Take of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the North Jetty Maintenance and Repairs Project, Coos Bay, Oregon, 56781-56803 [2019-23081]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 84, Number 205 (Wednesday, October 23, 2019)]
[Notices]
[Pages 56781-56803]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-23081]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XR048


Take of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to the North Jetty Maintenance and Repairs 
Project, Coos Bay, Oregon

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

ACTION: Notice; two proposed incidental harassment authorizations; 
request for comments on proposed authorizations and possible renewals.

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SUMMARY: NMFS has received a request from the U.S. Army Corps of 
Engineers (USACE) for two authorizations to take marine mammals 
incidental to the pile driving and removal activities over two years 
associated with the Coos Bay North Jetty maintenance and repairs 
project. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is 
requesting comments on its proposal to issue two incidental harassment 
authorizations (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-year renewals 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 November 
22, 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: Stephanie Egger, 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. Under the MMPA, ``take'' is defined as meaning to harass, 
hunt, capture, or kill, or attempt to harass, hunt, capture, or kill 
any marine mammal.
    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.
    These actions are 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 these proposed IHAs qualifies to be categorically 
excluded from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA requests.

Summary of Request

    On March 18, 2019, NMFS received a request from USACE for two IHAs 
to take marine mammals incidental to vibratory pile driving and removal 
associated with the North Jetty maintenance and repairs project, Coos 
Bay, Oregon over the course of two years with pile installation 
occurring during Year 1 and pile removal occurring during Year 2. The 
application was deemed adequate and

[[Page 56782]]

complete on September 10, 2019. The USACE's request is for take of a 
small number of seven species of marine mammals by Level B harassment 
only. Neither USACE nor NMFS expects injury, serious injury or 
mortality to result from this activity and, therefore, IHAs are 
appropriate. The IHAs, if issued, will be effective from September 1, 
2020 through August 31, 2021 for pile driving installation (Year 1) and 
from July 1, 2022 through June 30, 2023 for pile removal (Year 2). The 
USACE, in coordination with the Oregon Department of Fish and Wildlife 
(ODFW) and NMFS' Northwest Region, proposes to conduct pile driving and 
removal October 1st through February 15th and June 1st and July 31st to 
minimize effects to listed salmonids. Adherence to the in-water work 
window is part of USACE's Endangered Species Act (ESA) consultation 
under Standard Local Operating Procedures for Endangered Species 
(SLOPES) to administer actions authorized or carried out by the USACE 
in Oregon (SLOPES IV In-water Over-water Structures). The ODFW will 
make the final determination of the in-water work window.

Description of Proposed Activity

Overview

    The USACE is proposing to repair critically damaged sections of the 
North Jetty, monitor erosion, and to maintain stable deep-draft 
navigation through the entrance into Coos Bay. Repair activities 
completed now will reduce the risk of jetty failure or a potential 
breach of the Coos Bay North Spit (CBNS). The USACE maintains this 
jetty system and navigational channels, and is currently proposing 
major repair and rehabilitation of the North Jetty. As part of its 
mission to build and maintain navigation facilities, the USACE also 
continues to maintain ownership of CBNS land to support jetty 
monitoring, ensure evaluation access, and to provide construction 
staging and stockpile areas in the event jetty maintenance or 
navigation repairs are needed. Work associated with the project may 
occur year-round beginning in September 2020. The USACE proposes to use 
vibratory pile driving/removal for the Material Off-loading Facility 
(MOF) portion of the project using 30-inch (in) steel piles and 24-in 
AZ sheet piles OR 12-in H piles. The use of AZ-sheets versus H-piles 
will be per the contractor's discretion, largely based on site 
conditions, material availability, and cost.

Dates and Duration

    The USACE currently anticipates that construction for North Jetty 
maintenance and repair project will occur over two years. The IHA 
application is requesting take that may occur from the pile driving 
activities in the first year (September 1, 2020 through August 31, 
2021) and from pile removal activities in the second year of pile 
driving activities (July 1, 2022 through June 30, 2023). The USACE 
proposes to complete pile driving activities between October 1st 
through February 15th and June 1st through July 31st each year to 
protect salmonids.
    The USACE estimates vibratory pile driving may occur over a 1-4 
month time period each year but likely would take one month for 
installation (Year 1) and one month for removal (Year 2). There would 
be an estimate of 7 days of noise expose during pile driving for each 
type of pile (i.e., and 30-in steel piles and 24-in AZ sheet piles OR 
12-in H piles) for a total of 14 days of pile driving activity each 
year. Pile driving may occur up to 6 hours per day depending on the 
pile type.

Specific Geographic Region

    Coos Bay is an approximately 55.28 km\2\ estuary located in Coos 
County on the Oregon coast, approximately 200 miles south of the 
Columbia River. The bay provides a harbor- and water-dependent economy 
for the local and state community and, as the second largest estuary in 
Oregon (14,000 acres), the largest located entirely within state 
borders (Hickey and Banas 2003, Arneson 1975), and is an important 
biological resource. It is considered the best natural harbor between 
San Francisco Bay, California and the Puget Sound, Washington. The 
average depth of the Coos estuary is 4 m (13 ft). The Coos estuary 
exhibits the typical features of a drowned river valley estuary type. 
It features a V-shaped cross section, a relatively shallow and gently 
sloping estuary bottom, and a fairly uniform increase in depth from the 
upper, river-dominated part of the estuary toward the mouth. Large 
expanses of intertidal sand and mud flats complement channels, eelgrass 
beds, vegetated marshes, and swamps to provide a diversity of estuarine 
habitats.
    The entrance to the Coos Bay estuary and navigation channel lies 
between Coos Head and the Coos Bay North Spit (CBNS) (see Figure 1-1 of 
the application). The Coos Bay north and south jetties stabilize a 1-
mile long, 47[hyphen]foot deep channel. Channel depth decreases to 
approximately 37 feet at RM 1 and extends 15 miles upstream where it 
runs adjacent to the cities of Charleston, North Bend, and Coos Bay.
    The CBNS is a large isolated peninsula about 15 miles from downtown 
Coos Bay; supporting unique coastal habitats. The USACE parcel (see 
Figure 1-2 of the application) runs north from the boundary of the 
North Jetty, to the southern boundary of land owned by the U.S. Bureau 
of Land Management (BLM). It is bound by the Pacific Ocean to the west, 
which includes South Beach (the beach between the North Jetty and the 
FAA towers as shown), and by the Log-Spiral Bay (LSB) and Coos Bay to 
the east. The extent of the North Jetty repairs and staging areas of 
the overall project area are shown below in Figure 1.

[[Page 56783]]

[GRAPHIC] [TIFF OMITTED] TN23OC19.001

Detailed Description of Specific Activity

    The purpose of the proposed action is to repair critically damaged 
sections of the North Jetty in order to maintain stable deep-draft 
navigation through the entrance into Coos Bay and to prevent breaching 
of the CBNS. Completing the proposed repair activities now will reduce 
the risk of future jetty failure. Progressive damages to the North 
Jetty system over the last 20 years have resulted in an emergency 
repair action in 2002 and an interim repair in 2008. The proposed major 
maintenance of the Coos Bay North Jetty is critical to keeping the 
river and harbor open to deep-draft navigation and to sustaining 
important navigation-related components of local and state economies.
    The proposed activities would include repair activities for three 
main jetty components: The jetty head, root, and trunk. Repair 
activities also require re-establishment and repair of the following 
three temporary construction features including the MOF, upland staging 
areas and road turn-outs to facilitate equipment and material delivery. 
Removal and site restoration for each of the temporary construction 
features is proposed.
    The majority of proposed jetty repairs will be completed within the 
existing authorized footprint of the jetty structure, returning 
specified sections to pre-erosional conditions. However, the length of 
the final repaired jetty (8,425 feet (ft)) will be shorter than its 
originally authorized footprint length of 9,600 ft. The jetty head 
stabilizes the oceanward end of the jetty structure and is exposed to 
the most severe loading. The jetty trunk connects the jetty head to the 
jetty root and transitions from a jetty reach exposed to both ocean-
side and channel-side loading, to the root, which is primarily loaded 
from the channel-side. Proposed repair elements may include some minor 
areas that occur outside of the existing jetty footprint, but are 
necessary to maintain jetty function.
    [ssquf] Repair of the jetty root entails rebuilding up to 1,600 ft 
of the jetty root. Toe protection around the tip of the reconstructed 
section would be completed to compensate for accelerated ebb-tidal 
flows caused by the reconstructed root. This protection could extend 
beyond the area of the existing relic jetty root.
    [ssquf] Construction of a rubble-mound jetty head (located 
shoreward of the originally authorized North Jetty head). While it is 
expected that the vast majority of the head construction will remain on 
the relic stone base, there may be some small increase in footprint to 
ensure a stable jetty head design.
    The USACE proposes to rebuild sections of the jetty root where the 
structure has deteriorated at or below the water line. The jetty head 
and trunk require extensive repairs, but not to the same extent as the 
jetty root, which has not been repaired since the original 
construction. Optional repairs to the jetty root could provide 
additional stability to LSB and prevent further

[[Page 56784]]

erosion. The optional repairs to the jetty trunk could place larger 
stone atop sections that were previously addressed with slightly 
smaller stone during an interim repair. Each of these optional repairs 
would be contingent on funding availability.
Construction Staging Areas
    Jetty repairs and associated construction elements require 
additional areas for activities involving equipment and supply staging 
and storage, parking areas, access roads, scales, general yard 
requirements, and jetty stone stock pile areas. Staging areas are 
required to store materials, equipment and tools, field offices, turn 
and maneuver trucks, and to provide parking for contractors.
    There are three proposed staging areas for the Proposed Action: The 
Overland Delivery Staging Area (ODSA, up to about 10 acres), the North 
Jetty Staging Area (NJSA, up to 20 combined acres from three alternate 
staging areas), and the MOF Staging Area (up to 2.5 acres) (see Figure 
1-3 of the application). The MOF Staging Area is where all pile driving 
and removal activities will occur. The ODSA was used previously for the 
2008 North Jetty Interim Repair Project. The MOF Staging Area, also 
previously used and located upland of the MOF itself, would be 
necessary to accommodate stockpile and transfer of jetty stone from 
barges to transport vehicles prior to delivery to the NJSA. The NJSA 
will be a combination of areas; either approximately 20 acres near the 
jetty root, on top of the LSB sand placement area, or a jetty root 
staging area (1.5 acres) and up to an additional 18.5 acres to be 
chosen by the Contractor from the available Alternate Staging Area 
locations shown on the plans.
    Staging area equipment would include a crane or excavator for 
transferring large stones from the highway-transport vehicles to heavy-
duty off-road vehicles, or from a barge to heavy-duty off-road 
vehicles, an excavator, front-end loaders, and bulldozers. All of the 
stockpile areas would accommodate storage of a range of different sized 
jetty stone and other rock and gravel construction materials throughout 
the year. Construction of each upland staging area would require 
vegetation clearing and site grading, which would be followed by 
restoration at the completion of construction.
North Jetty Major Maintenance and Repairs
    Most of the proposed jetty stone placement work would use land-
based equipment for construction of the repair and modifications to the 
North Jetty. The majority of the work is expected to be conducted from 
on top of the jetty using an excavator or a crane. Where appropriate, 
there may also be rework and reuse of the existing relic and jetty 
prism stone. Most of the proposed stone placement would occur on 
existing relic stone that formed the original jetty. The prism 
footprint could increase in width compared to the existing prism by 
about 10 ft along the length of the proposed repair sections. During 
new stone placement, there is a chance of stone slippage down the slope 
of the jetty. This is only a remote possibility given the size of the 
rocks. Additionally, dropping armor stone from a height greater than 2 
ft would be prohibited, further minimizing the risk of stone slippage. 
The length of the repaired jetty would remain shorter than its 
originally authorized footprint length.
    The full width of the repaired jetty crest would double as a 
``jetty crest haul road'' that allows construction equipment to access 
and reach the entire jetty construction areas (i.e., crest, slope, and 
toe). As described in Table 1-2 of the application, up to three 
turnouts would also be required every 300 to 500 ft along the length of 
the jetty and parallel to the jetty crest haul road for safety purposes 
(allows for vehicle and equipment passing and turns while on the 
jetty). The footprint of repairs would not extend substantially beyond 
the extent of relic jetty stone (possibly up to 10 ft on either side).
Material Offloading Facility (MOF)
    The MOF will be constructed from the land waterward using land-
based equipment. The MOF will provide vehicle access to/from the shore. 
The MOF could either be a simplified design of singular pipe piles for 
mooring a barge with spuds as a dock face, or a more complicated MOF 
design with piles supporting mooring dolphins with H or Z-piles to help 
retain material. In either case, pilings will be installed by barge 
using vibratory pile driving methods. Figure 1-4 of the application 
provides a basic overview of potential MOF elements, though the final 
configuration of pilings and specifications within the broader scope 
will be determined by the contractor. Fill material to construct the 
MOF could be obtained from maintenance dredging activities that occur 
annually in the Federal Navigation Channel, from dredging at the MOF 
site, or from other suitable sources, similar to those that provide the 
armor stone and gravel materials for the Project. Any imported material 
will be obtained from a clean and permitted source, suitable for in-
water placement. Initial dredging of up to about 24,000 cubic yards may 
be required at the MOF to reach draft depth for the delivery barges. 
This activity will most likely be completed by mechanical dredge (e.g., 
clamshell). Dredged material from the MOF site will be tested for 
contaminants, prior to dredging, following standard USACE and U.S. 
Environmental Protection Agency procedures. If clean, material will be 
side-cast or used to supplement MOF construction. If not suitable for 
ocean placement, dredged material will be transported to a suitable and 
certified upland facility. Maintenance dredging at the MOF will occur 
throughout construction to maintain depths needed for delivery vessels.
    Additional details on the project construction elements can be 
found in Section 1 of the project application. The USACE has not 
requested, and NMFS does not propose to issue, take from any activities 
other than from vibratory pile driving and removal for the MOF.
    The type and amount of piles associated with the project are 
provided in Table 1.

Table 1--Pile Driving (Year 1) and Removal (Year 2) Associated With the MOF of the North Jetty Repairs and Maintenance Project. The Same Number of Piles
                                                       Driven in Year 1 Will Be Removed in Year 2
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                                                                 Total number    Total number   Maximum number  Maximum number
                                                                of piles to be  of piles to be     of piles        of piles
              Pile type                          Size            driven (year    removed (year  driven per day    removed per         Driving type
                                                                      1)              2)           (year 1)      day (year 2)
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Steel Pipe Pile......................  30-inch................              24              24               6               6  Vibratory.
Steel H Pile.........................  12-in..................              40              40              25              25  Vibratory.
Steel AZ Sheet.......................  24-in..................             100             100              25              25  Vibratory.
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[[Page 56785]]

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

Description of Marine Mammals in the Area of Specified Activities

    Systematic marine mammal surveys in Coos Bay are limited; 
therefore, the USACE relied on two multi-day AECOM surveys of Coos Bay, 
Oregon Department of Fish and Wildlife (ODFW), and anecdotal reports to 
better understand marine mammal presence in Coos Bay and in support of 
the IHA application. Seven marine mammal species comprising seven 
stocks have the potential to occur within Coos Bay during the project.
    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 
around Coos Bay 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 and Alaska 2018 SARs (e.g., Carretta et al., 2018; 
Muto et al., 2018). All values presented in Table 2 are the most recent 
available at the time of publication and are available in the 2018 SARs 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports).

                                                 Table 2--Marine Mammals Occurrence in the Project Area
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                                                                                         ESA/MMPA status;    Stock abundance  (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
    Blue whale......................  Balaenoptera m.          Eastern North Pacific    E,D;Y               1,647 (0.07; 1,551;           2.3       >=19
                                       musculus.                Stock.                                       2011).
    Humpback whale..................  Megaptera novaeangliae.  California/Oregon/       E,D;Y               2,900 (0.05; 2,784;          16.7     >=40.2
                                                                Washington Stock.                            2014).
Family Eschrichtiidae:
    Gray whale......................  Eschrichtius robustus..  Eastern North Pacific..  N, N                26,960 (0.05, 25,849,         801        139
                                                                                                             2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer Whale....................  Orcinus orca...........  West Coast Transient...  N, N                243 (-, 243, 2006) \4\        2.4          0
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Northern CA/Southern OR  N, N                35,769 (0.52, 23,749,         475      >=0.6
                                                                                                             2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Northern elephant sea...........  Mirounga angustirostris  California breeding....  N, N                179,000 (n/a, 81,368,       4,882        8.8
                                                                                                             2010).
    Steller sea lion................  Eumetopias jubatus.....  Eastern U.S............  N, N                41,638 (-, 41,638,          2,498        108
                                                                                                             2015).
    California sea lion.............  Zalophus californianus.  U.S....................  N, N                257,606 (n/a, 233,515,     14,011       >320
                                                                                                             2014).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  Oregon/Washington Coast  N, N                24,732 (0.12, -, 1999)        unk        unk
                                                                                                             \5\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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.
\3\ These values, found in NMFS' 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.
\4\ The minimum population estimate (NMIN) for the West Coast Transient stock of killer whales is derived from mark-recapture analysis for West Coast
  transient population whales from the inside waters of Alaska and British Columbia of 243 whales (95 percent probability interval = 180-339) in 2006
  (DFO 2009), which includes animals found in Canadian waters.
\5\ Because the most recent abundance estimate is >8 years old (1999), there is no current estimate of abundance available for this stock. However, for
  purposes of this analysis, we apply the previous abundance estimate, corrected for animals missed in the water as described in Carretta et al. (2014)
  of 24,732.


[[Page 56786]]

    All species that could potentially occur in the proposed survey 
areas are included in Table 2. Humpback whales (Megaptera novaeangliae) 
and blue whales (Balaenoptera musculus musculus) are not uncommon along 
the Oregon coast, however, they are unlikely to enter Coos Bay and be 
affected by construction noise. Given these considerations, the 
temporary duration of potential pile driving, and noise isopleths that 
would not extend beyond the river mouth, there is no reasonable 
expectation for proposed activities to affect these species and they 
are not discussed further.
    As described below, the remaining seven species comprising seven 
stocks temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur, and we have proposed 
authorizing it.

Gray Whales

    Gray whales are only commonly found in the North Pacific. Genetic 
comparisons indicate there are distinct ``Eastern North Pacific'' (ENP) 
and ``Western North Pacific'' (WNP) population stocks, with 
differentiation in both mtDNA haplotype and microsatellite allele 
frequencies (LeDuc et al. 2002; Lang et al. 2011a; Weller et al. 2013). 
Tagging, photo-identification and genetic studies show that some whales 
identified in the WNP off Russia have been observed in the ENP, 
including coastal waters of Canada, the U.S. and Mexico (Lang 2010; 
Mate et al. 2011; Weller et al. 2012; Urb[aacute]n et al. 2013, Mate et 
al. 2015). However, WNP gray whales are not expected to enter Coos Bay 
and therefore will not be discussed further.
    From 2009 to 2013, researchers attached satellite tags to 35 gray 
whales off the coasts of Oregon and northern California from September 
to December 2009, 2012, and 2013 (Lagerquist et al., 2019). These 
whales are members of the Pacific Coast Feeding Group (PCFG), a subset 
of gray whales in the ENP that feed off the PNW, during summer and 
fall. Tracking periods for the satellite[hyphen]tagged whales in this 
study ranged from 3 days to 383 days. Feeding[hyphen]area home ranges 
for the resulting 23 whales covered most of the near[hyphen]shore 
waters from northern California to Icy Bay, Alaska, and ranged in size 
from 81[thinsp]km\2\ to 13,634[thinsp]km\2\. Core areas varied widely 
in size (11-3,976[thinsp]km\2\) and location between individuals, with 
the highest[hyphen]use areas off Point St. George in northern 
California, the central coast of Oregon, and the southern coast of 
Washington. Tag data indicates whales primarily occupied waters 
predominantly over continental shelf waters less than 10[thinsp]km from 
shore and in depths less than 50[thinsp]m. Gray whales are not known to 
enter Coos Bay; however, they do enter larger bays such as San 
Francisco Bay during their northward and southward migration and 
therefore are included in this analysis.
    Since January 1, 2019, elevated gray whale strandings have occurred 
along the west coast of North America from Mexico through Alaska. This 
event has been declared an Unusual Mortality Event (UME). A UME is 
defined under the MMPA as a stranding that is unexpected; involves a 
significant die-off of any marine mammal population; and demands 
immediate response. As of September 5, 2019, 117 gray whales have 
stranded in the U.S. between Alaska and California with an additional 
10 strandings in Canada and 81 in Mexico. Of the U.S. strandings, six 
of the animals have been found in Oregon. Full or partial necropsy 
examinations were conducted on a subset of the whales. Preliminary 
findings in several of the whales have shown evidence of emaciation. 
These findings are not consistent across all of the whales examined, so 
more research is needed. Threats to gray whales include ship strike, 
fishery gear entanglement, and climate change-related impacts such as 
reduction in prey availability, and increased human activity in the 
Arctic (Carretta et. al., 2019).

Killer Whales

    Killer whales are found throughout the North Pacific. Along the 
west coast of North American, `resident,' transient,' and `offshore' 
ecotypes have overlapping distributions and multiple stocks are 
recognized within that broader classification scheme. The West Coast 
Transient (WCT) Stock includes animals that range from California to 
southern Alaska, and is genetically distinct from other transient 
populations in the region (i.e., Gulf of Alaska, Aleutian Islands, and 
Bering Sea transients and AT1 transients). While not regularly seen in 
Coos Bay, anecdotal accounts by ODFW biologists suggest bachelor pods 
of transient killer whales may be observed in Coos Bay semi-annually. 
In May 2017, a pair of killer whales feeding on what was concluded to 
be a seal were opportunistically observed in Coos Bay (AECOM 2017). The 
whales moved through the estuary northwards past Jordan Cove to the 
Highway 101 Bridge. However, the whales are not known to linger in the 
area and no biologically important habitat for this stock exists in 
Coos Bay.

Harbor Porpoise

    In the Pacific Ocean, harbor porpoise are found in coastal and 
inland waters from Point Conception, California to Alaska and across to 
Kamchatka and Japan (Gaskin 1984). There are several stocks of harbor 
porpoise along the west coast of the U.S. and in inland waterways. 
While harbor porpoise are rare within Coos Bay, if present, animals are 
likely belonging to the Northern California/Southern Oregon stock which 
is delimited from Port Arena, California in the south to Lincoln City, 
Oregon. Use of Coos Bay by this stock is rare.

Northern Elephant Seal

    Northern elephant seals are found occasionally in Oregon either 
resting or molting (shedding their hair) on sandy beaches. Elephant 
seals do not generally breed in Oregon; however, there are a number of 
breeding sites in California such as Ano Nuevo State Reserve. Cape 
Arago State Park, just south of the entrance to Coos Bay, is the only 
spot where northern elephant seals haulout year-around in Oregon. The 
majority of the elephant seals seen in Oregon are sub-adult animals 
that come to shore to molt. Northern elephant seals regularly occur at 
haul-out sites on Cape Arago, approximately 3.7 miles south of the 
entrance to Coos Bay. Scordino (2006) reported total counts (average, 
maximum, minimum) of harbor seal, elephant seal, California sea lion, 
and Steller sea lion at Cape Arago during each month surveyed between 
2002 and 2005. Abundance of elephant seals was low in all months, with 
a maximum of 54 animals reported in May (Scordino 2006). No Northern 
elephant seals have been observed within Coos Bay; however, given their 
close proximity to the mouth of the estuary, they have been included in 
this analysis.

California Sea Lion

    California sea lions are distributed along the North Pacific waters 
from central Mexico to southeast Alaska, with breeding areas restricted 
primarily to island areas off southern California (the Channel 
Islands), Baja California, and in the Gulf of California (Wright et 
al., 2010). There are five genetically distinct geographic populations. 
The population seen in Oregon is the Pacific Temperate stock, which are 
commonly seen in Oregon from September through May (ODFW 2015). The 
approximate growth rate for this species is 5.4 percent annually 
(Caretta et al., 2004).
    Almost all California sea lions in the Pacific Northwest are sub-
adult or adult

[[Page 56787]]

males (NOAA 2008). The occurrence of the California sea lion along the 
Oregon coast is seasonal with lowest abundance in Oregon in the summer 
months, from May to September, as they migrate south to the Channel 
Islands in California to breed. During other times of the year, the 
primary areas where it comes ashore are Cascade Head, Tillamook County; 
Cape Argo, Coos County; and Rouge Reef and Orford Reef in Curry County.
    The California sea lion stock has been growing steadily since the 
1970s. The stock is estimated to be approximately 40 percent above its 
maximum net productivity level (MNPL = 183,481 animals), and it is 
therefore considered within the range of its optimum sustainable 
population (OSP) size (Laake et al., 2018). The stock is also near its 
estimated carrying capacity of 275,298 animals (Laake et al., 2018). 
However, there remain many threats to California sea lions including 
entanglement, intentional kills, harmful algal blooms, and climate 
change. For example, for each 1 degree Celsius increase in sea surface 
temperature (SST), the estimated odds of survival declined by 50 
perfect for pups and yearlings, while negative SST anomalies resulted 
in higher survival estimates (DeLong et al., 2017). Such declines in 
survival are related to warm oceanographic conditions (e.g., El 
Ni[ntilde]o) that limit prey availability to pregnant and lactating 
females (DeLong et al., 2017). Changes in prey abundance and 
distribution have been linked to warm-water anomalies in the California 
Current that have impacted a wide range of marine taxa (Cavole et al., 
2016).
    There were at least eight California sea lions sighted 
opportunistically during the 2017 AECOM surveys (ACEOM, 2017). No pups 
were observed.

Steller Sea Lion

    The Steller sea lion range extends along the Pacific Rim, from 
northern Japan to central California. For management purposes, Steller 
sea lions inhabiting U.S. waters have been divided into two DPS: The 
Western U.S. and the Eastern U.S. The population known to occur within 
the Lower Columbia River is the Eastern DPS. The Western U.S. stock of 
Steller sea lions are listed as endangered under the ESA and depleted 
and strategic under the MMPA. The Eastern U.S. stock (including those 
living in Oregon) was de-listed in 2013 following a population growth 
from 18,000 in 1979 to 70,000 in 2010 (an estimated annual growth of 
4.18 percent) (NOAA 2013). A population growth model indicates the 
eastern stock of Steller sea lions increased at a rate of 4.76 percent 
per year (95 percent confidence intervals of 4.09-5.45 percent) between 
1989 and 2015 based on an analysis of pup counts in California, Oregon, 
British Columbia, and Southeast Alaska (Muto et al., 2017). This stock 
is likely within its OSP; however, no determination of its status 
relative to OSP has been made (Muto et al., 2017).
    Steller sea lions can be found along the Oregon coast year-round 
with breeding occurring in June and July. The southern coast of Oregon 
supports the largest Steller breeding sites in U.S. waters south of 
Alaska, producing some 1,500 pups annually. Near the entrance of Coos 
Bay, Steller sea lions can be found year round at Cape Arago State 
Park. The most recent Steller sea lion survey at Cape Arago was June 
29, 2017, during which ODFW counted 910 non-pup Steller sea lions 
ashore. Steller sea lions may occasionally enter Coos Bay; however, no 
long-term residency patterns have been observed. One Steller sea lion 
was sighted opportunistically during the 2017 AECOM surveys (ACEOM 
2017). No pups were observed.

Harbor Seal

    Harbor seals inhabit coastal and estuarine waters off Baja 
California, north along the western coasts of the continental U.S., 
British Columbia, and Southeast Alaska, west through the Gulf of Alaska 
and Aleutian Islands, and in the Bering Sea north to Cape Newenham and 
the Pribilof Islands (Caretta et al., 2014). Within U.S. west coast 
waters, five stocks of harbor seals are recognized: (1) Southern Puget 
Sound (south of the Tacoma Narrows Bridge); (2) Washington Northern 
Inland Waters (including Puget Sound north of the Tacoma Narrows 
Bridge, the San Juan Islands, and the Strait of Juan de Fuca); (3) Hood 
Canal; (4) Oregon/Washington Coast; and (5) California. Seals belonging 
to the Oregon/Washington Coast stock are included in this analysis.
    Harbor seals generally are non-migratory, with local movements 
associated with tides, weather, season, food availability, and 
reproduction (Scheffer and Slipp 1944; Fisher 1952; Bigg 1969, 1981). 
Harbor seals do not make extensive pelagic migrations, though some long 
distance movement of tagged animals in Alaska (900 km) and along the 
U.S. west coast (up to 550 km) have been recorded (Brown and Mate 1983, 
Herder 1986, Womble 2012). Harbor seals have also displayed strong 
fidelity to haulout sites (Pitcher and Calkins 1979, Pitcher and 
McAllister 1981).
    The harbor seal is the most widespread and abundant resident 
pinniped in Oregon. They haul out to rest at low tide on sand bars in 
most bays and estuaries along the Oregon coast. They are also found on 
nearshore rocks and islands usually within 3 miles of the coast. Within 
Coos Bay, four harbor seal haulout sites have been identified by ODFW 
(Wright 2013); three of which have documented pup sightings. From the 
inlet to the upper Bay, these are South Slough (southeast of the 
entrance channel), Pigeon Point, Clam Island, and Coos Port. However, 
only three of the four haulouts are in the project area including the 
South Slough, Pigeon Point, and Clam Island (see Figure 4-1 of the 
application). Harbor seals generally foraging with in close proximity 
to their haulouts. For example, a study of radio tagged harbor seals in 
San Francisco Bay found that the majority of foraging trips were less 
than 10 km from their regular haulout (Grigg et al., 2012), and a 
similar study in Humboldt Bay found that the majority of seals 
travelled 13 km or less to forage (Ougzin 2013). Both studies found 
that harbors seals typically forage at in relatively shallow water 
depths; a median value of 7 m was reported for the San Francisco Bay 
Study (Grigg et al., 2012).
    The most recent haulout counts were conducted by ODFW in May and 
June 2014. In 2014, 333 seals were observed at Coos Bay haulouts in 
June (Wright, pers comm., August 27, 2019). May yielded slightly higher 
numbers, as expected since it is closer to peak pupping season; 
however, the South Slough haulout site was not surveyed in May due to 
fog.
    Marine mammal presence and abundance data collection throughout 
Coos Bay in 2017 and 2018. These surveys were vessel based line 
transect surveys. Observations made by AECOM during May 2017 site-
specific surveys found similar patterns to the ODFW aerial surveys. 
More than 350 observations of harbor seals were recorded in the estuary 
over the four days of survey. AECOM conducted additional surveys during 
November and December 2018 using vessel based line transect surveys and 
aerial surveys using a drone to establish a fall/winter local abundance 
estimate for harbor seals. A maximum of 167 seals were hauled out 
between the Clam Island and Pigeon Point haulouts at any one time. ODFW 
indicates it is likely many harbor seals are year-round residents in 
Coos Bay and relay on these waters for all life stages and behaviors 
including, by not limited to, breeding, pupping, and foraging (Wright 
2013).

[[Page 56788]]

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.

                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
                                                 Generalized  hearing
                Hearing group                           range*
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales)  7 Hz to 35 kHz.
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 phocid 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 four pinniped (three 
otariid and one phocid) species) have the reasonable potential to co-
occur with the proposed survey activities. Please refer to Table 2. Of 
the cetacean species that may be present, one is classified as a low-
frequency cetacean (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.

Description of Sound and the Sources Used

    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

[[Page 56789]]

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 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 
hertz (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 decibels (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 section). 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

[[Page 56790]]

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.
    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 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 
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; Tal et al., 2015). 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--NMFS defines a noise-induced threshold shift (TS) 
as ``a change, usually an increase, in the threshold of audibility at a 
specified frequency or portion of an individual's hearing range above a 
previously established reference level'' (NMFS, 2016). The amount of 
threshold shift is customarily expressed in dB (ANSI 1995, Yost 2007). 
A TS can be permanent (PTS) or temporary (TTS). As described in NMFS 
(2016), there are numerous factors to consider when examining the 
consequence of TS, including, but not limited to, the signal temporal 
pattern (e.g., impulsive or non-impulsive), likelihood an individual 
would be exposed for a long enough duration or to a high enough level 
to induce a TS, the magnitude of the TS, time to recovery (seconds to 
minutes or hours to days), the frequency range of the exposure (i.e., 
spectral content), the hearing and vocalization frequency range of the 
exposed species relative to the signal's frequency spectrum (i.e., how 
animal uses sound within the frequency band of the signal; e.g., 
Kastelein et al., 2014), and the overlap between the animal and the 
source (e.g., spatial, temporal, and spectral). When analyzing the 
auditory effects of noise exposure, it is often helpful to broadly 
categorize sound as either impulsive--noise with high peak sound 
pressure, short duration, fast rise-time, and broad frequency content--
or non-impulsive. When considering auditory effects, vibratory pile 
driving is considered a non-impulsive source while impact pile driving 
is treated as an impulsive source.
    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). NMFS defines PTS as a permanent, irreversible increase in 
the threshold of audibility at a specified frequency or portion of an 
individual's hearing range above a previously established reference 
level (NMFS 2018). Available data from humans and other terrestrial 
mammals indicate that a 40 dB threshold shift approximates PTS onset 
(see NMFS 2018 for review). 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).
    NMFS defines TTS as a temporary, reversible increase in the 
threshold of audibility at a specified frequency or portion of an 
individual's hearing range above a previously established reference 
level (NMFS 2018). Based on data from cetacean TTS measurements (see 
Finneran 2014 for a review), a TTS of 6 dB is considered the minimum 
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et 
al., 2000; Finneran et al., 2000; Finneran et al., 2002).
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
masking, below). For example, a marine mammal may be able to readily 
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal 
is traveling through the open ocean, where ambient noise is lower and 
there are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts. We note that reduced hearing sensitivity as 
a simple function of aging has been observed in marine mammals, as well 
as humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several decibels above (a 40-dB threshold shift approximates PTS onset; 
e.g., Kryter et al., 1966; Miller 1974) that inducing mild TTS (a 6-dB 
threshold shift approximates TTS onset; e.g., Southall

[[Page 56791]]

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 of cetaceans and pinnipeds. 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 (2016).
    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 with the sound source (e.g., whether it is 
moving or stationary, number of sources, distance from the source). 
Please see Gomez et al., 2016 for a review of studies involving marine 
mammal behavioral responses to sound.
    The acoustic habitat in Coos Bay is regularly elevated by medium to 
large-sized boats. Site-specific ambient noise data were collected 
during a baseline survey by AECOM in Coos Bay in May 2017 and November 
and December 2018. Underwater sound levels for water transit vessels, 
which operate throughout the day in Coos Bay, ranged from 152 dB to 177 
dB. The results suggested that the ambient noise level was 
approximately 120 dB, with high daily variability due to vessel 
traffic. We expect some level of habituation and or sensitization, 
described in more detail below, to occur due to the existing acoustic 
environment in Coos Bay.
    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,

[[Page 56792]]

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; Gailey et al., 2016).
    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, temporary exertion and displacement from the area where the 
signal provokes flight to, in extreme cases, marine mammal strandings 
(Evans and England, 2001). However, it should be noted that response to 
a perceived predator does not necessarily invoke flight (Ford and 
Reeves, 2008), and whether individuals are solitary or in groups may 
influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress Responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous

[[Page 56793]]

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).
    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 anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore, 2014). Masking can be tested 
directly in captive species (e.g., Erbe, 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).
    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.
    Potential Effects of USACE's Activity--As described previously (see 
Description of Active Acoustic Sound Sources section), USACE proposes 
to conduct vibratory pile driving in Coos Bay. 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. It 
is likely that the onset of 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 onset of behavioral disturbance from anthropogenic sound 
depends on both external factors (characteristics of sound sources and 
their paths) and the specific characteristics of the receiving animals 
(hearing, motivation, experience, demography) and is difficult to 
predict (Southall et al., 2007).
    Sounds produced by vibratory driving or removal 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 would expect any masking to occur concurrently within the 
zones of

[[Page 56794]]

behavioral harassment already estimated for vibratory pile driving and 
removal, and which have already been taken into account in the exposure 
analysis.
    The biological significance of behavioral disturbance is difficult 
to predict, especially if the detected disturbances appear minor. 
While, generally speaking, 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 impacts on health or fitness, such as drastic 
changes in diving/surfacing patterns or significant habitat abandonment 
are extremely unlikely to result from this activity.

Anticipated Effects on Marine Mammal Habitat

    The proposed activities would not result in permanent impacts to 
habitats used directly by marine mammals, but 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 in this preamble. The most likely impact to marine 
mammal habitat occurs from pile driving effects on likely marine mammal 
prey (i.e., fish) near the MOF. Impacts to the immediate substrate 
during installation and removal of piles are anticipated, but these 
would be limited to minor, 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 
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.
    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 pile driving or removal 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 these IHAs, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determinations.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Take of marine mammals incidental to USACE's pile driving and 
removal activities could occur by Level B harassment only, as pile 
driving has the potential to result in disruption of behavioral 
patterns for individual marine mammals. Based on the nature of the 
activity, Level A harassment is neither anticipated nor proposed to be 
authorized. The proposed mitigation

[[Page 56795]]

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 
estimates for each IHA.

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).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source (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., impact pile 
driving seismic airguns) or intermittent (e.g., scientific sonar) 
sources. The USACE's proposed activities include the use of continuous, 
non-impulsive (vibratory pile driving) therefore, the 120 dB re 1 
[mu]Pa (rms) is applicable.
    Level A Harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise. The 
technical guidance identifies the received levels, or thresholds, above 
which individual marine mammals are predicted to experience changes in 
their hearing sensitivity for all underwater anthropogenic sound 
sources, and reflects the best available science on the potential for 
noise to affect auditory sensitivity by:
    [ssquf] Dividing sound sources into two groups (i.e., impulsive and 
non- impulsive) based on their potential to affect hearing sensitivity;
    [ssquf] Choosing metrics that best address the impacts of noise on 
hearing sensitivity, i.e., sound pressure level (peak SPL) and sound 
exposure level (SEL) (also accounts for duration of exposure); and
    [ssquf] Dividing marine mammals into hearing groups and developing 
auditory weighting functions based on the science supporting that not 
all marine mammals hear and use sound in the same manner.
    These thresholds were developed by compiling and synthesizing the 
best available science, and are provided in Table 4 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-technicalguidance.

                     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[mu]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

[[Page 56796]]

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 source level 
measurements available for certain pile types and sizes from the 
similar environments recorded from underwater pile driving projects 
(CALTRANS 2015, WSDOT 2010) that were used to determine reasonable 
sound source levels likely result from the USACE's pile driving and 
removal activities (Table 5).

Table 5--Predicted Sound Source Levels for Both Installation and Removal
                                of Piles
------------------------------------------------------------------------
                                                                Sound
                                                                source
                         Pile type                             level at
                                                              10 meters
------------------------------------------------------------------------
12-inch steel H-pile 1.....................................    150 dBRMS
24-inch AZ steel sheet 1...................................    160 dBRMS
30-inch steel pipe pile 2..................................    164 dBRMS
------------------------------------------------------------------------
\1\ Average typical sound pressure levels referenced from Caltrans
  (2015) and were either measured or standardized to 10 m from the pile.
\2\ Average sound pressure levels measured at the Vashon Ferry Terminal
  (WSDOT, 2010).

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 from 
vibratory 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 incur PTS. Inputs used in the 
User Spreadsheet (Table 6), and the resulting isopleths are reported 
below (Table 7).

  Table 6--NMFS Technical Guidance (2018) User Spreadsheet Input To Calculate PTS Isopleths for Vibratory Pile
                                                     Driving
        [User spreadsheet input--Vibratory Pile Driving Spreadsheet Tab A.1 Vibratory Pile Driving Used]
----------------------------------------------------------------------------------------------------------------
                                                    12-in H piles       24-in sheet piles        30-in piles
                                                  (install/removal)     (install/removal)     (install/remove)
----------------------------------------------------------------------------------------------------------------
Source Level (RMS SPL)........................                   150                   160                   164
Weighting Factor Adjustment (kHz).............                   2.5                   2.5                   2.5
Number of piles within 24-hr period...........                    25                    25                     6
Duration to drive a single pile (min).........                    10                    10                    60
Propagation (xLogR)...........................                    15                    15                    15
Distance of source level measurement (meters).                    10                    10                    10
----------------------------------------------------------------------------------------------------------------


                     Table 7--NMFS Technical Guidance (2018) User Spreadsheet Outputs to Calculate Level A Harassment PTS Isopleths.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                         User spreadsheet output                                                      PTS isopleths (meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                         Levl A harassment
                                                                         -------------------------------------------------------------------------------
                 Activity                    Sound source level at 10 m                                        High-
                                                                          Low- frequency  Mid- frequency     frequency        Phocid          Otariid
                                                                             cetaceans       cetaceans       cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Vibratory Pile Driving/Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
12-in H pile steel installation/removal...  150 dB SPL..................             3.3             0.3             4.8             2.0             0.1

[[Page 56797]]

 
24-in sheet pile installation/removal.....  160 dB SPL..................            15.2             1.3            22.4             9.2             0.6
30-in pile installation/removal...........  164 dB SPL..................            35.7             3.2            52.8            21.7             1.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

Level B Harassment
    Utilizing the practical spreading loss model, USACE determined 
underwater noise will fall below the behavioral effects threshold of 
120 dB rms for marine mammals at the distances shown in Table 8 for 
vibratory pile driving/removal. Table 8 below provides all Level B 
harassment radial distances (m) and their corresponding areas (km\2\) 
during the USACE's proposed activities. It is undetermined whether 
sheet piles, H-piles, or a combination of the two will be used for MOF 
construction; therefore, the USACE estimated potential take based on 
the larger disturbance zone for Level B harassment (i.e., for sheet 
pile--9.1 km\2\) for the 12-inch H pile Level B harassment zone.

   Table 8--Radial Distances (meters) to Relevant Behavioral Isopleths and Associated Ensonified Areas (square
                              kilometers (km2)) Using the Practical Spreading Model
----------------------------------------------------------------------------------------------------------------
                                                                          Level B
                Activity                    Received level at 10 m      harassment      Level B harassment zone
                                                                         zone (m)*               (km2)
----------------------------------------------------------------------------------------------------------------
                                         Vibratory Pile Driving/Removal
----------------------------------------------------------------------------------------------------------------
12-inch H piles installation/removal....  150 dB SPL................           1,000  9.1 (actual calculated
                                                                                       zone is 2).
24-inch sheet pile installation/removal.  160 dB SPL................           4,642  9.1
30-inch pile installation/removal.......  164 dB SPL................           8,577  11.5
----------------------------------------------------------------------------------------------------------------

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 vibratory pile driving/removal for 
each acoustic threshold were estimated using group size estimates and 
local observational data to create a density estimate. As previously 
stated, take by Level B harassment only will be considered for this 
action. Distances to Level A harassment thresholds are relatively small 
and mitigation is expected to avoid Level A harassment from these 
activities.

Harbor Seals

    Over the last several decades, intermittent and independent surveys 
of harbor seal haul outs in Coos Bay have been conducted. The most 
recent aerial survey of haulouts occurred in 2014 by ODFW. Those 
surveys were conducted during a time when the highest number of animals 
would be expected to haul out (i.e., the latter portion of the pupping 
season (May and June) and at low tide). In 2014, 333 seals were 
observed at Coos Bay haulouts in June (Wright, pers comm., August 27, 
2019).
    AECOM conducted surveys vessel-based surveys in May/June 2017 and 
November 2018 from the Highway 101 Bridge to the seaward entrance to 
the Coos Bay estuary. In 2017, during the line transect surveys, there 
were an estimated 374 harbor seals counted in 19 groups with a relative 
density of 6.2 harbor seals/km. In 2018, because of the low number of 
harbor seals sightings during the line transect effort, reliable 
statistical estimates of species density could not be accurately 
calculated. However, for comparison with the May 2017 data, the number 
of seals observed/km yielded a sighting rate of 0.12 harbor seals/km.
    AECOM also conducted three days of aerial (drone) flyovers at the 
Clam Island and Pigeon Point haulouts to capture aerial imagery during 
November and December 2018 to determine a fall/winter estimate for 
harbor seals. This aerial field effort observed a maximum of 167 harbor 
seals hauled out at Clam Island and 41 harbor seals hauled out at 
Pigeon Point on any one day. Based on these counts, an estimate of 
relative density was determined for the study area and ranged from 8.5-
11.1 harbor seals/km\2\. Because the pile driving and removal for the 
MOF will likely occur over the winter season and to be conservative, 
USACE used the maximum density of 11.1 harbor seals/km\2\ to calculate 
take.
    The estimated take for each IHA was calculated using this density 
multiplied by the area ensonified above the threshold (9.1 km\2\ for 
sheet piles and 11.5 km\2\ for 30-in piles) multiplied by the number of 
days per activity (e.g., 7 days of vibratory pile driving per pile type 
for a total of 14 days of pile driving activity each year). Therefore, 
a total of 1,601 instances of take by Level B harassment are proposed 
for harbor seals in both Year 1 for installation and in Year 2 for 
removal (Table 9). Because the Level A harassment zones are relatively 
small (21.7 m at the largest for pile driving/removal of 30-in piles), 
and activities will occur over a small number of days, we believe the 
Protected Species Observer (PSO) will be able to effectively monitor 
the Level A harassment zones and we do not anticipate take by Level A 
harassment of harbor seals.

[[Page 56798]]

California Sea Lions and Steller Sea Lions

    No data are available to calculate density estimates California sea 
lion and Steller sea lions; therefore, USACE considers likely 
occurrences in estimating take for California sea lions and Steller sea 
lions. As described in the Description of Marine Mammals section, no 
haulouts for California sea lions and Steller sea lions exist within 
Coos Bay where harassment from exposure to pile driving could occur, 
however, these species do haul out on the beaches adjacent to the 
entrance to Coos Bay. These animals forage individually and seasonal 
use of Coos Bay have been observed, primarily in the spring and summer 
when prey are present. The estimate for daily California sea lion and 
Steller sea lions abundance (n = 1) was based on recent marine mammal 
surveys in Coos Bay (AECOM 2017).
    For this reason, USACE estimates one California and Steller sea 
lion may be present each day of pile driving. We multiplied 1 animal by 
the number of days per activity (e.g., 7 days of vibratory pile driving 
per pile type). Therefore, a total of 14 instances of take by Level B 
harassment are proposed for both California sea lions and Steller sea 
lions in both Year 1 for installation and in Year 2 for removal (Table 
9). Because the Level A harassment zones are relatively small (Less 
than 2 m at the largest for pile driving/removal of 30-in piles), and 
activities will occur over a small number of days, we believe the PSO 
will be able to effectively monitor the Level A harassment zones and we 
do not anticipate take by Level A harassment of California sea lions or 
Steller sea lions.

Northern Elephant Seals

    The abundance estimate for Northern elephant seals was based on the 
maximum number of seals observed at Cape Arago, a prominent haulout 
site roughly 6 km south of Coos Bay jetties. Surveys were conducted 
between 2002 and 2005 (Scordino 2006) and the reference abundance (n = 
54) was the maximum count observed. USACE applied a 3.8 percent annual 
population growth rate (NMFS 2014c) to approximate the relative 
abundance of elephant seals in 2019 (i.e., n = 91). Lastly, an 
estimated density of elephant seals was calculated across the project 
area extended to include Cape Arago (i.e., approximately 30 km\2\) as a 
basis for determining the number of animals that could be present in 
Level B harassment zones during vibratory pile driving activities. This 
calculated density is 3.03 Northern elephant seals/km\2\. The estimated 
take was calculated using this density (3.03 animals/km\2\) multiplied 
by the area ensonified above the threshold (9.1 km\2\ for sheet piles 
and 11.5 km\2\ for 30-in piles) multiplied by the number of days per 
activity (e.g., 7 days of vibratory pile driving per pile type). 
Therefore, a total of 437 instances of take by Level B harassment are 
proposed for Northern elephant seals in both Year 1 for installation 
and in Year 2 for removal (Table 9). Because the Level A harassment 
zones are relatively small (21.7-m isopleth at the largest for pile 
driving/removal of 30-in piles), and activities will occur over a small 
number of days, we believe the PSO will be able to effectively monitor 
the Level A harassment zones and we do not anticipate take by Level A 
harassment of Northern elephant seals.

Killer Whales

    It is not possible to calculate density for killer whales in Coos 
Bay as they are not present in great abundance; therefore, USACE 
estimates take based on likely occurrence and considers group size. 
During migration, the species typically travels singly or as a mother 
and calf pair. This species has been reported in Coos Bay only a few 
times in the last decade. The typical group size for transient killer 
whales is two to four, consisting of a mother and her offspring (Orca 
Network 2018). Males and young females also may form small groups of 
around three for hunting purposes (Orca Network 2018). Previous 
sightings in Coos Bay documented a group of five transient killer 
whales in May 2007 (as reported by the Seattle Times) and a pair of 
killer whales were observed during the 2017 May surveys. USACE assumes 
that a group of two killer whales come into Coos Bay and could enter a 
Level B harassment zone for one day in each year of pile driving 
activities. Therefore, a total of two instances of take by Level B 
harassment are proposed for killer whales in both Year 1 for 
installation and in Year 2 for removal (Table 9). Because the Level A 
harassment zones are relatively small (Less than a 4-m isopleth at the 
largest for pile driving/removal of 30-in piles), and activities will 
occur over a small number of days, we believe the PSO will be able to 
effectively monitor the Level A harassment zones and we do not 
anticipate take by Level A harassment of killer whales.

Harbor Porpoise

    It is not possible to calculate density for harbor porpoise in Coos 
Bay as they are not present in great abundance; therefore, USACE 
estimates take based on likely occurrence and considers group size. 
Harbor porpoise are most often seen singly, in pairs, or in groups of 
up to 10, although there are reports of aggregations of up to 200 
harbor porpoises. No harbor porpoises were detected during recent 
marine mammal surveys within the Coos Bay estuary (AECOM 2017, 2018). 
However, harbor porpoises were counted during aerial surveys of marine 
mammals off the coasts of California, Oregon, and Washington. The 
maximum estimated count of harbor porpoises within approximately 1,700 
km\2\ of Coos Bay (n = 24 in January 2011) was the basis for estimated 
abundance (Adams et al., 2014). USACE applied a 4 percent annual 
population growth rate (NMFS 2013a) to approximate the relative 
abundance of harbor porpoises in 2019 (i.e., n = 33). Lastly, an 
estimated density of harbor porpoise was calculated across 
approximately 1,700 km\2\ as a basis for determining the number of 
animals that could be present in Level B harassment zones during 
vibratory pile driving activities. This calculated density is 0.019 
harbor porpoise/km\2\. The estimated take was calculated using this 
density (0.019 animals/km\2\) multiplied by the area ensonified above 
the threshold (9.1 km\2\ for sheet piles and 11.5 km\2\ for 30-in 
piles) multiplied by the number of days per activity (e.g., 7 days of 
vibratory pile driving per pile type, 14 total days). Therefore, a 
total of four instances of take by Level B harassment are proposed for 
harbor porpoise in both Year 1 for installation and in Year 2 for 
removal (Table 9). Because the Level A harassment zones are relatively 
small (a 52.8-m isopleth at the largest for pile driving/removal of 30-
in piles), and activities will occur over a small number of days, we 
believe the PSO will be able to effectively monitor the Level A 
harassment zones and we do not anticipate take by Level A harassment of 
harbor porpoise.

Gray Whales

    It is not possible to calculate density for gray whales in Coos Bay 
as they are not present in great abundance; therefore, USACE estimates 
take based on likely occurrence and considers group size. Gray whales 
are frequently observed traveling alone or in small, unstable groups, 
although large aggregations may be seen in feeding and breeding 
grounds. The maximum estimated count of gray whales within 
approximately 1,700 km\2\ of Coos Bay (n = 10) was the basis for 
estimated abundance (Adams et al., 2014). USACE then applied a 6 
percent population growth rate (NOAA 2014b) to derive the

[[Page 56799]]

current estimated abundance to approximate the relative abundance of 
gray whales in 2019 (i.e., n = 16). Lastly, an estimated density of 
gray whales was calculated across approximately 1,700 km\2\ as a basis 
for determining the number of animals that could be present in Level B 
harassment zones during vibratory pile driving activities. This 
calculated density is 0.0094 gray whales/km\2\. The estimated take was 
calculated using this density (0.0094 animals/km\2\) multiplied by the 
area ensonified above the threshold (9.1 km\2\ for sheet piles and 11.5 
km\2\ for 30-in piles) multiplied by the number of days per activity 
(e.g., 7 days of vibratory pile driving per pile type, 14 total days). 
Therefore, a total of two instances of take by Level B harassment are 
proposed for gray whales in both Year 1 for installation and in Year 2 
for removal (Table 9). Because the Level A harassment zones are 
relatively small (a 35.7-m isopleth at the largest for pile driving/
removal of 30-in piles), and activities will occur over a small number 
of days, we believe the PSO will be able to effectively monitor the 
Level A harassment zones and we do not anticipate take by Level A 
harassment of gray whales.
    For both year 1 and year 2, Table 9 below summarizes the proposed 
estimated take for all the species described above as a percentage of 
stock abundance.

                              Table 9--Proposed Estimated Take by Level B Harassment and as a Percentage of Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Level B           Level B          Level B         Level B      Total take by Level B   Total take by Level B
                                       harassment  AZ    harassment  30-  harassment  AZ  harassment 30-  harassment (percent by   harassment  (percent
                                        sheets (or H-      inch  piles     sheets (or H-    inch  piles           stock)                 by stock)
            Marine mammal                  plies)      ------------------     plies)     ---------------------------------------------------------------
                                     ------------------                  ----------------
                                            YR-1              YR-1         YR-2 removal    YR-2 removal      YR-1 installation         YR-2 removal
----------------------------------------installation------installation----------------------------------------------------------------------------------
Harbor seal (Phoca vitulinai).......               707               894             707             894  1,601 (2.3 percent)...  1,601 (2.3 percent).
Northern Elephant seal (Mirounga                   193               244             193             244  437 (0.2 percent).....  437 (0.2 percent).
 angustirostris).
Steller sea lion (Eumetopias                         7                 7               7               7  14 (0.02 percent).....  14 (0.02 percent).
 jubatus).
California sea lion (Zalophus                        7                 7               7               7  14 (less than 0.001     14 (less than 0.001
 californianus).                                                                                           percent).               percent).
Gray whale (Eschrichtius robustus)..                 1                 1               1               1  2.....................  2
                                                                                                          (less than 0.001        (less than 0.001
                                                                                                           percent).               percent).
Killer whale (Orcinus orca).........                   2
                                                       2                          2 (0.5          2 (0.5
                                                                                percent)       percent).
                                     --------------------------------------------------------------------
Harbor porpoise (Phocoena phocoena).                 2                 2               2               2  4 (0.008 percent).....  4 (0.008 percent).
--------------------------------------------------------------------------------------------------------------------------------------------------------

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 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.
    The following mitigation measures are included in the proposed 
IHAs:

Timing Restrictions

    All work will be conducted during daylight hours. If poor 
environmental conditions restrict visibility full visibility of the 
shutdown zone, pile installation would be delayed.

Shutdown Zone for In-Water Heavy Machinery Work

    For in-water heavy machinery work other than pile driving, if a 
marine mammal comes within 10 m of such operations, operations shall 
cease and vessels shall reduce speed to the minimum level required to 
maintain steerage and safe working conditions.

Shutdown Zones

    For all pile driving/removal activities, the USACE will establish 
shutdown zones for a marine mammal species that is greater than its 
corresponding Level A harassment zone. To be conservative, the USACE is 
proposing to implement one cetacean shutdown zone (55 m) and one 
pinniped shutdown zone (25 m) during any pile driving/removal activity 
(i.e., during sheet piles, H-piles, and 30-in steel pile installation 
and removal) (Table 10) which exceeds the maximum calculated PTS 
isopleths as described in Table 7. The purpose of a shutdown zone is 
generally to define an area within which shutdown of the activity would 
occur upon sighting of a marine mammal (or in anticipation of an animal 
entering the defined area).

[[Page 56800]]



                                             Table 10--Pile Driving Shutdown Zones During Project Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               Shutdown zones  (radial distance in m, area in km\2*\)
                                                          ----------------------------------------------------------------------------------------------
                         Activity                            Low-frequency      Mid-frequency      High-frequency
                                                               cetaceans          cetaceans          cetaceans            Phocid            Otariid
--------------------------------------------------------------------------------------------------------------------------------------------------------
In-Water Construction Activities:
Heavy machinery work (other than pile driving)...........       10 (0.00015)       10 (0.00015)       10 (0.00015)       10 (0.00015)       10 (0.00015)
Vibratory Pile Driving/Removal:
    12-in H pile steel installation/removal..............       55 (0.00475)       55 (0.00475)       55 (0.00475)       25 (0.00098)       25 (0.00098)
    24-in sheet pile installation/removal................       55 (0.00475)       55 (0.00475)       55 (0.00475)       25 (0.00098)       25 (0.00098)
    30-in pile installation/removal......................       55 (0.00475)       55 (0.00475)       55 (0.00475)       25 (0.00098)       25 (0.00098)
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Note: km\2\ were divided by two to account for land.

Non-Authorized Take Prohibited

    If a species enters or approaches the Level B harassment zone and 
that species is either not authorized for take or its authorized takes 
are met, pile driving and removal activities must shut down immediately 
using delay and shutdown procedures. Activities must not resume until 
the animal has been confirmed to have left the area or an observation 
time period of 15 minutes has elapsed for pinnipeds and small cetaceans 
and 30 minutes for large whales.
    Based on our evaluation of the USACE's proposed measures, 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:
    [ssquf] Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
    [ssquf] 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);
    [ssquf] Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
    [ssquf] How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
    [ssquf] Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
    [ssquf] Mitigation and monitoring effectiveness.

Pre-Activity Monitoring

    Prior to the start of daily in-water construction activity, or 
whenever a break in pile driving of 30 min or longer occurs, PSOs will 
observe the shutdown and monitoring zones for a period of 30 min. The 
shutdown zone will be cleared when a marine mammal has not been 
observed within the zone for that 30-min period. If a marine mammal is 
observed within the shutdown zone, pile driving activities will not 
begin until the animal has left the shutdown zone or has not been 
observed for 15 min. If the Level B Harassment Monitoring Zone has been 
observed for 30 min and no marine mammals (for which take has not been 
authorized) are present within the zone, work can continue even if 
visibility becomes impaired within the Monitoring Zone. When a marine 
mammal permitted for Level B harassment take has been permitted is 
present in the Monitoring zone, piling activities may begin and Level B 
harassment take will be recorded.

Monitoring Zones

    The USACE will establish and observe monitoring zones for Level B 
harassment as presented in Table 8. The monitoring zones for this 
project are areas where SPLs are equal to or exceed 120 dB rms (for 
vibratory pile driving/removal). These zones provide utility for 
monitoring conducted for mitigation purposes (i.e., shutdown zone 
monitoring) by establishing monitoring protocols for areas adjacent to 
the shutdown zones. Monitoring of the Level B harassment zones enables 
observers to be aware of and communicate the presence of marine mammals 
in the project area, and thus prepare for potential shutdowns of 
activity. The USACE will also be gathering information to help better 
understand the impacts of their proposed activities on species and 
their behavioral responses.

Visual Monitoring

    Monitoring would be conducted 30 minutes before, during, and 30 
minutes after all pile driving/removal activities. In addition, PSO 
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/removed. Pile driving/
removal activities include the time to install, 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.

[[Page 56801]]

    Monitoring will be conducted by PSOs from on land and boat. The 
number of PSOs will vary from one to three, depending on the type of 
pile driving, method of pile driving and size of pile, all of which 
determines the size of the harassment zones. Monitoring locations will 
be selected to provide an unobstructed view of all water within the 
shutdown zone and as much of the Level B harassment zone as possible 
for pile driving activities. During vibratory driving or removal of AZ-
sheets or H-piles, two PSOs will be present. One PSO will be located on 
the shoreline adjacent to the MOF site or on the barge used for driving 
piles. The other PSO will be boat-based and detect animals in the 
water, along with monitoring the three haulout sites in the Level B 
harassment zone (i.e., Pigeon Point, Clam Island/North Spit, and South 
Slough). During vibratory driving and removal of steel pipe piles (30-
in), three PSOs will be present. As indicated above, one PSO will be on 
the shoreline or barge adjacent to the MOF site. A second PSO will be 
stationed near the South Slough haul out site, and the third PSO will 
be boat-based and make observations while actively monitoring at and 
between the two remaining haulout sites (i.e., Pigeon Point and Clam 
Island).
    In addition, PSOs will work in shifts lasting no longer than 4 
hours with at least a 1-hour break between shifts, and will not perform 
duties as a PSO for more than 12 hours in a 24[hyphen]hour period (to 
reduce PSO fatigue).
    Monitoring of pile driving shall be conducted by qualified, NMFS-
approved PSOs, who shall have no other assigned tasks during monitoring 
periods. The USACE shall adhere to the following conditions when 
selecting PSOs:
    [ssquf] Independent PSOs shall be used (i.e., not construction 
personnel);
    [ssquf] At least one PSO must have prior experience working as a 
marine mammal observer during construction activities;
    [ssquf] Other PSOs may substitute education (degree in biological 
science or related field) or training for experience;
    [ssquf] Where a team of three or more PSOs are required, a lead 
observer or monitoring coordinator shall be designated. The lead 
observer must have prior experience working as a marine mammal observer 
during construction; and
    [ssquf] The USACE shall submit PSO CVs for approval by NMFS for all 
observers prior to monitoring. The USACE shall ensure that the PSOs 
have the following additional qualifications:
    [ssquf] 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;
    [ssquf] Experience and ability to conduct field observations and 
collect data according to assigned protocols;
    [ssquf] Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
    [ssquf] Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    [ssquf] Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior;
    [ssquf] 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; and
    [ssquf] Sufficient training, orientation, or experience with the 
construction operations to provide for personal safety during 
observations.

Reporting of Injured or Dead Marine Mammals

    In the unanticipated event that the planned activity clearly causes 
the take of a marine mammal in a manner prohibited by the IHA, such as 
serious injury, or mortality, the USACE must immediately cease the 
specified activities and report the incident to the NMFS Office of 
Protected Resources and the West Coast Region Stranding Coordinator. 
The report must include the following information:
    [ssquf] Time and date of the incident;
    [ssquf] Description of the incident;
    [ssquf] Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    [ssquf] Description of all marine mammal observations and active 
sound source use in the 24 hours preceding the incident;
    [ssquf] Species identification or description of the animal(s) 
involved;
    [ssquf] Fate of the animal(s); and
    [ssquf] Photographs or video footage of the animal(s).
    Activities must not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS will work with USACE to 
determine what measures are necessary to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. The USACE may not 
resume their activities until notified by NMFS.
    In the event the USACE discovers an injured or dead marine mammal, 
and the lead observer 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), the USACE must immediately report the 
incident to the Office of Protected Resources, NMFS, and the West Coast 
Region Stranding Coordinator, NMFS. The report must include the same 
information as the bullets described above. Activities may continue 
while NMFS reviews the circumstances of the incident. NMFS will work 
with the USACE to determine whether additional mitigation measures or 
modifications to the activities are appropriate.
    In the event that the USACE discovers an injured or dead marine 
mammal, and the lead observer determines that the injury or death is 
not associated with or related to the specified activities (e.g., 
previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), the USACE must report the incident 
to the Office of Protected Resources, NMFS, and the West Coast Region 
Stranding Coordinator, NMFS, within 24 hours of the discovery.

Final Report

    The USACE shall submit a draft report to NMFS no later than 90 days 
following the end of construction activities or 60 days prior to the 
issuance of any subsequent IHA for the project. The USACE shall provide 
a final report within 30 days following resolution of NMFS' comments on 
the draft report. Reports shall contain, at minimum, the following:
    [ssquf] Date and time that monitored activity begins and ends for 
each day conducted (monitoring period);
    [ssquf] Construction activities occurring during each daily 
observation period, including how many and what type of piles driven;
    [ssquf] Deviation from initial proposal in pile numbers, pile 
types, average driving times, etc.;
    [ssquf] Weather parameters in each monitoring period (e.g., wind 
speed, percent cloud cover, visibility);
    [ssquf] Water conditions in each monitoring period (e.g., sea 
state, tide state);
    [ssquf] For each marine mammal sighting:
    [cir] Species, numbers, and, if possible, sex and age class of 
marine mammals;

[[Page 56802]]

    [cir] Number of individuals of each species (differentiated by 
month as appropriate) detected within the monitoring zones, and 
estimates of number of marine mammals taken, by species (a correction 
factor may be applied to total take numbers, as appropriate);
    [cir] Description of any observable marine mammal behavior 
patterns, including bearing and direction of travel and distance from 
pile driving activity;
    [cir] Type of construction activity that was taking place at the 
time of sighting;
    [cir] Location and distance from pile driving activities to marine 
mammals and distance from the marine mammals to the observation point;
    [cir] If shutdown was implemented, behavioral reactions noted and 
if they occurred before or after shutdown.
    [ssquf] Description of implementation of mitigation measures within 
each monitoring period (e.g., shutdown or delay);
    [ssquf] Other human activity in the area within each monitoring 
period;
    [ssquf] A summary of the following:
    [cir] Total number of individuals of each species detected within 
the Level B Harassment Zone, and estimated as taken if correction 
factor appropriate;
    [cir] Total number of individuals of each species detected within 
the Level A Harassment Zone and the average amount of time that they 
remained in that zone; and
    [cir] Daily average number of individuals of each species 
(differentiated by month as appropriate) detected within the Level B 
Harassment Zone, and estimated as taken, if appropriate.

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, the majority of our analyses applies to all 
the species listed in Table 9, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. For harbor seals, because there is 
thought to be a potential resident population and potential repeat 
takes of individuals, we provide a supplemental analysis independent of 
the other species for which we propose to authorize take. Also, because 
both the number and nature of the estimated takes anticipated to occur 
are identical in years 1 and 2, the analysis below applies to each of 
the IHAs.
    The USACE did not request, and NMFS is not proposing to authorize, 
take in the form of injury, serious injury, or mortality. The nature of 
the work precludes the likelihood of serious injury or mortality, and 
the mitigation is expected to ensure that no Level A harassment occurs. 
For all species and stocks, any take would occur within a limited, 
confined area of any given stock's home range (Coos Bay). Take would be 
limited to Level B harassment only. Exposure to noise resulting in 
Level B harassment for all species is expected to be temporary and 
minor due to the general lack of use of Coos Bay by cetaceans and 
pinnipeds, as explained above. In general, cetacean and non-harbor seal 
pinnipeds are infrequent visitors with only occasional sightings within 
Coos Bay. Cetaceans such as transient killer whales may wander into 
Coos Bay; however, any behavioral harassment occurring during the 
project is highly unlikely to impact the health or fitness of any 
individuals, much less effect annual rates of recruitment or survival, 
given any exposure would be very brief with any harassment potential 
from the project decreasing to zero once the animals leave the bay. 
There are no habitat areas of particular importance for cetaceans 
(e.g., biologically important area, critical habitat, primary foraging 
or calving habitat) within Coos Bay. Further, the amount of take 
proposed to be authorized for any given stock is very small when 
compared to stock abundance, demonstrating that a very small percentage 
of the stock would be affected at all by the specified activity. 
Finally, while pile driving could occur year-round, pile driving would 
be intermittent (not occurring every day) and primarily limited to the 
MOF site, a very small portion of Coos Bay.
    For harbor seals, the impact of harassment on the stock as a whole 
is negligible given the stocks very large size (70,151 seals). However, 
we are aware that it is likely a resident population of harbor seals 
resides year round within Coos Bay. While this has not been 
scientifically investigated through research strategies such as 
tagging/mark-recapture techniques, anecdotal evidence suggests some 
seals call Coos Bay home year-round, as suggested through AECOM's 
winter surveys. The exact home range of this potential resident 
population is unknown but harbor seals, in general, tend to have 
limited home range sizes. Therefore, we can presume that some harbor 
seals will be repeatedly taken. Repeated, sequential exposure to pile 
driving noise over a longer duration could result in more severe 
impacts to individuals that could affect a population; however, the 
limited number of non-consecutive pile driving days for this project 
means that these types of impacts are not anticipated. Further, these 
animals are already exposed, and likely somewhat habituated, to 
industrial noises such as USACE maintenance dredging, commercial 
shipping and fishing vessel traffic (Coos Bay contains a major port), 
and coastal development.
    In summary, although this potential small resident population is 
likely to be taken repeatedly, the impacts of that take are negligible 
to the stock because the number of repeated days of exposure is small 
(14 or fewer) and non-consecutive, the affected individuals represent a 
very small subset of the stock that is already exposed to regular 
higher levels of anthropogenic stressors, injurious noise levels are 
not proposed for authorization, and the pile driving/removal would not 
take place during the pupping season and during a time in which harbor 
seal density is greatest.
    The following factors primarily support our preliminary 
determination that the impacts resulting from each of these two years 
of activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:

[[Page 56803]]

    [ssquf] No serious injury or mortality is anticipated or 
authorized;
    [ssquf] No Level A harassment is anticipated or authorized;
    [ssquf] The number and intensity of anticipated takes by Level B 
harassment is relatively low for all stocks;
    [ssquf] No biologically important areas have been identified for 
the effected species within Coos Bay;
    [ssquf] For all species, including the Oregon/Washington Coastal 
stock of harbor seals, Coos Bay is a very small part of their range; 
and
    [ssquf] No pile driving would occur during the harbor seal pupping 
season; therefore, no impacts to pups from this activity is likely to 
occur.
    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 each of the two years of 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.
    The take of seven marine mammal stocks proposed for authorization 
comprises no more than 2.3 percent of any stock abundance.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, for each proposed IHA, 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, for both 
proposed IHAs, 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)

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally, in this case with the West Coast Region 
Protected Resources Division, whenever we propose to authorize take for 
endangered or threatened species.
    No incidental take of ESA-listed marine mammal 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 Authorizations

    As a result of these preliminary determinations, NMFS proposes to 
issue two IHAs to USACE for pile driving and removal activities 
associated with the North Jetty maintenance and repairs project in Coos 
Bay, Oregon over the course of two non-consecutive years, beginning 
September 2020 through June 2023, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. 
Drafts of the proposed IHAs can be found at https://www.fisheries.noaa.gov/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 IHAs for the proposed pile 
driving and removal activities associated with the USACE's North Jetty 
maintenance and repairs project in Coos Bay, Oregon. We also request at 
this time comment on the potential renewal of these proposed IHAs as 
described in the paragraph below. Please include with your comments any 
supporting data or literature citations to help inform decisions on the 
request for these IHAs or a subsequent Renewal.
    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 second IHA 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.
     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: October 17, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2019-23081 Filed 10-22-19; 8:45 am]
 BILLING CODE 3510-22-P