[Federal Register Volume 88, Number 71 (Thursday, April 13, 2023)]
[Notices]
[Pages 22411-22433]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-07729]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XC757]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Pile Driving and Removal to Improve
the Auke Bay East Ferry Terminal
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the Alaska Department of
Transportation and Public Facilities (ADOT&PF) for authorization to
take marine mammals incidental to pile driving to improve the Auke Bay
East Ferry Terminal in Juneau, 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
[[Page 22412]]
activities. NMFS is also requesting comments on a possible one-time, 1-
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
authorization and agency responses will be summarized in the final
notice of our decision.
DATES: Comments and information must be received no later than May 15,
2023.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email 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, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at
www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Craig Cockrell, 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. 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 proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is 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 IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs 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 September 13, 2022, NMFS received a request from ADOT&PF for an
IHA to take marine mammals incidental to vibratory and impact pile
driving to improve the Auke Bay East Ferry Terminal. Following NMFS'
review of the application, ADOT&PF submitted a revised version on
January 11, 2023. The application was deemed adequate and complete on
February 14, 2023. The ADOT&PF's request is for the incidental take of
small numbers of 11 species or stocks of marine mammals, in the form of
Level B harassment for all and, for harbor seals and harbor porpoise,
including take by Level A harassment. Neither ADOT&PF nor NMFS expect
serious injury or mortality to result from this activity and,
therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
ADOT&PF is proposing maintenance improvements to the existing
Alaska Marine Highway System (AMHS) Auke Bay East Berth marine
terminal. The activity includes removal of existing piles and the
installation of both temporary and permanent piles of various sizes.
Takes of marine mammals by Level A and Level B harassment would occur
due to both impact and vibratory pile driving and removal. The project
would occur in Auke Bay which is located in southeast Alaska in close
proximity to the City of Juneau. Construction activities are expected
to over a four month period in fall 2023. It is expected to take up to
61 days to complete the pile driving activities.
The Auke Bay Ferry Terminal is located along the north shore of
Auke Bay and is a major hub of the Southeast and Gulf of Alaska routes
of the AMHS. The purpose of the Project is to restore the service life
of the AMHS Auke Bay East Berth ferry terminal, which was originally
built in 1982. The dolphins have undergone several repair projects and
are currently in need of full replacement to keep the facility safe and
usable for the AMHS vessels that frequent the facility.
Dates and Duration
The proposed activities are expected to occur between October 1,
2023 and September 30, 2024. It is expected to take up to 61 non-
consecutive days of in water work over a four month work window to
complete the pile driving activities. Pile driving would be completed
intermittently throughout the daylight hours. All pile driving is
expected to be completed during one phase of construction.
Specific Geographic Region
Auke Bay is an estuary at the southern end of Lynn Canal, located
approximately 18 kilometers (km) (11 miles (mi)) north-northwest of
downtown Juneau. The bay is one of many that lead to a larger system of
[[Page 22413]]
glacial fjords connecting various channels with the open ocean. Auke
Bay is approximately 130 km (80.7 mi) inland from the Gulf of Alaska
(Figure 1). Auke Bay contains several small islands and reefs within
the 11 square kilometer (km\2\) (4.25 square mile (mi\2\)) embayment.
While most of the bay is relatively shallow, reaching depths of 40 to
60 meters (m) (131 to 197 feet (ft)), depths of more than 100 m (328
ft) are found near Coghland Island (see Figure 1-2 in the IHA
application). Pile installation and removal at the ferry terminal would
occur in waters ranging in depth from less than 1 m (3.3 ft) near shore
to approximately 11 m (35 ft).
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TN13AP23.113
BILLING CODE 3510-22-C
[[Page 22414]]
Detailed Description of the Specified Activity
The ferry terminal improvements include the removal of 47 existing
steel pipe piles. Once the existing piles are removed, up to 20 new
steel pipe piles (30-inch (in) (76.2 centimeters (cm)) diameter; 10
plumb, 10 battered) would be installed as berthing dolphins. Eight new
steel pipe piles (24-in diameter (61 cm); 4 plumb, 4 battered) would be
installed as float restraints. Four new steel pipe piles (18-in
diameter (45.7 cm)) would be installed as gangway and platform support.
The installation and removal of 32 temporary 24-in steel pipe piles
would be completed to support permanent pile installation. Vibratory
and impact hammers will be used for the installation and removal of all
piles (Table 1). Removal of piles would be conducted using vibratory
hammers. After new piles are set with a vibratory hammer, installed
piles would be proofed with an impact hammer to verify the structural
capacity of the pile embedment. The work would be completed at the
existing Auke Bay Ferry Terminal in Juneau, Alaska. Work on the
terminal would be completed within 1-year starting in October and
completion in September.
Table 1--Number and Types of Piles To Be Installed and Removed
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Strikes Duration Piles per
Pile diameter and type Number of per pile per pile day Days of
piles (impact) (minutes) (range) activity
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Pile Installation
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30 in Steel Plumb Piles (Permanent; Berthing Dolphins) 10 1,000 60 1.5 (1-2) 7
30 in Steel Batter Piles (Permanent; Berthing 10 1,000 60 1.5 (1-2) 7
Dolphins)............................................
24 in Steel Plumb Piles (Permanent; Float Restraint).. 4 1,000 60 1.5 (1-2) 3
24 in Steel Batter Piles (Permanent; Float Restraint). 4 1,000 60 1.5 (1-2) 3
18 in Steel Plumb Piles (Permanent; Gangway/Platform 4 800 60 1.5 (1-2) 3
Support).............................................
24 in Steel Piles (Temporary)......................... 32 500 30 3 (2-4) 11
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Pile Removal
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18 in Steel Plumb Piles (Existing).................... 47 N/A 30 3 (2-4) 16
24 in Steel Piles (Temporary)......................... 32 N/A 30 3 (2-4) 11
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Total............................................. 143 .......... ........... ......... 61
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Above-water construction would include replacement of the catwalk
access gangway, refurbishment of the catwalks, lighting upgrades along
dolphins and catwalk, removal and replacement of electrical components
as needed to perform dolphin replacement work, and installation of
cathodic protection anodes on all piles. This above-water work is not
expected to result in any take. Noise generated above the water would
not be transmitted into the water and, there are no major pinniped
haulouts located near the project area, therefore airborne noise is
therefore not considered further in this document.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, incorporated here by reference, instead of
reprinting the information. Additional information regarding population
trends and threats may be found in NMFS' Stock Assessment Reports
(SARs; 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' website (https://www.fisheries.noaa.gov/find-species).
Table 2 lists all species or stocks for which take is expected and
proposed to be authorized for this activity, and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. 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'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality from
anthropogenic sources are included here as gross indicators of the
status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' 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' U.S. 2021 SARs, and NMFS has reviewed the most current
information for all species, including those updated in the Draft 2022
SARs.
On January 24, 2023, NMFS published the draft 2022 SARs (https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region). The Alaska and Pacific Ocean SARs
include proposed updates to the humpback whale and harbor porpoise
stock structures. The new humpback whale stock structure, if finalized,
would modify the MMPA-designated stocks to align more closely with the
ESA-designated DPSs. The new harbor porpoise stock structure, if
finalized, would split the Southeast Alaska stock into three new
stocks. Please refer to the draft 2022 Alaska (Young et al., 2023) and
Pacific Ocean SARs for additional information.
[[Page 22415]]
NMFS Office of Protected Resources, Permits and Conservation
Division has generally considered peer-reviewed data in draft SARs
(relative to data provided in the most recent final SARs), when
available, as the best available science, and has done so in this rule
for all species and stocks, with the exception of a new proposal to
revise humpback whale stock structure. Given that the proposed changes
to the humpback whale stock structure involve application of NMFS's
Guidance for Assessing Marine Mammals Stocks and could be revised
following consideration of public comments, it is more appropriate to
conduct our analysis in this proposed IHA based on the status quo stock
structure identified in the most recent final SARs (2021; Carretta et
al., 2022; Muto et al., 2022).
All values presented in Table 2 are the most recent available at
the time of publication (including from the draft 2022 SARs) and are
available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments).
Table 2--Species Likely Impacted by the Specified Activities
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ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Central North Pacific.. -/-; Y 10,103 (0.3, 7,890, 3.4 4.46
2006).
Minke whale..................... Balaenoptera Alaska................. -/-; N N/A (N/A, N/A, N/A)... UND 0
acutorostrada.
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer whale.................... Orcinus orca........... Alaska Resident........ -/-; N 1,920 (N/A, 1,920, 19 1.3
2019).
West Coast Transient... -/-; N 349 (N/A, 349, 2018).. 3.5 0.4
Pacific white-sided dolphin..... Lagenorhynchus North Pacific.......... -/-; N 26,880 (N/A, N/A, UND 0
obliquidens. 1990).
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Southern Southeast -/-; Y 890 (0.37; 610; 2019). 6.1 7.4
Alaska Inland Waters.
Dall's porpoise................. Phocoenoides dalli..... Alaska................. -/-; N UND (UND, UND, 2015).. UND 37
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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 DPS............ -/-; N 43,201 (N/A, 43,201, 2,592 112
2017).
Western DPS............ E/D; Y 52,932 (N/A, 53,932, 318 254
2019).
California sea lion............. Zalophus californianus. U.S.................... -/-; N 257,606 (N/A, 233,515, 14,011 >321
2014).
Northern fur seal............... Callorhinus ursinus.... Eastern Pacific........ -/-; Y 626,618 (0.2, 530,376, 11,403 373
2019).
Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Lynn Canal/Stephens -/-; N 13,388 (N/A, 11,867, 214 50
Passage. 2016).
Northern Elephant Seal.......... Mirounga angustirostris California............. -/-; N 187,386 (N/A, 85,369, 5,122 13.7
2013).
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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: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
As indicated above, all 11 species (with 13 managed stocks) in
Table 2 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. All species that could
potentially occur in the proposed survey areas are included in Table 3-
1 of the IHA application. The spatial and temporal occurrence of gray
whales and fin whales in the area is such that take is not expected to
occur. Sightings of gray whales and fin whales are uncommon in the
inland waters of southeast Alaska. These species are typically seen
closer to the open waters of the Gulf of Alaska. Additionally, the
timing of the project (October-December) coincides with the period when
these species are expected to be further south in their respective
breeding areas. Take of gray whales and fin whales has not been
requested nor is proposed to be authorized and these species are not
considered further in this document. The take of Northern fur seals was
not requested by the applicant, but further communication with the NMFS
Alaska Regional Office resulted in their inclusion in species that
inhabit the area as well as being at risk for take during the
construction activities (Wright, S., pers. comm.).
Humpback Whale
Humpback whales in the project area are from the Central North
Pacific stock but may be of the Hawaii or Mexico Distinct Population
Segments (DPS). Humpback whales migrate to southeast Alaska in spring
to feed after months of fasting in equatorial breeding grounds in
Hawaii and Mexico. Humpback whales found in the project areas are
predominantly members of the Hawaii DPS (98 percent probability in
[[Page 22416]]
Southeast Alaska), which is not listed under the ESA. However, based on
a comprehensive photo-identification study, members of the Mexico DPS,
which is listed as threatened, have a small potential to occur in the
project location (2 percent probability in Southeast Alaska) (Wade,
2021). Peak abundance of humpback whales in southeast Alaska typically
occurs during late summer to early fall. Most humpback whales begin
returning to southern breeding grounds in fall or winter. However, due
to temporal overlap between whales departing and returning, humpbacks
can be found in Alaskan feeding grounds in every month of the year
(Baker et al., 1985; Straley, 1990; Wynne and Witteveen, 2009). It is
also common for some humpback whales to overwinter in areas of
southeast Alaska. It is thought that those humpbacks that remain in
southeast Alaska do so in response to the availability of winter
schools of fish, such as herring (Straley, 1990).
Southeast Alaska is considered a biologically important area for
feeding humpback whales between March and May (Ellison et al. 2012).
Most humpback whales migrate to other regions during winter to breed,
but over-wintering (non-breeding) humpback whales have been noted and
may be increasingly common (Straley, 1990). In Alaska, humpback whales
filter feed on tiny crustaceans, plankton, and small fish such as
walleye pollock, Pacific sand lance, herring, eulachon, and capelin
(Witteveen et al., 2012). It is common to observe groups of humpback
whales cooperatively bubble feeding.
Use of Auke Bay by humpback whales is intermittent and irregular
year-round. During winter, researchers have documented 1 to 19
individual humpback whales per month in waters close to the project
area, including Lynn Canal (Moran et al., 2018a; Straley et al., 2018).
Group sizes in southeast Alaska generally range from one to four
individuals (Dahlheim et al., 2009).
Minke Whale
Minke whales in Southeast Alaska are part of the Alaska stock (Muto
et al., 2022). Dedicated surveys for cetaceans in Southeast Alaska
found that minke whales were scattered throughout inland waters from
Glacier Bay and Icy Strait to Clarence Strait, with small
concentrations near the entrance of Glacier Bay. All sightings were of
single minke whales, except for a single sighting of multiple minke
whales. Surveys took place in spring, summer, and fall, and minke
whales were present in low numbers in all seasons and years. No
information appears to be available on the winter occurrence of minke
whales in Southeast Alaska (Dahlheim et al., 2009). Anecdotal
observations suggest that minke whales do not enter Auke Bay but their
occurrence in Southeast Alaska could result in their presences in the
Project area.
Killer Whale
Killer whales have been observed in all the world's oceans, but the
highest densities occur in colder and more productive waters found at
high latitudes (NMFS 2016a). Killer whales occur along the entire
Alaska coast, in British Columbia and Washington inland waterways, and
along the outer coasts of Washington, Oregon, and California (NMFS,
2016a). There are three distinct ecotypes, or forms, of killer whales
recognized: resident, transient, and offshore. The three ecotypes
differ morphologically, ecologically, behaviorally, and genetically.
Based on data regarding association patterns, acoustics, movements, and
genetic differences, eight killer whale stocks are now recognized
within the Pacific U.S. Exclusive Economic Zone. This application
considers only the Eastern North Pacific Alaska Resident Stock (Alaska
Resident Stock), Eastern North Pacific Northern Resident Stock
(Northern Resident Stock), and West Coast Transient Stock, because all
other stocks occur outside the geographic area under consideration
(Muto et al., 2022).
Transient killer whales hunt and feed primarily on marine mammals,
while residents forage primarily on fish. Transient killer whales feed
primarily on harbor seals, Dall's porpoises, harbor porpoises, and sea
lions. Resident killer whale populations in the eastern North Pacific
feed mainly on salmonids, showing a strong preference for Chinook
salmon (NMFS, 2016a).
No systematic studies of killer whales have been conducted in or
around Auke Bay. Killer whales were observed infrequently (on 11 of 135
days) during monitoring nearby in Hoonah, 54 km west of Auke Bay, and
most were recorded in deeper, offshore waters (Berger ABAM, 2016).
Dalheim et al. (2009) observed transient killer whales within Lynn
Canal, Icy Strait, Stephens Passage, Frederick Sound, and upper Chatham
Strait. Transient killer whales tend to transit through Lynn Canal and
occasionally enter Auke Bay to target local harbor seal, harbor
porpoise, or Steller sea lion populations, but do not linger in the
Project area (K. Savage, pers. comm.).
Pacific White-Side Dolphin
Pacific white-sided dolphins are a pelagic species inhabiting
temperate waters of the North Pacific Ocean and along the coasts of
California, Oregon, Washington, and Alaska (Muto et al. 2022). Despite
their distribution mostly in deep, offshore waters, they may also be
found over the continental shelf and in nearshore waters, including
inland waters of Southeast Alaska (Ferrero and Walker, 1996). They prey
on squid and small schooling fish such as capelin, sardines, and
herring, are known to work in groups to herd schools of fish, and can
dive underwater for up to 6 minutes to feed (Morton, 2006).
Scientific studies and data are lacking relative to the presence or
abundance of Pacific white-sided dolphins in or near Auke Bay. When
Pacific white-sided dolphins have been observed, sighting rates were
highest in spring and decreased throughout summer and fall (Dahlheim et
al., 2009). Most observations of Pacific white-sided dolphins occur off
the outer coast or in inland waterways near entrances to the open
ocean. According to NOAA (Muto et al., 2022), aerial surveys in 1997
sighted one group of 164 Pacific white-sided dolphins in the Dixon
Entrance to the south of Auke Bay. These observational data, combined
with anecdotal information, indicate that there is a small potential
for Pacific white-sided dolphins to occur in the Project area.
Harbor Porpoise
The Southeast Alaska stock of harbor porpoises ranges from Cape
Suckling to the Canada border (Muto et al., 2022). Harbor porpoises
frequent primarily coastal waters in southeast Alaska (Dalheim et al.,
2009) and occur most frequently in waters less than 100 m (328 ft) deep
(Hobbs and Waite, 2010). Harbor porpoises forage in waters less than
200 m (656 ft) deep on small pelagic schooling fish such as herring,
cod, pollock, octopus, smelt, and bottom-dwelling fish, occasionally
feeding on squid and crustaceans (Bj[oslash]rge and Tolley 2009; Wynne
et al., 2011). Calving generally occurs from May to August, but can
vary by region.
Although there have been no systematic studies or observations of
harbor porpoises specific to Auke Bay, there is the potential for them
to occur within the project area. Abundance data for harbor porpoises
in southeast Alaska were collected during 18 seasonal surveys spanning
22 years, from 1991 to 2012. During that study, a total of 398 harbor
porpoises were observed in the northern inland waters of southeast
[[Page 22417]]
Alaska, including Lynn Canal (Dahlheim et al., 2015). Recent monitoring
from ADOT&PF from within Auke Bay observed a total of 28 animals over a
25 day period (ADOT&PF, 2021. NMFS also completed observations in Auke
Bay where 62 groups of harbor porpoises were seen over a 60-hour
period. The survey was conducted from March through June in 2021.
Dall's Porpoise
Dall's porpoises are found throughout the North Pacific, from
southern Japan to southern California and north to the Bering Sea. All
Dall's porpoises in Alaska are members of the Alaska stock, and those
off California, Oregon, and Washington are part of a separate stock.
This species can be found in offshore, inshore, and nearshore habitat,
but prefers waters more than 183 meters deep (Dahlheim et al., 2009;
Jefferson, 2009).
No systematic studies of Dall's porpoise abundance or distribution
have occurred in Auke Bay; however, Dall's porpoises have been
consistently observed in Lynn Canal, Stephens Passage, upper Chatham
Strait, Frederick Sound, and Clarence Strait (Dalheim et al., 2000).
The species is generally found in waters in excess of 600 feet (183
meters) deep, which do not occur in Auke Bay. Despite generalized water
depth preferences, Dall's porpoises may occur in shallower waters.
Moran et al. (2018a) recently mapped Dall's porpoise distributions in
bays, shallow water, and nearshore areas of Prince William Sound,
habitats not typically utilized by this species. A lone Dall's porpoise
was sighted in the Level B harassment zone during construction
activities conducted by ADOT&PF at Auke Bay in 2021 (ADOT&PF, 2021). If
Dall's porpoises occur in the Project area, they will likely be present
in March or April, given strong seasonal patterns observed in nearby
areas of Southeast Alaska (Dalheim et al., 2009).
Steller Sea Lion
Steller sea lions are found throughout the northern Pacific Ocean,
including coastal and inland waters from Russia (Kuril Islands and the
Sea of Okhotsk), east to Alaska, and south to central California
(A[ntilde]o Nuevo Island). Steller sea lions were listed as threatened
range-wide under the ESA on November 26, 1990 (55 FR 49204, November
26, 1990); they were subsequently partitioned into the western and
eastern DPSs (wDPS and eDPS, respectively) in 1997 (Allen and Angliss,
2010). The eDPS remained classified as threatened (62 FR 24345, May 5,
1997) until it was delisted in November 2013, while the wDPS (those
individuals west of 144[deg] W longitude or Cape Suckling, Alaska) was
upgraded to endangered status following separation of the stocks, and
it remains listed as endangered.
The majority of Steller sea lions that inhabit Southeast Alaska are
part of the eDPS; however, branded individuals from the wDPS make
regular movements across the 144[deg] longitude boundary to the
northern ``mixing zone'' haulouts and rookeries within southeast Alaska
(Jemison et al., 2013). While haulouts and rookeries in the northern
portion of Southeast Alaska may be important areas for wDPS animals,
there continues to be little evidence that their regular range extends
to the southern haulouts and rookeries in Southeast Alaska (Jemison et
al., 2018). However, genetic data analyzed in Hastings et al. (2020)
indicated that up to 1.4 percent of Steller sea lions near the Project
area may be members of the wDPS, which NMFS recommends using in their
2020 guidance (NMFS, 2020).
Steller sea lions are opportunistic predators, feeding primarily on
a wide variety of fishes and cephalopods, including Pacific herring
(Clupea pallasi), walleye pollock (Gadus chalogramma), capelin
(Mallotus villosus), Pacific sand lance (Ammodytes hexapterus), Pacific
cod (Gadus machrocephalus), salmon (Oncorhynchus spp.), and squid
(Teuthida spp.) (Jefferson et al., 2008; Wynne et al., 2011). Steller
sea lions do not generally eat every day, but tend to forage every one
to two days and return to haulouts to rest between foraging trips
(Merrick and Loughlin, 1997; Rehberg et al., 2009).
The action area is not located in or near designated critical
habitat for the wDPS of Steller sea lions. In southeast Alaska,
critical habitat for the wDPS includes a terrestrial zone, an aquatic
zone, and an in-air zone that extends 3,000 ft (0.9 km) landward,
seaward, and above, respectively, any designated major rookery and
major haulout. Steller sea lions are common within the project area;
however, systematic counts or surveys have not been completed. The
species generally occurs in Auke Bay only during winter. In the marine
mammal monitoring report for a project completed at the same facility
by ADOT, 30 Steller sea lions were observed within the behavioral
disturbance zone during pile driving or drilling (i.e., documented as
Level B harassment take) (ADOT&PF, 2021). The Auke Bay boating
community observes Steller sea lions transiting between Auke Bay and
the Benjamin Island haulout regularly during winter and provides
anecdotal reports of Steller sea lions utilizing Fritz Cove in winter
months. Most individuals that frequent Auke Bay use the major haulout
on Benjamin Island in Lynn Canal (approximately 34 mi (54.7 km) from
the project location), but several other haulouts are located within 20
to 30 km (12 to 19 mi) of the project area.
California Sea Lion
California sea lions have been separated into five genetically
distinct stocks, with the U.S. Stock also known as the Pacific
Temperate Stock (Carretta et al., 2022). Male California sea lions
disperse widely from their breeding rookeries in southern California to
forage as far north as Canada (Carretta et al., 2022), with some
individuals observed dispersing farther north.
The U.S. stock of California sea lions have a wide range, typically
from the border of the United States and Mexico (NMFS, 2019c). During
the winter males commonly migrate to feeding grounds off California,
Oregon, Washington, British Columbia and recently Southeast Alaska.
There is an active unusual mortality event declared for the U.S. stock
of California sea lions but this is mostly limited to southern
California. Females and pups on the other hand stay close to breeding
colonies until the pups have weened. The furthest north females have
been observed is off the coast of Washington and Oregon during warm
water years (NMFS, 2019c). While California sea lions aren't common in
Alaska, one was present on the docks in Statter Harbor within Auke Bay
in 2017 (NOAA, 2017).
California sea lions feed primarily offshore in coastal waters.
They are opportunistic predators and eat a variety of prey including
squid, anchovies, mackerel, rockfish and sardines (NMFS, 2019c).
California sea lion breeding areas are mostly in southern California
and are not expected to spatially overlap with the project area.
Northern Fur Seal
Northern fur seals occur from southern California north to the
Bering Sea and west to the Sea of Okhotsk and Honshu Island, Japan.
During the summer breeding season, most of the worldwide population is
found on the Pribilof Islands (St. Paul Island and St. George Island)
in the southern Bering Sea, with the remaining animals on rookeries in
Russia, on Bogoslof Island in the southern Bering Sea, on San Miguel
Island off southern California, and on the Farallon Islands off central
California (Muto et al. 2022). Northern fur seals feed on a variety of
prey including, squid, walleye pollock
[[Page 22418]]
(Gadus chalcogrammus), Pacific hearing (Clupea pallasii), and capelin
(Mallotus villosus) (Gomez et al., 2015). Breeding and important
haulouts areas are not expected to spatially overlap with the project
area.
Northern fur seals are rare in the Auke Bay in general, but one
lone animal was sighted swimming in the Gastineau Channel in 2019. In
2021 three Northern fur seals were stranded near Juneau, one in
Gastineau Channel, one onshore about two miles Northwest of the action
area, and a third on the west side of Douglas Island. Early in 2023
another northern fur seal was stranded in Sitka harbor (Wright, S.,
pers. comm.).
Harbor Seal
Harbor seals range from Baja California north along the west coasts
of California, Oregon, Washington, British Columbia, and Southeast
Alaska; west through the Gulf of Alaska, Prince William Sound, and the
Aleutian Islands; and north in the Bering Sea to Cape Newenham and the
Pribilof Islands. Harbor seals occur year-round in the inside passages
of southeast Alaska and are regularly sighted in Auke Bay. Harbor seals
forage on fish and invertebrates (Orr et al., 2004) including capelin,
eulachon (Thaleichthys pacificus), cod, pollock, flatfish, shrimp,
octopus, and squid (Wynne, 2012). They are opportunistic feeders that
forage in marine, estuarine, and occasionally freshwater habitat,
adjusting their foraging behavior to take advantage of prey that are
locally and seasonally abundant (Payne and Selzer, 1989). Research has
demonstrated that harbor seals conduct both shallow and deep dives
while foraging (Tollit et al., 1997), depending on prey availability.
Harbor seals usually give birth to a single pup between May and mid-
July; birthing locations are dispersed over several haulout sites and
not confined to major rookeries (Klinkhart et al., 2008). Harbor seals
haul out on rocks, reefs, beaches, and drifting glacial ice. They are
non-migratory; their local movements are associated with tides,
weather, season, food availability, and reproduction, as well as sex
and age class (Swain et al., 1996; Lowry et al., 2001; Boveng et al.,
2012).
Harbor seals are commonly sighted in the waters of the inside
passages throughout Southeast Alaska. They occur year-round within the
Project area and are regularly sighted in Auke Bay, including Statter
Harbor within Auke Bay. NOAA aerial survey data indicate that groups
ranging from 10 to 52 seals could be present within the Project area
during summer at haulouts on the western side of Coghlan Island, as
well as on Battleship Island (E. Richmond, pers. comm.). Harbor seals
were observed in all months of ADOT&PF's 2021 project in Auke Bay
(AKDOT&PF, 2021). Harbor seals are known to be curious and may approach
novel activity and could enter the Project area during pile
installation and removal.
Northern Elephant Seal
Northern elephant seals breed and give birth in California (U.S.)
and Baja California (Mexico), primarily on offshore islands, from
December to March (Stewart et al. 1994). Spatial segregation in
foraging areas between males and females is evident from satellite tag
data (Le Beouf et al., 2000). Males migrate to the Gulf of Alaska and
western Aleutian Islands along the continental shelf to feed on benthic
prey, while females migrate to pelagic areas in the Gulf of Alaska and
the central North Pacific to feed on pelagic prey (Le Beouf et al.,
2000).
Auke Bay is an unlikely area for an occurrence, as northern
elephant seals generally feed along the continental shelf break (Le
Boeuf et al., 2000) and are not expected to spend time in shallow
areas. No sightings of elephant seals have been documented near Auke
Bay; however, protected species observers (PSOs) at a ADOT&PF project
site in Ketchikan (460 kilometers south of Auke Bay) reported sightings
of a northern elephant seal on multiple days (C. Gentemann, pers.
comm., April 8, 2022). Additional sightings of northern elephant seals
around the state concurrent with the Ketchikan sighting were reported
in Seward, King Cove, and Kodiak (L. Davis, pers. comm., April 14,
2022). Breeding and important haulouts areas are not expected to
spatially overlap with the project area.
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. 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, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
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).
[[Page 22419]]
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.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take section later in this document includes a
quantitative analysis of the number of individuals that are expected to
be taken by this activity. The Negligible Impact Analysis and
Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and whether those
impacts are reasonably expected to, or reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.
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. 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 vibratory pile
removal. 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.,
aircraft, 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).
The likely or possible impacts of ADOT&PF'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.
Auditory Effects
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal is the primary means by which
marine mammals may be harassed from ADOT&PF'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). Exposure to pile driving
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 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
[[Page 22420]]
exposed for a long enough duration or to a high enough level to induce
a TS, the magnitude of the TS, time to recovery (seconds to minutes or
hours to days), the frequency range of the exposure (i.e., spectral
content), the hearing and vocalization frequency range of the exposed
species relative to the signal's frequency spectrum (i.e., how animal
uses sound within the frequency band of the signal; e.g., Kastelein et
al., 2014), and the overlap between the animal and the source (e.g.,
spatial, temporal, and spectral).
Permanent Threshold Shift (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 et
al., 2008). PTS levels for marine mammals are estimates, as 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
(2015), 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 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). 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 and
vibratory pile driving. 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 Effects
Exposure to noise from pile driving and removal 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. For a review of studies involving marine
mammal behavioral responses to sound, see Southall et al., 2007; Gomez
et al., 2016; and Southall et al., 2021 reviews.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known
[[Page 22421]]
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.
The area likely impacted by the project is relatively small
compared to the available habitat in the surrounding waters of Lynn
Canal. Although Auke Bay is part of an identified Biologically
Important Area for feeding humpback whales (Ferguson et al., 2015), the
timing of the BIA (March through November) only overlaps with the
proposed timing of the in-water construction (October through January)
for two months. Additionally, humpback foraging efforts within Auke Bay
itself are intermittent and irregular across seasons.
In 2021, ADOT&PF documented observations of marine mammals during
construction activities (i.e., pile driving) at the Auke Bay Ferry
Terminal (84 FR 56767, October 23, 2019). In the marine mammal
monitoring report for that project (State of Alaska, 2021), 30 Steller
sea lions were observed within the behavioral disturbance zone during
pile driving or drilling (i.e., documented as Level B harassment take).
Twenty eight harbor seals were observed within the disturbance zone
during pile driving activities. A lone Dall's porpoise was sighted in
the Level B harassment zone during construction. During the
construction activities six takes by Level B harassment of humpback
whales occurred. No signs of disturbance were noted for any of these
species that were present in the harassment zones. Given the
similarities in activities and habitat and the fact the same species
are involved, we expect similar behavioral responses of marine mammals
to the 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 projects have observed similar
behaviors.
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. Auke
Bay is home to a busy ferry terminal as well as moorage for small
private vessels that transit the area on a regular basis; therefore,
background sound levels in the harbor 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 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 exceeding the acoustic thresholds. We recognize that pinnipeds
in the water could be exposed to airborne sound that may result in
behavioral harassment when looking with their heads above water. Most
likely, airborne sound would cause behavioral responses similar to
those discussed above in relation to underwater sound. For instance,
anthropogenic sound could cause hauled-out pinnipeds to exhibit changes
in their normal behavior, such as reduction in vocalizations, or cause
them to temporarily abandon the area and move further from the source.
However, these animals would previously have been `taken' because of
exposure to underwater sound above the behavioral harassment
thresholds, which are in all cases larger than those associated with
airborne sound. Thus, the behavioral harassment of these animals is
already accounted for in these estimates of potential take. Therefore,
we do not believe that authorization of incidental take resulting from
airborne sound for pinnipeds is warranted, and airborne sound is not
discussed further here.
Marine Mammal Habitat Effects
ADOT&PF's construction activities could have localized, temporary
impacts on marine mammal habitat by increasing in-water sound pressure
levels and slightly decreasing water quality. Construction activities
are of short duration and would likely have temporary impacts on marine
mammal habitat through increases in underwater sound. Increased noise
levels may affect acoustic habitat (see masking discussion above) and
adversely affect marine mammal prey in the vicinity of the project area
(see discussion below). During pile driving, elevated levels of
underwater noise would ensonify Auke Bay where both fish and mammals
may occur and could affect foraging success.
In-water pile driving and pile removal would also cause short-term
effects on water quality due to increased turbidity. Local currents are
anticipated to disburse suspended sediments produced by project
activities at moderate to rapid rates depending on tidal stage. ADOT&PF
would employ standard construction best management practices, thereby
reducing any impacts. Considering the nature and duration of the
effects, combined with the measures to reduce turbidity, the impact
from increased turbidity levels is expected to be discountable.
Pile installation and removal may temporarily increase turbidity
resulting from suspended sediments. Any increases would be temporary,
localized, and minimal. ADOT&PF must comply with state water quality
standards during these operations by limiting the extent of turbidity
to the immediate project area. In general, turbidity associated with
pile installation is localized to about a 25-foot radius around the
pile (Everitt et al. 1980). Cetaceans are not expected to enter the
harbor and be close enough to the project pile driving areas to
[[Page 22422]]
experience effects of turbidity, and any pinnipeds would likely 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.
Effects on Prey
Construction activities would produce continuous (i.e., vibratory
pile driving) and impulsive (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 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.
Impacts on marine mammal prey (i.e., fish or invertebrates) of the
immediate area due to the acoustic disturbance are possible. The
duration of fish or invertebrate avoidance or other disruption of
behavioral patterns in this area after pile driving stops is unknown,
but a rapid return to normal recruitment, distribution and behavior is
anticipated. Further, significantly large areas of fish and marine
mammal foraging habitat are available in the nearby vicinity in Lynn
Canal.
The duration of the construction activities is relatively short,
with pile driving and removal activities expected to take only 61 days.
Each day, construction would occur for no more than 12 hours during the
day and pile driving activities would be restricted to daylight hours.
The most likely impact to fish from pile driving activities at the
project area would be temporary behavioral avoidance of the area. In
general, impacts to marine mammal prey species are expected to be minor
and temporary due to the short timeframe for the project.
Construction activities, in the form of increased turbidity, have
the potential to adversely affect fish in the project area. Increased
turbidity is expected to occur in the immediate vicinity (on the order
of 10 feet (3 meters) 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 fish 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.
In summary, given the short daily duration of sound associated with
individual pile driving and events and the relatively small areas being
affected, pile driving 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 would inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Authorized takes would primarily be by Level B harassment,
as use of the acoustic sources (i.e., impact and vibratory pile
driving) has the potential to result in disruption of behavioral
patterns for individual marine mammals. There is also some potential
for auditory injury (Level A harassment) to result, primarily for high
frequency cetaceans and phocids because predicted auditory injury zones
are larger than for other hearing groups. Auditory injury is unlikely
to occur for other groups. The proposed mitigation and monitoring
measures are expected to minimize the severity of the taking to the
extent practicable.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals would be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that would be ensonified above these levels in
a day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment).
Level B Harassment--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 or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (root mean square (RMS) SPL) of
120 dB (referenced to 1 micropascal (re 1 microPascal ([mu]Pa)) for
continuous (e.g., vibratory pile-driving) and above RMS SPL 160 dB re 1
[mu]Pa for non-explosive impulsive (e.g., seismic airguns, impact pile
driving) or intermittent (e.g., scientific sonar) sources. Generally
speaking, Level B harassment take estimates based on these behavioral
harassment thresholds are expected to include any likely takes by TTS
as, in most cases, the likelihood of TTS occurs
[[Page 22423]]
at distances from the source less than those at which behavioral
harassment is likely. TTS of a sufficient degree can manifest as
behavioral harassment, as reduced hearing sensitivity and the potential
reduced opportunities to detect important signals (conspecific
communication, predators, prey) may result in changes in behavior
patterns that would not otherwise occur.
ADOT&PF's proposed activity includes the use of continuous
(vibratory pile driving and removal) and impulsive (impact pile
driving) sources, and therefore the RMS SPL thresholds of 120 and 160
dB re 1 [mu]Pa are applicable.
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise from
two different types of sources (impulsive or non-impulsive). ADOT&PF's
proposed activity includes the use of impulsive (impact pile driving)
and non-impulsive (vibratory pile driving and removal) sources.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 4--Onset of Permanent Threshold Shift (PTS)
[NMFS 2018]
----------------------------------------------------------------------------------------------------------------
PTS onset thresholds * (received level)
Hearing group -------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans.......... Cell 1: L0-pk,flat: 219 Cell 2: LE,, LF,24h: 199 dB.
dB; LE, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans.......... Cell 3: L0-pk,flat: 230 Cell 4: LE,, MF,24h: 198 dB.
dB; LE, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans......... Cell 5: L0-pk,flat: 202 Cell 6: LE,, HF,24h: 173 dB.
dB; LE,,HF,24h: 155 dB.
Phocid Pinnipeds (PW)(Underwater)..... Cell 7: L0-pk.flat: 218 Cell 8: LE,PW,24h: 201 dB.
dB; LE,,PW,24h: 185 dB.
Otariid Pinnipeds (OW)(Underwater).... Cell 9: L0-pk,flat: 232 Cell 10: LE,OW,24h: 219 dB.
dB; LE,,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
exposure level (LE,) has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
hearing range of marine mammals (i.e., 7 Hz to 160 kHz). 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 weighted
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 thresholds will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including 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 and removal). The maximum (underwater) area ensonified
above the thresholds for behavioral harassment referenced above is
11.49 km\2\ (7.14 mi\2\), and is governed by the topography of Auke Bay
and the various islands located within and around the bay. The eastern
part of Auke Bay is acoustically shadowed by Auke Cape. Coghlan Island,
and Suedla Island, and would inhibit sound transmission from reaching
the more open waters toward Spuhn Island (see Figure 6-2 in the IHA
application). Additionally, vessel traffic and other commercial and
industrial activities in the project area may contribute to elevated
background noise levels which may mask sounds produced by the project.
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
R1 = the distance of the modeled SPL from the driven
pile, and
R2 = the distance from the driven pile of the initial
measurement
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log[range]). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting in a reduction of 3 dB in sound level
for each doubling of distance from the source (10*log[range]). A
practical spreading value of 15 is often used under conditions, such as
the project site, where water increases with depth as the receiver
moves away from the shoreline, resulting in an expected propagation
environment that would lie between spherical and cylindrical spreading
loss conditions. Practical spreading loss is assumed here.
The intensity of pile driving sounds is greatly influenced by
factors such as the type of piles, hammers, and the physical
environment in which the activity takes place. In order to calculate
the distances to the Level A harassment and the Level B harassment
sound thresholds for the methods and piles being used in this
[[Page 22424]]
project, NMFS used acoustic monitoring data from other locations to
develop proxy source levels for the various pile types, sizes and
methods. The project includes vibratory and impact pile installation of
steel pipe piles and vibratory removal of steel pipe piles. Source
levels for each pile size and driving method are presented in Table 5.
The source levels for vibratory and impact installation of all pile
sizes are based on the averaged source level of the same type of pile
reported by California Department of Transportation (Caltrans) in pile
driving source level compendium documents (Caltrans, 2015 and 2020).
Table 5--Proxy Sound Source Levels for Pile Sizes and Driving Methods
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proxy source level
------------------------------------------------
Pile size Method dB RMS re dB SEL re dB peak re Literature source
1[mu]Pa 1[mu]Pa\2\sec 1[mu]Pa
--------------------------------------------------------------------------------------------------------------------------------------------------------
30 in............................... Vibratory.............. 159 N/A N/A Caltrans 2020.
24 in............................... Vibratory.............. 154 N/A N/A Caltrans 2020.
18 in............................... Vibratory.............. 158 N/A N/A Caltrans 2020.
30 in............................... Impact................. 190 177 210 Caltrans 2015, 2020.
24 in............................... Impact................. 190 177 203 Caltrans 2015, 2020.
18 in............................... Impact................. 185 175 200 Caltrans 2015, 2020.
--------------------------------------------------------------------------------------------------------------------------------------------------------
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the Technical Guidance that can be used
to relatively simply predict an isopleth distance for use in
conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources such as impact or vibratory pile driving and
removal, the optional User Spreadsheet tool predicts the distance at
which, if a marine mammal remained at that distance for the duration of
the activity, it would be expected to incur PTS. Inputs used in the
optional User Spreadsheet tool (Table 6), and the resulting estimated
isopleths and the calculated Level B harassment isopleth (Table 7), are
reported below. For source levels of each pile please refer to Table 5.
For impact installation of piles the harassment zones were
calculated based on the number of piles to be installed per day.
ADOT&PF provided a range of one to four piles per day for impact
instillation for all pile sizes. This was done to account for more
efficient days of pile installation as not to limit construction
activity on those days. If more piles per day are installed it is
likely to reduce the number of days impact installation would occur.
Table 6--User Spreadsheet Input Parameters Used for Calculating Level A Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
Weighting
factor Number of Number of Activity
Pile size and installation method Spreadsheet tab used adjustment strikes per piles per duration
(kHz) pile day (minutes)
----------------------------------------------------------------------------------------------------------------
30 in vibratory installation........ A.1 Vibratory pile 2.5 N/A 3 60
driving.
24 in vibratory installation........ A.1 Vibratory pile 2.5 N/A 3 60
driving.
24 in vibratory installation A.1 Vibratory pile 2.5 N/A 3 30
(temporary). driving.
24 in vibratory removal (temporary). A.1 Vibratory pile 2.5 N/A 3 60
driving.
18 in vibratory installation........ A.1 Vibratory pile 2.5 N/A 3 60
driving.
18 in vibratory removal (existing).. A.1 Vibratory pile 2.5 N/A 3 30
driving.
30 in impact installation........... E.1 Impact pile 2 1,000 1-4 N/A
driving.
24 in impact installation........... E.1 Impact pile 2 1,000 1-4 N/A
driving.
24 in impact installation........... E.1 Impact pile 2 500 1-4 N/A
driving.
18 in impact installation........... E.1 Impact pile 2 800 1-4 N/A
driving.
----------------------------------------------------------------------------------------------------------------
Table 7-- Calculated Level A and Level B Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
Level A harassment zone (m)
--------------------------------------------------------- Level B
Activity LF- MF- HF- harassment
cetaceans cetaceans cetaceans Phocids Otariids zone (m)
----------------------------------------------------------------------------------------------------------------
30 in vibratory installation.............. 11 1 16 7 1 3,981
24 in vibratory installation.............. 5 1 8 3 1 1,848
24 in vibratory installation (temporary).. 4 1 5 2 1 ...........
18 in vibratory installation.............. 9 1 14 6 1 ...........
24 in vibratory removal (temporary)....... 5 1 8 3 1 ...........
18 in vibratory removal (existing)........ 9 1 14 6 1 ...........
30 in impact installation (4 piles per 1,002 36 1,194 537 39 1,000
day; 1,000 strikes per pile).............
30 in impact installation (3 piles per 827 30 985 443 33 ...........
day; 1,000 strikes per pile).............
30 in impact installation (2 piles per 632 23 752 338 25 ...........
day; 1,000 strikes per pile).............
[[Page 22425]]
30 in impact installation (1 pile per day; 398 15 474 213 16
1,000 strikes per pile)..................
24 in impact installation (4 piles per 1,002 36 1,194 537 39 1,000
day; 1,000 strikes per pile).............
24 in impact installation (3 piles per 827 30 985 443 33 ...........
day; 1,000 strikes per pile).............
24 in impact installation (2 piles per 632 23 752 338 25 ...........
day; 1,000 strikes per pile).............
24 in impact installation (1 pile per day; 398 15 474 213 16 ...........
1,000 strikes per pile)..................
24 in impact installation (4 piles per 632 23 752 338 25 ...........
day; 500 strikes per pile)...............
24 in impact installation (3 piles per 521 19 621 279 21 ...........
day; 500 strikes per pile)...............
24 in impact installation (2 piles per 398 15 474 213 16 ...........
day; 500 strikes per pile)...............
24 in impact installation (1 pile per day; 251 9 299 134 10 ...........
500 strikes per pile)....................
18 in impact installation (4 piles per 636 23 757 340 25 464
day; 800 strikes per pile)...............
18 in impact installation (3 piles per 525 19 625 281 21 ...........
day; 800 strikes per pile)...............
18 in impact installation (2 piles per 401 15 477 215 16 ...........
day; 800 strikes per pile)...............
18 in impact installation (1 pile per day; 252 9 301 135 10 ...........
800 strikes per pile)....................
----------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence and Take Estimation
In this section, we provide information about the occurrence of
marine mammals, including density or other relevant information that
would inform the take calculations.
When available, peer-reviewed scientific publications were used to
estimate marine mammal abundance in the project area. Data from
monitoring reports from previous projects on the Auke Bay Ferry
Terminal were used as well as reports from other projects in Juneau,
Alaska. However, scientific surveys and resulting data, such as
population estimates, densities, and other quantitative information,
are lacking for some marine mammal populations and most areas of
southeast Alaska, including Auke Bay. Therefore, AKDOT&PF gathered
qualitative information from discussions with knowledgeable local
people in the Auke Bay area.
Here we describe how the information provided is synthesized to
produce a quantitative estimate of the take that is reasonably likely
to occur and proposed for authorization. Since reliable densities are
not available, the applicant requests take based on the maximum number
of animals that may occur in the harbor in a specified measure of time
multiplied by the total duration of the activity.
Humpback Whale
Use of Auke Bay by humpback whales is intermittent and irregular
year-round. During winter, researchers have documented 1 to 19
individual humpback whales per month in waters close to the project
area, including Lynn Canal (Moran et al., 2018a; Straley et al., 2018).
Group sizes in southeast Alaska generally range from one to four
individuals (Dahlheim et al., 2009). Based on this, we predict that two
groups of two humpback whales could be exposed to Level B harassment
during each day of the 61 days of work for a total of 244 animals. As
described previously, 2.4 percent of the humpback whales in Southeast
Alaska are members of the Mexico DPS, and therefore six animals would
be Mexico DPS individuals and the remaining 238 animals would be Hawaii
DPS individuals.
The largest Level A shutdown zone for humpback whales extends 1,002
meters from the noise source (Table 7), and would occur only on days
when impact driving of four piles is expected. All construction work
would be shut down prior to a humpback whale entering the Level A zone
specific to the in-water activity underway at the time. No take by
Level A harassment is proposed or requested for humpback whales.
Minke Whales
Dedicated surveys for cetaceans in southeast Alaska found that
minke whales were scattered throughout inland waters from Glacier Bay
and Icy Strait to Clarence Strait, with small concentrations near the
entrance of Glacier Bay. All sightings were of single minke whales,
except for a single sighting of multiple minke whales. Surveys took
place in spring, summer, and fall, and minke whales were present in low
numbers in all seasons and years (Dahlheim et al., 2009). Although
minke whales are rarely occur in the project area we are conservatively
proposing to authorize take of one minke whale per month by Level B
harassment.
The Level A harassment zones for minke whales are the same as for
humpback whales, and the shutdown protocols would be the same as well.
Therefore, given the low occurrence of minke whales combined with the
mitigation, takes by Level A harassment have not been requested and are
not proposed to be authorized.
Killer Whale
Killer whales are observed occasionally during summer throughout
Lynn Canal, but their presence in Auke Bay is unlikely. As a
precaution, because Level B harassment zones extend beyond Auke Bay,
ADOT&PF requests take by Level B harassment for one killer whale
resident pod and one transient pod. Groups from those pods are likely
to be 14 animals and 44 animals, respectively (Dahlheim et al., 2009).
ADOT&PF would implement shutdown zones that encompass the largest Level
A harassment zones for killer whales during all pile driving
activities. Killer whales are generally conspicuous and PSOs are
expected to detect killer whales and implement a shutdown before the
animals enter the Level A harassment zone. Therefore, takes by Level A
harassment have not been requested and are not proposed to be
authorized.
Pacific White-Sided Dolphins
Based on occurrence data ADOT&PF requested a total of 92 takes by
Level B harassment (the median group size observed in aerial surveys;
range from 20 to 164 individuals) (Muto et al. 2022). NMFS concurs and
has proposed authorization of Level B harassment of one group of
Pacific white-sided dolphins to occur over the duration of the project.
The largest Level A harassment zone for Pacific white-sided dolphins
extends 36 m from the source during impact installation of 30-in piles
(Table 7). Pacific white-sided dolphins are expected to be seen by PSOs
before entering this zone and shutdown of activity would occur. No take
by Level
[[Page 22426]]
A harassment is proposed or anticipated.
Harbor Porpoise
Initially ADOT&PF requested a total of 122 takes of harbor porpoise
over the course of the 61 day project. ADOT&PF estimated that 25
percent of those takes could be Level A exposures which would equate to
30 over the project duration. After further review of current and
previous monitoring results, including unpublished data (Wright, S.,
pers. comm.), that showed higher numbers of harbor porpoises in the
area, we recommended four animals per day equating to 244 takes of
harbor porpoise by Level A and Level B harassment. NMFS predicts that
up to 25 percent of the total exposures could result in take by Level A
harassment for a total of 61. The remaining 183 takes would be by Level
B harassment.
Harbor porpoises are known to be an inconspicuous species and are
challenging for protected species observers (PSOs) to sight, making any
approach to a specific area potentially difficult to detect. Because
harbor porpoises move quickly and elusively, it is possible that they
may enter the Level A harassment zone without detection. The largest
Level A harassment zone results from impact driving of 30-in piles, and
extends 1,194 m from the source for high frequency cetaceans (Table 7).
ADOT&PF would implement a shutdown zone for harbor porpoises that
encompasses the largest Level A harassment zone (see Proposed
Mitigation section) but given the sighting challenges for PSOs some
take by Level A harassment is expected.
Dall's Porpoise
No systematic studies of Dall's porpoise abundance or distribution
have occurred in Auke Bay; however, Dall's porpoises have been
consistently observed in Lynn Canal, Stephens Passage, upper Chatham
Strait, Frederick Sound, and Clarence Strait (Dalheim et al., 2000).
ADOT&PF initially requested take of one group of 20 animals per month
in the project area for a total of 80 takes by Level B harassment.
After reviewing ADOT&PF's monitoring results from Auke Bay one lone
Dall's porpoise was sighted. Thus, we proposed a conservative estimate
of two groups of five animals per month. This would result in a maximum
of 30 takes by Level B harassment throughout the course of the project.
ADOT&PF would implement shutdown zones for porpoises that encompass
the largest Level A harassment zones for each pile driving activity
(see Proposed Mitigation section). The largest Level A harassment zone
for Dall's porpoise extends 1,194 m from the source during impact
installation of 30-in piles (Table 7). Given the more conspicuous
rooster-tail generated by swimming Dall's porpoises, which makes them
more noticeable than harbor porpoises, PSOs are expected to detect
Dall's porpoises prior to them entering the Level A harassment zone
(Jefferson 2009). Therefore, takes of Dall's porpoises by Level A
harassment have not been requested and are not proposed to be
authorized.
Steller Sea Lion
Based on recent monitoring reports for Auke Bay Ferry Terminal and
Statter Harbor projects it is estimated that groups of up to 50 animals
per day could be exposed to underwater noise. A total of 3,050
exposures to sound levels at or above the Level B harassment threshold
could occur over the 61 days of construction. Given the 1.4 percent of
Steller sea lions belong to the wDPS in Auke Bay, 43 total exposures
are expected from the wDPS and the remaining 3,008 exposures of eDPS
Steller sea lions.
The largest Level A harassment zone for otariid pinnipeds extends
39 m from the source (Table 7). ADOT&PF is planning to implement a
larger shutdown zones than the Level A harassment zones during all pile
installation and removal activities (see Proposed Mitigation section),
which is expected to eliminate the potential for take by Level A
harassment of Steller sea lions. Therefore, no takes of Steller sea
lions by Level A harassment were requested or are proposed to be
authorized.
California Sea Lion
California sea lions rarely occur in the project area. In 2017, a
lone California sea lion was spotted in the harbor. Recently,
monitoring reports from similar construction projects did not observe
any California sea lions in Auke Bay. Based on the sighting from 2017,
ADOT&PF is estimating one animal per day of construction which would
equate to 61 takes by Level B harassment.
Similar to Steller sea lions, the largest Level A harassment zone
for otariid pinnipeds extends 39 m from the source (Table 7). ADOT&PF
is planning to implement larger shutdown zones than the Level A
harassment zones during all pile installation and removal activities
(see Proposed Mitigation section), which is expected to eliminate the
potential for take by Level A harassment of California sea lions.
Therefore, no takes of California sea lions by Level A harassment were
requested or are proposed to be authorized.
Northern Fur Seal
Although take of Northern fur seal was not requested by ADOT&PF,
the NMFS Alaska Regional Office recommended the inclusion of Northern
fur seals in the take estimation. We estimate that five northern fur
seals may be present in the action area per month which would result in
15 takes by Level B harassment over the course of the project.
The largest Level A harassment zone for otariid pinnipeds extends
39 m from the source (Table 7). ADOT&PF is planning to implement larger
shutdown zones than the Level A harassment zones during all pile
installation and removal activities (see Proposed Mitigation section),
which is expected to eliminate the potential for take by Level A
harassment of Northern fur seals. Therefore, no takes of Northern fur
seals by Level A harassment were requested or are proposed to be
authorized.
Harbor Seal
Based on monitoring results of ADOT&PF's 2021 project in Auke Bay
it is expected that 50 harbor seals per day could be taken during the
61 days of construction (AKDOT&PF, 2021). This would equate to 3,050
takes of harbor seals by Level B harassment during the duration of the
project.
The largest Level A harassment zone for phocid pinnipeds results
from impact pile driving of 30-in piles and extends 537 m from the
source (Table 7). There are no haulouts located within the Level A
harassment zone and although it is unlikely that harbor seals would
enter this area without detection while pile driving activities are
underway, it is possible that harbor seals may approach and enter the
Level A harassment zone undetected. Two harbor seals are estimated to
approach the site within 537 m of the source each day. Impact pile
driving may occur on up to 34 days (Table 1). For this reason, we
propose take by Level A harassment of two harbor seals daily on the 34
days of impact pile driving for a total of 68 takes by Level A
harassment. The largest Level A harassment zone for phocid pinnipeds
from vibratory pile driving extends 30 m from the source (Table 7).
ADOT&PF is planning to implement larger shutdown zones than the Level A
harassment zones during all pile installation and removal activities
(see Proposed Mitigation section), which is expected to eliminate the
potential for
[[Page 22427]]
Level A harassment of harbor seals from vibratory pile driving.
Northern Elephant Seal
Given the increase in population size and sightings throughout
Southeast Alaska ADOT&PF requested one elephant seal take per week. The
project is expected to take up to 16 weeks to complete which would
equate to 16 takes by Level B harassment.
The largest Level A harassment zone for phocid pinnipeds extends
537 m from the source (Table 7). ADOT&PF is planning to implement
larger shutdown zones than the Level A harassment zones during all pile
installation and removal activities (see Proposed Mitigation section),
which is expected to eliminate the potential for take by Level A
harassment of elephant seals. Therefore, no takes of elephant seals by
Level A harassment were requested or are proposed to be authorized.
Table 8--Estimated Take by Level A and Level B Harassment, by Species and Stock
----------------------------------------------------------------------------------------------------------------
Proposed
Stock Total take as
Common name Stock abundance \a\ Level A Level B proposed percentage
take of stock
----------------------------------------------------------------------------------------------------------------
Humpback whale.................. Central North 10,103 0 \b\ 244 244 2.4
Pacific.
Minke whale..................... Alaska............ N/A 0 4 4 N/A
Killer Whale.................... Alaska Resident... 1,920 0 41 41 2.1
West Coast 349 0 14 14 4.0
Transient.
Pacific white-sided dolphin..... North Pacific..... 931,000 0 92 92 <0.01
Harbor porpoise................. Southern Southeast 890 61 183 244 27.4
Alaska Inland
Waters.
Dall's porpoise................. Alaska............ 83,400 0 30 30 0.03
Steller sea lion................ Eastern U.S....... 43,201 0 3,008 3,008 6.9
Western U.S....... 52,932 0 43 43 0.08
California sea lion............. U.S............... 257,606 0 61 61 0.02
Northern fur seal............... Eastern Pacific... 626,618 0 15 15 <0.01
Harbor seal..................... Lynn Canal/ 13,388 68 2,982 3,050 22.8
Stephens Passage.
Northern Elephant Seal.......... California........ 187,386 0 16 16 <0.01
----------------------------------------------------------------------------------------------------------------
\a\ Stock or DPS size is Nbest according to NMFS 2022 Draft Stock Assessment Reports.
\b\ For ESA section 7 consultation purposes, 2.4 percent are designated to the Mexico DPS and the remaining are
designated to the Hawaii DPS; therefore, we assigned 6 takes by Level B harassment to the Mexico DPS.
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. 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, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure would 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.
In addition to the measures described later in this section,
ADOT&PF would employ the following standard mitigation measures:
At the start of each day, the Contractor(s) would hold a
briefing with the Lead PSO to outline the activities planned for that
day.
If poor weather conditions restrict the PSO's ability to
make observations within the Level A and B harassment zone of pile
driving (e.g., if there is excessive wind or fog), pile installation
and removal would be halted.
The following measures would apply to ADOT&PF's mitigation
requirements:
Implementation of Shutdown Zones for Level A Harassment--For all
pile driving/removal activities, ADOT&PF would implement shutdowns
within designated zones. The purpose of a shutdown zone is generally to
define an area within which shutdown of activity would occur upon
sighting of a marine mammal (or in anticipation of an animal entering
the defined area). Implementation of shutdowns would be used to avoid
or minimize incidental Level A harassment exposures from vibratory and
impact pile driving for all 11 species for which take may occur (see
Table 8). ADOT&PF has voluntarily implemented a minimum shutdown zone
of 30 m during all pile driving and removal activities (Table 9).
Shutdown zones for impact pile driving activities are based on the
Level A harassment zones and therefore vary by pile size, number of
piles installed per day, and marine mammal hearing group (Table 9).
Shutdown zones for impact pile driving would be established each day
for the greatest number of piles that are expected to be installed that
day. The placement of PSOs during all pile driving activities
(described in detail in the Monitoring and Reporting section) would
ensure the full extent of shutdown zones are visible to PSOs.
[[Page 22428]]
Table 9--Shutdown Zones During Pile Installation and Removal
----------------------------------------------------------------------------------------------------------------
Shutdown zones (m)
Piles per --------------------------------------------------------
Activity day * LF MF HF
cetaceans cetaceans cetaceans Phocids Otariids
----------------------------------------------------------------------------------------------------------------
All vibratory installation and removal..... 30
----------------------------------------------------------------------------------------------------------------
30-in impact (1,000 strikes)............... 4 1,100 40 1,200 540 40
3 830 30 990 450 .........
2 640 760 340 30
1 400 480 220
----------------------------------------------------------------------------------------------------------------
24-in impact (1,000 strikes)............... 4 1,100 40 1,200 540 40
3 830 30 990 450 30
2 640 .......... 760 340
1 400 .......... 480 220
----------------------------------------------------------------------------------------------------------------
24-in impact (500 strikes)................. 4 640 30 760 340 30
3 530 630 280
2 400 480 220
1 260 300 140
----------------------------------------------------------------------------------------------------------------
18-in impact (800 strikes)................. 4 640 30 760 340 30
3 530 630 280
2 400 480 220
1 260 300 140
----------------------------------------------------------------------------------------------------------------
* The applicant would chose the number of piles to be driven in any given day before work begins
Establishment of Monitoring Zones--ADOT&PF has identified
monitoring zones correlated with the larger of the Level B harassment
or Level A harassment zones. Monitoring zones provide utility for
observing by establishing monitoring protocols for areas adjacent to
the shutdown zones. Monitoring zones enable observers to be aware of
and communicate the presence of marine mammals in the project area
outside the shutdown zone and thus prepare for a potential cease of
activity should the animal enter the shutdown zone. PSOs would monitor
the entire visible area to maintain the best sense of where animals are
moving relative to the zone boundaries defined in Tables 9 and 10.
Placement of PSOs on the shorelines around Auke Bay allow PSOs to
observe marine mammals within and near Auke Bay.
Table 10--Marine Mammal Monitoring Zone
------------------------------------------------------------------------
Monitoring zone
Activity (m)
------------------------------------------------------------------------
30-in vibratory installation......................... 3,981
24-in and 18-in vibratory installation and removal... 1,848
30-in and 24 in impact installation.................. 1,200
18-in impact installation............................ 760
------------------------------------------------------------------------
Soft Start--The use of soft-start procedures are believed to
provide additional protection to marine mammals by providing warning
and/or giving marine mammals a chance to leave the area prior to the
hammer operating at full capacity. For impact pile driving, contractors
would be required to provide an initial set of strikes from the hammer
at reduced energy, with each strike followed by a 30-second waiting
period. This procedure would be conducted a total of three times before
impact pile driving begins. Soft start would be implemented at the
start of each day's impact pile driving and at any time following
cessation of impact pile driving for a period of 30 minutes or longer.
Soft start is not required during vibratory pile driving and removal
activities.
Pre-Activity Monitoring--Prior to the start of daily in-water
construction activity, or whenever a break in pile driving/removal of
30 minutes or longer occurs, PSOs would observe the shutdown and
monitoring zones for a period of 30 minutes. The shutdown zone would be
considered cleared when a marine mammal has not been observed within
the zone for that 30-minute period. If a marine mammal is observed
within the shutdown zone, a soft-start cannot proceed until the animal
has left the zone or has not been observed for 15 minutes. If the
monitoring zone has been observed for 30 minutes and marine mammals are
not present within the zone, soft-start procedures can commence and
work can continue even if visibility becomes impaired within the
monitoring zone. When a marine mammal permitted for take by Level B
harassment is present in the Level B harassment zone, activities may
begin. No work may begin unless the entire shutdown zone is visible to
the PSOs. If work ceases for more than 30 minutes, the pre-activity
monitoring of both the monitoring zone and shutdown zone would
commence.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries,
[[Page 22429]]
mating grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that would 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 while
conducting the activities. 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 activity; 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 shall be conducted by NMFS-approved observers in
accordance with the monitoring plan and section 5 of the IHA. Trained
observers shall be placed from the best vantage point(s) practicable to
monitor for marine mammals and implement shutdown or delay procedures
when applicable through communication with the equipment operator.
Observer training must be provided prior to project start, and shall
include instruction on species identification (sufficient to
distinguish the species in the project area), description and
categorization of observed behaviors and interpretation of behaviors
that may be construed as being reactions to the specified activity,
proper completion of data forms, and other basic components of
biological monitoring, including tracking of observed animals or groups
of animals such that repeat sound exposures may be attributed to
individuals (to the extent possible).
Monitoring would be conducted 30 minutes before, during, and 30
minutes after pile driving/removal activities. In addition, observers
shall record all incidents of marine mammal occurrence, regardless of
distance from activity, and shall document any behavioral reactions in
concert with distance from piles being driven or removed. Pile driving/
removal activities include the time to install or remove a single pile
or series of piles, as long as the time elapsed between uses of the
pile driving equipment is no more than 30 minutes.
A minimum of two PSOs would be on duty during all impact
installation and a minimum of three MMOs during vibratory installation/
removal. Locations from which MMOs would be able to monitor for marine
mammals are readily available from publicly accessible shoreside areas
at the Auke Bay East Ferry Terminal and, if necessary, other public and
private points along the Glacier and Douglas highways. Monitoring
locations would be selected by the Contractor during pre-construction.
PSOs would monitor for marine mammals entering the Level B harassment
zones; the position(s) may vary based on construction activity and
location of piles or equipment.
PSOs would scan the waters using binoculars, and/or spotting
scopes, and would use a handheld range-finder device to verify the
distance to each sighting from the project site. All PSOs would be
trained in marine mammal identification and behaviors and are required
to have no other project-related tasks while conducting monitoring. In
addition, monitoring would be conducted by qualified observers, who
would 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 via a radio. ADOT&PF
would adhere to the following observer qualifications:
(i) Independent observers (i.e., not construction personnel) are
required;
(ii) One PSO would be designated as the lead PSO or monitoring
coordinator and that observer must have prior experience working as an
observer;
(iii) Other observers may substitute education (degree in
biological science or related field) or training for experience; and
(iv) ADOT&PF must submit observer Curriculum Vitaes for approval by
NMFS.
Additional standard observer qualifications include:
Ability to conduct field observations and collect data
according to assigned protocols;
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates and times when in-water construction
activities were suspended to avoid potential incidental injury from
construction sound of marine mammals observed within a defined shutdown
zone; and marine mammal behavior; and
Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Reporting
A draft marine mammal monitoring report would be submitted to NMFS
within 90 days after the completion of pile driving and removal
activities. It would include an overall description of work completed,
a narrative regarding marine mammal sightings, and associated PSO 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 the number and type of piles driven or
removed and by what method (i.e., impact driving) and the total
equipment duration for cutting for each pile or total number of strikes
for each pile (impact driving).
[[Page 22430]]
PSO locations during marine mammal monitoring.
Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
Upon observation of a marine mammal, the following
information: Name of PSO who sighted the animal(s) and PSO location and
activity at time of sighting; Time of sighting; Identification of the
animal(s) (e.g., genus/species, lowest possible taxonomic level, or
unidentified), PSO confidence in identification, and the composition of
the group if there is a mix of species; Distance and bearing of each
marine mammal observed relative to the pile being driven for each
sighting (if pile driving was occurring at time of sighting); Estimated
number of animals (min/max/best estimate); Estimated number of animals
by cohort (adults, juveniles, neonates, group composition, etc.);
Animal's closest point of approach and estimated time spent within the
harassment zone; Description of any marine mammal behavioral
observations (e.g., observed behaviors such as feeding or traveling),
including an assessment of behavioral responses thought to have
resulted from the activity (e.g., no response or changes in behavioral
state such as ceasing feeding, changing direction, flushing, or
breaching);
Number of marine mammals detected within the harassment
zones, by species.
Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting changes in behavior of the
animal(s), if any.
If no comments are received from NMFS within 30 days, the draft
final report would 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 unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by the IHA
(if issued), such as an injury, serious injury or mortality, ADOT&PF
would immediately cease the specified activities and report the
incident to the Chief of the Permits and Conservation Division, Office
of Protected Resources, NMFS, and the Alaska Regional Stranding
Coordinator. The report would include the following information:
Description of the incident;
Environmental conditions (e.g., Beaufort sea state,
visibility);
Description of all marine mammal observations in the 24
hours preceding the incident;
Species identification or description of the animal(s)
involved;
Fate of the animal(s); and
Photographs or video footage of the animal(s) (if
equipment is available).
Activities would not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS would work with ADOT&PF to
determine what is necessary to minimize the likelihood of further
prohibited take and ensure MMPA compliance. ADOT&PF would not be able
to resume their activities until notified by NMFS via letter, email, or
telephone.
In the event that ADOT&PF discovers an injured or dead marine
mammal, and the lead PSO determines that the cause of the injury or
death is unknown and the death is relatively recent (e.g., in less than
a moderate state of decomposition as described in the next paragraph),
ADOT&PF would immediately report the incident to the Chief of the
Permits and Conservation Division, Office of Protected Resources, NMFS,
and the NMFS Alaska Stranding Hotline and/or by email to the Alaska
Regional Stranding Coordinator. The report would include the same
information identified in the paragraph above. Activities would be able
to continue while NMFS reviews the circumstances of the incident. NMFS
would work with ADOT&PF to determine whether modifications in the
activities are appropriate.
In the event that ADOT&PF discovers an injured or dead marine
mammal and the lead PSO determines that the injury or death is not
associated with or related to the activities authorized in the IHA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), ADOT&PF would report the incident
to the Chief of the Permits and Conservation Division, Office of
Protected Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or
by email to the Alaska Regional Stranding Coordinator, within 24 hours
of the discovery. ADOT&PF would provide photographs, video footage (if
available), or other documentation of the stranded animal sighting to
NMFS and the Marine Mammal Stranding Network.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), 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' 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 baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the majority of our analysis applies to all
the species listed in Table 8, given that many of the anticipated
effects of this project on different marine mammal stocks are expected
to be relatively similar in nature. Where there are meaningful
differences between species or stocks, or groups of species, in
anticipated individual responses to activities, impact of expected take
on the population due to differences in population status, or impacts
on habitat, they are described independently in the analysis below.
Pile driving and removal activities associated with the project as
outlined previously, have the potential to disturb or displace marine
mammals. Specifically, the specified 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. Potential takes could
occur if individuals of these
[[Page 22431]]
species are present in zones ensonified above the thresholds for Level
A or Level B harassment identified above when these activities are
underway.
Take by Level A and Level B harassment would be due to potential
behavioral disturbance, TTS, and PTS. No serious injury or mortality is
anticipated or proposed for authorization given the nature of the
activity and measures designed to minimize the possibility of injury to
marine mammals. Take by Level A harassment is only anticipated for
harbor porpoise and harbor seal. The potential for harassment is
minimized through the construction method and the implementation of the
planned mitigation measures (see Proposed Mitigation section).
Based on reports in the literature as well as monitoring from other
similar activities, behavioral disturbance (i.e., level B harassment)
would likely be limited to reactions such as increased swimming speeds,
increased surfacing time, or decreased foraging (if such activity were
occurring) (e.g., Thorson and Reyff, 2006; HDR, Inc. 2012; Lerma, 2014;
ABR, 2016). Most likely for pile driving, individuals would simply move
away from the sound source and be temporarily displaced from the areas
of pile driving, although even this reaction has been observed
primarily only in association with impact pile driving. The pile
driving activities analyzed here are similar to, or less impactful
than, numerous other construction activities conducted in southeast
Alaska, which have taken place with no observed severe responses of any
individuals or known long-term adverse consequences. Level B harassment
would be reduced to the level of least practicable adverse impact
through use of mitigation measures described herein and, if sound
produced by project activities is sufficiently disturbing, animals are
likely to simply avoid the area while the activity is occurring. While
vibratory driving associated with the proposed project may produce
sound at distances of many kilometers from the project site, thus
overlapping with some likely less-disturbed habitat, the project site
itself is located in a busy harbor and the majority of sound fields
produced by the specified activities are close to the harbor. Animals
disturbed by project sound would be expected to avoid the area and use
nearby higher-quality habitats.
In addition to the expected effects resulting from authorized Level
B harassment, we anticipate that harbor porpoises and harbor seals may
sustain some limited Level A harassment in the form of auditory injury.
However, animals in these locations that experience PTS would likely
only receive slight PTS, i.e. minor degradation of hearing capabilities
within regions of hearing that align most completely with the energy
produced by pile driving, i.e. the low-frequency region below 2 kHz,
not severe hearing impairment or impairment in the regions of greatest
hearing sensitivity. If hearing impairment occurs, it is most likely
that the affected animal would lose a few decibels in its hearing
sensitivity, which in most cases is not likely to meaningfully affect
its ability to forage and communicate with conspecifics. As described
above, we expect that marine mammals would be likely to move away from
a sound source that represents an aversive stimulus, especially at
levels that would be expected to result in PTS, given sufficient notice
through use of soft start.
The project also is not expected to have significant adverse
effects on affected marine mammals' habitat. The project activities
would not modify existing marine mammal habitat for a significant
amount of time. The activities may cause some fish or invertebrates to
leave the area of disturbance, thus temporarily impacting marine
mammals' foraging opportunities in a limited portion of the foraging
range; but, because of the short duration of the activities, the
relatively small area of the habitat that may be affected, and the
availability of nearby habitat of similar or higher value, the impacts
to marine mammal habitat are not expected to cause significant or long-
term negative consequences.
Nearly all inland waters of southeast Alaska, including Auke Bay,
are included in the southeast Alaska humpback whale feeding BIA
(Ferguson et al., 2015), though humpback whale distribution in
southeast Alaska varies by season and waterway (Dahlheim et al., 2009).
Humpback whales are present within Auke Bay intermittently and in low
numbers. The area of the BIA that may be affected by the proposed
project is small relative to the overall area of the BIA. The southeast
Alaska humpback whale feeding BIA is active between March and November
while the proposed project is scheduled to occur between November and
March, resulting in only two months of overlap. Additionally, pile
driving associated with the project is expected to take only 61 days,
further reducing the temporal overlap with the BIA. Therefore, the
proposed project is not expected to have significant adverse effects on
the foraging of Alaska humpback whale. No areas of specific biological
importance (e.g., ESA critical habitat, other BIAs, or other areas) for
any other species are known to co-occur with the project area.
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 any of the species
or stocks through effects on annual rates of recruitment or survival:
No serious injury or mortality is anticipated or proposed
for authorization;
Any Level A harassment exposures (i.e., to harbor
porpoises and harbor seals, only) are anticipated to result in slight
PTS (i.e., of a few decibels), within the lower frequencies associated
with pile driving;
The anticipated incidents of Level B harassment would
consist of, at worst, temporary modifications in behavior that would
not result in fitness impacts to individuals;
The area impacted by the specified activity is very small
relative to the overall habitat ranges of all species, does not include
ESA-designated critical habitat, and only temporally overlaps with the
southeast Alaska humpback whale feeding BIA for two months of the
planned six months of activity; and
The proposed mitigation measures are expected to reduce
the effects of the specified activity to the level of least practicable
adverse impact.
In combination, we believe that these factors, as well as the
available body of evidence from other similar activities, demonstrate
that the potential effects of the specified activities would have only
minor, short-term effects on individuals. The specified activities are
not expected to affect the reproduction or survival of any individual
marine mammals and, therefore, would not result in impacts on rates of
recruitment or survival for any species or stock.
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 would have a negligible impact
on all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in
[[Page 22432]]
practice, where estimated numbers are available, NMFS compares the
number of individuals taken to the most appropriate estimation of
abundance of the relevant species or stock in our determination of
whether an authorization is limited to small numbers of marine mammals.
When the predicted number of individuals to be taken is fewer than one-
third of the species or stock abundance, the take is considered to be
of small numbers. Additionally, other qualitative factors may be
considered in the analysis, such as the temporal or spatial scale of
the activities.
Table 8 demonstrates the number of animals that could be exposed to
received noise levels that could cause Level A and Level B harassment
for the proposed work in Auke Bay. Our analysis shows that less than 28
percent of each affected stock could be taken by harassment. The
numbers of animals proposed to be taken for these stocks would be
considered small relative to the relevant stock's abundances, even if
each estimated taking occurred to a new individual--an extremely
unlikely scenario.
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 would 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 would 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.
The proposed project is not known to occur in an important
subsistence hunting area. It is a developed area with regular marine
vessel traffic. However, ADOT&PF plans to provide advanced public
notice of construction activities to reduce construction impacts on
local residents, ferry travelers, adjacent businesses, and other users
of the Auke Bay ferry terminal and nearby areas. This would include
notification to local Alaska Native tribes that may have members who
hunt marine mammals for subsistence. Of the marine mammals considered
in this IHA application, only harbor seals are known to be used for
subsistence in the project area. If any tribes express concerns
regarding project impacts to subsistence hunting of marine mammals,
further communication between would take place, including provision of
any project information, and clarification of any mitigation and
minimization measures that may reduce potential impacts to marine
mammals.
Based on the description of the specified activity, the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there would
not be an unmitigable adverse impact on subsistence uses from ADOT&PF's
proposed activities.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally whenever we propose to authorize take for
endangered or threatened species, in this case with the Alaska Regional
Office.
NMFS is proposing to authorize take of wDPS Steller sea lions and
Mexico DPS humpback whales, which are listed under the ESA.
The Permits and Conservation Division has requested initiation of
section 7 consultation with the Alaska Region for the issuance of this
IHA. NMFS would conclude the ESA consultation prior to reaching a
determination regarding the proposed issuance of the authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to ADOT&PF for conducting pile installation and removal
activities at the Auke Bay East ferry terminal between October 1, 2023
and September 30, 2024, 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.
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
action. We also request comment on the potential renewal of this
proposed IHA as described in the paragraph below. Please include with
your comments any supporting data or literature citations to help
inform decisions on the request for this IHA or a subsequent renewal
IHA.
On a case-by-case basis, NMFS may issue a one-time, one-year
renewal IHA following notice to the public providing an additional 15
days for public comments when (1) up to another year of identical or
nearly identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity 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 the
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).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS
[[Page 22433]]
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures would remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: April 7, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2023-07729 Filed 4-12-23; 8:45 am]
BILLING CODE 3510-22-P