Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to In-Water Demolition and Construction Activities Associated With a Harbor Improvement Project in Statter Harbor, Alaska, 52394-52416 [2018-22604]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 83, Number 201 (Wednesday, October 17, 2018)]
[Notices]
[Pages 52394-52416]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-22604]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG506


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to In-Water Demolition and 
Construction Activities Associated With a Harbor Improvement Project in 
Statter Harbor, 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 the City of Juneau for 
authorization to take marine mammals incidental to harbor improvement 
projects in Statter Harbor, 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 November 
16, 2018.

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/node/23111 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: Sara Young, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems 
accessing these documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain

[[Page 52395]]

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 such 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 such takings are set forth.
    The NDAA (Pub. L. 108-136) removed the ``small numbers'' and 
``specified geographical region'' limitations indicated above and 
amended the definition of ``harassment'' as it applies to a ``military 
readiness activity.'' The definitions of all applicable MMPA statutory 
terms cited above are included in the relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or 
mortality) of the Companion Manual for NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for 
significant impacts on the quality of the human environment and for 
which we have not identified any extraordinary circumstances that would 
preclude this categorical exclusion. Accordingly, NMFS has 
preliminarily determined that the issuance of the proposed IHA 
qualifies to be categorically excluded from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On February 12, 2018, NMFS received a request from the City of 
Juneau for an IHA to take marine mammals incidental to harbor 
improvement projects in Statter Harbor, Alaska. The original 
application covered three years of potential work and was revised to 
one year of work on March 9, 2018. A series of exchanges regarding 
acoustic analyses continued until a meeting was held on June 21, 2018. 
An additional revision was received on August 8, 2019. The application 
was deemed adequate and complete on September 18, 2018. The City of 
Juneau's request is for take of a small number of harbor seal, harbor 
porpoise, humpback whale, and Steller sea lion by Level B harassment 
and Level A harassment. Neither the City of Juneau nor NMFS expects 
serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    The harbor improvements described in the application include 
demolition and disposal of the existing boat launch ramp and timber 
haulout pier, dredging of the planned harbor basin with offshore 
disposal, excavation of bedrock within the basin by blasting from a 
temporary fill pad, and construction of a mechanically stabilized earth 
(MSE) wall.

Dates and Duration

    Work is expected to occur between January 1, 2019 and December 31, 
2019. The expected allocation of days for each activity is as follows: 
Two to ten days of vibratory pile removal, 30-45 days of dredging and 
dredge disposal, 15 days of in-water fill placement and removal, and 
two days of blasting. In winter months, shorter 8-hour to 10-hour 
workdays in available daylight are anticipated. To be conservative, 12-
hour work days were used to analyze construction noise. The daily 
construction window for blasting and dredging will begin no sooner than 
30 minutes after sunrise to allow for initial marine mammal monitoring 
to take place and will end 30 minutes before sunset to allow for post-
activity monitoring.

Specific Geographic Region

    The proposed activities would occur at Statter Harbor in Auke Bay, 
Alaska which is in the southeast portion of the state. See Figures 1 
and 4 in the application for detailed maps of the project area. Statter 
Harbor is located at the most northeasterly point of Auke Bay.

Detailed Description of Specific Activity

    Demolition and Disposal--Work proposed for 2019 includes demolition 
and disposal of the existing 16-foot (ft) (4.9-meter (m)) by 200-ft 
(61-meter) concrete boat launch ramp and planks, an 8-ft (2.4-m) by 
240-ft (73.2-m) boarding float, four 12.75-inch (in) (3.2-decimeter) 
diameter steel pipe piles, 1,152 square feet (ft) (107.0 square m) of 
timber boat haulout pier, and 16 12-in to 16-in creosote-treated timber 
piles.
    Demolition of the existing timber boat haulout pier and boat launch 
ramp will be performed with track excavators, loaders, cranes, barges, 
crane dead-pulling (preferred method), vibratory hammer (if needed), 
various hand tools, and labor forces. Existing piles will be removed 
via dead-pulling with a crane if possible, or, if not, a vibratory 
hammer will be used. Vibratory pile removal will generally consist of 
clamping the vibratory hammer to the pile and vibrating the hammer 
while extracting to a point where the pile is temporarily secured and 
removal can be completed with crane line rigging under tension. The 
pile is then completely removed from the water by hoisting with crane 
line rigging and placing on the uplands or deck of the barge. The 
applicant will dispose of demolished items in accordance with all 
Federal, state, and local regulations.
    Based on the characterization of work described below, we expect 
take of marine mammals may result from some combination of vibratory 
pile removal, dredging, and blasting activities.

Dredging and Dredge Disposal

    The project includes 24,300 cubic yards (yd\3\)(18,578.7 cubic 
meters (m\3\)) of dredging in the existing harbor. When the material is 
removed from the ground it will bulk up in the barge due to increased 
water content and fluff. To account for this a conservative bulking 
factor of 1.25 was applied to the dredged volume, resulting in up to 
30,375 yd\3\(23,223.4m\3\) of material to be disposed. Dredging will be 
performed by either an excavator or a crane with clamshell from a flat 
deck or derrick

[[Page 52396]]

barge. The barge will be fixed in place to allow the excavator access 
to an area and periodically repositioned to gain access to new areas.
    Once material is removed from the seafloor, it will be placed into 
a second belly dump dredge barge where the material will be dewatered 
and then be towed by a tug to the disposal site to be deposited. The 
target location for disposal of material was provided to the applicant 
by the Alaska Department of Fish and Game (ADF&G) just outside of the 
harbor at latitude 58[deg]22'22.08'' N and 134[deg]39'49.32'' W. Based 
on the nature of dredge disposal activity, substrate placed on a small 
barge and towed to a disposal site, we do not consider dredge disposal 
an activity that could result in take of marine mammals and do not 
consider it further. Because the dredging activity is producing sound 
underwater at levels likely audible to marine mammals and the sound 
source is concentrated underwater in a region with resident marine 
mammals it has the potential harass marine mammals and was considered 
further in our analysis.
Blasting and Excavation
    A geotechnical investigation including borehole samples and test 
probing was performed by PND Engineers in 2016 and revealed shallow 
bedrock within the harbor basin. The design depth necessary for safe 
navigation is 16 ft (4.9 m) below mean lower low water (MLLW) with an 
additional 1-ft (0.3-m) considered as potential additional depth needed 
to dredge, also termed overdredge allowance. Test probing showed that 
the top-of-rock elevations within the dredge basin range from 
approximately 4 ft below MLLW to depths greater than the design 
elevation (17 ft (5.2 m) below MLLW with overdredge allowance).
    During construction the dredging will be conducted first to remove 
the overburden from the bedrock. A survey will then be conducted to 
determine the exact extent of bedrock to be removed. The estimated 
amount of rock excavation is 1,761 yd\3\(2,000 yd\3\(1,529.1 m\3\) 
permitted volume to account for uncertainty) based on preconstruction 
surveys. Temporary fill to confine the blast will be placed using 
conventional construction equipment. A fill is poured over the area 
where blasting is planned and then the hole for the charges are made 
beginning in the fill layer. Approximately half of the fill for this 
temporary pad will be placed above the water line.
    Alaska Seismic and Environmental prepared a General Blast Plan and 
Analysis and sound pressure level (SPL) and sound exposure level (SEL) 
Isopleth Distances report (Appendix C of the application) detailing the 
bedrock removal plan and how the exclusion zones for each hearing group 
were determined. The selected methodology for the blast is to perform 
two blasts, one per day on two separate days. Each blast will be 
approximately one (1) second in duration. Both blasts will consist of 
many detonations separated by some small number of milliseconds delay. 
The number of charges will vary depending on conditions after 
overburden is removed but is anticipated to be between 50 and 75 holes 
with charges per blast. Individual charge size will depend on 
conditions after holes are drilled; maximum charge size (explosive 
weight) detonated per each 8-millisecond delay period will be limited 
to 93.5 pounds (42.4 kilograms).
    Individual charge amounts and other hole-loading details will be 
determined by the contractor's blaster-in-charge and blasting 
consultant after holes are drilled. This allows for safe and 
appropriate loading decisions to be made based on rock features such as 
voids, seams, fractures, and other discontinuities encountered during 
drilling.
    After blasting, the temporary fill will be removed with excavators, 
loaded into dump trucks, and stockpiled in the uplands to be reused 
during the MSE wall construction. The blasted material will be 
excavated, separated from the temporary fill, and hauled offsite to an 
uplands disposal site.

MSE Wall In-Water Fill Placement and Removal

    The MSE wall will be constructed with track excavators, loaders, 
vibratory drum rollers, dump trucks, various hand tools, and labor 
forces. Excavated material will be placed into dump trucks and hauled 
offsite. The concrete retaining wall blocks will be set in place one 
course at a time. Imported fill will be delivered by dump truck, spread 
behind the blocks in lifts, and compacted with vibratory rollers to 
meet design grades and compaction requirements. A layer of geotextile 
fabric will be placed behind the wall on the compacted fill with each 
course of blocks. A total of 6,800 yd\3\ (5,199 m\3\) of shot rock 
material will be placed below the high tide line (HTL) behind the MSE 
wall.
    A 5-ft (1.5-m) thick armored dredge basin slope will require an 
additional 650 yd\3\(497 m\3\) of armor rock material, and a lower 2-ft 
(0.6-m) thick slope will require an additional 1,350 yd\3\(1,032.1 
m\3\) of material. Total fill material placed below the HTL is not 
expected to exceed 8,800 yd\3\(6,728.1 m\3\). All work in intertidal 
zones will be performed during low tides so that all material will be 
placed above current water levels. Because all material will be placed 
above current water levels, we do not expect take of marine mammals 
from this activity.
    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

    Seven species of marine mammal have been documented in southeast 
Alaska waters in the vicinity of Statter Harbor. These species are: 
harbor seal, harbor porpoise, Dall's porpoise, killer whale, humpback 
whale, minke whale, and Steller sea lion. Of these species, only three 
are known to occur in Statter Harbor: harbor seal, Steller sea lion, 
and humpback whale.
    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 (SAR; https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports) 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 
Statter Harbor 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 (2017). 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

[[Page 52397]]

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 Region Draft 2018 SAR (Muto et al, 2018). All values presented 
in Table 1 are the most recent available at the time of publication and 
are available in the Draft 2018 SAR (Muto et al, 2018).

                                             Table 1--Species With the Potential to Occur in Statter Harbor
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                                                                                         ESA/MMPA status;    Stock abundance (CV,
             Common name                  Scientific name               Stock             Strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals)
    Humpback whale..................  Megaptera noveangliae..  Central North Pacific..  E,D,Y               10,103 (0.3, 7,891,            83         26
                                                                                                             2006).
    Minke whale.....................  Balaenoptera             Alaska.................  -; N                N/A...................        Und          0
                                       acutorostrata.
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                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae
    Killer whale....................  Orcinus orca...........  Northern Resident......  -; N                261 (N/A, 261, 2011)..       1.96          0
    Killer whale....................  Orcinus orca...........  Gulf of Alaska           -; N                587 (N/A, 587, 2012)..       5.87          1
                                                                transient.
    Killer whale....................  Orcinus orca...........  West Coast Transient...  -; N                243 (N/A, 243, 2009)..        2.4          0
Family Phocoenidae (porpoises)
    Harbor porpoise.................  Phocoena phocoena......  Southeast Alaska.......  -; Y                975 (0.14, 872, 2012).        8.7         34
    Dall's porpoise.................  Phocoenoides dalli.....  Alaska.................  -; N                83,400 (0.097, N/A,           Und         38
                                                                                                             1991).
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                                                         Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
 sea lions)
    Steller sea lion................  Eumetopias jubatus.....  Western DPS............  E/D; Y              54,267 (N/A; 54,267,          326        252
                                                                                                             2017).
    Steller sea lion................  Eumetopias jubatus.....  Eastern DPS............  T/D; Y              41,638 (N/A, 41,638,         2498        108
                                                                                                             2015).
Family Phocidae (earless seals)
    Harbor seal.....................  Phoca vitulina.........  Lynn Canal.............  -; N                9,478 (N/A, 8,605,            155         50
                                                                                                             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: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
Note: Italicized species are not expected to be taken or proposed for authorization.

    All species that could potentially occur in the proposed survey 
areas are included in Table 1. It is unlikely the species italicized 
above in Table 1 are likely to venture far enough into the harbor to 
enter the acoustic isopleths where we expect take to occur. The spatial 
occurrence of minke whale and Dall's porpoise is such that take is not 
expected to occur, and they are not discussed further beyond the 
explanation provided here. While these species have been sighted in 
southeast Alaska more broadly, these sightings have been recorded for 
areas closer to the ocean. Auke Bay is separated from the Pacific by 
multiple barrier islands and Statter Harbor is located in the most 
inland section of the bay, making the occurrence of species 
infrequently sighted farther seaward even less likely. Killer whales 
are not known to occur frequently in Auke Bay, although they have been 
sighted infrequently, with no obvious temporal pattern to the 
sightings. While it is possible killer whales could enter Auke Bay 
during work, it is unlikely they would continue as far inland as 
Statter Harbor. If killer whales did venture into Statter Harbor to a 
distance where acoustic exposure would be a concern, they would be 
easily identifiable to observers stationed in the harbor for mitigation 
and monitoring purposes and a shutdown would be ordered. Therefore, 
take of killer whales from these activities is unlikely to occur and 
they are not considered further in this document. The work proposed in 
Statter Harbor is in a very sheltered and inland harbor with a 
consistent sightings record of the three species considered further: 
Steller sea lion, humpback whale, and harbor seal. Harbor porpoise, 
while infrequently sighted near Statter Harbor, are considered further 
as their fast swim speeds and small size make detection to implement 
mitigation measures difficult. The species for which take is 
anticipated are described below.

Humpback whale

    Humpbacks that breed around the main Hawaiian Islands have been 
observed in summer feeding grounds throughout the North Pacific. The 
majority of the humpbacks found in Southeast Alaska and northern 
British Columbia have migrated from Hawaii for foraging opportunities 
and belong to the Hawaii DPS (Bettridge et al, 2015). Wade et al. 
(2016) estimated that 93.9 percent of the humpbacks encountered in 
Southeast Alaska and Northern British Columbia are from the Hawaii DPS, 
with the remaining percentage of humpbacks coming from the Mexico DPS.
    While in their Alaskan feeding grounds, humpback whales prey on a 
variety of euphausiids and small schooling fishes including herring, 
smelt, capelin, sandlance, juvenile

[[Page 52398]]

pollock, and salmon smolts (Kawamura 1980, Krieger and Wing 1986, 
Witteveen et al. 2008, Straley et al. 2017, Chenoweth et al. 2017). 
Herring targeted by Southeast Alaska whales in Lynn Canal during 2007-
2009 winters were lipid-rich, with energy content ranging from 7.3-10.0 
kJ/gram (Vollenweider et al. 2011). The local distribution of humpbacks 
in Southeast Alaska appears to be correlated with the density and 
seasonal availability of prey, particularly herring and euphausiids 
(Moran et al. 2017). Important feeding areas include Glacier Bay and 
adjacent portions of Icy Strait, Stephens Passage/Frederick Sound, 
Seymour Canal, Lynn Canal, and Sitka Sound and these areas have been 
included in the designation of a Biologically Important Area for 
humpbacks in the Gulf of Alaska. During autumn and winter, the non-
breeding season, humpbacks remaining in Southeast Alaska target areas 
where herring and eulachon are abundant, such as Seymour Canal, Berners 
Bay, Auke Bay, Lynn Canal, and Stephens Passage (Krieger and Wing 1986, 
Moran et al. 2017). Over 2,940 and 2,019 humpback whale foraging-days 
were documented in Lynn Canal alone in 2007-2008 and 2008-2009 winter 
seasons, respectively (Moran et al. 2017).
    Fidelity to feeding grounds by individual humpbacks is well 
documented; interchange between Alaskan feeding grounds is rare 
(Witteveen and Wynne 2017). Long-term research and photo-identification 
efforts have documented individual humpbacks that have returned to the 
same feeding grounds for as many 45 years (Straley 2017, Witteveen and 
Wynne 2017, Gabriele et al. 2017). Based on fluke pattern 
identification, Krieger, Baker and Wing identified 189 unique whales in 
the Juneau to Glacier Bay and Seymour Canal area (Krieger et al. 1986). 
In recent years, 179 individual humpback whales were identified from 
the Juneau area, based upon fluke photographs taken between 2006 and 
2014 (Teerlink 2017). Humpback whales occur in the project area 
intermittently year-round. Auke Bay and Statter Harbor are thought to 
have certain habitat features that attract humpback whales in recent 
years. The aggregation of herring in inner Auke Bay provide a habitat 
where whales may make energetic decisions to exploit small volumes of 
fish and rest to conserve energy between foraging opportunities.
    Humpback whales utilize habitats in the project area 
intermittently. The breakwater and other dock structures appear to 
serve as fish-attracting devices, where forage fish (herring, capelin, 
sandlance, pollock, and juvenile salmon) aggregate and are targeted by 
diving humpback whales. Two humpback whales in recent years have also 
targeted a shallow trough off the east end of the Statter Harbor 
breakwater for deeper diving foraging excursions targeting herring and 
possibly juvenile pollock (Ridgway pers. observ.). Some individual 
whales enter Auke Bay through the north Coghlan Island entrance and 
conduct a pattern of exploitation or ``browsing'' in the bay and inner 
harbor. In this area some whales lunge feed and gulp massive volumes of 
feed in seawater immediately adjacent to or rubbing against boats, 
docks and other structures in deep to shallow waters throughout the 
action area. These whales have been observed continuing a pattern 
search alongshore to Auke Creek and up Fritz Cove, where they have been 
seen lunge feeding in small coves and gullies in shallow water to 
aggregate schooling fish.
    Because humpback whale individuals of different DPS origin are 
indistinguishable from one another in Alaska (unless fluke patterns are 
linked to the individual in both feeding and breeding ground), the 
frequency of occurrence of animals by DPS is only estimated using the 
DPS ratio, based upon the assumption that the ratio is consistent 
throughout the Southeast Alaska region (Wade et al. 2016).

Harbor seals

    The Lynn Canal/Stephens Passage stock is found in the project area 
waters. The current population estimate for the Lynn Canal/Stephens 
Passage stock is 9,478 individuals, and the 5-year trend estimate is -
176. The probability of decrease of this stock is 0.71, indicating that 
evidence suggests that the stock is declining, however 9 of the 12 
Alaska harbor seal stocks are showing a trend of increasing populations 
(Muto et al. 2018). Typically harbor seals will stay within 16 miles 
(25 km) of shore, but they have been found up to 62 miles (100 km) from 
the shore (Klinkhart et al. 2008). Harbor seal movement is highly 
variable, with no seasonal patterns identified.
    Harbor seals use a variety of terrestrial sites to haul out for 
resting (year-round), pupping (May-July), and molting (August-
September) including tidal and intertidal reefs, beaches, sand bars, 
and glacial/sea ice (Sease 1992; Klinkhart et al. 2008). Some sites 
have traditional/historic value for pupping and molting while others 
are used as temporary resting sites during seasonal foraging trips.
    Harbor seals are residents of the project area and observed within 
the harbor on a regular basis and can be found within the immediate 
project vicinity on a daily basis. Over the last three winters, a group 
of up to 12 harbor seals has been observed in inner Statter Harbor near 
the harbormaster building along with 1-2 dispersed seals near the Auke 
Creek shoreline (Kate Wynne pers. observ.). Additionally, other counts 
from 2014-2016 recorded 2-16 animals within Statter Harbor. Up to 52 
individual seals have been photographed simultaneously hauled out on 
the nearby dock at Fishermen's Bend, located in the northwest corner of 
Statter harbor (Ridgway unpubl. Data). It is assumed that the majority 
of animals that haul out on the nearby floats at Fishermen's Bend are 
likely to go under water and resurface throughout the duration of the 
project. However, further clarification on the number of individual 
seals likely to occur in the project area is difficult as harbor seals 
are not easily identifiable at an individual level.

Steller Sea Lions

    The Steller sea lion was listed as a threatened species under the 
ESA in 1990 following declines of 63 percent on certain rookeries since 
1985 and declines of 82 percent since 1960 (55 FR 12645). In 1997, two 
DPSs of Steller sea lion were identified based on differences in 
genetics, distribution, phenotypic traits, and population trends: the 
Western DPS and Eastern DPS (Fritz et al. 2013).
    The Eastern DPS (eDPS) is commonly found in the project area waters 
and were most recently surveyed in Southeast Alaska in June-July of 
2015. The current population estimate for the eDPS is 71,562 
individuals of which 52,139 are non-pups and 19,423 are pups. In 
Southeast Alaska the estimated total abundance is 28,594 individuals of 
which 20,756 are non-pups and 7,838 are pups. The eDPS has been 
increasing between 1990 to 2015 with an estimated annual increase of 
4.76 percent for pups and 2.84 percent for non-pups. (Muto et al. 2018) 
The Western DPS (wDPS) is found infrequently in the project area 
waters, but have been sighted previously. The current abundance 
estimate for the U.S. portion of the wDPS is 50,983 of which 12,492 
were pups and 38,491 were non-pups. This is the minimum estimate for 
only the U.S. portion of the wDPS. It is the minimum count because the 
counts were not corrected for animals at sea during the survey. The 
overall trend for the wDPS in Alaska is an annual increase of 1.94

[[Page 52399]]

percent for non-pups and 1.87 percent for pups. (Muto et al. 2018)
    There is no critical habitat designated for Steller sea lions 
within the action area. The action area is located approximately 12 
nautical miles (22.22 kilometers) from around Benjamin Island, well 
outside of the 3,000-ft (914.4-m) designated critical habitat boundary 
designation.
    Steller sea lions occur in Auke Bay in winter on an intermittent 
basis, but their genetic and stock-designation identities are rarely 
known: individuals are indistinguishable unless sea lions are branded 
(and the brand is observed). Satellite-tagged individual animals from 
the Benjamin Island haulout and Auke Bay were observed multiple times 
between November 2010 and January 2011 (Fadely 2011), and the Auke Bay 
boating community frequently observes Steller sea lions moving to and 
from the haulout complex into Auke Bay.
    From 2013-2017, Steller sea lions have been documented in Auke Bay 
travelling as individuals or in herds of 50 to an estimated 120+ 
animals, during every month of the winter season. During winter 2015-
2016, Steller sea lions foraged aggressively on young herring and 1-2-
year-old Walleye pollock for over 20 days, continuously. Some sea lions 
were also observed consuming small flatfish, likely yellowfin sole, 
harvested from the seafloor (depth 25-45 m), during this period. While 
no sea lions were observed hauled out on beaches or structures in the 
harbor, large rafts of 20-50 animals formed and rested in the outer 
harbor area between foraging bouts. Simultaneous surface counts of 121 
individual sea lions suggests that likely upwards of 200 animals or 
more were targeting prey in Statter Harbor during herring aggregation 
events. These 121 to 200 animals comprise roughly 20 to 30 percent of 
the animals typically found at the Benjamin Island and Little Island 
haulout complexes during winter months. (Ridgway pers. observ.)
    Only three individual, branded wDPS Steller sea lions have been 
observed at Benjamin Island, the closest haulout, from 2003-2006 with a 
maximum of 3 sightings per individual. No branded wDPS individuals have 
been observed in the ADF&G surveys from 2007-2016. The 2007 ADF&G 
surveys offer the most abundant data for Steller sea lion counts at 
Benjamin Island. A total of 11 surveys were conducted between January 
and July 2017, ranging from 0-768 Steller sea lions, with an average 
count of 404 individuals. In 2007 no wDPS animals were observed. While 
it is possible an individual from the wDPS may be at the Benjamin 
Island haulout, it is rare, and none have been documented at this 
haulout for the last decade (Jemison pers. comm. 2017).
    Although recent data in the northern part of the eastern DPS 
indicate movement of western sea lions east of the 144[deg] line, the 
mixed part of the range remains small (Jemison et al. 2013). Based on 
observations by ADF&G over the last decade this project is unlikely to 
impact wDPS individuals. A recent IHA application for the Haines Ferry 
Terminal indicated that using branded animal ratios, a conservative 
estimate of 1.6 percent eDPS individuals may occur at the Gran Point 
haulout based on personal communication the applicant had with the 
Alaska Regional Office (shown in Figure 5 in the application). To be 
conservative it is assumed that 2 percent of the Steller sea lions at 
in this project area may be from the wDPS.

Harbor Porpoise

    In Alaska, harbor porpoises are currently divided into three 
stocks, based primarily on geography: (1) The Southeast Alaska stock--
occurring from the northern border of British Columbia to Cape 
Suckling, Alaska, (2) the Gulf of Alaska stock--occurring from Cape 
Suckling to Unimak Pass, and (3) the Bering Sea stock--occurring 
throughout the Aleutian Islands and all waters north of Unimak Pass. 
Only the Southeast Alaska stock is considered in this proposed IHA 
because the other stocks are not found in the geographic area under 
consideration.
    There are no subsistence uses of this species; however, as noted 
above, entanglement in fishing gear contributes to human-caused 
mortality and serious injury. Muto et al. (2018) also reports harbor 
porpoise are vulnerable to physical modifications of nearshore habitats 
resulting from urban and industrial development (including waste 
management and nonpoint source runoff) and activities such as 
construction of docks and other over-water structures, filling of 
shallow areas, dredging, and noise (Linnenschmidt et al., 2013).
    Information on harbor porpoise abundance and distribution in Auke 
Bay has not been systematically collected. While sightings of harbor 
porpoise in Statter Harbor are rare, they are an inconspicuous species, 
often traveling alone or in pairs, difficult for marine mammal 
observers to sight, making any approach to a monitoring zone 
potentially difficult to detect. The applicant did not request 
authorization of take of harbor porpoise because they are not known to 
regularly occur in the vicinity of the project site. However, because 
the species has been rarely observed in the area and due to the 
difficulty of implementing mitigation sufficient to avoid incidental 
take of animals that do occur in the area, we have determined it 
appropriate to propose authorization of take of harbor porpoise

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 
decibels (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. The functional groups and 
the associated frequencies are indicated below (note that these 
frequency ranges correspond to the range for the composite group, with 
the entire range not necessarily reflecting the capabilities of every 
species within that group):
     Low-frequency cetaceans (mysticetes): generalized hearing 
is estimated to occur between approximately 7 hertz (Hz) and 35 
kilohertz (kHz);
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): generalized hearing is estimated to occur 
between approximately 150 Hz and 160 kHz;
     High-frequency cetaceans (porpoises, river dolphins, and 
members of the genera Kogia and Cephalorhynchus; including two members 
of the genus Lagenorhynchus,

[[Page 52400]]

on the basis of recent echolocation data and genetic data): generalized 
hearing is estimated to occur between approximately 275 Hz and 160 kHz.
     Pinnipeds in water; Phocidae (true seals): generalized 
hearing is estimated to occur between approximately 50 Hz to 86 kHz;
     Pinnipeds in water; Otariidae (eared seals): generalized 
hearing is estimated to occur between 60 Hz and 39 kHz.
    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. 
Four marine mammal species (two cetacean and two pinniped (one otariid 
and one phocid) species) have the reasonable potential to co-occur with 
the proposed survey activities. Please refer to Table 1. Of the 
cetacean species that may be present, humpback whales are classified as 
low-frequency cetaceans, and harbor porpoise are classified as high-
frequency cetaceans.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

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

Description of Sound

    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in Hz or cycles per second. Wavelength is the distance 
between two peaks of a sound wave; lower frequency sounds have longer 
wavelengths than higher frequency sounds. Amplitude is the height of 
the sound pressure wave or the `loudness' of a sound and is typically 
measured using the dB scale. A dB is the ratio between a measured 
pressure (with sound) and a reference pressure (sound at a constant 
pressure, established by scientific standards). It is a logarithmic 
unit that accounts for large variations in amplitude; therefore, 
relatively small changes in dB ratings correspond to large changes in 
sound pressure. When referring to SPLs(the sound force per unit area), 
sound is referenced in the context of underwater sound pressure to one 
microPascal ([mu]Pa). One pascal is the pressure resulting from a force 
of one newton exerted over an area of one square meter. The source 
level (SL) represents the sound level at a distance of 1 m from the 
source (referenced to 1 [mu]Pa). The received level is the sound level 
at the listener's position. Note that all underwater sound levels in 
this document are referenced to a pressure of 1 [micro]Pa and all 
airborne sound levels in this document are referenced to a pressure of 
20 [micro]Pa.
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. Rms is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick 1983). Rms accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. The 
compressions and decompressions associated with sound waves are 
detected as changes in pressure by aquatic life and man-made sound 
receptors such as hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound. Ambient 
sound is defined as environmental background sound levels lacking a 
single source or point (Richardson et al., 1995), and the sound level 
of a region is defined by the total acoustical energy being generated 
by known and unknown sources. These sources may include physical (e.g., 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
sound (e.g., vessels, dredging, aircraft, construction). A number of 
sources contribute to ambient sound, including the following 
(Richardson et al., 1995):
     Wind and waves: The complex interactions between wind and 
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of 
naturally occurring ambient noise for frequencies between 200 Hz and 50 
kilohertz (kHz) (Mitson 1995). In general, ambient sound levels tend to 
increase with increasing wind speed and wave height. Surf noise becomes 
important near shore, with measurements collected at a distance of 8.5 
km from shore showing an increase of 10 dB in the 100 to 700 Hz band 
during heavy surf conditions;
     Precipitation: Sound from rain and hail impacting the 
water surface can become an important component of total noise at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times;
     Biological: Marine mammals can contribute significantly to 
ambient noise levels, as can some fish and shrimp. The frequency band 
for biological contributions is from approximately 12 Hz to over 100 
kHz; and
     Anthropogenic: Sources of ambient noise related to human 
activity include transportation (surface vessels and aircraft), 
dredging and construction, oil and gas drilling and production, seismic 
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise 
typically dominates the total ambient noise for frequencies between 20 
and 300 Hz. In general, the frequencies of anthropogenic sounds are 
below 1 kHz and, if higher frequency sound levels are created, they 
attenuate rapidly (Richardson et al., 1995). Sound from identifiable 
anthropogenic sources other than the activity of interest (e.g., a 
passing vessel) is sometimes termed background sound, as opposed to 
ambient sound.
    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

[[Page 52401]]

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.
Description of Sounds Sources
    In-water construction activities associated with the project would 
include vibratory pile removal, dredging, and blasting. Sound sources 
can be divided into broad categories based on various criteria or for 
various purposes. With regard to temporal properties, sounds are 
generally considered to be either continuous or transient (i.e., 
intermittent). Continuous sounds are simply those whose sound pressure 
level remains above ambient sound during the observation period (ANSI, 
2005). Intermittent sounds are defined as sounds with interrupted 
levels of low or no sound (NIOSH, 1998). Sound sources may also be 
categorized based on their potential to damage hearing. The sounds 
produced by these activities fall into one of two general sound types: 
Impulsive and non-impulsive (defined in the following). 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). Please see Southall 
et al. (2007) for an in-depth discussion of these concepts.
    Impulsive sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) are by definition intermittent, and produce 
signals that are brief (typically considered to be less than one 
second), broadband, atonal transients (ANSI 1986; Harris 1998; NIOSH 
1998; ISO 2003; ANSI 2005) and occur either as isolated events or 
repeated in some succession. Impulsive sounds are all characterized by 
a relatively rapid rise from ambient pressure to a maximal pressure 
value followed by a rapid decay period that may include a period of 
diminishing, oscillating maximal and minimal pressures, and generally 
have an increased capacity to induce physical injury as compared with 
sounds that lack these features.
    Non-impulsive sounds can be tonal, narrowband, or broadband, brief 
or prolonged, and may be either continuous or intermittent (ANSI 1995; 
NIOSH 1998). Some of these non-impulsive sounds can be transient 
signals of short duration but without the essential properties of 
impulses (e.g., rapid rise time). Examples of non-impulsive sounds 
include those produced by vessels, aircraft, machinery operations such 
as drilling or dredging, vibratory pile driving, and active sonar 
systems. The duration of such sounds, as received at a distance, can be 
greatly extended in a highly reverberant environment.
    The use of explosives for two days of blasting, is considered an 
impulsive sound, which is characterized by a short duration, abrupt 
onset, and rapid decay. Exposure to high intensity sound may result in 
behavioral reactions and auditory effects such as a noise-induced 
threshold shift--an increase in the auditory threshold after exposure 
to noise (Finneran et al., 2005). The proposed project also includes 
the use of various low-level non-impulsive acoustic sources including 
dredging, that would consistently emit noise for an extended period of 
time (up to 45 days) and increase vessel traffic in the vicinity of a 
small harbor. The source levels as well as impacts from dredging and 
fill placement activities are sources with generally lower source 
levels than many other sources we consider and are not thought to be 
dissimilar to ambient noise levels in an area with sustained 
anthropogenic activity and vessel traffic, such as Statter Harbor, and 
may range from having the potential to cause Level B harassment to 
exposure to noise that does not result in harassment. Here, we make 
conservative assessments of the potential to harass marine mammals 
incidental to the project and, in the Estimated Take section, 
accordingly propose to authorize take, by Level B harassment only for 
some of these lesser known sources.

Acoustic Impacts

    Anthropogenic sounds cover a broad range of frequencies and sound 
levels and can have a range of highly variable impacts on marine life, 
from none or minor to potentially severe responses, depending on 
received levels, duration of exposure, behavioral context, and various 
other factors. The potential effects of underwater sound from active 
acoustic sources can potentially result in one or more of the 
following; temporary or permanent hearing impairment, non-auditory 
physical or physiological effects, behavioral disturbance, stress, and 
masking (Richardson et al., 1995; Gordon et al., 2004; Nowacek et al., 
2007; Southall et al., 2007; Gotz et al., 2009). The degree of effect 
is intrinsically related to the signal characteristics, received level, 
distance from the source, and duration of the sound exposure. In 
general, sudden, high level sounds can cause hearing loss, as can 
longer exposures to lower level sounds. Temporary or permanent loss of 
hearing will occur almost exclusively for noise within an animal's 
hearing range. We first describe specific manifestations of acoustic 
effects before providing discussion specific to the City of Juneau's 
construction activities.
    Richardson et al. (1995) described zones of increasing intensity of 
effect that might be expected to occur, in relation to distance from a 
source and assuming that the signal is within an animal's hearing 
range. First is the area within which the acoustic signal would be 
audible (potentially perceived) to the animal, but not strong enough to 
elicit any overt behavioral or physiological response. The next zone 
corresponds with the area where the signal is audible to the animal and 
of sufficient intensity to elicit behavioral or physiological 
responsiveness. Third is a zone within which, for signals of high 
intensity, the received level is sufficient to potentially cause 
discomfort or tissue damage to auditory or other systems. Overlaying 
these zones to a certain extent is the area within which masking (i.e., 
when a sound interferes with or masks the ability of an animal to 
detect a signal of interest that is above the absolute hearing 
threshold) may occur; the masking zone may be highly variable in size.
    We describe the more severe effects (i.e., permanent hearing 
impairment, certain non-auditory physical or physiological effects) 
only briefly as we do not expect that there is a reasonable likelihood 
that the City of Juneau's activities may result in such effects (see 
below for further discussion). Marine mammals exposed to high-intensity 
sound, or to lower-intensity sound for prolonged periods, can 
experience hearing threshold shift (TS), which is the loss of hearing 
sensitivity at certain frequency ranges (Kastak et al., 1999; Schlundt 
et al., 2000; Finneran et al., 2002, 2005b). TS can be permanent (PTS), 
in which case the loss of hearing sensitivity is not fully recoverable, 
or temporary (TTS), in which case the animal's hearing threshold would 
recover over time (Southall et al., 2007). Repeated sound exposure that 
leads to TTS could cause PTS. In severe cases of PTS, there can be 
total or partial deafness, while in most cases the animal

[[Page 52402]]

has an impaired ability to hear sounds in specific frequency ranges 
(Kryter 1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several dB above that which induces mild TTS: a 40-dB 
threshold shift approximates PTS onset; e.g., Kryter et al., 1966; 
Miller, 1974), whereas a 6-dB threshold shift approximates TTS onset 
(e.g., Southall et al., 2007). Based on data from terrestrial mammals, 
a precautionary assumption is that the PTS thresholds for impulse 
sounds (such as bombs) are at least 6 dB higher than the TTS threshold 
on a peak-pressure basis and PTS cumulative sound exposure level 
thresholds are 15 to 20 dB higher than TTS cumulative sound exposure 
level thresholds (Southall et al., 2007). Given the higher level of 
sound or longer exposure duration necessary to cause PTS as compared 
with TTS, it is considerably less likely that PTS could occur.
    TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter 1985). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. Few data 
on sound levels and durations necessary to elicit mild TTS have been 
obtained for marine mammals.
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. 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. 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 occurs during a time 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 a time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts.
    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 three species of pinnipeds (northern elephant seal 
(Mirounga angustirostris), harbor seal, and California sea lion 
(Zalophus californianus)) exposed to a limited number of sound sources 
(i.e., mostly tones and octave-band noise) in laboratory settings 
(e.g., Finneran et al., 2002; Nachtigall et al., 2004; Kastak et al., 
2005; Lucke et al., 2009; Popov et al., 2011). In general, harbor seals 
(Kastak et al., 2005; Kastelein et al., 2012a) and harbor porpoises 
(Lucke et al., 2009; Kastelein et al., 2012b) have a lower TTS onset 
than other measured pinniped or cetacean species. Additionally, the 
existing marine mammal TTS data come from a limited number of 
individuals within these species. There are no data 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 Finneran (2015).

Physiological Effects

    In addition to PTS and TTS, there is a potential for non-auditory 
physiological effects or injuries that theoretically might occur in 
marine mammals exposed to high level underwater sound or as a secondary 
effect of extreme behavioral reactions (e.g., change in dive profile as 
a result of an avoidance reaction) caused by exposure to sound. These 
impacts can include neurological effects, bubble formation, resonance 
effects, and other types of organ or tissue damage (Cox et al., 2006; 
Southall et al., 2007; Zimmer and Tyack 2007). The City of Juneau's 
activities involve the use of devices such as explosives, which has 
been associated with these types of effects. The underwater explosion 
will send a shock wave and blast noise through the water, release 
gaseous by-products, create an oscillating bubble, and cause a plume of 
water to shoot up from the water surface. The shock wave and blast 
noise are of most concern to marine animals. The effects of an 
underwater explosion on a marine mammal depends on many factors, 
including the size, type, and depth of both the animal and the 
explosive charge; the depth of the water column; and the standoff 
distance between the charge and the animal, as well as the sound 
propagation properties of the environment. Potential impacts can range 
from brief effects (such as behavioral disturbance), tactile 
perception, physical discomfort, slight injury of the internal organs 
and the auditory system, to death of the animal (Yelverton et al., 
1973; DoN, 2001). Non-lethal injury includes slight injury to internal 
organs and the auditory system; however, delayed lethality can be a 
result of individual or cumulative sublethal injuries (DoN, 2001). 
Immediate lethal injury would be a result of massive combined trauma to 
internal organs as a direct result of proximity to the point of 
detonation (DoN 2001). Generally, the higher the level of impulse and 
pressure level exposure, the more severe the impact to an individual.
    Injuries resulting from a shock wave take place at boundaries 
between tissues of different density. Different velocities are imparted 
to tissues of different densities, and this can lead to their physical 
disruption. Blast effects are greatest at the gas-liquid interface 
(Landsberg 2000). Gas-containing organs, particularly the lungs and 
gastrointestinal (GI) tract, are especially susceptible (Goertner 1982; 
Hill 1978; Yelverton et al., 1973). In addition, gas-containing organs 
including the nasal sacs, larynx, pharynx, trachea, and lungs may be 
damaged by compression/expansion caused by the oscillations of the 
blast gas bubble. Intestinal walls can bruise or rupture, with 
subsequent hemorrhage and escape of gut contents into the body cavity. 
Less severe GI tract injuries include contusions, petechiae (small red 
or purple spots caused by bleeding in the skin), and slight 
hemorrhaging (Yelverton et al., 1973).
    Because the ears are the most sensitive to pressure, they are the 
organs most sensitive to injury (Ketten 2000). Sound-related damage 
associated with blast noise can be theoretically distinct from injury 
from the shock wave, particularly farther from the explosion. If an 
animal is able to hear a noise, at some level it can damage its hearing 
by causing decreased sensitivity (Ketten 1995). Sound-related trauma 
can be lethal or sublethal. Lethal impacts are those that result in 
immediate death or serious debilitation in or near an intense source 
and are not, technically, pure acoustic trauma (Ketten 1995). Sublethal 
impacts include hearing loss, which is caused by exposures to 
perceptible

[[Page 52403]]

sounds. Severe damage (from the shock wave) to the ears includes 
tympanic membrane rupture, fracture of the ossicles, damage to the 
cochlea, hemorrhage, and cerebrospinal fluid leakage into the middle 
ear. Moderate injury implies partial hearing loss due to tympanic 
membrane rupture and blood in the middle ear. Permanent hearing loss 
also can occur when the hair cells are damaged by one very loud event, 
as well as by prolonged exposure to a loud noise or chronic exposure to 
noise. The level of impact from blasts depends on both an animal's 
location and, at outer zones, on its sensitivity to the residual noise 
(Ketten 1995).
    The above discussion concerning underwater explosions only pertains 
to open water detonations in a free field without mitigation. 
Therefore, given the low weight of the charges and small size of the 
detonation relative to large open water detonations in conjunction with 
monitoring and mitigation measures discussed below, The City of 
Juneau's two blasting events are not likely to have injury or mortality 
effects on marine mammals in the project vicinity. Instead, NMFS 
considers that The City of Juneau 's blasts are most likely to cause 
behavioral harassment and may cause TTS in a few individual marine 
mammals, as discussed below.

Behavioral Effects

    Behavioral disturbance may include a variety of effects, including 
subtle changes in behavior (e.g., minor or brief avoidance of an area 
or changes in vocalizations), more conspicuous changes in similar 
behavioral activities, and more sustained and/or potentially severe 
reactions, such as displacement from or abandonment of high-quality 
habitat. 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). Please see Appendices B-C of 
Southall et al. (2007) for a review of studies involving marine mammal 
behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure. As noted, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud, intermittent sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in 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). 
This highlights the importance of assessing the context of the acoustic 
effects alongside the received levels anticipated. Severity of effects 
from a response to an acoustic stimuli can likely vary based on the 
context in which the stimuli was received, particularly if it occurred 
during a biologically sensitive temporal or spatial point in the life 
history of the animal. There are broad categories of potential 
response, which we describe in greater detail here, that include 
alteration of dive behavior, alteration of foraging behavior, effects 
to breathing, interference with or alteration of vocalization, 
avoidance, and flight.
    Changes in dive behavior can vary widely, and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark 2000; Costa et al., 2003; Ng and Leung 2003; Nowacek et al., 
2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts

[[Page 52404]]

resulting from anthropogenic sound exposure (e.g., Kastelein et al., 
2001, 2005b, 2006; Gailey et al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
(Eubalaena glacialis) have been observed to shift the frequency content 
of their calls upward while reducing the rate of calling in areas of 
increased anthropogenic noise (Parks et al., 2007b). In some cases, 
animals may cease sound production during production of aversive 
signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path because of the presence of a sound or other stressors, 
and is one of the most obvious manifestations of disturbance in marine 
mammals (Richardson et al., 1995). For example, gray whales 
(Eschrictius robustus) are known to change direction--deflecting from 
customary migratory paths--in order to avoid noise from seismic surveys 
(Malme et al., 1984). Avoidance may be short-term, with animals 
returning to the area once the noise has ceased (e.g., Bowles et al., 
1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey 
et al., 2007). Longer-term displacement is possible, however, which may 
lead to changes in abundance or distribution patterns of the affected 
species in the affected region if habituation to the presence of the 
sound does not occur (e.g., Blackwell et al., 2004; Bejder et al., 
2006; Teilmann et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus 1996). The result of a flight response could range from brief, 
temporary exertion and displacement from the area where the signal 
provokes flight to, in extreme cases, marine mammal strandings (Evans 
and England 2001). However, it should be noted that response to a 
perceived predator does not necessarily invoke flight (Ford and Reeves 
2008), and whether individuals are solitary or in groups may influence 
the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil 1997; Fritz et al., 2002; Purser and Radford 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.

Stress Response

    An animal's perception of a threat may be sufficient to trigger 
stress responses consisting of some combination of behavioral 
responses, autonomic nervous system responses, neuroendocrine 
responses, or immune responses (e.g., Seyle 1950; Moberg 2000). In many 
cases, an animal's first and sometimes most economical (in terms of 
energetic costs) response is behavioral avoidance of the potential 
stressor. Autonomic nervous system responses to stress typically 
involve changes in heart rate, blood pressure, and gastrointestinal 
activity. These responses have a relatively short duration and may or 
may not have a significant long-term effect on an animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg 1987; Blecha 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker 2000; Romano 
et al., 2002b) and, more rarely, studied in wild populations (e.g., 
Romano et al., 2002a). For example, Rolland et al. (2012) found that 
noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and

[[Page 52405]]

other studies lead to a reasonable expectation that some marine mammals 
will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003).

Acoustic Effects, Underwater

    The effects of sounds from The City of Juneau's proposed activities 
might include one or more of the following: Temporary or permanent 
hearing impairment, non-auditory physical or physiological effects, 
behavioral disturbance, and masking (Richardson et al., 1995; Gordon et 
al., 2003; Nowacek et al., 2007; Southall et al., 2007). The effects of 
pile removal or dredging on marine mammals are dependent on several 
factors, including the type and depth of the animal; the pile size and 
type, and the intensity and duration of the pile removal or dredging 
sound; the substrate; the standoff distance between the pile and the 
animal; and the sound propagation properties of the environment. 
Impacts to marine mammals from pile removal and dredging activities are 
expected to result primarily from acoustic pathways. As such, the 
degree of effect is intrinsically related to the frequency, received 
level, and duration of the sound exposure, which are in turn influenced 
by the distance between the animal and the source. The further away 
from the source, the less intense the exposure should be. The substrate 
and depth of the habitat affect the sound propagation properties of the 
environment. The characteristics of dredging noise are such that there 
is a clear impulse peak, from the impact of the dredge making contact 
with the substrate, but then there is a prolonged period of sound which 
is the noise of the continual operation of the dredge delving the 
sediment. As such, we have chosen to consider the characteristics noise 
as a continuous source despite the impulse at the beginning of the 
waveform characterizing dredging noise. In addition, substrates that 
are soft (e.g., sand) would absorb or attenuate the sound more readily 
than hard substrates (e.g., rock), which may reflect the acoustic wave. 
Soft porous substrates would also likely require less time to extract 
the pile or dredge the substrate, and possibly less forceful equipment, 
which would ultimately decrease the intensity of the acoustic source.
    In the absence of mitigation, impacts to marine species could be 
expected to include physiological and behavioral responses to the 
acoustic signature (Viada et al., 2008). Potential effects from 
impulsive sound sources like blasting can range in severity from 
effects such as behavioral disturbance to temporary or permanent 
hearing impairment (Yelverton et al., 1973). Due to the nature of the 
sounds involved in the project, behavioral disturbance is the most 
likely effect from the proposed activity. Marine mammals exposed to 
high intensity sound repeatedly or for prolonged periods can experience 
hearing threshold shifts. PTS constitutes injury, but TTS does not 
(Southall et al., 2007). Due to the use mitigation measures discussed 
in detail in the Proposed Mitigation Section, it is unlikely but 
possible that PTS could occur from blasting.

Disturbance Reactions

    Responses to continuous sound, such as vibratory pile installation, 
have not been documented as well as responses to intermittent sounds. 
With pile removal as well as dredging activities, it is likely that the 
onset of sound sources could result in temporary, short-term changes in 
an animal's typical behavior and/or avoidance of the affected area. 
These behavioral changes may include (Richardson et al., 1995): 
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; and/or flight responses (e.g., 
pinnipeds flushing into water from haulouts or rookeries). Pinnipeds 
may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff 2006). If a marine mammal responds to a 
stimulus by changing its behavior (e.g., through relatively minor 
changes in locomotion direction/speed or vocalization behavior), the 
response may or may not constitute taking at the individual level, and 
is unlikely to affect the stock or the species as a whole. However, if 
a sound source displaces marine mammals from an important feeding or 
breeding area for a prolonged period, impacts on animals, and if so 
potentially on the stock or species, could potentially be significant 
(e.g., Lusseau and Bejder 2007; Weilgart 2007).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be biologically significant if the change affects 
growth, survival, or reproduction. Significant behavioral modifications 
that could potentially lead to effects on growth, survival, or 
reproduction include:
     Drastic changes in diving/surfacing patterns (such as 
those thought to cause beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Longer-term habitat abandonment due to loss of desirable 
acoustic environment; and
     Longer-term cessation of feeding or social interaction.
    The onset of behavioral disturbance from anthropogenic sound 
depends on both external factors (characteristics of sound sources and 
their paths) and the specific characteristics of the receiving animals 
(hearing, motivation, experience, demography) and is difficult to 
predict (Southall et al., 2007).

Auditory 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., 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.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
when disrupting or altering critical behaviors. It is important to 
distinguish TTS and PTS, which persist after the sound exposure, from 
masking, which occurs during the sound exposure. Because masking 
(without resulting in TS) is not associated with

[[Page 52406]]

abnormal physiological function, it is not considered a physiological 
effect, but rather a potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential impacts. For example, low-frequency 
signals may have less effect on high-frequency echolocation sounds 
produced by odontocetes but are more likely to affect detection of 
mysticete communication calls and other potentially important natural 
sounds such as those produced by surf and some prey species. The 
masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007b; Di Iorio and Clark 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore 2014). Masking can be tested 
directly in captive species (e.g., Erbe 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.

Anticipated Effects on Habitat

    The proposed activities at the project area would not result in 
permanent negative impacts to habitats used directly by marine mammals, 
but may have potential short-term impacts to food sources such as 
forage fish and may affect acoustic habitat. There are no known 
foraging hotspots or other ocean bottom structure of significant 
biological importance to marine mammals present in the marine waters of 
the project area during the construction window other than the 
occurrence of the foraging BIA for humpback whales. While humpbacks are 
known to feed in Statter Harbor, this is a small portion of the overall 
area designated as important. The small portion of the BIA affected by 
the construction noise, in conjunction with the short temporal scale of 
construction activity (57 days, only in daylight hours) make it 
unlikely the effects of the construction will significantly alter the 
foraging habitat of humpbacks in southeast Alaska. Therefore, the main 
impact issue associated with the proposed activity would be temporarily 
elevated sound levels and the associated direct effects on marine 
mammals, as discussed previously in this document. The primary 
potential acoustic impacts to marine mammal habitat are associated with 
elevated sound levels produced by pile removal, dredging, and blasting 
in the area. However, other potential impacts to the surrounding 
habitat from physical disturbance are also possible.

In-Water Construction Effects on Potential Prey (Fish)

    Construction activities would produce continuous (i.e., vibratory 
pile removal and dredging) and pulsed (blasting) 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 impulsive sounds such as 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 removal and dredging 
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. While impacts from blasting 
to fish are more severe, including barotrauma and mortality, the blast 
will last approximately one second on each of two days, making the 
duration of this impact short term. In general, impacts to marine 
mammal prey species are expected to be minor and temporary due to the 
short timeframe for the project.

Effects on Potential Foraging Habitat

    The area likely impacted by the project is relatively small 
compared to the available habitat in Auke Bay (e.g., most of the 
impacted area is limited near the northwest corner of the bay). 
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 construction activity 
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 
Auke Bay.
    The duration of the construction activities is relatively short. 
The construction window is for a maximum of 57 days and each day, 
construction activities would occur for less than half of the day. 
Impacts to habitat and prey are expected to be minimal based on the 
short duration of activities.
    In summary, given the short daily duration of sound associated with 
individual construction activities and the relatively small areas being 
affected, the proposed actions are not likely to have a permanent, 
adverse effect on any fish habitat, or populations of fish species. 
Thus, any impacts to marine mammal habitat are not expected to cause 
significant or long-term consequences for individual marine mammals or 
their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as: Any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).

[[Page 52407]]

    Authorized takes would primarily be by Level B harassment, as use 
of the explosives, vibratory pile removal, and dredging has the 
potential to result in disruption of behavioral patterns for individual 
marine mammals. There is also some potential for auditory injury and 
(Level A harassment) to result from blasting, primarily for high 
frequency species and phocids because predicted auditory injury zones 
are larger than for low-frequency species and otariids. The proposed 
mitigation and monitoring measures are expected to minimize the 
severity of such 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). Thresholds have also 
been developed to identify the pressure levels above which animals may 
incur different types of tissue damage from exposure to pressure waves 
from explosive detonation.
    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. This threshold is not applied to single 
detonations as the sound is instantaneous in nature such that a 
behavioral harassment is not expected to result, although TTS may 
occur. NMFS predicts that marine mammals are likely to be behaviorally 
harassed in a manner we consider Level B harassment when exposed to 
underwater anthropogenic noise above received levels of 120 dB re 1 
[mu]Pa (rms) for continuous (e.g., vibratory pile-driving, drilling) 
and above 160 dB re 1 [mu]Pa (rms) for intermittent (e.g., impact pile 
driving) sources.
    The City of Juneau's proposed activity includes the use of 
continuous sounds (vibratory pile removal, dredging) and therefore the 
120 dB re 1 [mu]Pa (rms) threshold for behavioral harassment is 
applicable. While the proposed activity also includes impulsive sounds 
(blasting), the 160 dB re 1 1 [mu]Pa (rms) threshold for behavioral 
harassment is not applicable, as behavioral harassment is not expected 
from single detonation events, although TTS is possible.
    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). The City of Juneau's proposed activity 
includes the use non-impulsive (dredging, vibratory pile removal) 
sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at: 
https://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

                     Table 2--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                             PTS onset acoustic thresholds *
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1[mu]Pa, and cumulative sound exposure (LE) has a
  reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to reflect American National
  Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
  frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
  being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
  designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
  that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
  exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
  is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

    Explosive sources--Based on the best available science, NMFS uses 
the acoustic and pressure thresholds indicated in Table 3 to predict 
the onset of behavioral harassment, PTS, tissue damage, and mortality.

[[Page 52408]]

[GRAPHIC] [TIFF OMITTED] TN17OC18.026

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.
    Vibratory removal--The closest known measurements of vibratory pile 
removal similar to this project are from the Kake Ferry Terminal 
project for vibratory extraction of an 18-in steel pile. The extraction 
of 18-in steel pipe pile using a vibratory hammer resulted in 
underwater noise levels reaching 156.2 dB RMS at 7 m (Denes et al. 
2016). The pile diameters for the proposed project are smaller, thus 
the use of noise levels associated with the pile extraction at Kake may 
be somewhat conservative. For timber pile removal, the Seattle Pier 62/
63 sound source verification report contains an appendix with source 
measurements at different distances for 63 individual pile removals 
(WSDOT, 2015). When the data are normalized to 10 m, the median source 
level is 152 dB RMS at 10 m.
    Dredging--For dredging, sound source data was used from bucket 
dredging operations in Cook Inlet, Alaska (Dickerson et al. 2001). 
Dredging in that project consisted of six distinct events, including 
the bucket striking the channel bottom, bucket digging, winch in/out as 
the bucket is lowered/raised, dumping of the material on the barge and 
emptying the barge at the disposal site. Although the waveform of the 
bucket strike has a high peak sound pressure with rapid rise time and 
rapid decay (characteristics typical of an impulsive sound source), the 
duration of the source signal was longer than what is often considered 
for an impulsive sound source, about 50 seconds, which is the 
approximate duration of one continuous noise signal from the dredging 
equipment. The events following the initial waveform impulse were of 
longer duration and were non-impulsive in form and therefore dredging 
was analyzed as a continuous source. Dickerson et al (2001) took 104 
SPL RMS measurements for the first five distinct phases of the dredging 
cycle and averaged them, including the impulse in the waveform of the 
dredge making contact with the substrate. These averages were distance 
corrected to determine an average SPL of 150.5 dB RMS at 1 m for the 
bucket dredging process, with an assumed maximum duration of up to 50 
seconds, of non-impulsive, continuous noise.
    Blasting--Historic data from an analog project were analyzed to 
create a conservative attenuation model for anticipated pressure levels 
from confined blasting in drilled shafts in underwater bedrock. Sound 
pressure data from the analog project was analyzed to compare source 
pressure levels to received impulse levels (Alaska Seismic, 2018). 
These models were used to predict distances to the peak level and 
impulse thresholds summarized above in Table 3. Cumulative source 
levels from the analog project were used in conjunction with the NMFS 
2018 updated User Spreadsheet Tool for predicting threshold shift 
isopleths for multiple detonations, after being corrected to a 1-m 
reference source level. The median of 10 measurements, consisting of 
detonations ranging from 19 to 78 individual holes for the detonation, 
resulted in a source level of 227.98 dB single shot SEL.
    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, NMFS 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, the NMFS User Spreadsheet predicts the closest distance at 
which, if

[[Page 52409]]

a marine mammal remained at that distance the whole duration of the 
activity, it would not incur PTS. Inputs used in the User Spreadsheet, 
and the resulting isopleths are reported below.

                                      Table 4--NMFS User Spreadsheet Inputs
----------------------------------------------------------------------------------------------------------------
                                               Timber removal   Steel removal       Dredging         Blasting
                                             -------------------------------------------------------------------
                                                                                                       E.2:
                                                                                                   Explosives:
            Spreadsheet tab used               A.1: Vibratory   A.1: Vibratory   A: Stationary:     impulsive,
                                                pile driving     pile driving    non-impulsive,    intermittent
                                                                                   continuous       (multiple
                                                                                                   detonations)
----------------------------------------------------------------------------------------------------------------
Source Level (Single Strike/shot SEL).......  ...............  ...............  ...............          227.975
Source Level (RMS SPL)......................              152            156.2            150.5  ...............
Weighting Factor Adjustment (kHz)...........              2.5              2.5                2                1
(a) Number of strikes/detonations in 1 h....  ...............  ...............  ...............                1
(a) Activity Duration (h) within 24-h period  ...............  ...............               11                1
Propagation (xLogR).........................               15               15               15               20
Distance of source level measurement (m) \+\               10                7                1  ...............
# of piles/shots in a 24 h period...........               16                4  ...............                1
Duration to drive (remove) a single pile                   20               20  ...............  ...............
 (min)......................................
----------------------------------------------------------------------------------------------------------------

    When using the inputs from Table 4, the outputs generated are 
summarized below in Table 5.

                                Table 5--NMFS User Spreadsheet Generated Outputs
                                            [User Spreadsheet Output]
----------------------------------------------------------------------------------------------------------------
                                                                     PTS Isopleth (meters)
                                             -------------------------------------------------------------------
                 Source type                    Low-frequency    High-frequency       Phocid          Otariid
                                                  cetaceans         cetaceans        pinnipeds       pinnipeds
----------------------------------------------------------------------------------------------------------------
Timber removal..............................               5.2               7.7             3.2             0.2
Steel Removal...............................               2.8               4.1             1.7             0.1
Dredging....................................               0.7               0.6             0.4             0.0
Blasting (SELcum) *.........................               176              59.1            71.4            10.1
Blasting (PK) *.............................              22.1             156.5            24.8             4.9
----------------------------------------------------------------------------------------------------------------
                                              TTS Isopleth (meters)
----------------------------------------------------------------------------------------------------------------
Blasting (SEL cum) *........................             989.8             332.3           401.7            56.9
Blasting (PK) *.............................              44.1             312.2            49.5             9.9
----------------------------------------------------------------------------------------------------------------
                                 Level B Behavioral Harassment Isopleth (meters)
----------------------------------------------------------------------------------------------------------------
Timber removal..............................                                1359.36
Steel removal...............................                                1813.14
Dredging....................................                                107.98
----------------------------------------------------------------------------------------------------------------
* Impulsive sounds have a dual metric threshold (SELcum and PK). Metric producing the largest isopleth should be
  used.

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations. Reliable densities are not available for Statter Harbor 
or the Auke Bay area. Generalized densities for the North Pacific would 
not be applicable given the high variability in occurrence and density 
at specific inlets and harbors. Therefore, the applicant consulted 
opportunistic sightings data from oceanographic surveys in Auke Bay and 
sightings from Auke Bay Marine Station observation pier for this 
specific harbor to arrive at a number of animals expected to occur 
within the harbor per day. For humpback whales, it is assumed that a 
maximum of two animals per day are likely to be seen in the harbor. For 
Steller sea lions, the potential maximum daily occurrence of animals is 
121 individuals within the harbor. For harbor seals, the maximum daily 
occurrence of animals is 52 individuals.

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate.
    Because reliable densities are not available, the applicant 
requests take based on the above mentioned maximum number of animals 
that may occur in the harbor per day multiplied by the number of days 
of the activity. The applicant varied these calculations based on 
certain factors.
    Humpback whale--Based on the size of the harassment zone for 
dredging, in combination with the Proposed Mitigation outlined below, 
the applicant does not expect humpback whales to approach the dredging 
vessel and therefore is not requesting take of humpback whales from 
dredging.

[[Page 52410]]

Because of the nature of blasting, there is no behavioral threshold 
associated with the activity, but TTS, which is a form of Level B 
harassment take, may occur. With a maximum take of two animals per day, 
multiplied by a maximum of 10 days of pile removal and two days of 
blasting (TTS), the applicant requests authorization of 24 Level B 
harassment takes of humpback whale.
    Steller sea lion--It is estimated that a maximum of 121 Steller sea 
lions may be seen in Statter Harbor within one day. A maximum take of 
121 animals per day for 10 days of pile removal is 1,210 Steller sea 
lions. Given the size of the Level B zone for dredging (108 m), it is 
possible Steller sea lions may approach the source vessel. However, 
given the small size of the zone, the applicant reduced the number of 
animals expected to be taken daily from dredging by 50 percent, to 60 
Steller sea lions daily. A maximum of 60 takes per day for 45 days of 
dredging is 2,700 takes of Steller sea lion. For blasting, which is 
confined to the inner harbor, the TTS zone (57 m) is even smaller than 
the size of the dredging zone. Therefore, if the same maximum of 60 
Stellers is assumed to be within the zone for two days of blasting, the 
result is a potential take of 120 Steller sea lions. No more than 20 of 
those Steller sea lions are assumed to be within range of the PTS 
blasting isopleths, with the remaining 100 takes potentially occurring 
in the TTS isopleth. While it is conservative to assume 20 Steller sea 
lions may occur within 10 meters of the blast source, they are 
regularly seen in the area and the explosives need to be detonated 
within a certain number of hours after being planted. It is possible 
that Stellers could approach the source and the detonation could no 
longer be delayed, exposing Steller sea lions to sound levels that may 
induce PTS. This adds to a total of 4,030 takes of Steller sea lion.
    Harbor seal--The largest known group size to occur in Statter 
Harbor is 52 individuals, which is the maximum number of takes per day 
used in the take estimation section for harbor seals. For 10 days of 
pile removal, using an assumed rate of 52 individuals per day, the 
potential take of harbor seals is 520. For 45 days of dredging, the 
estimated daily take was reduced by half due to the small size of the 
isopleth, resulting in an estimate of 1,170 takes. For blasting, it is 
assumed no more than 11 harbor seals would enter the inner harbor on a 
given day and therefore could occur within 71 meters of the blasting 
source. This results in a potential 22 Level A harassment takes of 
harbor seal due to blasting across two days. For the TTS blasting zone, 
which is 400 meters, 52 harbor seals could occur in the harbor area and 
were used to estimate a potential 104 TTS takes of harbor seal across 
two days of blasting. Summed together, this would result in 1,186 takes 
of harbor seal.
    Harbor porpoise--Very little is known about likelihood of 
occurrence of harbor porpoise in Statter Harbor but, as noted 
previously, they are rarely observed in the area and we assume that may 
occur, while their cryptic nature makes it difficult to mitigate all 
potential for take. If it is assumed one pair could be sighted per day 
for 10 days of pile removal, this would result in potential take of 20 
harbor porpoise. If the same methodology is applied, assuming a pair 
per two days on 45 days of dredging because of the infrequency of 
harbor porpoise and the size of the isopleth, this would result in take 
of 44 estimated harbor porpoise. For two days of blasting, it is 
assumed two harbor porpoise may occur each day in the TTS zone, for 
four total TTS takes, and one pair on each day may appear in the PTS 
zone, resulting in four Level A harassment takes of harbor porpoise.
    The total number of takes proposed are summarized in Table 6 below.

                                                        Table 6--Takes Proposed to be Authorized
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           Total level B   Total level A
                                                            Takes from      Takes from    TTS takes from  PTS takes from    harassment      harassment
                                                           pile removal      dredging        blasting        blasting          takes           takes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale..........................................              20               0               4               0              24               0
Steller sea lion........................................           1,210           2,700             100              20           4,010              20
Harbor seal.............................................             520           1,170             104              22           1,794              22
Harbor porpoise.........................................              20              44               4               4              68               4
--------------------------------------------------------------------------------------------------------------------------------------------------------

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 such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting such 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned) the likelihood of effective implementation (probability 
implemented as planned); and
    (2) the practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    In addition to the measures described later in this section, the 
City of Juneau will employ the following standard mitigation measures:
     Conduct a briefing between construction supervisors and 
crews and the marine mammal monitoring team prior to the start of 
construction, and when new personnel join the work, to explain 
responsibilities, communication

[[Page 52411]]

procedures, marine mammal monitoring protocol, and operational 
procedures;
     For in-water and over-water heavy machinery work, if a 
marine mammal comes within 10 m, operations must cease and vessels must 
reduce speed to the minimum level required to maintain steerage and 
safe working conditions. This 10 m shutdown encompasses the Level A 
harassment zone for pile removal and dredging and therefore this 
requirement is not listed separately.
     Work may only occur during daylight hours, when visual 
monitoring of marine mammals can be conducted;
     For those marine mammals for which Level B harassment take 
has not been requested, pile removal and dredging will shut down 
immediately when the animals are sighted approaching the monitoring 
zones;
     If take reaches the authorized limit for an authorized 
species, activity for which take is authorized will be stopped as these 
species approach the monitoring zones to avoid additional take of them.
    The following measures would apply to The City of Juneau's 
mitigation requirements:
    Establishment of Monitoring Zones for Level B-- The City of Juneau 
will establish Level B monitoring zones or zones of influence (ZOI) 
which are areas where SPLs are equal to or exceed the 120 dB rms 
threshold during vibratory removal and dredging. Similar harassment 
monitoring zones will be established for the TTS isopleths associated 
with each functional hearing group for blasting activities. Monitoring 
zones provide utility for observing by establishing monitoring 
protocols for areas adjacent to the shutdown zones. Monitoring zones 
enable observers to be aware of and communicate the presence of marine 
mammals in the project area outside the shutdown zone and thus prepare 
for a potential cease of activity should the animal enter the shutdown 
zone. The Level B monitoring zones are depicted in Table 7.

                                                         Table 7--Shutdown and Monitoring Zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           Monitoring zones                                            Shutdown zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                         High frequency           Low frequency
               Source                       cetacean                ceteacean                Phocid                Otariid              All species
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Removal--Steel...........  1,820 m...............  1,820 m...............  1,820 m..............  1,820 m..............  10 m
Vibratory Removal--Timber..........  1,360 m...............  1,360 m...............  1,360 m..............  1,360 m..............  10 m
Dredging...........................  110 m.................  110 m.................  110 m................  110 m................  10 m
Blasting (PTS).....................  160 m.................  180 m.................  80 m.................  10 m.................  10 m
Blasting (TTS).....................  340 m.................  990 m.................  410 m................  60 m.................  10 m
--------------------------------------------------------------------------------------------------------------------------------------------------------

As shown, the largest Level B zone is equal to 1,820 m, making it 
unlikely that PSOs would be able to view the entire harassment area. 
Due to this, Level B exposures will be recorded and extrapolated based 
upon the number of observed take and the percentage of the Level B 
harassment zone that was not visible.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
activity, or whenever a break in activity of 30 minutes or longer 
occurs, the observer will observe the shutdown and monitoring zones for 
a period of 30 minutes. The shutdown zone will be cleared when a marine 
mammal has not been observed within the zone for that 30-minute period. 
If a marine mammal is observed within the shutdown zone, activity 
cannot proceed until the animal has left the zone or has not been 
observed for 15 minutes. If the Level B harassment zone has been 
observed for 30 minutes and non-permitted species are not present 
within the zone, activity can commence and work can continue even if 
visibility becomes impaired within the Level B zone. When a marine 
mammal permitted for Level B take is present in the Level B harassment 
zone, activities may begin and Level B take will be recorded. As stated 
above, if the entire Level B zone is not visible at the start of 
construction, activity can begin. If work ceases for more than 30 
minutes, the pre-activity monitoring of both the Level B and shutdown 
zone will commence.
    For blasting, the TTS zone will be monitored for a minimum of 30 
minutes prior to detonating the blasts. If a marine mammal is sighted 
within the TTS zone, blasting will be delayed until the zone is clear 
of marine mammals for 30 minutes. This will continue as long as 
practicable within the constraints of the blasting design but not 
beyond sunset on the same day as the charges cannot lay dormant for 
more than 24 hours, which may force the detonation of the blast in the 
presence of marine mammals. Charges will be laid as early as possible 
in the morning.
    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.

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

[[Page 52412]]

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 construction activities. In addition, observers must 
record all incidents of marine mammal occurrence, regardless of 
distance from activity, and must document any behavioral reactions in 
concert with distance from construction activities.
    PSOs would be land-based observers. Observers will be stationed at 
locations that provide adequate visual coverage for shutdown and 
monitoring zones. Potential observation locations are depicted in 
Figures 2 and 3 of the applicant's Marine Mammal Mitigation and 
Monitoring Plan. A minimum of one observer would be placed at a vantage 
point providing total coverage of the monitoring zones and for 
observation zones larger than 500 m, at least one other additional 
observer will be placed at the outermost float or other similar vantage 
point in order to observe the extend observation zone. Optimal 
observation locations will be selected based on visibility and the type 
of work occurring. All PSOs would be trained in marine mammal 
identification and behaviors and are required to have no other project-
related tasks while conducting monitoring. In addition, monitoring 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. Monitoring of construction activities 
must be conducted by qualified PSOs (see below), who must have no other 
assigned tasks during monitoring periods. The applicant must adhere to 
the following conditions when selecting observers:
     Independent PSOs must be used (i.e., not construction 
personnel).
     At least one PSO must have prior experience working as a 
marine mammal observer during construction activities.
     Other PSOs may substitute education (degree in biological 
science or related field) or training for experience.
     Where a team of three or more PSOs are required, a lead 
observer or monitoring coordinator must be designated. The lead 
observer must have prior experience working as a marine mammal observer 
during construction.
     The applicant must submit PSO CVs for approval by NMFS.
    The applicant must ensure that observers have the following 
additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols.
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors.
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations.
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior.
     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.
    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of construction activities. It will 
include an overall description of work completed, a narrative regarding 
marine mammal sightings, and associated PSO data sheets. Specifically, 
the report must include:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Weather parameters (e.g., percent cover, visibility);
     Water conditions (e.g., sea state, tide state);
     Species, numbers, and, if possible, sex and age class of 
marine mammals;
     Description of any observable marine mammal behavior 
patterns, including bearing and direction of travel and distance from 
construction activity;
     Distance from construction activities to marine mammals 
and distance from the marine mammals to the observation point;
     Locations of all marine mammal observations; and
     Other human activity in the area.
    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 unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as a serious injury or mortality, The City of Juneau 
would immediately cease the specified activities and report the 
incident to the Office of Protected Resources, NMFS, and the Alaska 
Regional Stranding Coordinator. The report would include the following 
information:
     Description of the incident;
     Environmental conditions (e.g., Beaufort sea state, 
visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with The City of 
Juneau to determine what is necessary to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. The City of Juneau 
would not be able to resume their activities until notified by NMFS via 
letter, email, or telephone.
    In the event that The City of Juneau discovers an injured or dead 
marine mammal, and the lead PSO determines that the cause of the injury 
or death is unknown and the death is relatively recent (e.g., in less 
than a moderate state of decomposition as described in the next 
paragraph), the City of Juneau would immediately report the incident to 
the Office of Protected Resources, NMFS, and the Alaska Regional 
Stranding Coordinator. The report would include the same information 
identified in the paragraph above. Activities would be able to continue 
while NMFS reviews the circumstances of the incident. NMFS would work 
with the City of Juneau to determine whether modifications in the 
activities are appropriate.
    In the event that the City of Juneau discovers an injured or dead 
marine mammal and the lead PSO determines that the injury or death is 
not associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate

[[Page 52413]]

to advanced decomposition, or scavenger damage), the City of Juneau 
would report the incident to the Office of Protected Resources, NMFS, 
and the NMFS Alaska Stranding Hotline and/or by email to the Alaska 
Regional Stranding Coordinator, within 24 hours of the discovery. The 
City of Juneau would provide photographs, video footage (if available), 
or other documentation of the stranded animal sighting to NMFS and the 
Marine Mammal Stranding Coordinator.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    As stated in the proposed mitigation section, shutdown zones equal 
to or exceeding Level A isopleths shown in Table 7 for all activities 
other than blasting will be implemented. Serious injury or mortality is 
not anticipated nor authorized. Behavioral responses of marine mammals 
to pile removal and dredging, if any, are expected to be mild and 
temporary due to the short term duration of the noise produced by the 
source as well as the relatively low source levels when compared with 
ambient levels in an area with high levels of anthropogenic activity. 
Given the short duration of noise-generating activities per day and 
that pile removal and dredging would occur for 55 days, any harassment 
would be temporary. The blasting is only proposed to occur across 2 
days, with one blast scheduled on each day. In addition, the project 
includes generally low level sound sources, such as dredging and 
removal of piles much smaller than those frequently used in other 
construction projects. In addition, for all species except humpbacks, 
there are no known biologically important areas near the project zone 
that would be impacted by the construction activities. The region of 
Statter Harbor where the project will take place is located in a 
developed harbor area with regular marine vessel traffic. Although 
there is a resident harbor seal population, the area proposed for 
construction is not known to be of important biological significance 
such as used for breeding or foraging. 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;
     There are no known biologically important areas within the 
project area;
     The City of Juneau would implement mitigation measures 
such as shut down zones for all in-water and over-water activities;
     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 Sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. Additionally, other qualitative 
factors may be considered in the analysis, such as the temporal or 
spatial scale of the activities.
    Table 8 below shows take as a percent of population for each of the 
species listed above.

  Table 8--Summary of the Estimated Numbers of Marine Mammals Potentially Exposed to Level A and Level B Sound
                                                     Levels
----------------------------------------------------------------------------------------------------------------
                                                     Proposed        Proposed
                                                     number of       number of         Stock        Percent of
            Species                 DPS/Stock      level B takes   level A takes     abundance     population\1\
                                                     by stock        by stock
----------------------------------------------------------------------------------------------------------------
Steller sea lion..............  Eastern DPS.....           3,930              20          41,638             9.5
                                Western DPS.....              80               0          53,303            0.15
Harbor seal...................  Lynn Canal......           1,794              22           9,478              19
Harbor porpoise...............  Southeast Alaska              68               4             975            6.67
Humpback whale................  Central North                 24               0          10,103            0.24
                                 Pacific Stock.
    Total.....................  ................           5,897              46             N/A             N/A
----------------------------------------------------------------------------------------------------------------

    Table 8 presents the number of animals that could be exposed to 
received noise levels that may result in Level A or Level B take for 
the proposed work at Statter Harbor. Our analysis shows that less than 
one third of the

[[Page 52414]]

best available population estimate of each affected stock could be 
taken. Therefore, the numbers of animals authorized to be taken for all 
species would be considered small relative to the relevant stocks or 
populations even if each estimated taking occurred to a new 
individual--an extremely unlikely scenario. For pinnipeds, especially 
harbor seals and Steller sea lions, occurring in the vicinity of the 
project site, there will almost certainly be some overlap in 
individuals present day-to-day, and these takes are likely to occur 
only within some small portion of the overall regional 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

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. The proposed 
project is not known to occur in an important subsistence hunting area. 
It is a developed area with regular marine vessel traffic and the 
project is one year of a multi-year harbor improvement effort that is 
already underway. The work at this harbor has been publicized and 
public input has been solicited on the overall improvement.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there will 
not be an unmitigable adverse impact on subsistence uses from the City 
of Juneau's proposed 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 NMFS Alaska Regional 
Office, whenever we propose to authorize take for endangered or 
threatened species.
    NMFS is proposing to authorize take of western DPS Steller sea 
lions and potentially Mexico DPS humpback whales, which are listed 
under the ESA. We have requested initiation of Section 7 consultation 
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 the City of Juneau for conducting harbor improvement 
activities in Statter Harbor, Alaska, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. 
This section contains a draft of the IHA itself. The wording contained 
in this section is proposed for inclusion in the IHA (if issued).
    1. This Incidental Harassment Authorization (IHA) is valid from 
January 1, 2019 to December 31, 2019.
    2. This IHA is valid only for in-water construction activities 
associated with improvements in Statter Harbor, Alaska.
    3. General Conditions
    (a) A copy of this IHA must be in the possession of the City of 
Juneau, its designees, work crew, and marine mammal monitoring 
personnel operating under the authority of this IHA.
    (b) The species authorized for taking are humpback whale (Megaptera 
novaeangliae), harbor porpoise (Phocoena phocoena), Steller sea lion 
(Eumetopias jubatus), and harbor seal (Phoca vitulina).
    (c) The taking, by Level A and Level B harassment, is limited to 
the species listed in condition 3(b). See Table 9 for numbers of take 
authorized.
    (d) For those marine mammals for which take has not been requested, 
in-water activities must shut down immediately when the animals are 
sighted.
    (e) The taking by serious injury or death of any species of marine 
mammal is prohibited and may result in the modification, suspension, or 
revocation of this IHA.
    (f) The City of Juneau must conduct briefings between construction 
supervisors and crews, marine mammal monitoring team, and the City of 
Juneau staff prior to the start construction activity, and when new 
personnel join the work, in order to explain responsibilities, 
communication procedures, marine mammal monitoring protocol, and 
operational procedures.
    (g) Work may only occur during daylight hours.
    4. Mitigation Measures
    The holder of this Authorization is required to implement the 
following mitigation measures:
    (a) Shutdown Measures.
    (i) The City of Juneau must implement shutdown measures if the 
number of any allotted marine mammal takes reaches the limit under the 
IHA and if such marine mammals are sighted within the vicinity of the 
project area and are approaching their respective Level A or Level B 
monitoring zone.
    (ii) If a marine mammal comes within 10 meters of in-water, heavy 
machinery work, operations must cease and vessels must reduce speed to 
the minimum level required to maintain steerage and safe working 
conditions. Construction crew members can enforce this shutdown zone.
    (b) The City of Juneau must establish Level A and Level B 
monitoring zones as shown in Table 10.
    (c) The City of Juneau must monitor the zone for 30 minutes prior 
to blasting to establish that the monitoring zone is clear of marine 
mammals as long as practicable. Blasting-related activity must be 
conducted in daylight hours.
    5. Monitoring
    The holder of this Authorization is required to conduct marine 
mammal monitoring during construction activities. Monitoring and 
reporting must be conducted in accordance with the Monitoring Plan.
    (a) Pre-Activity Monitoring
    (i) Prior to the start of daily in-water construction activity, or 
whenever a break in construction activity of 30 minutes or longer 
occurs, the observer(s) must observe the shutdown and monitoring zones 
for a period of 30 minutes.
    (ii) The shutdown zone must be cleared when a marine mammal has not 
been observed within that zone for that 30-minute period.
    (iii) If a marine mammal is observed within the shutdown zone, 
activities can proceed if the animal is observed leaving the zone or 
has not been observed for 30 minutes, even if visibility of Level B 
zone is impaired.
    (iv) If the Level B harassment zone has been observed for 30 
minutes and species for which take is not authorized are not present 
within the zone, in-water construction can commence and work can 
continue even if visibility becomes impaired within the Level B zone.
    (v) When a marine mammal permitted for Level B take is present in 
the Level B harassment zone, pile removal and dredging activities may 
begin and or

[[Page 52415]]

continue and Level B take must be recorded.
    (vi) If the entire Level B zone is not visible while work 
continues, exposures must be recorded and extrapolated based upon the 
amount of total observed exposures and the percentage of the Level B 
zone that was not visible.
    (b) Monitoring must be conducted by qualified protected species 
observers (PSOs), with minimum qualifications as described previously 
in the Monitoring and Reporting section.
    (i) Two observers must be on site to actively observe the shutdown 
and monitoring zones during all pile removal and dredging.
    (ii) Observers must use their naked eye with the aid of binoculars, 
and/or a spotting scope during all construction activities.
    (iii) Monitoring location(s) must be identified with the following 
characteristics:
    1. Unobstructed view of activity being conducted;
    2. Unobstructed view of all water within the Level A zone (if 
applicable) and as much of the Level B harassment zone as possible.
    (c) If environmental conditions restrict the PSOs ability to 
observe within the marine mammal shutdown zone (e.g., excessive wind or 
fog), construction activities must cease. Work must not be initiated 
until the entire shutdown zone is visible.
    (d) Marine mammal location must be determined using a rangefinder 
and a GPS or compass.
    (e) Ongoing in-water work may be continued during periods when 
conditions such as low light, darkness, high sea state, fog, ice, rain, 
glare, or other conditions prevent effective marine mammal monitoring 
of the entire Level B harassment zone. PSOs would continue to monitor 
the visible portion of the Level B harassment zone throughout the 
duration of construction activities.
    (f) Post-activity monitoring must be conducted for 30 minutes 
beyond the cessation of construction activities at end of day.
    6. Reporting
    The holder of this Authorization is required to:
    (a) Submit a draft report on all monitoring conducted under the IHA 
within ninety calendar days of the completion of marine mammal 
monitoring This report must detail the monitoring protocol, summarize 
the data recorded during monitoring, and estimate the number of marine 
mammals that may have been harassed, including the total number 
extrapolated from observed animals across the entirety of relevant 
monitoring zones A final report must be prepared and submitted within 
thirty days following resolution of comments on the draft report from 
NMFS. This report must contain the following:
    (i) Date and time a monitored activity begins or ends;
    (ii) Construction activities occurring during each observation 
period;
    (iii) Record of implementation of shutdowns, including the distance 
of animals to the activity and description of specific actions that 
ensued and resulting behavior of the animal, if any;
    (iv) Weather parameters (e.g., percent cover, visibility);
    (v) Water conditions (e.g., sea state, tide state);
    (vi) Species, numbers, and, if possible, sex and age class of 
marine mammals;
    (vii) Description of any observable marine mammal behavior 
patterns;
    (viii) Distance from construction activities to marine mammals and 
distance from the marine mammals to the observation point;
    (ix) Locations of all marine mammal observations; and
    (x) Other human activity in the area;
    (b) Reporting injured or dead marine mammals:
    (i) In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by this IHA, 
such as a serious injury or mortality, The City of Juneau must 
immediately cease the specified activities and report the incident to 
the Office of Protected Resources, NMFS, and the Alaska Regional 
Stranding Coordinator, NMFS. The report must include the following 
information:
    1. Time and date of the incident;
    2. Description of the incident;
    3. Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    4. Description of all marine mammal observations and active sound 
source use in the 24 hours preceding the incident;
    5. Species identification or description of the animal(s) involved;
    6. Fate of the animal(s); and
    7. Photographs or video footage of the animal(s). Activities must 
not resume until NMFS is able to review the circumstances of the 
prohibited take. NMFS must work with the City of Juneau to determine 
what measures are necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. The City of Juneau may not 
resume their activities until notified by NMFS.
    (ii) In the event that the City of Juneau discovers an injured or 
dead marine mammal, and the lead observer determines that the cause of 
the injury or death is unknown and the death is relatively recent 
(e.g., in less than a moderate state of decomposition), the City of 
Juneau must immediately report the incident to the Office of Protected 
Resources, NMFS, and the Alaska Regional Stranding Coordinator, NMFS. 
The report must include the same information identified in 6(b)(i) of 
this IHA. Activities may continue while NMFS reviews the circumstances 
of the incident. NMFS must work with the City of Juneau to determine 
whether additional mitigation measures or modifications to the 
activities are appropriate.
    (iii) In the event that the City of Juneau discovers an injured or 
dead marine mammal, and the lead observer determines that the injury or 
death is not associated with or related to the activities authorized in 
the IHA (e.g., previously wounded animal, carcass with moderate to 
advanced decomposition, or scavenger damage), the City of Juneau must 
report the incident to the Office of Protected Resources, NMFS, and the 
Alaska Regional Stranding Coordinator, NMFS, within 24 hours of the 
discovery. The City of Juneau must provide photographs, video footage, 
or other documentation of the stranded animal sighting to NMFS.
7. Authorization
    This Authorization may be modified, suspended or withdrawn if the 
holder fails to abide by the conditions prescribed herein, or if NMFS 
determines the authorized taking is having more than a negligible 
impact on the species or stock of affected marine mammals.

                               Table 9--Authorized Take Numbers, by Species/Stocks
----------------------------------------------------------------------------------------------------------------
                  Species                                 DPS/Stock                Level A takes   Level B takes
----------------------------------------------------------------------------------------------------------------
Steller sea lion...........................  Eastern DPS........................              20           3,930
                                             Western DPS........................               0              80

[[Page 52416]]

 
Harbor seal................................  Lynn Canal.........................              22           1,794
Harbor porpoise............................  Southeast Alaska...................               4              68
Humpback whale.............................  Hawaii DPS/Central North Pacific                  0              24
                                              Stock.
                                                                                 -------------------------------
    Total..................................  ...................................              46           5,897
----------------------------------------------------------------------------------------------------------------


                                                        Table 10--Monitoring Zones in Meters (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           Monitoring zones                                            Shutdown zones
                                    --------------------------------------------------------------------------------------------------------------------
               Source                    High frequency
                                            cetacean         Low frequency cetacean          Phocid                Otariid              All species
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Removal--Steel...........  1,820 m...............  1,820 m...............  1,820 m..............  1,820 m..............  10 m
Vibratory Removal--Timber..........  1,360 m...............  1,360 m...............  1,360 m..............  1,360 m..............  10 m
Dredging...........................  110 m.................  110 m.................  110 m................  110 m................  10 m
Blasting (PTS).....................  160 m.................  180 m.................  80 m.................  10 m.................  10 m
Blasting (TTS).....................  340 m.................  990 m.................  410 m................  60 m.................  10 m
--------------------------------------------------------------------------------------------------------------------------------------------------------

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 harbor 
improvement activities. We also request comment on the potential for 
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 our final decision on the request for MMPA 
authorization.
    On a case-by-case basis, NMFS may issue a second one-year IHA 
without additional notice when (1) another year of identical or nearly 
identical activities as described in the Specified Activities section 
is planned or (2) the activities would not be completed by the time the 
IHA expires and a second IHA would allow for completion of the 
activities beyond that described in the Dates and Duration section, 
provided all of the following conditions are met:
     A request for renewal is received no later than 60 days 
prior to expiration of the current IHA;
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted beyond the 
initial dates either are identical to the previously analyzed 
activities or include changes so minor (e.g., reduction in pile size) 
that the changes do not affect the previous analyses, take estimates, 
or mitigation and monitoring requirements; and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized; and
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures remain the same and appropriate, 
and the original findings remain valid.

    Dated: October 11, 2018.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2018-22604 Filed 10-16-18; 8:45 am]
 BILLING CODE 3510-22-P