Takes of Marine Mammals Incidental To Specified Activities; Taking Marine Mammals Incidental to Alaska Marine Lines Lutak Dock Project, Haines, Alaska, 65117-65133 [2019-25642]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 84, Number 228 (Tuesday, November 26, 2019)]
[Notices]
[Pages 65117-65133]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-25642]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XR066]


Takes of Marine Mammals Incidental To Specified Activities; 
Taking Marine Mammals Incidental to Alaska Marine Lines Lutak Dock 
Project, Haines, 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 Alaska Marine Lines, Inc. 
(AML) for authorization to take marine mammals incidental to Lutak Dock 
project in Haines, 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 December 
26, 2019.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Dwayne Meadows, Ph.D., Office of 
Protected Resources, NMFS, (301) 427-8401. Electronic copies of the 
application and supporting documents, as well as a list of the 
references cited in this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

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

[[Page 65118]]

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 9 July 2019, NMFS received a request from AML for an IHA to take 
marine mammals incidental to Lutak Dock project in Haines, Alaska. The 
application was deemed adequate and complete on October 23, 2019. AML's 
request is for take of seven species of marine mammals by Level B 
harassment and/or Level A harassment. Neither AML 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 demolition, re-construction, and 
improvement of a commercial barge cargo dock in Lutak Inlet near 
Haines, Alaska adjacent to the Haines Ferry Terminal. The project 
includes the following in-water components: Removal (by vibratory 
pulling or cutting off at the mudline) of 12 steel pipe piles (16'' 
diameter) of two berthing dolphins associated with the existing steel 
cargo bridge; fill 4,000 yards of gravel and 1,000 yards of riprap to 
construct a causeway below the new dock; installing below mean high 
water (MHW) a 46-foot long by 15-foot wide steel float; installing 
below MHW (using vibratory or impact pile driving or down-the-hole 
(DTH) drilling) four 24-inch diameter steel pipe piles to construct two 
float strut dolphins, six 36-inch diameter steel pipe piles to 
construct two breasting dolphins; and construction of a 40-foot wide by 
40-foot long, pile supported (three 30-inch diameter steel pipe piles), 
concrete abutment within the proposed causeway to support a 120-foot 
long by 24-foot wide steel bridge over navigable waters.
    The pile driving or DTH drilling can result in take of marine 
mammals from sound in the water which results in behavioral harassment 
or auditory injury. The footprint of the project is approximately one 
square mile around the project site. The project will take no more than 
8 days of pile-driving/pulling or DTH drilling.

Dates and Duration

    The work for which take will be authorized will occur between June 
15, 2020 and June 14, 2021. The duration of the pile driving would be 
from approximately mid- to late June through October 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 removal and driving would begin no sooner than 30 
minutes after sunrise and would end 30 minutes prior to sunset to allow 
for marine mammal monitoring.

Specific Geographic Region

    The project site is located at Lutak Dock near the mouth of Lutak 
Inlet, approximately 4 miles north of Haines in northern southeastern 
Alaska. The Chilkat, Chilkoot, Lutak, and Taiya inlets compose the 
northern part of Lynn Canal (see Figure 1-1 in application). The 
project area is situated on the shore of Lutak Inlet between the 
Chilkoot and Chilkat rivers. Lutak Inlet is a glacial scoured fjord 
with an estuary that is five miles long and one mile wide from Tanani 
Point and Taiya Point to its confluence with the Chilkoot River. The 
Inlet has depths generally less than 275 feet, with depths at the mouth 
of about 400 feet (Haines, 2007).
    Several seasonally available prey species are abundant and densely 
aggregated within the project area. In Southeast Alaska, spawning of 
eulachon (Thaleichtys pacificus) (Marston et al., 2002; Sigler et al., 
2004) and herring (Clupea pallasii) (Womble et al., 2005) play an 
important role in the seasonal foraging ecology of sea lions in the 
area (Marston et al., 2002; Sigler et al., 2004; Womble et al., 2005; 
Womble and Sigler, 2006). Eulachon are anadromous smelt that spawn 
primarily from March to May (Marston et al., 2002; Womble, 2003).
    The underwater acoustic environment in the project area is 
dominated by ambient noise from day-to-day ferry terminal, port, and 
vessel activities. Haines Borough operates two harbor facilities 
(Portage Cove and Letnikof Cove), a float moored at Swanson Harbor in 
Couverden, two docks (Lutak and Port Chilkoot), and three boat launch 
ramps (at Lutak Dock, Portage Cove and Letnikof Cove) (Haines Borough 
Comprehensive Plan (2012)). Lutak Dock is the second busiest port for 
the Alaska Marine Highway System. Delta Western (tug and barge 
business) also operates out of this area.

Detailed Description of Specific Activity

    An existing steel cargo bridge with steel floats and associated 
berthing dolphins currently used for cargo barge operations would be 
removed. The structure is currently supported by twelve 16-inch 
diameter steel piles. These 12 piles would be removed utilizing a 
crane-mounted vibratory hammer located on a barge or on land. If piles 
cannot be removed using vibratory methods, they would be cut at the 
mudline using an underwater shielded metal-arc cutter or left in place. 
Removal of the existing piles is expected to take one day.
    To facilitate the project, a causeway will be constructed below the 
new dock using approximately 4,000 yards of gravel and 1,000 yards of 
riprap fill, and a 46-foot long by 15-foot wide steel float will be 
installed below MHW. Neither of these project components are expected 
to impact marine mammals, their habitat, or their subsistence use, so 
these components will not be considered further.
    To support the new 120 foot by 24 foot long steel bridge and 
associated dolphins, four 24-inch diameter and six 36-inch diameter 
steel pipes would be driven into the marine sand and gravel at the 
project location. Three additional 30-inch diameter steel pipes would 
be installed to support a concrete abutment (see Figure 1-2 of 
application). The pipe piles would be installed to a depth of 40 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 700 strikes would be needed to drive each of the piles to a 
sufficient depth which may require about 15 minutes of hammering. It is 
estimated that about 3 hours (maximum) would be required to drive each 
pile and they would be proofed the same day.

[[Page 65119]]

    Bedrock may be encountered before the full required pile depth is 
achieved. Where bedrock is present, piles would be installed using both 
vibratory and DTH drilling. Initially a vibratory hammer would be used 
to drive the sediment until bedrock is reached (~60 minutes). A DTH 
hammer (e.g., Numa) would be used to drill and socket the pile into 
bedrock. This could take up to an additional 180 minutes.
    In summary, vibratory and impact driving would take up to three 
hours for each pile. Multiple piles would not be concurrently driven. 
Under the best-case scenario, using solely vibratory and impact 
driving, five piles would be set in a day. If DTH drilling is needed, 
it would be used the same day following vibratory driving, with the 
worst case scenario being only two piles could be set and drilled in 
one day. Therefore, the duration of drilling activity for the 13 piles 
could be as short as three days or as long as seven days. Thus in the 
worst case, the entire project would take a total of eight 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 
Haines, 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 (2016). 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 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)          PBR          SI \3\
                                                                                                                \2\
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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         -; N (Hawaii DPS)...  10,103 (0.3, 7,890,   83..............         25
                                     novaeangliae.          Pacific.             T,D,Y (Mexico DPS)..   2006).               N/A.............        N/A
                                                           Central North                               3264................
                                                            Pacific.
    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.....                        2347................  24..............          1
                                                           Northern Resident...  -; Y................  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):
    California sea lion...........  Zalophus               U.S.................  -; N................  257,606 (N/           14,011..........       >320
                                     californianus.                                                     A,233,515, 2014).
    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).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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.

[[Page 65120]]

 
\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.
\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, all seven species 
(with ten 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.
    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.

Sperm Whale

    Sperm whales (Physeter macrocephalus) are considered extralimital 
in the project area. However, on March 20, 2019, a dead sperm whale was 
found washed up in Lynn Canal. Based on NOAA's Whale alert system (NOAA 
2019), the Alaska State Ferry reported seeing four sperm whales in 
December 2018 off False Point Retreat, and two near Point Howard in 
lower Lynn Canal early in March 2019. Despite these recent sightings, 
sperm whales are very rare in the area. Due to the low probability of 
these species occurring in the project area, exposure of these 
cetaceans to project impacts is considered unlikely and take is not 
requested for these species and they are not considered further.

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 Chilkoot Inlet and have been observed 
infrequently near the mouth of Lutak Inlet during the spring eulachon 
and herring runs; they generally vacate the area by July to feed on 
aggregations of herring in lower Lynn Canal. In recent years, however, 
a few whales have been observed at the entrance to Taiya Inlet 
throughout the fall months (NMFS 2019) and at the mouth of Lutak Inlet 
(K. Hastings, (Alaska Department of Fish and Game (ADF&G), personal 
communication). Hastings observed from one to three humpback whales at 
Gran Point in May of 2015 and 2018. Individuals have been observed in 
the same area intermittently throughout the summer months, but most 
whales move further south and are absent from the Action Area during 
summer.
    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 two 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 extreme northern Lynn Canal in July 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. AML 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. Local abundances were calculated from data 
provided by K. Hastings (ADF&G), who reported humpback whales at Gran 
Point in 2015 and 2018.

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 northern parts of Lynn Canal 
(Dahlheim et al., 2009). However, minke whales forage on schooling fish 
and may rarely enter the project area in Upper Lynn Canal. 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).
    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. 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 occurrence of 
transient killer whales in Upper Lynn Canal increases in summer, with 
lower numbers observed in spring and fall.

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. The Alaska stock is the only Dall's porpoise 
stock found in Alaska waters.

[[Page 65121]]

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 Upper Lynn Canal, though they have been 
observed as far north as Haines during the summer months (Dahlheim et 
al., 2015).

California Sea Lion

    Several California sea lions (Zalophus californianus) were observed 
at Gran Point in May 2005 (K. Hastings, ADF&G); however they have not 
been observed since that date and will not be considered further in 
this analysis.

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 in Chilkoot Inlet; they seasonally occupy Lutak 
Inlet. They follow spring foraging runs of eulachon into Lutak Inlet up 
to the mouth of the Chilkoot River, then move farther south to forage 
on herring in late-summer and fall. Salmon increase in importance as 
prey for sea lions from late-October and December in the Chilkat River. 
The closest haulout to the project area is Gran Point, about 14 miles 
southeast. During the spring eulachon run, a temporary seasonal haulout 
site is also located on Taiya Point at the southern tip of Taiya Inlet 
(approximately 3.1 miles from the project site).
    Branded individuals from the Western DPS have been observed at the 
Gran Point haulout. Three individual Western DPS sea lions were 
observed repeatedly at Gran Point from 2003 through 2012 (NMFS, 2013). 
The most recent assessment of branded or marked Western DPS sea lions 
at the Gran Point haul out was provided by Hastings (ADF&G, personal 
communication) and Jemison et al. (2018). The percentage of Western DPS 
animals in the recent time period was 1.7 percent; for the rest of this 
analysis we conservatively assume that 2 percent of the Steller sea 
lions in the project area are from the Western DPS.
    Data from almost two decades of surveys and research on 
distribution, abundance and seasonal foraging behavior of Steller sea 
lions from the Gran Point haul out are used in to estimate take. These 
data, with sightings through 2018, have been provided through personal 
communication to the applicants with key marine mammal researchers in 
the region (K. Hastings ADF&G; Tom Gelatt, NMFS Alaska Fisheries 
Science Center). The average monthly densities for Steller sea lions at 
Gran Point were estimated using this database as a proxy for the 
monthly abundance of sea lions within the project area.

Harbor Seal

    Harbor seals (Phoca vitulina) inhabit coastal and estuarine waters 
off Alaska. They haul out on rocks, reefs, beaches, and drifting 
glacial ice. They are opportunistic feeders and often adjust their 
distribution to take advantage of locally and seasonally abundant prey 
(Womble et al., 2009, Allen and Angliss, 2015). Harbor seals occurring 
in the project area belong to the Lynn Canal/Stephens Passage (LC/SP) 
stock. Harbor seals are common in Lutak Inlet and in Chilkat Inlet 
where there is a small haulout at Pyramid Island. They are abundant in 
the Chilkat and Chilkoot rivers in late fall and winter during spawning 
runs of salmon (Onchorhynchus spp.) and in the spring (mid-March 
through mid-May) when eulachon (Thaleichtys pacificus) are present. As 
many as about 100 individuals have been observed actively feeding in 
Lutak Inlet near the mouth of the Chilkoot River, and at up-river 
locations during these fish runs (K. Hastings ADF&G, 2016 and J. 
Womble, 2016 personal communication).

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 2.

           Table 2--Marine Mammal Hearing Groups (NMFS, 2018)
------------------------------------------------------------------------
               Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen        7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,     150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true         275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus cruciger
 & L. australis).
Phocid pinnipeds (PW) (underwater) (true    50 Hz to 86 kHz.
 seals).

[[Page 65122]]

 
Otariid pinnipeds (OW) (underwater) (sea    60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
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, Dall's porpoise and Kogia spp.).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take by Incidental Harassment section 
later in this document includes a quantitative analysis of the number 
of individuals that are expected to be taken by this activity. The 
Negligible Impact Analysis and Determination section considers the 
content of this section, the Estimated Take by Incidental Harassment 
section, and the Proposed Mitigation section, to draw conclusions 
regarding the likely impacts of these activities on the reproductive 
success or survivorship of individuals and how those impacts on 
individuals are likely to impact marine mammal species or stocks.

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 removal, 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 down-the-hole drill is a 
drill bit that drills through the bedrock using a pulse mechanism that 
functions at the bottom of the hole. This pulsing bit breaks up rock to 
allow removal of debris and insertion of the pile. The head extends so 
that the drilling takes place below the pile. The pulsing sounds 
produced by the down-the-hole drilling method are continuous, however 
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.
    The likely or possible impacts of AML's proposed activity on marine 
mammals could involve both non-acoustic and acoustic stressors.

[[Page 65123]]

Potential non-acoustic stressors could result from the physical 
presence of the equipment and personnel; however, any impacts to marine 
mammals are expected to primarily be acoustic in nature. Acoustic 
stressors include effects of heavy equipment operation during pile 
installation and removal and drilling.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal and DTH drilling is the 
primary means by which marine mammals may be harassed from AML's 
specified activity. In general, animals exposed to natural or 
anthropogenic sound may experience physical and psychological effects, 
ranging in magnitude from none to severe (Southall et al., 2007). 
Generally, exposure to pile driving and drilling noise has the 
potential to result in auditory threshold shifts and behavioral 
reactions (e.g., avoidance, temporary cessation of foraging and 
vocalizing, changes in dive behavior). Exposure to anthropogenic noise 
can also lead to non-observable physiological responses such an 
increase in stress hormones. Additional noise in a marine mammal's 
habitat can mask acoustic cues used by marine mammals to carry out 
daily functions such as communication and predator and prey detection. 
The effects of pile driving and drilling noise on marine mammals are 
dependent on several factors, including, but not limited to, sound type 
(e.g., impulsive vs. non-impulsive), the species, age and sex class 
(e.g., adult male vs. mom with calf), duration of exposure, the 
distance between the pile and the animal, received levels, behavior at 
time of exposure, and previous history with exposure (Wartzok et al., 
2004; Southall et al., 2007). Here we discuss physical auditory effects 
(threshold shifts) followed by behavioral effects and potential impacts 
on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the 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

[[Page 65124]]

area and not remaining for extended periods of time, the potential for 
TS declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal and drilling also has the potential to behaviorally disturb 
marine mammals. Available studies show wide variation in response to 
underwater sound; therefore, it is difficult to predict specifically 
how any given sound in a particular instance might affect marine 
mammals perceiving the signal. If a marine mammal does react briefly to 
an underwater sound by changing its behavior or moving a small 
distance, the impacts of the change are unlikely to be significant to 
the individual, let alone the stock or population. However, if a sound 
source displaces marine mammals from an important feeding or breeding 
area for a prolonged period, impacts on individuals and populations 
could be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; 
NRC, 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul-out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound 
are highly variable and context-specific and any reactions depend on 
numerous intrinsic and extrinsic factors (e.g., species, state of 
maturity, experience, current activity, reproductive state, auditory 
sensitivity, time of day), as well as the interplay between factors 
(e.g., Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 
2007; Weilgart, 2007; Archer et al., 2010). Behavioral reactions can 
vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
In general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. Please see Appendices B and C of Southall et 
al. (2007) for a review of studies involving marine mammal behavioral 
responses to sound.
    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 AML'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. Lutak 
Dock and the Haines 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 removal and DTH drilling that have the potential to cause 
behavioral harassment, depending on their distance from pile driving 
activities. Cetaceans are not expected to be exposed to airborne sounds 
that would result in harassment as defined under the MMPA.
    Airborne noise would primarily be an issue for pinnipeds that are 
swimming or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. We recognize that 
pinnipeds in the water could be exposed to airborne sound that may 
result in behavioral harassment when looking with their heads above

[[Page 65125]]

water. Most likely, airborne sound would cause behavioral responses 
similar to those discussed above in relation to underwater sound. For 
instance, anthropogenic sound could cause hauled-out pinnipeds to 
exhibit changes in their normal behavior, such as reduction in 
vocalizations, or cause them to temporarily abandon the area and move 
further from the source. However, these animals would previously have 
been `taken' because of exposure to underwater sound above the 
behavioral harassment thresholds, which are in all cases larger than 
those associated with airborne sound. Thus, the behavioral harassment 
of these animals is already accounted for in these estimates of 
potential take. Therefore, we do not believe that authorization of 
incidental take resulting from airborne sound for pinnipeds is 
warranted, and airborne sound is not discussed further here.

Marine Mammal Habitat Effects

    AML's construction activities at Lutak Dock 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 Lutak Inlet 
where both fish and mammals occur and could affect foraging success.
    Construction activities are of short duration and would likely have 
temporary impacts on marine mammal habitat through increases in 
underwater and airborne sound. These sounds would not be detectable at 
Gran Point.
    In-water pile driving, pile removal, 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. AML 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 Lutak Dock area) and does not include 
any BIAs or ESA-designated critical habitat. Pile installation/removal 
and drilling may temporarily increase turbidity resulting from 
suspended sediments. Any increases would be temporary, localized, and 
minimal. AML 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 and removal at the project site would not obstruct movements or 
migration of marine mammals.
    Avoidance by potential prey (i.e., fish) of the immediate area due 
to the temporary loss of this foraging habitat is also possible. The 
duration of fish avoidance of this area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity in Lynn Canal and 
the project would occur outside the peak eulachon 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 8 days of pile drilling/removal. 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 he