[Federal Register Volume 85, Number 63 (Wednesday, April 1, 2020)]
[Notices]
[Pages 18196-18213]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-06787]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XR097]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Gastineau Channel Historical
Society Sentinel Island Moorage Float Project, Juneau, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from Gastineau Channel Historical
Society (GCHS) for authorization to take marine mammals incidental to
Sentinel Island Moorage Float project near 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 activities. NMFS
is also requesting comments on a possible one-year renewal that could
be issued under certain circumstances and if all requirements are met,
as described in Request for Public Comments at the end of this notice.
NMFS will consider public comments prior to making any final decision
on the issuance of the requested MMPA authorizations and agency
responses will be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than May 1,
2020.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Physical comments should be sent to
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments
should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. All comments received are a part of the
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Dwayne Meadows, Ph.D., Office of
Protected Resources, NMFS, (301) 427-8401. Electronic copies of the
application and supporting documents, as well as a list of the
references cited in this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth.
[[Page 18197]]
The definitions of all applicable MMPA statutory terms cited above
are included in the relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (incidental harassment authorizations with
no anticipated serious injury or mortality) of the Companion Manual for
NOAA Administrative Order 216-6A, which do not individually or
cumulatively have the potential for significant impacts on the quality
of the human environment and for which we have not identified any
extraordinary circumstances that would preclude this categorical
exclusion. Accordingly, NMFS has preliminarily determined that the
issuance of the proposed IHA qualifies to be categorically excluded
from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On 24 October 2019, NMFS received a request from GCHS for an IHA to
take marine mammals incidental to Sentinel Island Moorage Float project
near Juneau, Alaska. The application was deemed adequate and complete
on February 7, 2020. GCHS's request is for take of seven species
(consisting of eight stocks) of marine mammals by Level B harassment
and/or Level A harassment. Neither GCHS nor NMFS expects serious injury
or mortality to result from this activity and, therefore, an IHA is
appropriate.
Description of Proposed Activity
Overview
The project consists of the construction of an access float to more
easily access Sentinel Island within Favorite Channel/Lynn Canal near
Juneau, Alaska. GCHS would install a pile supported marine float with a
metal gangway spanning from the float to a timber platform on Sentinel
Island. The project includes the following in-water components: driving
six 24-inch diameter steel pipe piles to support the float and seaward
end of the gangway. Pile driving would be by vibratory pile driving to
install the piles until down-the-hole (DTH) drilling is needed to rock
socket the piles. Impact pile driving will only be used for piles that
encounter soils too dense to penetrate with the vibratory equipment,
which is not expected.
The pile driving or DTH drilling can result in take of marine
mammals from sound in the water which results in behavioral harassment
(Level B harassment) or auditory injury (Level A harassment). The
footprint of the project is approximately one square mile around the
project site. The project will take no more than 6 days of pile-
driving/DTH drilling.
Dates and Duration
The work for which take will be authorized will occur between July
15, 2020 and September 20, 2020. Noise generating activities will not
overlap with high densities of marine mammal prey that occur March 1
through May 31. The daily construction window for pile driving would
begin no sooner than 30 minutes after sunrise and would end 30 minutes
prior to sunset to allow for marine mammal monitoring.
Specific Geographic Region
The project site is located at Sentinel Island at the northern end
of Favorite Channel at its convergence with Lynn Canal near Juneau,
Alaska (Figure 1). In 2004 the Sentinel Island Lighthouse was
transferred to the Gastineau Channel Historical Society from the U.S.
Coast Guard. The proposed mooring float is adjacent to the lighthouse
on the island. In a similar location to the proposed float there was an
old timber dock with a hoist house that was demolished in 2004.
BILLING CODE 3510-22-P
[[Page 18198]]
[GRAPHIC] [TIFF OMITTED] TN01AP20.000
BILLING CODE 3510-22-C
Several seasonally available prey species are abundant within the
project area. Herring (Clupea pallasii) are abundant in dense
aggregations in the spring and fall, coinciding with when Steller sea
lion numbers peak at Benjamin Island to the north (Womble 2003). In
Southeast Alaska, spawning of eulachon (Thaleichtys pacificus) and
capelin (Mallotus villosus) also occurs in the spring (Womble et al.
2009).
The underwater acoustic environment in the project area is
dominated by ambient noise from day-to-day vessel activities.
Detailed Description of Specific Activity
The 16 by 60 foot float and 8 by 88 foot gangway will be fabricated
and moved to the installation site. To support these structures, six
24-inch diameter steel pipes would be driven into the substrate at the
project location. The pipe piles would be installed to a depth of at
least 15 feet or more below the surface using a crane-mounted vibratory
and/or impact hammer located on a barge. It may take up to about 60
minutes per pile of vibratory driving to set each pile. If impact
hammering is used, about 250 strikes would be needed to drive each of
the piles to a sufficient depth which may require about 15 minutes of
hammering. Installation will begin with use of the vibratory hammer,
then drilling will begin at the bedrock interface and at the end the
final setting of the pile in the drilled socket will be done with the
vibratory hammer. DTH drilling will be used to install the rock
sockets. It is estimated that about 6 hours (maximum) would be required
to drive each pile and they would be proofed the same day.
Multiple piles would not be concurrently driven. Under the best-
case scenario, using solely vibratory and DTH drilling, two piles would
be set in
[[Page 18199]]
a day. Therefore, the duration of drilling activity for the four piles
could be as short as 3 days or as long as 6 days. Thus in the worst
case, the entire project would take a total of 6 days of pile driving/
drilling.
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.
Additional information regarding population trends and threats may be
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (https://www.fisheries.noaa.gov/find-species).
Table 1 lists all species with expected potential for occurrence in
Juneau, Alaska and summarizes information related to the population or
stock, including regulatory status under the MMPA and ESA and potential
biological removal (PBR), where known. For taxonomy, we follow
Committee on Taxonomy (2019). PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS's
SARs). While no mortality is anticipated or authorized here, PBR and
annual serious injury and mortality from anthropogenic sources are
included here as gross indicators of the status of the species and
other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS's stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS's U.S. Alaska SARs (e.g., Muto et al., 2019). All values presented
in Table 1 are the most recent available at the time of publication and
are available in the draft 2019 SARs (Muto et al., 2019).
Table 1--Marine Mammals Potentially Present in the Vicinity of the Study Areas
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Stock abundance (CV,
ESA/MMPA status; Nmin, most recent Annual M/
Common name Scientific name Stock Strategic (Y/N) \1\ abundance survey) \2\ PBR SI \3\
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Physeteridae
Sperm whale........................ Physeter North Pacific........ -; N N/A (see SAR, N/A, See SAR 4.4
macrocephalus. 2015), see text.
Family Balaenopteridae (rorquals)
Humpback Whale..................... Megaptera Central North Pacific -; N (Hawaii DPS) 10,103 (0.3, 7,890, 83 25
novaeangliae. 2006).
Central North Pacific T,D,Y (Mexico DPS) 3264................. N/A N/A
Minke whale \4\.................... Balaenoptera Alaska............... -; N N/A, see text........ N/A 0
acutorostrata.
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae
Killer whale \5\................... Orcinus orca......... Alaska Resident...... -; Y 2347................. 24 1
Northern Resident.... 261.................. 1.96 0
West Coast transient. 243.................. 2.4 0
Family Phocoenidae (porpoises)
Dall's porpoise \4\................ Phocoenoides dalli... Alaska............... -; N 83,400 (0.097, N/A, N/A 38
1991).
Harbor porpoise.................... Phocoena phocoena.... Southeast Alaska..... -; Y 975 (2012)........... 8.9 34
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Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
sea lions)
Steller sea lion................... Eumetopias jubatus... Eastern U.S.......... -; N 41,638 (n/a; 41,638; 2,498 108
2015).
Steller sea lion................... Eumetopias jubatus... Western U.S.......... E,D,Y 54,268 (see SAR, 326 247
54,267, 2017).
Family Phocidae (earless seals)
Harbor seal........................ Phoca vitulina Lynn Canal/Stephens -; N 9,478 (see SAR, 155 50
richardii. Passage. 8,605, 2011).
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\1\- Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\- NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable
\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.
\4\- The most recent abundance estimate is >8 years old, there is no official current estimate of abundance available for this stock.
[[Page 18200]]
\5\- NMFS has preliminary genetic information on killer whales in Alaska which indicates that the current stock structure of killer whales in Alaska
needs to be reassessed. NMFS is evaluating the new genetic information. A complete revision of the killer whale stock assessments will be postponed
until the stock structure evaluation is completed and any new stocks are identified'' (Muto, Helker et al. 2018). For the purposes of this IHA
application, the existing stocks are used to estimate potential takes.
All species that could potentially occur in the proposed survey
areas are included in Table 1. As described below, seven species (with
eight managed stocks) temporally and spatially co-occur with the
activity to the degree that take is reasonably likely to occur, and we
have proposed authorizing it. Sperm whales are considered extra-limital
and will not be considered further.
In addition, the northern sea otter may be found in the project
vicinity. However, that species is managed by the U.S. Fish and
Wildlife Service and is not considered further in this document.
Humpback Whale
Humpback whales (Megaptera novaeangliae) in the North Pacific
migrate from low-latitude breeding and calving grounds to form
geographically distinct aggregations on higher-latitude feeding
grounds. They occur in Lynn Canal where they feed on aggregations of
herring in lower Lynn Canal.
In 2016 NMFS revised the ESA listing of humpback whales (81 FR
62259; September 8, 2016). NMFS is in the process of reviewing humpback
whale stock structure and abundance under the MMPA in light of the ESA
revisions. The MMPA stock in Alaska is considered to be the Central
North Pacific stock. Humpbacks from 2 of the 14 newly identified
Distinct Population Segments (DPSs) occur in the project area: The
Mexico DPS, which is a threatened species; and the Hawaii DPS, which is
not protected under the ESA. NMFS considers humpback whales in
Southeast Alaska to be 94 percent comprised of the Hawaii DPS and 6
percent of the Mexico DPS (Wade et al., 2016). While the range of the
Mexico DPS extends up to Southeast Alaska, this DPS has never been
reported as far north as Sitka. The likelihood that an individual from
the Mexico DPS is part of the relatively few humpback whales that move
to Lynn Canal is extremely low; nevertheless, we use the 6 percent
estimate to be conservative in this analysis.
On October 9, 2019, NMFS published a proposed rule to designate
critical habitat for the humpback whale (84 FR 54354). Areas proposed
as critical habitat include specific marine areas off the coasts of
California, Oregon, Washington and Alaska, including near the project
area. GCHS expects to complete this project before the critical habitat
designation is effective, therefore we do not consider it further in
this analysis.
Estimates of humpback whale abundance for the Mexico DPS are from
the ESA listing process. Some whale researchers, resource managers, and
whale watching guides track the presence of individual humpback whales
in the Juneau area by unique fluke patterns (Teerlink, 2017). Based on
fluke pattern identification from fluke photographs taken between 2006
and 2014, 179 individual humpback whales were identified from the
Juneau area (Teerlink, 2017). For Lynn Canal/Favorite Channel and other
waters in the project vicinity including Stephens Passage, and Saginaw
Channel, researchers have documented 4 to 18 humpback whales in winter
(Krieger and Wing, 1986; Moran et al., 2018). Straley et al. (2011)
surveyed humpback whales in Lynn Canal from September 15-October 14 in
2007/2008 and during the same months in 2000/2009. During both years a
total of 55 whale sighting (average of approximately 2 whales per day)
were recorded, however in 2007/2008 there were 30 unique whales
identified and in 2008/2009 there were 22 unique whales identified in
the project vicinity.
Dahlheim et al. (2009) found significant difference in the mean
group size of humpback whales from year to year and also found that the
average group size was largest in the fall (September/October), however
no surveys were conducted in August. Information from the fall surveys
is thus utilized, and is conservative because humpback numbers were
found to peak during the fall in Lynn Canal (Straley et al., 2011).
Minke Whale
There are three stocks of minke whales (Balaenopera acutorostrata)
recognized in U.S. waters of the Pacific Ocean; only members of the
Alaska stock could potentially occur within the project area. This
stock has seasonal movements associated with feeding areas that are
generally located at the edge of the pack ice (Muto et al., 2019).
Minke whales are considered to be rare in Lynn Canal (Dahlheim et al.,
2009). However, minke whales forage on schooling fish and may rarely
enter the project area. In 2015, one minke whale was sighted in Taiya
Inlet, northeast of the Project Area (K. Gross, personal communication,
as cited in 84 FR 4777, February 19, 2019).
No comprehensive estimates of abundance have been made for the
Alaska stock or near the project area, but a 2010 survey conducted on
the eastern Bering Sea shelf produced a provisional abundance estimate
of 2,020 whales (Friday et al., 2013).
Killer Whale
NMFS recognizes eight killer whale (Orcinus orca) stocks throughout
the Pacific Ocean. However, only three of these stocks can be found in
Southeast Alaska: (1) the Alaska Resident stock ranges from
southeastern Alaska to the Aleutian Islands and Bering Sea; (2) the
Northern Resident stock occurs from Washington State through part of
southeastern Alaska; and (3) the West Coast Transient stock ranges from
California through southeastern Alaska (Muto et al., 2019). Resident
and transient killer whales are sporadically and seasonally attracted
to Lutak Inlet during the spring to feed on the large aggregations of
fishes and pinnipeds.
Killer whale abundance estimates are determined by a direct count
of individually identifiable animals. Killer whales are observed within
the project area several times annually. Data compiled by Oceanus
Alaska found an average of 25 killer whales in the Statter Harbor area
of Auke Bay each year. While killer whales occurring in Lynn Canal can
belong to one of three stocks, photoidentification studies since 1970
have catalogued most individuals observed in this area as belonging to
the Northern Resident stock. The AG resident pod is one pod known to
frequent the Juneau area (Dahlheim et al., 2009; B. Lambert personal
observation) and has 41 members. This pod is seen in the area
intermittently in groups of up to approximately 25 individuals (B.
Lambert personal observation). The occurrence of transient killer
whales in Lynn Canal increases in summer, with lower numbers observed
in spring and fall. Dahlheim et al. (2009) found the average group size
of resident orcas to be approximately 33 individuals during the summer
(June/July) and 20 during the fall (September/October).
Dall's Porpoise
Dall's porpoise (Phocoenoides dalli) are widely distributed
throughout the region and have been observed in Lynn Canal (Dahlheim et
al., 2009). They were observed more frequently in the spring, tapering
off in summer and fall
[[Page 18201]]
in southeast Alaska (Jefferson et al., 2019). The Alaska stock is the
only Dall's porpoise stock found in Alaska waters. Group sizes were
generally small, under 5 individuals, and during the summer months the
mean group size was 2.6.
Harbor Porpoise
Harbor porpoise (Phocoena phocoena) are common in coastal waters of
Alaska. There are three harbor porpoise stocks in Alaska, but only the
Southeast Alaska stock occurs in the project area (Muto et al., 2019).
Individuals from the Southeast Alaska stock of harbor porpoise are
infrequently observed in Lynn Canal, though they have been observed as
far north as Haines during the summer months (Dahlheim et al., 2015).
Steller Sea Lion
Steller sea lions (Eumetopias jubatus) range along the North
Pacific Rim from northern Japan to California, with centers of
abundance and distribution in the Gulf of Alaska and Aleutian Islands.
Large numbers of individuals widely disperse when not breeding (late
May to early July) to access seasonally important prey resources (Muto
et al., 2019). In 1997 NMFS identified two DPSs of Steller sea lions
under the ESA: a Western DPS and an Eastern DPS (62 FR 24345, May 5,
1997). The Eastern DPS is not ESA-listed, the Western DPS is. For MMPA
purposes the Eastern DPS is called the Eastern U.S. stock and the
Western DPS is called the Western U.S. stock. For simplicity we will
refer to them by their DPS name in this analysis. Most of the Steller
sea lions in southeastern Alaska have been determined to be part of the
Eastern DPS, however, in recent years there has been an increasing
trend of the Western DPS animals occurring and breeding in southeastern
Alaska (Muto et al., 2019).
Steller sea lions have been observed in the project vicinity
throughout the year. Salmon increase in importance as prey for sea
lions from late-October and December. The closest haulout to the
project area is Benjamin Island, about 1 mile northeast. Typically the
sea lions vacate Benjamin Island mid-July through late-September,
however some years individuals have remained. In surveys conducted from
2004 to 2018, Steller sea lions were absent from July 17 through
September 28 at Benjamin Island with the exception of 2005 and 2013. On
July 16, 2005 560 non-pups were observed; on August 9, 2013, 40 non-
pups were counted; and on September 24, 2013, 144 non-pups were
observed (Jemison, Alaska Fish and Game, personal communication).
Individuals from the Western DPS have been observed in the Lynn
Canal area. The percentage of Western DPS animals estimated to occur in
the project area in the summer is estimated to be 1.4 percent (Hastings
et al., in press); for the rest of this analysis we assume that 1.4
percent of the Steller sea lions in the project area are from the
Western DPS.
Harbor Seal
Harbor seals (Phoca vitulina) inhabit coastal and estuarine waters
off Alaska. They haul out on rocks, reefs, beaches, and drifting
glacial ice. Up to 44 percent of their time is spent hauled out, with
hauling out occurring more often during the summer (Pitcher and
Calkins, 1979; Klinkhart et al., 2008). They are opportunistic feeders
and often adjust their distribution to take advantage of locally and
seasonally abundant prey (Womble et al., 2009; Allen and Angliss,
2015). Harbor seals occurring in the project area belong to the Lynn
Canal/Stephens Passage (LC/SP) stock. NOAA 2018 abundance estimates for
the unit in which the action area is located is 42.06 harbor seals at a
haulout on the east coast of Sentinel Island with the 95 percent
confidence interval for that estimate at 134 seals.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in Table 2.
Table 2--Marine Mammal Hearing Groups (NMFS, 2018)
----------------------------------------------------------------------------------------------------------------
Hearing group Generalized hearing range *
----------------------------------------------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales)........... 7 Hz to 35 kHz
Mid-frequency (MF) cetaceans (dolphins, toothed whales, 150 Hz to 160 kHz
beaked whales, bottlenose whales).
High-frequency (HF) cetaceans (true porpoises, Kogia, 275 Hz to 160 kHz
river dolphins, cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true seals)........ 50 Hz to 86 kHz
Otariid pinnipeds (OW) (underwater) (sea lions and fur 60 Hz to 39 kHz
seals).
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\*\ Represents the generalized hearing range for the entire group as a composite (i.e., all species within the
group), where individual species' hearing ranges are typically not as broad. Generalized hearing range chosen
based on ~65 dB threshold from normalized composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges,
[[Page 18202]]
please see NMFS (2018) for a review of available information. Seven
marine mammal species (five cetacean and two pinniped (one otariid and
one phocid) species have the reasonable potential to co-occur with the
proposed survey activities (see Table 1). Of the cetacean species that
may be present, two are classified as low-frequency cetaceans (i.e.,
all mysticete species), one is classified as a mid-frequency cetacean
(i.e., all delphinid and ziphiid species and the sperm whale), and two
are classified as high-frequency cetaceans (i.e., harbor porpoise and
Dall's porpoise).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (ANSI 1994, 1995). The sound level of an area
is defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., waves, wind,
precipitation, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
In-water construction activities associated with the project would
include impact pile driving, vibratory pile driving, and DTH drilling.
The sounds produced by these activities fall into one of two general
sound types: Impulsive and non-impulsive. Impulsive sounds (e.g.,
explosions, gunshots, sonic booms, impact pile driving) are typically
transient, brief (less than 1 second), broadband, and consist of high
peak sound pressure with rapid rise time and rapid decay (ANSI, 1986;
NIOSH, 1998; ANSI, 2005; NMFS, 2018). Non-impulsive sounds (e.g.,
machinery operations such as drilling or dredging, vibratory pile
driving, and active sonar systems) can be broadband, narrowband or
tonal, brief or prolonged (continuous or intermittent), and typically
do not have the high peak sound pressure with raid rise/decay time that
impulsive sounds do (ANSI 1995; NIOSH 1998; NMFS 2018). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward 1997 in Southall et al., 2007).
Two types of pile hammers would be used on this project: Impact and
vibratory. Impact hammers operate by repeatedly dropping a heavy piston
onto a pile to drive the pile into the substrate. Sound generated by
impact hammers is characterized by rapid rise times and high peak
levels, a potentially injurious combination (Hastings and Popper,
2005). Vibratory hammers install piles by vibrating them and allowing
the weight of the hammer to push them into the sediment. Vibratory
hammers produce significantly less sound than impact hammers. Peak
Sound pressure Levels (SPLs) may be 180 dB or greater, but are
generally 10 to 20 dB lower than SPLs generated during impact pile
driving of the same-sized pile (Oestman et al., 2009). Rise time is
slower, reducing the probability and severity of injury, and sound
energy is distributed over a greater amount of time (Nedwell and
Edwards, 2002; Carlson et al., 2005).
DTH drilling would be conducted using a down-the-hole drill
inserted through the hollow steel piles. A DTH drill is a drill bit
that drills through the bedrock using a pulse mechanism that functions
at the bottom of the hole. This pulsing bit breaks up rock to allow
removal of debris and insertion of the pile. The head extends so that
the drilling takes place just below the pile. The pulsing sounds
produced by the DTH drilling method occur in a range of frequencies
that depends on the size and type of the bit and the hammering pressure
applied. Smaller diameter DTH drilling produces sounds that are
generally continuous while larger and ring-type DTH drills produce
sounds that can be a combination of continuous and impulsive. The DTH
hammering for this project falls in the continuous range. In addition,
this method likely increases sound attenuation because the noise is
primarily contained within the steel pile and below ground as opposed
to impact hammer driving methods which occur at the top of the pile and
introduce sound into the water column to a greater degree. See also our
detailed discussion of this sound source in the notice of issuance of
an IHA for Ferry Berth Improvements in Tongass Narrows, Alaska https://www.govinfo.gov/content/pkg/FR-2020-01-07/pdf/2020-00038.pdf.
The likely or possible impacts of GCHS's proposed activity on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, any impacts to marine
mammals are expected to primarily be acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
installation and drilling.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving and DTH drilling is the primary means by
which marine mammals may be harassed from GCHS's specified activity. In
general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007). Generally, exposure to
pile driving and drilling noise has the potential to result in auditory
threshold shifts and behavioral reactions (e.g., avoidance, temporary
cessation of foraging and vocalizing, changes in dive behavior).
Exposure to anthropogenic noise can also lead to
[[Page 18203]]
non-observable physiological responses such an increase in stress
hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions such
as communication and predator and prey detection. The effects of pile
driving and drilling noise on marine mammals are dependent on several
factors, including, but not limited to, sound type (e.g., impulsive vs.
non-impulsive), the species, age and sex class (e.g., adult male vs.
mom with calf), duration of exposure, the distance between the pile and
the animal, received levels, behavior at time of exposure, and previous
history with exposure (Wartzok et al., 2003; Southall et al., 2007).
Here we discuss physical auditory effects (threshold shifts) followed
by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (2018), there are numerous factors
to consider when examining the consequence of TS, including, but not
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough
duration or to a high enough level to induce a TS, the magnitude of the
TS, time to recovery (seconds to minutes or hours to days), the
frequency range of the exposure (i.e., spectral content), the hearing
and vocalization frequency range of the exposed species relative to the
signal's frequency spectrum (i.e., how animal uses sound within the
frequency band of the signal; e.g., Kastelein et al., 2014), and the
overlap between the animal and the source (e.g., spatial, temporal, and
spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). Available data from
humans and other terrestrial mammals indicate that a 40 dB threshold
shift approximates PTS onset (see Ward et al., 1958, 1959; Ward, 1960;
Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson and
Hu, 2008). PTS levels for marine mammals are estimates, with the
exception of a single study unintentionally inducing PTS in a harbor
seal (Kastak et al., 2008), there are no empirical data measuring PTS
in marine mammals, largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels
inducing PTS are not typically pursued or authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--A temporary, reversible increase
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018). Based on data from cetacean TTS measurements (see
Southall et al., 2007), a TTS of 6 dB is considered the minimum
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et
al., 2000; Finneran et al., 2000, 2002). As described in Finneran
(2016), marine mammal studies have shown the amount of TTS increases
with cumulative sound exposure level (SELcum) in an
accelerating fashion: At low exposures with lower SELcum,
the amount of TTS is typically small and the growth curves have shallow
slopes. At exposures with higher SELcum, the growth curves
become steeper and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in auditory
masking, below). For example, a marine mammal may be able to readily
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal
is traveling through the open ocean, where ambient noise is lower and
there are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts. We note that reduced hearing sensitivity as
a simple function of aging has been observed in marine mammals, as well
as humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis)) and five species of pinnipeds exposed to a limited
number of sound sources (i.e., mostly tones and octave-band noise) in
laboratory settings (Finneran, 2015). TTS was not observed in trained
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to
impulsive noise at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises
have a lower TTS onset than other measured pinniped or cetacean species
(Finneran, 2015). The potential for TTS from impact pile driving
exists. After exposure to playbacks of impact pile driving sounds (rate
2760 strikes/hour) in captivity, mean TTS increased from 0 dB after 15
minute exposure to 5 dB after 360 minute exposure; recovery occurred
within 60 minutes (Kastelein et al., 2016). Additionally, the existing
marine mammal TTS data come from a limited number of individuals within
these species. No data are available on noise-induced hearing loss for
mysticetes. For summaries of data on TTS in marine mammals or for
further discussion of TTS onset thresholds, please see Southall et al.
(2007), Finneran and Jenkins (2012), Finneran (2015), and Table 5 in
NMFS (2018).
Installing piles requires a combination of impact pile driving,
vibratory pile driving, and DTH drilling. For the project, these
activities would not occur at the same time and there would likely be
pauses in activities producing the sound during each day. Given these
pauses and that many marine mammals are likely moving through the
action area and not remaining for extended periods of time, the
potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
removal and drilling also has the potential to behaviorally disturb
marine mammals. Available studies show wide variation in response to
underwater sound; therefore, it is difficult to predict specifically
how any given sound in a particular instance might affect marine
mammals perceiving the signal. If a marine mammal does react briefly to
an underwater sound by changing its behavior or moving a small
distance, the impacts of the change are unlikely to be significant to
the individual, let alone the stock or population. However, if a sound
source displaces marine mammals from an important feeding or breeding
area for a prolonged period, impacts on individuals and populations
could be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007;
NRC, 2005).
Disturbance may result in changing durations of surfacing and
dives, number of blows per surfacing, or
[[Page 18204]]
moving direction and/or speed; reduced/increased vocal activities;
changing/cessation of certain behavioral activities (such as
socializing or feeding); visible startle response or aggressive
behavior (such as tail/fluke slapping or jaw clapping); avoidance of
areas where sound sources are located. Pinnipeds may increase their
haul-out time, possibly to avoid in-water disturbance (Thorson and
Reyff, 2006). Behavioral responses to sound are highly variable and
context-specific and any reactions depend on numerous intrinsic and
extrinsic factors (e.g., species, state of maturity, experience,
current activity, reproductive state, auditory sensitivity, time of
day), as well as the interplay between factors (e.g., Richardson et
al., 1995; Wartzok et al., 2003; Southall et al., 2007; Weilgart, 2007;
Archer et al., 2010). Behavioral reactions can vary not only among
individuals but also within an individual, depending on previous
experience with a sound source, context, and numerous other factors
(Ellison et al., 2012), and can vary depending on characteristics
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). In general,
pinnipeds seem more tolerant of, or at least habituate more quickly to,
potentially disturbing underwater sound than do cetaceans, and
generally seem to be less responsive to exposure to industrial sound
than most cetaceans. Please see Appendices B and C of Southall et al.
(2007) for a review of studies involving marine mammal behavioral
responses to sound.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
In 2016, the Alaska Department of Transportation and Public
Facilities (ADOT&PF) documented observations of marine mammals during
construction activities (i.e., pile driving and down-hole drilling) at
the Kodiak Ferry Dock (see 80 FR 60636, October 7, 2015). In the marine
mammal monitoring report for that project (ABR 2016), 1,281 Steller sea
lions were observed within the Level B disturbance zone during pile
driving or drilling (i.e., documented as Level B harassment take). Of
these, 19 individuals demonstrated an alert behavior, 7 were fleeing,
and 19 swam away from the project site. All other animals (98 percent)
were engaged in activities such as milling, foraging, or fighting and
did not change their behavior. In addition, two sea lions approached
within 20 meters of active vibratory pile driving activities. Three
harbor seals were observed within the disturbance zone during pile
driving activities; none of them displayed disturbance behaviors.
Fifteen killer whales and three harbor porpoise were also observed
within the Level B harassment zone during pile driving. The killer
whales were travelling or milling while all harbor porpoises were
travelling. No signs of disturbance were noted for either of these
species. Given the similarities in activities and habitat and the fact
the same species are involved, we expect similar behavioral responses
of marine mammals to GCHS's specified activity. That is, disturbance,
if any, is likely to be temporary and localized (e.g., small area
movements). Monitoring reports from other recent pile driving and DTH
drilling projects in Alaska have observed similar behaviors (for
example, the Biorka Island Dock Replacement Project).
Masking--Sound can disrupt behavior through masking, or interfering
with, an animal's ability to detect, recognize, or discriminate between
acoustic signals of interest (e.g., those used for intraspecific
communication and social interactions, prey detection, predator
avoidance, navigation) (Richardson et al., 1995). Masking occurs when
the receipt of a sound is interfered with by another coincident sound
at similar frequencies and at similar or higher intensity, and may
occur whether the sound is natural (e.g., snapping shrimp, wind, waves,
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar,
seismic exploration) in origin. The ability of a noise source to mask
biologically important sounds depends on the characteristics of both
the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions. Masking of natural sounds can result when human activities
produce high levels of background sound at frequencies important to
marine mammals. Conversely, if the background level of underwater sound
is high (e.g. on a day with strong wind and high waves), an
anthropogenic sound source would not be detectable as far away as would
be possible under quieter conditions and would itself be masked. The
Juneau area contains active commercial shipping and ferry operations as
well as numerous recreational and commercial vessels; therefore,
background sound levels in the area are already elevated.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and DTH drilling that have the potential to cause behavioral
harassment, depending on their distance from pile driving activities.
Cetaceans are not expected to be exposed to airborne sounds that would
result in harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the acoustic criteria. We recognize that
pinnipeds in the water could be exposed to airborne sound that may
result in behavioral harassment when looking with their heads above
water. Most likely, airborne sound would cause behavioral responses
similar to those discussed above in relation to underwater sound. For
instance, anthropogenic sound could cause hauled out pinnipeds to
exhibit changes in their normal behavior, such as reduction in
vocalizations, or cause them to temporarily abandon the area and move
further from the source. However, these animals would previously have
been `taken' because of exposure to underwater sound above the
behavioral harassment thresholds, which are in all cases larger than
those associated with airborne sound. Thus, the behavioral harassment
of these animals is already accounted for in these estimates of
potential take. 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.
[[Page 18205]]
Marine Mammal Habitat Effects
GCHS's construction activities at Sentinel Island could have
localized, temporary impacts on marine mammal habitat and their prey by
increasing in-water sound pressure levels and slightly decreasing water
quality. Increased noise levels may affect acoustic habitat (see
masking discussion above) and adversely affect marine mammal prey in
the vicinity of the project area (see discussion below). During impact
pile driving, elevated levels of underwater noise would ensonify Lynn
Canal where both fishes and mammals occur and could affect foraging
success. Currently, there are a few dozen annual vessel landings at
Sentinel Island. With the new dock there would be up to two tour
landings daily during the summer.
Construction activities are of short duration and would likely have
temporary impacts on marine mammal habitat through increases in
underwater and airborne sound.
In-water pile driving, and drilling activities would also cause
short-term effects on water quality due to increased turbidity. Local
strong currents are anticipated to disburse suspended sediments
produced by project activities at moderate to rapid rates depending on
tidal stage. GCHS would employ standard construction best management
practices (BMPs; see section 11 in application), thereby reducing any
impacts. Therefore, the impact from increased turbidity levels is
expected to be discountable.
In-Water Construction Effects on Potential Foraging Habitat
The area likely impacted by the project is relatively small
compared to the available habitat in Lynn Canal (e.g., most of the
impacted area is limited to the east side of Sentinel Island in the
Favorite Channel) and does not include any BIAs. One ESA-designated
critical habitat area for Steller sea lions is nearby on Benjamin
Island and would be within the Level B harassment zone for sound but
there would be no direct effects on the critical habitat. Pile
installation and drilling may temporarily increase turbidity resulting
from suspended sediments. Any increases would be temporary, localized,
and minimal. GCHS 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 be close enough to the project
pile driving areas to experience effects of turbidity, and any
pinnipeds would be transiting the area and could avoid localized areas
of turbidity. Therefore, the impact from increased turbidity levels is
expected to be discountable to marine mammals. Furthermore, pile
driving at the project site would not obstruct movements or migration
of marine mammals.
Avoidance by potential prey (i.e., fish) of the immediate area due
to the temporary loss of this foraging habitat is also possible. The
duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. Any behavioral avoidance by fish of the
disturbed area would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity in Lynn Canal and
the project would occur outside the peak eulachon, capelin and salmonid
runs.
The duration of the construction activities is relatively short.
The construction window is for a maximum of 4-5 months with only a
maximum of 6 days of pile driving. During each day, construction
activities would only occur during daylight hours. Impacts to habitat
and prey are expected to be minimal based on the short duration of
activities.
In-water Construction Effects on Potential Prey (Fish)--
Construction activities would produce continuous (i.e., vibratory pile
driving and DTH drilling) and pulsed (i.e. impact driving) sounds. Fish
react to sounds that are especially strong and/or intermittent low-
frequency sounds. Short duration, sharp sounds can cause overt or
subtle changes in fish behavior and local distribution. Hastings and
Popper (2005) identified several studies that suggest fish may relocate
to avoid certain areas of sound energy. Additional studies have
documented effects of pile driving on fish, although several are based
on studies in support of large, multiyear bridge construction projects
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Sound
pulses at received levels of 160 dB may cause subtle changes in fish
behavior. SPLs of 180 dB may cause noticeable changes in behavior
(Pearson et al., 1992; Skalski et al., 1992). SPLs of sufficient
strength have been known to cause injury to fish and fish mortality.
The most likely impact to fish from pile driving and drilling
activities at the project area would be temporary behavioral avoidance
of the area. The duration of fish avoidance of this area after pile
driving stops is unknown, but a rapid return to normal recruitment,
distribution and behavior is anticipated. 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 forage fish and juvenile salmonid
outmigratory routes in the project area. Both herring and salmon form a
significant prey base for Steller sea lions, herring is a primary prey
species of humpback whales, and herring, capelin and salmon are
components of the diet of many other marine mammal species that occur
in the project area. Increased turbidity is expected to occur in the
immediate vicinity (on the order of 10 feet or less) of construction
activities. However, suspended sediments and particulates are expected
to dissipate quickly within a single tidal cycle. Given the limited
area affected and high tidal dilution rates any effects on forage fish
and salmon are expected to be minor or negligible. In addition, best
management practices would be in effect, which would limit the extent
of turbidity to the immediate project area. Finally, exposure to turbid
waters from construction activities is not expected to be different
from the current exposure; fish and marine mammals in the Lynn Canal
region are routinely exposed to substantial levels of suspended
sediment from glacial sources.
In summary, given the short daily duration of sound associated with
individual pile driving and drilling events, the small number of total
piles, and the relatively small areas being affected, pile driving and
drilling activities associated with the proposed action are not likely
to have a permanent, adverse effect on any fish habitat, or populations
of fish species. Thus, we conclude that impacts of the specified
activity are not likely to have more than short-term adverse effects on
any prey habitat or populations of prey species. Further, any impacts
to marine mammal habitat are not expected to result in significant or
long-term consequences for individual marine mammals, or to contribute
to adverse impacts on their populations.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers'' and the negligible impact
determination.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the
[[Page 18206]]
MMPA defines ``harassment'' as any act of pursuit, torment, or
annoyance, which (i) has the potential to injure a marine mammal or
marine mammal stock in the wild (Level A harassment); or (ii) has the
potential to disturb a marine mammal or marine mammal stock in the wild
by causing disruption of behavioral patterns, including, but not
limited to, migration, breathing, nursing, breeding, feeding, or
sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic source (i.e., vibratory or impact pile driving or DTH
drilling) has the potential to result in disruption of behavioral
patterns for individual marine mammals. There is also some potential
for auditory injury (Level A harassment) to result, primarily for
mysticetes, high frequency species and pinnipeds because predicted
auditory injury zones are larger than for mid-frequency species.
Auditory injury is unlikely to occur for mid-frequency species and
otariids. The proposed mitigation and monitoring measures are expected
to minimize the severity of the taking to the extent practicable.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
and the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring results or average group size). Below, we describe the
factors considered here in more detail and present the proposed take
estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed acoustic
thresholds that identify the received level of underwater sound above
which exposed marine mammals would be reasonably expected to be
behaviorally harassed (equated to Level B harassment) or to incur PTS
of some degree (equated to Level A harassment).
Level B Harassment for non-explosive sources--Though significantly
driven by received level, the onset of behavioral disturbance from
anthropogenic noise exposure is also informed to varying degrees by
other factors related to the source (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on what the available science indicates
and the practical need to use a threshold based on a factor that is
both predictable and measurable for most activities, NMFS uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS predicts that marine mammals are
likely to be behaviorally harassed in a manner we consider Level B
harassment when exposed to underwater anthropogenic noise above
received levels of 120 dB re 1 microPascal ([mu]Pa) (root mean square
(rms)) for continuous (e.g., vibratory pile-driving, drilling) and
above 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g.,
impact pile driving) or intermittent (e.g., scientific sonar) sources.
GCHS's proposed activity includes the use of continuous (vibratory
pile-driving, drilling) and impulsive (impact pile-driving) sources,
and therefore the 120 and 160 dB re 1 [mu]Pa (rms) thresholds are
applicable.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual
criteria to assess auditory injury (Level A harassment) to five
different marine mammal groups (based on hearing sensitivity) as a
result of exposure to noise from two different types of sources
(impulsive or non-impulsive). GCHS's activity includes the use of
impulsive (impact pile-driving) sources.
These thresholds are provided in Table 3. The references, analysis,
and methodology used in the development of the thresholds are described
in NMFS 2018 Technical Guidance, which may be accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds\*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
[[Page 18207]]
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
For vibratory pile driving we determined a source level of 161 dB
(RMS SPL) at 10m was most appropriate. The closest known measurements
of sound levels for vibratory pile installation of 16-inch steel piles
are from the U.S. Navy Proxy Sound Source Study for projects in Puget
Sound (U.S. Navy 2015). Based on the projects analyzed it was
determined that 16- to 24-inch piles exhibited similar sound source
levels. For DTH drilling we used a source level of 166.2 dB (RMS SPL);
this is derived from Denes et al. (2016), where they drilled 24-inch
piles near Kodiak, AK. To be conservative, since DTH drilling and
vibratory pile driving would occur on the same day, the applicant used
the higher of the vibratory and DTH source levels (166.2dB) and assumed
all drilling/driving time in a day was at this higher level. For impact
pile driving of 24-inch piles, sound measurements were used from the
literature review in Appendix H of the AKDOT&PF study (Yurk et al.
2015) for 24-inch piles driven in the Columbia River with a diesel
impact hammer (190 dB RMS, 205 dB Peak, 175 dB SS SEL).
We assumed no more than two piles per day with DTH drilling as the
duration per pile was assumed to be 6 hours. For impact pile driving
activities we also assumed no more than 2 piles per day and 250 strikes
per pile. In all cases we used a propagation loss coefficient of 15
logR as most appropriate for these stationary, in-shore sources.
When the NMFS Technical Guidance (2016) was published, in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes. We note that
because of some of the assumptions included in the methods used for
these tools, we anticipate that isopleths produced are typically going
to be overestimates of some degree, which may result in some degree of
overestimate of Level A harassment take. However, these tools offer the
best way to predict appropriate isopleths when more sophisticated 3D
modeling methods are not available, and NMFS continues to develop ways
to quantitatively refine these tools, and will qualitatively address
the output where appropriate. For stationary sources, such as pile
driving and drilling in this project, NMFS User Spreadsheet predicts
the distance at which, if a marine mammal remained at that distance the
whole duration of the activity, it would incur PTS. Inputs used in the
User Spreadsheet, and the resulting isopleths are reported below.
NMFS User spreadsheet input scenarios for vibratory pile driving/
DTH drilling and impact pile driving are shown in Table 4. These input
scenarios lead to PTS isopleth distances (Level A thresholds) of
anywhere from 7 to 220 meters (22 to 720 ft), depending on the marine
mammal group and scenario (Table 5).
Table 4--NMFS User Spreadsheet Inputs
------------------------------------------------------------------------
User spreadsheet input
-------------------------------------------------------------------------
Vibratory pile
driving/DTH Impact pile
drilling driving
------------------------------------------------------------------------
Spreadsheet Tab Used............. A.1) Vibratory E.1) Impact pile
pile driving. driving.
Source Level..................... 166.2 dB RMS...... 175 dB SS SEL.
Weighting Factor Adjustment (kHz) 2.5............... 2.
(a) Number of strikes per pile... N/A............... 250.
(a) Activity Duration (h:min) 12:00............. N/A.
within 24-h period.
Propagation (xLogR).............. 15................ 15.
Distance of source level 10................ 10.
measurement (meters).
Number of piles per day.......... 2................. 2.
------------------------------------------------------------------------
Table 5--NMFS User Spreadsheet Outputs: Level B and Level A (PTS) Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
Behavioral PTS isopleths (meters) (level A)
disturbance ---------------------------------------------------------------------------------------------------
Activity (level B) all Humpback + minke Harbor + dall's
species whales Killer whales porpoise Harbor seals Stellar sea lions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Driving/DTH drilling.. 12.1 km (7.5 80 m (263 feet)... 7 m (23 feet)..... 118 m (387 feet).. 48.3 m (159 feet). 4 m (13 feet)
miles) *.
Impact Driving.................. 1 km (3280 ft).... 184 m (605 ft).... 6.6 m (22 feet)... 220 m (720 ft).... 99 m (325 ft)..... 8 m (25 ft)
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Lynn Canal is smaller than this, therefore extent of actual impacts will be constrained by land.
The distances to the Level B harassment threshold of 120 dB RMS are
12.1 km (7.5 miles) miles for vibratory pile driving and 1 km (3280 ft)
for impact driving. The enclosed nature of Lutak Inlet restricts the
propagation of noise in all directions before noise levels reduce below
the Level B harassment threshold for vibratory pile driving/DTH)
Therefore, the area ensonified to the Level B harassment threshold is
truncated by land in all directions. The ensonified area of the
vibratory/drilling Level B harassment zone is 47km\2\ (18.15 mi\2\).
Note that thresholds for behavioral disturbance are unweighted with
respect to marine mammal hearing and therefore the thresholds apply to
all species.
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
[[Page 18208]]
We have density information for two species: Dall's porpoise and harbor
porpoise. For the other five species we have information on presence,
group size, and dive durations that we use to derive take estimates.
In this section we then describe for each species how the marine
mammal occurrence and/or density information is brought together to
produce a quantitative take estimate. Level A harassment takes are
requested for Dall's porpoise and harbor porpoise only as they are more
cryptic and could enter a Level A harassment zone undetected. For the
other species, the Level A harassment zones are small and shutdown
measures can be implemented prior to any individual entering the Level
A harassment zones. Take estimates for all stocks are shown in Table 6.
Humpback Whale
Based on local information and Dahlheim et al. (2009) we estimate
that up to eight individuals could be exposed to underwater noise each
day. While individual humpback whales can generally be identified, due
to the size of the monitoring zone it is possible this won't be the
case in some instances. Further, it is possible that different monitors
will sight the same whale, given the size of the monitoring zones and
the distances humpback whales can move in a day. Thus it is
conservatively assumed that there could be up to three interactions
with each individual daily. Our take estimate is then the product of
the number of individuals per day times the number of interactions per
individual per day times the 6 days of the project, or 144 Level B
takes.
For purposes of estimating effects and ESA takes of the Mexico DPS
of humpback whales, we acknowledge that Mexico DPS whales cannot be
readily distinguished from non-listed humpback whales in the project
area. Based on Wade et al. (2016) we estimate that 9 of the 144 takes
will be of the Mexico DPS. However, the average group size in the area
during the fall months was two whales (Dahlheim et al. 2009) and it is
possible that a mother calf pair of the Mexico DPS, or other group of
two Mexico DPS whales, may occur within the project area each day. Thus
it is conservatively assumed that 12 individuals (2 individuals per
day) of the threatened Mexico DPS population may be taken and 132 of
the Hawaiian DPS.
Steller Sea Lions
As discussed above Steller sea lions are typically absent in the
project area from mid-July through September. On the off chance that
Steller sea lions will be present during construction for this project
we used an average of the three sightings discussed above from 2005 and
2013 to estimate the possible number of animals in the area. This
average was 248 individuals. We assume that no more than 248 individual
Steller sea lions will enter the action area on a given day of the
project and calculate expected take as 248 times the 6 days of the
project, or 1,488 takes. As discussed above, some of these takes will
be eastern DPS Steller sea lions and some will be western DPS. We use
the estimate from Hastings et al. (2020) that 1.4 percent of the
animals in the project area are from the western DPS to allot 21 of the
1,488 Level B takes to the western DPS and 1,467 of the takes to the
eastern DPS.
Harbor Seal
As discussed above, researchers estimate that they are 95 percent
confident the population size of harbor seals in the area is not
greater than 134 individuals. We use that estimate as the number of
animals expected in the Level B harassment zone daily. We know from
Klinkhart et al. (2008) that animals dive and resurface every 4
minutes. That translates to potentially 15 sightings per hour. We also
use the estimate that they spend 50 percent of their time hauled out.
The project involved 36 hours of pile driving/drilling total. Take is
estimated to be 134 seals times 7.5 in-water sightings per hour times
36 hours of work, or 36,180 Level B takes.
Dall's Porpoise
Density estimates were determined for Dall's porpoises for areas in
Southeast Alaska, however densities specific to the Lynn Canal/Favorite
Channel area are not available. However, surveys occurred closest to
the project area in 1991, 1992, and 2007. These surveys found densities
(porpoises/100km\2\) during summer months of 18.5, 14.3, and 17.8
(Dahlheim et al., 2009). We used the average of these densities (16.9
porpoises/100 km\2\) to calculate take. As noted above the ensonified
area is 47 km\2\. Thus estimated take is 16.9/100 km\2\ times 47 km\2\
times 6 days, or 48 takes.
Due to the size of the Level A harassment zone associated with
drilling, and the cryptic nature of Dall's porpoises, it is possible
Dall's porpoises may enter the Level A harassment zone undetected. It
is conservatively assumed that up to four harbor porpoises (the mean
group size from Dahlheim et al. 2009) may enter the Level A harassment
once during the duration of the project. Thus we allot the 48 takes
above to 4 Level A takes and 44 Level B takes.
Harbor Porpoise
Density was estimated for harbor porpoises in Lynn Canal by
Dahlhein et al. (2015) to be 0.2 individuals/km\2\. As noted above the
ensonified area is 47 km\2\. Thus estimated take is 0.2/km\2\ times 47
km\2\ times 6 days, or 57 takes.
Due to the size of the Level A harassment zone associated with
drilling, and the stealthy nature of harbor porpoises with no visible
blow and a low profile, it is possible harbor porpoises may enter the
Level A harassment zone undetected. Because they are most commonly
observed in pairs (Dahlheim et al. 2009), it is conservatively assumed
that one pair of harbor porpoises may enter the Level A harassment zone
every other day of pile driving. Thus we allot the 57 takes above to 6
Level A takes and 51 Level B takes.
Killer Whale
Based on the information available as discussed above, it is
conservatively estimated that 2 interactions with the average group
size of residents (33) and 2 interactions with the average group size
of transients (5) may be occur during the 6 days of the project. Thus
we expect 76 Level B takes of killer whales.
Minke Whale
There are no known occurrences of minke whales within the project
area, however since their ranges extend into the project area and they
have been observed in southeast Alaska (Dahlheim et al., 2009), it is
possible minke whales could occur near the project. It is estimated up
to one minke whale could be exposed to elevated noise levels from the
project. Therefore, 1 Level B take is proposed to be authorized.
[[Page 18209]]
Table 6--Proposed Authorized Level A and B Take and Percent of MMPA Stock Proposed to Be Taken
----------------------------------------------------------------------------------------------------------------
Proposed authorized take
Species -----------------------------------------------
Level B Level A % of stock
----------------------------------------------------------------------------------------------------------------
Humpback Whale \1\.............................................. 144 0 1.4
Minke Whale..................................................... 1 0 N/A
Killer Whale.................................................... 76 0 2.9
Harbor Porpoise................................................. 51 6 5.9
Dall's Porpoise................................................. 44 4 N/A
Harbor Seal \2\................................................. 36,180 0 8.5
Steller Sea Lion (Eastern DPS) \3\.............................. 1467 0 3.5
Steller Sea Lion (Western DPS) \3\.............................. 21 0 0.04
----------------------------------------------------------------------------------------------------------------
\1\ Distribution of proposed take by ESA status is 88 Level B takes for Hawaii DPS and 8 Level B take for Mexico
DPS.
\2\ Percent of stock taken is calculated assuming 804 unique individuals exposed, individuals are likely to be
repeatedly counted as takes because of dive times of species.
\3\ Total estimated take of Steller sea lions was 992. Distribution between the stocks was calculated assuming
1.4% Western DPS and rounding to nearest whole number.
Effects of Specified Activities on Subsistence Uses of Marine Mammals
The availability of the affected marine mammal stocks or species
for subsistence uses may be impacted by this activity. The subsistence
uses that may be affected and the potential impacts of the activity on
those uses are described below. The information from this section is
analyzed to determine whether the necessary findings may be made in the
Unmitigable Adverse Impact Analysis and Determination section.
Subsistence harvest of harbor seals and Steller sea lions by Alaska
Natives is not prohibited by the MMPA. No records exist of subsistence
harvests of whales and porpoises in Lynn Canal (Haines, 2007). The
ADF&G has regularly conducted surveys of harbor seal and Steller sea
lion subsistence harvest in Alaska and the number of Steller sea lions
taken for subsistence in this immediate area from 1992-2008, and 2012
is only two (Wolfe et al. 2013). Subsequent to the 2012 reporting year
through 2017, an estimated one to three Steller sea lions have been
taken annually outside Sitka Sound (personal communication with Lauren
Sill, ADF&G, 83 FR 52394; October 17, 2018). Based upon data for harbor
seal harvests, hunters in Southeast Alaska took from 523 to 719 harbor
seals annually in the years 1992-2008. In 2012 an estimated 595 harbor
seals were taken for subsistence uses (Wolfe et al. 2013). Seals were
harvested across the year, with peak harvests in March, May, and
October. Most recent reported data for the Juneau area indicates that
in 2012, an estimated 26 harbor seal were harvested for food (Wolfe et
al. 2013). From 2013 through 2019, Juneau area harbor seal hunting has
continued, with several cultural heritage programs teaching students
how to harvest, cut and store seal meat. However, there is no
information on take numbers from 2013-2019 (personal communication with
Lauren Sill, ADF&G).
Since there is very little sea lion hunting in the Juneau area,
short term displacement of animals from the project area is anticipated
to have no effect on abundance or availability of Steller sea lions to
subsistence hunters. Further, due to the project timing, Steller sea
lions are typically absent from the project area and it is possible
none will be displaced. The Douglas Indian Association, Sealaska
Heritage Institute, and the Central Council of the Tlingit and Haida
Indian Tribes of Alaska (Central Council) were contacted during
December 2019 to discuss this project. The Douglas Indian Association
responded that they did not see any impacts that may affect their
subsistence use. Chuck Smythe, with the Sealaska Heritage Institute,
responded indicating that there is known harbor seal hunting in the
project area. The other groups have not responded.
Construction activities at the project site would be expected to
cause only short term, non-lethal disturbance of marine mammals.
Construction activities are localized and temporary, mitigation
measures will be implemented to minimize disturbance of marine mammals
in the action area, and, the project will not result in significant
changes to availability of subsistence resources. Impacts on the
abundance or availability of either species to subsistence hunters in
the region are thus not anticipated.
Proposed Mitigation
In order to issue an IHA under Section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting the activity or other means of effecting the least
practicable adverse impact upon the affected species or stocks and
their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, we
carefully consider two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure will be effective if
implemented (probability of accomplishing the mitigating result if
implemented as planned), the likelihood of effective implementation
(probability implemented as planned), and;
(2) the practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
[[Page 18210]]
The following mitigation measures are proposed in the IHA:
Schedule: Pile driving or removal would occur during
daylight hours. If poor environmental conditions restrict visibility
(e.g., from excessive wind or fog, high Beaufort state), pile
installation would be delayed. No pile driving would occur from March 1
through May 31 to avoid peak marine mammal abundance periods and
critical foraging periods;
Pile Driving Delay/Shut-Down: For use of in-water heavy
machinery/vessel (e.g., dredge), GCHS will implement a minimum shutdown
zone of 10 m radius around the pile/vessel. For vessels, GCHS must
cease operations and reduce vessel speed to the minimum required to
maintain steerage and safe working conditions. In addition, if an
animal comes within the shutdown zone (see Table 7) of a pile being
driven or removed, GCHS would shut down. The shutdown zone would only
be reopened when a marine mammal has not been observed within the
shutdown zone for a 30-minute period. If pile driving is stopped, pile
installation would not commence if pile any marine mammals are observed
anywhere within the Level A harassment zone. Pile driving activities
would only be conducted during daylight hours when it is possible to
visually monitor for marine mammals. If a species for which
authorization has not been granted, or if a species for which
authorization has been granted but the authorized takes are met, GCHS
would delay or shut-down pile driving if the marine mammal approaches
or is observed within the Level A and/or B harassment zones. In the
unanticipated event that the specified activity clearly causes the take
of a marine mammal in a manner prohibited by the IHA, such as serious
injury or mortality, the protected species observer (PSO) on watch
would immediately call for the cessation of the specified activities
and immediately report the incident to the Chief of the Permits and
Conservation Division, Office of Protected Resources, NMFS, and NMFS
Alaska Regional Office;
Soft-start: For all impact pile driving, a ``soft start''
technique will be used at the beginning of each pile installation day,
or if pile driving has ceased for more than 30 minutes, to allow any
marine mammal that may be in the immediate area to leave before
hammering at full energy. The soft start requires GCHS to provide an
initial set of three strikes from the impact hammer at reduced energy,
followed by a 30 second waiting period, then two subsequent 3-strike
sets. If any marine mammal is sighted within the Level A shutdown zone
prior to pile-driving, or during the soft start, GCHS will delay pile-
driving until the animal is confirmed to have moved outside and is on a
path away from the Level A harassment zone or if 15 minutes have
elapsed since the last sighting; and
Other best management practices: GCHS will drive all piles
with a vibratory hammer to the maximum extent possible (i.e., until a
desired depth is achieved or to refusal) prior to using an impact
hammer and will use DTH drilling prior to using an impact hammer. GCHS
will also use the minimum hammer energy needed to safely install the
piles.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stock for
subsistence uses.
Table 7--Shutdown Zones for Each Activity Type and Stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown zone--permitted species Level B harassment
---------------------------------------------------------------------------------------------------- zone
Source Low-frequency Mid-frequency High-frequency -------------------
cetaceans cetaceans cetaceans Phocids Otariids All species
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory/Drilling.............. 80 m (265 ft)..... 7 m (25 ft)....... 120 m (395 ft).... 50 m (165 ft)..... 10 m (35 ft)...... 12.1 km (7.5
miles).
Impact Pile Driving............. 185 m (605 ft).... 10 m (35 ft)...... 220 m (720 ft).... 100 m (325 ft).... 10 m (35 ft)...... 1000 m (3280 ft).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
Visual Monitoring
Monitoring would be conducted 30 minutes before, during, and 30
minutes after pile driving 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
[[Page 18211]]
driven or removed. Pile driving activities include the time to install
a single pile or series of piles, as long as the time elapsed between
uses of the pile driving equipment is no more than thirty minutes.
A primary PSO would be placed at the project site where pile
driving would occur. The primary purpose of this observer is to monitor
and implement the Level A shutdown zones. Two additional observers
would focus on monitoring large parts of the Level B harassment zone as
well as visible parts of the Level A shutdown and harassment zones. The
locations are shown in Figure 2 of the monitoring plan. Since not all
of the Level B harassment zone will be observable by PSOs, they will
calculate take for the project by extrapolating the observable area to
the total size of the Level B harassment zone. PSOs would scan the
waters using binoculars, and/or spotting scopes, and would use a
handheld GPS or range-finder device to verify the distance to each
sighting from the project site. All PSOs would be trained in marine
mammal identification and behaviors and are required to have no other
project-related tasks while conducting monitoring. The following
measures also apply to visual monitoring:
(1) Monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable to monitor for
marine mammals and implement shutdown/delay procedures when applicable
by calling for the shutdown to the hammer operator. Qualified observers
are trained biologists, with the following minimum qualifications:
(a) Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
(b) Advanced education in biological science or related field
(undergraduate degree or higher required);
(c) Experience and ability to conduct field observations and
collect data according to assigned protocols (this may include academic
experience);
(d) Experience or training in the field identification of marine
mammals, including the identification of behaviors;
(e) Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
(f) Writing skills sufficient to prepare a report of observations
including but not limited to the number and species of marine mammals
observed; dates and times when in-water construction activities were
conducted; dates and times when in-water construction activities were
suspended to avoid potential incidental injury from construction sound
of marine mammals observed within a defined shutdown zone; and marine
mammal behavior; and
(g) Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary; and
(2) GCHS shall submit observer CVs for approval by NMFS.
A draft marine mammal monitoring report would be submitted to NMFS
within 90 days after the completion of pile driving activities, or 60
days prior to a requested date of issuance of any future IHAs for
projects at the same location, whichever comes first. It will include
an overall description of work completed, a narrative regarding marine
mammal sightings, and associated marine mammal observation data sheets.
Specifically, the report must include:
Dates and times (begin and end) of all marine mammal
monitoring;
Construction activities occurring during each daily
observation period, including how many and what type of piles were
driven or removed and by what method (i.e., impact or vibratory);
Weather parameters and water conditions during each
monitoring period (e.g., wind speed, percent cover, visibility, sea
state);
The number of marine mammals observed, by species,
relative to the pile location and if pile driving or removal was
occurring at time of sighting;
Age and sex class, if possible, of all marine mammals
observed;
PSO locations during marine mammal monitoring;
Distances and bearings of each marine mammal observed to
the pile being driven or removed for each sighting (if pile driving or
removal was occurring at time of sighting);
Description of any marine mammal behavior patterns during
obsevation, including direction of travel and estimated time spent
within the Level A and Level B harassment zones while the source was
active;
Number of individuals of each species (differentiated by
month as appropriate) detected within the monitoring zone, and
estimates of number of marine mammals taken, by species (a correction
factor may be applied to total take numbers, as appropriate;
Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting behavior of the animal, if
any;
Description of attempts to distinguish between the number
of individual animals taken and the number of incidences of take, such
as ability to track groups or individuals; and
Submit all PSO datasheets and/or raw sighting data (in a
separate file from the Final Report referenced immediately above).
If no comments are received from NMFS within 30 days, the draft
final report will constitute the final report. If comments are
received, a final report addressing NMFS comments must be submitted
within 30 days after receipt of comments.
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the IHA-holder shall report
the incident to the Office of Protected Resources (OPR) (301-427-8401),
NMFS and to the Alaska Regional Stranding Coordinator as soon as
feasible. The report must include the following information:
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive;
If available, photographs or video footage of the
animal(s); and
General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature
[[Page 18212]]
of any responses (e.g., intensity, duration), the context of any
responses (e.g., critical reproductive time or location, migration), as
well as effects on habitat, and the likely effectiveness of the
mitigation. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's implementing
regulations (54 FR 40338; September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into this
analysis via their impacts on the environmental baseline (e.g., as
reflected in the regulatory status of the species, population size and
growth rate where known, ongoing sources of human-caused mortality, or
ambient noise levels).
To avoid repetition, the discussion of our analyses applies to all
the species listed in Table 6, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. There is little information about the nature or severity of
the impacts, or the size, status, or structure of any of these species
or stocks that would lead to a different analysis for this activity.
Pile driving and drilling activities have the potential to disturb or
displace marine mammals. Specifically, the project activities may
result in take, in the form of Level A harassment and Level B
harassment from underwater sounds generated from pile driving and DTH
drilling. Potential takes could occur if individuals of these species
are present in the ensonified zone when these activities are underway.
The takes from Level A and Level B harassment would be due to
potential behavioral disturbance, TTS, and PTS. No mortality is
anticipated given the nature of the activity and measures designed to
minimize the possibility of injury to marine mammals. Level A
harassment is only authorized for Dall's porpoise and harbor porpoise.
The potential for harassment is minimized through the construction
method and the implementation of the planned mitigation measures (see
Proposed Mitigation section).
Behavioral responses of marine mammals to pile driving at the
project site, if any, are expected to be mild and temporary. Marine
mammals within the Level B harassment zone may not show any visual cues
they are disturbed by activities (as noted during modification to the
Kodiak Ferry Dock) or could become alert, avoid the area, leave the
area, or display other mild responses that are not observable such as
changes in vocalization patterns. Given the short duration of noise-
generating activities per day and that pile driving would occur on no
more than 4 days, any harassment would be temporary. In addition, GCHS
would not conduct pile driving during the spring eulachon and herring
runs, when marine mammals are in greatest abundance and engaging in
concentrated foraging behavior. There are no other areas or times of
known biological importance for any of the affected species.
In addition, although some affected humpback whales and Steller sea
lions may be from a DPS that is listed under the ESA, it is unlikely
that minor noise effects in a small, localized area of habitat would
have any effect on the stocks' ability to recover. In combination, we
believe that these factors, as well as the available body of evidence
from other similar activities, demonstrate that the potential effects
of the specified activities will have only minor, short-term effects on
individuals. The specified activities are not expected to impact rates
of recruitment or survival and will therefore not result in population-
level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
No mortality is anticipated or authorized;
Authorized Level A harassment would be very small amounts
and of low degree for two cryptic species;
GCHS would avoid pile driving during peak periods of
marine mammal abundance and foraging (i.e., March 1 through May 31
eulachon and herring runs);
GCHS would implement mitigation measures such as vibratory
driving piles to the maximum extent practicable, soft-starts, and shut
downs; and
Monitoring reports from similar work in Alaska have
documented little to no effect on individuals of the same species
impacted by the specified activities.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Section 101(a)(5)(D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so, in practice, where estimated numbers are
available, NMFS compares the number of individuals taken to the most
appropriate estimation of abundance of the relevant species or stock in
our determination of whether an authorization is limited to small
numbers of marine mammals. Additionally, other qualitative factors may
be considered in the analysis, such as the temporal or spatial scale of
the activities.
The amount of take NMFS proposes to authorize is less than one-
third of any stock's best population estimate. These are all likely
conservative estimates because we assume all takes are of different
individual animals which is likely not the case, especially for harbor
seals which have the largest take. The Alaska stock of Dall's porpoise
has no official NMFS abundance estimate as the most recent estimate is
greater than eight years old. Nevertheless, the most recent estimate
was 83,400 animals and it is highly unlikely this number has
drastically declined. Therefore, the 48 authorized takes of this stock
clearly represent small numbers of this stock. The Alaska stock of
minke whale has no stock-wide abundance estimate. The stock ranges from
the Bering and Chukchi seas south through the Gulf of Alaska. Surveys
in portions of the range have estimated abundances of 2,020 on the
eastern Bering Sea shelf and 1,233 from the Kenai Fjords in the Gulf of
Alaska to the central Aleutian Islands. Thus there appears to be
thousands of animals at least in the stock and clearly the 1 authorized
takes of this stock represent small numbers of this stock.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals will be taken relative to the population size
of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR
[[Page 18213]]
216.103 as an impact resulting from the specified activity: (1) That is
likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) Placing physical barriers
between the marine mammals and the subsistence hunters; and (2) That
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
As discussed above in the subsistence uses section, subsistence
harvest of harbor seals and other marine mammals is rare in the area
and local subsistence users have not expressed concern about this
project. All project activities will take place within the Favorite
Channel area where subsistence activities do not generally occur. The
project also will not have an adverse impact on the availability of
marine mammals for subsistence use at locations farther away, where
these construction activities are not expected to take place. Some
minor, short-term harassment of the harbor seals and Steller sea lions
could occur, but any effects on subsistence harvest activities in the
region will be minimal, and not have an adverse impact.
Based on the effects and location of the specified activity, and
the mitigation and monitoring measures, NMFS has preliminarily
determined that there will not be an unmitigable adverse impact on
subsistence uses from GCHS's planned activities.
Endangered Species Act (ESA)
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally, in this case with the Alaska Region Protected
Resources Division Office, whenever we propose to authorize take for
endangered or threatened species.
NMFS is proposing to authorize take of Western DPS Steller sea lion
(Eumetopias jubatus) and Mexico DPS of humpback whales (Megaptera
novaeangliae), 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
will conclude the ESA consultation prior to reaching a determination
regarding the proposed issuance of the authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to GCHS for conducting the Sentinel Island Moorage Float
project near Juneau, Alaska between July 20, 2020 and July 19, 2021,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the proposed IHA can be found
at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this Notice of Proposed IHA for the proposed
Sentinel Island Moorage Float project. We also request at this time
comment on the potential renewal of this proposed IHA as described in
the paragraph below. Please include with your comments any supporting
data or literature citations to help inform decisions on the request
for this IHA or a subsequent Renewal IHA.
On a case-by-case basis, NMFS may issue a one-year Renewal IHA
following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical, or nearly
identical, activities as described in the Detailed Description of
Specific Activity section of this notice is planned or (2) the
activities as described in the Detailed Description of Specific
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
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
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: March 27, 2020.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2020-06787 Filed 3-31-20; 8:45 am]
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