anticipates that construction contractors will use either 
the Port of Ilwaco or Port of Chinook to access West Sand Island. 
Barges will transport all equipment and material to and from West Sand 
Island and the pile dike. Barges will serve as staging platforms for 
in-water construction and may be spudded (temporary steel shaft to 
ancor a barge) or anchored into position. The proposed access area is 
located between Baker Bay pile dike 0.86 and pile dike 0.70. Staging 
equipment is not expected to result in take of marine mammals and is 
not discussed further.
Material Offloading Facility Construction (Option 1 and Option 2)
    ACOE proposes to construct a material offload facility on West Sand 
Island to offload materials transported by barges. ACOE, and 
subsequently NMFS, analyzed two construction options for the material 
offloading facility, and the construction contractor would select one 
of these two options. Option 1 would require the use of a cofferdam 
constructed with 24-inch (in) (61 centimeters (cm)) steel sheet piles 
that would be set in place with vibratory hammers. Once constructed, 
the cofferdam would be filled with granular structural material to 
support the offloading of material. Approximately 25,000 cubic yards 
(cy) of material would also need to be dredged from the site in order 
to provide sufficient depth for the rock barge to access the cofferdam. 
Once construction is complete, the cofferdam would be deconstructed 
using vibratory hammers to remove the steel sheet piles.
    Option 2 would consist of a two-barge system to offload materials 
on West Sand Island using a transition barge. The contractor would 
first offload materials from the rock barge onto the transition barge 
and, those materials would then be offloaded from the transition barge 
onto West Sand Island The transition barge would be spudded into place 
for the duration of the construction period. Approximately 2,800 cy of 
material would be dredged to provide sufficient depth for rock barges 
to deliver materials to the construction site. ACOE would construct 
four mooring dolphins out of 16 24-in steel pipe piles. These mooring 
dolphins would be used to moor rock barges in an area to offload 
materials onto the transition barge. The 24-in steel pipe piles would 
be driven using vibratory hammers.
    ACOE anticipates that the construction contractor is most likely to 
select Option 2, due to the high cost associated with Option 1. For 
either option selected, vibratory pile driving and removal may result 
in take of marine mammals. While marine mammals may behaviorally 
respond in some small degree to the noise generated by dredging 
operations, given the slow, predictable movements of these vessels, and 
absent any other contextual features that would cause enhanced concern, 
NMFS does not expect ACOE's proposed dredging in either option to 
result in the take of marine mammals.
Dune Reinforcement
    The existing dune along the shoreline at West Sand Island has 
developed a depression near the proposed location of the project area 
that needs to be fortified to protect the morphology of the island. To 
address this risk, ACOE would reinforce the dune by placing material 
(such as brush, root masses, logs, branches, and sand), grubbed from 
the staging area into the low spot. NMFS does not expect this activity 
to result in take of marine mammals due to the activity being conducted 
on land.

[[Page 60388]]

Baker Bay 0.28 Jetty Reinforcement and Repair
    To repair Baker Bay 0.28 Jetty, ACOE would place new rock and 
remove old timber piles. ACOE will place approximately 550 cy of rock 
material on top of existing enrockment to bring the enrockment back to 
elevation 0 at both ends of the Baker Bay 0.28 jetty. Land-based and 
barge-based excavators and/or cranes will place the rock. An equipment 
barge will be moored adjacent to a rock barge.
    For rock placement below the water surface, ACOE would require the 
contractor to place rock from a clamshell, orange peel grab, or 
excavator bucket, and it must not open the bucket for placement until 
the bucket is below the water surface. ACOE will not permit releasing 
rocks from a bucket above the water surface. For rock placement near or 
above the water surface, where opening the bucket below the surface is 
not possible, the contractor must place the bucket as close as safely 
possible to the placement location before opening. NMFS does not expect 
rock placement to result in marine mammal harassment and it is not 
discussed further beyond the explanation provided here. Rock placement 
would occur in a controlled manner, with the rock release occurring 
close to the rock destination which would minimize the sound produced. 
It does not require seafloor penetration, and would not affect habitat 
for marine mammals and their prey beyond that already affected by 
installation the existing Baker Bay 0.28 Jetty.
    During rock placement, ACOE would work closely with the contractor 
to regularly assess subsurface conditions and grades via conditional 
hydrographic surveys, taking corrective actions as necessary. The 
contractor would perform hydrographic and topographic surveys pre-
construction and post-construction to ensure proper rock placement. 
Equipment used to conduct hydrographic and topographic surveys are not 
anticipated to result in take of marine mammals, as any elevated noise 
levels produced through these activities are expected to be high-
frequency, highly-directional, intermittent, and of short duration.
    ACOE will also remove 486 timber piles by pulling, cutting, or 
snapping the pile at the level of enrockment. Noise levels produced by 
these activities are not expected to exceed baseline levels produced by 
other routine sources in the area (e.g., vessel transit), and any 
elevated noise levels produced through these activities are expected to 
be intermittent, of short duration, and with low peak values. 
Therefore, this activity is not expected to result in take of marine 
mammals.
Hazard Pile Marker Installation
    Once the new pile dike systems are completed, the enrockment would 
frequently be just below the surface of the water. This would create a 
shallow water hazard for river users. The ACOE proposes to place 12 
marker piles along the pile dikes in Baker Bay. The maker piles would 
be steel pipe piles and would range in size from 12 in (30 cm) to 24 in 
(60 cm) in diameter. The larger piles would be used in areas where the 
current is stronger. Piles would be driven with either impact or 
vibratory hammers depending on the substrate at the install location.
    Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Vibratory hammers install 
piles by vibrating them and allowing the weight of the hammer to push 
them into the sediment. It is anticipated that half of the piles will 
be driven using impact hammers and half would be driven using vibratory 
hammers. Driving shoes may be used to facilitate driving and reduce 
driving time. NMFS expects that take of marine mammals may occur during 
the use of impact and vibratory hammers during the pile maker 
installation.

                                          Table 1--Number, Size, and Types of Piles To Be Installed and Removed
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                                                           Pipe pile mooring        Pipe pile mooring           Sheet pile
                                 Pile marker install     dolphins install (MOF    dolphins removal (MOF      installation (MOF      Sheet pile removal
                                                               option 2)                option 2)                option 1)            (MOF option 1)
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Pile Diameter size (in)......  24 (steel).............  24 (steel).............  24 (steel).............  24 (steel)............  24 (steel).
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                                                             Vibratory Pile Driving/Removal
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Total Quantity...............  12.....................  16.....................  16.....................  125...................  125.
Max # of Piles per day.......  8......................  8......................  16.....................  25....................  60.
Vibratory time per pile (min)  15.....................  20.....................  5......................  15....................  3.
Number of Days...............  3......................  2......................  1......................  5.....................  3.
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                                                                   Impact Pile Driving
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Total Quantity...............  12.....................  N/A....................  N/A....................  N/A...................  N/A.
Piles per day................  5......................  N/A....................  N/A....................  N/A...................  N/A.
Strikes per pile.............  225....................  N/A....................  N/A....................  N/A...................  N/A.
Number of Days...............  3......................  N/A....................  N/A....................  N/A...................  N/A.
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    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting sections).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and 
more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this activity and summarizes information 
related to the population or stock, including

[[Page 60389]]

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 proposed 
to be authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Pacific SARs. All values presented in table 2 are the most 
recent available at the time of publication (including from the draft 
2023 SARs) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

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

    As indicated above, all eight species (with nine 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 that could 
potentially occur in the proposed project areas are included in table 2 
of the IHA application. While the following 18 marine mammal species 
have been sighted in the area, the temporal and/or spatial occurrence 
of these species is such that take is not expected to occur, and they 
are not discussed further beyond the explanation provided here.
    The spatial, temporal, and overall occurrence of fin whale 
(Balaenoptera physalus), minke whale (Balaenoptera acutorostrata), blue 
whale (Balaenoptera musculus), sei whale (Balaenoptera borealis), 
Pacific white-sided dolphin (Lagenorhynchus obliquidens), Risso's 
dolphin (Grampus griseus), common bottlenose dolphin (Tursiops 
truncatus), striped dolphin (Stenella coeruleoalba), Short-beaked 
common dolphin, (Delphinus delphis), Northern right-whale dolphin 
(Lissodelphis borealis), 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), and Dall's porpoise 
(Phocoenoides dalli) are such that take is not expected to occur. Many 
of these species are either rarely present in the proposed project area 
or typically found in deep offshore waters far from the proposed 
project site.

Gray Whale

    Gray whales in the project area would be of the Eastern North 
Pacific stock.

[[Page 60390]]

During summer and fall, gray whales of the Eastern North Pacific stock 
migrate from breeding grounds off the coast of Baja California and 
Mexico to feeding areas in the Bering Seas.
    Gray whales along the Oregon coastline are typically part of the 
Pacific coast feeding group, and their abundance and residence time in 
Oregon may correlate with the availability of mysids (Holmesimysis 
sculpta), a major prey item (Newell and Cowles 2006). There are few 
recorded sightings of gray whales in the Mouth of the Columbia River. 
In 2021, a mother and calf were spotted just upriver from the proposed 
project sight (K. Tidwell personal communication).

Humpback Whale

    Humpback whales from the Central America/Southern Mexico-CA/OR/WA 
stock and the Mainland Mexico-CA/OR/WA stock are likely to occur in the 
project area in the respective percentages of 42 and 58 percent.
    Humpback whale feeding groups have begun utilizing the Mouth of the 
Columbia River as foraging ground, arriving in the lower Columbia 
estuary as early as mid-June, and have been observed as late as mid-
November with a peak abundance coinciding with the peak abundance of 
forage fish in mid-summer. Humpback whale have been observed in the 
immediate vicinity of West and East Sand Islands in late summer and 
fall of 2015, 2016, 2017, and 2019 (The Columbian 2016; The Columbian 
2019). They were again seen earlier in the season than ever, at the 
beginning of April in 2020 (Chinook Observer, 2020). Recent monitoring 
during the Sand Island Test Pile Project reported one humpback whale in 
the Level B harassment zone during vibratory pile driving. One to two 
Humpback whales were seen on occasion during the project, with all 
other detections occurring outside of the Level B harassment zone or 
while no pile driving was occurring. The whales seemed to come through 
the area with the incoming tides to forage for food and leave with the 
outgoing tides (Hamer Environment L.P. 2020). Based on this 
information, it is possible that humpback whales may pass through and 
may forage intermittently in the proposed project area.

Killer Whale

    The West Coast Transient stock includes animals that range from 
California to southern Alaska and is genetically distinct from both 
resident and other transient populations in the region. It is the only 
killer whale stock that is expected to occur in the project area, and 
occurrence in the mouth of the Columbia River is linked to the Chinook 
salmon run in March and April, although some sightings have occurred in 
the early fall during aerial surveys (Adams, 2014). Southern resident 
killer whales occur in the offshore waters of Washington and Oregon but 
have not been documented entering the mouth of the Columbia River. 
Killer whales were not sighted during the Sand Island Test Pile Project 
(Hamer Environment L.P., 2020).

Harbor Porpoise

    The Northern Oregon/Washington Coast stock of harbor porpoises 
ranges from Lincoln City, OR, to Cape Flattery, WA (Carretta et al. 
2019). Aerial survey data from coastal Oregon and Washington, collected 
during all seasons, suggest that harbor porpoise distribution varies by 
depth (Green et al. 1992). Although distinct seasonal changes in 
abundance along the west coast have been noted and attributed to 
possible shifts in distribution to deeper offshore waters during late 
winter (Dohl et al. 1983, Barlow 1988 cited in NOAA 2014), seasonal 
movement patterns are not fully understood.
    Harbor porpoises are usually found in shallow water, most often 
nearshore, although they occasionally travel over deeper offshore 
waters (NOAA 2013). Most harbor porpoise groups are small, generally 
consisting of less than five or six individuals, though for feeding or 
migration they may aggregate into large, loose groups of 50 to several 
hundred animals (Halpin, OBIS-SEAMAP 2019). Behavior tends to be 
inconspicuous, compared to most dolphins, and they feed by seizing prey 
which consists of wide variety of fish and cephalopods ranging from 
benthic or demersal (Halpern, OBIS-SEAMAP 2019). Harbor porpoises are 
sighted year-round in the mouth of the Columbia River (Griffith 2015). 
Their abundance peaks with the abundance of anchovy presence in the 
river and nearshore. Groups of one to two harbor porpoise were observed 
during pre- and post- monitoring activities of the Sand Island Test 
Pile Project (Hamer Environment L.P. 2020).

Steller Sea Lion

    Steller sea lions forage in nearshore and pelagic waters where they 
are opportunistic predators.
    Large numbers of Steller sea lions use the nearby South Jetty for 
hauling out (Jeffries 2000) and are present, in varying abundances, all 
year. Use occurs chiefly at the concrete block structure at the 
terminus, or head of the jetty. According to Oregon Department of Fish 
and Wildlife (ODFW) (2014), during the summer months it is not uncommon 
to observe between 500 to 1,000 Steller sea lions present per day. More 
frequent surveys by Washington Department of Fish and Wildlife (WDFW) 
for the same time frame (2000-2014) put the monthly range at 177 to 
1,663 animals throughout the year. Steller sea lions are most abundant 
in the vicinity during the winter months and tend to disperse elsewhere 
to rookeries during breeding season between May and July (Corps 2007). 
All population age classes, and both males and females, use the South 
Jetty to haul out. No Steller sea lions were observed during the 
monitoring activities of the Sand Island Test Pile Project (Hamer 
Environment L.P. 2020).

California Sea Lion

    Since the mid-1980s, increasing numbers of California sea lions 
have been documented feeding on fish along the Washington coast and--
more recently--in the Columbia River as far upstream as Bonneville Dam, 
145 mi (233 km) from the river mouth. Large numbers of California sea 
lions (Zalophus californianus) use the nearby South Jetty for hauling 
out (Jeffries 2000). According to ODFW (2014) most California sea lions 
are concentrated near the tip of the South Jetty. California sea lions 
can intermingle with Steller sea lions. As, reported in the ODFW survey 
information (2007 and 2014) indicates that California sea lions are 
relatively less prevalent in the Pacific Northwest during June and 
July, though in the months just before and after their presence there 
can be several hundred using the South Jetty. More frequent WDFW 
surveys (2014) indicate greater numbers in the summer, and use remains 
concentrated to fall and winter months. During pile driving work at the 
Sand Island Test Pile Project in 2020, observers identified 60 
individuals in 55 separate sightings and of those 60, 13 animals were 
observed in the Level B harassment zone (Hamer Environment L.P. 2020).

Harbor Seal

    Harbor seals are one of the most abundant pinnipeds in Oregon and 
typically occur in coastal marine and estuarine waters of the Oregon 
coast throughout the year. On land, they occur on offshore rocks and 
islands, along shore, and on exposed flats in the estuary (Harvey 
1987). They haul out on rocks, reefs, beaches, and drifting glacial ice 
and feed in marine, estuarine, and occasionally fresh waters. Harbor 
seals generally are non-migratory, with local movements associated with 
tides, weather, season, food availability, and reproduction. (Carretta 
et al. 2019).

[[Page 60391]]

During pile driving work at the Sand Island Test Pile Project in 2020, 
observers identified 303 individuals in 209 separate sightings. Of 
those 303 individuals, 2 animals were observed in the Level A 
harassment zone and 106 animals were observed in the Level B harassment 
zone (Hamer Environment L.P. 2020).

Northern Elephant Seal

    The California Breeding Stock of Northern elephant seals breeds and 
gives birth in California but makes extended foraging trips to areas 
including coastal Oregon biannually during the fall and spring. They 
spend about 90 percent of their time at sea underwater, making 
sequential deep dives. 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). Prior to 1984, only two sightings of Northern elephant 
seals were recorded near the project site. One was sighted near Tongue 
Point and another was found dead at river mile 47 (upriver from the 
project site (Jeffries 1984). Since then, they have been seen at the 
mouth of the Columbia River infrequently. None have been observed 
during recent monitoring, but there have been recent sightings upriver 
from the project 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.). 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.

                  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 et al., 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take of Marine Mammals 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 of Marine Mammals 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.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound 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. The sound level of an area is defined by the 
total acoustical energy being generated by known and unknown sources. 
These sources may include physical (e.g., waves, wind, precipitation, 
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced 
by marine mammals, fish, and invertebrates), and anthropogenic sound 
(e.g., vessels, dredging, aircraft, construction).
    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 to 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

[[Page 60392]]

the local environment or could form a distinctive signal that may 
affect marine mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving, and vibratory pile 
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; ANSI 2005; 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 raid rise/decay time that 
impulsive sounds do (ANSI 1995; NIOSH 1998; NMFS 2018). The distinction 
between impulsive and non-impulsive sound sources is important because 
they have differing potential to cause physical effects, particularly 
with regard to hearing (e.g., Ward 1997; Southall et al. 2007).
    Impact hammers operate by repeatedly dropping 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 generally 
produce sound pressure levels (SPLs) 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 Haines Borough's proposed 
activities on marine mammals could be generated by both non-acoustic 
and acoustic stressors. Potential non-acoustic stressors could include 
the physical presence of the equipment and personnel; however, given 
there are no known pinniped haul-out sites in the vicinity of the 
proposed project site, visual and other non-acoustic stressors would be 
limited, and any impacts to marine mammals are expected to primarily be 
acoustic in nature.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving or drilling is the primary means by which 
marine mammals may be harassed from the Haines Borough specified 
activity. 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; Southall et al. 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 or drilling 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. 
mother 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) 
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 (2018a), 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).
    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). PTS does not 
generally affect more than a limited frequency range, and an animal 
that has incurred PTS has incurred some level of hearing loss at the 
relevant frequencies; typically animals with PTS are not functionally 
deaf (Richardson et al., 1995; Au and Hastings, 2008). Available data 
from humans and other terrestrial mammals indicate that a 40-dB 
threshold shift approximates PTS onset (Ward et al. 1958 and 1959; Ward 
1960; Kryter et al. 1966; Miller 1974; Ahroon et al. 1996; Henderson et 
al. 2008). PTS criteria 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)--TTS is 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 (Southall et al. 2007; Southall et al. 2019), 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; Finneran 
et al. 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 Masking, 
below). For example, a marine

[[Page 60393]]

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.
    Many studies have examined noise-induced hearing loss in marine 
mammals (see Finneran (2015) and Southall et al. (2019) for summaries). 
TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter 2013). 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. For 
cetaceans, published data on the onset of TTS are limited to captive 
bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis) (Southall et al., 2019). For pinnipeds in water, 
measurements of TTS are limited to harbor seals, elephant seals 
(Mirounga angustirostris), bearded seals (Erignathus barbatus), and 
California sea lions (Zalophus californianus) (Kastak et al., 1999 and 
2007; Kastelein et al. 2019b and 2019c; Reichmuth et al. 2019; Sills et 
al. 2020; Kastelein et al. 2021; 2022a; and 2022b). These studies 
examine hearing thresholds measured in marine mammals before and after 
exposure to intense or long-duration sound exposures. The difference 
between the pre-exposure and post-exposure thresholds can be used to 
determine the amount of threshold shift at various post-exposure times.
    The amount and onset of TTS depends on the exposure frequency. 
Sounds at low frequencies, well below the region of best sensitivity 
for a species or hearing group, are less hazardous than those at higher 
frequencies, near the region of best sensitivity (Finneran and 
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al. 2019a; 2019c). Note that in general, harbor 
seals and harbor porpoises have a lower TTS onset than other measured 
pinniped or cetacean species (Finneran, 2015). In addition, TTS can 
accumulate across multiple exposures, but the resulting TTS will be 
less than the TTS from a single, continuous exposure with the same SEL 
(Mooney et al. 2009; Finneran et al. 2010; Kastelein et al. 2014; 
2015). This means that TTS predictions based on the total, cumulative 
SEL will overestimate the amount of TTS from intermittent exposures, 
such as sonars and impulsive sources. Nachtigall et al. (2018) and 
Finneran (2018) describe measurements of hearing sensitivity of 
multiple odontocete species (bottlenose dolphin, harbor porpoise, 
beluga, and false killer whale (Pseudorca crassidens) when a relatively 
loud sound was preceded by a warning sound. These captive animals were 
shown to reduce hearing sensitivity when warned of an impending intense 
sound. Based on these experimental observations of captive animals, the 
authors suggest that wild animals may dampen their hearing during 
prolonged exposures or if conditioned to anticipate intense sounds. 
Another study showed that echo-locating animals (including odontocetes) 
might have anatomical specializations that might allow for conditioned 
hearing reduction and filtering of low-frequency ambient noise, 
including increased stiffness and control of middle ear structures and 
placement of inner ear structures (Ketten et al. 2021). Data available 
on noise-induced hearing loss for mysticetes are currently lacking 
(NMFS 2018). Additionally, the existing marine mammal TTS data come 
from a limited number of individuals within these species.
    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 impulsive 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.
    Furthermore, installing piles for this project requires a 
combination of impact pile driving and vibratory pile driving. For the 
project, these activities would not occur at the same time and there 
would likely be pauses in activities producing the sound during each 
day. Given these pauses and that many marine mammals are likely moving 
through the action area and not remaining for extended periods of time, 
the potential for any TS declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal also has the potential to behaviorally disturb marine mammals. 
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; Southall 
et al. 2021). 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; 
Southall et al. 2021).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke 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

[[Page 60394]]

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, Southall et al. 2021; Weilgart 2007; Archer et al. 2010). 
Behavioral reactions can vary not only among individuals but also 
within exposures of an individual, depending on previous experience 
with a sound source, context, and numerous other factors (Ellison et 
al. 2012; Southall et al. 2021), 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. For a review of studies involving marine 
mammal behavioral responses to sound, see: Southall et al. 2007; Gomez 
et al. 2016; and Southall et al. 2021.
    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). 
In addition, behavioral state of the animal plays a role in the type 
and severity of a behavioral response, such as disruption to foraging 
(e.g., Silve et al. 2016; Wensveen et al. 2017). 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.
    In 2020, the Sand Island Test Pile Project (84 FR 61026, November 
12, 2019) documented observations of marine mammals during construction 
activities (i.e., pile driving) on East and West Sand Island. This 
project is in the same area as the proposed project site. During the 
15-days (September-October) of protected species observers documented 
nine humpback whales and eight harbor porpoise were observed feeding 
and traveling. There were 309 harbor seals and 61 California sea lions 
observed during the monitoring period of the project with no behaviors 
recorded during monitoring activities (Hamer Environment L.P. 2020).
    Masking--Sound can disrupt behavior through masking, or interfering 
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). Masking occurs when the 
receipt of a sound is interfered with by another coincident sound at 
similar frequencies and at similar or higher intensity, and may occur 
whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. 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. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked.
    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 pile driving activities. Cetaceans are 
not expected to be exposed to airborne sounds that would result in 
harassment as defined under the MMPA.
    Airborne noise would primarily be an issue for pinnipeds that are 
swimming near the project site within the range of noise levels 
exceeding the acoustic thresholds. 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 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 proposed project would occur within the same footprint as the 
current Baker Bay pile dikes. The nearshore habitat where the proposed 
project would occur is an area of relatively high marine vessel 
traffic. Most marine mammals do not generally use the area within the 
immediate vicinity of the project area. Temporary, intermittent, and 
short-term habitat alteration may result from increased noise levels 
within the Level A and Level B harassment zones. Effects on marine 
mammals will be limited to temporary displacement from pile 
installation and removal noise, and effects on prey species will be 
similarly limited in time and space.
    Water Quality--Temporary and localized reduction in water quality 
will occur as a result of in-water construction activities. Most of 
this effect will occur during the installation and removal of piles 
when bottom sediments are disturbed. The installation and removal of 
piles will disturb bottom sediments and may cause a temporary increase 
in suspended sediment in the project area. During pile extraction, 
sediment attached to the pile moves vertically through the water column 
until gravitational forces cause it to slough off under its own weight. 
The small resulting sediment plume is expected to settle out of the 
water column within a few hours. Studies of the effects of turbid water 
on fish (marine mammal prey) suggest that concentrations of suspended 
sediment can reach thousands of milligrams per liter before an acute 
toxic reaction is expected (Burton 1993).

[[Page 60395]]

    Impacts to water quality would be localized and temporary and would 
have negligible impacts on marine mammal habitat. Effects to turbidity 
and sedimentation are expected to be short-term, minor, and localized. 
Since the currents are strong in the area, following the completion of 
sediment-disturbing activities, suspended sediments in the water column 
should dissipate and quickly return to background levels in all 
construction scenarios. Turbidity within the water column has the 
potential to reduce the level of oxygen in the water and irritate the 
gills of prey fish species in the proposed project area. However, 
turbidity plumes associated with the project would be temporary and 
localized, and fish in the proposed project area would be able to move 
away from and avoid the areas where plumes may occur. Therefore, it is 
expected that the impacts on prey fish species from turbidity, and 
therefore on marine mammals, would be minimal and temporary. In 
general, the area likely impacted by the proposed construction 
activities is relatively small compared to the available marine mammal 
habitat in the mouth of the Columbia River and surrounding coastal 
waters.

Effects on Prey

    Construction activities would produce continuous (i.e., vibratory 
pile driving) and impulsive (i.e., impact driving) sounds. 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. 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, although several are based on studies 
in support of large, multiyear bridge construction projects (e.g., 
Scholik and Yan 2001, Scholik and Yan 2002; Popper and Hastings 2009). 
Sound pulses at received levels may cause noticeable changes in 
behavior (Pearson et al. 1992; Skalski et al. 1992). SPLs of sufficient 
strength have been known to cause injury to fish and fish mortality.
    Impacts on marine mammal prey (i.e., fish or invertebrates) of the 
immediate area due to the acoustic disturbance are possible. The 
duration of fish or invertebrate avoidance or other disruption of 
behavioral patterns in this area after pile driving stops is unknown, 
but a rapid return to normal recruitment, distribution and behavior is 
anticipated. Further, significantly large areas of fish and marine 
mammal foraging habitat are available in the nearby vicinity in the 
mouth of the Columbia River.
    The duration of the construction activities is relatively short, 
with pile driving and removal activities expected last less than 1-
year. Each day, construction would occur for no more than 12 hours 
during the day and pile driving activities would be restricted to 
daylight hours. The most likely impact to fish from pile driving 
activities at the project area would be temporary behavioral avoidance 
of the area. In general, impacts to marine mammal prey species are 
expected to be minor and temporary due to the short timeframe for the 
project.
    Construction activities, in the form of increased turbidity, have 
the potential to adversely affect fish in the project area. Increased 
turbidity is expected to occur in the immediate vicinity (on the order 
of 10 ft (3 m) or less) of construction activities. However, suspended 
sediments and particulates are expected to dissipate quickly within a 
single tidal cycle. Given the limited area affected and high tidal 
dilution rates any effects on fish are expected to be minor or 
negligible. In addition, best management practices would be in effect, 
which would limit the extent of turbidity to the immediate project 
area.
    The area likely impacted by the project is relatively small 
compared to the available habitat in the surrounding waters of the 
mouth of the Columbia River.
    In summary, given the relatively short daily duration of sound 
associated with individual pile driving and events and the relatively 
small areas being affected, 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. 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 of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through the IHA, which will inform NMFS' 
consideration of ``small numbers,'' the negligible impact 
determinations, and impacts on subsistence uses.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of the construction equipment (i.e., pile driving) has the potential to 
result in disruption of behavioral patterns for individual marine 
mammals. There is also some potential for auditory injury (Level A 
harassment) of phocids because predicted auditory injury zones are 
larger than for other species. The 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.

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

[[Page 60396]]

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. 
Generally speaking, Level B harassment take estimates based on these 
behavioral harassment thresholds are expected to include any likely 
takes by TTS as, in most cases, the likelihood of TTS occurs at 
distances from the source less than those at which behavioral 
harassment is likely. TTS of a sufficient degree can manifest as 
behavioral harassment, as reduced hearing sensitivity and the potential 
reduced opportunities to detect important signals (conspecific 
communication, predators, prey) may result in changes in behavior 
patterns that would not otherwise occur.
    The ACOE's proposed construction includes the use of continuous 
(vibratory pile driving) and impulsive (impact pile driving) sources, 
and therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa are 
applicable.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0; 
Technical Guidance 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). The ACOE's 
proposed construction includes the use of impulsive (impact pile 
driving) and non-impulsive (vibratory pile driving) sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

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

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., impact pile driving and 
vibratory pile driving and removal). The maximum (underwater) area 
ensonified above the thresholds for behavioral harassment referenced 
above is 20.72 km\2\ (12.87 mi\2\), and would consist of most of the 
mouth of the Columbia River immediately south of West Sand Island 
(figure 2). Additionally, vessel traffic in the project area may 
contribute to elevated background noise levels which may mask sounds 
produced by the project.

[[Page 60397]]

[GRAPHIC] [TIFF OMITTED] TN25JY24.005

    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B x Log10 (R1/R2),

where

TL = transmission loss in dB
B = transmission loss coefficient
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. Spherical spreading occurs in a perfectly unobstructed 
(free-field) environment not limited by depth or water surface, 
resulting in a 6-dB reduction in sound level for each doubling of 
distance from the source (20*log[range]). Cylindrical spreading occurs 
in an environment in which sound propagation is bounded by the water 
surface and sea bottom, resulting in a reduction of 3 dB in sound level 
for each doubling of distance from the source (10*log[range]). A 
practical spreading value of 15 is often used under conditions, such as 
the project site, where water increases with depth as the receiver 
moves away from the shoreline, resulting in an expected propagation 
environment that would lie between spherical and cylindrical spreading 
loss conditions. Practical spreading loss is assumed here.
    The intensity of pile driving sounds is greatly influenced by 
factors such as the type of piles, hammers, and the physical 
environment in which the activity takes place. In order to calculate 
the distances to the Level A harassment and the Level B harassment 
sound thresholds for the methods and piles being used in this project, 
the applicant and NMFS used acoustic monitoring data from other 
locations to develop proxy source levels for the various pile types, 
sizes and methods. The project includes vibratory and impact pile 
installation of steel pipe and sheet piles and vibratory removal of 
steel sheet piles. Source levels for 24 in steel pipe piles are used as 
a proxy for all steel piles that may be placed for marker piles of the 
dike system, though smaller piles may be used during the construction. 
NMFS consulted multiple sources to determine valid proxy source levels 
for the impact installation of sheet piles, as indicated in Table 5. 
This is the best available data for sheet pile source levels and is 
based on 24-in sheet piles used for a project in California. Source 
levels for each pile size and driving method are presented in table 5.

[[Page 60398]]



                      Table 5--Proxy Sound Source Levels for Pile Sizes and Driving Methods
----------------------------------------------------------------------------------------------------------------
                                                         Proxy source level (at 10 m)
                                              --------------------------------------------------    Literature
          Pile size                Method         dB RMS re        dB SEL re       dB peak re         source
                                                 1[micro]Pa    1[micro]Pa\2\sec    1[micro]Pa
----------------------------------------------------------------------------------------------------------------
24-in.......................  Vibratory......             154              N/A              N/A  Navy 2015.
24-in sheet pile............  Vibratory......             160              N/A              N/A  Caltrans 2020.
24-in.......................  Impact.........             189              178              203  Caltrans 2015.
----------------------------------------------------------------------------------------------------------------

    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the Technical Guidance that can be used 
to relatively simply predict an isopleth distance for use in 
conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources such as impact or vibratory, the optional User 
Spreadsheet tool predicts the distance at which, if a marine mammal 
remained at that distance for the duration of the activity, it would be 
expected to incur PTS. Inputs used in the optional User Spreadsheet 
tool are reported below (table 6). The resulting estimated Level A 
harassment isopleths and the Level B harassment isopleths are reported 
in table 7.

                  Table 6--User Spreadsheet Inputs for Calculating Level A Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                     Weighting
  Pile size and installation     Spreadsheet tab      factor         Number of       Number of       Activity
            method                    used          adjustment      strikes per    piles per day     duration
                                                       (kHz)           pile                          (minutes)
----------------------------------------------------------------------------------------------------------------
24-in vibratory installation    A.1 Vibratory                2.5             N/A               8              20
 (MOF Option 2).                 pile driving.
24-in vibratory removal (MOF    A.1 Vibratory                2.5             N/A              16               5
 Option 2).                      pile driving.
24-in sheet pile vibratory      A.1 Vibratory                2.5             N/A              25              15
 installation (MOF Option 1).    pile driving.
24-in sheet pile vibratory      A.1 Vibratory                2.5             N/A              60               3
 removal (MOF Option 1).         pile driving.
24-in vibratory installation    A.1 Vibratory                2.5             N/A               8              15
 (Pile Markers).                 pile driving.
24-in impact installation       E.1 Impact pile                2             225               5             N/A
 (Pile Markers).                 driving.
----------------------------------------------------------------------------------------------------------------


                                              Table 7--Calculated Level A and Level B Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    Level A harassment zone (m)                               Level B
                        Activity                         --------------------------------------------------------------------------------   harassment
                                                           LF-cetaceans    MF-cetaceans    HF-cetaceans       Phocids        Otariids        zone (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Pipe Pile Vibratory Install (MOF Option 2)..             4.5             0.4             6.6             2.7             0.2         1,847.8
24-in Steel Pipe Pile Vibratory Removal (MOF Option 2)..             2.8             0.3             4.2             1.7             0.1
24-in sheet pile vibratory installation (MOF Option 1)..            23.4             2.1            34.6            14.2             1.0         4,641.1
24-in sheet pile vibratory removal (MOF Option 1).......            12.2             1.1              18             7.4             0.5
24-in vibratory installation (Pile Markers).............             3.7             0.3             5.5             2.3             0.2         1,847.8
24-in impact installation (Pile Markers)................           501.4            17.8           597.2           268.3            19.5           857.7
--------------------------------------------------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations. We describe how the information 
provided is synthesized to produce a quantitative estimate of the take 
that is reasonably likely to occur and proposed for authorization.
    When available, peer-reviewed scientific publications were used to 
estimate marine mammal abundance in the project area. Data from 
monitoring reports from the previous Sand Island Test Pile Project was 
used to calculate take for several species. However, scientific surveys 
and resulting data, such as population estimates, densities, and other 
quantitative information, are lacking for some species. The ACOE also 
gathered qualitative information from discussions with knowledgeable 
local people that frequent the mouth of the Columbia River. Assumptions

[[Page 60399]]

regarding the size of expected groups of different species, and the 
frequency of occurrence of those groups, were proposed by the ACOE on 
the basis of the aforementioned information and are described for each 
species below.
    Since reliable densities are not available, the take numbers are 
based on the assumed occurrence of a given stock during the activity. 
The applicant used equation 1, below, to estimate take of killer whales 
and Steller sea lions, equation 2 to estimate take of humpback whale, 
harbor porpoise, California sea lions, and harbor seals, and neither 
equation for gray whale or Northern elephant seals. NMFS concurs with 
this method. The estimated take calculation for these/this species is 
explained in the relevant section below.
    (1) Estimated Take = number of individuals in a group x groups per 
day x days of pile-related activity
    (2) Estimated Take = total expected duration of the proposed 
project (minutes) / total duration of the Sand Island Test Pile Project 
x the total number of animals of a given species observed during the 
Sand Island Test Pile Project

Gray Whale

    Historically gray whales have not frequented the mouth of the 
Columbia River. No gray whales were observed during monitoring 
activities of the Sand Island Test Pile Project (Hamer Environment L.P. 
2020). In August of 2020, an ACOE biologist observed two gray whales 
traveling upriver from the project site. Given this recent sighting and 
the temporal overlap of the project and the most recent sighting, NMFS 
proposes to authorize two takes of gray whales by the Level B 
harassment.
    The largest Level A harassment zone for gray whales extends 513 m 
from the noise source (table 7). ACOE is planning to implement shutdown 
zones for low-frequency cetaceans that exceed the Level A harassment 
isopleth for all activities. Therefore, especially in combination with 
the already low occurrence of gray whales in the area, implementation 
of the proposed shutdown zones is expected to eliminate the potential 
for take by Level A harassment of gray whale. Therefore, no take by 
Level A harassment is anticipated or proposed for authorization for 
humpback whales.

Humpback Whales

    Humpback whales have occurred in the lower Columbia River near the 
proposed project area in recent years. Feeding groups have been using 
the mouth of the Columbia River as a foraging ground, arriving as early 
as mid-June, and have been observed as late as mid-November with a peak 
of abundance coinciding with the peak abundance of forage fish in mid-
summer (The Columbian 2019). During pile driving activities of the Sand 
Island Test Pile Project, seven animals were observed (Hamer 
Environment L.P. 2020). The ACOE estimated take of humpback whales 
using equation 2 above resulting in a take estimate of 16 takes by 
Level B harassment (2277 (pile driving minutes for this activity)/1037 
(pile driving minutes for Sand Island Test Pile Project) x 7 observed 
animals). NMFS agrees with this approach and estimated take. As 
described above, NMFS anticipates that 42 percent of takes would occur 
to individuals of the Central America/Southern Mexico-CA/OR/WA stock 
and 58 percent of takes would occur to individuals of the Mainland 
Mexico-CA/OR/WA which would equate to seven and nine takes 
respectively.
    The largest Level A harassment zone for humpback whales extends 513 
m from the noise source (table 7). ACOE is planning to implement 
shutdown zones for low-frequency cetaceans that exceed the Level A 
harassment isopleth for all activities. Implementation of the proposed 
shutdown zones is expected to eliminate the potential for take by Level 
A harassment of humpback whale. No take by Level A harassment is 
anticipated or proposed for authorization for humpback whales.

Killer Whale

    Use of the mouth of the Columbia River is rare for killer whales, 
but in recent years pods of killer whales have been observed in and 
around the mouth of the Columbia River. During the recent monitoring of 
the Sand Island Test Pile Project, no killer whales were observed 
(Hamer Environment L.P. 2020). Aerial seabird marine mammal surveys 
observed 0 killer whales in January 2011, 0 in February 2012, and 10 in 
September 2012 within an approximately 1,500 km2 range near the MCR 
(Adams 2014). A pod of transient killer whales was detected near the 
Astoria Bridge in May of 2018 (Frankowicz 2018) and in 2022 (Tomlinson 
2022). The ACOE estimated the average group sizes from these past 
observations was seven. Based on the rare occurrence of killer whales 
in the project area, ACOE expects that one group of seven killer whales 
may occur during the 12 days of construction in the Level B harassment 
zone. NMFS concurs and is proposing to authorize 7 takes of killer 
whale by Level B harassment.
    The largest Level A harassment zone for killer whales extends 17.8 
m from the noise source (table 7). ACOE is planning to implement 
shutdown zones for mid-frequency cetaceans that exceed the Level A 
harassment isopleth for all activities. Implementation of the proposed 
shutdown zones is expected to eliminate the potential for take by Level 
A harassment of killer whale. No take by Level A harassment is 
anticipated or proposed for authorization for killer whales.

Harbor Porpoise

    Harbor porpoises are regularly observed in the offshore waters near 
the mouth of the Columbia River and are known to occur there year-
round. Porpoise abundance peaks when anchovy (Engraulis mordax) 
abundance in the river and nearshore are highest, which is usually 
between April and August (Litz et al. 2008). Harbor porpoise tend to 
occur in groups of one to two individuals. During the recent monitoring 
of the Sand Island Test Pile Project, eight harbor porpoise were 
observed during construction activities (Hamer Environment L.P. 2020). 
Using equation 2 above, ACOE expects that take by Level B harassment of 
18 animals would occur over the 12 days of pile driving (2277 (pile 
driving minutes for this activity)/1037 (pile driving minutes for Sand 
Island Test Pile Project) x 8 observed animals). NMFS agrees with this 
approach and estimated take.
    The largest Level A harassment zone for harbor porpoise extends 597 
m from the noise source (table 7). ACOE is planning to implement 
shutdown zones for high-frequency cetaceans that exceed the Level A 
harassment isopleth for all activities, and it did not request take by 
Level A harassment of harbor porpoise. For some activities (i.e., 
impact driving of 24-in piles), the shutdown zones extends farther than 
Protected Species Observers (PSO) may be able to reliably detect harbor 
porpoise. However, given the portion of the zone within which PSOs 
could reliably detect a harbor porpoise, the infrequency of harbor 
porpoise observations during the Sand Island Test Pile project 
monitoring, and harbor porpoise sensitivity to noise, no take by Level 
A harassment is anticipated or proposed for authorization for harbor 
porpoise.

Steller Sea Lion

    Steller sea lion occurrence was estimated using WDFW survey 
information haulout information from the South Jetty at the mouth of 
the Columbia River from 2000 to 2014. During the recent monitoring of 
the

[[Page 60400]]

Sand Island Test Pile Project no Steller sea lions were observed (Hamer 
Environment L.P. 2020). Given the close proximity of the haulout it is 
expect that Steller sea lions could occur near the project site. 
Occurrence was estimated using the monthly haulout numbers for the 
months when work would be occurring during the proposed project. In 
August the average number of Steller sea lions hauled out at the jetty 
was 72 and in October the average number of sea lions at the jetty was 
77. In August construction would occur over 7-days and in October 
construction would occur over 5 days. Given the daily occurrence rates 
and days of in-water construction, and using equation 1, the ACOE 
expects that 889 takes by Level B harassment would occur (daily 
occurance (72 or 77) x days of activity), and NMFS proposes to 
authorize 889 takes by Level B harassment of Steller sea lion.
    The largest Level A harassment zone for Steller sea lions extends 
19.5 m from the noise source (table 7). ACOE is planning to implement 
shutdown zones for otariids that exceed the Level A harassment isopleth 
for all activities. Implementation of the proposed shutdown zones is 
expected to eliminate the potential for take by Level A harassment of 
Steller sea lion. No take by Level A harassment is anticipated or 
proposed for authorization for Steller sea lion.

California Sea Lion

    Similar to Steller sea lions, California sea lions use the South 
Jetty at the mouth of the Columbia River and make frequent trips inside 
the mouth of the river. Occurrence on the South Jetty peaks in summer 
and use in the fall and winter is more concentrated. During recent 
monitoring activities of the Sand Island Test Pile Project 59 animals 
were observed (Hamer Environment L.P. 2020). Using equation 2 above, 
ACOE expects that 144 takes by Level B harassment California sea lions 
would occur (2277 (pile driving minutes for this activity)/1037 (pile 
driving minutes for Sand Island Test Pile Project) x 59 observed 
animals), and NMFS proposes to authorize 144 takes by Level B 
harassment of California sea lion.
    The largest Level A harassment zone for California sea lions 
extends 19.5 m from the noise source (table 7). ACOE is planning to 
implement shutdown zones for otariids that exceed the Level A 
harassment isopleth for all activities. Implementation of the proposed 
shutdown zones is expected to eliminate the potential for take by Level 
A harassment of California sea lion. No take by Level A harassment is 
anticipated or proposed for authorization for California sea lion.

Harbor Seal

    Harbor seals are the most abundant pinniped in Oregon and occur in 
the proposed project are year-round. Large numbers of harbor seals move 
through the mouth of the Columbia River throughout the year and are 
expected to be present in the proposed project area. During recent 
monitoring of the Sand Island Test Pile Project, a total of 309 harbor 
seals were observed during construction activities (Hamer Environment 
L.P. 2020). Take estimates were generated using equation 2 above and 
the Sand Island Pile Test Project monitoring results. ACOE expects that 
679 takes by Level B harassment of harbor seals would occur during the 
proposed project (2277 (pile driving minutes for this activity)/1037 
(pile driving minutes for Sand Island Test Pile Project) x 309 observed 
animals), and NMFS proposes to authorize 679 takes by Level B 
harassment of harbor seal.
    The Level A harassment zone for harbor seals during impact 
installation is 268 m (table 7). ACOE would implement a shutdown zone 
of 150 m given the difficulty of observing harbor seals at greater 
distances and practicability concerns regarding efficient work 
production rates that would be associated with a larger shutdown zone 
(see Proposed Mitigation section). During impact installation ACOE 
expects that two harbor seals could be present in the Level A 
harassment zone. Therefore, over the three days of impact pile driving, 
NMFS anticipates, and proposes to authorize, 6 takes by Level A 
harassment (2 takes per day * 3 days = 6 takes by Level B harassment).

Northern Elephant Seal

    Northern elephant seals occur infrequently in the mouth of the 
Columbia River. Recent sightings of elephant seals have occurred in the 
fall and spring upriver from the proposed project site. Although, no 
Northern elephant seals were observed during the Sand Island Test Pile 
Project (Hamer Environment L.P. 2020). ACOE expects that two animals 
may be present in the Level B harassment zone during the 12-days of 
construction, and NMFS proposes to authorize 2 takes by Level B 
harassment of elephant seal.
    The largest Level A harassment zone for Northern elephant seals 
extends 268 m from the noise source (table 7). ACOE is planning to 
implement shutdown zones for Northern elephant seal that exceed the 
Level A harassment isopleth for all activities. Implementation of the 
proposed shutdown zones is expected to eliminate the potential for take 
by Level A harassment of Northern elephant seal. No take by Level A 
harassment is anticipated or proposed for authorization for Northern 
elephant seals.

                                     Table 8--Estimated Take by Level A and Level B Harassment, by Species and Stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                   Total       Proposed
                   Common name                                   Stock                     Stock        Level A      Level B      proposed    take as a
                                                                                       abundance \a\                                take      percentage
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray Whale......................................  Eastern N Pacific.................          26,960            0            2            2           <1
Humpback Whale..................................  Central America/Southern Mexico--            1,494            0            7            7           <1
                                                   CA/OR/WA.
                                                  Mainland Mexico--CA/OR/WA.........           3,477            0            9            9           <1
Killer Whale....................................  West Coast Transients.............             349            0            7            7            2
Harbor Porpoise.................................  Northern OR/WA Coast..............          22,074            0           18           18           <1
Steller sea lion................................  Eastern...........................          36,308            0          889          889          2.4
California Sea Lion.............................  United States.....................         257,074            0          144          144           <1
Harbor Seal.....................................  OR/WA Coastal.....................             UKN            6          679          685          N/A
Northern Elephant Seal..........................  CA Breeding.......................         187,386            0            2            2           <1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Stock size is Nbest according to NMFS 2022 Final Stock Assessment Reports.


[[Page 60401]]

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. NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations.
    The following measures would apply to the ACOE mitigation 
requirements:
    Implementation of Shutdown Zones--For all pile driving/removal 
activities, the ACOE would implement shutdowns within designated zones. 
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). 
Implementation of shutdowns would be used to avoid or minimize 
incidental Level A harassment takes from vibratory and impact pile 
driving and removal (table 9). For all pile driving/removal activities, 
a minimum 25-m shutdown zone would be established for pinnipeds and 50-
m shutdown zone for cetaceans as outlined in the ACOE application for 
an IHA. For harbor seals, ACOE proposed a shutdown zone of 25 m given 
its concerns about potential frequent shutdowns that may occur with a 
larger shutdown zone in consideration of high occurrence of harbor 
seals in the project area. To minimize the potential of Level A 
harassment of harbor seals, NMFS recommended a shutdown zone of 150 m 
for harbor seals. ACOE concurred that this zone was practicable, and 
therefore, NMFS proposes to require a shutdown zone of 150 m for harbor 
seals. Shutdown zones for impact pile driving are based on the Level A 
harassment zones and therefore vary by marine mammal hearing group 
(table 9). The placement of PSOs during all pile driving activities 
(described in detail in the Monitoring and Reporting section) would 
ensure the full extent of shutdown zones are visible to PSOs.

                                              Table 9--Shutdown Zones During Pile Installation and Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                         Shutdown zones (m)
                                                                           -----------------------------------------------------------------------------
                  Activity                             Pile size                                                                  Northern
                                                                                 LF           MF           HF         Harbor      elephant     Otariids
                                                                             cetaceans    cetaceans    cetaceans      Seals         seal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation.....................  24-in (pile markers).........           50           50           50           25           25           25
Vibratory Installation and removal.........  24-in (MOF option 2).........           50           50           50           25           25           25
Vibratory Installation and removal.........  24-in sheet pile (MOF option            50           50           50           25           25           25
                                              1).
Impact Installation........................  24-in (pile markers).........          510           50          600          150          270           25
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Monitoring for Level A and Level B harassment--The ACOE has 
identified monitoring zones correlated with the Level B harassment 
zones. Monitoring zones provide utility for observing by establishing 
monitoring protocols for areas adjacent to the shutdown zones. 
Monitoring zones enable observers to be aware of and communicate the 
presence of marine mammals in the project area outside the shutdown 
zone and thus prepare for a potential cessation of activity should the 
animal enter the shutdown zone. PSOs would monitor the entire visible 
area to maintain the best sense of where animals are moving relative to 
the zone boundaries defined in table 9. Placement of PSOs on the 
shorelines around Sand Island would allow PSOs to observe marine 
mammals near the project area. While not required by this IHA, ACOE 
states that it may also place a PSO on a skiff near the project area if 
safe conditions allow.
    Soft Start--Soft-start procedures are used to provide additional 
protection to marine mammals by providing warning and/or giving marine 
mammals a chance to leave the area prior to the hammer operating at 
full capacity. For impact pile driving, contractors would be required 
to provide an initial set of three strikes at reduced energy, followed 
by a 30-second waiting period, then two subsequent reduced-energy 
strike sets. Soft start would be implemented at the start of each day's 
impact pile driving and at any time following cessation of impact pile 
driving for a period of 30 minutes or longer. Soft start is not 
required during vibratory pile driving and removal activities.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving/removal of 
30 minutes or longer occurs, PSOs would observe the shutdown and 
monitoring zones for a period of 30 minutes. The shutdown zone would be 
considered cleared when a marine mammal has not been observed within 
the zone for that 30-minute period. If a marine mammal is observed 
within the shutdown zone, a soft-start cannot proceed until the animal 
has left the zone or has not been observed for 15 minutes. If the 
monitoring zone has been observed for 30 minutes and marine mammals are 
not present within the zone, soft-start procedures can commence and 
work can continue. Pre-start clearance monitoring must be conducted 
during periods of visibility sufficient for the lead PSO to determine 
that the shutdown zones, indicated in table 9, are clear of marine 
mammals. When a marine mammal for which take by Level

[[Page 60402]]

B harassment is authorized is present in the Level B harassment zone, 
activities may begin. If work ceases for more than 30 minutes, the pre-
activity monitoring of both the monitoring zone and shutdown zone would 
commence.
    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:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.

Visual Monitoring

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

Reporting

    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. It

[[Page 60403]]

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

Reporting Injured or Dead Marine Mammals

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

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the majority of our analysis applies to all 
the species listed in table 8, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, they are described independently in the analysis below.
    Pile driving and removal activities associated with the project as 
outlined previously, have the potential to disturb or displace marine 
mammals. Specifically, the specified activities may result in take, in 
the form of Level A harassment and Level B harassment from underwater 
sounds generated from pile driving and removal. Potential takes could 
occur if individuals of these species are present in zones ensonified 
above the thresholds for Level A or Level B harassment identified above 
when these activities are underway.
    Take by Level A and Level B harassment would be due to potential 
behavioral disturbance, TTS, and PTS. No serious injury or mortality is 
anticipated or proposed for authorization given the nature of the 
activity and measures designed to minimize the possibility of injury to 
marine mammals. Take by Level A harassment is only anticipated for 
harbor seals. The potential for harassment is minimized through the 
construction method (i.e., use of direct pull removal or vibratory 
methods to the extent practical) and the implementation of the proposed 
mitigation measures (see Proposed Mitigation section).
    Behavioral responses of marine mammals to pile driving and removal 
at the project site, if any, are expected to be mild and temporary. 
Marine mammals within the Level B harassment zone may not show any 
visual cues they are disturbed by activities or could become alert, 
avoid

[[Page 60404]]

the area, leave the area, or display other mild responses that are not 
observable such as changes in vocalization patterns. Given the limited 
number of piles to be installed or extracted per day and that pile 
driving and removal would occur across a maximum of 12 days within the 
12-month authorization period, any harassment would be temporary.
    In addition to the expected effects resulting from Level B 
harassment, we anticipate that harbor seals may sustain some limited 
Level A harassment in the form of PTS. However, any PTS is expected to 
be of a small degree (i.e., minor degradation of hearing capabilities 
within regions of hearing that align most completely with the energy 
produced by pile driving (below 2 kHz)) because animals would need to 
be exposed to higher levels and/or longer duration than are expected to 
occur here in order to incur any more than a small degree of PTS. If 
hearing impairment occurs, it is most likely that the affected animal 
would lose a few decibels in its hearing sensitivity, which in most 
cases is not likely to meaningfully affect its ability to forage and 
communicate with conspecifics, as it would be minor and not in the 
region of greatest hearing sensitivity.
    Additionally, and as noted previously, some subset of the 
individuals that are behaviorally harassed could also simultaneously 
incur some small degree of TTS for a short duration of time. Because of 
the small degree anticipated, though, any PTS or TTS potentially 
incurred here would not be expected to adversely impact individual 
fitness, let alone annual rates of recruitment or survival.
    The project also is not expected to have significant adverse 
effects on affected marine mammals' habitat. The project activities 
would not modify existing marine mammal habitat for a significant 
amount of time. The activities may cause some fish or invertebrates to 
leave the area of disturbance, thus temporarily impacting marine 
mammals' foraging opportunities in a limited portion of the foraging 
range; but, because of the short duration of the activities, the 
relatively small area of the habitat that may be affected, and the 
availability of nearby habitat of similar or higher value, the impacts 
to marine mammal habitat are not expected to cause significant or long-
term negative consequences.
    A large portion of the west coast, including the mouth of the 
Columbia River, has been identified as a biologically important area 
(BIA) for gray whale feeding (Calambokidis et al. 2024). As described 
above, the presence of gray whales in the project area is rare, and the 
area of overlap of the project with the feeding BIA affected is small 
compared to the overall size of the BIA. The gray whale feeding BIA is 
active from June through November while the proposed project is 
scheduled to occur between August and October, resulting in only three 
months of overlap with the project and 3 months when the BIA is active 
but ACOE would not be conducting work. Additionally, pile driving 
associated with the project is expected to take only 12 days, further 
reducing the temporal overlap with the BIA. Therefore, take of gray 
whales using this feeding BIA, given both the small footprint of the 
activity relative to the BIA, and the scope and nature of the 
anticipated impacts of pile driving exposure, is not anticipated to 
impact the reproduction or survival of any individuals.
    In summary and as described above, the following factors primarily 
support our 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:
     No serious injury or mortality is anticipated or proposed 
for authorization;
     Any take by Level A harassment (harbor seals, only) is 
anticipated to result in slight PTS within the lower frequencies 
associated with pile driving;
     The anticipated incidents of Level B harassment would 
consist of, at worst, temporary modifications in behavior that would 
not result in fitness impacts to individuals;
     The area impacted by the specified activity is very small 
relative to the overall habitat ranges of all stocks, and does not 
overlap ESA-designated critical habitat. While impacts would occur 
within an area that is important for gray whale feeding, because of the 
small footprint of the activity relative to the feeding area, the 
limited temporal overlap of the activity and the feeding period, and 
the scope and nature of the anticipated impacts of pile driving 
exposure, we do not expect impacts to the reproduction or survival of 
any individuals; and
     ACOE would implement mitigation measures, such as soft-
starts for impact pile driving and shut downs to minimize the numbers 
of marine mammals exposed to injurious levels of sound, and to ensure 
that take by Level A harassment, is at most, a small degree of PTS.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds 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 previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    Table 8 demonstrates the number of animals that NMFS anticipates 
could be taken by Level A and Level B harassment for the proposed work. 
Our analysis shows that at most 2.4 percent of each affected stock 
could be taken by harassment. The numbers of animals proposed to be 
taken for these stocks would be considered small relative to the 
relevant stock's abundances, even if each estimated taking occurred to 
a new individual, which is an unlikely scenario.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals would be taken relative to the population 
size of the affected species or stocks.

Endangered Species Act

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

[[Page 60405]]

for endangered or threatened species, in this case with the West Coast 
region.
    NMFS is proposing to authorize take of Central America/Southern 
Mexico--CA/OR/WA and Mainland Mexico--CA/OR/WA humpback whales, which 
are listed under the ESA. The Permits and Conservation Division has 
requested initiation of section 7 consultation with the West Coast 
Region for the issuance of this IHA. NMFS will conclude the ESA 
consultation prior to reaching a determination regarding the proposed 
issuance of the authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the ACOE for conducting pile installation and removal, 
in Baker Bay, between August 1, 2025 and July 31, 2026, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. A draft of the proposed IHA can be found at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed 
action. We also request comment on the potential renewal of this 
proposed IHA 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 this IHA 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 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity 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:
     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 1-year from expiration 
of the initial IHA).
     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: July 22, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-16367 Filed 7-24-24; 8:45 am]
BILLING CODE 3510-22-P