Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Sand Island Pile Dike System Test Piles Project Near the Mouth of the Columbia River, 38227-38247 [2019-16706]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 84, Number 151 (Tuesday, August 6, 2019)]
[Notices]
[Pages 38227-38247]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-16706]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG910


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Sand Island Pile Dike System 
Test Piles Project Near the Mouth of the Columbia River

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 U.S. Army Corps of Engineers, 
Portland District (Corps) for authorization to take marine mammals 
incidental to the Sand Island Pile Dike System Test Piles project near 
the Mouth of the Columbia River. 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-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 authorizations and agency responses will 
be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than 
September 5, 2019.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent to [email protected].
    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 received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. 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: Rob Pauline, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-
marine-mammal-protection-act. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are issued or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization may be 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 such species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of such takings are set forth.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to potential impacts 
on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (incidental harassment authorizations with 
no anticipated serious injury or mortality) of the Companion Manual for 
NOAA Administrative Order 216-6A, which do not individually or 
cumulatively have the potential for significant impacts on the quality 
of the human environment and for which we have not identified any 
extraordinary circumstances that would preclude this categorical 
exclusion. Accordingly, NMFS has preliminarily determined that the 
issuance of the proposed 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 March 6, 2019, NMFS received a request from the Corps for an IHA 
to take marine mammals incidental to pile driving activities in the 
Columbia River Estuary. The application was deemed adequate and 
complete on June 20, 2019. The Corps' request is for take of a small 
number of harbor porpoises

[[Page 38228]]

(Phocoena phocoena), Steller sea lions (Eumetopias jubatus), California 
sea lions (Zalophus californianus), and harbor seals (Phoca vitulina 
richardii) by Level B harassment and Level A harassment. Neither the 
Corps nor NMFS expect serious injury or mortality to result from this 
activity and, therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    The Corps is proposing to drive test piles in order to investigate 
the feasibility of different construction methods at two of the four 
Sand Island pile dikes at the Mouth of the Columbia River (MCR) (Figure 
1 in application). The Sand Island pile dikes are comprised of four 
pile dikes, which are named according to river mile (RM) location, at 
RMs 4.01, 4.47, 5.15, and 6.37 (the pile dike at RM 6.37 is also 
referred to as the Chinook pile dike). Three of the pile dikes are 
connected to West Sand Island and East Sand Island, and the fourth pile 
dike in open water runs parallel to the Chinook Channel on the upstream 
side (Figure 2 in application). The Sand Island pile dikes are part of 
the Columbia River pile dike system and were installed in the 1930's. 
The Corps intends to restore full functionality of pile dikes in the 
future but needs to drive test piles in order to inform possible 
design. The existing pile dikes have deteriorated greatly due to lack 
of maintenance. Impact and vibratory pile installation and vibratory 
pile removal would introduce underwater sounds at levels that may 
result in take, by Level A and Level B harassment, of marine mammals in 
the Columbia River Estuary. Construction activities are expected to 
last between 6 and 41 days.

Dates and Duration

    The work is anticipated to take between 6 and 41 days with work 
occurring during standard daylight working hours, 8 to 10 hours per 
day, beginning on September 15, 2019. Work is planned to take place in 
September, October, or November.

Specific Geographic Region

    The proposed work would occur at the Sand Island pile dikes in 
Clatsop County, Oregon. The Sand Island pile dikes are located near the 
MCR. The pile dike at RM 4.01 is located within Oregon, while the pile 
dike at RM 6.37 is in both Oregon and Washington. The MCR is 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 upstream to Bonneville Dam at RM 
146.

Detailed Description of Specific Activity

    Records from previous timber pile dike repairs concluded that 
trying to drive new timber piles through the existing scour protection 
rock apron at the base of the pile dike was challenging and would 
likely not meet sufficient embedment depths or alignment tolerances 
needed for structural and functional requirements. Since timber piles 
had insufficient structural capacity to support necessary environmental 
loading, steel piles were selected for all potential design options.
    Preliminary pile dike repair design revealed three options, 
hereafter described as the offset alignment, existing alignment, and 
sleeve existing piles. The Corps needs to drive test piles in order to 
evaluate which of these three designs could achieve the most favorable 
hydraulic and sediment transport functions, while also considering 
costs associated with construction and long-term maintenance.
    The Sand Island Pile Dike System Test Piles project entails testing 
the three aforementioned designs at two pile dikes, each with 9 piles. 
The Corps has designed a specific testing sequence in which up to 3 
tests could occur at each of those 18 piles, yielding a total of 41 
pile driving events over a maximum of 41 days. The test sequence at any 
given location includes an attempt with a vibratory hammer or impact 
hammer with various shoes including ring, cone, or rock tip (See Table 
1).
    The maximum 41 days of work includes the following estimates for 
various pile driving activities:
     Up to 20 days of impact driving only (steel piles);
     Up to 18 days of impact driving AND vibratory 
installation/removal of steel piles; and
     Up to 3 days for vibratory removal of timber piles only.
    Piles are generally installed by a rig which supports the pile 
leads, raises the pile, and operates a hammer. The rigs will use either 
impact hammers or vibratory drivers. Up to ten existing timber piles 
may be removed by vibratory methods, pulling, cutting or snapping at 
the approximate level of the enrockment. Removal with a vibratory 
hammer is expected to take approximately 5 minutes. After timber pile 
removal, one of the test methods would be attempted. When refusal 
criteria is reached, the attempt would cease and the next test method 
would be attempted as prescribed in the work summary.
    The contractor may use barge-mounted cranes equipped with survey 
grade positioning software to ensure the piles are installed with 
precision. Driving shoes may also be used. Should unusually difficult 
driving conditions be encountered, the contractor will be allowed to 
temporarily excavate the minimum amount of existing scour protection 
rock needed in order to drive new piles. The contractor will then 
reinstall the rock to provide scour protection for new piles. Barges 
will transport all equipment and material to and from the site and 
serve as staging platforms for construction. Barges may be spudded or 
anchored into position. Test piles will be removed upon completion of 
the tests.
    Pile driving for test piles may be done with either vibratory or 
impact hammer, but due to existing enrockment surrounding existing 
piles, it is anticipated that impact hammer will primarily be used. It 
is not possible to use bubble curtains or other noise-attenuating 
devices due to heavy tidal action.

                                                              Table 1--Pile Driving Summary
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                             Number of
                                                                                             Number of       Number of       Number of      steel piles
                                                                                           timber piles     steel pile      steel pile     for vibratory
  Pile location and alignment         1st test            2nd test          3rd test       for vibratory  driving events  driving events   removal after
                                                                                              removal     with vibratory    with impact       testing
                                                                                             (maximum)        hammer          hammer         (maximum)
--------------------------------------------------------------------------------------------------------------------------------------------------------
4-1C Center...................  Pile Only \1\.......  Ring \3\........  Cone \4\........  ..............               1               2               1
4-1F Offset...................  Pile Only...........  Ring............  Cone............  ..............               1               2               1
4-2C Center...................  Ring................  Cone............  ................  ..............  ..............               2               1
4-2F Offset...................  Cone................  Rock Tip \5\....  ................  ..............  ..............               2               1
4-3C Center...................  Ring................  Cone............  ................  ..............  ..............               2               1
4-3F Offset...................  Ring................  Cone............  ................  ..............  ..............               2               1

[[Page 38229]]

 
4-4C Center...................  Cone................  Rock Tip........  ................  ..............  ..............               2               1
4-4F Offset...................  Ring................  Cone............  ................  ..............  ..............               2               1
4-S Center....................  Pile Only+Sleeve \2\  Ring............  ................  ..............               1               1               1
6-1C Center...................  Cone................  Rock Tip........  ................  ..............  ..............               2               1
6-1F Offset...................  Pile Only...........  Ring............  Cone............  ..............               1               2               1
6-2C Center...................  Ring................  Cone............  ................  ..............  ..............               2               1
6-2F Offset...................  Ring................  Cone............  ................  ..............  ..............               2               1
6-3C Center...................  Cone................  Rock Tip........  ................  ..............  ..............               2               1
6-3F Offset...................  Ring................  Cone............  ................  ..............  ..............               2               1
6-4C Center...................  Pile Only...........  Ring............  Cone............  ..............               1               2               1
6-4F Offset...................  Pile Only...........  Ring............  Cone............  ..............               1               2               1
6-S Center....................  Pile Only+Sleeve....  Ring............  ................  ..............               1               1               1
                                                                                         ---------------------------------------------------------------
    Totals....................  ....................  ................  ................              10               7              34              18
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Pile only consists of only the open steel pile without an end treatment.
\2\ Pile only+sleeve consists of an attempt to drive the new test pile as a sleeve over the existing timber piles.
\3\ Ring consists of the steel pile fitted with an open-ended cutting shoe.
\4\ Cone consists of the steel pile fitted with a conical shoe.
\5\ Rock tip consists of the steel pile fitted with a conical rock-breaking tip.

    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's 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's 
website (https://www.fisheries.noaa .gov/find-species).
    Table 2 lists all species with expected potential for occurrence 
near the test piles project area and summarizes information related to 
the population or stock, including regulatory status under the MMPA and 
ESA and potential biological removal (PBR), where known. For taxonomy, 
we follow Committee on Taxonomy (2016). 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's SARs). While no mortality is anticipated or authorized here, PBR 
and annual serious injury and mortality from anthropogenic sources are 
included here as gross indicators of the status of the species and 
other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's 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's U.S. Pacific Marine Mammal SARs (Carretta et al., 2019). All 
values presented in Table 2 are the most recent available at the time 
of publication and are available in the 2018 SARs (Carretta et al., 
2019).

               Table 2--Marine Mammal Species Likely To Be Found Near the Test Piles Project Area
----------------------------------------------------------------------------------------------------------------
                                                                             Stock abundance
                                                                  ESA/MMPA   (CV, Nmin, most
         Common name           Scientific name       Stock         status;        recent         PBR    Annual M/
                                                                  strategic     abundance                SI \3\
                                                                  (Y/N) \1\    survey) \2\
----------------------------------------------------------------------------------------------------------------
                      Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
----------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray whale...............  Eschrichtius     Eastern North    -, -, N     26,960 (0.05,         801       139
                                robustus.        Pacific.                     25849, 2016).
Family Balaenopteridae
 (rorquals):
    Humpback whale...........  Megaptera        California/      -, -, Y     2,900 (0.05,         16.7      40.2
                                novaeangliae.    Oregon/                      2,784, 2014).
                                                 Washington.
----------------------------------------------------------------------------------------------------------------
                        Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
----------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer whale.............  Orcinus orca...  West Coast       -, -, N     243 (N/A, 243,        2.4         0
                                                 Transient.                   2009).
Family Phocoenidae
 (porpoises):
    Harbor porpoise..........  Phocoena         Northern Oregon/ -, -, N     21,487 (044,          151       3.0
                                phocoena.        Washington                   15,123, 2011).
                                                 Coast.
----------------------------------------------------------------------------------------------------------------

[[Page 38230]]

 
                                     Order Carnivora--Superfamily Pinnipedia
----------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals
 and sea lions):
    California sea lion......  Zalophus         U.S. Stock.....  -, -, N     257,606 (N/A,      14,011      >320
                                californianus.                                233,515, 2014).
    Steller sea lion.........  Eumetopias       Eastern U.S....  -, -, N     41,638 (See         2,498       108
                                jubatus.                                      SAR, 41,638,
                                                                              2015).
Family Phocidae (earless
 seals):
    Harbor seal..............  Phoca vitulina   Oregon and       -, -, N     UNK (UNK, UNK,        UND      10.6
                                richardii.       Washington                   1999).
                                                 Coast.
----------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-)
  indicates that the species is not listed under the ESA or designated as depleted under the MMPA. Under the
  MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is
  determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or
  stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of
  variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury
  from all sources combined (e.g., commercial fisheries, ship strike). Annual M/SI often cannot be determined
  precisely and is in some cases presented as a minimum value or range. A CV associated with estimated mortality
  due to commercial fisheries is presented in some cases.

    All species that could potentially occur in the proposed project 
area are included in Table 2. However, the temporal and/or spatial 
occurrence of gray, humpback, and killer whales is such that take is 
not expected to occur, and they are not discussed further beyond the 
explanation provided here.
    Gray whales have not been documented near the proposed project area 
although anecdotal evidence indicates they have been seen at the MCR. 
However, they are not a common visitor as they mostly remain in the 
vicinity of the offshore shelf-break (Griffith 2015). They migrate 
along the Oregon coast in three discernible phases from early December 
through May (Herzing and Mate 1984). Therefore, they are unlikely to 
occur near the project area in September, October, or November. 
Additionally, NMFS issued an IHA to the Corps for incidental take of 
marine mammals associated with vibratory driving activities occurring 
at Jetty A which is located approximately 2.5 km east of RM 4.01 (80 FR 
53777, September 8, 2015). The Level B harassment zone established for 
that project overlaps with the proposed Level B harassment zone for 
this proposed test piles project. A marine mammal monitoring report 
submitted to NMFS on August 1, 2016 included 5 days of observation in 
June and July of 2016. During that time there were no gray whale 
sightings. A subsequent marine mammal monitoring report was submitted 
by the Corps on December 7, 2017 as part of the reporting requirements 
for a Letter of Authorization (LOA) issued for the rehabilitation of 
the entire Columbia River Jetty System (82 FR 15046; March 23, 2017). 
Monitoring by two PSOs during work on Jetty A for two days in July 2017 
resulted in no gray whale sightings. Given the size of these whales 
they could be readily identifiable at a considerable distance. If a 
gray whale were to approach the established Level B harassment 
isopleths, shutdown would be initiated to avoid take. The Corps plan to 
employ at least one vessel-based PSO who would be able to adequately 
monitor these zones. Therefore, NMFS does expect take to occur.
    Humpback whales have been observed in the vicinity of the project 
area in recent years. They have been arriving in the lower Columbia 
estuary 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. While it is possible that humpback whales 
could pass through the project area during the construction period, 
there is a decreased chance of their presence in September, October, 
and November. The 2016 Jetty A monitoring report recorded nine 
sightings of humpback whale during the five-day in-water construction 
period but only a single sighting occurred within the Level B 
harassment zone. Furthermore, these sightings occurred at the peak of 
forage fish abundance in June and July. The 2017 LOA monitoring report 
did not record any sightings. The Corps would initiate shutdown if a 
humpback was observed approaching the Level B harassment zones. 
Humpbacks are readily identifiable from a distance, and the Corps will 
be placing Protected Species Monitors (PSOs) on at least one boat to 
ensure complete coverage of harassment zones. Therefore, take of 
humpback whales is not anticipated.
    Killer whales from the Southern Resident and West Coast transient 
stocks could occur near the MCR. Historically, killer whales were 
regular visitors in the vicinity of the estuary. However, they are much 
less common presently and are rarely seen in the interior of the 
Columbia River Jetty system (Wilson 2015). While not regularly seen in 
the project area, West Coast Transient killer whales have been observed 
near the MCR during the peak spring Chinook salmon migration in March 
and April but members of this stock are not likely to occur in the 
vicinity of the project area during the proposed construction period. 
Both the 2016 Corps monitoring report and 2017 monitoring report did 
not record any killer whale sightings. Due to the absence of killer 
whales observations in the project vicinity, the limited timeframe of 
proposed pile driving activities, it is highly unlikely that killer 
whales would be near the Sand Island pile dike system. Should any 
killer whales be observed approaching the Level B harassment zone, 
shutdown procedures would be implemented. Therefore, take of killer 
whales is not expected.

Harbor Porpoise

    In the eastern North Pacific Ocean, harbor porpoise are found in 
coastal and inland waters from Point Barrow, along the Alaskan coast, 
and down the west coast of North America to Point Conception, 
California. Harbor porpoise are known to occur year-round in the inland 
trans-boundary waters of Washington and British Columbia, Canada and 
along the Oregon/

[[Page 38231]]

Washington coast. The Northern Oregon/Washington Coast stock of harbor 
porpoises ranges from Lincoln City, OR, to Cape Flattery, WA (Carretta 
et al. 2019).
    Harbor porpoises are usually found in shallow water, most often 
nearshore, although they occasionally travel over deeper offshore 
waters (NOAA 2013a). West Coast populations have more restricted 
movements and do not migrate as much as East Coast populations (Halpin, 
OBIS-SEAMAP 2019). 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 MCR (Griffith 2015). Their abundance peaks 
with the abundance of anchovy presence in the river and nearshore.

California Sea Lion

    California sea lions are found along the west coast from the 
southern tip of Baja California to southeast Alaska. They breed mainly 
on offshore islands from Southern California's Channel Islands south to 
Mexico. Non-breeding males often roam north in spring foraging for 
food. 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 use the nearby South Jetty for hauling out (Jeffries 2000). 
According to Oregon Department of Fish and Wildlife (ODFW 2014) counts 
most California sea lions are concentrated near the tip of the South 
Jetty. 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 absence there can be several hundred using the South Jetty. 
More frequent Washington Department of Fish and Wildlife (WDFW 2014) 
surveys indicate greater numbers in the summer, and use remains 
concentrated to fall and winter months. Nearly all California sea lions 
in the Pacific Northwest are sub-adult and adult males (females and 
young generally stay in California).

Steller Sea Lion

    The range of the Steller sea lion includes the North Pacific Ocean 
rim from California to northern Japan. Steller sea lions forage in 
nearshore and pelagic waters where they are opportunistic predators. 
Steller sea lion populations that primarily occur east of 144[deg] W 
(Cape Suckling, Alaska) comprise the Eastern Distinct Population 
Segment (DPS) (Carretta et al. 2019).
    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 ODFW (2014), during the 
summer months it is not uncommon to observe between 500-1,000 Steller 
sea lions present per day. 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.
    While California sea lions also use this area and can intermingle 
with Steller sea lions, it appears that Steller out-compete California 
sea lions for the preferred haul out area. Previous monthly averages 
between 1995 and 2004 for Steller sea lions hauled out at the South 
Jetty head ranged from about 168 to 1,106 animals. ODFW data from 2000-
2014 reflects a lower frequency of surveys, and numbers ranged from 
zero animals to 606 Steller sea lions (ODFW 2014). More frequent 
surveys by WDFW for the same time frame (2000-2014) put the monthly 
range at 177 to 1,663 animals throughout the year.

Harbor Seal

    Harbor seals range from Baja California, north along the western 
coasts of the United States, British Columbia and southeast Alaska, 
west through the Gulf of Alaska, Prince William Sound, and the Aleutian 
Islands, and north in the Bering Sea to Cape Newenham and the Pribilof 
Islands. They are one of the most abundant pinnipeds in Oregon and can 
typically be found in coastal marine and estuarine waters of the Oregon 
coast throughout the year. On land, they can be found on offshore rocks 
and islands, along shore, and on exposed flats in the estuary (Harvey 
1987). 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. Harbor 
seals do not make extensive pelagic migrations. (Carretta et al. 2019)

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. Current data indicate that 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) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 3.

[[Page 38232]]



                  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 (dolphins,     150 Hz to 160 kHz.
 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) (true    50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea    60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Seven marine mammal species (three cetacean and three pinniped (two 
otariid and one phocid) species) have the reasonable potential to co-
occur at the time of the proposed survey activities. Please refer to 
Table 2. Of the cetacean species that may be present, two are 
classified as low-frequency cetaceans (i.e., all mysticete species), 
one is classified as a mid-frequency cetacean (i.e., all delphinid and 
ziphiid species and the sperm whale), and one is classified as a high-
frequency cetacean (i.e., harbor porpoise and Kogia spp.).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take by Incidental Harassment 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 by Incidental Harassment 
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 how those impacts on 
individuals are likely to impact marine mammal species or stocks.
    Acoustic effects on marine mammals during the specified activity 
can occur from vibratory and impact pile driving as well vibratory pile 
removal. The effects of underwater noise from the Corps' proposed 
activities have the potential to result in Level A and Level B 
harassment of marine mammals in the vicinity of the project area.

Description of Sound Sources

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

[[Page 38233]]

may be either directed in a beam or beams or may radiate in all 
directions (omnidirectional sources), as is the case for sound produced 
by the pile driving activity considered here. The compressions and 
decompressions associated with sound waves are detected as changes in 
pressure by aquatic life and man-made sound receptors such as 
hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound, which is 
defined as environmental background sound levels lacking a single 
source or point (Richardson et al., 1995). The sound level of a region 
is defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., wind and 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
(e.g., vessels, dredging, construction) sound. A number of sources 
contribute to ambient sound, including wind and waves, which are a main 
source of naturally occurring ambient sound for frequencies between 200 
Hz and 50 kilohertz (kHz) (Mitson, 1995). In general, ambient sound 
levels tend to increase with increasing wind speed and wave height. 
Precipitation can become an important component of total sound at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times. Marine mammals can contribute significantly to ambient sound 
levels, as can some fish and snapping shrimp. The frequency band for 
biological contributions is from approximately 12 Hz to over 100 kHz. 
Sources of ambient sound related to human activity include 
transportation (surface vessels), dredging and construction, oil and 
gas drilling and production, geophysical surveys, sonar, and 
explosions. Vessel noise typically dominates the total ambient sound 
for frequencies between 20 and 300 Hz. In general, the frequencies of 
anthropogenic sounds are below 1 kHz and, if higher frequency sound 
levels are created, they attenuate rapidly.
    The sum of the various natural and anthropogenic sound sources that 
comprise ambient sound at any given location and time depends not only 
on the source levels (as determined by current weather conditions and 
levels of biological and human activity) but also on the ability of 
sound to propagate through the environment. In turn, sound propagation 
is dependent on the spatially and temporally varying properties of the 
water column and sea floor, and is frequency-dependent. As a result of 
the dependence on a large number of varying factors, ambient sound 
levels can be expected to vary widely over both coarse and fine spatial 
and temporal scales. Sound levels at a given frequency and location can 
vary by 10-20 dB from day to day (Richardson et al., 1995). The result 
is that, depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    Sounds are often considered to fall into one of two general types: 
pulsed and non-pulsed (defined in the following). The distinction 
between these two sound types is important because they have differing 
potential to cause physical effects, particularly with regard to 
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see 
Southall et al. (2007) for an in-depth discussion of these concepts. 
The distinction between these two sound types is not always obvious, as 
certain signals share properties of both pulsed and non-pulsed sounds. 
A signal near a source could be categorized as a pulse, but due to 
propagation effects as it moves farther from the source, the signal 
duration becomes longer (e.g., Greene and Richardson, 1988).
    Pulsed sound sources (e.g., airguns, explosions, gunshots, sonic 
booms, impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur 
either as isolated events or repeated in some succession. Pulsed sounds 
are all characterized by a relatively rapid rise from ambient pressure 
to a maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or intermittent (ANSI, 1995; 
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, and active sonar systems. The 
duration of such sounds, as received at a distance, can be greatly 
extended in a highly reverberant environment.
    The impulsive sound generated by impact hammers is characterized by 
rapid rise times and high peak levels. Vibratory hammers produce non-
impulsive, continuous noise at levels significantly lower than those 
produced by impact hammers. Rise time is slower, reducing the 
probability and severity of injury, and sound energy is distributed 
over a greater amount of time (e.g., Nedwell and Edwards, 2002; Carlson 
et al., 2005).

Acoustic Effects on Marine Mammals

    We previously provided general background information on marine 
mammal hearing (see ``Description of Marine Mammals in the Area of the 
Specified Activity''). Here, we discuss the potential effects of sound 
on marine mammals.
    Note that, in the following discussion, we refer in many cases to a 
review article concerning studies of noise-induced hearing loss 
conducted from 1996-2015 (i.e., Finneran, 2015). For study-specific 
citations, please see that work. Anthropogenic sounds cover a broad 
range of frequencies and sound levels and can have a range of highly 
variable impacts on marine life, from none or minor to potentially 
severe responses, depending on received levels, duration of exposure, 
behavioral context, and various other factors. The potential effects of 
underwater sound from active acoustic sources can potentially result in 
one or more of the following: temporary or permanent hearing 
impairment, non-auditory physical or physiological effects, behavioral 
disturbance, stress, and masking (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007; G[ouml]tz et 
al., 2009). The degree of effect is intrinsically related to the signal 
characteristics, received level, distance from the source, and duration 
of the sound exposure. In general, sudden, high level sounds can cause 
hearing loss, as can longer exposures to lower level sounds. Temporary 
or permanent loss of hearing will occur almost exclusively for noise 
within an animal's hearing range. We first describe specific 
manifestations of acoustic effects before providing discussion specific 
to pile driving and removal activities.
    Richardson et al. (1995) described zones of increasing intensity of 
effect that might be expected to occur, in relation to distance from a 
source and assuming that the signal is within an animal's hearing 
range. First is the area within which the acoustic signal would be 
audible (potentially perceived) to the

[[Page 38234]]

animal but not strong enough to elicit any overt behavioral or 
physiological response. The next zone corresponds with the area where 
the signal is audible to the animal and of sufficient intensity to 
elicit behavioral or physiological responsiveness. Third is a zone 
within which, for signals of high intensity, the received level is 
sufficient to potentially cause discomfort or tissue damage to auditory 
or other systems. Overlaying these zones to a certain extent is the 
area within which masking (i.e., when a sound interferes with or masks 
the ability of an animal to detect a signal of interest that is above 
the absolute hearing threshold) may occur; the masking zone may be 
highly variable in size.
    We describe the more severe effects (i.e., certain non-auditory 
physical or physiological effects) only briefly as we do not expect 
that there is a reasonable likelihood that pile driving may result in 
such effects (see below for further discussion). Potential effects from 
explosive impulsive sound sources can range in severity from effects 
such as behavioral disturbance or tactile perception to physical 
discomfort, slight injury of the internal organs and the auditory 
system, or mortality (Yelverton et al., 1973). Non-auditory 
physiological effects or injuries that theoretically might occur in 
marine mammals exposed to high level underwater sound or as a secondary 
effect of extreme behavioral reactions (e.g., change in dive profile as 
a result of an avoidance reaction) caused by exposure to sound include 
neurological effects, bubble formation, resonance effects, and other 
types of organ or tissue damage (Cox et al., 2006; Southall et al., 
2007; Zimmer and Tyack, 2007). The construction activities considered 
here do not involve the use of devices such as explosives or mid-
frequency tactical sonar that are associated with these types of 
effects.
    Threshold Shift--Marine mammals exposed to high-intensity sound, or 
to lower-intensity sound for prolonged periods, can experience hearing 
threshold shift (TS), which is the loss of hearing sensitivity at 
certain frequency ranges (Finneran, 2015). TS can be permanent (PTS), 
in which case the loss of hearing sensitivity is not fully recoverable, 
or temporary (TTS), in which case the animal's hearing threshold would 
recover over time (Southall et al., 2007). Repeated sound exposure that 
leads to TTS could cause PTS. In severe cases of PTS, there can be 
total or partial deafness, while in most cases the animal has an 
impaired ability to hear sounds in specific frequency ranges (Kryter, 
1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several decibels above (a 40-dB threshold shift approximates PTS onset; 
e.g., Kryter et al., 1966; Miller, 1974) that inducing mild TTS (a 6-dB 
threshold shift approximates TTS onset; e.g., Southall et al. 2007). 
Based on data from terrestrial mammals, a precautionary assumption is 
that the PTS thresholds for impulse sounds (such as impact pile driving 
pulses as received close to the source) are at least 6 dB higher than 
the TTS threshold on a peak-pressure basis and PTS cumulative sound 
exposure level thresholds are 15 to 20 dB higher than TTS cumulative 
sound exposure level thresholds (Southall et al., 2007). Given the 
higher level of sound or longer exposure duration necessary to cause 
PTS as compared with TTS, it is considerably less likely that PTS could 
occur.
    TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. Few data 
on sound levels and durations necessary to elicit mild TTS have been 
obtained for marine mammals.
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. 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. For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that occurs during a time 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.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and three species of pinnipeds (northern elephant 
seal, harbor seal, and California sea lion) exposed to a limited number 
of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (Finneran, 2015). TTS was not observed in trained 
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to 
impulsive noise at levels matching previous predictions of TTS onset 
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises 
have a lower TTS onset than other measured pinniped or cetacean species 
(Finneran, 2015). Additionally, the existing marine mammal TTS data 
come from a limited number of individuals within these species. There 
are no data available on noise-induced hearing loss for mysticetes. For 
summaries of data on TTS in marine mammals or for further discussion of 
TTS onset thresholds, please see Southall et al. (2007), Finneran and 
Jenkins (2012), Finneran (2015), and NMFS (2018).
    Behavioral Effects--Behavioral disturbance may include a variety of 
effects, including subtle changes in behavior (e.g., minor or brief 
avoidance of an area or changes in vocalizations), more conspicuous 
changes in similar behavioral activities, and more sustained and/or 
potentially severe reactions, such as displacement from or abandonment 
of high-quality habitat. Behavioral responses to sound are highly 
variable and context-specific and any reactions depend on numerous 
intrinsic and extrinsic factors (e.g., species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day), as well as the interplay between factors (e.g., 
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007; 
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not 
only among individuals but also within an individual, depending on 
previous experience with a sound source, context, and numerous other 
factors (Ellison et al., 2012), and can vary depending on 
characteristics associated

[[Page 38235]]

with the sound source (e.g., whether it is moving or stationary, number 
of sources, distance from the source). Please see Appendices B-C of 
Southall et al. (2007) for a review of studies involving marine mammal 
behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure. As noted, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically airguns or acoustic harassment 
devices) have been varied but often consist of avoidance behavior or 
other behavioral changes suggesting discomfort (Morton and Symonds, 
2002; see also Richardson et al., 1995; Nowacek et al., 2007). However, 
many delphinids approach low-frequency airgun source vessels with no 
apparent discomfort or obvious behavioral change (e.g., Barkaszi et 
al., 2012), indicating the importance of frequency output in relation 
to the species' hearing sensitivity.
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al.; 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior 
may reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from airgun surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996). The result of a flight response could range from 
brief,

[[Page 38236]]

temporary exertion and displacement from the area where the signal 
provokes flight to, in extreme cases, marine mammal strandings (Evans 
and England, 2001). However, it should be noted that response to a 
perceived predator does not necessarily invoke flight (Ford and Reeves, 
2008), and whether individuals are solitary or in groups may influence 
the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996). However, Ridgway et al. (2006) 
reported that increased vigilance in bottlenose dolphins exposed to 
sound over a five-day period did not cause any sleep deprivation or 
stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress Responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003).
    Auditory 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; Erbe et al., 
2016). 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., 
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.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
when disrupting or altering critical behaviors. It is important to 
distinguish TTS and PTS, which persist after the sound exposure, from 
masking, which occurs during the sound exposure. Because masking 
(without resulting in TS) is not associated with abnormal physiological 
function, it is not considered a physiological effect, but rather a 
potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by

[[Page 38237]]

anthropogenic noise may be considered as a reduction in the 
communication space of animals (e.g., Clark et al., 2009) and may 
result in energetic or other costs as animals change their vocalization 
behavior (e.g., Miller et al., 2000; Foote et al., 2004; Parks et al., 
2007; Di Iorio and Clark, 2009;). Masking can be reduced in situations 
where the signal and noise come from different directions (Richardson 
et al., 1995), through amplitude modulation of the signal, or through 
other compensatory behaviors (Houser and Moore, 2014). Masking can be 
tested directly in captive species (e.g., Erbe, 2008), but in wild 
populations it must be either modeled or inferred from evidence of 
masking compensation. There are few studies addressing real-world 
masking sounds likely to be experienced by marine mammals in the wild 
(e.g., Branstetter et al., 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand, 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    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 or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. We recognize that 
pinnipeds in the water could be exposed to airborne sound that may 
result in behavioral harassment when looking with their heads above 
water. Most likely, airborne sound would cause behavioral responses 
similar to those discussed above in relation to underwater sound. For 
instance, anthropogenic sound could cause hauled out pinnipeds to 
exhibit changes in their normal behavior, such as reduction in 
vocalizations, or cause them to temporarily abandon the area and move 
further from the source. However, these animals would previously have 
been `taken' because of exposure to underwater sound above the 
behavioral harassment thresholds, which are in all cases larger than 
those associated with airborne sound. Thus, the behavioral harassment 
of these animals is already accounted for in these estimates of 
potential take. Therefore, we do not believe that authorization of 
incidental take resulting from airborne sound for pinnipeds is 
warranted, and airborne sound is not discussed further here.
    Potential Effects of the Corps' Proposed Activity--As described 
previously (see ``Description of Active Acoustic Sound Sources''), the 
Corps proposes to conduct impact and vibratory driving as well as 
vibratory removal. The effects of pile driving on marine mammals are 
dependent on several factors, including the size, type, and depth of 
the animal; the depth, intensity, and duration of the pile driving 
sound; the depth of the water column; the substrate of the habitat; the 
standoff distance between the pile and the animal; and the sound 
propagation properties of the environment. With both types, it is 
likely that the pile driving could result in temporary, short term 
changes in an animal's typical behavioral patterns and/or avoidance of 
the affected area. These behavioral changes may include (Richardson et 
al., 1995): 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; and/or flight 
responses.
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, or reproduction. Significant 
behavioral modifications that could lead to effects on growth, 
survival, or reproduction, such as drastic changes in diving/surfacing 
patterns or significant habitat abandonment are extremely unlikely in 
this area (i.e., relatively shallow waters in an area with considerable 
vessel traffic).
    Whether impact or vibratory driving, sound sources would be active 
for relatively short durations, with relation to potential for masking. 
The frequencies output by pile driving activity are lower than those 
used by most species expected to be regularly present for communication 
or foraging. We expect insignificant impacts from masking, and any 
masking event that could possibly rise to Level B harassment under the 
MMPA would occur concurrently within the zones of behavioral harassment 
already estimated for vibratory and impact pile driving, and which have 
already been taken into account in the exposure analysis.

Anticipated Effects on Marine Mammal Habitat

    The proposed activities would not result in permanent impacts to 
habitats used directly by marine mammals except the actual footprint of 
the project. The footprint of the project covers a small section of the 
Sand Island Pile Dike system.
    The proposed activities may have potential short-term impacts to 
food sources such as forage fish. The proposed activities could also 
affect acoustic habitat (see masking discussion above), but meaningful 
impacts are unlikely. There are no known foraging hotspots, or other 
ocean bottom structures of significant biological importance to marine 
mammals present in the marine waters in the vicinity of the project 
areas. Therefore, the main impact issue associated with the proposed 
activity would be temporarily elevated sound levels and the associated 
direct effects on marine mammals, as discussed previously. The most 
likely impact to marine mammal habitat occurs from pile driving effects 
on likely marine mammal prey (i.e., fish) near where the piles are 
installed. Impacts to the immediate substrate during installation and 
removal of piles would be minor since piles would be driven through 
existing enrockment structures. This could result in limited, temporary 
suspension of sediments, which could impact water quality and 
visibility for a short amount of time, but which would not be expected 
to have any effects on individual marine mammals. Impacts to substrate 
are therefore not discussed further.
    Effects to Prey--Sound may affect marine mammals through impacts on 
the abundance, behavior, or distribution of prey species (e.g., 
crustaceans, cephalopods, fish, zooplankton). Marine mammal prey varies 
by species, season, and location and, for some, is not well documented. 
Here, we describe studies regarding the effects of noise on known 
marine mammal prey.
    Fish utilize the soundscape and components of sound in their

[[Page 38238]]

environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fishes hear sounds using pressure and 
particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
Hastings and Popper (2005) identified several studies that suggest fish 
may relocate to avoid certain areas of sound energy. Additional studies 
have documented effects of pile driving on fish, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). Several studies have demonstrated that impulse sounds might 
affect the distribution and behavior of some fishes, potentially 
impacting foraging opportunities or increasing energetic costs (e.g., 
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 
1992; Santulli et al., 1999; Paxton et al., 2017). However, some 
studies have shown no or slight reaction to impulse sounds (e.g., Pena 
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott 
et al., 2012). More commonly, though, the impacts of noise on fish are 
temporary.
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours 
for one species. Impacts would be most severe when the individual fish 
is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    The most likely impact to fish from pile driving activities at the 
project areas would be temporary behavioral avoidance of the area. The 
duration of fish avoidance of an area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. In general, impacts to marine mammal prey 
species are expected to be minor and temporary due to the expected 
short daily duration of individual pile driving events and the 
relatively small areas being affected.
    In summary, given the short duration of sound (5-60 minutes) 
associated with individual pile driving and removal events and the 
small area being affected relative to available nearby habitat, pile 
driving and removal activities associated with the proposed action are 
not likely to have a permanent, adverse effect on any fish habitat, or 
populations of fish species or other prey. 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.
    The area impacted by the project is relatively small compared to 
the available habitat in the MCR area. Any behavioral avoidance by fish 
of the disturbed area would still leave significantly large areas of 
fish and marine mammal foraging habitat in the nearby vicinity. As 
described in the preceding, the potential for the Corps' construction 
to affect the availability of prey to marine mammals or to meaningfully 
impact the quality of physical or acoustic habitat is considered to be 
insignificant. Effects to habitat will not be discussed further in this 
document.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    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 
impact and vibratory pile driving has the potential to result in 
disruption of behavioral patterns for individual marine mammals. There 
is also some potential for auditory injury (Level A harassment) to 
result, primarily for high frequency species and phocids because 
predicted auditory injury zones are larger than for low-frequency 
species, mid-frequency species and otariids. Auditory injury is 
unlikely to occur for low-frequency species, mid-frequency species and 
otariids. The proposed mitigation and monitoring measures are expected 
to minimize the severity of such taking to the extent practicable.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    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) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of 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 
estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed 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).

[[Page 38239]]

    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g., 
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms) 
for non-explosive impulsive (e.g., seismic airguns) or intermittent 
(e.g., scientific sonar) sources.
    The Corps' proposed activity includes the use of continuous 
(vibratory pile driving) and impulsive (impact pile driving) sources, 
and therefore the 120 and 160 dB re 1 [mu]Pa (rms) are applicable.
    Level A harassment for non-explosive sources--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 Corp's proposed activity includes the 
use of impulsive (impact pile driving) and non-impulsive (vibratory 
pile driving) source.
    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 will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.

Sound Propagation

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

TL = B * log10 (R1/R2),

where:

    B = transmission loss coefficient (assumed to be 15)
    R1 = the distance of the modeled SPL from the driven 
pile, and
    R2 = the distance from the driven pile of the initial 
measurement.

This formula neglects loss due to scattering and absorption, which is 
assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive conditions including in-water structures and 
sediments. 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)). 
As is common practice in coastal waters, here we assume practical 
spreading loss (4.5 dB reduction in sound level for each doubling of 
distance). Practical spreading is a compromise that is often used under 
conditions where water depth increases as the receiver moves away from 
the shoreline, resulting in an expected propagation environment that 
would lie between spherical and cylindrical spreading loss conditions.

Sound Source Levels

    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. There are no source 
level measurements available the piles proposed for installation at 
part of the test piles project. Sound pressure levels for impact 
driving of 24-in steel piles

[[Page 38240]]

were taken from Caltrans 2015. Vibratory driving source levels for 24-
in steel piles came from the United States Navy (2015). There was no 
data available pertaining to vibratory removal of 24-in timber piles. 
NMFS recommended that the Corps use data derived from Washington 
Department of Transportation Seattle Pier 62 project collected by the 
Greenbusch Group (2018) for vibratory removal of 14-in timber piles. 
NMFS reviewed the Greenbusch Group (2018) report and determined that 
the findings were incorrectly derived by pooling together all steel 
pile and timber pile measurements at various distances. Furthermore, 
the data was not normalized to the standard 10 m distance. NMFS 
analyzed source measurements at different distances for all 63 
individual timber piles that were removed and normalized the values to 
10 m. The results showed that the median is 152 dB SPLrms. This value 
was used as the proxy source level for vibratory removal of 24-in 
timber piles as shown in Table 5.

 Table 5--Estimated Unattenuated Underwater Sound Pressure Levels Associated With Pile Installation and Removal
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
Pile type & activity                                       Sound source level at 10 m
----------------------------------------------------------------------------------------------------------------
24-Inch Steel Pile Impact       203 dBPK..................  190 dBRMS................  177 dBSEL.
 Installation \1\.
24-Inch Steel Piles Vibratory   Not Available.............  161 dBRMS................  Not Available.
 Installation/Removal \2\.
24-Inch Timber Pile Vibratory   Not Available.............  152 dBRMS................  Not Available.
 Removal \3\.
----------------------------------------------------------------------------------------------------------------
\1\ From CalTrans 2015 Table I.2-1. Summary of Near-Source (10-Meter) Unattenuated Sound Pressure Levels for In-
  Water Pile Driving Using an Impact Hammer: 0.61-meter (24-inch) steel pipe pile in water ~5 meters deep.
\2\ From United States Navy. 2015. Prepared by Michael Slater, Naval Surface Warfare Center, Carderock Division,
  and Sharon Rainsberry, Naval Facilities Engineering Command Northwest. Revised January 2015. Table 2-2.
\3\ Due to the lack of information for vibratory removal of 24'' diameter timber piles, an estimate based on
  removal of 14-inch timber piles is used as a proxy (Greenbusch Group, 2018)

Level A Harassment

    When the NMFS Technical Guidance (2016) was published, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of Level A harassment take. However, these tools offer the 
best way to predict appropriate isopleths when more sophisticated 3D 
modeling methods are not available, and NMFS continues to develop ways 
to quantitatively refine these tools, and will qualitatively address 
the output where appropriate. For stationary sources such as pile 
driving, NMFS User Spreadsheet predicts the closest distance at which, 
if a marine mammal remained at that distance the whole duration of the 
activity, it would not incur PTS. Inputs used in the User Spreadsheet, 
and the resulting isopleths are reported below in Table 6.

            Table 6--NMFS Technical Guidance (2018) User Spreadsheet Input To Calculate PTS Isopleths
----------------------------------------------------------------------------------------------------------------
                                          24-in steel impact     24-in steel vibratory      24-in timber pile
                Inputs                       installation         installation/removal           removal
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used.................  E. (1) Impact Pile       A. (1) Vibratory Pile    A. (1) Vibratory Pile
                                        Driving.                 Driving.                 Driving.
Source Level (Single Strike/shot SEL)  177 dB SEL/203 dB Peak.  161 dB RMS.............  152 dB RMS
Weighting Factor Adjustment (kHz)....  2......................  2.5....................  2.5
Number of strikes per pile...........  550....................  .......................  .......................
Number of piles per day..............  6......................  6......................  6
Duration to install/removal single     60.....................  30/5...................  5
 pile (minutes).
Propagation (xLogR)..................  15.....................  15.....................  15
Distance of source level measurement   10.....................  10.....................  10
 (meters).
----------------------------------------------------------------------------------------------------------------


                                   Table 7--Level A Harassment (PTS) Isopleths
----------------------------------------------------------------------------------------------------------------
                                                          PTS Isopleth distance (meters)
                                 -------------------------------------------------------------------------------
            Activity                                                                  Phocid          Otariid
                                    LF cetacean     MF cetacean     HF cetacean      pinniped        pinniped
----------------------------------------------------------------------------------------------------------------
24'' Steel Pipe Pile Impact                881.2            31.3         1,049.7         * 471.6            34.3
 Installation...................
24'' Steel Pipe Vibratory                   14.2             1.3            21.0             8.6             0.6
 Installation...................
24'' Steel Pipe Vibratory                    5.6             0.5             8.3             3.4             0.2
 Removal........................
24'' Timber Pile Removal                     1.4             0.1             2.1             0.9             0.1
 Vibratory......................
----------------------------------------------------------------------------------------------------------------


[[Page 38241]]

Level B Harassment

    Utilizing the practical spreading loss model, the Corps determined 
underwater noise will fall below the behavioral effects threshold of 
160 dB and 120 dB rms for marine mammals at the distances shown in 
Table 8 with corresponding ensonified areas.

                  Table 8--Level B Harassment Isopleths
------------------------------------------------------------------------
                                             Isopleth     Isopleth  area
                Activity                   distance  (m)     (km\2\) *
------------------------------------------------------------------------
24'' Steel Pipe Pile Impact Installation           1,000             3-4
24'' Steel Pipe Vibratory Installation..           5,412           64-73
24'' Steel Pipe Vibratory Removal.......           5,412           64-73
24'' Timber Pile Removal Vibratory......           1,359         0.6-0.7
------------------------------------------------------------------------
* The lower limit represents the isopleth area for the pile dike at RM
  4.01, which has a slightly smaller area due to land impedances. The
  upper limit of the range is the calculated isopleth area for the pile
  dike at RM 6.37.

Marine Mammal Occurrence and Take Calculation and Estimation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations. Potential exposures to impact pile driving, vibratory 
pile driving and vibratory pile removal were estimated using group size 
estimates and local observational data. As previously stated, take by 
Level B harassment as well as small numbers of take by Level A 
harassment will be will be considered for this action. Take by Level B 
and Level A harassment are calculated differently for some species 
based on monthly or daily sightings data and average group sizes within 
the action area using the best available data. Take by Level A 
harassment is being proposed for two species where the Level A 
harassment isopleths are very large during impact pile driving (harbor 
porpoise and harbor seal). Distances to Level A harassment thresholds 
for other project activities (vibratory pile driving/removal) are 
considerably smaller compared to impact pile driving, and mitigation is 
expected to avoid Level A harassment from these other activities.

Cetaceans

Harbor Porpoise
    Harbor porpoises are regularly observed in the oceanward waters 
near the MCR 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). The 2016 monitoring report indicated that there 
were sightings of a total of 6 porpoises during 5 sighting events 
(Grette Associates, 2016) while none were recorded as part of the 2017 
LOA monitoring report. All of the porpoises described in the 2016 
report were solitary except for one pod of two animals. While porpoises 
generally occur in groups of 2-3 or larger, most sightings contained in 
the report were of solitary animals. Therefore, for the purposes of 
this proposed IHA, NMFS will conservatively assume a sighting rate of 
one animal per day.
    There are 3 days of vibratory removal of timber piles so we will 
assume all sightings are equivalent to takes by Level B harassment. 
Both impact and vibratory driving will occur on 18 days. We will assume 
all of these are by Level B harassment due to the larger Level B 
monitoring zone during vibratory driving activities. Due to their 
cryptic behavior, it is plausible that during the 20 days of impact 
only driving porpoises could enter into the shutdown zone without being 
detected by PSOs and remain long enough to experience PTS. NMFS will 
assume that a smaller subset of the 20 expected animals (one per day) 
will enter into the PTS zone for a period of time that would result in 
PTS. We will conservatively assume that every other day an animal would 
enter into the PTS zone. Therefore, NMFS proposes to authorize 10 takes 
of harbor porpoise by Level A harassment and 21 takes by Level B 
harassment.

Pinnipeds

    Take calculations for Steller sea lions, California sea lions, and 
harbor seals are estimated using abundance estimates from the South 
Jetty recorded by the Washington Department of Fish and Wildlife (WDFW) 
between 2000 and 2014. The South Jetty is approximately four kilometers 
to the south of Sand Island. The Level B harassment area includes the 
entirety of the South Jetty where pinnipeds haul out. In order to 
estimate take, the average number of animals seen for the months of 
September, October, and November was used a basis for overall pinniped 
abundance as shown in Table 9. Since there was no data available for 
harbor seals during those three months, the December average was used 
to represent the average during the previous three months. We assumed 
animals counted at the South Jetty comprised the majority of pinnipeds 
present in the Lower Columbia River west of Interstate 101 between 
September and November. This total area, including the jetties, was 
approximately 275 km\2\. We calculated the density of each pinniped 
species per km\2\, then multiplied by the area of the harassment zone 
and number of workdays anticipated at each pile dike (Table10). These 
estimates likely represent take of the same individuals over multiple 
days throughout the construction period. Therefore, the take estimate 
serves as a good estimate of instances of take, but is likely an 
overestimate of individuals taken.
    NMFS proposes to establish a 100-m shutdown zone and 475-m Level A 
harassment zone for harbor seals during impact pile driving activities. 
If a 475-m shutdown zone is adopted for harbor seals to avoid take by 
Level A harassment it was felt that there may be a high shutdown rate 
since harbor seals have been known to approach active construction 
sites. This would negatively impact the construction schedule and 
prolong the duration of heightened underwater noise levels. While the 
likelihood of this type of behavior by seals is unknown in the vicinity 
of the project area, authorizing limited take by Level A harassment 
should reduce the chances of unscheduled shutdown due to incursion of 
harbor seals into the delineated PTS zone.

[[Page 38242]]



                    Table 9--Average Number of Pinnipeds per Month on South Jetty, 2000-2014
----------------------------------------------------------------------------------------------------------------
                                                                  Avg. number of  Avg. number of  Avg. number of
                              Month                                 Steller sea   California sea   harbor seals/
                                                                    lions/month     lions/month        month
----------------------------------------------------------------------------------------------------------------
September.......................................................             209             249  ..............
October.........................................................             384             508  ..............
November........................................................           1,663           1,214  ..............
December........................................................  ..............  ..............              57
Construction Period Average.....................................             752             657              57
----------------------------------------------------------------------------------------------------------------
Source: Data from Washington Department of Fish and Wildlife 2014.


                                         Table 10--Estimated Level B and Level A Take Calculations for Pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Level B
                                      Density                             Level B      Isopleth   Take/day   Take/day    Total      Total     Estimated
             Species                 (animals/       Activity type     Isopleth area   area RM    RM 4.01    RM 6.37    take RM    take RM   total takes
                                      km\2\)                              RM 4.01        6.37                             4.01       6.37     (Level B)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stellar Sea lion................            2.73  Impact                           3          4       8.19      10.92         82        109        3,563
                                                   Installation \1\.
                                                  Vibratory                       64         73     174.72     199.29       1572       1794
                                                   Installation/
                                                   Removal \2\.
                                                  Timber Vibratory               0.6        0.7       1.64       1.91          2          3
                                                   Removal \3\.                                                             1657       1906
--------------------------------------------------------------------------------------------------------------------------------------------------------
California Sea lion.............            2.39  Impact                           3          4       7.17       9.56         72         96        3,119
                                                   Installation.
                                                  Vibratory                       64         73     152.96     174.47       1377       1570
                                                   Installation/
                                                   Removal.
                                                  Timber Vibratory               0.6        0.7       1.43       1.67          2          3
                                                   Removal.                                                                 1450       1668
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor Seal (Level B)...........            0.21  Impact                           3          4       0.61        0.5          6          5          270
                                                   Installation.
                                                  Vibratory                       64         73      13.44      15.33        121        138
                                                   Installation/
                                                   Removal.
                                                  Timber Vibratory               0.6        0.7       0.13       0.15          0          0
                                                   Removal.                                                                  127        143
---------------------------------                -------------------------------------------------------------------------------------------------------
                                                                          Level A      Level A    Take/day   Take/day    Total      Total
                                                                       Isopleth area   Isopleth   RM 4.01    RM 6.37    Take RM    Take RM
                                                                          RM 4.01      area RM                            4.01       6.37
                                                                                         6.37
                                                 -------------------------------------------------------------------------------------------------------
Harbor Seal (Level A)                             Impact                         0.8        0.9       0.15       0.11          2          1  ...........
                                                   Installation.                                                                                       3
                                                                                                                                               (Level A)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Assumes 10 days each at RM 4.01 and RM 6.37 for all pinniped species.
\2\ Assumes 9 days each at RM 4.01 and RM 6.37 for all pinniped species.
\3\ Assumes 1.5 days each at RM 4.01 and RM 6.37 for all pinniped species.

    Table 11 illustrates the stocks NMFS proposed to authorize for 
take, the numbers proposed for authorization, and the percentage of the 
stock taken.

        Table 11--Level A and Level B Harassment Take Estimates for the Sand Island Pile Dikes Test Piles
----------------------------------------------------------------------------------------------------------------
                                                                                       Stock       Percentage of
                     Species                       Level A take    Level B take      abundance      stock taken
----------------------------------------------------------------------------------------------------------------
Harbor porpoise.................................              10              21          21,487             0.1
California Sea Lion.............................  ..............           3,119         296,750             1.1
Stellar Sea Lion................................  ..............           3,563          61,746             5.8
Harbor Seal.....................................               3             270          24,732             1.1
----------------------------------------------------------------------------------------------------------------

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 such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting such 
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, we 
carefully consider 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

[[Page 38243]]

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, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    In addition to the measures described later in this section, the 
Corps must employ the following standard mitigation measures:
     Conduct briefings between construction supervisors and 
crews and the marine mammal monitoring team prior to the start of all 
pile driving activity, and when new personnel join the work, to explain 
responsibilities, communication procedures, marine mammal monitoring 
protocol, and operational procedures;
     For in-water heavy machinery work other than pile driving/
removal (e.g., standard barges, tug boats), if a marine mammal comes 
within 25 m, operations shall cease and vessels shall reduce speed to 
the minimum level required to maintain steerage and safe working 
conditions. This type of work could include the following activities: 
(1) Movement of the barge to the pile location; or (2) positioning of 
the pile on the substrate via a crane (i.e., stabbing the pile);
     Work may only occur during daylight hours, when visual 
monitoring of marine mammals can be conducted;
     For any marine mammal species for which take by Level B 
harassment has not been requested or authorized, in-water pile 
installation/removal will shut down immediately when the animals are 
sighted;
     If take by Level B harassment reaches the authorized limit 
for an authorized species, pile installation will be stopped as these 
species approach the Level B harassment zone to avoid additional take 
of them.
    Establishment of Shutdown Zones and Level A Harassment Zones--For 
all pile driving/removal and activities, the Corps establish a shutdown 
zone. The purpose of a shutdown zone is generally to define an area 
within which shutdown of activity would occur upon sighting of a marine 
mammal (or in anticipation of an animal entering the defined area). 
Shutdown zones will vary based on the type of driving/removal activity 
type and by marine mammal hearing group, (See Table 10). Here, shutdown 
zones are larger than the calculated Level A harassment isopleth shown 
in Table 7, except for harbor seals during impact driving when a 100-m 
shutdown zone and a 475-m Level A harassment zone will be visually 
monitored. The largest shutdown zones are generally for low frequency 
and high frequency cetaceans. The placement of (PSOs) during all pile 
driving/removal activities (described in detail in the Proposed 
Monitoring and Reporting Section) will ensure that the entirety of all 
shutdown zones are visible during pile installation.

                               Table 12--Shutdown Zones During Project Activities
----------------------------------------------------------------------------------------------------------------
                                                                 Distance (meters)
                                 -------------------------------------------------------------------------------
            Activity                                                                  Phocid          Otariid
                                    LF cetacean     MF cetacean     HF cetacean      pinniped        pinniped
----------------------------------------------------------------------------------------------------------------
24'' Steel Pipe Pile Impact                  890              35           1,050             100              35
 Installation...................
24'' Steel Pipe Vibratory                     25              25              25              25              25
 Installation...................
24'' Steel Pipe Vibratory                     25              25              25              25              25
 Removal........................
24'' Timber Pile Removal                      25              25              25              25              25
 Vibratory......................
----------------------------------------------------------------------------------------------------------------

    Establishment of Monitoring Zones for Level B Harassment--The Corps 
will establish monitoring zones, based on the Level B harassment zones 
which are areas where SPLs are equal to or exceed the 160 dB rms 
threshold for impact driving and the 120 dB rms threshold during 
vibratory driving/removal. 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 cease of 
activity should the animal enter the shutdown zone. Distances to the 
Level B harassment zones are depicted in Table 13.

     Table 13--Distances to Level B Harassment Zones During Project
                               Activities
------------------------------------------------------------------------
                       Activity                          Distance  (m)
------------------------------------------------------------------------
24'' Steel Pipe Pile Impact Installation.............              1,000
24'' Steel Pipe Vibratory Installation...............              5,420
24'' Steel Pipe Vibratory Removal....................              5,420
24'' Timber Pile Removal Vibratory...................              1,360
------------------------------------------------------------------------

    Soft Start--The use of a soft-start procedure are believed 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 
will be required to provide an initial set of strikes from the hammer 
at reduced percent energy, each strike followed by no less than a 30-
second waiting period. This procedure will be conducted a total of 
three times before impact pile driving begins. Soft Start is not 
required during vibratory pile driving and removal activities. A soft 
start must be implemented at the start of each day's impact pile 
driving and at any time following cessation of impact pile driving for 
a period of thirty minutes or

[[Page 38244]]

longer. If a marine mammal is present within the Level A harassment 
zone, soft start will be delayed until the animal leaves the Level A 
harassment zone. Soft start will begin only after the PSO has 
determined, through sighting, that the animal has moved outside the 
Level A harassment zone. If a marine mammal is present in the Level B 
harassment zone, soft start may begin and a Level B take will be 
recorded. Soft start up may occur when these species are in the Level B 
harassment zone, whether they enter the Level B zone from the Level A 
zone or from outside the monitoring area.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving of 30 
minutes or longer occurs, PSOs will observe the shutdown and monitoring 
zones for a period of 30 minutes. The shutdown zone will be 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 Level B harassment 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 even 
if visibility becomes impaired within the Level B harassment zone. When 
a marine mammal permitted for take by Level B harassment is present in 
the Level B harassment zone, piling activities may begin and take by 
Level B will be recorded. As stated above, if the entire Level B 
harassment zone is not visible at the start of construction, pile 
driving/removal activities can begin. If work ceases for more than 30 
minutes, the pre-activity monitoring of both the Level B harassment and 
shutdown zone will commence.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

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 in the 
proposed action area. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Monitoring 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 
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 thirty minutes.
    There will be at least two PSOs employed during all pile driving/
removal activities. PSO will not perform duties for more than 12 hours 
in a 24-hour period. One PSO would be positioned close to pile driving/
removal activities at the best practical vantage point. A second PSO 
would be vessel-based to provide best coverage of the appropriate Level 
A and Level B harassment zones. If waters exceed a sea-state which 
restricts the observers' ability to make boat-based observations for 
the full Level A shutdown zone (e.g., excessive wind, wave action, or 
fog), impact pile installation will cease until conditions allow 
monitoring to resume. Contractors should ensure compliance with NOAA 
advisories for safe boat operations based on the size of vessel to be 
used by the marine mammal observer.
    As part of monitoring, PSOs would scan the waters using binoculars, 
and/or spotting scopes, and would use a handheld GPS or range-finder 
device to verify the distance to each sighting from the project site. 
All PSOs would be trained in marine mammal identification and behaviors 
and are required to have no other project-related tasks while 
conducting monitoring. In addition, monitoring will be conducted by 
qualified observers, who will 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. Qualified observers are trained and/or experienced 
professionals, with the following minimum qualifications:
     Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the water's surface 
with ability to estimate target size and distance; use of binoculars 
may be necessary to correctly identify the target;
     Independent observers (i.e., not construction personnel);
     Observers must have their CVs/resumes submitted to and 
approved by NMFS;
     Advanced education in biological science or related field 
(i.e., undergraduate degree or higher). Observers may substitute 
education or training for experience;
     Experience and ability to conduct field observations and 
collect data according to assigned protocols (this may include academic 
experience);
     At least one observer must have prior experience working 
as an observer;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;

[[Page 38245]]

     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 must be submitted to NMFS 
within 90 days after the completion of pile driving/removal activities. 
This reports will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the reports must include:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Weather parameters (e.g., percent cover, visibility);
     Water conditions (e.g., sea state, tide state);
     Species, numbers, and, if possible, sex and age class of 
marine mammals;
     Description of any observable marine mammal behavior 
patterns, including bearing and direction of travel and distance from 
pile driving activity;
     Distance from pile driving activities to marine mammals 
and distance from the marine mammals to the observation point;
     Locations of all marine mammal observations;
     An estimate of total take based on proportion of the 
monitoring zone that was observed; and
     Other human activity in the area.
    If no comments are received from NMFS within 30 days, that phase's 
draft final report will constitute the final report. If comments are 
received, a final report for the given phase addressing NMFS comments 
must be submitted within 30 days after receipt of comments. In the 
unanticipated event that the specified activity clearly causes the take 
of a marine mammal in a manner prohibited by the IHAs (if issued), such 
as an injury, serious injury or mortality, the Corps would immediately 
cease the specified activities and report the incident to the Chief of 
the Permits and Conservation Division, Office of Protected Resources, 
NMFS, and the West Coast Regional Stranding Coordinator. The report 
would include the following information:
     Description of the incident;
     Environmental conditions (e.g., Beaufort sea state, 
visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with the Corps to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. The Corps would not be able 
to resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that the Corps discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition as described in the next paragraph), 
the Corps would immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the West Coast Regional Stranding Coordinator. The report would 
include the same information identified in the paragraph above. 
Activities would be able to continue while NMFS reviews the 
circumstances of the incident. NMFS would work with the Corps to 
determine whether modifications in the activities are appropriate.
    In the event that the Corps discovers an injured or dead marine 
mammal and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in these IHAs 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), the Corps would report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, and the West Coast Regional Stranding 
Coordinator, within 24 hours of the discovery. The Corps would provide 
photographs, video footage (if available), or other documentation of 
the stranded animal sighting to NMFS and the Marine Mammal Stranding 
Network.

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 responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), 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's 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 environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    To avoid repetition, our analysis applies to all species listed in 
Table 11, given that NMFS expects the anticipated effects of the 
proposed pile driving/removal to be similar in nature. Where there are 
meaningful differences between species or stocks, or groups of species, 
in anticipated individual responses to activities, impact of expected 
take on the population due to differences in population status, or 
impacts on habitat, NMFS has identified species-specific factors to 
inform the analysis.
    NMFS does not anticipate that serious injury or mortality would 
occur as a result of the Corps' proposed activity. As stated in the 
proposed mitigation section, shutdown zones that equal or exceed Level 
A harassment isopleths shown in Table 12 will be implemented. Take by 
Level A harassment is proposed for authorization for some species

[[Page 38246]]

(harbor seals, harbor porpoises) to account for the slight possibility 
that these species escape observation by the PSOs within the Level A 
harassment zone. Further, any take by Level A harassment is expected to 
arise from, at most, a small degree of PTS 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. 
Additionally, 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.
    Behavioral responses of marine mammals to pile driving and removal 
at the proposed test piles project sites are e expected to be mild, 
short term, and temporary. Marine mammals within the Level B harassment 
zone may not show any visual cues they are disturbed by activities or 
they could become alert, avoid the area, leave the area, or display 
other mild responses that are not observable such as changes in 
vocalization patterns. Given the short duration of noise-generating 
activities (between 6-41 days over 3-month period), any harassment 
would be likely be intermittent and temporary. Additionally, many of 
the species occurring near the MCR or in the Columbia River estuary 
would only be present temporarily based on seasonal patterns or during 
transit between other habitats. These temporarily present species would 
be exposed to even smaller periods of noise-generating activity, 
further decreasing the impacts.
    In addition, for all species there are no known biologically 
important areas (BIAs) within the MCR or Columbia River estuary and 
there is no ESA-designated marine mammal critical habitat. The estuary 
represents a very small portion of the total available habitat to 
marine mammal species.
    More generally, there are no known calving or rookery grounds 
within the project area, but anecdotal evidence from local experts 
shows that marine mammals are more prevalent during spring and summer 
associated with feeding on aggregations of fish. Because the Corps' 
activities would occur in the fall months, the project area represents 
a small portion of available foraging habitat, and the duration of 
noise-producing activities relatively is short, meaning impacts on 
marine mammal feeding for all species should be minimal.
    Any impacts on marine mammal prey that would occur during the 
Corps' proposed activity would have at most short-terms effects on 
foraging of individual marine mammals, and likely no effect on the 
populations of marine mammals as a whole. Therefore, indirect effects 
on marine mammal prey during the construction are not expected to be 
substantial, and these insubstantial effects would therefore be 
unlikely to cause substantial effects on marine mammals.
    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 the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality is anticipated or authorized;
     The Corps would implement mitigation measures including 
soft-starts for impact pile driving and shutdown zones that exceed 
Level A harassment zones for authorized species, except for harbor 
seals which will help to ensure that take by Level A harassment is at 
most a small degree of PTS;
     Anticipated incidents of Level B harassment consist of, at 
worst, temporary modifications in behavior;
     There are no BIAs within the MCR and Columbia River 
estuary or other known areas of particular biological importance to any 
of the affected stocks are impacted by the activity;
     The project area represents a very small portion of the 
available foraging area for all marine mammal species and anticipated 
habitat impacts are minimal; and
     The required mitigation measures (e.g., shutdown zones, 
soft-start) are expected to be effective in reducing the effects of the 
specified activity.
    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 above, only small numbers of incidental take may be 
authorized under Sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. Additionally, other qualitative 
factors may be considered in the analysis, such as the temporal or 
spatial scale of the activities.
    Table 11 in the Marine Mammal Occurrence and Take Calculation and 
Estimation section, present the number of animals that could be exposed 
to received noise levels that may result in take by Level A harassment 
or Level B harassment from the Corps' proposed activities. Our analysis 
shows that 6 percent or less of the best population estimates of each 
affected stock could be taken. Additionally, the proposed test piles 
project is located near the pinniped haulout at the South Jetty. 
Therefore, it is likely that many of these takes will be repeated takes 
of the same animals over multiple days. As such, the take estimate 
serves as a good estimate of instances of take, but is likely an 
overestimate of individuals taken, so actual percentage of stocks taken 
would be even lower.
    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 will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Endangered Species Act (ESA)

    No incidental take of ESA-listed species is proposed for 
authorization or expected to result from this activity. Therefore, NMFS 
has determined that formal consultation under section 7 of the ESA is 
not required for this action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the Corps for conducting test pile installation and 
removal, near the MCR, from one year from the date of issuance, 
provided the previously mentioned mitigation, monitoring, and

[[Page 38247]]

reporting requirements are incorporated. A draft of the proposed IHA 
can be found at https://www.fisheries.noaa.gov/permit/incidental-take-
authorizations-under-marine-mammal-protection-act.

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 Sand 
Island Pile Dike System Test Piles Project. We also request at this 
time 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.
    On a case-by-case basis, NMFS may issue a one-year IHA renewal with 
an additional 15 days for public comments when (1) another year of 
identical or nearly identical activities as described in the Specified 
Activities section of this notice is planned or (2) the activities as 
described in the Specified Activities section of this notice would not 
be completed by the time the IHA expires and a Renewal would allow for 
completion of the activities beyond that described in the Dates and 
Duration section of this notice, provided all of the following 
conditions are met:
     A request for renewal is received no later than 60 days 
prior to expiration of the current IHA;
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal 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 
because only a subset of the initially analyzed activities remain to be 
completed under the Renewal);
    (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; and
     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 31, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2019-16706 Filed 8-5-19; 8:45 am]
 BILLING CODE 3510-22-P