[Federal Register Volume 86, Number 157 (Wednesday, August 18, 2021)]
[Notices]
[Pages 46199-46226]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-17725]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB163]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Palmer Station Pier Replacement 
Project, Antarctica

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

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

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SUMMARY: NMFS has received a request from the National Science 
Foundation (NSF) for authorization to take marine mammals incidental to 
the Palmer Station Pier Replacement Project in Anvers Island, 
Antarctica. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS 
is requesting comments on its proposal to issue an incidental 
harassment authorization (IHA) to incidentally take marine mammals 
during the specified activities. NMFS is also requesting comments on a 
possible one-time, one-year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorizations and agency responses will be 
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than 
September 17, 2021.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Written comments should be submitted 
via email to <a href="/cdn-cgi/l/email-protection#d1988581ff81b0a4bdb8bfb491bfbeb0b0ffb6bea7"><span class="__cf_email__" data-cfemail="fcb5a8acd2ac9d8990959299bc92939d9dd29b938a">[email protected]</span></a>.
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at 
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: Robert Pauline, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

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

[[Page 46200]]

    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment.
    Accordingly, NMFS plans to adopt NSF's Initial Environmental 
Evaluation (IEE), which is generally the equivalent of an environmental 
assessment (EA) under the Antarctic Conservation Act (16 U.S.C. 2401 et 
seq.), provided our independent evaluation of the document finds that 
it includes adequate information analyzing the effects on the human 
environment of issuing the IHA.
    We will review all comments submitted in response to this notice 
and the draft IEE prior to concluding our NEPA process or making a 
final decision on the IHA request.

Summary of Request

    On December 29, 2020, NMFS received a request from the National 
Science Foundation (NSF) for an IHA to take marine mammals incidental 
to construction activities associated with the Palmer Station Pier 
Replacement Project on Anvers Island, Antarctica. NSF submitted several 
revisions of the application until it was deemed adequate and complete 
on July 15, 2021. NSF's request is for take of a small number of 17 
species of marine mammals by Level B harassment and/or Level A 
harassment. Neither NSF nor NMFS expects serious injury or mortality to 
result from this activity and, therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    The purpose of the project is to construct a replacement pier at 
Palmer Station on Anvers Island, Antarctica for the United States 
Antarctic Program. It is severely deteriorated, and needs to be 
replaced as soon as possible. Construction of the replacement pier and 
removal of the existing pier will require down-the-hole (DTH) pile 
installation, and vibratory pile removal. Limited impact driving will 
occur only to proof piles after they have been installed. The proposed 
project is expected to take up to 89 days of in-water work and will 
include the installation of 52 piles and removal of 36 piles. 
Construction is expected to begin no later than November 2021, 
depending on local sea ice conditions, and would be completed by mid-
April 2022. The pile driving and removal activities can result in take 
of marine mammals from sound in the water which results in behavioral 
harassment or auditory injury. Note that hereafter (unless otherwise 
specified) the term ``pile driving'' is used to refer to both pile 
installation (including DTH pile installation) and pile removal.

Dates and Duration

    The work described here is likely to begin in October or November 
2021 and would be completed by mid-April 2022 with demobilization 
occurring no later than June of 2022. The construction season is 
limited due to ice and weather. Construction work cannot begin until 
the sea ice has vacated Hero Inlet and work must be completed prior to 
the return of sea ice so that personnel and equipment can be safely 
demobilized. The proposed IHA would be effective for a period of one 
year from October 1, 2021 through September 30, 2022. In-water 
activities will occur during daylight hours only. Work would be 
conducted 7 days per week for 12 hours (hr) per day and up to 89 days 
of in-water construction is anticipated.

Specific Geographic Region

    The activities would occur at Palmer Station on Hero Inlet, between 
Gamage Point and Bonaparte Point on the southwestern coast of Anvers 
Island in the Antarctica Peninsula (Figure 1). The coordinates for the 
station are: 64[deg]46' S, 64[deg]03' W. Substrate at the project 
location consists of solid rock. In addition to the pier, there are 
several buildings, plus two large fuel tanks, and a helicopter pad. The 
area frequently experiences high winds, up to 130 kilometers (km) per 
hour, or greater. Palmer Station lies outside the Antarctic Circle, so 
there are 19 hours of light and 5 hours of twilight at the height of 
austral summer and only 5 hours of daylight each day in the middle of 
austral winter. Hero Inlet is a narrow inlet (approximately 135 meters 
(m) wide) along the southwest side of Anvers Island. Maximum observed 
tidal range is 2.5 m with mean sea level at 0.72 m. The shoreline and 
upland area is generally rocky or exposed bedrock. Ice cliffs rise 
above the station.
BILLING CODE 3510-22-P

[[Page 46201]]

[GRAPHIC] [TIFF OMITTED] TN18AU21.168

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    The existing pier at Palmer Station consists of a sheetpile 
bulkhead backfilled with gravel and cobble that was built in 1967. It 
is severely deteriorated, and needs to be replaced as soon as possible.
    This project would replace the existing pier with a new steel pipe 
pile supported concrete deck pier, new modern energy absorbing fender 
system and on-site power and lighting. Work on the fendering system 
would be above water. In-water work with the potential to produce 
underwater noise includes demolition of the existing pier, construction 
of the new pier and installation of wave attenuator piles. While piles 
for the wave attenuator will be installed in this project, the wave 
attenuator itself would be installed later. (NMFS does not expect 
installation of the wave attenuator to result in take.)
    The existing bulkhead pier must be demolished prior to construction 
of the new pier. The existing sheetpile cofferdam bulkhead would be 
demolished and the sheets would be removed by a vibratory hammer or cut 
off at the mudline. Sheet pile removed from the pier cell would be 
loaded onto the material barge for disposal. A pier cell is a structure 
that has hollow sections (i.e., cells).
    New pile installation would include steel gravel-filled pipe piles 
as outlined in Table 1. The deck and pile caps for the pier are 
supported by the piles, which are installed in holes (sockets) created 
in the shallow bedrock by the DTH systems. Support vessels, including a 
tugboat, one stationary barge, a temporary floating construction 
platform, a 16-ft. (5-m) skiff and one 200 horsepower work boat would 
be used for the duration of the project to complete in-water work. A 
separate gravel barge would deliver material at the beginning of the 
project, but would only be onsite for approximately 3 days.

[[Page 46202]]



                                              Table 1--Pile Summary
----------------------------------------------------------------------------------------------------------------
                                                                           Socket
               Structure                     Size and type of pile      depth (feet        Number of piles
                                                                           [ft])
----------------------------------------------------------------------------------------------------------------
Pier Abutment.........................  32 or 36-in. diameter steel              30  4.
                                         pile in approximate 38-in.
                                         diameter holes.
Pier..................................  36-in. steel pile in                     20  Up to 18.\a\
                                         approximate 38-in. diameter
                                         holes.
Retaining Wall........................  H pile inserted in 24-in.                10  Up to 9.\a\
                                         diameter hole.
Wave Attenuator Piles.................  24-in. steel pile.............           20  2.
Rigid Hull Inflatable Boat Fender.....  24-in. steel pile.............           20  3.
Template Piles (temporary)............  24-in. steel pile.............           10  32.\b\
Sheetpile Removal.....................  3/8-in........................            0  20.
----------------------------------------------------------------------------------------------------------------
\a\ Includes 2 piles as a contingency for design flexibility.
\b\ 16 of these piles are removed once they are no longer needed as templates.

    The primary source of underwater noise that may result in takes 
during construction would be from the installation and removal of piles 
to support the pier and fenders. Table 2 shows project components and 
activities that could result in the take of marine mammals.

      Table 2--Project Components: Potential for Marine Mammal Take
------------------------------------------------------------------------
                                                          Potential for
       Project component               Equipment          marine mammal
                                                          take (yes/no)
------------------------------------------------------------------------
Pile/Sheetpile Removal........  Excavator and loader    No.
                                 operated above water.
                                Crane operated above    No.
                                 water.
                                Vibratory hammer......  Yes.
                                Underwater cutting      Yes.
                                 tool \1\.
Pile Installation.............  Crane operated above    No.
                                 water.
                                DTH drill.............  Yes.
                                Impact hammer.........  Yes.
                                Vibratory hammer......  Yes.
Anode Protection..............  Pneumatic hydrogrinder  Yes.
                                 or needle scaler \2\.
Rock chipping (optional)......  Hoe ram...............  Yes.\3\
------------------------------------------------------------------------
\1\ Underwater cutting tool operation, if necessary, would occur on the
  same days as vibratory extraction. Estimated take associated with
  cutting tool operation was calculated by utilizing higher underwater
  source levels associated with vibratory extraction.
\2\ These tools scrape off surfaces for rust, paint, etc. Use of these
  tools would be limited and would occur once pile installation is
  complete. Underwater source levels are estimated at 146 dB at 10m and
  have been accounted for in the take estimate.
\3\ Rock chipping may not be necessary. However if it does occur it
  would occur on the same days as DTH pile installation.

    Piles would be socketed in place since the substrate comprises 
rocky or exposed bedrock. This involves drilling and hammering into the 
rock to create a socket hole deeper and larger than the pile diameter. 
The primary technique for creating the socket holes and their piles 
would be by DTH pile installation. DTH installation uses both rotary 
and hammering actions on a drill bit (i.e., like a hammer drill hand 
tool) to create a hole in the bedrock or sediment. It uses the rotation 
of the drill system and a (typically pneumatic) hammering mechanism to 
break up rock to create a hole. Since construction techniques could 
vary depending on specific site conditions, a small impact hammer may 
also need to be used at the end of the process to firmly seat the pile 
in the hole. This may require no more than 10 strikes. It is unlikely 
that a vibratory hammer would be used to install piles. Once the pile 
is set, the remaining void space is filled with a high-performance 
cement-based sealing grout. Temporary template piles used during 
construction would be removed with a vibratory hammer or cut off at the 
mudline.
    Approximately one to two piles would be installed over a 12-hour 
work day. As a precautionary measure, it is assumed that two 
installation activities would be occurring at the same time (i.e., 
simultaneous). The main method of pile installation would be by DTH. 
Two DTH systems would be available on site and could be used 
simultaneously. One vibratory hammer would possibly be used to remove 
existing piles, and one impact hammer could be used to proof piles.
    Rock chipping may be required to ensure accurate pile location and 
alignment with the sea bottom at pile locations. Rock chipping involves 
the use of excavators fitted with hydraulic ``breakers'' or powerful 
percussion hammers used to break up large concrete structures. If rock 
chipping is necessary, it would likely occur prior to but on the same 
days as DTH pile installation.
    The project design includes installation of anode corrosion 
protection for the major submerged steel components. Divers would 
install aluminum alloy anodes below the waterline by welding and using 
a pneumatic hydrogrinder, needle scaler, or similar equipment. They 
would use these tools to scrape rust, paint, etc. off surfaces. This 
activity would occur only after pile installation is complete. The 
hydrogrinder or needle scaler would only be used approximately one hour 
per day over an 18-day period.
    Table 3 provides the number of piles and the estimated number of 
days of installation.

[[Page 46203]]



             Table 3--Pile Installation and Removal Duration
------------------------------------------------------------------------
                                                          Total days of
          Pile type                 Number of piles        installation
                                                               \1\
------------------------------------------------------------------------
36-in. piles \2\ (pier Bents   Up to 18................               47
 2, 3, and 4).
32-in. piles (pier abutment    4.......................
 Bent 1).
24-in. RHIB (rigid hull        3.......................               16
 inflatable boat) fender.
24-in. template piles........  16......................
24-in. retaining wall........  2.......................
24-in. H piles (retaining      Up to 9.................
 wall).
Pile Removal (24-in.)........  16......................                4
Sheetpile Removal............  20......................                4
Anode Installation...........  0.......................               18
Rock chipping................  0.......................
                               Up to 88................               89
------------------------------------------------------------------------
\1\ This is a conservative estimate. It is possible that 24-in. piles
  may be driven on the same day as 36-in. piles. If this occurs, overall
  days may be reduced for pile installation.
\2\ For the purposes of calculating take, there is reference to Scenario
  1A which involves pile installation of two 36-in piles simultaneously.
  In this table, Scenarios 1 and 1A are synonymous in terms of
  representing the number of estimated days for installation.

Description of Marine Mammals in the Area of Specified Activities

    Table 4 lists all species or stocks for which take is expected and 
proposed to be authorized for this action, and summarizes best 
available information on the population or stock, including regulatory 
status under the MMPA and Endangered Species Act. For taxonomy, we 
follow Committee on Taxonomy (2020). Marine mammals in the Project Area 
do not constitute stocks under U.S. jurisdiction; therefore, there are 
no stock assessment reports. Additional information on these species 
may be found in Section 3 of NSF's application.
    For species occurring in United States Antarctic Marine Living 
Resources (AMLR) survey area of the Southern Ocean, the International 
Union for the Conservation of Nature (IUCN) status is provided. The 
IUCN systematically assesses the relative risk of extinction for 
terrestrial and aquatic plant and animal species via a classification 
scheme using five designations, including three threatened categories 
(Critically Endangered, Endangered, and Vulnerable) and two non-
threatened categories (Near Threatened and Least Concern) 
(www.iucnredlist.org/; accessed June 10, 2021). These assessments are 
generally made relative to the species' global status, and therefore 
may have limited applicability when marine mammal stocks are defined 
because we analyze the potential population-level effects of the 
specified activity to the relevant stock. However, where stocks are not 
defined, IUCN status can provide a useful reference.

                 Table 4--Marine Mammals Potentially Present in the Vicinity of the Project Area
----------------------------------------------------------------------------------------------------------------
                                                                           ESA/MMPA/IUCN status   Abundance (CV)
         Common name            Scientific name          Stock \2\                  \3\                \4\
----------------------------------------------------------------------------------------------------------------
                      Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
----------------------------------------------------------------------------------------------------------------
Family Balaenidae (right
 whales):
    Southern right whale.....  Eubalaena         ........................  E/D/LC                1,755
                                australis.                                                        (0.62).\5\
Family Balaenopteridae
 (rorquals):
    Humpback whale...........  Megaptera         ........................  E/D/LC                9,484
                                novaeangliae                                                      (0.28).\5\
                                australis.
    Antarctic minke whale....  Balaenoptera      ........................  -/NT                  18,125
                                bonaerensis.                                                      (0.28).\5\
    Fin whale................  B. physalus       ........................  E/D/VU                4,672
                                quoyi.                                                            (0.42).\5\
    Blue whale...............  B. musculus       ........................  E/D/EN                1,700.\13\
                                musculus.
    Sei whale................  Balaenoptera      ........................  E/D/EN                626.\14\
                                borealis.
----------------------------------------------------------------------------------------------------------------
                        Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
----------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale..............  Physeter          ........................  E/D/VU                12,069
                                macrocephalus.                                                    (0.17).\7\
Family Ziphiidae (beaked
 whales):
    Arnoux's beaked whale....  Berardius         ........................  /DD                   Unknown.
                                arnuxii.
    Southern bottlenose whale  Hyperoodon        ........................  -/LC                  53,743
                                planifrons.                                                       (0.12).\8\
Family Delphinidae:
    Hourglass dolphin........  Lagenorhynchus    ........................  -/LC                  144,300
                                cruciger.                                                         (0.17).\9\
    Killer whale.............  Orcinus orca \1\  ........................  -/DD                  24,790
                                                                                                  (0.23).\8\
    Long-finned pilot whale..  Globicephala      ........................  -/LC                  200,000
                                melas edwardii.                                                   (0.35).\9\
----------------------------------------------------------------------------------------------------------------
                                     Order Carnivora--Superfamily Pinnipedia
----------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals
 and sea lions):
    Antarctic fur seal.......  Arctocephalus     South Georgia...........  -/LC                  2,700,000.\10\
                                gazella.
Family Phocidae (earless
 seals):
    Southern elephant seal...  Mirounga leonina  South Georgia...........  -/LC                  401,572.\11\
    Weddell seal.............  Leptonychotes     ........................  -/LC                  500,000-1,000,0
                                weddellii.                                                        00.\12\
    Crabeater seal...........  Lobodon           ........................  -/LC                  5,000,000-10,00
                                carcinophaga.                                                     0,000.\12\
    Leopard seal.............  Hydrurga          ........................  -/LC                  222,000-440,000
                                leptonyx.                                                         .\12\
----------------------------------------------------------------------------------------------------------------
\1\ Three distinct forms of killer whale have been described from Antarctic waters; referred to as types A, B,
  and C, they are purported prey specialists on Antarctic minke whales, seals, and fish, respectively (Pitman
  and Ensor, 2003; Pitman et al., 2010).
\2\ For most species in the AMLR, stocks are not delineated and entries refer generally to individuals of the
  species occurring in the research area.

[[Page 46204]]

 
\3\ 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. Any species
  listed under the ESA is automatically designated under the MMPA as depleted. IUCN status: Endangered (EN),
  Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD).
\4\ CV is coefficient of variation. All abundance estimates, except for those from Reilly et al., (2004) (right,
  humpback, minke, and fin whales), are for entire Southern Ocean (i.e., waters south of 60[deg]S) and not the
  smaller area comprising the Southwest Fisheries Science Center (SWFSC) research area.
\5\ Abundance estimates reported in Reilly et al., (2004) for the Commission for the Conservation of Antarctic
  Marine Living Resources (CCAMLR) survey area from 2000. Surveys include Antarctic Peninsula (473,300 km\2\)
  and Scotia Sea (1,109,800 km\2\) strata, which correspond roughly to SWFSC's Antarctic Research Area (ARA), as
  reported by Hewitt et al., (2004).
\6\ Southern Ocean abundance estimate (Branch et al., 2007).
\7\ Southern Ocean abundance estimate (IWC, 2001 in Whitehead, 2002).
\8\ Southern Ocean abundance estimate from circumpolar surveys covering 68 percent of waters south of 60[deg]S
  from 1991-98 (Branch and Butterworth, 2001).
\9\ Southern Ocean abundance estimate derived from surveys conducted from 1976-88 (Kasamatsu and Joyce, 1995).
\10\ South Georgia abundance estimate; likely >95 percent of range-wide abundance (Forcada and Staniland, 2009).
  Genetic evidence shows two distinct population regions, likely descended from surviving post-sealing
  populations at South Georgia, Bouvet[oslash]ya, and Kerguelen Islands (Wynen et al., 2000; Forcada and
  Staniland, 2009). Individuals from the South Georgia population (including breeding populations at the South
  Orkney and South Shetland Islands, which are within the ARA) are likely to occur in the ARA.
\11\ Four genetically distinct populations are recognized: the Peninsula Vald[eacute]s population in Argentina,
  the South Georgia population in the South Atlantic Ocean, the Kerguelen population in the South Indian Ocean
  and the Macquarie population in the South Pacific Ocean (Slade et al., 1998; Hoelzel et al., 2001). Animals
  occurring in ARA are likely to belong to South Georgia population, which includes subpopulations at South
  Georgia Island (>99 percent of population) and at the South Orkney and South Shetland Islands; South Georgia
  population abundance estimate from 2001 (McMahon et al., 2005).
\12\ Range-wide abundance estimates (Thomas and Terhune, 2009; Bengtson, 2009; Rogers, 2009).
\13\ Southern Ocean abundance estimate (Branch et al., 2007). CI is confidence interval.
\14\ South of 60[deg]S.

Antarctic Minke Whale

    Antarctic minke whales are similar in shape and coloration to the 
more global species of minke whale (B. acutorostrata). The two species 
differ in relative size and shape of several cranial features, and 
Antarctic minke whales lack the distinct white flipper mark of the more 
common minke whale.
    The seasonal distribution and migration patterns of nearly all 
populations of minke whales are poorly understood (Risch et al., 2019). 
Antarctic minke whales are abundant from 60[deg]S to the ice edge 
during the austral summer then retreat in the austral winter to 
breeding grounds in mid-latitudes in the Pacific and other locations 
off Australia and South Africa. Antarctic minke feed mainly on 
euphausiids (krill (Euphausia superba)). This species is highly 
associated with sea ice and is generally less abundant in ice-free 
waters. In general, minke whales are commonly observed alone or in 
small groups of two or three individuals. Aggregations of up to 400 may 
form on occasion in high latitudes. During the feeding season, mature 
females are found closer to the ice than immature females, and immature 
males are more solitary than mature males.
    Over the period January 21, 2019 through March 31, 2020, one minke 
whale was observed during bird observation studies at Palmer Station in 
Arthur Harbor, which is on the other side of the peninsula separated 
from Hero Inlet. The whale was observed feeding about 300 m offshore. A 
lead Principal Investigator studying marine mammals as part of the 
Long-Term Ecological Research Program at Palmer Station notes minke 
whales are common within a few miles of the station (Ari Friedlander, 
personal communication).

Fin Whale

    Fin whales are closely related to blue and sei whales. Northern and 
southern populations remain separated leading to genetic isolation of 
the populations. The fin whale is found in most large water masses of 
the world, from tropical to polar regions. However, in the most extreme 
latitudes individuals may be absent near the ice limit. Overall, fin 
whale densities in the southern hemisphere tend to be higher outside 
the continental slope than inside it.
    Fin whales feed on an assortment of prey items, depending on their 
availability (Kawamura 1980; as cited in Wursig et al., 2018); their 
diet varies with season and locality. Southern Hemisphere fin whales 
have a diet of almost exclusively krill, and other planktonic 
crustaceans. In the Southern Hemisphere, fin whales seasonally migrate 
north to south; they feed in the summer at high latitudes and breed and 
fast in the winter at low latitudes.
    One fin whale was recently seen within a few miles of the station 
(Ari Friedlander, personal communication).

Blue Whale

    Blue whales in the Southern Hemisphere are on average larger than 
those in the Northern Hemisphere. Blue whales are a cosmopolitan 
species with North Atlantic, North Pacific, and Southern hemisphere 
populations. They were historically most abundant in the Southern 
Ocean, but are very rare today in the Project Area. Due to food 
availability they are found predominantly offshore. Blue whales feed 
almost exclusively on euphausiids in areas of cold water upwelling.

Sei Whale

    Sei whales inhabit all ocean basins; they are oceanic and not 
commonly found in shelf seas. Sei whales migrate seasonally, spending 
the summer months feeding in the subpolar higher latitudes and 
returning to the lower latitudes to calve in winter. In the Southern 
Hemisphere, they are rarely found as far south as blue, fin, and minke 
whales, with summer concentrations mainly between the subtropical and 
Antarctic convergences (between 40[deg]S and 50[deg]S). Sei feed on 
copepods, euphausiids, shoals of fish, and squid if they are 
encountered.

Hourglass Dolphin

    Hourglass dolphins are pelagic and circumpolar in the Southern 
Ocean; they are found in Antarctic and sub-Antarctic waters. Most 
sightings of live hourglass dolphins reflect observer effort, and are 
centered on the Antarctic convergence with most sightings from the 
Drake Passage. Hourglass dolphins often feed in large aggregations of 
seabirds such as great shearwaters and black-browed albatrosses, and in 
plankton slicks (White et al., 1999; as cited in Wursig et al., 2018). 
Their prey items include small fish (about 2.4 g and a length of 55 
mm), small squid, and crustaceans. They are believed to feed in surface 
waters.
    Migratory movements of this species are not well known. It is 
thought that hourglass dolphins from the Antarctic convergence zone and 
the continental shelf break may move into sub-Antarctic waters in 
winter. Thus, the range of the species thus probably shifts north and 
south with the seasons (Carwardine 1995; as cited in Wursig et al., 
2018). Although oceanic, hourglass dolphins are often observed near 
islands and banks, in areas with turbulent waters; they have been 
observed in the Project Area (Ari Friedlander, personal communication).

Humpback Whale

    Humpback whales are distributed throughout the world. They are 
highly migratory, spending spring through fall on feeding grounds in 
mid- or high-latitude waters, and wintering on calving grounds in the 
tropics, where they do not eat (Dawbin 1966; as referenced in Wursig et 
al., 2018). Seven populations of humpback whales are

[[Page 46205]]

found in the Southern hemisphere and feed throughout the waters off 
Antarctica. In the Southern Hemisphere, humpback whales feed in 
circumpolar waters and migrate to breeding grounds in tropical waters 
to the north. Seven breeding populations are recognized by the 
International Whaling Commission in the Southern Hemisphere, and these 
are linked to six feeding areas in the Antarctic. Bettridge et al., 
(2015) identify the southeast Pacific breeding stock as feeding in 
waters to the west of the Antarctic Peninsula where Palmer station is 
located. These animals breed in the Pacific-Central America waters.
    Humpback whales are considered generalists, feeding on euphausiids 
and various species of small schooling fish. They appear to be unique 
among large whales in their use of bubbles to corral or trap these 
schooling fish.
    Humpback whales are the most common whale seen within a few miles 
of the station (Ari Friedlander, personal communication). From January 
21, 2019 through March 31, 2020, marine mammal sightings have been 
recorded during bird observation studies at Palmer Station. On January 
23, 2019, three humpback whales (two adults and one juvenile) were 
observed feeding off Torgersen Island, and one adult and one juvenile 
were observed feeding in Arthur Harbor on January 26, 2019. Several 
groups of up to four individuals (likely adults and juveniles) were 
observed feeding in Arthur Harbor in early February 2019. No humpbacks 
were observed after February 12. At the end of May 2019, two humpback 
whales were again observed near Bonaparte Point, with no other 
sightings until the end of December 2019 when one humpback was observed 
feeding in Arthur Harbor. In late December 2019 through early February 
2020, individual whales or groups of two adults and possibly a juvenile 
feeding in Arthur Harbor were recorded on 10 separate occasions. A 
large group of five whales (four adults and a juvenile) was observed in 
Arthur Harbor on March 3, 2020. This was the last sighting recorded.

Killer Whale

    The killer whale is found in all the world's oceans and most seas. 
It is the largest member of the family Delphinidae and has very 
distinctive black-and-white coloration. Antarctic killer whales make 
periodic rapid long-distance migrations to subtropical waters, possibly 
for skin maintenance (Durban and Pitman 2011; as referenced in Wursig 
et al., 2018). Killer whales are social animals that are usually 
observed traveling in groups containing a few to 20 or more 
individuals. Reports of larger groups usually involve temporary 
aggregations of smaller, more stable social units.
    Currently only one species of killer whale is recognized (O. orca), 
but it is likely that some of genetically distinct forms found in 
different regions of the world represent distinct species (Wursig et 
al., 2018). In the Antarctic, five distinct forms of killer whale have 
been identified: Types A, B1, B2, C, and D. They differ in coloration, 
morphology, and in some cases diet (Pitman and Ensor 2003). Types B1 
and B2 are the most common form observed around the Antarctic Peninsula 
and Anvers Island (Durban et al., 2016).
    Killer whales prey on a wide range of vertebrates and 
invertebrates; they have no natural predators other than humans. It is 
the only cetacean that routinely preys upon marine mammals, with 
attacks or kills documented for 50 different species. Mammalian taxa 
that are prey of killer whales include other cetaceans--both mysticetes 
and odontocetes--pinnipeds, sirenians, mustelids and, on rare 
occasions, ungulates. A variety of fish species are also important food 
of killer whales. In the Antarctic, killer whales in open water prey on 
Antarctic minke whales, seals, and fish.
    Killer whales are commonly observed within a few miles of the 
station (Ari Friedlander, personal communication).

Long-Finned Pilot Whale

    Long-finned pilot whales inhabit the cold temperate waters of both 
the North Atlantic and the Southern Ocean. They are circumpolar in the 
Southern Hemisphere and occur as far north as 14[deg]S in the Pacific 
and south to the Antarctic Convergence (Olson 2009). Pilot whales are 
found in both nearshore and pelagic environments. Pilot whales are 
generally nomadic, but are highly social and are usually observed in 
schools of several to hundreds of animals. They also have been observed 
in mixed species aggregations. Their diet consists mostly of squid and 
other cephalopods, with smaller amounts of fish. Pilot whales are known 
to dive deep for prey; the maximum dive depth measured is about 1,000 
m.

Arnoux's Beaked Whale

    Arnoux's beaked whales inhabit vast areas of the Southern 
Hemisphere, between 24[deg]S and Antarctica. They are a deep diving 
species and can be found in areas of heavy ice cover. Little is known 
of the diet of Arnoux's beaked whales but one individual's stomach was 
found to be mostly filled with squid beaks (Wursig et al. 2018). 
Arnoux's beaked whales often occur in groups of 6-10 and occasionally 
up to 50 or more (Balcomb 1989). Arnoux's beaked whales have been 
observed in the Project area. Because they are heavily ice-associated 
Arnoux's, beaked whales may be directly affected by loss of sea ice due 
to climate change.

Southern Bottlenose Whale

    Southern bottlenose whales are widely distributed throughout the 
Southern Hemisphere, mainly south of 30[deg]S, and are most common 
between 58[deg]S and 62[deg]S. Bottlenose whales seem to prefer deeper 
waters and, like other beaked whales, they make regular deep dives to 
forage. Stomach content analyses of six southern bottlenose whales show 
that this species feeds primarily on squid (MacLeod et al., 2003). 
Bottlenose whales are typically observed in small groups of up to 10 
individuals, though groups of up to 20 animals of mixed age/sex classes 
have been reported. Social behaviors have not been studied in southern 
bottlenose whales.

Southern Right Whale

    Southern right whales are found between 20[deg]S and 60[deg]S. 
Right whales are ``skimmers'' (Baumgartner et al., 2007; as cited in 
Wursig et al., 2018). They feed offshore in pelagic regions in areas of 
high productivity by swimming forward with the mouth agape. Feeding can 
occur at or just below the surface, where it can be observed easily, or 
at depth. At times, right whales apparently feed very close to the 
bottom, because they are observed to surface at the end of an extended 
dive with mud on their heads. Typical feeding dives last for 10-20 min. 
It is likely that krill comprise a high proportion of the diet in 
southern right whales.

Sperm Whale

    Sperm whales are widely distributed, but distribution of the sexes 
are different. Female sperm whales almost always inhabit water deeper 
than 1,000 m and at latitudes less than 40[deg]S, corresponding roughly 
to sea surface temperatures greater than 15[deg]C. Sperm whales dive to 
about 600 m below the surface where they hunt primarily for squid. 
Distribution and relative abundance can vary in response to prey 
availability, most notably squid (Jaquet & Gendron 2002).
    Large males from high latitudes can be found in almost any ice-free 
deep water. Therefore, any sperm whales encountered in Antarctic waters 
are highly likely to be male. They are more likely to be sighted in 
productive waters, such as those along the edges of

[[Page 46206]]

continental shelves. Sperm whales have low birth rates, slow growth and 
high survival rates.

Antarctic Fur Seal

    Antarctic fur seals have a circumpolar distribution. They are found 
from the Antarctic continent to the Falkland Islands. Land-based 
breeding strongly influences the distribution of females and their 
foraging ecology. Lactating females are restricted to foraging in the 
waters immediately surrounding the breeding beaches, whereas males can 
disperse after mating. Female distribution expands after breeding as 
they leave rookeries.
    Antarctic krill dominates the diet of Antarctic fur seals in the 
vicinity of the Project Area. Penguins are occasionally taken by 
Antarctic fur seal bulls. Killer whales are likely the main predator of 
the species, but leopard seals are thought to limit the population 
growth at Elephant Island in the South Shetland Islands. Large bulls of 
other species also prey on pups where species coexist.
    Over three seasons from 2019 through 2020 (i.e., two Antarctic 
summers and one winter), marine mammal sightings have been recorded 
during daily bird observation studies at Palmer Station. A total of 73 
fur seals were observed either hauled out or swimming in Hero Inlet 
during the Antarctic summer months between January and March 2019. Over 
a longer summer period between October 2019 and March 2020, there were 
242 seals observed in Hero Inlet, with the majority of seals hauled out 
(see Table 6-1 in application). During the winter months between March 
and October 2019, 70 seals were observed in Hero Inlet. Fewer fur seals 
were observed over the same 2019-2020 months in Arthur Harbor. See 
Section 6 of the application for additional details on seal 
observations in the project vicinity (NSF, personal communication).

Crabeater Seal

    Crabeater seals have a circumpolar Antarctic distribution; they 
spend the entire year in pack ice. They move over large distances with 
the annual advance and retreat of pack ice. Although they can be found 
anywhere within the pack ice zone, they are typically found at the edge 
of the continental shelf, as well as in the marginal ice zone (Burns et 
al., 2004 and Southwell et al., 2005; as referenced in Wursig et al., 
2018). Crabeater seals sometimes congregate in large groups of up to 
several hundred, which might be associated with general patterns of 
seasonal movement or foraging. As with other Antarctic seals, crabeater 
seals have a daily haul out pattern in summer that generally involves 
hauling out on ice floes during the middle of the day (Bengtson and 
Cameron, 2004; as referenced in Wursig et al., 2018), though usually 
less than 80 percent are hauled out on the ice at the same time.
    Antarctic krill is the primary prey item for crabeater seals, 
constituting over 95 percent of their diet. They also eat small 
quantities of fish and squid ([Oslash]ritsland, 1977; as referenced in 
Wursig et al., 2018). Crabeater seals do not appear to seasonally 
switch prey. During daily nocturnal foraging periods in summer, 
crabeater seals will nearly continuously dive for up to 16 h at a time.
    Over three seasons (i.e., two Antarctic summers and one winter) 
from January 21, 2019 through March 31, 2020, marine mammal sightings 
have been recorded during bird observation studies at Palmer Station. 
Crabeater seals were commonly observed individually or in small groups 
lying on the ice in Arthur Harbor and Hero Inlet in late January and 
February of 2019; the frequency of sightings decreased by March. Groups 
of up to four individuals were observed in or near the Project Area in 
early April of 2019, some were lying on the floating dock. Groups of 
crabeater seals were observed swimming in Hero Inlet near Gamage Point 
in April and early May of 2019. No crabeater seals were recorded in 
June, but in early July of 2019 groups of two seals and individuals 
were observed on the ice at Arthur Harbor and Hero Inlet, and on the 
shore at Bonaparte Point. No crabeater seals were observed from mid-
July to mid-October of 2019. Observations of crabeater seals increased 
in Arthur Harbor frequency into November of 2019, with sightings 
continuing into December. However, from January of 2020 through March 
of 2020, crabeater seals were only observed on nine occasions; this was 
less frequent than sightings recorded from January to March of 2019 
(NSF, personal communication).

Southern Elephant Seal

    Southern elephant seals are the largest of all pinnipeds. Southern 
elephant seals can be divided into three distinct stocks: Maguire 
Island, Iles Kerguelen, and South Georgia, the latter of which is 
relevant to the Project Area. There is some separation of feeding areas 
between the sexes, with males tending to feed more in continental shelf 
waters, while females either use ice-free waters broadly associated 
with the Antarctic Polar Front, or the marginal ice zone, moving 
northward as the ice expands. Elephant seals prey on deepwater and 
bottom dwelling organisms, including fish, squid, crab, and octopus. 
They are extraordinary divers with some dive depths exceeding 1,500 m 
and lasting up to 120 minutes.
    Over three seasons (two Antarctic summers and one winter) from 
January 21, 2019 through March 31, 2020, one elephant seal was observed 
lying on shore near Palmer Station in early March of 2019. No other 
seals were observed again until October of 2019 when on six days over 
the period October 8 to 19, 2019 a single seal was observed lying on 
the ice in Arthur Harbor. Additional sightings were noted in November 
and December 2019 in Hero Inlet. Sightings increased from January 6 to 
February 10, 2020, when elephant seals were observed at Bonaparte Point 
as individuals or in groups as large as 7 nearly every day and 
sometimes several times a day. No elephant seals were observed after 
February 10, 2020. This is noticeably different than 2019, when no 
elephant seals were observed in January or February (NSF, personal 
communication).

Leopard Seal

    The leopard seal (Hydrurga leptonyx) is the largest Antarctic pack 
ice seal. Leopard seals are solitary pinnipeds, and are widely 
dispersed at low densities on the circumpolar Antarctic pack ice 
(Rogers et al., 2013; as cited in Wursig et al., 2018). Most of the 
leopard seal population remains within the pack ice, but when the sea 
ice extent is minimal, leopard seals are restricted to coastal habitats 
(Meade et al., 2015; as cited in Wursig et al., 2018).
    These seals prey on penguins, other marine mammals, and 
zooplankton; this combination of apex predator and planktivore is 
unique for marine mammals. Due to the size of their mouth, leopard 
seals can take large-bodied prey including crabeater, Weddell, southern 
elephant seals, and fur seals.
    During three seasons (two Antarctic summers and one winter) of 
observation studies at Palmer Station, single leopard seals were 
occasionally observed lying on the ice in Arthur Harbor or swimming in 
Hero Inlet starting in late January until April of 2019. One additional 
sighting was recorded in July, and no leopard seals were observed again 
until November 19, 2019, when three were observed on the ice in Arthur 
Harbor. Occasional sightings continued from November 2019 through March 
of 2020. On March 31, a leopard seal was observed feeding on a 
crabeater seal in Hero Inlet (NSF, personal communication).

[[Page 46207]]

Weddell Seal

    Weddell seals are large pinnipeds weighing up to 600 kg with 
typical weights between 300 and 500 kg. Weddell seals aggregate on the 
ice to molt, and also sporadically dive during this period. After 
molting in fall-winter these seals disperse to sea; some individuals 
remain within the vicinity of their colonies, whereas other individuals 
disperse several hundreds of kilometers away and may not return to 
their colonies for several weeks.
    The Weddell seal's range includes coastal areas around the 
Antarctic continent and they are found in areas of both fast and pack 
ice. Weddell seals rarely venture into open, ice-free waters. Animals 
inhabiting the islands of the mostly ice-free northern Antarctic 
Peninsula are primarily coastal in their distribution.
    Weddell seals consume epipelagic (0-200 m), mesopelagic (200-1000 
m) and benthic prey. They can dive to depths over 600 m to reach the 
deeper prey items. Their diet consists mainly of fish but they also eat 
cephalopods, decapods and Antarctic krill. Their feeding/haul out 
pattern is diurnal; they haulout during the day and forage at night in 
response to the vertical migration of their prey (Andrews-Goff et al., 
2010; as cited in Wursig et al., 2018).
    Over three seasons (two Antarctic summers and one winter) of 
observation from January 21, 2019 through March 31, 2020, individual 
Weddell seals were observed on shore at Bonaparte Point from the end of 
February of 2019 through April of 2019. Weddell seals were observed 
swimming in Hero Inlet in early April 2019 on several occasions. No 
Weddell seals were sighted again until mid-September of 2019, when an 
individual was again observed on the ice in Hero Inlet. After September 
16, 2019, no Weddell seals were observed in the vicinity of Palmer 
Station until January 6, 2020; at that time a seal was observed in the 
vicinity of the outfall. As with 2019 observations, Weddell seal 
sightings at Bonaparte Pointe increased in mid- to late February of 
2020, and continued every day or every few days through March 27, 2020.
    As indicated above, all 17 species in Table 4 temporally and 
spatially co-occur with the activity to the degree that take is 
reasonably likely to occur, and we have proposed authorizing it.

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. 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 5.

           Table 5--Marine Mammal Hearing Groups (NMFS, 2018)
------------------------------------------------------------------------
              Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen      7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,   150 Hz to 16 kHz.
 toothed whales, beaked whales,
 bottlenose whales).
High-frequency (HF) cetaceans (true       275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true  50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea  60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Of the seventeen marine mammal species that may be present, six are 
classified as low-frequency cetaceans (i.e., all mysticete species), 
five are classified as mid-frequency cetaceans (i.e., all delphinid and 
ziphiid species and the sperm whale), one is classified as a high-
frequency cetacean species (i.e., hourglass dolphin.) and there is one 
species of otariid and 4 phocids.

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 section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species or 
stocks.
    Acoustic effects on marine mammals during the specified activity 
can occur from the underwater noise resulting from DTH pile 
installation, vibratory hammer removal, limited impact driving to seat 
piles, rock chipping, and the use of a hydrogrinder. The effects of 
underwater noise from NSF's proposed activities have the potential to 
result in

[[Page 46208]]

Level A or Level B harassment of marine mammals in the Project Area.

Description of Sound Sources

    The primary relevant stressor to marine mammals from the proposed 
activity is the introduction of noise into the aquatic environment; 
therefore, we focus our impact analysis on the effects of anthropogenic 
noise on marine mammals. To better understand the potential impacts, we 
describe sound source characteristics below. Specifically, we look at 
the following two ways to characterize sound: By its temporal (i.e., 
continuous or intermittent) and its pulse (i.e., impulsive or non-
impulsive) properties. Continuous sounds are those whose sound pressure 
level remains above that of the ambient sound, with negligibly small 
fluctuations in level (NIOSH, 1998; ANSI, 2005), while intermittent 
sounds are defined as sounds with interrupted levels of low or no sound 
(NIOSH, 1998). Impulsive sounds, such as those generated by impact pile 
driving, are typically transient, brief (< 1 sec), broadband, and 
consist of a high peak pressure with rapid rise time and rapid decay 
(ANSI, 1986; NIOSH, 1998). The majority of energy in pile impact pulses 
is at frequencies below 500 hertz (Hz). Impulsive sounds, by 
definition, are intermittent. Non-impulsive sounds, such as those 
generated by vibratory pile removal can be broadband, narrowband or 
tonal, brief or prolonged, and typically do not have a high peak sound 
pressure with rapid rise/decay time that impulsive sounds do (ANSI, 
1995; NIOSH, 1998). Non-impulsive sounds can be intermittent or 
continuous. Similar to impact pile driving, vibratory pile driving 
generates low frequency sounds. Vibratory pile driving is considered a 
non-impulsive, continuous source. DTH is a hybrid source- the rotary 
drill action produces non-impulsive, continuous sounds while the hammer 
function produces impulsive sounds. Discussion on the appropriate 
harassment threshold associated with these types of sources based on 
these characteristics can be found in the Estimated Take section.

Potential Effects of Pile Driving

    In general, the effects of sounds from pile driving to marine 
mammals might result in one or more of the following: Temporary or 
permanent hearing impairment, non-auditory physical or physiological 
effects, behavioral disturbance, and masking (Richardson et al., 1995; 
Nowacek et al., 2007; Southall et al., 2007). The potential for and 
magnitude of these effects are dependent on several factors, including 
receiver characteristics (e.g., age, size, depth of the marine mammal 
receiving the sound during exposure); the energy needed to drive the 
pile (usually related to pile size, depth driven, and substrate), the 
standoff distance between the pile and receiver; and the sound 
propagation properties of the environment.
    Impacts to marine mammals from pile driving activities are expected 
to result primarily from acoustic pathways. As such, the degree of 
effect is intrinsically related to the received level and duration of 
the sound exposure, which are in turn influenced by the distance 
between the animal and the source. The further away from the source, 
the less intense the exposure should be. The type of pile driving also 
influences the type of impacts, for example, exposure to impact pile 
driving or DTH may result in temporary or permanent hearing impairment, 
while auditory impacts are unlikely to result from exposure to 
vibratory pile driving. The substrate and depth of the habitat affect 
the sound propagation properties of the environment. Shallow 
environments are typically more structurally complex, which leads to 
rapid sound attenuation. In addition, substrates that are soft (e.g., 
sand) absorb or attenuate the sound more readily than hard substrates 
(e.g., rock) which may reflect the acoustic wave. Soft porous 
substrates also likely require less time to drive the pile, and 
possibly less forceful equipment, which ultimately decrease the 
intensity of the acoustic source.
    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.
    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, 2016b). 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 
(2018), there are numerous factors to consider when examining the 
consequence of TS, including, but not limited to, the signal temporal 
pattern (e.g., impulsive or non-impulsive), likelihood an individual 
would be exposed for a long enough duration or to a high enough level 
to induce a TS, the magnitude of the TS, time to recovery (seconds to 
minutes or hours to days), the frequency range of the exposure (i.e., 
spectral content), the hearing and vocalization frequency range of the 
exposed species relative to the signal's frequency spectrum (i.e., how 
animal uses sound within the frequency band of the signal; e.g., 
Kastelein et al., 2014), and the overlap between the animal and the 
source (e.g., spatial, temporal, and spectral).
    Permanent Threshold Shift-- 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).
    Temporary Threshold Shift--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 2015 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). As described in Finneran (2016), marine mammal studies 
have shown the amount of TTS increases with cumulative sound exposure 
level (SEL<INF>cum</INF>) in an accelerating fashion: At low exposures 
with lower SEL<INF>cum,</INF> the amount of TTS is typically small and 
the growth curves have shallow slopes. At exposures with higher 
SEL<INF>cum</INF>, the growth curves become steeper and approach linear 
relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and

[[Page 46209]]

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.
    Schlundt et al. (2000) performed a study exposing five bottlenose 
dolphins and two beluga whales (same individuals as Finneran's studies) 
to intense one second tones at different frequencies. The resulting 
levels of fatiguing stimuli necessary to induce 6 dB or larger masked 
TTSs were generally between 192 and 201 dB re: 1 microPascal ([mu]Pa). 
Dolphins began to exhibit altered behavior at levels of 178-193 dB re: 
1 [mu] Pa and above; beluga whales displayed altered behavior at 180-
196 dB re: 1 [mu] Pa and above. At the conclusion of the study, all 
thresholds were at baseline values.
    There are a limited number of studies investigating the potential 
for cetacean TTS from pile driving and only one has elicited a small 
amount of TTS in a single harbor porpoise individual (Kastelein et al., 
2015). However, captive bottlenose dolphins and beluga whales have 
exhibited changes in behavior when exposed to pulsed sounds (Finneran 
et al., 2000, 2002, and 2005). The animals tolerated high received 
levels of sound before exhibiting aversive behaviors. Experiments on a 
beluga whale showed that exposure to a single watergun impulse at a 
received level of 207 kiloPascal (kPa) (30 psi) p-p, which is 
equivalent to 228 dB p-p, resulted in a 7 and 6 dB TTS in the beluga 
whale at 0.4 and 30 kHz, respectively. Thresholds returned to within 2 
dB of the pre-exposure level within four minutes of the exposure 
(Finneran et al., 2002). Although the source level of pile driving from 
one hammer strike is expected to be lower than the single watergun 
impulse cited here, animals being exposed for a prolonged period to 
repeated hammer strikes could receive more sound exposure in terms of 
SEL than from the single watergun impulse (estimated at 188 dB re 1 
[mu]Pa\2\-s) in the aforementioned experiment (Finneran et al., 2002). 
Results of these studies suggest odontocetes are susceptible to TTS 
from pile driving, but that they seem to recover quickly from at least 
small amounts of TTS.
    Behavioral Responses--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. Disturbance may result in changing durations 
of surfacing and dives, number of blows per surfacing, or moving 
direction and/or speed; reduced/increased vocal activities; changing/
cessation of certain behavioral activities (such as socializing or 
feeding); visible startle response or aggressive behavior (such as 
tail/fluke slapping or jaw clapping); avoidance of areas where sound 
sources are located. Pinnipeds may increase their haul out time, 
possibly to avoid in-water disturbance (Thorson and Reyff, 2006). 
Behavioral responses to sound are highly variable and context-specific 
and any reactions depend on numerous intrinsic and extrinsic factors 
(e.g., species, state of maturity, experience, current activity, 
reproductive state, auditory sensitivity, time of day), as well as the 
interplay between factors (e.g., Richardson et al., 1995; Wartzok et 
al., 2003; Southall et al., 2007; Weilgart, 2007; Archer et al., 2010). 
Behavioral reactions can vary not only among individuals but also 
within an individual, depending on previous experience with a sound 
source, context, and numerous other factors (Ellison et al., 2012), and 
can vary depending on characteristics associated with the sound source 
(e.g., whether it is moving or stationary, number of sources, distance 
from the source). In general, pinnipeds seem more tolerant of, or at 
least habituate more quickly to, potentially disturbing underwater 
sound than do cetaceans, and generally seem to be less responsive to 
exposure to industrial sound than most cetaceans. Please see Appendices 
B-C of Southall et al., (2007) for a review of studies involving marine 
mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in marine mammal 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). There are broad categories of potential response, which we 
describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g.,

[[Page 46210]]

Frankel and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; 
Nowacek et al., 2004; Goldbogen et al., 2013a,b). Variations in dive 
behavior may reflect interruptions in biologically significant 
activities (e.g., foraging) or they may be of little biological 
significance. The impact of an alteration to dive behavior resulting 
from an acoustic exposure depends on what the animal is doing at the 
time of the exposure and the type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Respiratory variations 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, 2005b, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while North Atlantic 
right whales (Eubalaena glacialis) have been observed to shift the 
frequency content of their calls upward while reducing the rate of 
calling in areas of increased anthropogenic noise (Parks et al., 2007). 
In some cases, animals may cease sound production during production of 
aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
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 functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are

[[Page 46211]]

affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b, Wright et al., 2007) 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).
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al., 1995). Masking occurs when 
the receipt of a sound is interfered with by another coincident sound 
at similar frequencies and at similar or higher intensity, and may 
occur whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked. Given 
the limited vessel traffic near the Project Area and intermittent 
nature of pile installation and removal operations, any masking effects 
on marine mammals would likely be negligible.
    In-Water Construction Effects on Marine Mammal Habitat--NSF's 
construction activities could have localized, temporary impacts on 
marine mammal habitat by increasing in-water sound pressure levels and 
slightly decreasing water quality. Construction activities are of short 
duration and would likely have temporary impacts on marine mammal 
habitat through increases in underwater sound. Increased noise levels 
may affect acoustic habitat (see masking discussion above) and 
adversely affect marine mammal prey in the vicinity of the project area 
(see discussion below). During pile installation activities, elevated 
levels of underwater noise would ensonify Hero Inlet and nearby waters 
where both fish and mammals may occur and could affect foraging 
success. Additionally, marine mammals may avoid the area during 
construction, however, displacement due to noise is expected to be 
temporary and is not expected to result in long-term effects to the 
individuals or populations.
    Pile driving activities may temporarily increase turbidity 
resulting from suspended sediments. Any increases would be temporary, 
localized, and minimal. In general, turbidity associated with pile 
installation is localized to about a 25-foot (7.6 m) radius around the 
pile (Everitt et al., 1980). Cetaceans are not expected to be close 
enough to the project activity areas to experience effects of 
turbidity, and any small cetaceans and pinnipeds could avoid localized 
areas of turbidity. Therefore, the impact from increased turbidity 
levels is expected to be discountable to marine mammals. No turbidity 
impacts to Hero Inlet or nearby foraging habitats are anticipated.
    Sound may affect marine mammals and their habitat through impacts 
on the abundance, behavior, or distribution of prey species (e.g., 
crustaceans, cephalopods, fish, and zooplankton). Marine mammal prey 
varies by species, season, and location. Here, we describe studies 
regarding the effects of noise on known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). Depending on their hearing anatomy and peripheral sensory 
structures, which vary among species, fishes hear sounds using pressure 
and particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds that are especially strong and/or intermittent 
low-frequency sounds, 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

[[Page 46212]]

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).
    Sound pressure levels (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 construction activities at the 
Project Area would be temporary behavioral avoidance of the area. The 
duration of fish avoidance of this area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
that have the potential to cause behavioral harassment, depending on 
their distance from pile driving activities. However, in-air noise 
generated during pile driving activities at the pier should attenuate 
in air to less than levels that exceed NMFS established Level B 
harassment thresholds, before reaching the opposite side of Hero Inlet 
where seals may be on shore. A 2016 Final Rule for construction of a 
Navy Pier (81 FR 52614; August 9, 2016) estimated the greatest possible 
distances to airborne noise during installation of a 24'' steel pile 
(using a source level of 111 dB re 20 microPascals) as 168.3 m to the 
90 dB threshold for harbor seals and 53.2 m for all other seals (using 
a 100dB threshold). A 2019 Final Rule published for construction of the 
Liberty Development in Alaska estimated airborne noise during impact 
pile driving as 81 dB re 20 microPascals at 100 m and 93 dB re 20 
microPascals at 160 m (84 FR 70274; December 20, 2019). Therefore, 
based on the distance to Bonaparte Point, it is unlikely that animals 
hauled out across Hero Inlet will be exposed to levels above the NMFS 
Level B harassment threshold for disturbance.
    In summary, given the relatively small areas being affected (i.e., 
Hero Inlet and highly truncated sound fields extending out to 18 km), 
construction activities associated with the proposed action are not 
likely to have a permanent, adverse effect on any fish habitat, or 
populations of fish species. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity. Thus, we 
conclude that impacts of the specified activity are not likely to have 
more than short-term adverse effects on any prey habitat or populations 
of prey species. Further, any impacts to marine mammal habitat are not 
expected to result in significant or long-term consequences for 
individual marine mammals, or to contribute to adverse impacts on their 
populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of the acoustic sources (i.e., pile installation and removal equipment) 
has the potential to result in disruption of behavioral patterns for 
individual marine mammals. There is also some potential for auditory 
injury (Level A harassment) to result, primarily for mysticetes due to 
large PTS zones as well as for phocids and otariids due to haulouts in 
the vicinity of the Project Area. Auditory injury is unlikely to occur 
for high frequency or mid-frequency species. The proposed mitigation 
and monitoring measures are expected to minimize the severity of the 
taking to the extent practicable.
    As described previously, no mortality or serious injury 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 factors can 
contribute to a basic calculation to provide an initial prediction of 
takes, additional information that can qualitatively inform take 
estimates is also sometimes available (e.g., previous monitoring 
results or average group size). Below, we describe the factors 
considered here in more detail and present the proposed take estimate.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g., 
vibratory pile-driving, DTH) and above 160 dB re 1 [mu]Pa (rms) for 
non-explosive impulsive

[[Page 46213]]

(e.g., seismic airguns, impact pile driving) or intermittent (e.g., 
scientific sonar) sources.
    DTH pile installation includes drilling (non-impulsive sound) and 
hammering (impulsive sound) to penetrate rocky substrates (Denes et 
al., 2016; Denes et al., 2019; Reyff and Heyvaert 2019). DTH pile 
installation was initially thought be a primarily non-impulsive noise 
source. However, Denes et al., (2019) concluded from a study conducted 
in Virginia, that DTH pile installation should also be characterized as 
impulsive based on Southall et al., (2007), who stated that signals 
with a >3 dB difference in sound pressure level in a 0.035-second 
window compared to a 1-second window can be considered impulsive. 
Therefore, DTH pile installation is treated as both an impulsive and 
non-impulsive noise source. In order to evaluate Level A harassment, 
DTH pile installation activities are evaluated according to the 
impulsive criteria and using 160 dB rms. Level B harassment isopleths 
for DTH are determined by applying non-impulsive criteria and using the 
120 dB rms threshold which is also used for vibratory driving. This 
approach ensures that the largest ranges to effect for both Level A and 
Level B harassment are accounted for in the take estimation process for 
DTH.
    NSF's proposed activity includes the use of continuous (vibratory 
hammer, DTH pile installation, hydrogrinder) and impulsive (impact pile 
driving, DTH pile installation) sources, and therefore the 120 and 160 
dB re 1 [mu]Pa (rms) is/are applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). NSF's proposed activity includes the use 
of impulsive (i.e., impact hammer, DTH pile installation) and non-
impulsive (i.e., vibratory hammer, DTH pile installation, rock 
chipping, hydrogrinder) sources.
    These thresholds are provided in the Table 6. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 6--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 [mu]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.
    The sound field in the Project Area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., DTH pile installation, 
vibratory pile removal, limited impact for proofing purpose, rock 
chipping and use of hydrogrinders).
    The estimated sound source levels (SSL) proposed by NSF and used in 
this assessment are described below and are shown in Table 7. Appendix 
A in the application discusses in detail the sound source levels for 
all planned equipment. Sound levels from pile installation used in 
NSF's application came from the Caltrans Compendium (2015) or are based 
on empirical data collected from other sites with similar conditions 
(e.g., rock substrate where DTH driving would be used to install 
piles). NSF referenced two studies to arrive at SSLs for 24-in DTH pile 
installation. Noise studies from Kodiak ferry terminal (Denes et al., 
2016) and Skagway cruise ship terminal (Reyff and Heyvart, 2019; Reyff, 
2020). Results are shown in Table 7. NMFS has developed DTH pile 
installation guidelines which contain recommendations for appropriate 
SSLs. NSF applied these recommendations for 36-in DTH pile 
installation. However, NSF proposed to use the DTH pile installation 
SSLs shown in Table 7, which for 24-in DTH pile installation and 24-in 
sockets which are more conservative than those recommended by NMFS, and 
NMFS deemed this approach acceptable.
    NSF determined the SSLs for rock chipping based on underwater 
sounds measured for concrete demolition. NSF examined two sets of data 
available during the demolition of the Tappan Zee Bridge (state of New 
York) pier structures. NSF also considered the results from another 
study conducted by the Washington State Department of Transportation 
(WSDOT). Results from that analysis are shown in Table 7.
    The U.S. Navy has assessed sound levels of the use of a 
hydrogrinder through underwater measurements (U.S. Navy 2018). The Navy 
measurements were reported in 1/1-octave frequency bands from 125 to 
8,000 Hz for the helmet position that was assumed to be

[[Page 46214]]

0.5 to 1 meter from the hydraulic grinder operation. The overall 
unweighted sound level was computed to be 167.5 dB at 0.5 to 1 meter. 
Source sound levels in this report are provided for 10-m distances. 
Since this is a point source of sound, spherical spreading 20 Log TL 
coefficient results in a source sound level of 142 to 148 dB at 10 
meters (see Appendix A in the application). A value of 146 dB at 10m 
has been used to estimate marine mammal take associated with these 
tools.
    NSF assumed that installation of approximately one to two piles 
would occur over a 12-hour work day. To be precautionary in calculating 
isopleths, this application assumes two installation activities would 
occur simultaneously. For example, two 36-in piles installed 
simultaneously or one 36-in pile and one 24-in pile. Brief impact pile 
driving of about 10 strikes may be used to seat the piles. A likely 
approach to installing 36-in piles would be to use DTH to install two 
36-in piles simultaneously; one 36-in pile would be installed to 20-ft 
socket depth while a second 36-in abutment pile would be installed to a 
30-ft socket depth. The abutment piles require additional depth to 
support lateral loads and to provide side friction against ice uplift 
that could occur at the shoreline. It is also possible that both 36-in 
piles may be installed simultaneously to 20-ft socket.
    Rock chipping may be required to level pile areas and would 
normally occur on the same day as DTH pile installation, if possible. 
If rock chipping is conducted separately from DTH pile installation, 
takes are accounted for by using the area ensonified during DTH pile 
installation to calculate takes. This precautionary approach 
overestimates takes that could occur if only rock chipping is conducted 
by itself. Rock chipping is considered to be an impulsive source.
    Existing sheetpile would be removed through vibratory extraction. 
In some instances it may be necessary to remove piles by cutting them 
off at the mudline using underwater hand cutting tools. Such activity 
would occur on the same days as vibratory extraction. Cutting piles off 
at the mudline would result in less underwater noise than vibratory 
removal. To be precautionary, estimated marine mammal takes were 
calculated by assuming all piles were removed by vibratory extraction.

                                                              Table 7--Sound Source Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Measured sound levels \1\
----------------------------------------------------------------------------------------------------------------                  Source
                    Activity                          Peak             RMS           SEL \2\           TL
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       24-in Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH pile installation..........................             190             166             154              15  Denes et al., (2016).
Vibratory Driving \4\..........................             170             165             165              15  Caltrans (2015).
Impact Driving.................................             195             181             168              15  Caltrans (2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       36-in Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH pile installation..........................             194             166             164              15  The DTH sound source proxy of 164 dB
                                                                                                                  SEL is from 42-in piles, Reyff (2020)
                                                                                                                  and Denes et al., (2019).
Vibratory Driving..............................             180             170             170              15  Caltrans (2015).
Impact Driving.................................             210             193             183              15  Caltrans (2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           H Piles inserted in 24-in. Sockets
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH pile installation..........................             190             166             154              15  Denes et al., (2016).
Vibratory Driving..............................             170             165             165              15  Caltrans (2015).
Impact Driving.................................             195             180             170              15  Caltrans (2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Removal of 24-in Template Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Driving..............................             170             165             165              15  Caltrans (2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Removal of Sheet Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Driving..............................             175             160             160              15  Caltrans (2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Rock Chipping
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hydraulic Breaker..............................             197             184             175              22  Tappan Zee Bridge 6 7.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Anode Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hydro-grinder..................................  ..............             146  ..............              20  U.S. Navy (2008).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ See Appendix A in application for references and discussion of all sound sources.
\2\ SEL is single strike for impact driving and DTH pile installation. SEL for vibratory installation is per second.
\4\ Includes removal of 24-in. piles
\5\ While it is possible the socket depth would be only 20 feet, this application assumes the greater depth to be precautionary.
\6\ Reyff, J. 2018. Demolition of Existing Tappan Zee Bridge. Summary of Underwater Sound Measurements for Mechanical Demolition of Concrete Pile Caps
  at Piers 114 and 115, Circular Caisson at Pier 166, and Rectangular Caisson at Pier 170. To David Capobianco, New York State Thruway Authority.
  December 18, 2020.
\7\ Reyff, J. 2018. Demolition of Existing Tappan Zee Bridge Subject: Summary of Underwater Sound Measurements for Mechanical Demolition of Ice Breakers
  at Piers 173 and 169. To Kristine Edwards, New York State Thruway Authority. January 10, 2018.


[[Page 46215]]

    When the sound fields from two or more concurrent pile installation 
activities overlap, the decibel addition of continuous noise sources 
results in much larger zone sizes than a single source. Decibel 
addition is not a consideration when sound fields do not overlap. The 
increased SLs potentially associated with two concurrent sources with 
overlapping sound fields are shown in Table 8 (WSDOT 2015). Decibel 
addition is only applicable to continuous sources. According to NMFS 
guidance the SL for continuous sounds from DTH pile installation is 166 
dB regardless of the size of the pile. Under decibel addition, 
simultaneous DTH pile installation activities would use a SL of 169 
(166 + 3) to derive the isopleth for the Level B harassment zone.

                                  Table 8--Simultaneous Source Decibel Addition
----------------------------------------------------------------------------------------------------------------
           Hammer types               Difference in SSL           Level A zones              Level B zones
----------------------------------------------------------------------------------------------------------------
Vibratory, Impact.................  Any..................  Use impact zones..........  Use largest zone.
Impact, Impact....................  Any..................  Use zones for each pile     Use zone for each pile
                                                            size and number of          size.
                                                            strikes.
Vibratory, Vibratory..............  0 or 1 dB............  Add 3 dB to the higher      Add 3 dB to the higher
                                                            source level.               source level.
                                    2 or 3 dB............  Add 2 dB to the higher      Add 2 dB to the higher
                                                            source level.               source level.
                                    4 to 9 dB............  Add 1 dB to the higher      Add 1 dB to the higher
                                                            source level.               source level.
                                    10 dB or more........  Add 0 dB to the higher      Add 0 dB to the higher
                                                            source level.               source level.
----------------------------------------------------------------------------------------------------------------

Level B Harassment Zones

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

TL = B * Log10 (R1/R2),

Where:

TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, which is the most appropriate 
assumption for NSF's proposed activity in the absence of specific 
modelling. Level B harassment isopleths are shown in Table 15 and Table 
16.

Level A Harassment Zones

    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 those 
planned for this project, NMFS User Spreadsheet predicts the 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, and the resulting isopleths are reported below. Tables 9, 
10 and 11 shows User inputs for single sound sources while Tables 12, 
13, and 14 contain User inputs for simultaneous sources. The resulting 
Level A harassment isopleths for non-simultaneous activities and 
simultaneous activities are shown in Table 15 and Table 16 
respectively. Level B harassment isopleths for simultaneous DTH pile 
installation utilize a 169 dB SL and corresponding isopleths are shown 
in Table 16. Note that strike numbers for DTH pile installation were 
derived by applying the duration required to drive a single pile 
(minutes), the number of piles driven per day, and the strike rate 
(average strikes per second) rates to arrive at the total number of 
strikes in a 24-hour period. A rate of 10 strikes per second was 
assumed.

 Table 9--NMFS Technical Guidance (2020) User Spreadsheet Inputs To Calculate PTS Isopleths for Non-Simultaneous Vibratory Pile Installation Activities
                                                                    and Hydrogrinding
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            36-in (dock     RHIB fender   24-in template    24-in wave    24-in template    Sheet pile         Anode
----------------------------------------- dock abutment)-   piles 24-in     10' socket      attenuator     pile removal       removal      installation
                                                in       --------------------------------    piles-in    --------------------------------     (hydro-
                                         ----------------                                ----------------                                    grinding)
                                                             A.1) Non-       A.1) Non-                       A.1) Non-       A.1) Non-   ---------------
          Spreadsheet tab used               A.1) Non-     impul, stat,    impul, stat,      A.1) Non-     impul, stat,    impul, stat,      A.1) Non-
                                           impul, stat,        cont.           cont.       impul, stat,        cont.           cont.       impul, stat,
                                               cont.                                           cont.                                           cont.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Level (SPL RMS)..................             170             165             165             165             165             160             146
15 Transmission Loss Coefficient........              15              15              15              15              15              15              20
Weighting Factor Adjustment (kHz).......             2.5             2.5             2.5             2.5             2.5             2.5             2.5
Time to install/remove single pile                    30              30              30              30              30              30             120
 (minutes)..............................
Piles to install/remove per day.........               1               1               2               1              16              16               1
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 46216]]


 Table 10--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Non-Simultaneous
                                       Impact Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
                                                                   36-in (dock,     24-in RHIB     Rock chipping
----------------------------------------------------------------- dock abutment)    (template,   ---------------
                                                                 ----------------      wave
                                                                                    attenuator)    E) Stationary
                      Spreadsheet Tab Used                          E.1) Impact  ----------------     source:
                                                                   pile driving     E.1) Impact     impulsive,
                                                                                   pile driving    intermittent
----------------------------------------------------------------------------------------------------------------
Source Level (Single Strike/shot SEL)...........................             183             168             197
Transmission Loss Coefficient...................................              15              15              22
Weighting Factor Adjustment (kHz)...............................               2               2               0
Number of pulses in 1-hr period.................................              10              10           2,700
Piles per day...................................................               1               1  ..............
----------------------------------------------------------------------------------------------------------------


 Table 11--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Non-Simultaneous
                                        DTH Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
                                                                  36-in dock 20'  Dock abutment-    24-in RHIB,
-----------------------------------------------------------------     socket         36-in 30'    template, wave
                                                                 ----------------     socket        attenuator
                                                                                 -------------------------------
                      Spreadsheet tab used                         E.2) DTH pile   E.2) DTH pile   E.2) DTH pile
                                                                      driving         driving         driving
----------------------------------------------------------------------------------------------------------------
Source Level (Single Strike/Shot SEL)...........................             164             164             154
Transmission Loss Coefficient...................................              15              15              15
Strike rate (Strikes/sec).......................................              10              10              10
Duration (min)..................................................             345             518             345
Weighting Factor Adjustment (kHz)...............................               2               2               2
SStrikes/pile...................................................         207,000         310,500         207,000
Piles to install/remove per day.................................               1               1               1
----------------------------------------------------------------------------------------------------------------


   Table 12--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Simultaneous
                                     Vibratory Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
                                  36-in dock 20'    RHIB fender                     24-in wave      24-in wave
---------------------------------   socket x 2     piles 24-in x                    attenuator      attenuator
                                   dock abutment         2                           piles-10'       piles-20'
                                 -------------------------------- 24-in template    socket x 2      socket x 2
                                                                  10' socket x 4 -------------------------------
      Spreadsheet tab used           A.1) Non-       A.1) Non-                       A.1) Non-       A.1) Non-
                                   impul, stat,    impul, stat,                    impul, stat,    impul, stat,
                                       cont.           cont.                           cont.           cont.
----------------------------------------------------------------------------------------------------------------
Source Level (SPL RMS)..........             173             168             168             168             168
Transmission Loss Coefficient...              15              15              15              15              15
Weighting Factor Adjustment                  2.5             2.5             2.5             2.5             2.5
 (kHz)..........................
Time to install/remove single                 30              30              15              30              30
 pile (minutes).................
Piles to install/remove per day.               2               2               4               2               2
----------------------------------------------------------------------------------------------------------------


   Table 13--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Simultaneous
                                       Impact Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
                                                    36-in (dock     RHIB fender   24-in template    24-in wave
-------------------------------------------------  20' socket x    piles 24-in x  10' socket x 4    attenuator
                                                    2) or dock           2       ----------------    piles x 2
                                                  abutment-36-in ----------------                ---------------
                                                    30' and 20'
              Spreadsheet tab used                    socket                        E.1) Impact
                                                 ----------------   E.1) Impact    pile driving     E.1) Impact
                                                    E.1) Impact    pile driving                    pile driving
                                                   pile driving
----------------------------------------------------------------------------------------------------------------
Source Level (Single Strike/shot SEL)...........             183             168             168             168
Transmission Loss Coefficient...................              15              15              15              15
Weighting Factor Adjustment (kHz)...............               2               2               2               2
Strikes/pile....................................              10              10              10              10
Piles per day...................................               2               2               4               2
----------------------------------------------------------------------------------------------------------------


[[Page 46217]]


 Table 14--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Simultaneous DTH
                                          Pile Installation Activities
----------------------------------------------------------------------------------------------------------------
                                                  36-in dock 20'  Dock abutment-  24-in template    24-in wave
-------------------------------------------------   socket x 2     36-in 30' and  10' socket x 4    attenuator
                                                 ----------------   20' socket   ----------------   piles- 10'
                                                                 ----------------                   socket x 2/
                                                                                                    RHIB fender
                                                                                                   piles 24-in x
              Spreadsheet tab used                 E.2) DTH pile   E.2) DTH pile   E.2) DTH pile         2
                                                      driving         driving         driving    ---------------
                                                                                                   E.2) DTH pile
                                                                                                      driving
----------------------------------------------------------------------------------------------------------------
Source Level (Single Strike/Shot SEL)...........             164             164             154             154
Transmission Loss Coefficient...................              15              15              15              15
Strike rate (Strikes/sec).......................              10              10              10              10
Duration (min)..................................             345             430           172.5             345
Weighting Factor Adjustment (kHz)...............               2               2               2               2
Strikes/pile....................................         414,000         517,500         103,500         207,000
Piles to install per day........................               2               2               4               2
----------------------------------------------------------------------------------------------------------------


                          Table 15--Level A and Level B Harassment Isopleths for Non-Simultaneous Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Level A harassment zones (m) based on SELcum
                                                                                ------------------------------------------------------------   Level B
                                                                                              Cetaceans                     Pinnipeds         harassment
                                                                                ------------------------------------------------------------   zone (m)
                                                                                     LF          MF          HF          PW          OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock, 36-in Dia. Pile Installation, 20'        DTH Pile Drilling...............       1,891          67       2,253       1,012          74       11,659
 Socket Depth--1 pile/day.
Dock Abutment, 36-in Dia. Pile Installation,   DTH Pile Drilling...............       2,478          88       2,951       1,326          97       11,659
 30' Socket Depth--1 pile/day.
RHIB Fender Piles, 24-in Dia. Pile             DTH Pile Drilling...............         407          15         485         218          16       11,659
 Installation, 20' Socket--1 pile/day.
24-in Dia. Template Piles, 10' Socket Depth--  DTH Pile Drilling...............         407          15         485         218          16       11,659
 2 piles/day.
24-in Dia Wave Attenuator Piles, 20' Socket    DTH Pile Drilling...............         407          15         485         218          16       11,659
 Depth--1 pile/day.
Retaining Wall HP Pile inserted in Drilled 24- DTH Pile Drilling...............         407          15         485         218          16       11,659
 in Dia Sockets, 20' Socket Depth--1 pile/day.
Removal of 24-in Dia. Template Piles--16       Vibratory.......................          51           5          75          31           2       10,000
 piles.
Removal of Sheet Piles.......................  Vibratory.......................          23           2          35          14           1        4,642
Rock Chipping/Floor Preparation..............  Hydraulic Breaker...............         403          50         716         204          29          123
Anode Installation...........................  Hydrogrinder....................         1.9         0.3         2.5         1.3         0.2          200
--------------------------------------------------------------------------------------------------------------------------------------------------------


                            Table 16--Level A and Level B Harassment Isopleths for Simultaneous Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Level A harassment zones (m) based on SELcum
                                                                                ------------------------------------------------------------   Level B
           Daily activity scenario                    Installation method                     Cetaceans                     Pinnipeds         harassment
                                                                                ------------------------------------------------------------   zone (m)
                                                                                     LF          MF          HF          PW          OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock, 36-in Dia. Pile Installation, 20'        DTH Pile Installation...........       3,002         107       3,576       1,607         117       18,478
 Socket Depth--2 pile/day.
Dock Abutment, 36-in Dia. Pile Installation,                                          3,484         124       4,149       1,864         136       18,478
 30' Socket Depth and 36-in Dia. Pile 20'
 Socket Depth.
RHIB Fender Piles, 24-in Dia. Pile                                                      647          23         770         346          25       18,478
 Installation, 20' Socket--2 pile/day.
24-in Dia. Template Piles, 10' Socket Depth--
 4 piles/day.
24-in Dia Wave Attenuator Piles, 20' Socket
 Depth--2 pile/day.
Retaining Wall--HP Pile inserted in Drilled
 24-in Dia Sockets, 20' Socket Depth--2 piles/
 day.
Dock, 36-in Dia. Pile Installation, 20'                                               2,011          72       2,395       1,076          78       18,478
 Socket Depth--1 pile/day and Wave
 Attenuator, 24-in Dia. Pile Installation,
 20' Socket--1 pile/day.
Dock 36-in Dia. Pile Installation 30' Socket                                          2,885         103       3,436       1,544         133       18,478
 Depth and 24-in Dia Pile Installation 20'
 Socket Depth.
36-in Dock 20' socket x 2 Dock Abutment......  Vibratory Installation..........          43           4          64          26           2       34,146
RHIB Fender Piles 24-in x 2..................                                            20           2          30          12           1       15,849
24-in template 10' socket x 4................
24-in wave attenuator piles-10' socket x 2...                                          31.8           3          47          19         1.4
24-in wave attenuator piles-20' socket x 2...
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 46218]]

    The calculated area that would be ensonified by single or multiple 
pile installation and removal sound sources is calculated based on the 
distance from the Palmer Station Pier installation location to the edge 
of the isopleth for Level B harassment and for each hearing group for 
Level A harassment. The scenario with the largest zone is used to 
estimate potential marine mammal exposures and those areas are shown in 
Table 17. The Palmer Station Pier is located in a narrow portion of 
Hero Inlet and the areas potentially ensonified above Level A and Level 
B harassment thresholds is truncated by the location of land masses 
including assorted islands (i.e., shadow effect).
    Table 16 shows the construction scenario (installation of two 36-in 
piles, one at 30- ft and a second at 20-ft socket depth) that results 
in the largest PTS zone isopleths while Table 17 shows the areas of the 
corresponding zones ensonified areas. The maximum Level A harassment 
distance would be 1,864 m (1.4 km\2\) for phocids in water (PW), 3,484m 
(3.38 km\2\) for LF cetaceans, and 4,149m (4.4 km\2\) for HF cetaceans 
(although HF cetaceans are considered rare in the Project Area and 
Level A harassment takes are not proposed). The largest Level B 
harassment isopleth is associated with simultaneous DTH pile 
installation and would be at a distance of 18,478 m from the source 
covering an area of 54.99 m.

                          Table 17--Harassment Zone Areas Used for Take Estimation \1\
----------------------------------------------------------------------------------------------------------------
                                                             Level A max area   Level A max area   Level B area
                 Pile type                    Total piles      cetaceans\3\       pinnipeds\3\      all species
                                                                 (km\2\)            (km\2\)           (km\2\)
----------------------------------------------------------------------------------------------------------------
36-in piles (one @30-ft socket depth and                18     3.38 (LF), 4.4     1.4 (PW), 0.03           54.99
 one @20-ft socket depth).................               4    (HF), 0.03 (MF)               (OW)
32-in piles (Bent 1)......................
Pile Removal (24-in)......................              16  0.006 (LF), 0.012         0.002 (PW)           20.78
                                                                (MF), ~0 (MF)
Sheetpile Removal.........................              20  0.001 (LF), 0.003        0.0006 (PW)            5.27
                                                                (HF), ~0 (MF)
Anode Installation........................             n/a                n/a                n/a            0.07
Rock Chipping.............................             unk
                                           ---------------------------------------------------------------------
    Total.................................              88
----------------------------------------------------------------------------------------------------------------
\1\ Assumes simultaneous installation (i.e., two pile installations occurring at the same time).

Marine Mammal Occurrence and Take Estimation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    The approach by which the information provided above is brought 
together to produce a quantitative take estimate is described here. For 
some species only observational data is available and is used to 
estimate take. For marine mammals with known density information 
estimated harassment take numbers are calculated using the following 
equation (summed across each type of activity):

Estimated take = animal density x ensonified area x operating days

    As noted above we used the most conservative option for estimating 
ensonified area for each activity. We also used conservative estimates 
of the number of days of work for each activity.
    Takes were estimated by considering the density of marine mammals 
per km\2\ multiplied by the potential area ensonified (km\2\) and the 
number of days the noise could occur during in-water construction. The 
Project Area is located in the nearshore environment relative to the 
Antarctic Peninsula as defined by data reported in Santora et al. 
(2009). Sources for density data and average group sizes are found in 
Table 6-3 in the application. For some species only offshore data were 
available, for some only nearshore data, and for others data existed 
for both areas. Offshore densities were used to estimate take for eight 
species. Nearshore densities were unavailable for three species. 
Nearshore densities were used to calculate take for four species. Data 
from these offshore sources results in averaging across large portions 
of the region. NSF notes that these data are from areas where cetaceans 
may occur in significantly greater densities than the Palmer Pier 
Project Area due to expected increased faunal density along the sea ice 
edge and shelf-frontal features in the southern oceans. These 
oceanographic features are not present within the Project Area, so 
lower densities of cetaceans are expected within close proximity to 
Palmer Station. Therefore, the offshore densities may represent an 
overestimate of anticipated densities within the Palmer Station Project 
Area.
    NSF estimated Level A harassment takes by multiplying the Level A 
harassment areas by the species density (nearshore or offshore as 
described above) which was then multiplied by the expected number of 
pile driving days for each activity type. The exposures for each 
activity were added to arrive at calculated Level A harassment take 
number as shown in Table 20. In cases where both nearshore and offshore 
densities were available, the higher of the two densities is used to 
estimate take. Note that designated shutdown zones cover all of the 
Level A harassment zones with the exception of pinnipeds, where the 
zones in some cases are larger than the proposed 50-m shutdown zone. 
However, we are proposing to authorize take for some cetacean species 
where the calculated Level A harassment take is significant, and the 
large PTS zone sizes could allow animals to enter into these zones 
without being observed by protected species observers (PSOs).
    A similar approach was employed to derive estimated take by Level B 
harassment. The Level B harassment zones are determined by taking the 
total area of the Level B harassment zones (54.99 km\2\; 20.78 km\2\; 
5.27 km\2\; 0.07 km\2\) and subtracting the Level A harassment areas as 
defined by activity type and hearing group.
    The Level B harassment zone area was multiplied by the highest 
density for a species (nearshore or offshore as described above) which 
was multiplied by the expected number of pile driving days for each 
activity type. The exposures for each activity were summed to arrive at 
the calculated Level B harassment take numbers as shown in Table 18. 
Additional detailed information may be found in Appendix B of the 
application.

[[Page 46219]]



      Table 18--Calculated Level A and Level B Harassment Exposures
------------------------------------------------------------------------
                                              Level A         Level B
                                            harassment      harassment
                 Species                       total           total
                                             exposures       exposures
------------------------------------------------------------------------
Antarctic Minke Whale (LF)..............           15.23          312.25
Arnoux's Beaked Whale (MF)..............          0.0001            0.14
Blue Whale (LF).........................          0.0081            0.17
Fin Whale (LF)..........................           13.74          281.70
Hourglass Dolphin (HF)..................            0.32            4.94
Humpback Whale (LF).....................            5.91          121.21
Killer Whale (MF).......................            0.04          111.70
Long-finned Pilot Whale (MF)............            0.01           28.19
Southern Bottlenose Whale (MF)..........           0.009           23.55
Sei Whale (LF)..........................            0.04            0.84
Southern Right Whale (LF)...............            0.07            1.34
Sperm Whale (MF)........................            0.02           16.73
Antarctic Fur Seal (OW).................            0.15          356.50
Crabeater Seal (PW).....................          119.07         6128.78
Southern Elephant Seal (PW).............            0.02            1.04
Leopard Seal (PW).......................            0.02            1.04
Weddell Seal (PW).......................            3.65          187.97
------------------------------------------------------------------------

    In addition to considering density data presented in the 
literature, recent marine mammal observation data from Hero Inlet and 
nearby areas between January 21, 2019 and March 31, 2020 are also 
considered in the take estimates. Observations within Hero Inlet near 
Palmer Station included animals observed in the waters of Hero Inlet, 
or hauled out at Gamage Point or Bonaparte Point. Gamage Point is 
approximately 100 m west of the pier area on Anvil Island while 
Bonaparte Point is located across Hero Inlet 135m southeast of the Pier 
area. Table 19 shows a comparison between observational data from the 
Project Area (NSF, personal communication) and the calculated takes by 
Level A harassment based on density data.

  Table 19--Comparison of Observation Data From Hero Inlet, Gamage Point and Bonaparte Point 2019-2020 to Total
                     Level A Harassment Exposure Estimates Calculated Based on Density Data
----------------------------------------------------------------------------------------------------------------
                                                                    January 21-     October 12,
                                                                  March 28, 2019  2019-March 31,   Density-based
                             Species                               observations        2020            total
                                                                                   observations      exposures
----------------------------------------------------------------------------------------------------------------
Humpback Whale (LF).............................................               0               0            5.91
Antarctic Fur Seal (OW).........................................              73              70            0.15
Crabeater Seal (PW).............................................              20              24          119.07
Southern Elephant Seal (PW).....................................               1               0            0.02
Leopard Seal (PW)...............................................               3               2            0.02
Weddell Seal (PW)...............................................               8               6            3.65
----------------------------------------------------------------------------------------------------------------

    Comparing the estimated exposures based on pinniped densities, 
number of days, and the Level A Harassment zone to local observational 
data from Palmer Station over two multiple-month periods suggests that 
some pinniped species were potentially observed at a greater rate than 
would be expected from density information. In the interest of 
generating a more conservative estimate that will ensure coverage for 
any marine mammals encountered, the number of Antarctic fur, leopard 
and Weddell seal takes have been increased to reflect the number 
individuals observed in Hero Inlet.
    Table 20 compares the number of calculated and proposed Level A and 
B harassment takes for each species. Level B harassment takes for 
Arnoux's beaked whale, blue whale, hourglass dolphin, sei whale, and 
Southern right whale have been adjusted based on group size such that a 
higher level of Level B harassment take is proposed than was projected 
solely based on densities. Arnoux's beaked whales often occur in groups 
of 6-10 and occasionally up to 50 or more (Balcomb 1989). As a 
precautionary measure NSF requested and NMFS has proposed authorizing 
12 takes of this species by Level B harassment. Classified as HF 
cetaceans, these beaked whales have a relatively large Level A 
harassment zone that extends to as much as 4,149 m. However, calculated 
take by Level A harassment is fractional and furthermore, this is a 
deep diving and deep foraging species and it would be unlikely that 
animals would congregate in a Level A harassment zone long enough to 
accrue enough energy to experience PTS. Therefore, no Level A take was 
requested by NSF nor is proposed for authorization by NMFS. Blue whales 
are unlikely to be found in the Project Area. However, NSF requested 
and NMFS conservatively proposes to authorize two Level B harassment 
takes based on one average group size (NMFS, 2020). Hourglass Dolphins 
group size is generally 2-6 individuals with groups of up to 25 
observed (Santora 2012). Classified as HF cetaceans, these dolphins 
have a relatively large Level A harassment zone that extends to 4,149 
m. However, local observational data sets have not recorded a single 
animal and the species tends to be found in waters close to the 
Antarctic Convergence. Given this information NMFS proposes to

[[Page 46220]]

authorize 25 takes by Level B harassment which is a reduction from 60 
takes requested by NSF. Level A harassment takes are not expected or 
authorized since the dolphin species is highly mobile and is unlikely 
to remain in the zone long enough to experience PTS. Sei whales have an 
average group size of 6 (NMFS 2020) and generally inhabit continental 
shelf and slope waters far from coastlines. They are unlikely to occur 
but as a precautionary measure NSF has requested and NMFS proposes to 
authorize 6 takes by Level B harassment. Takes by Level A harassment 
are not expected or proposed for authorization. Southern right whales 
live in groups of up to 20 individuals, but are more commonly found in 
groups of two or three, unless at feeding grounds. Observational 
surveys near Palmer Station did not record the presence of these 
whales. Therefore, NSF requested and NMFS conservatively proposes to 
authorize 20 takes of Southern right whale by Level B harassment. No 
take by Level A harassment is anticipated or proposed for 
authorization.
    As discussed above, the proposed takes have been adjusted from the 
calculated takes based on observation data as summarized in Table 19. 
Local observers recorded 73 and 70 Antarctic fur seals in 2019 and 2020 
respectively located in close proximity to the pier during months when 
construction would take place. As a precaution, the number of takes by 
Level A harassment requested by NSF and proposed for authorization by 
NMFS has been increased beyond the calculated density value to 80. 
Similarly, three leopard seals were observed in 2019 and two were 
recorded in 2020. To be precautionary, NSF requested and NMFS is 
proposing to authorize 5 leopard seal takes by Level B. Further, since 
leopard seals are thought to be more likely to spend more time in the 
immediate vicinity (i.e., not as likely to travel through as the 
cetacean species discussed above) and potentially enough time in the 
Level A harassment zone to incur PTS, NMFS is also proposing to 
authorize 5 takes by Level A harassment. Finally, eight and six Weddell 
seals were observed in 2019 and 2020, respectively. Given this 
information, and again to be precautionary NSF has requested and NMFS 
is proposing to authorize 10 takes by Level A harassment. Finally, NMFS 
has proposed a single take by Level A harassment of Southern elephant 
seal. Like all seals authorized for take there are driving scenarios 
where the PTS isopleth would be larger than 50-m pinniped shutdown 
zone. While only one elephant seal has been observed near Palmer 
Station, it could occur in the Level A harassment zone.

           Table 20--Proposed Takes by Level A and Level B Harassment Compared to Calculated Exposures
----------------------------------------------------------------------------------------------------------------
                                    Calculated                      Calculated
                                      Level A     Proposed Level      Level B     Proposed Level     Takes as
             Species                harassment     A harassment     harassment     B harassment     percent of
                                     exposures         take          exposures         take          abundance
----------------------------------------------------------------------------------------------------------------
Antarctic Minke Whale (LF)......           15.23              15          312.25             312            1.80
Arnoux's Beaked Whale (MF) a....            0.00               0            0.14              12         Unknown
Blue Whale (LF) a...............            0.01               0            0.17               2            0.12
Fin Whale (LF)..................           13.74              14          281.70             282            6.33
Hourglass Dolphin (HF) a........            0.32               0            4.94              25            0.01
Humpback Whale (LF).............            5.91               6          121.21             121            1.34
Killer Whale (MF)...............            0.04               0           111.7             112            0.45
Long-finned Pilot Whale (MF)....            0.01               0           28.19              28            0.01
Southern Bottlenose Whale (MF)..            0.01               0           23.55              24            0.04
Sei Whale (LF) a................            0.04               0            0.84               6            0.96
Southern Right Whale (LF) a.....            0.07               0            1.34              20            1.13
Sperm Whale (MF)................            0.02               0           16.73              17            0.14
Antarctic Fur Seal (OW).........            0.15            b 80           356.5             357            0.02
Crabeater Seal (PW).............          119.07             120        6,128.78           6,129            0.12
Southern Elephant Seal (PW).....            0.02               1            1.04               1           <0.01
Leopard Seal (PW)...............            0.02             b 5            1.04               1           <0.01
Weddell Seal (PW)...............            3.65            b 10          187.97             188            0.04
----------------------------------------------------------------------------------------------------------------
\a\ Level B harassment takes increased to account for group size assuming one group is encountered during the
  project.
\b\ Increased from calculated exposures due to local observational data.

    Table 20 also shows the proposed take by harassment for all species 
as a percentage of stock abundance.

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, 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

[[Page 46221]]

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 proposed in the IHA:
    <bullet> NSF must avoid direct physical interaction with marine 
mammals during construction activities. If a marine mammal comes within 
10 m of such activity, operations must cease and vessels must reduce 
speed to the minimum level required to maintain steerage and safe 
working conditions;
    <bullet> Training would occur between construction supervisors and 
crews and the PSO team and relevant NSF staff prior to the start of all 
pile driving and construction activities, and when new personnel join 
the work, in order to explain responsibilities, communication 
procedures, marine mammal monitoring protocol, and operational 
procedures are clearly understood;
    <bullet> Pile driving activities must be halted upon observation of 
either a species for which incidental take is not authorized or a 
species for which incidental take has been authorized but the 
authorized number of takes has been met, entering or within the 
harassment zone;
    <bullet> NSF will establish and implement a shutdown zone of 50 m 
for fur seals under all pile driving scenarios. 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). Shutdown zones 
typically vary based on the activity type and marine mammal hearing 
group. Shutdown zones for cetaceans and other pinnipeds are based on 
Level A harassment isopleths shown in Table 17. Based on observation 
data, fur seals are known to swim up Hero Inlet (approximately 135 m 
wide) to haul out. The proposed 50-m shutdown zone for fur seals can 
safely be observed, would prevent injury to seals while still allowing 
seals to move up the inlet where they may haul out on land, and would 
allow construction to continue safely and efficiently;
    <bullet> Shutdown zones have been established for all hearing 
groups under all driving scenarios as shown in Tables 21 and 22 and are 
based on calculated Level A harassment zones;
    <bullet> Monitoring must take place from 30 minutes prior to 
initiation of pile driving activity through 30 minutes post-completion 
of pile driving activity. Pre-start clearance monitoring must be 
conducted during periods of visibility sufficient for the lead PSO to 
determine the shutdown zones clear of marine mammals. Pile driving may 
commence following 30 minutes of observation when the determination is 
made;
    <bullet> If the Level A harassment shutdown zones are not visible 
due to poor environmental conditions (e.g., excessive wind or fog, high 
Beaufort state), pile installation would cease until the entirety of 
the Level A harassment shutdown zones is observable;
    <bullet> If pile driving is delayed or halted due to the presence 
of a marine mammal, the activity may not commence or resume until 
either the animal has voluntarily exited and been visually confirmed 
beyond the shutdown zone or 15 minutes have passed without re-detection 
of the animal;
    <bullet> If impact driving should be needed (i.e., for proofing) 
NSF must use soft start techniques when impact pile driving. Soft start 
requires contractors to provide an initial set of three strikes at 
reduced energy, followed by a 30-second waiting period, then two 
subsequent reduced-energy strike sets. A soft start must be implemented 
at the start of each day that begins with impact pile driving and at 
any time impact driving would occur after cessation of impact pile 
driving for a period of 30 minutes or longer;
    <bullet> In-water construction would occur during daylight over a 
12-hour workday to minimize the potential for PTS for species that may 
occur within the Level A harassment zones; and
    <bullet> When transiting to the site, marine mammal watches must be 
conducted by crew or those navigating the vessel. When in the Project 
Area, if a whale is sighted in the path of a support vessel or within 
92 m (300 feet) from the vessel, NSF must reduce speed and must not 
engage the engines until the animals are clear of the area. If a whale 
is sighted farther than 92 m (300 feet) from the vessel, NSF must 
maintain a distance of 92 m (300 feet) or greater between the whale and 
the vessel and reduce speed to 10 knots or less. Vessels must not be 
operated in such a way as to separate members of a group of whales from 
other members of the group. A group is defined as being three or more 
whales observed within a 500 m area and displaying behaviors of 
directed or coordinated activity (e.g., group feeding).

                           Table 21--Shutdown and Harassment Zones (meters) for Non-Simultaneous Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Minimum shutdown zone
                                                         --------------------------------------------------------------------------------     Level B
               Pile size, type, and method                                   Cetaceans                               Pinnipeds              harassment
                                                         --------------------------------------------------------------------------------    zone (m)
                                                                LF              MF              HF              PW              OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock, 36-in Dia. Pile Installation, 20' Socket Depth--1            1,900              70           2,255           1,015              50          11,659
 pile/day (DTH).........................................
Dock Abutment, 36-in Dia. Pile Installation, 30' Socket            2,500              90           2,955           1,330
 Depth--1 pile/day (DTH)................................
RHIB Fender Piles, 24-in Dia. Pile Installation, 20'                 410              15             485             220
 Socket--1 pile/day.....................................
24-in Dia. Template Piles, 10' Socket Depth--2 piles/day
24-in Dia. Wave Attenuator Piles, 20' Socket Depth--1
 pile/day...............................................
Retaining Wall HP Pile inserted in Drilled 24-in Dia.
 Sockets, 20' Socket Depth--1 pile/day..................
Removal of 24-in Dia. Template Piles--16 piles..........              55              10              75              35                          10,000
Removal of Sheet Piles..................................              25                              35              15                           4,642
Rock Chipping/Floor Preparation.........................             405              50             720             205                             123

[[Page 46222]]

 
Anode Installation......................................              10              10              10              10                             200
--------------------------------------------------------------------------------------------------------------------------------------------------------


                             Table 22--Shutdown and Harassment Zones (meters) for Simultaneous Pile Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Minimum shutdown zone
                                                         --------------------------------------------------------------------------------     Level B
                 Daily activity scenario                                     Cetaceans                               Pinnipeds              harassment
                                                         --------------------------------------------------------------------------------    zone (m)
                                                                LF              MF              HF              PW              OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock, 36-in Dia. Pile Installation, 20' Socket Depth--2            3,500             110           3,580           1,610              50          18,478
 pile/day...............................................
Dock Abutment, 36-in Dia. Pile Installation, 30' Socket                              125           4,150           1,865
 Depth and 36-in Dia. Pile 20' Socket Depth.............
RHIB Fender Piles, 24-in Dia. Pile Installation, 20'                 650              25             770             350
 Socket--2 pile/day.....................................
24-in Dia. Template Piles, 10' Socket Depth--4 piles/day
24-in Dia. Wave Attenuator Piles, 20' Socket Depth--2
 pile/day...............................................
Retaining Wall--HP Pile inserted in Drilled 24-in Dia.
 Sockets, 20' Socket Depth--2 piles/day.................
Dock, 36-in Dia. Pile Installation, 20' Socket Depth--1            2,050              75           2,400           1,080
 pile/day and Wave Attenuator, 24-in Dia. Pile
 Installation, 20' Socket--1 pile/day...................
Dock 36-in Dia. Pile Installation 30' Socket Depth and             2,900             105           3,500           1,545
 24-in Dia. Pile Installation 20' Socket Depth..........
36-in Dock 20' socket x 2 Dock Abutment.................              45              10              65              30                          34,146
RHIB Fender Piles 24-in x 2.............................              20                              30              10                          15,849
24-in template 10' socket x 4...........................
24-in wave attenuator piles-10' socket x 2..............              35                              50
24-in wave attenuator piles-20' socket x 2..............              35                              50
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed Project 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:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density).
    <bullet> Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas).
    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors.
    <bullet> How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks.

[[Page 46223]]

    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat).
    <bullet> Mitigation and monitoring effectiveness.

Visual Monitoring

    One NMFS-approved, formally trained PSO with prior experience 
performing the duties of a PSO during construction activities would 
serve as team leader, supported by three PSOs trained on site or 
through available online training programs compliant with NMFS 
standards. PSOs must be independent (i.e., not construction personnel) 
and have no other assigned tasks during monitoring periods. Prior to 
initiation of construction, PSOs would complete a training/refresher 
session on marine mammal monitoring, to be conducted shortly before the 
anticipated start of the open water season construction activities.
    Primary objectives of the training session include:
    <bullet> Review of the mitigation, monitoring, and reporting 
requirements provided in the application and IHA, including any 
modifications specified by NMFS in the authorization;
    <bullet> Review of marine mammal sighting, identification, and 
distance estimation methods;
    <bullet> Review of operation of specialized equipment (bigeye 
binoculars, GPS); and
    <bullet> Review of, and classroom practice with, data recording and 
data entry systems, including procedures for recording data on marine 
mammal sightings, monitoring operations, environmental conditions, and 
entry error control.
    PSOs must have the following additional qualifications:
    <bullet> Ability to conduct field observations and collect data 
according to assigned protocols;
    <bullet> Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
    <bullet> Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    <bullet> Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
    <bullet> Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Two PSOs must be on duty during all in-water construction 
activities and must record all observations of marine mammals 
regardless of distance from the pile being driven or covered activity. 
PSOs shall document any behavioral reactions in concert with distance 
from piles being driven or removed. PSOs are limited to monitoring no 
more than 4 hours per shift with sufficient breaks and no more than 12 
hours per day to minimize fatigue.
    The placement of PSOs during all pile driving and removal and 
drilling activities will ensure that the entire shutdown zones are 
visible during pile installation. Should environmental conditions 
deteriorate such that marine mammals within the entire shutdown zone 
will not be visible (e.g., fog, heavy rain), pile driving and removal 
must be delayed until the PSO is confident marine mammals within the 
shutdown zone could be detected. The primary monitoring location 
currently proposed by NSF would be on the roof platform of the Garage 
Warehouse Recreation (GWR) building (approximately 20 meters above sea 
level) to provide visual coverage of the Level A shutdown zones. NMFS 
agrees that the GWR building is an appropriate monitoring location. The 
primary PSO can monitor the Project Area generally south-southeast 
while the second PSO can monitor the area generally west-southwest that 
may be ensonified. With reticle binoculars the distance potentially 
visible by a 1.8-m tall PSO from this point would be about 4,360 m. 
Mounted big eye binoculars would be provided to PSOs to better cover 
the Level A harassment zone. NSF believes this location and is adequate 
to fully monitor the Level A harassment and shutdown zones, however, we 
note that sea state, glare, observer expertise, and other factors can 
affect the ability of PSOs to see and identify marine mammals to 
hearing group at such large distances, even if those distances are 
theoretically observable. Local researchers have reported that very 
little of some level B harassment zones will be visible (Ari 
Friedlander, personal communication).
    Palmer Station normally has 2.8 meter RHIBs, 2 4.8 m RHIBs, and a 
number of smaller boats that are normally available and used on a daily 
basis in areas within 2-3 miles of the station (Ari Friedlander, 
personal communication). NSF has stated that PSOs in boats that would 
monitor the outer part of the Level A or Level B harassment zones are 
not practicable because the remote location of the Project Area 
presents both safety and logistical challenges. Given the comparatively 
limited information regarding the species in this area and the likely 
impacts of construction activities on the species in this area, NMFS is 
specifically requesting public comment on the proposed monitoring and 
mitigation requirements.

Reporting

    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities, or 60 days prior to a requested date of issuance of any 
future IHAs for projects at the same location, whichever comes first. 
The report will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the report must include:
    <bullet> Dates and times (begin and end) of all marine mammal 
monitoring;
    <bullet> Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact or cutting) and the total 
equipment duration for cutting for each pile or total number of strikes 
for each pile (impact driving);
    <bullet> PSO locations during marine mammal monitoring;
    <bullet> Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
    <bullet> Upon observation of a marine mammal, the following 
information: Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting; Time of sighting; Identification of the 
animal(s) (e.g., genus/species, lowest possible taxonomic level, or 
unidentified), PSO confidence in identification, and the composition of 
the group if there is a mix of species; Distance and bearing of each 
marine mammal observed relative to the pile being driven for each 
sighting (if pile driving was occurring at time of sighting); Estimated 
number of animals (min/max/best estimate); Estimated number of animals 
by cohort (adults, juveniles, neonates, group composition, etc.); 
Animal's closest point of approach and estimated time spent within the 
harassment zone; Description of any

[[Page 46224]]

marine mammal behavioral observations (e.g., observed behaviors such as 
feeding or traveling), including an assessment of behavioral responses 
thought to have resulted from the activity (e.g., no response or 
changes in behavioral state such as ceasing feeding, changing 
direction, flushing, or breaching);
    <bullet> Number of marine mammals detected within the harassment 
zones, by species; and
    <bullet> Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    If no comments are received from NMFS within 30 days, the draft 
final report will constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the IHA-holder must 
immediately cease the specified activities and report the incident to 
the Office of Protected Resources (<a href="/cdn-cgi/l/email-protection#b0e0e29ef9e4e09efddfded9c4dfc2d9ded7e2d5c0dfc2c4c3f0dedfd1d19ed7dfc6"><span class="__cf_email__" data-cfemail="7525275b3c21255b381a1b1c011a071c1b122710051a070106351b1a14145b121a03">[email protected]</span></a>), 
NMFS as soon as feasible. If the death or injury was clearly caused by 
the specified activity, NSF must immediately cease the specified 
activities until NMFS is able to review the circumstances of the 
incident and determine what, if any, additional measures are 
appropriate to ensure compliance with the terms of the IHA. The IHA-
holder must not resume their activities until notified by NMFS. The 
report must include the following information:
    <bullet> Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    <bullet> Species identification (if known) or description of the 
animal(s) involved;
    <bullet> Condition of the animal(s) (including carcass condition if 
the animal is dead);
    <bullet> Observed behaviors of the animal(s), if alive;
    <bullet> If available, photographs or video footage of the 
animal(s); and
    <bullet> General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any 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).
    DTH pile installation, vibratory pile removal, limited impact pile 
driving for proofing, rock chipping and use of a hydrogrinder have the 
potential to disturb or displace marine mammals. Specifically, the 
project activities may result in take, in the form of Level A and Level 
B harassment from underwater sounds generated from pile driving 
activities. Potential takes could occur if individuals are present in 
the ensonified zone when these activities are underway.
    The takes from Level A and Level B harassment would be due to 
potential PTS, TTS and behavioral disturbance. Even absent mitigation, 
no mortality or serious injury is anticipated given the nature of the 
activity and construction method. The potential for harassment would be 
further minimized through the implementation of the planned mitigation 
measures (see Proposed Mitigation section).
    Effects on individual animals that are taken by Level B harassment, 
on the basis of reports in the literature as well as monitoring from 
other similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring) (e.g., Thorson and Reyff 
2006; HDR Inc. 2012; Lerma 2014; ABR 2016). Most likely, individuals 
will simply move away from the sound source and be temporarily 
displaced from the areas of pile installation, although even this 
reaction has been observed primarily only in association with impact 
pile driving. If sound produced by project activities is sufficiently 
disturbing, animals are likely to simply avoid the area while the 
activity is occurring. While DTH pile installation associated with the 
proposed project may produce sound at distances of many kilometers from 
the project site, we expect that animals annoyed by project sound would 
simply avoid the area and use more-preferred habitats. Furthermore, 
during any impact driving, implementation of soft start procedures will 
be required and monitoring of established shutdown zones will be 
required for all pile installation and removal activities, 
significantly reducing the possibility of injury. Use of impact driving 
will be limited to proofing of piles after they have been set in place. 
Given sufficient notice through use of soft start (for impact driving), 
marine mammals are expected to move away from an irritating sound 
source prior to it becoming potentially injurious. This sort of low-
level localized displacement, in the absence of any specific known 
biologically important areas, would not be expected to impact the 
reproduction or survival of any individuals.
    In addition to the expected effects resulting from authorized Level 
B harassment, we anticipate that Antarctic minke whales, fin whales, 
and humpback whales may sustain some limited Level A harassment in the 
form of auditory injury due to large PTS zones for LF cetaceans. We are 
also proposing to authorize take by Level A harassment of Antarctic fur 
seals, crabeater seals, leopard seals, Weddell seals, and Southern 
elephant seals since the Level A harassment zones are large relative to 
the ability to detect low profile, species that are common in the 
region. However, animals that experience PTS would likely be subjected 
to slight PTS, i.e., minor degradation of hearing capabilities within 
regions of hearing that align most completely with the frequency range 
of the energy produced by pile driving, i.e., the low-frequency region 
below 2 kHz, not severe hearing impairment or impairment in the regions 
of greatest hearing sensitivity. If hearing impairment occurs, it is 
most likely that the affected animal would lose a few decibels in its 
hearing sensitivity, which in most cases is not likely to

[[Page 46225]]

meaningfully affect its ability to forage and communicate with 
conspecifics.
    The project is also not expected to have significant adverse 
effects on affected marine mammals' habitats. The project activities 
would not modify existing marine mammal habitat for a significant 
amount of time. The activities may cause some fish to leave the area of 
disturbance, thus temporarily impacting marine mammals' foraging 
opportunities in a limited portion of the foraging range; but, because 
of the relatively small area of the habitat that may be affected, the 
impacts to marine mammal habitat are not expected to cause significant 
or long-term negative consequences for marine mammals.
    The nature of NSF's proposed construction activities precludes the 
likelihood of serious injury or mortality, even absent mitigation. For 
all species and stocks, take would occur within a limited area (Hero 
Inlet and nearby waters) that constitutes a small portion of the ranges 
for authorized species. Level A and Level B harassment will be reduced 
to the level of least practicable adverse impact through use of 
mitigation measures described herein. Further, the amount of take 
proposed to be authorized is extremely small when compared to stock 
abundance of authorized species.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
    <bullet> No mortality or serious injury is anticipated or 
authorized;
    <bullet> The relatively small number of Level A harassment 
exposures are anticipated to result only in slight PTS within the lower 
frequencies associated with pile driving;
    <bullet> The anticipated incidents of Level B harassment would 
consist of, at worst, temporary modifications in behavior that would 
not result in fitness impacts to individuals;
    <bullet> No adverse effects on affected marine mammals' habitat are 
anticipated;
    <bullet> No important habitat areas have been identified within the 
Project Area;
    <bullet> For all species, Hero Inlet and nearby waters represent 
very small and peripheral part of their ranges; and
    <bullet> The required mitigation measures (i.e., shutdown zones) 
are expected to be effective in reducing the effects of the specified 
activity.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The amount of take NMFS proposes to authorize is below one third of 
the estimated stock abundances for all 17 species. For all requested 
species, the proposed take of individuals is less than 6.4 percent of 
the abundance of the affected species or stock as shown in Table 20. 
This is likely a conservative estimate because it assumes all take are 
of different individual animals, which is likely not the case. Some 
individuals may return multiple times in a day, but PSOs would count 
them as separate takes if they cannot be individually identified.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species, in this case with the ESA Interagency 
Cooperation Division.
    NMFS is proposing to authorize take of blue whale, fin whale, sei 
whale, Southern right whale, and sperm whale, which are listed as 
endangered under the ESA.
    The Permit and Conservation Division has requested initiation of 
Section 7 consultation with the Interagency Cooperation Division for 
the issuance of this IHA. NMFS will conclude the ESA consultation prior 
to reaching a determination regarding the proposed issuance of the 
authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to NSF to conduct the Palmer Station Pier Replacement 
project at Anvers Island, Antarctica, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. A 
draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed Palmer 
Station Pier Replacement project. We also request at this time comment 
on the potential Renewal of this proposed IHA as described in the 
paragraph below. Please include with your comments any supporting data 
or literature citations to help inform decisions on the request for 
this IHA or a subsequent Renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, one-year 
Renewal IHA following notice to the public providing an additional 15 
days for public comments when (1) up to another year of identical or 
nearly identical, or nearly identical, activities as described in the 
Description of Proposed Activities section of this notice is planned or 
(2) the activities as described in the

[[Page 46226]]

Description of Proposed Activities section of this notice would not be 
completed by the time the IHA expires and a Renewal would allow for 
completion of the activities beyond that described in the Dates and 
Duration section of this notice, provided all of the following 
conditions are met:
    <bullet> A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that the 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA);
    <bullet> The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take); 
and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized; and
    Upon review of the request for Renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS determines 
that there are no more than minor changes in the activities, the 
mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: August 13, 2021.
Shannon Bettridge,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-17725 Filed 8-17-21; 8:45 am]
BILLING CODE 3510-22-P


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