Notice2021-17725
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Palmer Station Pier Replacement Project, Antarctica
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
August 18, 2021
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
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.
Full Text
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<title>Federal Register, Volume 86 Issue 157 (Wednesday, August 18, 2021)</title>
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[Federal Register Volume 86, Number 157 (Wednesday, August 18, 2021)]
[Notices]
[Pages 46199-46226]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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
<a href="http://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a> 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: <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>. 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)
(<a href="http://www.iucnredlist.org/">www.iucnredlist.org/</a>; 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
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
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 <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>.
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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