[Federal Register Volume 85, Number 42 (Tuesday, March 3, 2020)]
[Notices]
[Pages 12523-12540]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-04280]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XR099]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Ward Cove Cruise Ship Dock Project,
Juneau, Alaska
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 Power Systems & Supplies of
Alaska (PSSA) for authorization to take marine mammals incidental to
Ward Cove Cruise Ship Dock Project near Ketchikan, Alaska. Pursuant to
the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on
its proposal to issue an incidental harassment authorization (IHA) to
incidentally take marine mammals during the specified activities. NMFS
is also requesting comments on a possible one-year renewal that could
be issued under certain circumstances and if all requirements are met,
as described in Request for Public Comments at the end of this notice.
NMFS will consider public comments prior to making any final decision
on the issuance of the requested MMPA authorizations and agency
responses will be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than April 2,
2020.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Physical comments should be sent to
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments
should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Dwayne Meadows, Ph.D., Office of
Protected Resources, NMFS, (301) 427-8401. Electronic copies of the
application and supporting documents, as well as a list of the
references cited in this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth.
The definitions of all applicable MMPA statutory terms cited above
are included in the relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (incidental harassment authorizations with
no anticipated serious injury or mortality) of the Companion Manual for
NOAA Administrative Order 216-6A, which do not individually or
cumulatively have the potential for significant impacts on the quality
of the human environment and for which we have not identified any
extraordinary circumstances that would preclude this categorical
exclusion. Accordingly, NMFS has preliminarily determined that the
issuance of the proposed IHA qualifies to be categorically excluded
from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On December 30, 2019, NMFS received a request from PSSA for an IHA
to take marine mammals incidental to Ward Cove Cruise Ship Dock Project
near Ketchikan, Alaska. The application
[[Page 12524]]
was deemed adequate and complete on February 5, 2020. PSSA's request is
for take of harbor seals by Level B harassment and Level A harassment.
Neither PSSA nor NMFS expects serious injury or mortality to result
from this activity and, therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
The project consists of the construction of a cruise ship dock for
two cruise ships in Ward Cove, approximately eight kilometers (5 miles)
north of downtown Ketchikan, Alaska. PSSA would install a pile
supported 500-foot by 70-foot floating pontoon dock, mooring
structures, and shore-access transfer span and trestle. The project
includes the following in-water components: Driving one hundred and two
30-48 inch diameter steel pipe piles to support the structures and
removal of 48 of these piles (all 30-inch diameter) that are being used
solely as templates to guide installation of larger permanent piles. It
is expected to take no more than 105 days of in-water work. Pile
driving would be by vibratory pile driving until resistance is too
great and driving would switch to an impact hammer. Removal of
temporary piles would use vibratory methods only. Forty larger 36- and
48-inch piles would also be rock anchored into place using a down-the-
hole (DTH) drill.
The pile driving/removal or rock anchoring can result in take of
marine mammals from sound in the water which results in behavioral
harassment or auditory injury. The footprint of the project is
approximately 1.5 square miles around the project site.
Dates and Duration
The work for which take will be authorized began in February 2020.
In the time period before we authorize take the applicant has agreed
with us to shut down pile driving anytime marine mammals are seen in
the Level B Harassment Zone of the project area (see below). PSSA
believes they are able to avoid unauthorized take through the use of
mitigation and monitoring measures agreed described in their
application. Because we do not know exactly when an IHA will be issued,
nor exactly how much of the project activities will be complete when an
authorization is in place, we may lower the take authorization at final
issuance of this IHA. Under an existing permit issued by the Army Corps
of Engineers and an Endangered Species Act (ESA) Section 7 Letter of
Concurrence issued by NMFS, impact pile driving will cease by June 30
to protect endangered salmon and vibratory pile driving and rock
anchoring will cease by July 31 to protect other ESA listed species.
PSSA has proposed the daily construction window for pile removal and
driving would begin no sooner than 30 minutes after sunrise and would
end 30 minutes prior to sunset to allow for marine mammal monitoring.
Specific Geographic Region
The project site is located in Ward Cove north of Ketchikan, Alaska
(Figure 1). Ward Cove is a small estuary with an area of approximately
1 square kilometer (0.4 square mile) located off the western coast of
Revillagigedo Island and on the North Shore of Tongass Narrows. The
cove is approximately 1.6 kilometers long (1 mile) and 0.8 kilometers
(0.5 mile) wide with depths to 60 meters (200 feet) (EPA 2015, NOAA
2016). The cove has experienced significant industrialization as it was
the former site of a pulp mill, sawmill, and fish processing plant.
Effluent and materials from these former industries polluted the cove.
The bottom substrate is organic-rich sediments areas overlaid with
either sandy material that has been thinly placed (``capped;'' 15-23
inches thick) or sandy material that has been mounded (approximately
1.45 meters thick) as a remediation requirement for the earlier
pollution. Deep water areas have deep organic sediments with no sandy
overlay. Some areas have a high density of old sunken logs from the
sawmill operations (Exponent 2000). Silt curtains will be used around
pile driving operations and sediments captured as drill cutting
discharge will be removed (see below) and will trap most suspended
sediments and prevent dispersal into the wider environment.
Sound from project activities is expected to also move into Tongass
Narrows. Tongass Narrows is a U-shaped glacier-carved fjord that varies
between 300 meters (0.2 mile) to 2.4 kilometers (1.5 miles) wide and 15
meters (49 feet) to 55 meters (180 feet) deep (ADEC 2017, NOAA 2016).
Tongass Narrows is known for strong tidal currents and unusually large
tidal ranges of 8 meters (feet) or more (Pentec 2001). The Narrows are
characterized by steep bedrock or coarse gravel-cobble-boulder
shoreline.
Detailed Description of Specific Activity
The proposed project includes the installation of steel piles to
support a new 500-foot by 70-foot floating pontoon dock, mooring
structures, and shore-access transfer span and trestle. The project
will:
Install 48 temporary 30-inch diameter steel piles as
templates to guide proper installation of permanent piles (these
temporary piles would be removed prior to project completion);
Install 14 permanent 30-inch diameter piles, 20 permanent
36-inch diameter piles, and 20 permanent 48-inch diameter piles to
support a new 500-foot x 70-foot floating pontoon dock, mooring
structures, and shore-access transfer span and trestle for a total of
54 piles;
Install dock components such as bull rail, floating
fenders, mooring cleats, vehicle driveway, curb, passenger walkway,
hand rail, and mast lights.
The temporary, 30-inch diameter piles serving as a template would
be installed and removed using a vibratory hammer. The 14 permanent 30-
inch trestle piles will be installed through sand and gravel with a
vibratory hammer and impact hammer. The 54 permanent 36-inch and 48-
inch diameter piles will be driven through sand and gravel with a
vibratory hammer and then impact driven into bedrock. After being
impacted, these piles will be rock anchored. To rock anchor the pile, a
DTH hammer with a 33-inch-diameter bit will be used to drill a shaft
into the bedrock. The drill bit will be removed, and the shaft will be
filled with vertical reinforcement (a rebar cage) in concrete to secure
the pile. The depth of the shaft is to be determined by a geotechnical
engineer prior to construction. During anchor drilling the pile will
not be touched by the drill, and no steel-on-steel hammer noise will be
generated. As much as possible, the hammer will be operated at a
reduced energy setting. The contractor will use high-density
polyethylene or ultra-high-molecular-weight polyethylene softening
material (pile caps) on all templates to eliminate steel on steel noise
generation.
In-water construction of the cruise ship dock will begin with
installation of the trestle. Once the trestle is constructed, dolphins
will be constructed. Trestle and dolphin construction will follow this
sequence:
(1) Vibrate 32 temporary 30-inch-diameter piles for the trestle,
and 16 temporary 30-inch diameter piles for the dolphins, a minimum of
10 feet into overburden to create a template to guide installation of
permanent piles;
(2) Weld a template frame around the temporary piles;
(3) Within the template frame, vibrate and impact 14 permanent 30-
inch diameter piles into place for the trestle; or vibrate, impact, and
rock anchor 20 permanent 36-inch and 20 48-inch
[[Page 12525]]
diameter piles into place for the dolphins;
(4) Remove the template frame and temporary piles; and
(5) Perform this sequence at the seven trestle bent locations,
working farther from the shoreline each sequence. Once the trestle is
completed perform this sequence at the eight dolphin locations.
After all piles are installed, construction will proceed with
installation of the floating dock, transfer span, trestle, mechanical
systems, and other above-water components like the vehicle driveway,
passenger walkway, and mast lights. Two barges and two small boats will
be used to facilitate the construction, transport and stage materials,
and support protected species monitoring. Additional standard barges,
tug boats, or clamshell equipment will be used to place or remove
material (including submerged logs) and position piles on the substrate
via a crane.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TN03MR20.000
BILLING CODE 3510-22-C
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (https://www.fisheries.noaa.gov/find-species).
Table 1 lists all species with expected potential for occurrence in
the project area near Ketchikan, Alaska and summarizes information
related to the population or stock, including regulatory status under
the MMPA and ESA and potential biological removal (PBR), where known.
For taxonomy, we follow Committee on Taxonomy (2019). PBR is defined by
the MMPA as the maximum number of animals, not including natural
mortalities, that may be removed from a marine mammal stock while
allowing that stock to reach or maintain its optimum sustainable
population (as described in NMFS's SARs). While no mortality is
anticipated or authorized here, PBR and annual serious injury and
mortality from anthropogenic sources are included here as gross
indicators of the status of the species and other threats.
Marine mammal abundance estimates presented in this document
represent
[[Page 12526]]
the total number of individuals that make up a given stock or the total
number estimated within a particular study or survey area. NMFS's stock
abundance estimates for most species represent the total estimate of
individuals within the geographic area, if known, that comprises that
stock. For some species, this geographic area may extend beyond U.S.
waters. All managed stocks in this region are assessed in NMFS's U.S.
Alaska SARs (e.g., Muto et al. 2019). All values presented in Table 1
are the most recent available at the time of publication and are
available in the 2019 draft SARs (Muto et al., 2019).
Table 1--Marine Mammals That Could Occur in the Proposed Project Area
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Stock abundance Nbest,
ESA/MMPA status; (CV, Nmin, most recent Annual M/
Common name Scientific name MMPA stock Strategic (Y/N) abundance survey) \2\ PBR SI \3\
\1\
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Eschrichtiidae:
Gray Whale...................... Eschrichtius robustus.. Eastern North Pacific.. -, -, N 26,960 (0.05, 25,849, 801 138
2016).
Family Balaenidae:
Humpback whale.................. Megaptera novaeangliae. Central North Pacific.. E, D,Y 10,103 (0.3; 7,891; 83 25
2006).
Minke whale......................... Balaenoptera Alaska................. -, N N.A................... N.A. N.A.
acutorostrata.
Fin whale........................... Balaenoptera physalus.. Northeast Pacific...... E, D, Y N.A................... 5.1 0.4
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Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer whale.................... Orcinus orca........... Alaska Resident........ -, N 2,347 (N.A.; 2,347; 24 1
2012).
West Coast Transient... -, N 243 (N.A, 243, 2009).. 2.4 0
Northern Resident...... -, N 302 (N.A.; 302, 2018). 2.2 0.2
Pacific white-sided dolphin..... Lagenorhynchus North Pacific.......... -,-; N 26,880 (N.A.; N.A.; N.A. 0
obliquidens. 1990).
Family Phocoenidae:
Harbor porpoise................. Phocoena phocoena...... Southeast Alaska....... -, Y 975 (0.10; 896; 2012). 8.95 34
Dall's porpoise................. Phocoenoides dalli..... Alaska................. -, N N.A................... N.A. 38
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Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
sea lions):
Steller sea lion................ Eumetopias jubatus..... Eastern U.S............ -,-, N 43,201 (N.A.; 43,201; 2,592 113
2017).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina Clarence Strait........ -, N 27,659 (N.A.; 24,854; 746 40
richardii. 2015).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
All 10 species that could potentially occur in the proposed survey
areas are included in Table 1. However, the temporal and/or spatial
occurrence and mitigation measures implemented for seven species (all
in Table 1 except harbor seals, Dall's porpoise, and harbor porpoise)
is such that take is not expected to occur, and they are not discussed
further beyond the explanation provided here. These seven species are
not expected to have take occur because the applicant will shut down
pile driving and rock anchoring activities if these species are
observed within the Level B harassment zone defined below.
Additionally, minke whale, fin whale, gray whale, Pacific white-sided
dolphins and killer whales are rare in the area. The applicant only
requested take of harbor seals (see above), but we believe the cryptic
nature, small size, and dive duration of Dall's porpoise and harbor
porpoise make it possible that these two species could also be taken.
Therefore we propose to authorize take for these species (see below)
and PSSA concurred.
In addition, the northern sea otter may be found in the project
vicinity. However, that species is managed by the U.S. Fish and
Wildlife Service and is not considered further in this document.
Harbor Seal
Harbor seals (Phoca vitulina) inhabit coastal and estuarine waters
off Alaska. They haul out on rocks, reefs, beaches, and drifting
glacial ice. They are opportunistic feeders and often adjust their
distribution to take advantage of locally and seasonally abundant prey
(Womble et al., 2009, Allen and Angliss, 2015).
Harbor seals occurring in the project area belong to the Clarence
Strait stock. Distribution of the Clarence Strait stock ranges from the
east coast of Prince of Wales Island from Cape Chacon north through
Clarence Strait to Point Baker and along the east coast of Mitkof and
Kupreanof Islands north to Bay Point, including Ernest Sound, Behm
Canal, and Pearse Canal (Muto et al. 2019). In the project area, they
tend to be more abundant during spring, summer and fall months when
salmon are present in Ward Creek. Anecdotal evidence indicates that
harbor seals typically occur in groups of 1-3 animals in Ward Cove
(Spokely 2019). They were not observed in Tongass Narrows during a
combined 63.5 hours of marine mammal monitoring that took place in 2001
and 2016 (OSSA 2001, Turnagain 2016). There are no known harbor seal
haulouts within the project area.
[[Page 12527]]
According to the list of harbor seal haulout locations, the closest
listed haulouts are located off the tip of Gravina Island,
approximately eight kilometers (five miles) northwest of Ward Cove
(AFSC 2018).
Dall's Porpoise
Dall's porpoises (Phocoenoides dalli) are found throughout the
North Pacific, from southern Japan to southern California north to the
Bering Sea. All Dall's porpoises in Alaska are members of the Alaska
stock. This species can be found in offshore, inshore, and nearshore
habitat.
Jefferson et al. (2019) presents historical survey data showing few
sightings in the Ketchikan area. The mean group size in Southeast
Alaska is estimated at approximately three individuals (Dahlheim et al.
2009, Jefferson et al. 2019), although Freitag (2017, as cited in 83 FR
37473) suggested group sizes near Ketchikan range from 10 to 15
individuals. Anecdotal reports suggest that Dall's porpoises are found
northwest of Ketchikan near the Guard Islands, where waters are deeper,
as well as in deeper waters to the southeast of Tongass Narrows. This
species has a tendency to bow-ride with vessels and may occur in the
action area incidentally a few times per year.
Harbor Porpoise
In the eastern North Pacific Ocean, the harbor porpoise (Phocoena
phocoena) ranges from Point Barrow, along the Alaska coast, and down
the west coast of North America to Point Conception, California. The
Southeast Alaska stock ranges from Cape Suckling to the Canadian border
(Muto et al. 2019). Harbor porpoises frequent primarily coastal waters
in Southeast Alaska (Dahlheim et al. 2009) and occur most frequently in
waters less than 100 meters (328 feet) deep (Dahlheim et al. 2015).
They are not attracted to areas with elevated levels of vessel activity
and noise such as Tongass Narrows.
Studies of harbor porpoises reported no evidence of seasonal
changes in distribution for the inland waters of Southeast Alaska
(Dahlheim et al. 2009). Their small overall size, lack of a visible
blow, low dorsal fins and overall low profile, and short surfacing time
make them difficult to spot (Dahlheim et al. 2015). Ketchikan area
densities are expected to be low. This is supported by anecdotal
estimates. Anecdotal reports (see IHA Application) specific to Tongass
Narrows indicate that harbor porpoises are rarely observed in the
action area. Harbor porpoises are expected to be present in the action
area only a few times per year.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 2.
Table 2--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range*
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Harbor seals are in the phocid group and Dall's and harbor porpoises
are classified as high-frequency cetaceans.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take by Incidental Harassment section
later in this document includes a quantitative analysis of the number
of individuals that are expected to be taken by this activity. The
Negligible Impact Analysis and Determination section considers the
content of this section, the Estimated Take by Incidental Harassment
section, and the Proposed Mitigation section, to draw conclusions
regarding the likely impacts of these activities on the reproductive
success or survivorship of individuals and how those impacts on
individuals are likely to impact marine mammal species or stocks.
[[Page 12528]]
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (ANSI 1994, 1995). The sound level of an area
is defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., waves, wind,
precipitation, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
In-water construction activities associated with the project would
include impact pile driving, vibratory pile driving, and rock
anchoring. The sounds produced by these activities fall into one of two
general sound types: impulsive and non-impulsive. Impulsive sounds
(e.g., explosions, gunshots, sonic booms, impact pile driving) are
typically transient, brief (less than 1 second), broadband, and consist
of high peak sound pressure with rapid rise time and rapid decay (ANSI,
1986; NIOSH, 1998; ANSI, 2005; NMFS, 2018). Non-impulsive sounds (e.g.,
machinery operations such as drilling or dredging, vibratory pile
driving, and active sonar systems) can be broadband, narrowband or
tonal, brief or prolonged (continuous or intermittent), and typically
do not have the high peak sound pressure with raid rise/decay time that
impulsive sounds do (ANSI 1995; NIOSH 1998; NMFS 2018). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward 1997 in Southall et al., 2007).
Two types of pile hammers would be used on this project: Impact and
vibratory. Impact hammers operate by repeatedly dropping a heavy piston
onto a pile to drive the pile into the substrate. Sound generated by
impact hammers is characterized by rapid rise times and high peak
levels, a potentially injurious combination (Hastings and Popper,
2005). Vibratory hammers install piles by vibrating them and allowing
the weight of the hammer to push them into the sediment. Vibratory
hammers produce significantly less sound than impact hammers. Peak
Sound pressure Levels (SPLs) may be 180 dB or greater, but are
generally 10 to 20 dB lower than SPLs generated during impact pile
driving of the same-sized pile (Oestman et al., 2009). Rise time is
slower, reducing the probability and severity of injury, and sound
energy is distributed over a greater amount of time (Nedwell and
Edwards, 2002; Carlson et al., 2005).
Rock anchoring would be conducted using a DTH drill inserted
through the hollow steel piles. A DTH drill is a drill bit that drills
through the bedrock using a pulse mechanism that functions at the
bottom of the hole. This pulsing bit breaks up rock to allow removal of
debris and insertion of the pile. The head extends so that the drilling
takes place below the pile. The pulsing sounds produced by the DTH
drilling method are considered continuous as the noise from the
drilling component is expected to be dominant. In addition, the method
in this case likely increases sound attenuation because the noise is
primarily contained within the steel pile and below ground as opposed
to impact hammer driving methods which occur at the top of the pile and
introduce sound into the water column to a greater degree. See our
detailed discussion of this sound source in the notice of issuance of
an IHA for Ferry Berth Improvements in Tongass Narrows, Alaska https://www.govinfo.gov/content/pkg/FR-2020-01-07/pdf/2020-00038.pdf.
The likely or possible impacts of PSSA's proposed activity on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, any impacts to marine
mammals are expected to primarily be acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
installation and removal and drilling.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal and rock anchoring is the
primary means by which marine mammals may be harassed from PSSA's
specified activity. In general, animals exposed to natural or
anthropogenic sound may experience physical and psychological effects,
ranging in magnitude from none to severe (Southall et al., 2007).
Generally, exposure to pile driving and drilling noise has the
potential to result in auditory threshold shifts and behavioral
reactions (e.g., avoidance, temporary cessation of foraging and
vocalizing, changes in dive behavior). Exposure to anthropogenic noise
can also lead to non-observable physiological responses such an
increase in stress hormones. Additional noise in a marine mammal's
habitat can mask acoustic cues used by marine mammals to carry out
daily functions such as communication and predator and prey detection.
The effects of pile driving and drilling noise on marine mammals are
dependent on several factors, including, but not limited to, sound type
(e.g., impulsive vs. non-impulsive), the species, age and sex class
(e.g., adult male vs. mom with calf), duration of exposure, the
distance between the pile and the animal, received levels, behavior at
time of exposure, and previous history with exposure (Wartzok et al.,
2004; Southall et al., 2007). Here we discuss physical auditory effects
(threshold shifts) followed by behavioral effects and potential impacts
on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (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
[[Page 12529]]
hearing and vocalization frequency range of the exposed species
relative to the signal's frequency spectrum (i.e., how animal uses
sound within the frequency band of the signal; e.g., Kastelein et al.,
2014), and the overlap between the animal and the source (e.g.,
spatial, temporal, and spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). Available data from
humans and other terrestrial mammals indicate that a 40 dB threshold
shift approximates PTS onset (see Ward et al., 1958, 1959; Ward, 1960;
Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson and
Hu, 2008). PTS levels for marine mammals are estimates, with the
exception of a single study unintentionally inducing PTS in a harbor
seal (Kastak et al., 2008), there are no empirical data measuring PTS
in marine mammals, largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels
inducing PTS are not typically pursued or authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--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
Southall et al., 2007), 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, 2002). As described in Finneran
(2016), marine mammal studies have shown the amount of TTS increases
with cumulative sound exposure level (SELcum) in an
accelerating fashion: At low exposures with lower SELcum,
the amount of TTS is typically small and the growth curves have shallow
slopes. At exposures with higher SELcum, the growth curves
become steeper and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in 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.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis)) and five species of pinnipeds exposed to a limited
number of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran, 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran, 2015). The potential for TTS from impact pile driving
exists. After exposure to playbacks of impact pile driving sounds (rate
2760 strikes/hour) in captivity, mean TTS increased from 0 dB after 15
minute exposure to 5 dB after 360 minute exposure; recovery occurred
within 60 minutes (Kastelein et al., 2016). Additionally, the existing
marine mammal TTS data come from a limited number of individuals within
these species. No data are available on noise-induced hearing loss for
mysticetes. For summaries of data on TTS in marine mammals or for
further discussion of TTS onset thresholds, please see Southall et al.
(2007), Finneran and Jenkins (2012), Finneran (2015), and Table 5 in
NMFS (2018).
Installing piles requires a combination of impact pile driving,
vibratory pile driving, and DTH drilling. For the project, these
activities would not occur at the same time and there would likely be
pauses in activities producing the sound during each day. Given these
pauses and that many marine mammals are likely moving through the
action area and not remaining for extended periods of time, the
potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
removal and drilling also has the potential to behaviorally disturb
marine mammals. Available studies show wide variation in response to
underwater sound; therefore, it is difficult to predict specifically
how any given sound in a particular instance might affect marine
mammals perceiving the signal. If a marine mammal does react briefly to
an underwater sound by changing its behavior or moving a small
distance, the impacts of the change are unlikely to be significant to
the individual, let alone the stock or population. However, if a sound
source displaces marine mammals from an important feeding or breeding
area for a prolonged period, impacts on individuals and populations
could be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007;
NRC, 2005).
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 and C of Southall et
al. (2007) for a review of studies involving marine mammal behavioral
responses to sound.
[[Page 12530]]
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.
In 2016, the Alaska Department of Transportation and Public
Facilities (ADOT&PF) documented observations of marine mammals during
construction activities (i.e., pile driving and DTH drilling) at the
Kodiak Ferry Dock (see 80 FR 60636, October 7, 2015). In the marine
mammal monitoring report for that project (ABR 2016), 1,281 Steller sea
lions were observed within the Level B disturbance zone during pile
driving or drilling (i.e., documented as Level B harassment take). Of
these, 19 individuals demonstrated an alert behavior, 7 were fleeing,
and 19 swam away from the project site. All other animals (98 percent)
were engaged in activities such as milling, foraging, or fighting and
did not change their behavior. In addition, two sea lions approached
within 20 meters of active vibratory pile driving activities. Three
harbor seals were observed within the disturbance zone during pile
driving activities; none of them displayed disturbance behaviors.
Fifteen killer whales and three harbor porpoise were also observed
within the Level B harassment zone during pile driving. The killer
whales were travelling or milling while all harbor porpoises were
travelling. No signs of disturbance were noted for either of these
species. Given the similarities in activities and habitat and the fact
the same species are involved, we expect similar behavioral responses
of marine mammals to PSSA's specified activity. That is, disturbance,
if any, is likely to be temporary and localized (e.g., small area
movements). Monitoring reports from other recent pile driving and DTH
drilling projects in Alaska have observed similar behaviors (for
example, the Biorka Island Dock Replacement Project https://www.fisheries.noaa.gov/action/incidental-take-authorization-faa-biorka-island-dock-replacement-project-sitka-ak).
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. The
Ketchikan area contains active commercial shipping, cruise ship and
ferry operations, as well as numerous recreational and other commercial
vessels; therefore, background sound levels in the area are already
elevated.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and removal and DTH drilling that have the potential to cause
behavioral harassment, depending on their distance from pile driving
activities. Cetaceans are not expected to be exposed to airborne sounds
that would result in harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the acoustic criteria. We recognize that
pinnipeds in the water could be exposed to airborne sound that may
result in behavioral harassment when looking with their heads above
water. Most likely, airborne sound would cause behavioral responses
similar to those discussed above in relation to underwater sound. For
instance, anthropogenic sound could cause hauled-out pinnipeds to
exhibit changes in their normal behavior, such as reduction in
vocalizations, or cause them to temporarily abandon the area and move
further from the source. However, these animals would previously have
been `taken' because of exposure to underwater sound above the
behavioral harassment thresholds, which are in all cases larger than
those associated with airborne sound. Thus, the behavioral harassment
of these animals is already accounted for in these estimates of
potential take. Moreover, there are no known haulout areas near the
project. Therefore, we do not believe that authorization of incidental
take resulting from airborne sound for pinnipeds is warranted, and
airborne sound is not discussed further here.
Marine Mammal Habitat Effects
PSSA's construction activities in Ward Cove could have localized,
temporary impacts on marine mammal habitat and their prey by increasing
in-water sound pressure levels and slightly decreasing water quality.
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 impact pile
driving, elevated levels of underwater noise would ensonify Ward Cove
and adjacent Tongass Narrows where both fishes and mammals occur and
could affect foraging success.
Construction activities are of short duration and would likely have
temporary impacts on marine mammal habitat through increases in
underwater and airborne sound.
In-water pile driving, pile removal, and drilling activities would
also cause short-term effects on water quality due to increased
turbidity. The use of silt curtains and the removal of sediments
captured as drill cutting discharge (see below) will trap most
suspended sediments and prevent dispersal into the wider environment.
Local strong currents are anticipated to disburse any additional
suspended sediments produced by project activities at moderate to rapid
rates depending on tidal stage. PSSA would employ other standard
construction best management practices (see section 11 in application),
[[Page 12531]]
thereby reducing any impacts. Therefore, the impact from increased
turbidity levels is expected to be discountable.
In-Water Construction Effects on Potential Foraging Habitat
The area likely impacted by the project is relatively small
compared to the available habitat (e.g., most of the impacted area is
limited to Ward Cove) and does not include any Biologically Important
Areas or other habitat of known importance. Pile installation/removal
and drilling may temporarily increase turbidity resulting from
suspended sediments. Any increases would be temporary, localized, and
minimal. PSSA must comply with state water quality standards during
these operations by using silt curtains and removing all sediments
captured as drill cutting discharge to upland disposal sites. In
general, turbidity associated with pile installation is localized to
about a 25-foot radius around the pile (Everitt et al., 1980). Any
pinnipeds would be transiting the area and could avoid localized areas
of turbidity. Therefore, the impact from increased turbidity levels is
expected to be discountable to marine mammals. Furthermore, pile
driving and removal at the project site would not obstruct movements or
migration of marine mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. 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. 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.
The duration of the construction activities is relatively short.
The construction window is for a maximum of 4-5 months. During each
day, construction activities would only occur during daylight hours.
Impacts to habitat and prey are expected to be minimal based on the
short duration of activities and small size of Ward Cove.
In-water Construction Effects on Potential Prey (Fish)--
Construction activities would produce continuous (i.e., vibratory pile
driving and DTH drilling) and pulsed (i.e. impact driving) sounds. Fish
react to sounds that are especially strong and/or intermittent low-
frequency sounds. Short duration, sharp sounds can cause overt or
subtle changes in fish behavior and local distribution. Hastings and
Popper (2005) identified several studies that suggest fish may relocate
to avoid certain areas of sound energy. Additional studies have
documented effects of pile driving on fish, although several are based
on studies in support of large, multiyear bridge construction projects
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Sound
pulses at received levels of 160 dB may cause subtle changes in fish
behavior. SPLs of 180 dB may cause noticeable changes in behavior
(Pearson et al., 1992; Skalski et al., 1992). SPLs of sufficient
strength have been known to cause injury to fish and fish mortality.
The most likely impact to fish from pile driving and drilling
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. There are times of known
seasonal marine mammal foraging in Tongass Narrows around fish
processing/hatchery infrastructure or when fish are congregating, but
the impacted areas of Tongass Narrows are a small portion of the total
foraging habitat available in the region. In general, impacts to marine
mammal prey species are expected to be minor and temporary due to the
short timeframe of the project and the small project footprint.
Construction activities, in the form of increased turbidity, have
the potential to adversely affect forage fish and juvenile salmonid
outmigratory routes in the project area. Both herring and salmon form a
significant prey base for Steller sea lions, herring is a primary prey
species of humpback whales, and both herring and salmon are components
of the diet of many other marine mammal species that occur in the
project area. Increased turbidity is expected to occur in the immediate
vicinity (on the order of 10 feet or less) of construction activities.
However, suspended sediments and particulates are expected to dissipate
quickly within a single tidal cycle. Given the limited area affected
and high tidal dilution rates any effects on forage fish and salmon are
expected to be minor or negligible. In addition, best management
practices would be in effect, which would limit the extent of turbidity
to the immediate project area. Finally, exposure to turbid waters from
construction activities is not expected to be different from the
current exposure; fish and marine mammals in the Tongass Narrows region
are routinely exposed to substantial levels of suspended sediment from
glacial sources.
In summary, given the short daily duration of sound associated with
individual pile driving and drilling events and the relatively small
areas being affected, pile driving and drilling activities associated
with the proposed action are not likely to have a permanent, adverse
effect on any fish habitat, or populations of fish species. Thus, we
conclude that impacts of the specified activity are not likely to have
more than short-term adverse effects on any prey habitat or populations
of prey species. Further, any impacts to marine mammal habitat are not
expected to result in significant or long-term consequences for
individual marine mammals, or to contribute to adverse impacts on their
populations.
Estimated Take
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 source (i.e., vibratory or impact pile driving or DTH
drilling) 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 for pinnipeds
because predicted auditory injury zones are larger and harbor seals are
the only animals routinely seen in Ward Cove. The proposed mitigation
and monitoring measures are expected to minimize the severity of the
taking to the extent practicable.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent
[[Page 12532]]
hearing impairment; (2) the area or volume of water that will be
ensonified above these levels in a day; (3) the density or occurrence
of marine mammals within these ensonified areas; and, (4) and the
number of days of activities. We note that while these basic factors
can contribute to a basic calculation to provide an initial prediction
of takes, additional information that can qualitatively inform take
estimates is also sometimes available (e.g., previous monitoring
results or average group size). Due to the lack of marine marine mammal
density, NMFS relied on local occurrence data and group size to
estimate take. Below, we describe the factors considered here in more
detail and present the proposed take estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed acoustic
thresholds that identify the received level of underwater sound above
which exposed marine mammals would be reasonably expected to be
behaviorally harassed (equated to Level B harassment) or to incur PTS
of some degree (equated to Level A harassment).
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 microPascal ([mu]Pa) (root mean square
(rms)) for continuous (e.g., vibratory pile-driving, drilling) and
above 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g.,
impact pile driving) or intermittent (e.g., scientific sonar) sources.
PSSA's proposed activity includes the use of continuous (vibratory
pile-driving, DTH drilling) and impulsive (impact pile-driving)
sources, and therefore the 120 and 160 dB re 1 [mu]Pa (rms) thresholds
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). PSSA's activity includes the use of
impulsive (impact pile-driving) and non-impulsive (vibratory pile
driving/removal and drilling) sources.
These thresholds are provided in Table 3. The references, analysis,
and methodology used in the development of the thresholds are described
in NMFS 2018 Technical Guidance, which may be accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds \*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW): (Underwater).... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW): (Underwater)... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., impact pile driving, vibratory
pile driving, vibratory pile removal, and DTH drilling).
Vibratory hammers produce constant sound when operating, and
produce vibrations that liquefy the sediment surrounding the pile,
allowing it to penetrate to the required seating depth. An impact
hammer would then generally be used to place the pile at its intended
depth through rock or harder substrates. The actual durations of each
installation method vary depending on the type and size of the pile. An
impact hammer is a steel device that works like a piston, producing a
series of independent strikes to drive the pile. Impact hammering
typically generates the loudest noise associated with pile
installation.
In order to calculate distances to the Level A harassment and Level
B harassment sound thresholds for piles of various sizes being used in
this project, NMFS used acoustic monitoring data
[[Page 12533]]
from other locations to develop source levels (see Table 4). Note that
piles of differing sizes have different sound source levels (SSLs).
Empirical data from recent ADOT&PF sound source verification (SSV)
studies at Ketchikan were used to estimate sound source levels for
vibratory and impact driving of 30-inch steel pipe piles and Kodiak for
drilling (Denes et al. 2016). Data from Ketchikan was used because of
its proximity to this proposed project in Tongass Narrows and Kodiak
drilling data was used as a proxy here because of its relative
proximity. Details are described below.
The source level for rock anchoring was derived from the above
mentioned ADOT&PF SSV study at Kodiak, Alaska. The reported median
source value for drilling was determined to be 166.2 dB rms for all
pile types (Denes et al. 2016, Table 72). See our detailed discussion
of this sound source in the notice of issuance of an IHA for Ferry
Berth Improvements in Tongass Narrows, Alaska https://www.govinfo.gov/content/pkg/FR-2020-01-07/pdf/2020-00038.pdf
Table 4--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Installation, Drilling, and Vibratory Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Method and pile type Sound source level at 10 meters Literature source
rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr
Vibratory Hammer..................... dB rms
30-inch steel piles.................. 161.9 Denes et al. 2016, Table 72.
36-inch steel piles.................. 168.2 Austin et al. 2016, Table 16.
48-inch steel piles.................. 168.2 Austin et al. 2016, Table 16.
Drilling Rock Anchors................ dB rms
All pile diameters............... 166.2 Denes et al. 2016, Table 72.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Hammer dB peak dB SS SEL
All pile diameters................... 212...................... 186.7.................... Austin et al. 2016, Tables 9, 16.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: It is assumed that noise levels during pile installation and removal are similar. Use of an impact hammer will be limited to 5-10 minutes per
pile, if necessary. It is assumed that drilling produces the same SSL for both pile diameters. SS SEL = single strike sound exposure level; dB peak =
peak sound level; rms = root mean square.
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 PSSA's proposed activity.
Using the practical spreading model, PSSA determined underwater
noise would fall below the behavioral effects threshold of 120 dB rms
for marine mammals at a maximum radial distance of 16,343 m for
vibratory pile driving the 36 and 48-inch diameter piles. This distance
determines the maximum Level B harassment zone for the project. Other
activities, including rock anchoring and impact pile driving, have
smaller Level B harassment zones. All Level B harassment isopleths are
reported in Table 5 below and visualized in Figure 6 and Table 5 in the
IHA application. It should be noted that based on the geography of Ward
Cove, Tongass Narrows and the surrounding islands, sound will not reach
the full distance of the Level B harassment isopleth. Generally, due to
interaction with land, only a thin slice of the possible area is
ensonified and the maximum distance before reaching land barriers is
3,645 m.
Table 5--Calculated Distances to Level B Harassment Isopleths During
Pile Installation and Removal
------------------------------------------------------------------------
Level B
Pile size isopleth
(m)
------------------------------------------------------------------------
Vibratory Pile Driving/Removal:
30-inch piles.............................................. 6,213
36-inch piles.............................................. 16,343
48-inch piles.............................................. 16,343
Impact Pile Driving:
30-inch piles.............................................. 3,744
36-inch piles.............................................. 3,744
48-inch piles.............................................. 3,744
Rock Anchoring:
136-inch piles............................................. 12,023
148-inch piles............................................. 12,023
------------------------------------------------------------------------
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 take by Level A harassment. 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
impact/vibratory pile driving or drilling, NMFS User Spreadsheet
predicts the closest distance at which, if a marine mammal remained at
that distance the whole duration of the activity, it would not incur
PTS.
Inputs used in the User Spreadsheet (Table 6), and the resulting
isopleths are reported below (Table 7). Level A
[[Page 12534]]
harassment thresholds for impulsive sound sources (impact pile driving)
are defined for both SELcum and Peak SPL, with the threshold that
results in the largest modeled isopleth for each marine mammal hearing
group used to establish the Level A harassment isopleth. In this
project, Level A harassment isopleths based on SELcum were always
larger than those based on Peak SPL.
Table 6--Parameters of Pile Driving and Drilling Activity Used in User Spreadsheet
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile Vibratory pile
driver driver Impact pile driver Impact pile driver
Equipment type (installation/ (installation of (30-inch steel (36 and 48-inch Rock anchor (36- Rock anchor (48-
removal of 30-inch 36 and 48-inch piles) steel piles) inch steel piles) inch steel piles)
steel piles) steel piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............ Non-impulsive, Non-impulsive, Impulsive, Non- Impulsive, Non- Non-impulsive, Non-impulsive,
continuous. continuous. continuous. continuous. continuous. continuous
Source Level.................... 161.9 SPL......... 168.2 SPL......... 186.7 SS SEL*..... 186.7 SS SEL*..... 166.2 SPL......... 166.2 SPL
Weighting Factor Adjustment 2.5............... 2.5............... 2................. 2................. 2.5............... 2.5
(kHz).
(a)Activity duration (time) (a) 0:40.......... (a) 1:00.......... .................. .................. (a) 8:00.......... (a) 5:00
within 24 hours.
(b) Number of strikes per .................. .................. (b) 40............ (b) 100........... (240 mins *2)..... (300 mins *1)
pile (impact).
(c) Number of piles per day. (c) 4............. (c) 2............. (c) 2............. (c) 2............. (c) 2............. (c) 1
Propagation (xLogR)............. 15................ 15................ 15................ 15................ 15................ 15
Distance of source level 10................ 10................ 10................ 10................ 10................ 10
measurement (meters).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Data for all equipment types were for Propagation (xLogR) = 15 and distance of source level measurements was 10 meters.
* Largest isopleth distances for impact pile driving were all found when using SS SEL (see application for details) and SEL is the preferred metric.
The above input scenarios lead to a PTS isopleth distance (Level A
threshold) of 3.6 to 322.5 meters, depending on the marine mammal group
and scenario (Table 7).
Table 7--Calculated Distances to Level A Harassment Isopleths (m) During Pile Installation and Removal for each
Hearing Group
----------------------------------------------------------------------------------------------------------------
High
Pile size Low frequency Mid frequency frequency Phocid Otariid
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving/Removal:
30-inch piles............... 6 0.5 8.8 3.6 0.3
36-inch piles............... 20.6 1.8 30.5 12.5 0.9
48-inch piles............... 20.6 1.8 30.5 12.5 0.9
Impact Pile Driving:
30-inch piles............... 327.2 11.6 389.7 175.1 12.7
36-inch piles............... 602.7 21.4 717.9 322.5 23.5
48-inch piles............... 602.7 21.4 717.9 322.5 23.5
Rock Anchoring:
36-inch piles............... 60.7 5.4 89.7 36.9 2.6
48-inch piles............... 44.4 3.9 65.6 27 1.9
----------------------------------------------------------------------------------------------------------------
Note: a 10-meter shutdown zone will be implemented for all species and activity types to prevent direct injury
of marine mammals.
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of harbor seals that will inform the take
calculations. There is no density data for any of the species near Ward
Cove.
Harbor Seal
As discussed above anecdotal evidence suggests maximum group size
is up to three individuals in Ward Cove at one time. They are known to
occur year-round in the area with little seasonal variation in
abundance (Freitag (2017) as cited in 83 FR 37473) and local experts
estimate that there are about 1 to 3 harbor seals in Tongass Narrows
every day. To be conservative we will assume a group size of five
individuals in the project area each day.
Dall's Porpoise
Dall's porpoises are expected to only occur in the action area a
few times per year. Their relative rarity is supported by Jefferson et
al.'s (2019) presentation of historical survey data showing very few
sightings in the Ketchikan area and conclusion that Dall's porpoise
generally are rare in narrow waterways, like the Tongass Narrows. This
species is non-migratory; therefore, our occurrence estimates are not
dependent on season. We anticipate that one large Dall's porpoise pod
(15 individuals) (Freitag (2017), as cited in 83 FR37473) may be
present in the project area once each month during construction.
Harbor Porpoise
Harbor porpoises are non-migratory; therefore, our occurrence
estimates are not dependent on season. Freitag ((2017) as cited in 83
FR 37473) observed harbor porpoises in Tongass Narrows zero to one time
per month. Harbor porpoises observed in the project vicinity typically
occur in groups of one to five animals with an estimated maximum group
size of eight animals (83 FR 37473, August 1, 2018, Solstice 2018). For
our impact analysis, we are considering a group to consist of five
[[Page 12535]]
animals, a value on the high end of the typical group size. Based on
Freitag (2017), and supported by the reports of knowledgeable locals as
described in the application for IHA for Tongass Narrows (https://www.fisheries.noaa.gov/action/incidental-take-authorization-alaska-department-transportation-ferry-berth-improvements), it is estimated
that a maximum two groups (10) of harbor porpoises would enter Tongass
Narrows and potentially be exposed to project related noise each of the
four months of the project.
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate. As noted above, the
applicant only requested take of harbor seals, but we believe the
cryptic nature, small size, and dive duration of Dall's porpoise and
harbor porpoise make it possible that these two species could also be
taken by popping up inside the Level B harassment zone before shutdown
can occur (see below). We describe how we estimated their take below.
It is important to note that PSSA proposes to implement a shutdown
of pile driving activity if any marine mammal other than harbor seals
is observed within the Level B harassment zone (see Proposed
Mitigation). Therefore, the proposed take authorization is intended to
provide insurance against the event that marine mammals occur within
Level B harassment zones that cannot be fully observed by monitors. As
a result of this proposed mitigation, we do not believe that Level A
harassment is a likely outcome for these two species. While the
calculated Level A harassment zone is as large as 720 m for impact
driving of 48-in steel piles (ranging from 390 m for other impact
driving scenarios), this requires that an animal be present at that
range for the full assumed duration of pile strikes (expected to
require multiple hours). Given the PSSA's commitment to shut down upon
observation of other marine mammals, and the rarity of these animals
inside Ward Cove where the Level A harassment zones will be, we do not
expect that any of these other species would be present within a Level
A harassment zone for sufficient duration to actually experience PTS.
Harbor Seals
The take calculation was estimated based on the conservative group
size from above (5) multiplied by the number of expected groups per day
multiplied by the number of days of pile driving. Based on the
anecdotal observations, it is conservatively estimated that 2 groups of
5 harbor seals may occur within the Level B harassment zone every day
that pile driving may occur. Thus we estimate 5 animals in a group x 2
groups per day x 105 days = 1,050 times animals would occur within the
Level B harassment zone. The Level B harassment zones areas for trestle
construction and mooring dolphin construction differ in size because
more sound is expected to leak out of the cove into Tongass Narrows
when construction on the dolphins is toward the middle of the cove (see
Figure 6 of application). Nevertheless, it is expected that most of the
take will occur within Ward Cove (not Tongass Narrows) where the action
areas for trestle and dolphin construction overlap and are identical in
size, so take is not reduced despite the smaller area of trestle
effects.
The Level A harassment zone for harbor seals for impact pile
driving of 30-inch piles is 175 meters, and for impact driving of 36
and 48-inch piles, the zone is 325 meters. For other pile driving
activities the zones are much smaller. Impact pile driving would be
shut down before a harbor seal enters within 200 meters during impact
pile driving of all piles; however, take by Level A harassment of
harbor seals is requested outside the 200m shutdown zone for larger
piles with zones exceeding 200m. Impact driving would occur for no more
than 10 minutes per day on 20 days of construction. As above we use
group size of 5 individuals and expect 1 group per day to be exposed in
the Level A harassment zone. Although mere ``exposure'' within the
Level A harassment zone is not indicative of an animal incurring
auditory injury due to the fact that injury results from accumulation
of energy over an assumed duration of exposure, we conservatively
propose to authorize 100 Level A harassment takes of harbor seal (5
animals in a group x 1 groups per day x 20 days = 100 animals). Because
these animals exposed in the Level A harassment zone duplicate those
exposed in the Level B zone, the authorized Level B harassment take is
the number of Level B harassment zone exposures minus the Level A take
or 950 animals (1050-100).
Dall's Porpoise
As discussed above we assume a single group of 15 individuals in
the project area each month. The take calculation was estimated based
on the conservative group size from above (15) multiplied by the number
of expected groups per month (1) multiplied by the number of months of
pile driving for the project (4). Thus we estimate Level B harassment
take of 60 individuals (15 x 1 x 4).
Harbor Porpoise
As discussed above we assume a conservative group size of 5
individuals occurring no more than twice in the project area each
month. The take calculation was estimated based on the group size from
above (5) multiplied by the number of expected groups per month (2)
multiplied by the number of months of pile driving for the project (4).
Thus we estimate Level B harassment take of 40 individuals (5 x 2 x 4).
Effects of Specified Activities on Subsistence Uses of Marine Mammals
The availability of the affected marine mammal stocks or species
for subsistence uses may be impacted by this activity. The subsistence
uses that may be affected and the potential impacts of the activity on
those uses are described below. The information from this section is
analyzed to determine whether the necessary findings may be made in the
Unmitigable Adverse Impact Analysis and Determination section.
Subsistence harvest of harbor seals by Alaska Natives is not
prohibited by the MMPA. Since surveys of harbor seal subsistence
harvest in Alaska began in 1992, there have been declines in the number
of households hunting and harvesting seals in Southeast Alaska (Wolf et
al. 2013). Subsistence harvest data for the Clarence Strait stock
indicates an average annual harvest in the years 2004-2008 of 164
harbor seals (80 near Ketchikan) and an average annual harvest in the
years 2011-2012 of 40 harbor seals (summarized in Muto et al. 2016a
from Wolf et al. 2013). In 2008, two Steller sea lions were harvested
by Ketchikan-based subsistence hunters, but this is the only record of
sea lion harvest by residents of Ketchikan. In 2012, the community of
Ketchikan had an estimated subsistence take of 22 harbor seals (Wolf et
al. 2013). This is the most recent data for Ketchikan. The ADF&G has
not recorded harvest of cetaceans in the area (ADF&G 2018). Hunting
usually occurs in October and November (ADF&G 2009), but there are also
records of relatively high harvest in May (Wolfe et al. 2013).
In June 2019, attempts were made by PSSA to contact the Alaska
Harbor Seal Commission, the Alaska Sea Otter and Steller Sea Lion
Commission, and the Ketchikan Indian Community (KIC, Federal-recognized
Tribe) to discuss this
[[Page 12536]]
project. The Alaska Harbor Seal Commission is currently not
operational. Comments were not received from the Alaska Sea Otter and
Steller Sea Lion Commission. PSSA met with KIC and KIC submitted
comments for the Army Corps of Engineers permit for this project. They
did not express concerns about subsistence hunting.
Construction activities at the project site would be expected to
cause only short term, non-lethal disturbance of marine mammals.
Construction activities are localized and temporary in the previously
developed Ward Cove, mitigation measures will be implemented to
minimize disturbance of marine mammals in the action area, and, the
project will not result in significant changes to availability of
subsistence resources. Impacts on the abundance or availability of
either species to subsistence hunters in the region are thus not
anticipated.
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. 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, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure will be effective if
implemented (probability of accomplishing the mitigating result if
implemented as planned), the likelihood of effective implementation
(probability implemented as planned), and;
(2) the practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
The following mitigation measures are proposed in the IHA:
Schedule: Pile driving or removal must occur during
daylight hours. If poor environmental conditions restrict visibility
(e.g., from excessive wind or fog, high Beaufort state), pile
installation would be delayed;
Pile Driving Delay/Shut-Down: For use of in-water heavy
machinery/vessel (e.g., dredge), PSSA must implement a minimum shutdown
zone of 10 m radius around the pile/vessel. For vessels, PSSA must
cease operations and reduce vessel speed to the minimum required to
maintain steerage and safe working conditions. In addition, if an
animal comes within the shutdown zone (see Table 8) of a pile being
driven or removed, PSSA would shut down. The shutdown zone would only
be reopened if they observe the animal exiting the zone or when a
marine mammal has not been observed within the shutdown zone for a 15-
minute period. If pile driving is stopped, pile installation would not
commence if any marine mammals are observed anywhere within the Level A
harassment zone. Pile driving activities must only be conducted during
daylight hours when it is possible to visually monitor for marine
mammals. If a species for which authorization has not been granted, or
if a species for which authorization has been granted but the
authorized takes are met, PSSA must delay or shut-down pile driving if
the marine mammal approaches or is observed within the Level A and/or B
harassment zones. In the unanticipated event that the specified
activity clearly causes the take of a marine mammal in a manner
prohibited by the IHA, such as serious injury or mortality, the
protected species observer (PSO) on watch must immediately call for the
cessation of the specified activities and immediately report the
incident to the Chief of the Permits and Conservation Division, Office
of Protected Resources, NMFS, and NMFS Alaska Regional Office.
Table 8--Shutdown and Monitoring Zones for Each Activity Type and Stock
----------------------------------------------------------------------------------------------------------------
Other marine Level B harbor
Harbor seal mammal seal
Pile size shutdown shutdown monitoring
distance (m) distance (m) zone (m)
----------------------------------------------------------------------------------------------------------------
Vibratory Pile Driving/Removal:
30-inch piles............................................... 10 3,645 3,645
36-inch piles............................................... 15 3,645 3,645
48-inch piles............................................... 15 3,645 3,645
Impact Pile Driving:
30-inch piles............................................... 200 3,645 3,645
36-inch piles............................................... 200 3,645 3,645
48-inch piles............................................... 200 3,645 3,645
Rock Anchoring:
36-inch piles............................................... 40 3,645 3,645
48-inch piles............................................... 40 3,645 3,645
All Other Activities:
Any activity................................................ 10 N/A N/A
----------------------------------------------------------------------------------------------------------------
Note: A Level A harbor seal monitoring zone is implemented for impact pile driving of 36 and 48-inch diameter
piles out to the extent of the Level A harassment zone (325 m). Level B monitoring zone (for the three species
with authorized take) and other marine mammal shutdown distance of 3,645 m reflects the farthest distance
before sound is inhibited by land.
[[Page 12537]]
Soft-start: For all impact pile driving, a ``soft start''
technique must be used at the beginning of each pile installation day,
or if pile driving has ceased for more than 30 minutes, to allow any
marine mammal that may be in the immediate area to leave before
hammering at full energy. The soft start requires PSSA to provide an
initial set of three strikes from the impact hammer at reduced energy,
followed by a 30 second waiting period, then two subsequent 3-strike
sets. If any marine mammal is sighted within the Level A shutdown zone
prior to pile-driving, or during the soft start, PSSA must delay pile-
driving until the animal is confirmed to have moved outside and is on a
path away from the Level A harassment zone or if 15 minutes have
elapsed since the last sighting;
Sediment control: All material that comes out of the top
of the pile during pile driving (drill cutting discharge) must be
collected on a barge and transported to a permitted upland location for
disposal. Pile driving, temporary pile removal, and collection of
excavated material operations must be surrounded by a 50-feet deep silt
curtain; and
Other best management practices: PSSA will drive all piles
with a vibratory hammer to the maximum extent possible (i.e., until a
desired depth is achieved or to refusal) prior to using an impact
hammer. PSSA will also use the minimum hammer energy needed to safely
install the piles.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stock for
subsistence uses.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
Visual Monitoring
Monitoring must be conducted 30 minutes before, during, and 30
minutes after pile driving and removal activities. In addition,
observers shall record all incidents of marine mammal occurrence,
regardless of distance from activity, and shall document any behavioral
reactions in concert with distance from piles being driven or removed.
Pile driving activities include the time to install a single pile or
series of piles, as long as the time elapsed between uses of the pile
driving equipment is no more than thirty minutes.
Four PSO's would be used to monitor the project and their locations
are shown in Figure 12 of the monitoring plan. A primary PSO must be
placed near the project site in Ward Cove where pile driving would
occur. The primary purpose of this observer is to monitor and implement
the Level A shutdown and monitoring zones. Three additional PSOs must
be positioned in order to focus on monitoring the Level B harassment
and other species shutdown zone. PSOs would scan the waters using
binoculars, and/or spotting scopes, and would use a handheld GPS or
range-finder device to verify the distance to each sighting from the
project site. All PSOs would be trained in marine mammal identification
and behaviors and are required to have no other project-related tasks
while conducting monitoring. The following measures also apply to
visual monitoring:
(1) Monitoring must be conducted by NMFS-approved qualified
observers, who will be placed at the best vantage point(s) practicable
to monitor for marine mammals and implement shutdown/delay procedures
when applicable by calling for the shutdown to the hammer operator.
Qualified observers are trained biologists, with the following minimum
qualifications:
(a) Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
(b) Advanced education in biological science or related field
(undergraduate degree or higher required);
(c) Experience and ability to conduct field observations and
collect data according to assigned protocols (this may include academic
experience);
(d) Experience or training in the field identification of marine
mammals, including the identification of behaviors;
(e) Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
(f) Writing skills sufficient to prepare a report of observations
including but not limited to the number and species of marine mammals
observed; dates and times when in-water construction activities were
conducted; dates and times when in-water construction activities were
suspended to avoid potential incidental injury from construction sound
of marine mammals observed within a defined shutdown zone; and marine
mammal behavior; and
(g) Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary; and
(2) PSSA shall submit observer CVs for approval by NMFS.
A draft marine mammal monitoring report would be submitted to NMFS
within 90 days after the completion of
[[Page 12538]]
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. It will include an overall description of work
completed, a narrative regarding marine mammal sightings, and
associated marine mammal observation data sheets. Specifically, the
report must include:
Dates and times (begin and end) of all marine mammal
monitoring;
Construction activities occurring during each daily
observation period, including how many and what type of piles were
driven or removed and by what method (i.e., impact or vibratory);
Weather parameters and water conditions during each
monitoring period (e.g., wind speed, percent cover, visibility, sea
state);
The number of marine mammals observed, by species,
relative to the pile location and if pile driving or removal was
occurring at time of sighting;
Age and sex class, if possible, of all marine mammals
observed;
PSO locations during marine mammal monitoring;
Distances and bearings of each marine mammal observed to
the pile being driven or removed for each sighting (if pile driving or
removal was occurring at time of sighting);
Description of any marine mammal behavior patterns during
observation, including direction of travel;
Number of individuals of each species (differentiated by
month as appropriate) detected within the monitoring zone, and
estimates of number of marine mammals taken, by species (a correction
factor may be applied to total take numbers, as appropriate);
Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting behavior of the animal, if
any;
Description of attempts to distinguish between the number
of individual animals taken and the number of incidences of take, such
as ability to track groups or individuals; and
An extrapolation of the estimated takes by Level B
harassment based on the number of observed exposures within the Level B
harassment zone and the percentage of the Level B harassment zone that
was not visible, when applicable.
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, PSSA shall report the
incident to the Office of Protected Resources (OPR), NMFS and to the
regional stranding coordinator as soon as feasible. The report must
include the following information:
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive;
If available, photographs or video footage of the
animal(s); and
General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any 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).
Pile driving and drilling activities have the potential to disturb
or displace marine mammals. Specifically, the project activities may
result in take, in the form of Level A harassment and Level B
harassment from underwater sounds generated from pile driving and
removal and DTH drilling. 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 behavioral disturbance, TTS, and PTS. No mortality is
anticipated given the nature of the activity and measures designed to
minimize the possibility of injury to marine mammals. The potential for
harassment is minimized through the construction method and the
implementation of the planned mitigation measures (see Proposed
Mitigation section).
The Level A harassment zones identified in Table 7 are based upon
an animal exposed to impact pile driving multiple piles per day.
Considering duration of impact driving each pile (up to 3 minutes) and
breaks between pile installations (to reset equipment and move pile
into place), this means an animal would have to remain within the area
estimated to be ensonified above the Level A harassment threshold for
multiple hours. This is highly unlikely given marine mammal movement
throughout the area. If an animal was exposed to accumulated sound
energy, the resulting PTS would likely be small (e.g., PTS onset) at
lower frequencies where pile driving energy is concentrated.
Behavioral responses of marine mammals to pile driving at the
project site, if any, are expected to be mild and temporary. Marine
mammals within the Level B harassment zone may not show any visual cues
they are disturbed by activities (as noted during modification to the
Kodiak Ferry Dock) or could become alert, avoid the area, leave the
area, or display other mild responses that are not observable such as
changes in vocalization patterns. Given the short duration of noise-
generating activities per day and that pile driving and removal would
occur across 4-5 months, any harassment would be temporary. There are
no other areas or times of known biological importance for any of the
affected species.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the stocks' ability
to recover. In combination, we believe that these
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factors, as well as the available body of evidence from other similar
activities, demonstrate that the potential effects of the specified
activities will have only minor, short-term effects on individuals. The
specified activities are not expected to impact rates of recruitment or
survival and will therefore not result in population-level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
No mortality is anticipated or authorized;
Authorized Level A harassment would be very small amounts
and of low degree;
PSSA would implement mitigation measures such as vibratory
driving piles to the maximum extent practicable, soft-starts, silt
curtains, removal of potentially contaminated sediments, and shut
downs; and
Monitoring reports from similar work in Alaska have
documented little to no effect on individuals of the same species
impacted by the specified activities.
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 Section 101(a)(5)(D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so, in practice, where estimated numbers are
available, NMFS compares the number of individuals taken to the most
appropriate estimation of abundance of the relevant species or stock in
our determination of whether an authorization is limited to small
numbers of marine mammals. Additionally, other qualitative factors may
be considered in the analysis, such as the temporal or spatial scale of
the activities.
The amount of take NMFS proposes to authorize is 3.8 percent of the
Clarence Strait stock's best population estimate for harbor seals. The
Alaska stock of Dall's porpoise has no official NMFS abundance estimate
as the most recent estimate is greater than eight years old.
Nevertheless, the most recent estimate was 83,400 animals and it is
highly unlikely this number has drastically declined. Therefore, the 60
authorized takes of this stock clearly represent small numbers of this
stock. The take for harbor porpoise is 4.1 percent of the stock. These
are all likely conservative estimates because they assume all takes 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
In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
That is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) Placing physical barriers
between the marine mammals and the subsistence hunters; and (2) That
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
As discussed above in the subsistence uses section, subsistence
harvest of harbor seals and other marine mammals is rare in the area
and local subsistence users have not expressed concern about this
project. All project activities will take place within the industrial
area of Tongass Narrows and Ward Cove immediately adjacent to Ketchikan
where subsistence activities do not generally occur. The project also
will not have an adverse impact on the availability of marine mammals
for subsistence use at locations farther away, where these construction
activities are not expected to take place. Some minor, short-term
harassment of the harbor seals could occur, but any effects on
subsistence harvest activities in the region will be minimal, and not
have an adverse impact.
Based on the effects and location of the specified activity, and
the mitigation and monitoring measures, NMFS has preliminarily
determined that there will not be an unmitigable adverse impact on
subsistence uses from PSSA's planned activities.
Endangered Species Act (ESA)
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally, in this case with the Alaska Region Protected
Resources Division Office, whenever we propose to authorize take for
endangered or threatened species.
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to PSSA to conduct the Ward Cove Cruise Ship Dock project
near Ketchikan, Alaska for one year from the date of issuance, provided
the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the proposed IHA can be found
at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this Notice of Proposed IHA for the proposed Ward
Cove Cruise Ship Dock 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-year Renewal IHA
following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical, or nearly
identical, activities as described in the Specified Activities
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section of this notice is planned or (2) the activities as described in
the Specified Activities section of this notice would not be completed
by the time the IHA expires and a Renewal would allow for completion of
the activities beyond that described in the Dates and Duration section
of this notice, provided all of the following conditions are met:
A request for renewal is received no later than 60 days
prior to the needed Renewal IHA effective date (recognizing that
Renewal IHA expiration date cannot extend beyond one year from
expiration of the initial IHA);
The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested Renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take);
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: February 26, 2020.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2020-04280 Filed 3-2-20; 8:45 am]
BILLING CODE 3510-22-P