Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Confined Rock Blasting Near Ketchikan, Alaska, 11508-11528 [2019-05826]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 84, Number 59 (Wednesday, March 27, 2019)]
[Notices]
[Pages 11508-11528]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-05826]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG737


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Confined Rock Blasting Near 
Ketchikan, Alaska

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; request for comments.

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SUMMARY: NMFS has received a request from City of Ketchikan for 
authorization to take marine mammals incidental to underwater confined 
rock blasting in Ketchikan, Alaska. Pursuant to the Marine Mammal 
Protection Act (MMPA), NMFS is requesting comments on its proposal to 
issue an incidental harassment authorization (IHA) to incidentally take 
marine mammals during the specified activities. NMFS is also requesting 
comments on a possible one-year renewal that could be issued under 
certain circumstances and if all requirements are met, as described in 
Request for Public Comments at the end of this notice. NMFS will 
consider public comments prior to making any final decision on the 
issuance of the requested MMPA authorizations and agency responses will 
be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than April 
26, 2019.

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

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

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are 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 definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

National Environmental Policy Act

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

Summary of Request

    On December 10, 2018, NMFS received a request from the City of 
Ketchikan for an IHA to take marine mammals incidental to underwater 
confined blasting and excavation in southeastern Alaska. The 
application was deemed adequate and complete on February 7, 2019. City 
of Ketchikan's request is for take of a small number of nine marine 
mammal species by Level B harassment and three marine mammal species by 
Level A harassment. Neither the City of Ketchikan nor NMFS expects 
serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.

[[Page 11509]]

Description of Proposed Activity

Overview

    The City of Ketchikan proposes to conduct underwater confined 
blasting of a rock pinnacle in the Tongass Narrows, southeastern 
Alaska. Removal of the underwater pinnacle will expand the area of safe 
navigation depths for cruise ships that presently visit Berths I and 
II. Removing the pinnacle will provide a more reliable ingress and 
egress for ships over a much wider range of wind and water level 
conditions. The project is planned to occur from September 2019 through 
April 2020, and the action has the potential to affect waters in the 
Tongass Narrows and nearby Revillagigedo Channel, approximately 3 miles 
to the south.

Dates and Duration

    The project is scheduled to occur from September 16, 2019 through 
April 30, 2020, but the blasting portion of the activities is expected 
to occur between November 15, 2019 and March 15, 2020. This work window 
will avoid periods of known salmon and eulachon spawning, minimizing 
impact on these species and on marine mammals who may be attracted to 
these prey sources. Blasting is only planned for 50 days, so it will 
not occur each day during that period. Blasting will occur once per 
day, with the blast lasting approximately one second a day, and only 
during daylight hours.

Specific Geographic Region

    The City of Ketchikan is located in Southeast Alaska. The proposed 
activities will take place offshore from cruise ship Berth II in 
Ketchikan, Alaska, on the Tongass Narrows water-body (see Figure 1 of 
IHA application). Berth II is located in the southeastern portion of 
Ketchikan, opposite Pennock Island and near the mouth of Ketchikan 
Creek. The rock pinnacle to be removed sits in the channel between 
Pennock Island and the City of Ketchikan on Revillagigedo Island 
approximately 1,000 feet (ft) (305 meters (m)) west of Berth II. The 
immediate area is part of the Port of Ketchikan, an active marine 
commercial and industrial area.
    The region of activity originates in the Tongass Narrows and 
extends southeast into the Revillagigedo Channel (approximately 3.1 
miles (5 km) from Ketchikan). Impacts from all project activities are 
not expected to extend further than about three miles northeast of the 
City, where underwater noise would be impeded by landmasses.

Detailed Description of Specific Activity

Blasting
    A submerged rock pinnacle sits in the channel off of Berth II, 
limiting vessel navigation during low tide and high wind conditions. An 
underwater rock pinnacle near the cruise ship docks must be removed to 
allow ship traffic proper access in and out of the berths. This 
pinnacle, roughly 320 ft (97.5 m) by 150 ft (45.7 m), requires blasting 
for removal to a depth of approximately 42 ft (12.8 m) mean lower low 
water (MLLW).
    Work includes equipment mobilization, drilling of small boreholes 
(less than 8 inches), rock pinnacle removal through blasting, dredging 
of blasted material and transport of the material to an appropriate 
upland stockpile or placement site, and equipment demobilization. 
Boreholes will be drilled through casings and from stationary barges, 
held on site by spuds and/or anchors. NMFS has authorized take in 
association with certain types of drilling in other projects, (83 FR 
53217, October, 22, 2018), but those typically have much larger holes 
being drilled and/or other circumstances leading to an expectation of 
louder sound levels than are expected here. Because of the small 
borehole size, acoustic impacts from drilling are not expected to rise 
to the level of a take, and take is not proposed to be authorized for 
drilling activities, so its impacts are discussed minimally in this 
document.
    There will be up to 50 days of blasting (currently anticipating 
between 25 and 50 total blasts) limited to at most, one blast per day. 
A blast consists of a detonation of a series of sequential charges, 
delayed from one another at an interval of 8 milliseconds (ms), with 
the total blast typically lasting less than 1 second (one second = 1000 
milliseconds). Each delayed charge in the blast will contain a maximum 
of 75 total lbs (34 kg) of explosive. The timing of the blast must 
assure that the maximum pounds per delay does not exceed 75 lbs. The 
proposed daily blast will consist of a grid of boreholes, each 
containing a delayed charge (total number may vary but typically it 
ranges between 30 to 60 holes), with the top section of the hole then 
filled in with stone (this process is referred to as ``rock 
stemming''). This borehole grid pattern would have a minimal spacing of 
four ft between each charge, but this spacing could increase to six or 
more feet based on observations of how the rock is responding to 
blasting. For the purposes of impact modeling, four foot spacing was 
assumed as this minimal distance results in the most conservative 
impact zone estimates. Rock stemming locks the explosive material into 
the borehole to assure that most of the resulting energy enters the 
surrounding rock rather than the water column. This mitigates, or 
reduces, the blast energy released into the water. When the blast is 
detonated, each small borehole is triggered in a sequential manner to 
optimize rock fragmentation while minimizing underwater overpressure. 
This sequence is also important in reducing the amount of energy 
required to fracture the rock.
    The use of multiple boreholes, confinement of the blast (rock 
stemming), and use of planned sequential delays, all help to direct the 
blast energy into the rock rather than the water column. Other best 
management practices (BMPs) include adherence to a winter in-water work 
window to avoid fish spawning periods (September 16, 2019 through April 
30, 2020), accurate drilling, minimal blast duration, and limiting the 
blasts to a maximum of one per day. The project will adhere to all 
federal and state blasting regulations, which includes the development 
and adherence to blasting plans, monitoring, and reporting. All of the 
proposed BMPs support the reduction of potential adverse impacts on 
protected species from in-water noise and overpressure.
Dredging
    Dredging of the approximately 7,500 cubic yards (approximately 5734 
m\3\) of material freed by blasting will occur to bring the area to 
approximately -42 ft MLLW. Material will be removed and placed at the 
placement site using either a mechanical dredge or excavator deployed 
on a stationary barge. Material will be transported to an appropriate 
upland stock pile or placement site. While dredge material is removed 
and placed, barges will be held stationary by spuds and/or anchors.
    Dredging is considered to be a low-impact activity for marine 
mammals, producing non-pulsed sound and being substantially quieter in 
terms of acoustic energy output than sources such as seismic airguns 
and impact pile driving. Noise produced by dredging operations has been 
compared to that produced by a commercial vessel travelling at modest 
speed (Robinson et al., 2011). Further discussion of dredging sound 
production may be found in the literature (e.g., Richardson et al., 
1995, Nedwell et al., 2008, Parvin et al., 2008, Ainslie et al., 2009). 
Because dredging is expected to produce sounds similar to daily port 
activities, a marine mammal would not be expected to react to the sound 
nor subsequently be harassed. Therefore, the effects of dredging on

[[Page 11510]]

marine mammals are not expected to rise to the level of a take. As 
stated, take is highly unlikely and is not proposed to be authorized 
for dredging activities, so its impacts are discussed minimally in this 
document.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
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/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 1 lists all species with expected potential for occurrence in 
waters near Ketchikan, Alaska and summarizes information related to the 
population or stock, including regulatory status under the MMPA and ESA 
and potential biological removal (PBR), where known. For taxonomy, we 
follow Committee on Taxonomy (2018). PBR is defined by the MMPA as the 
maximum number of animals, not including natural mortalities, that may 
be removed from a marine mammal stock while allowing that stock to 
reach or maintain its optimum sustainable population (as described in 
NMFS's SARs). While no mortality is anticipated or authorized here, PBR 
and annual serious injury and mortality from anthropogenic sources are 
included here as gross indicators of the status of the species and 
other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. Alaska SARs (e.g., Muto et al., 2018). All values presented 
in Table 1 are the most recent available at the time of publication and 
are available in the 2017 SARs (Muto et al., 2018) and draft 2018 SARs 
(available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                                          Table 1--Marine Mammals That Could Occur in the Proposed Survey Areas
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                                                                                                            Stock abundance Nbest,
                                                                                        ESA/ MMPA status;   (CV, Nmin, most recent             Annual M/
             Common name                  Scientific name            MMPA stock        Strategic (Y/N) \1\   abundance survey) \2\     PBR       SI \3\
 
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Eschrichtiidae:
    Gray Whale......................  Eschrichtius robustus..  Eastern North Pacific.  -, -, N              26,960 (0.05, 25,849,         801        138
                                                                                                             2016).
Family Balaenidae:
    Humpback whale..................  Megaptera novaeangliae.  Central North Pacific.  E, D,Y               10,103 (0.3; 7,890;            83         25
                                                                                                             2006).
    Minke whale.....................  Balaenoptera             Alaska................  -, N                 N.A...................       N.A.       N.A.
                                       acutorostrata.
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                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer whale....................  Orcinus orca...........  Alaska Resident.......  -, N                 2,347 (N.A.; 2,347;            24          1
                                                                                                             2012).
                                                               West Coast Transient..  -, N                 243 (N.A., 243, 2009).        2.4          0
                                                               Northern Resident.....  -, N                 261 (N.A; 261; 2011)..       1.96          0
                                                               Gulf of Alaska          -, N                 587 (N.A.; 587; 2012).       5.87          1
                                                                Transient.
    Pacific white-sided dolphin.....  Lagenorhynchus           North Pacific.........  -, -; N              26,880 (N.A.; N.A.;          N.A.          0
                                       obliquidens.                                                          1990).
Family Phocoenidae:
    Harbor porpoise.................  Phocoena phocoena......  Southeast Alaska......  -, Y                 975 (0.10; 896; 2012).       8.95         34
    Dall's porpoise.................  Phocoenoides dalli.....  Alaska................  -, N                 83,400 (0.097, N.A.,         N.A.         38
                                                                                                             1993).
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                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion................  Eumetopias jubatus.....  Eastern U.S...........  -, -, N              41,638 (N.A.; 41,638;       2,498        108
                                                                                                             2015).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina           Clarence Strait.......  -, N                 31,634 (N.A.; 29,093;       1,222         41
                                       richardii.                                                            2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.


[[Page 11511]]

    All species that could potentially occur in the proposed survey 
areas are included in Table 1. As described below, all 9 species (with 
12 managed stocks) temporally and spatially co-occur with the activity 
to the degree that take is reasonably likely to occur, and we have 
proposed authorizing it. In addition, the northern sea otter (Enhydra 
lutris) may be found in waters near Ketchikan, Alaska. However, 
northern sea otters are managed by the U.S. Fish and Wildlife Service 
and are not considered further in this document.

Harbor Seals

    The Clarence Strait stock of harbor seals is not classified as a 
strategic stock (Muto et al., 2017). Harbor seals occurring near 
Ketchikan belong to the Clarence Strait harbor seal stock. Harbor seals 
belonging to the Clarence Strait stock have maintained an increasing 
population over the past 5 years. The latest stock assessment analysis 
indicates that the Clarence Strait population trend is an increase of 
921 seals per year, with a low probability (21 percent) that the stock 
is decreasing based on 5-year trend analysis (Muto et al., 2018).
    Harbor seals inhabit coastal and estuarine waters off Baja 
California; north along the western coasts of the United States, 
British Columbia, and Southeast Alaska; west through the Gulf of Alaska 
and Aleutian Islands; and in the Bering Sea north to Cape Newenham and 
the Pribilof Islands. They haul out on rocks, reefs, beaches, and 
drifting glacial ice, and feed in marine, estuarine, and occasionally 
fresh waters (Muto et al., 2017).
    Harbor seals are common in the inside waters of southeastern 
Alaska. There are no documented long-term haulout sites for harbor 
seals in Tongass Narrows; seasonal foraging is known to occur at the 
mouth of Ketchikan Creek (See Figure 2 in IHA Application), typically 
during late summer/early fall pink salmon runs (See IHA Application). 
Harbor seals are known to occupy the Ketchikan harbor directly adjacent 
to the planned pinnacle removal. Daily sightings of low numbers of 
harbor seals in the immediate vicinity of the project are common.

Steller Sea Lion

    The Steller sea lion is the largest of the eared seals, ranging 
along the North Pacific Rim from northern Japan to California, with 
centers of abundance and distribution in the Gulf of Alaska and 
Aleutian Islands. Steller sea lions were listed as threatened range-
wide under the ESA on November 26, 1990 (55 FR 49204). Subsequently, 
NMFS published a final rule designating critical habitat for the 
species as a 20 nautical mile buffer around all major haulouts and 
rookeries, as well as associated terrestrial, air and aquatic zones, 
and three large offshore foraging areas (58 FR 45269; August 27, 1993). 
In 1997, NMFS reclassified Steller sea lions as two distinct population 
segments (DPS) based on genetic studies and other information (62 FR 
24345; May 5, 1997). Steller sea lion populations that primarily occur 
west of 144[deg] W (Cape Suckling, Alaska) comprise the western DPS 
(wDPS), while all others comprise the eastern DPS (eDPS); however, 
there is regular movement of both DPSs across this boundary (Jemison et 
al., 2013). Due to the distance from this DPS boundary, NMFS is only 
considering eastern DPS Steller sea lions as present in the action 
area. Therefore, animals potentially affected by the project are 
assumed to be part of the eastern stock and the western stock is not 
discussed here.
    Steller sea lions range along the North Pacific Rim from northern 
Japan to California, with centers of abundance and distribution in the 
Gulf of Alaska and Aleutian Islands. Large numbers of individuals 
disperse widely outside of the breeding season (late May to early 
July), thus potentially intermixing with animals from other areas, 
probably to access seasonally important prey resources (Muto et al., 
2017).
    The current total population for the eastern stock is estimated at 
71,562 (Johnson and Fritz 2014) with the U.S. portion of that stock 
totaling 41,638 and the southeast Alaska region supporting 28,594 
eastern Steller sea lions (Muto et al., 2018). Modeling reporting in 
the most recent stock assessment indicates population growth of 4.76 
percent per year between 1989 and 2015.
    There are several mapped and regularly monitored long-term Steller 
sea lion haulouts surrounding Ketchikan, such as Grindall island 
(approximately 20 miles from Ketchikan), West Rocks (36 miles), or Nose 
Point (37 miles), but none within Tongass Narrows (Fritz et al., 2015). 
Sea lions are rarely observed in the Tongass narrows during the winter 
(See IHA Application). Fritz et al. (2015) reported adult counts at 
Grindall Island, located approximately 20 miles away from the project 
area, averaged about 190 between 2002 and 2015. No pups were recorded 
during this timeframe. West Rock averaged over 650 adults with 0 to 3 
pups observed over the same timeframe. These long-term and seasonal 
haulouts are important habitat for Steller sea lions, but all are 
outside of the action area.
    Grindall Island is approximately 20 miles outside of the portion of 
the action area where sound from the blasting is expected to rise to 
the level of take, north and west of the Tongass Narrows. Given that 
sea lion presence in Tongass Narrows mostly occurs during the Chinook 
run, outside of the in-water work window, and the nearest haulout site 
is outside of the action area, it is expected that Steller sea lion 
exposure to pinnacle blasting will be low. This has been confirmed by 
local observers, who have reported one to three sea lions in the 
Tongass Narrows near Ketchikan during the Chinook run, and otherwise 
rarely observed any.
    In summary, Steller sea lions are common throughout the inside 
waters of southeast Alaska and reside in areas nearby Tongass Narrows, 
however are not commonly observed in Tongass Narrows outside of the 
Chinook run. However due to the proximity of the Grindall Island 
haulout and the possibility of Steller sea lion movement around this 
haulout, they are potentially present year-round within the action 
area.

Harbor Porpoise

    Because the abundance estimates are 12 years old and the frequency 
of incidental mortality in commercial fisheries is not known, the 
Southeast Alaska stock of harbor porpoise is classified as a strategic 
stock (Muto et al., 2017).
    There are three harbor porpoise stocks in Alaska including the 
Southeast Alaska stock, Gulf of Alaska stock, and the Bering Sea stock. 
Only the Southeast Alaska stock occurs in the project vicinity. A 
review of survey data collected from 2010 through 2012 calculated an 
abundance estimate of 975 harbor porpoises (Dahlheim et al., 2015). 
This estimate was split into the northern and southern portion of the 
unit and only included inside waters of southeast Alaska. Harbor 
porpoise abundance in the southern portion, including Ketchikan, is 
estimated to be 577. However, this number is likely biased low due to 
survey methodology (Muto et al., 2017).
    Older abundance surveys which included both coastal and inside 
waters of southeast Alaska resulted in an observed abundance estimate 
of 3,766 porpoise (Hobbs and Waite 2010). Correction factors for 
observer perception bias and porpoise availability at the surface were 
used to develop an estimated corrected abundance of 11,146 harbor 
porpoise in both the coastal and inside waters of Southeast Alaska.

[[Page 11512]]

    Harbor porpoise primarily frequent coastal waters, and in the Gulf 
of Alaska and Southeast Alaska, they occur most frequently in waters 
less than 100 meters (Dahlheim et al., 2009). Within the inland waters 
of Southeast Alaska, the harbor porpoise distribution is clumped, with 
greatest densities observed in the Glacier Bay/Icy Strait region, and 
near Zarembo and Wrangell Islands and the adjacent waters of Sumner 
Strait (Muto et al., 2017).
    Harbor porpoise are spotted sporadically from marine tour ships 
around Ketchikan (See IHA Application). One sighting every three weeks 
was reported, typically north of the Tongass Narrows in Behm Canal. The 
duration of these animals remaining in the area is unknown. The mean 
group size of harbor porpoise in Southeast Alaska is estimated at two 
individuals (Dahlheim et al., 2009). Therefore, while less common 
within the Tongass Narrows than nearby areas, harbor porpoise could 
potentially pass through the area and/or occupy the Revillagigedo 
Channel year-round.

Humpback Whales

    The humpback whale is distributed worldwide in all ocean basins. In 
winter, most humpback whales occur in the subtropical and tropical 
waters of the Northern and Southern Hemispheres, and migrate to high 
latitudes in the summer to feed (Johnson and Wolman 1984).
    Under the MMPA, there are three stocks of humpback whales in the 
North Pacific: (1) The California/Oregon/Washington and Mexico stock, 
consisting of winter/spring populations in coastal Central America and 
coastal Mexico which migrate to the coast of California to southern 
British Columbia in summer/fall; (2) the central North Pacific stock, 
consisting of winter/spring populations of the Hawaiian Islands which 
migrate primarily to northern British Columbia/Southeast Alaska, the 
Gulf of Alaska, and the Bering Sea/Aleutian Islands; and (3) the 
western North Pacific stock, consisting of winter/spring populations 
off Asia which migrate primarily to Russia and the Bering Sea/Aleutian 
Islands. The central north Pacific stock is the only stock that is 
found near the project activities.
    On September 8, 2016, NMFS published a final rule dividing the 
globally listed endangered species into 14 DPSs under the ESA, removing 
the worldwide species-level listing, and in its place listing four DPSs 
as endangered and one DPS as threatened (81 FR 62259; effective October 
11, 2016). Two DPSs (Hawaii and Mexico) are potentially present within 
the action area (Wade et al., 2016). This study found a strong majority 
of whales present in the area belong to the delisted Hawaii DPS, while 
less than 10 percent of the whales expected within Southeast Alaska 
belong to the threatened Mexico DPS. Wade et al. (2016) calculated 
stock estimates for the newly recognized DPS's: 11,398 for Hawaii and 
3,264 for Mexico. Wade et al. (2016) reports a distribution of 93.9 
percent Hawaii DPS vs 6.1 percent Mexico DPS humpback whale observation 
percentage in Southeast Alaska and these relative abundance percentages 
are used in the analysis contained within this document.
    Humpback whales are the most commonly observed baleen whale in the 
area and surrounding Southeast Alaska, particularly during spring and 
summer months. Humpback whales in Alaska, although not limited to these 
areas, return to specific feeding locations such as Frederick Sound, 
Sitka Sound, Glacier Bay, Icy Straight, Lynn Canal, and Prince William 
Sound, as well as other similar coastal areas (Hendrix et al., 2011).
    Summertime observations show humpback whales commonly transit the 
Tongass Narrows, particularly in late May into June (See IHA 
Application). Wintertime observations are reported occasionally, though 
not annually. Humpback whales are most likely to occur in the action 
area during periods of seasonal prey aggregations which typically occur 
in spring and can occur in summer and fall (Freitag 2017, as cited in 
83 FR 22009, May 11, 2018). Herring salmon, eulachon, and euphausiids 
(krill) are among the species that congregate ephemerally (HDR 2003). 
When humpback whales come into the Narrows to feed, they often stay in 
the channel for a few days at a time (Freitag 2017).
    In conclusion, humpback whales could be present within the action 
area at any point during the year. They are most likely to occur 
seasonally during periods of prey aggregation, typically during the 
late spring and summer months.

Killer Whale

    Killer whales are found throughout the North Pacific. On the west 
coast of North America killer whales occur along the entire Alaskan 
coast, in British Columbia and Washington inland waterways, and along 
the outer coasts of Washington, Oregon, and California (Muto et al., 
2017). Seasonal and year-round occurrence has been noted for killer 
whales throughout Alaska and in the intracoastal waterways of British 
Columbia and Washington State, where whales have been labeled as 
``resident,'' ``transient,'' and ``offshore'' type killer whales based 
on aspects of morphology, ecology, genetics and behavior.
    Killer whales occurring near Ketchikan could belong to one of four 
different stocks: Eastern North Pacific Alaska resident stock (Alaska 
residents); Eastern North Pacific Northern resident stock (Northern 
residents); Gulf of Alaska, Aleutian Islands, and Bering Sea transient 
stock (Gulf of Alaska transients); or West Coast transient stock (Muto 
et al., 2017). The Northern resident stock is a transboundary stock, 
and includes killer whales that frequent British Columbia, Canada, and 
southeastern Alaska (Muto et al., 2018).
    In recent years, a small number of the Gulf of Alaska transients 
(identified by genetics and association) have been seen in southeastern 
Alaska; previously only West Coast transients had been seen in 
southeastern Alaska (Muto et al., 2017). Therefore, the Gulf of Alaska 
transient stock occupies a range that includes southeastern Alaska. 
Photo-identification studies have identified 587 individual whales in 
this stock.
    The West Coast transient stock includes animals that occur in 
California, Oregon, Washington, British Columbia and southeastern 
Alaska. Analysis of photographic data identifies 243 individual 
transient killer whales, however this minimum population size estimate 
does not include whales that belong to this stock but occur in 
California or the ``outer coast'' portion of the stock (Muto et al., 
2017).
    Local citizens (See IHA Application) report that killer whale pods 
frequent the Tongass Narrows area, with a peak abundance of 20 to 30 
during the Chinook salmon run, however the work window is not expected 
to align with major times of fish spawning. Transient killer whales are 
known to prey on marine mammals (Muto et al., 2018), so their presence 
may be less dependent on fish spawning runs. Still, wintertime 
observations are less common, with a group of five whales reported 
transiting the narrows in winter 2016/2017, but none the following 
winter as of January 2018. Despite being rare in occurrence during the 
proposed time of construction (pods expected to absent more often than 
present), it must be acknowledged that killer whales often travel in 
pods and would occur as such if they were to occur at all in the 
project area. Typical pod sizes observed within the Tongass Narrows 
area range from 1 to 10 animals and the frequency of killer whales 
passing through the action area is estimated to be once per month 
(Solstice 2018, as cited in 83 FR 37473,

[[Page 11513]]

August 1, 2018). For the purposes of this request we estimate that a 
group of five whales (pod) may occur near the action area occasionally. 
While we are assuming a group size in the middle of the expected range, 
we are assuming a higher frequency of group occurrence (See ``Estimated 
Take'' section below). Due to the wide variety of life history 
strategies of the different killer whale populations, they could be 
present within the action area at any time throughout the year.

Dall's Porpoise

    Dall's porpoise are widely distributed across the entire North 
Pacific Ocean. Throughout most of the eastern North Pacific they are 
present during all months of the year, although there may be seasonal 
onshore-offshore movements along the west coast of the continental 
United States and winter movements of populations out of Prince William 
Sound and areas in the Gulf of Alaska and Bering Sea (Muto et al., 
2017).
    Dahlheim et al. (2009) found Dall's porpoise throughout Southeast 
Alaska, with concentrations of animals consistently found in Lynn 
Canal, Stephens Passage, Icy Strait, upper Chatham Strait, Frederick 
Sound, and Clarence Strait. Local observers do not report specific 
sightings of Dall's porpoise, which typically show a strong vessel 
attraction (Muto et al., 2017) making observations easy for a keen eye. 
The mean group size of Dall's porpoise in Southeast Alaska is estimated 
at approximately three individuals (Dahlheim et al., 2009; Jefferson et 
al., 2019), however, in the Ketchikan vicinity, Dall's porpoises are 
reported to typically occur in groups of 10-15 animals, with an 
estimated maximum group size of 20 animals (Freitag 2017, as cited in 
83 FR 22009, May 11, 2018). Jefferson et al. (2019) presents historical 
survey data showing few sightings in the Ketchikan area, and based on 
these occurrence patterns, concludes that Dall's porpoise rarely come 
into narrow waterways, like Tongass Narrows. Overall, sightings of 
Dall's porpoise are infrequent near Ketchikan, but they could be 
present on any given day during the construction period.

Minke Whale

    In the North Pacific minke whales occur from the Bering and Chukchi 
Seas south to near the Equator (Muto et al., 2017). Dahlheim et al. 
(2009) observed minke whales during the spring and summer, with 
multiple sightings near the north end of Clarence Strait and one 
observation near the Dixon entrance. Observations were concentrated 
near the entrance to Glacier Bay, far north of the work area. Local 
observers do not report observations of minke whales, and that they are 
considered rare in waters around Ketchikan. The Alaska stock of minke 
whales occurs in Southeast Alaska. At this time, it is not possible to 
produce a reliable estimate of minimum abundance for this wide-ranging 
stock. No estimates have been made for the number of minke whales in 
the entire North Pacific. Surveys in 2001-2003 of an area ranging from 
Kenai Fjords in the Gulf of Alaska to the central Aleutian Islands 
estimate 1,233 animals (Zerbini et al., 2006). 2010 surveys on the 
eastern Bering Sea shelf included 1,638 kilometer of effort and provide 
a provisional estimate of 2,020 whales (Friday et al., 2013). Neither 
of these estimates corrected for animals missed on the trackline and 
only surveyed a portion of the stock's range. Due to lacking abundance 
estimates the current minimum population number is considered unknown. 
While considered rare within the vicinity, minke whales could enter the 
action area at any time throughout the year.

Gray Whale

    The Eastern North Pacific (ENP) stock of gray whale was delisted 
from the ESA in 1994 (NMFS 1994). It is not listed as ``depleted'' 
under the MMPA. Crossover in range between the ESA-endangered Western 
North Pacific (WNP) stock is considered rare, though not unheard of. 
Various tagging, photo-identification, and genetic studies showed 27 to 
30 whales identified in the WNP off Russia have been observed in the 
ENP, including the coastal waters of Canada, the United States, and 
Mexico (Carretta et al., 2017, Caretta et al., 2019 DRAFT). These WNP 
gray whales are not expected to be present during the proposed 
activity, because the project occurs primarily during late fall to 
early spring. At this time, gray whales are generally in their 
wintering grounds, with the WNP primarily overwintering in the Western 
Pacific (Carretta et al., 2017).
    The ENP stock of gray whale primarily spends summer and autumn in 
Chukchi, Beaufort and northwestern Bering Seas, but some members of the 
group can occupy the waters between Kodiak Island down to Northern 
California during this time (Carretta et al., 2017). Winter migration 
brings these animals to Baja California, Mexico. Population size is 
calculated based on migrating whales counted as they pass the central 
California coast; the most recent estimate of ENP abundance is 20,990 
(Durban et al., 2013). A photographic mark-recapture study 
(Calambokidis et al., 2014) calculated an abundance estimate for the 
PCFG of 209 whales. The population size has been stable or increasing 
over the last several decades (Muto et al., 2017).
    A study of gray whale abundance from Northern California to British 
Columbia (Calambokidis et al., 2014) analyzed seasonal timing and 
abundance of ENP gray whales over 13 years (1998 through 2010). Whales 
were sighted every day, however very few during December through 
February when most whales are in or migrating to Mexico. During this 
study period, 25 whales were reported in the entire Southeast Alaska 
region, five of which occurred in November, within the proposed 
construction window (November to March).
    Gray whales are not generally reported by Ketchikan residents. A 
gray whale entering the Tongass Narrows appears highly unlikely, 
however a gray whale could migrate through or near the Dixon Entrance 
during November, and possibly travel up the Nichols Channel into the 
action area as it extends into the Revillagigedo Channel.
    A gray whale sighting within the action area would be considered 
extremely rare, however they could travel up the Revillagigedo Channel 
during the work period.

Pacific White-Sided Dolphin

    Pacific white-sided dolphin are not designated as ``depleted'' 
under the MMPA nor listed as ``threatened'' or ``endangered'' under the 
ESA. Because Pacific white-sided dolphin are considered common in the 
waters of Alaska and because the number of human-related removals is 
currently thought to be minimal, this stock is not a strategic stock 
(Muto et al., 2017).
    Pacific white-sided dophins (North Pacific Stock) have an estimated 
population size of 26,880 in the most recent stock assessments (2018). 
Surveys for the Alaska stock of Pacific white-sided dolphin were 
conducted in the late 1980s and early 1990s (Buckland et al., 1993) and 
more recently in 2005, 2006, 2014 and 2016. The abundance estimate is 
based on recently published report by NMFS (James et al., 2018).
    Dalheim et al. (2009) frequently encountered Pacific white-sided 
dolphin in Clarence Strait with significant differences in mean group 
size and rare enough encounters to limit the seasonality investigation 
to a qualitative note that spring featured the highest number of 
animals observed. These observations were noted most typically in open 
strait environments, near the open ocean. Mean group size

[[Page 11514]]

was over 20, with no recorded winter observations nor observations made 
in the Nichols Passage or Behm Canal, located on either side of the 
Tongass Narrows.
    Though generally preferring more pelagic, open-water environments, 
Pacific white-sided dolphin could be present within the action area 
during the construction period.

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. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 2.

                  Table 2--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Nine marine mammal species (seven 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, three are classified as low-
frequency cetaceans (i.e., all mysticete species), two are classified 
as mid-frequency cetaceans (i.e., all delphinid and ziphiid species and 
the sperm whale), and two are classified as high-frequency cetaceans 
(i.e., harbor porpoise and Kogia spp.).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

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

Description of Sound

    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 hertz (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 (sound pressure level 
[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

[[Page 11515]]

(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 
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 Sound Sources

    In-water construction activities associated with the project would 
include dredging, borehole drilling, 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 by 
spectral property. The sounds produced by the City of Ketchikan's 
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.
    Explosives used for blasting emit 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 and small diameter, 
borehole drilling, that would consistently emit noise for an extended 
period of time and increase vessel traffic in the Tongass Narrows. 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 other

[[Page 11516]]

common industrial noise sources at a working port, such as Tongass 
Narrows. Because dredging is expected to produce sounds similar to 
daily port activities, a marine mammal would not be expected to react 
to the sound nor subsequently be harassed. Based on this, NMFS does not 
generally authorize take for dredging activities, including this 
project, where dredging will occur in a busy port. Additionally, while 
take has been authorized associated with drilling activities in other 
IHAs (83 FR 53217, October 22, 2018), these have been for larger 
diameter drilling associated with piles. The borehole drilling 
associated with blasting is small diameter, and as such, are not 
thought to be dissimilar to other common industrial noise sources at a 
working port, such as Tongass Narrows. Because borehole drilling is 
expected to produce sounds similar to daily port activities, a marine 
mammal would not be expected to react to the sound and therefore would 
not experience harassment. Based on this, NMFS feels it is not 
necessary to authorize take for these drilling activities.

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 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 Ketchikan's 
blasting 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., certain non-auditory 
physical or physiological effects) only briefly as we do not expect 
that there is a reasonable likelihood that the City of Ketchikan'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 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 (SEL) 
thresholds are 15 to 20 dB higher than TTS cumulative SEL 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

[[Page 11517]]

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. We note Reichmuth et al. 
(2016) attempted to induce TTS in an additional two species of 
pinnipeds (ringed seal and spotted seal); however, they were 
unsuccessful. 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 Ketchikan'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 (though this energy is reduced 
by as much as 60-90 percent by confining the blast as the City of 
Ketchikan plans to do). 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 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. Therefore, given the low 
weight of the charges, confined nature of the blasts, and small size of 
the detonation relative to large open water detonations in conjunction 
with monitoring and mitigation measures discussed below, the City of 
Ketchikan's 25 to 50 blasting events are not likely to have severe 
injury or mortality effects on marine mammals in the project vicinity. 
Instead, NMFS considers that the City of Ketchikan's blasts are most 
likely to cause TTS (Level B harassment) in a few individual marine 
mammals, but there could be limited non-lethal injury and PTS (Level A 
harassment) in three species, as discussed below.

Behavioral Effects

    Based on the near instantaneous nature of blasting, if only single 
blast is being conducted each day, NMFS does not expect behavioral 
disturbance to occur. The City of Ketchikan's proposed blasting is a 
single blast, composed of charges separated by microdelays 
(approximately 8 ms), and therefore behavioral disturbance is not 
expected to occur. As a result, because single detonation blasting is 
the only proposed activity for which take is expected to occur, 
behavioral disturbance is only discussed briefly below.
    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

[[Page 11518]]

involving marine mammal behavioral responses to sound.

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 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 and Pressure Effects, Underwater

    The effects of sounds and blasting pressure waves from the City of 
Ketchikan's proposed activities might include one or more of the 
following: Temporary or permanent hearing impairment and non-auditory 
physical or physiological effects, however the near instantaneous 
nature of blasting activity and planned single blast per day means 
behavioral disturbance is not likely to occur (Richardson et al., 1995; 
Gordon et al., 2003; Nowacek et al., 2007; Southall et al., 2007). The 
effects of underwater detonations on marine mammals are dependent on 
several factors, including the size, type, and depth of the animal; the 
depth, intensity, and duration of the sound; the depth of the water 
column; the substrate of the habitat; the standoff distance between 
activities and the animal; and the sound propagation properties of the 
environment. Thus, we expect impacts to marine mammals from the 
confined blasting activities to result primarily from acoustic 
pathways.
    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 and because only one blast will occur 
each day, behavioral disturbance is not expected to occur and TTS is 
the most likely effect from the proposed activity. This short duration 
of elevated noise is not expected to result in meaningful behavioral 
disturbance that constitutes take. PTS constitutes injury, but TTS does 
not (Southall et al., 2007). Due to the use of mitigation measures 
discussed in detail in the Proposed Mitigation section, it is unlikely 
but possible that PTS could occur from blasting. Marine mammals would 
need to be within a relatively small radius (size dependent on hearing 
group) of the blast to experience PTS.

Anticipated Effects on Marine Mammal Habitat and Prey

    Blasting will permanently impact habitat directly offshore from the 
Ketchikan waterfront. The rock pinnacle area to be removed is roughly 
320 ft by 150 ft square with an average of 4 ft in height. Appendix B 
of the IHA application details the configuration of this feature. 
Vertical benthic structure provides habitat for a variety of fish and 
prey species and would be removed during this portion of the project. 
However, the surrounding area is heavily trafficked by large and small 
ships and is not a significant foraging ground for marine mammals. 
Removal of this submerged pinnacle would not impact growth and/or 
survival of marine mammal populations.
    Construction activities will have temporary impacts on marine 
mammal habitat through increases in in-water and in-air sound from 
underwater blasting. Construction activities that increase in-water 
noise, have the potential to adversely affect forage fish and juvenile 
salmonids in the project area. Forage fish species are part of the prey 
base for marine mammals. Adult salmon are a part of the prey base for 
Steller sea lions, harbor seals, and killer whales. Forage fish and 
salmonids may alter their normal behavior during pinnacle blasting and 
associated activities. In-water construction timing, between September 
16, 2019 and April 30, 2020, has been planned to avoid major spawning 
and migration times. After pinnacle blasting and associated activities 
are completed habitat use and function is expected to return to pre-
construction levels.
    The City of Ketchikan's blasting activities would produce 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. Avoidance by 
potential prey (i.e., fish, certain marine mammals) 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

[[Page 11519]]

normal recruitment, distribution and behavior is anticipated. Any 
behavioral avoidance by fish of the disturbed area would still leave 
sufficiently large areas of fish and marine mammal foraging habitat in 
waters southeast and northeast of Tongass Narrows.
    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.
    While impacts from blasting to fish have the potential to be 
severe, including barotrauma and mortality, the blasts will last 
approximately one second on 25 to 50 days, making the duration of 
activity that could cause this impact short term. In general, impacts 
to marine mammal prey species are expected to be minor and the window 
for them to occur is temporary due to the short timeframe for the 
project.
    Additionally, the presence of transient killer whales means some 
marine mammal species are also possible prey (harbor seals, harbor 
porpoises). The City of Ketchikan's blasting activities are expected to 
result in limited instances of TTS and minor PTS on these smaller 
marine mammals. That, as well as the fact that the City of Ketchikan is 
impacting a small portion of the total available marine mammal habitat 
means that there will be minimal impact on these marine mammals as 
prey.
    For the most part, adverse effects on prey species during project 
construction will be short-term, based on the short duration of the 
project. Given the numbers of fish and other prey species in the 
vicinity, the short-term nature of effects on fish species and the 
mitigation measures to protect fish and marine mammals during 
construction, the proposed project is not expected to have measurable 
effects on the distribution or abundance of potential marine mammal 
prey species.
    Other potential temporary impacts are on water quality (increases 
in turbidity levels) and on prey species distribution. BMPs and 
minimization practices used by the City of Ketchikan to minimize 
potential environmental effects from project activities are outlined in 
``Proposed Mitigation.''
    The most likely effects on marine mammal habitat from the proposed 
project will be a minor alteration of benthic habitat and temporary, 
short-duration noise, and water and sediment quality effects. The 
direct loss of habitat available to marine mammals during construction 
due to noise, water quality impacts, sediment quality impacts, and 
construction activity is expected to be minimal and return to pre-
blasting conditions shortly after blasting is completed. After pinnacle 
blasting is completed habitat use and function in the general area are 
expected to return to pre-blasting levels, despite the removal of the 
underwater pinnacle feature. Impacts to habitat and prey are expected 
to be minimal based on the short duration of activities.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment (via 
TTS), as use of the explosive source (i.e., blasting) for a very short 
period each day has the potential to result in TTS for individual 
marine mammals. There is also some potential for auditory injury and 
slight tissue damage (Level A harassment) to result, primarily for 
mysticetes, porpoise, and phocids because predicted auditory injury 
zones are larger than for mid-frequency cetaceans and otariids. The 
proposed mitigation and monitoring measures are expected to minimize 
the severity of such taking to the extent practicable. The primary 
relevant mitigation measure is avoiding blasting when any marine mammal 
is observed in the PTS zone. While this measure should avoid all take 
by Level A harassment, NMFS is authorizing takes by Level A harassment 
to account for the possibility that marine mammals escape observation 
in the PTS zone. Additionally, while the zones for slight lung injury 
are large enough that a marine mammal could occur within the zone (42 
meters), the mitigation and monitoring measures, such as avoiding 
blasting when marine mammals are observed in PTS zone, are expected to 
minimize the potential for such taking to the extent practicable. 
Therefore the potential for non-auditory physical injury is considered 
discountable, and all takes by Level A harassment are expected to occur 
due to PTS.
    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 incur some degree of 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 incur TTS 
(equated to Level B harassment) or PTS (equated to Level A harassment) 
of some degree. 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. TTS 
is possible and Table 3 lists TTS onset thresholds.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). The City 
of Ketchikan's proposed activity includes the use of an impulsive 
source, blasting.
    These thresholds are provided in Table 3 below. Table 3 also 
provides

[[Page 11520]]

threshold for tissue damage and mortality. The references, analysis, 
and methodology used in the development of the thresholds are described 
in NMFS 2016 Technical Guidance, which may be accessed at: https://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

                                         Table 3--Explosive Acoustic and Pressure Thresholds for Marine Mammals
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Level B harassment             Level A harassment             Serious injury
                                 ----------------------------------------------------------------------------------------------------
              Group                    Behavioral                                                                                          Mortality
                                       (multiple               TTS                  PTS              Gastro-             Lung
                                      detonations)                                              intestinal tract
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-freq cetacean...............  163 dB SEL.........  168 dB SEL or 213    183 dB SEL or 219   237 dB SPL......  39.1M1/3 (1+[D/     91.4M1/3 (1+[D/
                                                        dB SPLpk.            dB SPLpk.          ................   10.081])1/2 Pa-     10.081])1/2 Pa-
                                                                                                                   sec.                sec
                                                                                                                  where: M = mass of  where: M = mass of
                                                                                                                   the animals in kg.  the animals in kg
                                                                                                                  D = depth of        D = depth of
                                                                                                                   animal in m.        animal in m.
Mid-freq cetacean...............  165 dB SEL.........  170 dB SEL of 224    185 dB SEL or 230
                                                        dB SPLpk.            dB SPLpk.
High-freq cetacean..............  135 dB SEL.........  140 dB SEL or 196    155 dB SEL or 202
                                                        dB SPLpk.            dB SPLpk.
Phocidae........................  165 dB SEL.........  170 dB SEL or 212    185 dB SEL or 218
                                                        dB SPLpk.            dB SPLpk.
Otariidae.......................  183 dB SEL.........  188 dB SEL or 226    203 dB SEL or 232
                                                        dBpk.                dB SPLpk.
--------------------------------------------------------------------------------------------------------------------------------------------------------

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.
    Blasting--While the NMFS Technical Guidance (2016) and associated 
User Spreadsheet include tools for predicting threshold shift isopleths 
for multiple detonations, the Marine Mammal Commission noted in 
response to a previous proposed IHA (83 FR 52394, October 17, 2018) 
that the User Spreadsheet contained some errors in methodology for 
single detonations. Following a method generated through consultation 
with the Marine Mammal Commission, NMFS computed cumulative sound 
exposure impact zones from the blasting information provided by the 
City of Ketchikan. Peak source levels of the confined blasts were 
calculated based on Hempet et al. (2007), using a distance of 4 feet 
and a weight of 75 pounds for a single charge. The total charge weight 
is defined as the product of the single charge weight and the number of 
charges. In this case, the maximum number of charges is 60. Explosive 
energy was then computed from peak pressure of the single maximum 
charge, using the pressure and time relationship of a shock wave (Urick 
1983). Due to time and spatial separation of each single charge by a 
distance of four feet, the accumulation of acoustic energy is added 
sequentially, assuming the transmission loss follows cylindrical 
spreading within the matrix of charges. The SEL from each charge at its 
source can then be calculated, followed by the received SEL from each 
charge. Since the charges will be deployed in a grid with a least 4 ft 
by 4 ft spacing, the received SELs from different charges to a given 
point will vary depending on the distance of the charges from the 
receiver. As stated in the ``Detailed Description of Specific 
Activity,'' the actual spacing between charges will be determined based 
on how the rock responds to the blasting. Modeling was carried out 
using 4 ft spacing as this closest potential spacing results in the 
most conservative (highest) source values and largest resulting impact 
zones. Without specific information regarding the layout of the 
charges, the modeling assumes a grid of 7 by 8 charges with an 
additional four charges located in peripheral locations. Among the 
various total SELs calculated, the largest value, SELtotal(max) is 
selected to calculate the impact range. Using the pressure versus time 
relationship (Urick 1983), the frequency spectrum of the explosion can 
be computed by taking the Fourier transform of the pressure (Weston, 
1960). Frequency specific transmission loss of acoustic energy due to 
absorption is computed using the absorption coefficient, [alpha] (dB/
km), summarized by Fran[ccedil]ois and Garrison (1982a, b). Seawater 
properties for computing sound speed and absorption coefficient were 
based on Ketchikan ocean temperatures recorded from November through 
March (National Centers for Environmental Information, 2018) and 
salinity data presented in Vanderhoof and Carls (2012). Transmission 
loss was calculated using the sonar equation:

TL = SELtotal(m) - SELthreshold

where SELthreshold is the Level A harassment and Level B 
harassment (TTS) threshold. The distances, R, where such transmission 
loss is achieved were computed numerically by combining both geometric 
transmission loss, and transmission loss due to frequency-specific 
absorption. A spreading coefficient of 20 is assumed. While this 
spreading coefficient would normally indicate an assumption of 
spherical spreading, in this instance, the higher coefficient is 
actually used to account for acoustic energy loss from the sediment 
into the water column. The outputs from this model are summarized in 
Table 4 below. For the dual criteria of SELcum and SPLpk shown in Table 
4, distances in bold are the larger of the two isopleths, and were used 
in further analysis. Because the blast is composed of multiple charges 
arranged in a grid, these distances are measured from any individual 
charge, meaning that measurement begins at the outermost charges. For 
additional information on these calculations please refer to the 
``Ketchikan Detonation Modeling Concept'' document which can be found 
at the following address: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

[[Page 11521]]



                                            Table 4--Model Results of Impact Zones for Blasting in Meters (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Slight lung
       Marine Mammal Hearing Group          Mortality *      injury *        GI Tract       PTS: SELcum     PTS: SPLpk      TTS: SELcum     TTS: SPLpk
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low frequency cetacean..................               6              12              24          ** 430             188           2,350             375
Mid frequency cetacean..................              14              31              24              90              53             430             106
High frequency cetacean.................              18              42              24            1420            1328           5,000           2,650
Otariid.................................              12              28              24              30            **42             150              84
Phocid..................................              16              37              24             210             211           1,120             420
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Estimates for Mortality and Slight lung injury are based on body size of each individual species, so multiple estimates exist for some marine mammal
  hearing groups. The value entered into the table is the most conservative (largest isopleth) calculated for that group.

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. Expected marine mammal presence is determined by past 
observations and general abundance near the Ketchikan waterfront during 
the construction window. The take requests for this IHA were estimated 
using local marine mammal data sets (e.g., National Marine Mammal 
Laboratory databases; Dahlheim et al., 2009) and observations from 
local Ketchikan charter operators and residents. A recent IHA and 
associated application for nearby construction (83 FR 37473, August 1, 
2018) was also reviewed to identify marine mammal group size and 
potential frequency of occurrence within the project vicinity.
Harbor Seals
    Low numbers of harbor seals are a common observation around the 
Ketchikan waterfront, and likely utilize other, less developed 
nearshore habitats within and adjacent to the Level B harassment zone. 
Harbor seals can occur in the project area year-round with an estimated 
maximum group size of three animals (83 FR 37473, August 1, 2018, 
Solstice 2018), and up to three groups of three animals occurring daily 
in the Level B harassment (TTS) zone (1,120 meters). Additionally, 
harbor seals could occasionally be found in the Level A harassment 
(PTS) zone.
Steller Sea Lions
    Known Steller sea lion haulouts are well outside of the pinnacle 
blasting Level B harassment zone. However, Steller sea lions are 
residents of the wider vicinity and could be present within the Level B 
harassment zone on any given day of construction. Steller sea lion 
observations in the project area typically include groups composed of 
up to 10 animals (83 FR 37473, August 1, 2018, Solstice 2018), with one 
group potentially present each day.
Harbor Porpoise
    Based on observations of local boat charter captains and watershed 
stewards, harbor porpoise are infrequently encountered in the Tongass 
Narrows, and more frequently in the nearby larger inlets and Clarence 
Strait. Therefore, they could potentially transit through both the 
Level B harassment zone and Level A harassment zone during a blasting 
event. They could occupy the Ketchikan waterfront and be exposed to the 
Level A harassment zone during transit between preferred habitats. 
Harbor porpoises observed in the project vicinity typically occur in 
groups of one to five animals with an estimated maximum group size of 
eight animals (83 FR 37473, August 1, 2018, Solstice 2018). For our 
impact analysis, we are considering a group to consist of five animals, 
a value on the high end of the typical group size. The frequency of 
harbor porpoise occurrence in the project vicinity is estimated to be 
one group passing through the area per month (83 FR 37473, August 1, 
2018, Solstice 2018), but, for our analysis, we conservatively consider 
a group of five animals could be present every five days (approximately 
once per week).
Humpback Whales
    Based on observations of local boat charter captains and watershed 
stewards, humpback whales regularly utilize the surrounding waters and 
are occasionally observed near Ketchikan, most often on a seasonal 
basis. Most observations occur during the summer with sporadic 
occurrences during other periods. The typical humpback whale group size 
in the project vicinity is between one and two animals observed at a 
frequency of up to three times per month (83 FR 37473, August 1, 2018, 
Solstice 2018), but conservatively, a group of two whales could be 
present every third day.
Killer Whales
    Killer whales could occur within the action area year-round. 
Typical pod sizes observed within the project vicinity range from 1 to 
10 animals and the frequency of killer whales passing through the 
action area is estimated to be once per month (83 FR 37473, August 1, 
2018, Solstice 2018). In this project, NMFS assumes a group of five 
whales will be present every fifth day (approximately once per week). 
Note that groups could be larger, but we expect that the overall number 
of takes proposed for authorization is sufficient to account for this 
possibility given the conservative assumption that a pod would be 
present once per week.
Dall's Porpoise
    Based on local observations and regional studies, Dall's porpoise 
are infrequently encountered in small numbers in the waters surrounding 
Ketchikan. This body of evidence is supported by Jefferson et al.'s 
(2019) presentation of historical survey data showing very few 
sightings in the Ketchikan area and conclusion that Dall's porpoise 
generally are rare in narrow waterways, like the Tongass Narrows. 
Tongass Narrows is not a preferred habitat, so if they are present, 
they would most likely be traveling between areas of preferred forage, 
which are not within the blasting work window. However, they could 
still potentially transit through the Level B or Level A harassment 
zone infrequently during blasting. Typical Dall's porpoise group sizes 
in the project vicinity range from 10 to 15 animals observed roughly 
once per month (83 FR 37473, August 1, 2018, Solstice 2018). In this 
project, NMFS assumes a group of 10 Dall's porpoises could be present 
every 10th day, or approximately every other week.
Minke Whale
    Based on observations of local marine mammal specialists, the 
possibility of minke whales occurring in the Tongass Narrows is rare. 
Minke whales are generally observed individually or in groups of up to 
three animals. This, along with scientific survey data showing that 
this species has not been

[[Page 11522]]

documented within the vicinity, indicates that there is little risk of 
exposure to blasting. However, the accessible habitat in the 
Revillagigedo Channel leaves the potential that minke whale could enter 
the action area. NFMS assumes that a group of two whales may be present 
every tenth day, or approximately every other week.
Gray Whale
    No gray whales were observed during surveys of the inland waters of 
southeast Alaska conducted between 1991 and 2007 (Dahlheim et al., 
2009). It is possible that a migrating whale may venture up Nichols 
Passage and enter the underwater Level B harassment zone. NMFS 
estimates that one whale may be present every tenth day, or 
approximately every two weeks.
Pacific White-Sided Dolphin
    Dolphins are regularly seen within Clarence Strait but have been 
reported to prefer larger channel areas near open ocean. Their presence 
within the Tongass Narrows has not been reported. They are not expected 
to enter the Tongass Narrows toward their relatively small injury zone, 
so no take by Level A harassment is requested. Pacific white-sided 
dolphin group sizes generally range from between 20 and 164 animals. 
For the purposes of this assessment we assume one group of 20 dolphins 
may be present within the Level B harassment zone every tenth day, or 
about every other week.

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate. Incidental take is 
estimated for each species by considering the likelihood of a marine 
mammal being present within the Level A or B harassment zone during a 
blasting event. Expected marine mammal presence is determined by past 
observations and general abundance near the Ketchikan waterfront during 
the construction window, as described above. The calculation for marine 
mammal exposures is estimated by the following two equations:

Level B harassment estimate = N (number of animals) x number of days 
animals are expected within Level B harassment zones for blasting
Level A harassment estimate = N (number of animals) x number of days 
animals are expected to occur within the Level A harassment zone 
without being observed by PSOs

    For many species, the equation may also include a term to factor in 
the frequency a group is expected to be seen, which is explained within 
the paragraphs for that species.
Harbor Seals
    We conservatively estimate that three groups of three harbor seals 
could be present within the Level B harassment zone on each day of 
construction and two additional harbor seals could be present within 
the Level A harassment zone on each day of construction. Because take 
estimates are based on anecdotal occurrences, including these 
additional individual harbor seals that could occur in the Level A 
harassment zone is another conservative assumption. Potential airborne 
disturbance would be accounted for by the Level B harassment zone, 
which covers a wider distance. Using these estimates the following 
number of harbor seals are estimated to be present through the 
construction period.

Level B harassment: Three groups of animals x three animals per group x 
50 blasting days = 450
Level A harassment: Two animals x 50 days of blasting = 100
Steller Sea lions
    We conservatively estimate that a group of 10 sea lions could be 
present within the Level B harassment zone on any given day of 
blasting. No exposure within the blasting Level A harassment zone is 
expected based on the small size of this zone and behavior of the 
species in context of the proposed mitigation. The Level A harassment 
zones can be effectively monitored during the marine mammal monitoring 
program and prevent take by Level A harassment. Using these estimates 
the following number of Steller sea lions are estimated to be present 
in the Level B harassment zone:

Level B harassment: 10 animals daily over 50 blasting days = 500

    No take by Level A harassment was requested or is proposed to be 
authorized because the small Level A harassment zone can be effectively 
observed.
Harbor Porpoise
    We conservatively estimate and assume that a group of five harbor 
porpoise could be sighted in the Level B harassment zone every 5th day, 
or approximately once per week. Additionally, while the City of 
Ketchikan does not anticipate take by Level A harassment to occur, the 
cryptic nature of harbor porpoises and large Level A harassment 
isopleth mean the species could be in the Level A harassment zone 
without prior observation. Therefore, one additional group of 5 animals 
could be present in the Level A harassment zone every second week or 
10th day, a conservative assumption because this group is in addition 
to those anticipated in the Level B harassment zone.

Level B harassment: Five animals x 50 days of work divided by 5 
(frequency of occurrence) = 50
Level A harassment: Five animals x 50 days of work divided by 10 
(frequency of occurrence) = 25
Humpback Whale
    Based on occurrence information in the area, we conservatively 
estimate that a group of two humpback whales will be sighted within the 
Level B harassment zone every third day. The City is requesting 
authorization for 33 takes by Level B harassment of humpback whales. Of 
this number, we estimate 31 humpback whales will belong to the unlisted 
Hawaii DPS while three will belong to the ESA listed Mexico DPS based 
on the estimated occurrence of these DPSs (Wade et al., 2016). It 
should be noted that these estimates sum to 34, because take estimates 
were rounded up to avoid fractional takes of individuals in the DPSs.

Level B: Two animals x 50 days of work divided by 3 (frequency of 
occurrence) = 33.

    No take by Level A harassment was requested or is proposed to be 
authorized because these large whales can be effectively monitored and 
work can be shutdown when they are present.
Killer Whale
    Based on information presented above (Marine Mammal Occurrence) we 
conservatively estimate that a group of five whales may be sighted 
within the Level B harassment zone once every fifth day, or about once 
per week. Using this number, the following number of killer whales are 
estimated to be present within the Level B harassment zone:

Level B: Five animals x 50 days of work divided by 5 (frequency of 
occurrence) = 50

    No take by Level A harassment was requested or is proposed to be 
authorized because the relatively small Level A harassment zone can be 
effectively monitored to prevent take by Level A harassment.
Dall's Porpoise
    Based on information presented above (Marine Mammal Occurrence) we 
conservatively estimate and assume that a group of 10 Dall's porpoise 
could be sighted within the Level B harassment zone every tenth day, or 
about every

[[Page 11523]]

other week. Additionally, while the City of Ketchikan does not 
anticipate take by Level A harassment to occur, the large Level A 
isopleth mean the species could be in the Level A harassment zone 
without prior observation. Therefore, one additional group of 10 
animals could be present in the Level A harassment zone every month, 
which is a conservative assumption because this group is in addition to 
those anticipated in the Level B harassment zone.
    Using this assumption, the following number of Dall's porpoise are 
estimated to be present in the Level B harassment zone:

Level B harassment: 10 animals x 50 days of work divided by 10 
(frequency of occurrence) = 50
Level A harassment: 10 animals x 50 days of work divided by 20 
(frequency of occurrence) = 25; because this is a fraction of group, 
this number is rounded up to 30 to represent 3 full groups of Dall's 
porpoise
Minke Whale
    Based on information presented above (Marine Mammal Occurrence) we 
conservatively estimate that two minke whales may be sighted within the 
Level B harassment zone every tenth day, or about once every two weeks.

Level B harassment: Two animals x 50 days work divided by 10 (frequency 
of occurrence) = 10

    No take by Level A harassment was requested or is proposed to be 
authorized because the City of Ketchikan can effectively monitor for 
these whales and shutdown if are present in the Level A harassment 
zone.
Gray Whale
    Based on information presented above (Marine Mammal Occurrence) we 
conservatively estimate that one whale may be sighted within the Level 
B harassment zone every tenth day, or about every 2 weeks.

Level B harassment: One animal x 50 days work divided by 10 (frequency 
of occurrence) = 5

    No take by Level A harassment was requested or is proposed to be 
authorized because the City of Ketchikan can effectively monitor for 
these whales and shutdown if are present in the Level A harassment 
zone.
Pacific White-Sided Dolphin
    Based on the assumption that Pacific white-sided dolphins are not 
expected to enter Tongass Narrows, despite their regular occurrence in 
the Clarence Strait, we estimate that one group of 20 dolphins may be 
sighted within the Level B harassment zone every tenth day, or about 
every other week.

Level B harassment: 20 animals x 50 days of work divided by 10 
(frequency of occurrence) = 100

    No take by Level A harassment was requested or is proposed to be 
authorized because the relatively small Level A harassment zone can be 
effectively monitored in order to avoid take by Level A harassment.

                       Table 5--Proposed Take Estimates as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
                                                                                                    Percent of
                Species                       Stock (NEST)            Level A         Level B          stock
----------------------------------------------------------------------------------------------------------------
Humpback Whale........................  Hawaii DPS (11,398) \a\.               0          \a\ 31            0.34
                                        Mexico DPS (3,264) \a\..  ..............               3  ..............
Minke Whale...........................  Alaska (N/A)............               0              10             N/A
Gray Whale............................  Eastern North Pacific                  0               5            0.02
                                         (26,960).
Killer Whale..........................  Alaska Resident (2,347).               0              50            2.13
                                        Northern Resident (261).  ..............  ..............           19.16
                                        West Coast Transient      ..............  ..............           20.58
                                         (243).
                                        Gulf of Alaska Transient  ..............  ..............        \c\ 8.52
                                         (587).
Pacific White-Sided Dolphin...........  North Pacific (26,880)..               0             100            0.37
Dall's Porpoise.......................  Alaska (83,400).........              30              50            0.10
Harbor Porpoise.......................  Southeast Alaska (975)                25              50            7.69
                                         \b\.
Harbor Seal...........................  Clarence Strait (31,634)             100             450            1.74
Steller Sea Lion......................  Eastern U.S (41,638)....               0             500            1.20
----------------------------------------------------------------------------------------------------------------
\a\ Total estimated stock size for Central North Pacific humpback whales is 10,103. Under the MMPA humpback
  whales are considered a single stock (Central North Pacific); however, we have divided them here to account
  for DPSs listed under the ESA. Based on calculations in Wade et al. (2016), 93.9% of the humpback whales in
  Southeast Alaska are expected to be from the Hawaii DPS and 6.1% are expected to be from the Mexico DPS.
\b\ In the SAR for harbor porpoise (NMFS 2017), NMFS identified population estimates and PBR for porpoises
  within inland Southeast Alaska waters (these abundance estimates have not been corrected for g(0); therefore,
  they are likely conservative).
\c\ These percentages assume all 50 takes come from each individual stock, thus the percentage are likely
  inflated as multiple stocks are realistically impacted.

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

[[Page 11524]]

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.

Shutdown Zone for In-Water Heavy Machinery Work

    For in-water heavy machinery work (using, e.g., standard barges, 
tug boats, barge-mounted excavators, or equipment used to place or 
remove material), a minimum 10 meter shutdown zone shall be 
implemented. If a marine mammal comes within 10 meters of such 
operations, operations shall cease (safely) and vessels shall reduce 
speed to the minimum level required to maintain steerage and safe 
working conditions. This type of work could include (but is not limited 
to) the following activities: (1) Movement of blasting barge; (2) 
drilling of boreholes; (3) dredging of rubble; and (4) transport of 
dredge material. An operation that requires completion due to safety 
reasons (e.g., material actively being handled by excavator/clamshell), 
that singular operation will be allowed to be completed.

Additional Shutdown Zones and Monitoring Zones

    For blasting, the Level B harassment zone will be monitored for a 
minimum of 30 minutes prior to the planned blast, and continue for 30 
minutes after the blast. If a marine mammal with authorized take 
remaining is sighted within this monitoring zone, blasting can occur 
and take will be tallied against the authorized number of takes by 
Level B harassment. Data will be recorded on the location, behavior, 
and disposition of the mammal as long as the mammal is within this 
monitoring zone.
    The City of Ketchikan will establish a shutdown zone for a marine 
mammal species that is greater than its corresponding Level A 
harassment zone, as measured from any charge in the blasting grid. If 
any cetaceans or pinnipeds are observed within the shutdown zone, the 
blasting contractor would be notified and no blast would be allowed to 
occur until the animals are observed voluntarily leaving the shutdown 
zone or 15 minutes have passed without re-sighting the animal in the 
shutdown zone. When weather conditions prevent accurate sighting of 
marine mammals, blasting activities will not occur until conditions in 
the shutdown zone return to acceptable levels.

             Table 6--Blasting Shutdown and Monitoring Zones
------------------------------------------------------------------------
                                           Shutdown zone    Monitoring
       Marine mammal hearing group              (m)          zone (m)
------------------------------------------------------------------------
Low frequency ceteacean.................         * 1,000           2,500
Mid frequency ceteacean.................             100             500
High frequency cetacean.................           1,500           5,000
Otariid.................................           * 100             200
Phocid..................................             250           1,500
------------------------------------------------------------------------
Note: These distances are measured from the outermost points of the grid
  of charges that make up a blast.
* The City of Ketchikan expressed an opinion that the PTS distances for
  Otariids and LF cetaceans presented in Table 4 seemed
  uncharacteristically small when compared to the other thresholds
  resulting from the model. The PTS zones were therefore doubled to 84 m
  for Otariids and 860 m for LF cetaceans for purposes of mitigation and
  monitoring, resulting in the Shutdown Zones presented here.

    If blasting is delayed due to marine mammal presence, PSO's will 
continue monitoring for marine mammals during the delay. If blasting is 
delayed for a reason other than marine mammal presence, and this delay 
will be greater than 30 minutes, marine mammal monitoring does not need 
to occur during the delay. However, if monitoring is halted, a new 
period of the 30 minute pre-blast monitoring must occur before the 
rescheduled blast.

Timing and Daylight Restrictions

    In-water blasting work is expected to occur from November 15, 2019 
to March 15, 2020, but will be limited to September 16, 2019 to April 
30, 2020. Pinnacle blasting will be conducted during daylight hours 
(sunrise to sunset) to help ensure that marine mammal observers have 
acceptable conditions to survey the shutdown and monitoring zones. Non-
blasting activities, including but not limited to dredging and borehole 
drilling can occur outside of daylight hours, but the 10-meter general 
shutdown zone must be maintained.

Non-Authorized Take Prohibited

    If a marine mammal is observed within the monitoring zone and that 
species is either not authorized for take or its authorized takes are 
met, blasting must not occur. Blasting must be delayed until the animal 
has been confirmed to have left the area or an observation time period 
of 15 minutes has elapsed without seeing the marine mammal in the 
monitoring zone.

Blasting BMPs

    The City of Ketchikan will use industry BMPs to reduce the 
potential adverse impacts on protected species from in-water noise and 
overpressure. These include the use of multiple small boreholes, 
confinement of the blast (rock stemming), use of planned sequential 
delays, and all measures designed to help direct blast energy into the 
rock rather than the water column. Additional BMPs to minimize impact 
on marine mammals and other species include adherence to a winter in-
water work window, accurate drilling, shot duration, and limiting the 
blasts to a maximum of one per day. The project will adhere to all 
federal and state blasting regulations, which includes the development 
and adherence to blasting plans, monitoring, and reporting.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, 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

[[Page 11525]]

and reporting that will result in increased knowledge of the species 
and of the level of taking or impacts on populations of marine mammals 
that are expected to be present in the proposed action area. Effective 
reporting is critical both to compliance as well as ensuring that the 
most value is obtained from the required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density).
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas).
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors.
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks.
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat).
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Monitoring by NMFS-approved protected species observers (PSOs) will 
begin 30 minutes prior to a planned blast and extend through 30 minutes 
after the blast. This will ensure that all marine mammals in the 
monitoring zone are documented and that no marine mammals are present 
within the shutdown zone. Hauled out marine mammals within the shutdown 
and monitoring zones will be tallied and monitored closely. PSOs will 
be stationed at the best vantage points possible for monitoring the 
monitoring zone (see Figure 3 and 4 of the IHA application); however, 
should the entire zone not be visible, take will be extrapolated daily, 
based on anticipated marine mammal occurrence and documented 
observations within the portion of the monitoring zone observed.
    During blasting, there will be two land-based PSOs and one PSO on 
the barge used for blasting operations, with no duties other than 
monitoring. Establishing a monitoring station on the barge will provide 
the observer with an unobstructed view of the injury zones during 
blasting and direct communication with the operator.
    Land based PSOs will be positioned at the best practical vantage 
points based on blasting activities and the locations of equipment. The 
land-based observers will be positioned with a clear view of the 
remaining of the injury zone and will monitor the shutdown zones and 
monitoring zones with binoculars and a spotting scope. The land-based 
observers will communicate via radio to the lead monitor positioned on 
the barge. Specific locations of the observers will be based on 
blasting activities and the locations of equipment. Shore-based 
observers will be stationed along the outer margins of the largest 
shutdown zone.
    The monitoring position of the observers will be identified with 
the following characteristics:
    1. Unobstructed view of blasting area;
    2. Unobstructed view of all water within the shutdown zone;
    3. Clear view of operator or construction foreman in the event of 
radio failure (lead biologist); and
    4. Safe distance from activities in the construction area.
    Monitoring of blasting 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 curriculum vitae (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 
blasting 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.

Test Blast Monitoring

    While full hydroacoustic monitoring is not planned for this 
project, the City of Ketchikan will perform a minimum of one test blast 
to confirm underwater overpressure values. Overpressure will be 
measured during the test blast with hydrophones at pre-determined 
locations. This work will be performed by an experienced contractor 
with process documents, results, and the test blast report all being 
approved by a blasting consultant. For monitoring of this test blast, 
the City of Ketchikan will be required to record the following 
information:
     Hydrophone equipment and methods: recording device, 
sampling rate, distance of recording devices from the blast where 
recordings were made; depth of recording devices;
     Number of charges and the weight of each charge detonated 
during the blast; and
     Mean, median, and maximum sound levels (dB re: 1[micro]Pa) 
of SELcum and SPLpeak.

Reporting

    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of blasting 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:

[[Page 11526]]

     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.
    Additionally, the City of Ketchikan will submit the report and 
results of their test blast to NMFS prior to beginning production 
blasting. This report will include the information outlined in Test 
Blast Monitoring.
    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 
Ketchikan 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 
Ketchikan to determine what is necessary to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. The City of 
Ketchikan would not be able to resume their activities until notified 
by NMFS via letter, email, or telephone.
    In the event that the City of Ketchikan 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 Ketchikan 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 Ketchikan to determine whether modifications in the 
activities are appropriate.
    In the event that the City of Ketchikan discovers an injured or 
dead marine mammal and the lead PSO determines that the injury or death 
is not associated with or related to the activities authorized in the 
IHA (e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), the City of Ketchikan 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 
Ketchikan 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).
    To avoid repetition, our analysis applies to all species listed in 
Table 5, given that NMFS expects the anticipated effects of the 
proposed blasting to be similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, NMFS has identified species-specific factors to inform the 
analysis.
    NMFS does not anticipate that serious injury or mortality would 
occur as a result of the City of Ketchikan's proposed blasting. In the 
absence of proposed mitigation including shutdown zones, these impacts 
are possible, but at very short distances from the blasts (Table 4). 
NMFS feels that the mitigation measures stated in ``Proposed 
Mitigation,'' include adequate shutdown zones, marine mammal 
monitoring, and blasting BMPs sufficient to prevent serious injury or 
mortality. Thus, no serious injury or morality is proposed for 
authorization. As discussed in the Potential Effects section, non-
auditory physical effects are not expected to occur.
    The authorized number of takes by both Level A harassment and Level 
B harassment is given in Table 5. Take by Level A harassment is only 
proposed to be authorized for harbor seals, harbor porpoises, and 
Dall's porpoises. As stated in ``Proposed Mitigation'' the City of 
Ketchikan will establish shutdown zones, greater than Level A 
harassment zones for blasting, and a blanket 10 m shutdown zone will be 
implemented for all other in-water use of heavy machinery. The proposed 
authorization of take by Level A harassment is meant to account for the 
slight possibility that these species escape observation by the PSOs 
within the Level A harassment zone. Any take by Level A harassment is 
expected to arise from a small degree of PTS, because the isopleths 
related to PTS are consistently larger than those associated with 
slight lung and GI tract injury (Table 4).
    Blasting is only proposed to occur on a maximum of 50 days, with 
just one blast per day, from November 15, 2019

[[Page 11527]]

to March 15, 2020. Because only one blast is authorized per day, and 
this activity would only generate noise for approximately one second, 
no behavioral response that could rise to the level of take is expected 
to occur. Therefore, all takes by Level B harassment are expected to 
arise from TTS, but we expect only a small degree of TTS, which is 
fully recoverable and not considered injury.
    Although the removal of the rock pinnacle would result in the 
permanent alteration of habitat available for marine mammals and their 
prey, the affected area would be discountable. Overall, the area 
impacted by the project is very small compared to the available habitat 
around Ketchikan. The pinnacle is adjacent to an active marine 
commercial and industrial area, and is regularly disturbed by human 
activities. In addition, for all species except humpbacks, there are no 
known biologically important areas (BIA) near the project zone that 
would be impacted by the blasting activities. For humpback whales, 
Southeast Alaska is a seasonally important BIA from spring through late 
fall (Ferguson et al., 2015), however, Tongass Narrows is not an 
important portion of this habitat due to development and human 
presence. Additionally, the work window is not expected to overlap with 
periods of peak foraging, and the action area represents a small 
portion of available habitat. While impacts from blasting to fish can 
be severe, blasting will occur for a relatively short period of 50 
days, meaning the duration of impact should also be short. Any impacts 
on prey that would occur during that period would have at most short-
terms effects on foraging of individual marine mammals, and likely no 
effect on the populations of marine mammals as a whole. Therefore, 
indirect effects on marine mammal prey during the construction are not 
expected to be substantial, and these insubstantial effects would 
therefore be unlikely to cause substantial effects on marine mammals at 
the individual or population level.
    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 serious injury or mortality is anticipated or 
authorized;
     Blasting would not occur during fish runs, avoiding 
impacts during peak foraging periods;
     Only a very small portion of marine mammal habitat would 
be temporarily impacted;
     The City of Ketchikan would implement mitigation measures 
including shut down zones for all blasting and other in-water activity 
to minimize the potential for take by Level A harassment and the 
severity if it does occur; and
     TTS that will occur is expected to be of a small degree 
and is recoverable;
    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 5, in the Take Calculation and Estimation section, presents 
the number of animals that could be exposed to received noise levels 
that may result in take by Level A harassment or Level B harassment for 
the proposed blasting by the City of Ketchikan. Our analysis shows that 
at most, approximately 20.6 percent of the best population estimates of 
each affected stock could be taken, but for most species and stocks, 
the percentage is below 2 percent. There was one stock, minke whale, 
where the lack of an accepted stock abundance value prevented us from 
calculating an expected percentage of the population that would be 
affected. The most relevant estimate of partial stock abundance is 
1,233 minke whales for a portion of the Gulf of Alaska (Zerbini et al., 
2006). Given 10 authorized takes by Level B harassment for the stock, 
comparison to the best estimate of stock abundance shows less than 1 
percent of the stock is expected to be impacted. Therefore, the numbers 
of animals authorized to be taken for all species, including minke 
whale, would be considered small relative to the relevant stocks or 
populations even if each estimated taking occurred to a new 
individual--an unlikely scenario for pinnipeds, but a possibility for 
other marine mammals based on their described transit through Tongass 
Narrows. 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

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    In 2012, the community of Ketchikan had an estimated subsistence 
take of 22 harbor seals and 0 Steller sea lion (Wolf et al., 2013). 
Hunting usually occurs in October and November (Alaska Department of 
Fish and Game (ADF&G) 2009), but there are also records of relatively 
high harvest in May (Wolfe et al., 2013). All project activities will 
take place within the industrial area of Tongass Narrows immediately 
adjacent to Ketchikan where subsistence activities do not generally 
occur. The project will not have an adverse impact on the availability 
of marine mammals for subsistence use at locations farther away, where 
these activities are expected to take place. Some minor, short-term 
harassment of the harbor seals could occur, but this is not likely to 
have any measureable effect on subsistence harvest activities in the

[[Page 11528]]

region. Additionally, blasting associated with the project is expected 
to occur from November 15 to March 15. This means that blasting, and 
the associated harassment of marine mammals will only overlap with a 
small portion of the expected period of subsistence harvest. Based on 
the spatial separation and partial temporal separation of blasting 
activities and subsistence harvest, no changes to availability of 
subsistence resources are expected to result from the City of 
Ketchikan's proposed activities.
    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 City of 
Ketchikan'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 Office of Protected Resources 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 Mexico DPS humpback whales 
which are listed under the ESA. The NMFS Office of Protected Resources 
has requested initiation of Section 7 consultation with the NMFS Alaska 
Regional Office for the issuance of this IHA. NMFS will conclude the 
ESA section 7 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 Ketchikan for conducting blasting near 
Ketchikan, Alaska in 2019 and 2020, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. A 
draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed 
underwater blasting. 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 one-year IHA renewal with 
an expedited public comment period (15 days) 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 under the 
proposed Renewal are identical to the activities analyzed under the 
initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take 
because only a subset of the initially analyzed activities remain to be 
completed under the Renewal)..
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: March 21, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2019-05826 Filed 3-26-19; 8:45 am]
 BILLING CODE 3510-22-P