Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Ferry Berth Improvements in Tongass Narrows in Ketchikan, Alaska, 5980-6015 [2022-02035]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 87, Number 22 (Wednesday, February 2, 2022)]
[Notices]
[Pages 5980-6015]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-02035]



[[Page 5979]]

Vol. 87

Wednesday,

No. 22

February 2, 2022

Part III





Department of Commerce





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National Oceanic and Atmospheric Administration





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Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to Ferry Berth Improvements in Tongass 
Narrows in Ketchikan, Alaska; Notice

Federal Register / Vol. 87 , No. 22 / Wednesday, February 2, 2022 / 
Notices

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB709]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Ferry Berth Improvements in Tongass 
Narrows in Ketchikan, Alaska

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from the Alaska Department of 
Transportation and Public Facilities (ADOT) for an Incidental 
Harassment Authorization (IHA) to take marine mammals incidental to the 
construction of four ferry berth facilities in Tongass Narrows in 
Ketchikan, Alaska: The Gravina Airport Ferry Layup Facility, the 
Gravina Freight Facility, the Revilla New Ferry Berth, and the Gravina 
Island Shuttle Ferry Berth Facility. Pursuant to the Marine Mammal 
Protection Act (MMPA), NMFS is requesting comments on its proposal to 
issue an IHA to incidentally take marine mammals during the specified 
activities. NMFS is also requesting comments on a possible one-time, 
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 March 4, 
2022.

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

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

SUPPLEMENTARY INFORMATION:

Background

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

National Environmental Policy Act

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

Summary of Request

    On August 19, 2021, NMFS received a request from the ADOT for an 
IHA to take marine mammals incidental to the construction of two ferry 
berth facilities in Tongass Narrows in Ketchikan, Alaska: The Gravina 
Airport Ferry Layup Facility and the Gravina Freight Facility. On 
December 17, 2021 we received a revised request that included 
additional work components associated with the Revilla New Ferry Berth 
and Upland Improvements and the New Gravina Island Shuttle Ferry Berth 
and Related Terminal Improvements in the same region. The application 
was deemed adequate and complete on January 4, 2022. ADOT's request is 
for take of a small number of eight species of marine mammals, by Level 
B harassment and Level A harassment. Of those eight species, five 
(Steller sea lion (Eumetopias jubatus), harbor seal (Phoca vitulina 
richardii), harbor porpoise (Phocoena phocoena), Dall's porpoise 
(Phocoenoides dalli) and minke whale (Balaenoptera acutorostrata)) may 
also be taken by Level A harassment. Neither the ADOT nor NMFS expects 
serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.
    NMFS previously issued two consecutive IHAs and a Renewal IHA to 
ADOT for this work (85 FR 673, January 7, 2020; 86 FR 23938, May 05, 
2021).

[[Page 5981]]

ADOT complied with all the requirements (e.g., mitigation, monitoring, 
and reporting) of the previous IHAs and information regarding their 
monitoring results may be found in the Description of Marine Mammals in 
the Area of Specified Activities and Marine Mammal Occurrence and Take 
Calculation and Estimation sections. An IHA for the first phase of 
construction of the Ketchikan-Gravina Access Project was issued to ADOT 
on December 20, 2019 (85 FR 673, January 7, 2020). Complete 
construction of two of those components, the Revilla New Ferry Berth 
and Upland Improvements and Gravina Island Shuttle Ferry Berth 
Facility/Related Terminal Improvements, did not occur within the 
timeframe authorized by the Phase 1 IHA and will not be finished before 
the expiration of the subsequent one-year renewal (86 FR 23938, May 05, 
2021). Therefore, ADOT is requesting a new IHA for incidental take 
associated with the continued marine construction of these facilities. 
This proposed IHA would be valid for one year.

Description of Proposed Activity

Overview

    ADOT is making improvements to existing ferry berths and 
constructing new ferry berths on Gravina Island and Revillagigedo 
(Revilla) Island in Tongass Narrows, near Ketchikan in southeast Alaska 
(Figure 1). These ferry facilities provide the only public access 
between the city of Ketchikan, AK on Revilla Island, and the Ketchikan 
International Airport on Gravina Island (Figure 1). The project's 
proposed activities that have the potential to take marine mammals, by 
Level A harassment and Level B harassment, include vibratory and impact 
pile driving, down-the-hole (DTH) operations for pile installation 
(rock socketing of piles and tension anchors to secure piles), and 
vibratory pile removal. The marine construction associated with the 
proposed activities is planned to occur over 91 non-consecutive days 
over one year beginning March 2022.
    Improvement and construction of facilities is important to provide 
reliable access to the airport and facilitate growth and development in 
the region. Some of the existing ferry facilities are aging and 
periodically out-of-service for repairs or maintenance, and this 
project would provide redundant ferry berths to increase reliability. 
Ketchikan is Alaska's fifth largest city, with a population of 
approximately 8,125 (DCCED 2017), and has numerous marine facilities 
including fishing infrastructure, cruise and ferry terminals, and 
shipyards.
BILLING CODE 3510-22-P

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[GRAPHIC] [TIFF OMITTED] TN02FE22.000

BILLING CODE 3510-22-C

Dates and Duration

    In-water construction is scheduled to begin on March 1, 2022, upon 
expiration of the current Phase I IHA (86 FR 23938; May 5, 2021). ADOT 
anticipates that construction would occur during daylight hours only 
with in-water construction occurring 6 days per week. ADOT anticipates 
that the project would require approximately 91 days of pile 
installation and removal

[[Page 5983]]

over the course of 7 or 8 months. Although it is anticipated that the 
project would be completed sooner, ADOT requests that the IHA be valid 
for a full year, from March 1, 2022 to February 28, 2023, to 
accommodate scheduling unknowns or delays.
    ADOT plans to implement the Essential Fish Habitat (EFH) 
Conservation Recommendations developed by NMFS. No in-water work would 
occur between March 1 and June 15 for three project components: The 
Revilla New Ferry Berth and Upland Improvements, Gravina Airport Ferry 
Layup Facility, and Revilla Refurbish Existing Ferry Berth Facility.

Specific Geographic Region

    The proposed construction project is located in Ketchikan, Alaska 
(Figure 1). Improvements to the Gravina Airport Ferry Layup Facility 
construction would occur in the same location as the existing layup 
dock facility. The new Gravina Freight Facility would be constructed in 
the same location as the existing barge offload facility. The New 
Gravina Island Shuttle Ferry Berth construction would occur slightly 
North of the Airport Ferry Layup Facility. Improvements and 
construction on Revilla Island would occur approximately 4 kilometers 
(km; 2.5 miles (mi)) north of downtown Ketchikan. The new Revilla 
Island Airport Shuttle Ferry Berth would be constructed immediately 
adjacent to the existing Revilla Island Ferry Berth.
    Tongass Narrows is an approximately 13-mile-long, north-south-
oriented marine channel situated between Revilla Island to the east and 
Gravina Island to the west. In the vicinity of the proposed project, 
Tongass Narrows is as little as 300 meters (m; 984 feet; ft) wide. 
Tongass Narrows is generally characterized by strong tidal currents and 
by steep bedrock or coarse gravel-cobble-boulder shoreline. Lower 
intertidal and shallow subtidal areas are often sandy or mixed gravel, 
sand, and shell, with varied amounts of silt. At other areas, however, 
such as at rocky points and along the northwestern shore of Pennock 
Island (which is located in the south end of Tongass Narrows, between 
Gravina and Revilla Islands), bedrock slopes steeply to subtidal 
depths. Subtidal habitats are a mix of bedrock outcrops or ledges, 
boulder-cobble slopes, and, where lower slopes permit, sandy gravel 
bottoms, often mixed with significant amounts of shell debris, similar 
to intertidal habitats.
    Several small natural coves and areas protected by constructed 
breakwaters provide wave and current protection for marine habitats 
with sand or gravel bottoms with some areas of eelgrass (Zostera 
marina) beds. Extensive areas of riprap bank protection and fill occur 
along the northeastern shoreline of the City of Ketchikan. Construction 
of numerous buildings and docks on pilings over the intertidal and 
shallow subtidal zone has significantly modified the shorelines in 
these areas. Shoreline protection activities have similarly modified 
approximately 1 mile of the shoreline of Gravina Island in the vicinity 
of the airport and airport ferry terminal.
    Water depths reach approximately 49 m (160 ft) in the middle of the 
Tongass Narrows between the airport and town, but generally do not 
exceed 18 m (60 ft) where piles would be installed. The channel bottom 
slopes at about 2:1 (horizontal: vertical) from opposite shores. 
Geological conditions in the vicinity of the project were recently 
evaluated (CH2M 2018). The substrate consists of approximately 18 to 23 
m (60 to 75 ft) of very loose to very dense granular deltaic or 
alluvial sand and gravel. At approximately 18 to 23 m (60 to 75 ft) 
below the mudline, the substrate transitions to phyllite bedrock (CH2M 
2018). Pile installation would occur in waters ranging in depth from 
less than 1 m (3.3 ft) nearshore to approximately 20 m (66 ft), 
depending on the structure and location.
    Ongoing vessel activities throughout Tongass Narrows, land-based 
industrial and commercial activities, and regular aircraft operations 
result in elevated in-air and underwater sound conditions in the 
project area that increase with proximity to the proposed project 
component sites. Sound levels likely vary seasonally, with elevated 
levels during summer when the tourism and fishing industries are at 
their peaks.

Detailed Description of Specific Activity

    Planned construction includes the installation and continued 
construction of new ferry facilities and the renovation of existing 
structures. As stated above, the four proposed construction components 
include: The Gravina Airport Ferry Layup Facility, the Gravina Freight 
Facility, the Revilla New Ferry Berth and Upland Improvements, and the 
New Gravina Island Shuttle Ferry Berth and Related Terminal 
Improvements. ADOT anticipates that work may occur at multiple sites 
concurrently, and that two hammers or DTH equipment could be used 
concurrently (discussed further in the Estimated Take section).
Gravina Airport Ferry Layup Facility
    The new ferry layup dock and transfer bridge would support layup 
and maintenance of the airport ferry system. The current layup dock at 
the Gravina Airport Ferry Layup Facility is in disrepair and needs to 
be replaced. ADOT would remove the existing 265-ft (80.1-m)-long 
floating dock, mooring structures, and transfer bridge and construct a 
new 250-ft by 85-ft (76.2 m by 25.9 m) concrete or steel floating dock 
in its place. The floating dock would be restrained by two side-
restraint float dolphins and three corner/mid-restraint float dolphins. 
A new 20-ft by 140-ft (6.1 m by 42.6 m) steel transfer bridge would 
provide access to the floating dock. It would be necessary to remove, 
relocate, and replenish the existing rock slope, demolish the existing 
concrete abutment, and construct a new pile-supported bridge abutment. 
The Gravina Airport Ferry Layup Facility construction and Gravina 
Freight Facility construction is anticipated to require a total of 47 
days of in-water pile installation and removal.
Gravina Freight Facility
    The new Gravina Freight Facility, located approximately 100 m from 
the Gravina Airport Ferry Layup Facility (Figure 1), would be 
constructed in the same location as the existing barge offload 
facility. This facility would provide improved access to Gravina Island 
for highway loads that cannot be accommodated by the shuttle ferry. The 
existing ramp would be widened and re-graded both above and below the 
high tide line. A new concrete plank or asphalt pavement ramp would be 
constructed in its place. Five breasting dolphins and one mooring 
dolphin would be constructed to support barge docking and would include 
pedestrian walkways for access by personnel. In addition, two new pile-
supported mooring structures would be constructed above the high tide 
line. As stated above, the Gravina Airport Ferry Layup Facility 
construction and Gravina Freight Facility construction is anticipated 
to require a total of 47 days of in-water pile installation and 
removal.
Revilla New Ferry Berth and Upland Improvements
    The new Revilla Island airport shuttle ferry berth is the only 
project component that would occur on Revilla Island, and is currently 
under construction immediately adjacent to the existing Revilla Island 
Ferry Berth (Figure 1). The new ferry berth consists of a 7,400 square 
ft (ft\2\; 687.4 m\2\) pile-supported approach trestle at the shore 
side of the ferry terminal and a 1,500 ft\2\ (139.4 m) pile-supported 
approach

[[Page 5984]]

trestle extension located landside and north of the new approach 
trestle. A 25-ft by 142-ft (7.6 m by 43.2 m) steel transfer bridge with 
vehicle traffic lane and separated pedestrian walkway extends from the 
trestle to a new 2,200 ft\2\ (204.3 m\2\) steel float and apron. The 
steel float is supported by three guide pile dolphins. A bulkhead 
retaining wall is being constructed at the transition from uplands to 
the approach trestle. Two new stern berth dolphins with fixed hanging 
fenders and three new floating fender dolphins are being constructed to 
moor vessels. The new apron would be supported by three new guide pile 
dolphins. Water depths at the dolphins reach approximately 60 ft (18.2 
m).
    While construction on the Revilla New Ferry Berth is already 
underway, ADOT anticipates that it would not be complete before ADOT's 
current IHA (86 FR 23938; May 5, 2021) expires. Therefore, ADOT has 
requested take associated with the portion of the project that it 
anticipates may remain, which consists of installation of up to five 
tension anchors.
    Upland improvements associated with the Revilla New Ferry Berth 
include reconstruction of terminal facilities, installation of 
utilities, and construction of improvements to existing staging/parking 
areas. Upland improvements are not anticipated to harass marine 
mammals, and therefore, are not discussed further in this document.
Gravina Island Shuttle Ferry Berth and Related Terminal Improvements
    The new Gravina Island Airport Shuttle Ferry Berth is currently 
under construction (86 FR 23938; May 5, 2021) immediately adjacent to 
the existing Gravina Island Ferry Berth (Figure 1). The new facility 
consists of an approximately 7,000 ft\2\ (650.3 m\2\) pile-supported 
approach trestle at the shore side of the ferry terminal. A 25-ft by 
142-ft (7.6 m by 43.2 m) steel transfer bridge with vehicle traffic 
lane and separated pedestrian walkway leads to a new 2,200 ft\2\ (204.3 
m\2\) steel float and apron. The steel float is supported by three new 
guide pile dolphins. Ferry berthing is supported by two new stern berth 
dolphins and three new floating fender dolphins. To support the new 
facility, a new bulkhead retaining wall is being constructed between 
the existing ferry berth and the new approach trestle. A new fill slope 
measuring approximately 21,200 ft\2\ (1,969.5 m\2\) is being 
constructed west of the approach trestle. Upland improvements include 
widening of the ferry approach road, retrofits to the existing 
pedestrian walkway, installation of utilities, and construction of a 
new employee access walkway. Due to unforeseen construction delays 
encountered during the Phase 1 IHA construction period, ADOT 
anticipates that construction on the Gravina Island Shuttle Ferry Berth 
would not be completed before the expiration of the current IHA (86 FR 
23938; May 5, 2021). Therefore, ADOT has requested take associated with 
the portion of the project that it anticipates may remain, which 
consists of up to 35 piles (both plumb and battered), 17-21 rock 
sockets, 28 tension anchors, and up to 4 micropile anchors (Table 1).
    Across the four project sites, three methods of pile installation 
are anticipated. These include vibratory and impact hammers, use of DTH 
systems to make holes for rock sockets and tension and micropile 
anchors at some locations (Figure 1-3 of ADOT's IHA Application). 
Installation of steel piles through the sediment layer would be 
accomplished using vibratory or impact methods. Depending on the 
location, the pile would be advanced to refusal at bedrock. Where 
sediments are deep and rock socketing or anchoring (described below) is 
not required, the final approximately 10 ft (3 m) of driving would be 
conducted using an impact hammer so that the structural capacity of the 
pile embedment can be verified or proofed. Proofing is expected to 
require approximately 50 strikes over 15 minutes. Where sediments are 
shallow, an impact hammer would be used to seat the piles into 
competent bedrock before a DTH system is used to create holes for the 
rock sockets and/or tension anchors. The pile installation methods used 
would depend on sediment depth and conditions at each pile location.
    Rock sockets are holes made in the bedrock where overlying 
sediments are too shallow to adequately secure the bottom portion of a 
pile using other methods. Rock sockets are constructed utilizing a DTH 
device which uses both rotary and percussion-type drill action. These 
devices consist of a drill bit that drills through the bedrock using 
both rotary and pulse impact mechanisms. This breaks up the rock to 
allow removal of the fragments, creating a hole that allows for 
insertion of the pile. The socket holes are just large enough for the 
pile to fit down in to provide lateral strength for the pile. The pile 
is usually advanced at the same time that drilling occurs (the bit has 
a flexible tip that can be retracted and pulled back up through the 
center of a pile). Rock socket holes would be up to 15 ft (4.6 m) into 
the bedrock. Drill cuttings are expelled from the top of the pile using 
compressed air and/or other fluids. It is estimated that use of DTH for 
rock sockets into the bedrock would take approximately 4-8 hours per 
pile. Some piles would be seated in rock sockets as well as anchored 
with tension anchors.
    Tension anchors are comprised of a threaded steel rod grouted into 
the bedrock strata at a specified depth below the pile tip. The rod is 
tested and anchored to the top of the pile to resist uplift forces in 
the associated structure. Tension anchors are installed within piles 
that are DTH drilled or hammered into the bedrock below the elevation 
of the pile tip, after the pile has been driven through the sediment 
layer to refusal. A 6- or 8-inch-diameter steel pipe casing is inserted 
inside the larger-diameter production pile. A DTH hammer and bit is 
inserted into the casing, and a 6- to 8-inch-diameter hole is made into 
bedrock. The typical depth of the hole varies, but 20-30 ft (6.1-9.1 m) 
is common to meet engineering needs. Rock fragments would be removed 
through the top of the casing with compressed air. A steel rebar rod is 
then grouted into the drilled hole and affixed to the top of the pile.
    Micropiles have a casing diameter of approximately 3 to 10 in. A 
DTH hammer device is used to create a hole in a manner identical to the 
rock sockets as described above. The micropile casing is inserted to 
depth and a steel reinforcement bar is inserted in the casing, and then 
grout is pumped into the casing. The construction of the Gravina Island 
Shuttle Ferry Berth could potentially utilize up to four micropiles. 
Because both tension anchors and micropiles require drilling an 8-inch-
diameter hole, they are discussed together throughout this document.
    Vibratory methods would also be used to remove temporary steel pipe 
piles. These proposed activities and the noise they produce have the 
potential to take marine mammals, by Level A harassment and Level B 
harassment of marine mammals.
    Each of the project components would include installation of steel 
pipe piles that are 20, 24, or 30 inches in diameter (Table 1). 
Temporary piles would be installed and removed with a vibratory hammer. 
Some permanent piles would be battered (i.e., installed at an angle). 
Approximately 50 impact strikes would be required for proofing each 
permanent pile, requiring approximately 15 minutes of active impact 
hammering per pile.
    The estimated average installation rate for the project is one to 
one and a half permanent or two temporary pipe piles per day (Table 1). 
On some days,

[[Page 5985]]

more or fewer piles or partial piles may be installed. It would likely 
not be possible to install an individual permanent pile to refusal with 
a vibratory hammer, use DTH methods for the rock socket, impact proof, 
and install the tension anchor on the same day. The construction crew 
may use a single installation method for multiple piles on a single day 
or find other efficiencies to increase production; the anticipated 
ranges of possible values are provided in Table 1. The estimated 
removal rate for temporary piles is two steel pipe piles per day. On 
some days, more or fewer piles may be removed. It is estimated that the 
40 temporary piles would be removed in 36 days.
    In sum, approximately 91 days of pile installation and removal are 
anticipated (Table 1), and of the 102 piles which ADOT anticipates it 
will install, 40 of them will be installed and removed (for a total of 
142 pile installations and removals).
    Above-water work would consist of the installation of a concrete 
float, a transfer bridge and transition ramp, dock-mounted fenders, and 
utility lines. A utility and storage building would be constructed on 
top of the concrete float. No in-water noise is anticipated in 
association with above-water and upland construction activities, and no 
associated take of marine mammals is anticipated from the noise or 
visual disturbance. Therefore, above-water and upland construction 
activities are not discussed further in this document.
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TN02FE22.001


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BILLING CODE 3510-22-C
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this specified activity, and summarizes 
information related to the population or stock, including regulatory 
status under the MMPA and Endangered Species Act (ESA) and potential 
biological removal (PBR), where known. For taxonomy, we follow 
Committee on Taxonomy (2021). 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. 2021). All values presented 
in Table 2 are the most recent available at the time of publication and 
are available in the draft 2021 SARs (Muto et al. 2021; available 
online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                            Table 2--Marine Mammal Species or Stocks for Which Take Is Expected and Proposed To Be Authorized
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                         Stock abundance
                                                                                    ESA/MMPA status;    Nbest, (CV; Nmin;                      Annual  M/
            Common name                  Scientific name           MMPA stock        strategic (Y/N)  most recent abundance         PBR          SI \3\
                                                                                           \1\             survey) \2\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
    Humpback whale.................  Megaptera novaeangliae  Central North Pacific  E, D, Y           10,103 (0.3; 7,890;    83..............         26
                                                                                                       2006).
    Minke whale....................  Balaenoptera            Alaska...............  -, N              N.A.(See SAR; N.A.;    UND.............          0
                                      acutorostrata.                                                   see SAR).
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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              349 (N.A, 349; 2018).  3.5.............        0.4
                                                             Northern Resident....  -, N              302 (N.A.; 302; 2018.  2.2.............        0.2
    Pacific white-sided dolphin....  Lagenorhynchus          North Pacific........  -,-; N            26,880 (N.A.; N.A.;    UND.............          0
                                      obliquidens.                                                     1990).
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                                                                   Family Phocoenidae
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Harbor porpoise................  Phocoena phocoena.....  Southeast Alaska.....  -, Y              See SAR (see SAR; see  See SAR.........         34
                                                                                                       SAR; 2012).
    Dall's porpoise................  Phocoenoides dalli....  Alaska...............  -, N              See SAR (see SAR; see  See SAR.........         37
                                                                                                       SAR; 2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
 Family Otariidae (eared seals and
 sea lions):
    Steller sea lion...............  Eumetopias jubatus....  Eastern U.S..........  -,-, N            43,201 (see SAR;       2,592...........        112
                                                                                                       43,201; 2017).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocidae (earless seals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Harbor seal....................  Phoca vitulina          Clarence Strait......  -, N              27,659 (See SAE;       746.............         40
                                      richardii.                                                       24,854; 2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 (M/SI) 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.

    All species that could potentially occur in the proposed survey 
areas are included in Table 3-1 of the IHA application. However, the 
spatial occurrence of gray whale and fin whale is such that take is not 
expected to

[[Page 5987]]

occur, and they are not discussed further beyond the explanation 
provided here. Gray whales have not been reported by any local experts 
or recorded in monitoring reports and it would be extremely unlikely 
for a gray whale to enter Tongass Narrows or the small portions of 
Revillagigedo Channel this project would impact. Similarly for fin 
whale, sightings have not been reported and it would be unlikely for a 
fin whale to enter the project area as they are generally associated 
with deeper, more offshore waters. The remaining eight species (with 10 
managed stocks) in Table 2 temporally and spatially co-occur with the 
activity to the degree that take is reasonably likely to occur, and we 
have proposed authorizing it.

Humpback Whale

    Humpback whales are found throughout Southeast Alaska in a variety 
of marine environments, including open-ocean, near-shore waters, and 
areas with strong tidal currents (Dahlheim et al. 2009). Most humpback 
whales are migratory and spend winters in the breeding grounds off 
either Hawaii or Mexico. Humpback whales generally arrive in Southeast 
Alaska in March and return to their wintering grounds in November. Some 
humpback whales depart late or arrive early to feeding grounds, and 
therefore the species occurs in Southeast Alaska year-round (Straley 
1990; Straley et al. 2018). Current threats to humpback whales include 
vessel strikes, spills, climate change, and commercial fishing 
operations (Muto et al. 2021).
    Humpback whales worldwide were designated as ``endangered'' under 
the Endangered Species Conservation Act in 1970, and were listed under 
the ESA at its inception in 1973. However, on September 8, 2016, NMFS 
published a final decision that changed the status of humpback whales 
under the ESA (81 FR 62259), effective October 11, 2016. The decision 
recognized the existence of 14 DPSs based on distinct breeding areas in 
tropical and temperate waters. Five of the 14 DPSs were classified 
under the ESA (4 endangered and 1 threatened), while the other 9 DPSs 
were delisted. Humpback whales found in the project area are 
predominantly members of the Hawaii DPS, which is not listed under the 
ESA. However, based on a comprehensive photo-identification study, 
members of the Mexico DPS, which is listed as threatened, are known to 
occur in Southeast Alaska. Members of different DPSs are known to 
intermix on feeding grounds; therefore, all waters off the coast of 
Alaska should be considered to have ESA-listed humpback whales. 
Approximately 2 percent of all humpback whales in Southeast Alaska and 
northern British Columbia are members of the Mexico DPS, while all 
others are members of the Hawaii DPS (Wade et al. 2021).
    The DPSs of humpback whales that were identified through the ESA 
listing process do not necessarily equate to the existing MMPA stocks. 
The stock delineations of humpback whales under the MMPA are currently 
under review. Until this review is complete, NMFS considers humpback 
whales in Southeast Alaska to be part of the Central North Pacific 
stock, with a status of endangered under the ESA and designations of 
strategic and depleted under the MMPA (Muto et al. 2021).
    Southeast Alaska is considered a biologically important area for 
feeding humpback whales between March and May (Ellison et al. 2012), 
though not currently designated as critical habitat (86 FR 21082; April 
21, 2021). Most humpback whales migrate to other regions during the 
winter to breed, but rare events of over-wintering humpbacks have been 
noted, and may be attributable to staggered migration (Straley, 1990; 
Straley et al. 2018). It is thought that those humpbacks that remain in 
Southeast Alaska do so in response to the availability of winter 
schools of fish prey, which primarily includes overwintering herring 
(Straley et al. 2018). In Alaska, humpback whales filter feed on tiny 
crustaceans, plankton, and small fish such as walleye pollock, Pacific 
sand lance, herring, eulachon, and capelin (Witteveen et al. 2012). It 
is common to observe groups of humpback whales cooperatively bubble 
feeding. Group sizes in Southeast Alaska generally range from one to 
four individuals (Dahlheim et al. 2009).
    No systematic studies have documented humpback whale abundance near 
Ketchikan. Anecdotal information (See Section 4 of IHA Application) 
suggests that this species is present in low numbers year-round in 
Tongass Narrows, with the highest abundance during summer and fall. 
Anecdotal reports suggest that humpback whales are seen only once or 
twice per month, while more recently it has been suggested that the 
occurrence is more regular, such as once per week on average, and more 
seasonal. Humpbacks observed in Tongass Narrows are generally alone or 
in groups of one to three individuals. Most humpback whales depart 
Alaska for their breeding grounds in October and November, and return 
in March and April. In August 2017, a group of six individuals was 
observed passing through Tongass Narrows several times per day, for 
several days in a row. Local residents reported that such high 
abundance is common in August and September. NMFS reported that in 2018 
airport ferry personnel observed a lone humpback whale in the area 
every few days for several months and a group of two humpback whales 
every other week (Muto et al. 2019).
    In the Biological Opinion for this project, NMFS assumed the 
occurrence of humpback whales in the project area to be one two 
individuals twice per week, year-round. The assumption was based on 
differences in abundance throughout the year, recent observations of 
larger groups of whales present during summer, and a higher than 
average frequency of occurrence in recent months.
    The City of Ketchikan (COK) Rock Pinnacle project, which was 
located approximately 4 km southeast of the proposed project site, 
reported one humpback whale sighting of one individual during the 
project (December 2019 through January 2020) (Sitkiewicz 2020). During 
the Ward Cove Cruise Ship Dock Construction, located approximately 5 km 
northwest of the proposed project site, protected species observers 
(PSOs) observed 28 sightings of humpbacks on eighteen days of in water 
work that occurred between February and September 2020, with at least 
one humpback being recorded every month. A total of 42 individuals were 
recorded and group sizes ranged from solo whales to pods of up to six 
(Power Systems & Supplies of Alaska 2020). Humpbacks were recorded in 
each month of construction, with the most individuals (10) being 
recorded in May, 2020.
    Humpback whales were sighted on 17 days out of 88 days of 
monitoring in Tongass Narrows in 2020 and 2021 (DOT&PF 2020, 2021a, 
2021b, 2021c, 2021d). There were no sightings in January or February, 
but humpback whales were observed each month from October to December 
2020 and May to June 2021 (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). 
There was only 1 day in June in which humpback whales were observed, 
but on that day there were four groups of whales--three pairs and one 
group of four (DOT&PF 2021d). In other months, humpback whale sightings 
were mostly individual animals and occasionally pairs. During November 
2020, a single known individual (by fluke pattern) was observed 
repeatedly, accounting for 14 of the 26 sighting events that month 
(DOT&PF 2020). During monitoring, humpback whales were observed on 
average once a week.

[[Page 5988]]

Minke Whale

    Minke whales are found throughout the northern hemisphere in polar, 
temperate, and tropical waters. The population status of minke whales 
is considered stable throughout most of their range. Historically, 
commercial whaling reduced the population size of this species, but 
given their small size, they were never a primary target of whaling and 
did not experience the severe population declines as did larger 
cetaceans.
    The International Whaling Commission has identified a less 
concentrated stock throughout the eastern Pacific. NOAA further splits 
this stock between Alaska whales and resident whales of California, 
Oregon, and Washington (Muto et al., 2021). Minke whales are found in 
all Alaska waters. There are no population estimates for minke whales 
in Alaska. Surveys in Southeast Alaska have consistently identified 
individuals throughout inland waters in low numbers (Dahlheim et al. 
2009).
    Minke whales in Southeast Alaska are part of the Alaska stock (Muto 
et al. 2021). Dedicated surveys for cetaceans in Southeast Alaska found 
that minke whales were scattered throughout inland waters from Glacier 
Bay and Icy Strait to Clarence Strait, with small concentrations near 
the entrance of Glacier Bay (Dahlheim et al. 2009). All sightings were 
of single minke whales, except for a single sighting of multiple minke 
whales. Surveys took place in spring, summer, and fall, and minke 
whales were present in low numbers in all seasons and years. No 
information appears to be available on the winter occurrence of minke 
whales in Southeast Alaska.
    In Alaska, the minke whale diet consists primarily of euphausiids 
and walleye pollock. Minke whales are generally found in shallow, 
coastal waters within 200 m of shore (Zerbini et al. 2006) and are 
almost always solitary or in small groups of 2 to 3. In Alaska, 
seasonal movements are associated with feeding areas that are generally 
located at the edge of the pack ice (NMFS 2014).
    There are no known occurrences of minke whales within the project 
area. Since their ranges extend into the project area and they have 
been observed in southeast Alaska, including in Clarence Strait 
(Dahlheim et al., 2009), it is possible the species could occur near 
the project area. During the surveys by Dalheim et al. (2009), all but 
one encounter was with a single whale and, although infrequent, minke 
whales were observed during all seasons surveyed (spring, summer and 
fall). No minke whales where reported during the COK Rock Pinnacle 
Blasting Project (Sitkiewicz 2020). During marine mammal monitoring of 
Tongass Narrows in 2020 and 2021, there were no minke whales observed 
on 88 days of observations across 7 months (October 2020-February 2021; 
May-June 2021) (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). Future 
observations of minke whale in the project area are expected to be 
rare.

Killer Whale

    Killer whales have been observed in all the world's oceans, but the 
highest densities occur in colder and more productive waters found at 
high latitudes (NMFS 2016). Killer whales occur along the entire Alaska 
coast, in British Columbia and Washington inland waterways, and along 
the outer coasts of Washington, Oregon, and California (NMFS 2016).
    Based on data regarding association patterns, acoustics, movements, 
and genetic differences, eight killer whale stocks are now recognized 
within the Pacific U.S. Exclusive Economic Zone. This proposed IHA 
considers only the Eastern North Pacific Alaska Resident stock (Alaska 
Resident stock), Eastern North Pacific Northern Resident stock 
(Northern Resident stock), and West Coast Transient stock, because all 
other stocks occur outside the geographic area under consideration 
(Muto et al., 2021).
    There are three distinct ecotypes, or forms, of killer whales 
recognized: Resident, Transient, and Offshore. The three ecotypes 
differ morphologically, ecologically, behaviorally, and genetically. 
Surveys between 1991 and 2007 encountered resident killer whales during 
all seasons throughout Southeast Alaska. Both residents and transients 
were common in a variety of habitats and all major waterways, including 
protected bays and inlets. There does not appear to be strong seasonal 
variation in abundance or distribution of killer whales, but there was 
substantial variability between years during this study (Dahlheim et 
al., 2009). Spatial distribution has been shown to vary among the 
different ecotypes, with resident and, to a lesser extent, transient 
killer whales more commonly observed along the continental shelf, and 
offshore killer whales more commonly observed in pelagic waters (Rice 
et al., 2021).
    No systematic studies of killer whales have been conducted in or 
around Tongass Narrows. Killer whales have been observed in Tongass 
Narrows year-round and are most common during the summer Chinook salmon 
run (May-July). During the Chinook salmon run, Ketchikan residents have 
reported pods of 20-30 whales and during the 2016/2017 winter a pod of 
5 whales was observed in Tongass Narrows (84 FR 36891; July 30, 2019). 
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 (Frietag 2017). Anecdotal 
reports suggest that large pods of killer whales (as many as 80 
individuals, but generally between 25 and 40 individuals) are not 
uncommon in May, June, and July when the king salmon are running. 
During the rest of the year, killer whales occur irregularly in pods of 
6 to 12 or more individuals. Large pods would be indicative of the 
Alaska resident population, which travels and hunts in large social 
groups.
    Transient killer whales are often found in long-term stable social 
units (pods) of 1 to 16 whales. Average pod sizes in Southeast Alaska 
were 6.0 in spring, 5.0 in summer, and 3.9 in fall. Pod sizes of 
transient whales are generally smaller than those of resident social 
groups. Resident killer whales occur in larger pods, ranging from 7 to 
70 whales that are seen in association with one another more than 50 
percent of the time (Dahlheim et al., 2009; NMFS 2016b). In Southeast 
Alaska, resident killer whale mean pod size was approximately 21.5 in 
spring, 32.3 in summer, and 19.3 in fall (Dahlheim et al., 2009).
    Although killer whales may occur in large numbers, they generally 
form large pods and would incur fewer work stoppages than their numbers 
suggest. Killer whales tend to transit through Tongass Narrows, and do 
not linger in the project area.
    Marine mammal observations in Tongass Narrows during 2020 and 2021 
support an estimate of approximately one group of killer whales a month 
in the project area. During 7 months of monitoring (October 2020-
February 2021; May-June 2021), there were five killer whale sightings 
in 4 months (November, February, May, June) totaling 22 animals and 
sightings occurred on 5 out of 88 days of monitoring (DOT&PF 2020, 
2021a, 2021b, 2021c, 2021d). Pod sizes ranged from two to eight animals 
(DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). During the COK's monitoring 
for the Rock Pinnacle Removal project in December 2019 and January 
2020, no killer whales were observed (Sitkiewicz 2020). Over 8 months 
of monitoring at the Ward Cove Cruise Ship Dock in 2020, killer whales 
were only observed on two days in March (Power Systems

[[Page 5989]]

and Supplies of Alaska, 2020). These observations included a sighting 
of one pod of two killer whales and a second pod of five individuals 
travelling through the project area.

Pacific White-Sided Dolphin

    Pacific white-sided dolphins are a pelagic species inhabiting 
temperate waters of the North Pacific Ocean and along the coasts of 
California, Oregon, Washington, and Alaska (Muto et al., 2021). Despite 
their distribution mostly in deep, offshore waters, they may also be 
found over the continental shelf and near shore waters, including 
inland waters of Southeast Alaska (Ferrero and Walker 1996). The North 
Pacific stock is found within the project area. The Pacific white-sided 
dolphin is distributed throughout the temperate North Pacific Ocean, 
north of Baja California to Alaska's southern coastline and Aleutian 
Islands. The North Pacific Stock ranges from Canada into Alaska (Muto 
et al., 2021).
    Pacific white-sided dolphins prey on squid and small schooling fish 
such as capelin, sardines, and herring (Morton 2006). They are known to 
work in groups to herd schools of fish and can dive underwater for up 
to 6 minutes to feed (Morton 2006). Group sizes have been reported to 
range from 40 to over 1,000 animals, but groups of between 10 and 100 
individuals (Stacey and Baird 1991) occur most commonly. Seasonal 
movements of Pacific white-sided dolphins are not well understood, but 
there is evidence of both north-south seasonal movement (Leatherwood et 
al. 1984) and inshore-offshore seasonal movement (Stacey and Baird 
1991).
    Scientific studies and data are lacking relative to the presence or 
abundance of Pacific white-sided dolphins in or near Tongass Narrows. 
Although they generally prefer deeper and more-offshore waters, 
anecdotal reports suggest that Pacific white-sided dolphins have 
previously been observed in Tongass Narrows, although they have not 
been observed entering Tongass Narrows or nearby inter-island waterways 
in 15-20 years.
    Pacific white-sided dolphins are rare in the inside passageways of 
Southeast Alaska. Most observations occur off the outer coast or in 
inland waterways near entrances to the open ocean. According to Muto et 
al. (2018), aerial surveys in 1997 sighted one group of 164 Pacific 
white-sided dolphins in Dixon entrance to the south of Tongass Narrows. 
Surveys in April and May from 1991 to 1993 identified Pacific white-
sided dolphins in Revillagigedo Channel, Behm Canal, and Clarence 
Strait (Dahlheim and Towell 1994). These areas are contiguous with the 
open ocean waters of Dixon Entrance. 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 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. This observational data, combined with anecdotal 
information, indicates there is a rare, however, slight potential for 
Pacific white-sided dolphins to occur in the project area.
    During marine mammal monitoring of Tongass Narrows in 2020 and 
2021, no Pacific white-sided dolphins were observed on 88 days of 
observations across 7 months (October 2020-February 2021; May-June 
2021), which supports the anecdotal evidence that sightings of this 
species are rare (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). There were 
also no sightings of Pacific white-sided dolphins during the COK Rock 
Pinnacle Blasting Project during monitoring surveys conducted in 
December 2019 and January 2020 (Sitkiewicz 2020) or during monitoring 
surveys conducted between February and September 2020 as part of the 
Ward Cove Cruise Ship Dock (Power Systems and Supplies of Alaska, 
2020).

Harbor Porpoise

    In the eastern North Pacific Ocean, the harbor porpoise ranges from 
Point Barrow, along the Alaska coast, and down the west coast of North 
America to Point Conception, California. In Alaska, harbor porpoises 
are currently divided into three stocks, based primarily on geography: 
The Bering Sea stock, the Southeast Alaska stock, and the Gulf of 
Alaska stock. The Southeast Alaska stock ranges from Cape Suckling to 
the Canadian border (Muto et al. 2021). Harbor porpoises frequent 
primarily coastal waters in Southeast Alaska (Dahlheim et al. 2009) and 
occur most frequently in waters less than 100 m (328 ft) deep (Hobbs 
and Waite 2010; Dahlheim et al. 2015).
    Abundance data for harbor porpoises in Southeast Alaska were 
collected during 18 seasonal surveys spanning 22 years, from 1991 to 
2012 (Dahlheim et al. 2015). The project area and Tongass Narrows fall 
within the Clarence Strait to Ketchikan region, as identified by this 
study for the survey effort. Harbor porpoise densities in this region 
in summer were low, ranging from 0.01 to 0.02 harbor porpoises/km\2\.
    Studies of harbor porpoises reported no evidence of seasonal 
changes in distribution for the inland waters of Southeast Alaska 
(Dahlheim et al. 2009). Their small overall size, lack of a visible 
blow, low dorsal fins and overall low profile, and short surfacing time 
make them difficult to observe (Dahlheim et al. 2015), likely reducing 
identification and reporting of this species, and these estimates 
therefore may be low.
    Calving occurs from May to August; however, this can vary by 
region. Harbor porpoises are often found traveling alone, or in small 
groups less than 10 individuals (Schmale 2008). According to aerial 
surveys of harbor porpoise abundance in Alaska conducted in 1991-1993, 
mean group size in Southeast Alaska was calculated to be 1.2 animals 
(Dahlheim et al. 2000).
    Anecdotal reports (see Section 3 of the IHA Application) specific 
to Tongass Narrows indicate that harbor porpoises are rarely observed 
in the project area, and actual sightings are less common than those 
suggested by Dahlheim et al. (2015). Harbor porpoises prefer shallower 
waters (Dahlheim et al. 2015) and generally are not attracted to areas 
with elevated levels of vessel activity and noise such as Tongass 
Narrows. Harbor porpoises are expected to be present in the project 
area only a few times per year. Freitag (2017 as cited in 83 FR 22009; 
May 11, 2018) observed harbor porpoises in Tongass Narrows zero to one 
time per month and NMFS (83 FR 22009; May 11, 2018) has estimated that 
one group of harbor porpoises would enter Tongass Narrows each month.
    Harbor porpoises were sighted on 3 days of in-water work during 
monitoring associated with the Ward Cove Cruise Ship Dock, with three 
sightings of 15 individuals sighted in March and April, 2020 (Power 
Systems and Supplies of Alaska, 2020). Solo individuals and pods of up 
to 10 were identified as swimming and travelling 2,500 m to 2,800 m 
from in-water work. During marine mammal monitoring of Tongass Narrows 
in 2020 and 2021, no harbor porpoises were observed on 88 days of 
observations across 7 months (October 2020-February 2021; May-June 
2021), which supports the anecdotal evidence that harbor porpoise 
sightings are rare (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). Marine 
mammal

[[Page 5990]]

monitoring associated with the COK Rock Pinnacle Removal project also 
did not observe any harbor porpoise during surveys conducted in 
December 2019 and January 2020 (Sitkiewicz 2020).

Dall's Porpoise

    Dall's porpoises are found throughout the North Pacific, from 
southern Japan to southern California north to the Bering Sea. Dall's 
porpoises are not listed as endangered or threatened under the ESA. All 
Dall's porpoises in Alaska are members of the Alaska stock, and those 
off California, Oregon, and Washington are part of a separate stock. 
This species can be found in offshore, inshore, and nearshore habitat, 
but prefer waters more than 600 ft (180 m) deep (Jefferson 2009).
    No systematic studies of Dall's porpoise abundance or distribution 
have occurred in Tongass Narrows; however, surveys for cetaceans 
throughout Southeast Alaska were conducted between 1991 and 2007 
(Dahlheim et al. 2009). The species is generally found in waters in 
excess of 600 ft (183 m) deep (Dahlheim et al. 2009, Jefferson 2009), 
which do not occur in Tongass Narrows. 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. Anecdotal 
reports suggest that Dall's porpoises are found northwest of Ketchikan 
near the Guard Islands, where waters are deeper, as well as in deeper 
waters to the southeast of Tongass Narrows. Should Dall's porpoises 
occur in the project area, they would likely be present in March or 
April, given past observations in the region. Despite generalized water 
depth preferences, Dall's porpoises may occur in shallower waters. This 
species has a tendency to bow-ride with vessels and may occur in the 
project area incidentally a few times per year.
    The mean group size in Southeast Alaska is estimated at 
approximately three individuals (Dahlheim et al. 2009; Jefferson 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, 83 FR 37473; August 1, 2018).
    Dall's porpoises were positively identified on 2 days of in-water 
work during monitoring associated with the Ward Cove Cruise Ship Dock 
(Power Systems and Supplies of Alaska, 2020). A pod of three and a pod 
of five were recorded travelling at least 3,000 m from the construction 
site in April and May, respectively. During marine mammal monitoring of 
Tongass Narrows in 2020 and 2021, there were sightings of Dall's 
porpoises on 2 out of 88 days of observations across 7 months (October 
2020-February 2021; May-June 2021)--once in November 2020 and once in 
February 2021. The pod sighted in November contained six animals; the 
pod observed in February had 10. Based on this recent data, there is no 
known pattern to their attendance in the project area, but they do 
occur rarely (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d).

Steller Sea Lion

    Steller sea lions were listed as threatened range-wide under the 
ESA on November 26, 1990 (55 FR 49204). Steller sea lions were 
subsequently partitioned into the western and eastern DPSs (and MMPA 
stocks) in 1997 (62 FR 24345; May 5, 1997). The eastern DPS remained 
classified as threatened until it was delisted in November 2013. The 
current minimum abundance estimate for the eastern DPS of Steller sea 
lions is 43,201 individuals (Muto et al. 2021). The western DPS (those 
individuals west of 144[deg] W longitude or Cape Suckling, Alaska) was 
upgraded to endangered status following separation of the DPSs, and it 
remains endangered today. There is regular movement of both DPSs across 
this 144[deg] W longitude boundary (Jemison et al. 2013), however, due 
to the distance from this DPS boundary, it is likely that only eastern 
DPS Steller sea lions are present in the project area. Therefore, 
animals potentially affected by the project are assumed to be part of 
the eastern DPS.
    There are several mapped and regularly monitored long-term Steller 
sea lion haulouts surrounding Ketchikan, such as West Rocks (36 miles/
58 km) or Nose Point (37 miles/60 km), but none are known to occur 
within Tongass Narrows (Fritz et al. 2015). The nearest known Steller 
sea lion haulout is located approximately 20 miles (58 km) west/
northwest of Ketchikan on Grindall Island (Figure 4-1 in application). 
Summer counts of adult and juvenile sea lions at this haulout since 
2000 have averaged approximately 191 individuals, with a range from 6 
in 2009 to 378 in 2008. Only two winter surveys of this haulout have 
occurred. In March 1993, a total of 239 individuals were recorded, and 
in December 1994, a total of 211 individuals were recorded. No sea lion 
pups have been observed at this haulout during surveys. Although this 
is a limited and dated sample, it suggests that abundance may be 
consistent year-round at the Grindall Island haulout.
    No systematic studies of sea lion abundance or distribution have 
occurred in Tongass Narrows. Anecdotal reports suggest that Steller sea 
lions may be found in Tongass Narrows year-round, with an increase in 
abundance from March to early May during the herring spawning season, 
and another increase in late summer associated with salmon runs. 
Overall sea lion presence in Tongass Narrows tends to be lower in 
summer than in winter (FHWA 2017). During summer, Steller sea lions may 
aggregate outside the project area, at rookery and haulout sites. 
Monitoring during construction of the Ketchikan Ferry Terminal in 
summer (July 16 through August 17, 2016) did not record any Steller sea 
lions (ADOT&PF 2015); however, monitoring during construction of the 
Ward Cove Dock, located approximately 6 km northwest of the Project 
site, recorded 181 individual sea lions on 44 days between February and 
September 2020 (Power Systems & Supplies of Alaska, 2020). Most 
sightings occurred in February (45 sightings of 88 sea lions) and March 
(34 sightings of 45 sea lions); the fewest number of sightings were 
observed in May (1 sighting of 1 sea lion) (Power Systems & Supplies of 
Alaska, 2020). Sightings were of single individuals, pairs, and herds 
of up to 10 individuals.
    Sea lions are known to transit through Tongass Narrows while 
pursuing prey. Steller sea lions are also known to follow fishing 
vessels, and may congregate in small numbers at seafood processing 
facilities and hatcheries or at the mouths of rivers and creeks 
containing hatcheries, where large numbers of salmon congregate in late 
summer. Three seafood processing facilities are located east of the 
proposed berth location on Revilla Island, and two salmon hatcheries 
operated by the Alaska Department of Fish & Game (ADF&G) are located 
east of the project area. Steller sea lions may aggregate near the 
mouth of Ketchikan Creek, where a hatchery upstream supports a summer 
salmon run. The Creek mouth is more than 4 km (2.5 mi) from both ferry 
berth sites, and is positioned behind the cruise ship terminal and 
within the small boat harbor. In addition to these locations, anecdotal 
information from a local kayaking company suggests that there are 
Steller sea lions present at Gravina Point, near the southwest entrance 
to Tongass Narrows.
    A total of 181 Steller sea lions were sighted on 44 separate days 
during all months of Ward Cove Cruise Ship Dock construction (February 
through September, 2020) (Power Systems and

[[Page 5991]]

Supplies of Alaska, 2020). Most sightings occurred in February and 
March and the fewest sightings were in May. Sightings were of single 
individuals, pairs, and herds of up to 10 individuals.
    The DOT&PF implemented a marine mammal monitoring program in 
Tongass Narrows for recent previous construction components of the 
Tongass Narrows Project (84 FR 34134; July 17, 2019). Monitoring took 
place from October 2020 through February 2021 and May through June 
2021, and results indicated that Steller sea lion numbers were highest 
in January and February (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). 
Steller sea lions were observed in the Tongass Narrows Project area on 
49 of 88 days between October 2020 and June 2021 (DOT&PF 2020, 2021a, 
2021b, 2021c, 2021d). They were observed in every month that 
observations took place (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). Over 
the course of the 7 months of monitoring, there were 77 sightings of 92 
individual animals (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). Sightings 
of Steller sea lions were most frequent in January and February and 
least common in May and June (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). 
Sightings were primarily of single animals, but animals were also 
present in pairs and groups up to five sea lions (DOT&PF 2020, 2021a, 
2021b, 2021c, 2021d). This is consistent with Freitag (2017 as cited in 
83 FR 22009; May 11, 2018), though groups of up to 80 individuals have 
been observed (HDR, Inc. 2003). On average over the course of a year, 
Steller sea lions occur in Tongass Narrows approximately three or four 
times per week (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d).

Harbor Seal

    Harbor seals range from Baja California north along the west coasts 
of Washington, Oregon, California, British Columbia, and Southeast 
Alaska; west through the Gulf of Alaska, Prince William Sound, and the 
Aleutian Islands; and north in the Bering Sea to Cape Newenham and the 
Pribilof Islands. In 2010, harbor seals in Alaska were partitioned into 
12 separate stocks based largely on genetic structure (Allen and 
Angliss 2010). Harbor seals in Tongass Narrows are recognized as part 
of the Clarence Strait stock. Distribution of the Clarence Strait stock 
ranges from the east coast of Prince of Wales Island from Cape Chacon 
north through Clarence Strait to Point Baker and along the east coast 
of Mitkof and Kupreanof Islands north to Bay Point, including Ernest 
Sound, Behm Canal, and Pearse Canal (Muto et al. 2021). The latest 
stock assessment analysis indicates that the current 8-year estimate of 
the Clarence Strait population trend is +138 seals per year, with a 
probability that the stock is decreasing of 0.413 (Muto et al. 2021). 
Harbor seals haul out on rocks, reefs, beaches, and drifting glacial 
ice, and feed in marine, estuarine, and occasionally fresh waters. 
Harbor seals are generally non-migratory, with local movements 
associated with such factors as tides, weather, season, food 
availability, and reproduction (Muto, et al. 2021).
    No systematic studies of harbor seal abundance or distribution have 
occurred in Tongass Narrows. Aerial surveys conducted in August 2011 
did not record any harbor seal haulouts in Tongass Narrows, but several 
haulouts were located on the outer shores of Gravina Island (London et 
al. 2015). There is no known harbor seal haulout in Tongass Narrows 
although seals have been observed hauled out on docks in Ketchikan 
Harbor. The closest listed haulout is located off the tip of Gravina 
Island, approximately 8 km (5 mi) northwest of Ward Cove (AFSC 2018).
    Anecdotal observations indicate that harbor seals are common in 
Tongass Narrows, although no data exist to quantify abundance. Two 
salmon hatcheries operated by ADF&G are located east of the project 
area. Like Steller sea lions, harbor seals may aggregate near the mouth 
of Ketchikan Creek when salmon are running in summer. The creek mouth 
is more than 4 km (2.5 mi) from the project component sites, and is 
positioned behind both the cruise ship terminal and within the small 
boat harbor. In the project area, they tend to be more abundant during 
spring, summer and fall months when salmon are present in Ward Creek. 
Anecdotal evidence indicates that harbor seals typically occur in 
groups of 1-3 animals in Ward Cove (Spokely 2019). They were not 
observed in Tongass Narrows during a combined 63.5 hours of marine 
mammal monitoring that took place in 2001 and 2016 (OSSA 2001, 
Turnagain 2016). The COK conducted pinnacle rock blasting in December 
2019 and January 2020 near the vicinity of the proposed project and 
recorded a total of 21 harbor seal sightings of 24 individuals over 
76.2 hours of pre- and post-blast monitoring (Sitkiewicz 2020).
    Harbor seals were sighted during every month of construction 
(February through September, 2020) associated with the Ward Cove Cruise 
Ship Dock, with most sightings in February and March and the fewest in 
July (Power Systems and Supplies of Alaska, 2020). There were 247 
sighting events of 271 individuals. Sighting events were of solo 
individuals, pairs, and the occasional group of three.
    Marine mammal monitoring occurred near the project site from 
October 2020 to February 2021 and resumed in May 2021 during Phase 1 of 
the previously issued IHA (85 FR 673; January 7, 2020). Harbor seals 
were observed in the Tongass Narrows Project area in every month in 
which observations took place, except during October 2020 when only 3 
days of monitoring occurred (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). 
Harbor seals were sighted on 68 days out of 88 days of monitoring 
(DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). They were mostly sightings 
of single animals, but animals were also present in pairs and groups up 
to five seals (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). Sightings of 
harbor seals were consistent over the course of 7 months of 
intermittent monitoring; they were observed 5 to 6 days per week on 
average (DOT&PF 2020, 2021a, 2021b, 2021c, 2021d).

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et al. 
1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 3.

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                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
               Hearing group                  Generalized hearing range*
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen         7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,      150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true          275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus cruciger &
 L. australis).
Phocid pinnipeds (PW) (underwater) (true     50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea     60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al. 2006; Kastelein et al. 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Eight marine mammal species (six 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 2. Of the 
cetacean species that may be present, two 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, Dall's porpoise and Kogia spp.).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species or 
stocks.
    Acoustic effects on marine mammals during the specified activity 
can occur from impact and vibratory pile driving and removal and use of 
DTH equipment. The effects of underwater noise from ADOT's proposed 
activities have the potential to result in Level A or Level B 
harassment of marine mammals in the action area.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far (ANSI 1995). The sound level of an area is 
defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., waves, wind, 
precipitation, earthquakes, ice, atmospheric sound), biological (e.g., 
sounds produced by marine mammals, fish, and invertebrates), and 
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al. 1995). The result is that, depending 
on the source type and its intensity, sound from the specified activity 
may be a negligible addition to the local environment or could form a 
distinctive signal that may affect marine mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving and removal, and 
use of DTH equipment. The sounds produced by these activities fall into 
one of two general sound types: Impulsive and non-impulsive. Impulsive 
sounds (e.g., explosions, gunshots, sonic booms, impact pile driving) 
are typically transient, brief (less than 1 second), broadband, and 
consist of high peak sound pressure with rapid rise time and rapid 
decay (ANSI 1986; NIOSH 1998; NMFS 2018). Non-impulsive sounds (e.g. 
aircraft, machinery operations such as drilling or dredging, vibratory 
pile driving, and active sonar systems) can be broadband, narrowband or 
tonal, brief or prolonged (continuous or intermittent), and typically 
do not have the high peak sound pressure with rapid rise/decay time 
that impulsive sounds do (ANSI 1995; NIOSH 1998; NMFS 2018). The 
distinction between these two sound types is important because they 
have differing potential to cause physical effects, particularly with 
regard to hearing (e.g., Ward 1997 in Southall et al. 2007).
    Three types of hammers would be used on this project: Impact, 
vibratory, and DTH. Impact hammers operate by repeatedly dropping and/
or pushing a heavy piston onto a pile to drive the pile into the 
substrate. Sound generated by impact hammers is characterized by rapid 
rise times and high peak levels, a potentially injurious combination 
(Hastings and Popper 2005). Vibratory hammers install piles by 
vibrating them and allowing the weight of the hammer to push them into 
the sediment. Vibratory hammers produce significantly less sound than 
impact hammers. Peak Sound Pressure Levels (SPLs) may be 180 dB or 
greater, but are generally 10 to 20 dB lower than SPLs generated during 
impact pile driving of the same-sized pile (Oestman et al.

[[Page 5993]]

2009). Rise time is slower, reducing the probability and severity of 
injury, and sound energy is distributed over a greater amount of time 
(Nedwell and Edwards 2002; Carlson et al. 2005).
    A DTH hammer is essentially a drill bit that drills through the 
bedrock using a rotating function like a normal drill, in concert with 
a hammering mechanism operated by a pneumatic (or sometimes hydraulic) 
component integrated into to the DTH hammer to increase speed of 
progress through the substrate (i.e., it is similar to a ``hammer 
drill'' hand tool). The sounds produced by the DTH method contain both 
a continuous non-impulsive component from the drilling action and an 
impulsive component from the hammering effect. Therefore, we treat DTH 
systems as both impulsive and continuous, non-impulsive sound source 
types simultaneously.
    The likely or possible impacts of ADOT's proposed activity on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of the equipment and personnel; however, any impacts to marine 
mammals are expected to primarily be acoustic in nature. Acoustic 
stressors include effects of heavy equipment operation during pile 
installation and removal and use of DTH.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal and DTH is the primary means 
by which marine mammals may be harassed from ADOT's specified activity. 
In general, animals exposed to natural or anthropogenic sound may 
experience physical and psychological effects, ranging in magnitude 
from none to severe (Southall et al. 2007, 2019). In general, exposure 
to pile driving and DTH noise has the potential to result in auditory 
threshold shifts and behavioral reactions (e.g., avoidance, temporary 
cessation of foraging and vocalizing, changes in dive behavior). 
Exposure to anthropogenic noise can also lead to non-observable 
physiological responses such an increase in stress hormones. Additional 
noise in a marine mammal's habitat can mask acoustic cues used by 
marine mammals to carry out daily functions such as communication and 
predator and prey detection. The effects of pile driving and DTH noise 
on marine mammals are dependent on several factors, including, but not 
limited to, sound type (e.g., impulsive vs. non-impulsive), the 
species, age and sex class (e.g., adult male vs. mom with calf), 
duration of exposure, the distance between the pile and the animal, 
received levels, behavior at time of exposure, and previous history 
with exposure (Wartzok et al. 2004; Southall et al. 2007). Here we 
discuss physical auditory effects (threshold shifts) followed by 
behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al. 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS 2018). Available data from 
humans and other terrestrial mammals indicate that a 40 dB threshold 
shift approximates PTS onset (see Ward et al. 1958, 1959; Ward 1960; 
Kryter et al. 1966; Miller 1974; Ahroon et al. 1996; Henderson et al. 
2008). PTS levels for marine mammals are estimates, as with the 
exception of a single study unintentionally inducing PTS in a harbor 
seal (Kastak et al. 2008), there are no empirical data measuring PTS in 
marine mammals largely due to the fact that, for various ethical 
reasons, experiments involving anthropogenic noise exposure at levels 
inducing PTS are not typically pursued or authorized (NMFS 2018).
    Temporary Threshold Shift (TTS)--A temporary, reversible increase 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS 2018). Based on data from cetacean TTS measurements (see 
Southall et al. 2007), a TTS of 6 dB is considered the minimum 
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et 
al. 2000; Finneran et al. 2000, 2002). As described in Finneran (2015), 
marine mammal studies have shown the amount of TTS increases with 
cumulative sound exposure level (SELcum) in an accelerating fashion: At 
low exposures with lower SELcum, the amount of TTS is typically small 
and the growth curves have shallow slopes. At exposures with higher 
SELcum, the growth curves become steeper and approach linear 
relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
masking, below). For example, a marine mammal may be able to readily 
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal 
is traveling through the open ocean, where ambient noise is lower and 
there are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts. We note that reduced hearing sensitivity as 
a simple function of aging has been observed in marine mammals, as well 
as humans and other taxa (Southall et al. 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and five species of pinnipeds exposed to a limited 
number of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (Finneran 2015). TTS was not observed in trained 
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to 
impulsive noise at levels matching previous predictions of TTS onset 
(Reichmuth et al. 2016). In general, harbor seals and harbor porpoises 
have a lower TTS onset than other measured pinniped or cetacean species 
(Finneran 2015). Additionally, the existing marine

[[Page 5994]]

mammal TTS data come from a limited number of individuals within these 
species. No data are available on noise-induced hearing loss for 
mysticetes. For summaries of data on TTS in marine mammals or for 
further discussion of TTS onset thresholds, please see Southall et al. 
(2007), Finneran and Jenkins (2012), Finneran (2015), and Table 5 in 
NMFS (2018).
    Installing piles requires a combination of impact pile driving, 
vibratory pile driving, and DTH. For the project, these activities may 
occur at the same time (up to two hammers of any combination of hammer/
drill type), though such an occurrence is anticipated to be infrequent 
and for short durations on any given day, given that pile installation 
and removal occurs intermittently to allow for adjusting piles and 
measuring and documenting progress. Therefore, there would likely be 
pauses in activities producing the sound during each day. Given these 
pauses and that many marine mammals are likely moving through the 
project area and not remaining for extended periods of time, the 
potential for TS declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal and DTH also has the potential to behaviorally disturb marine 
mammals. Available studies show wide variation in response to 
underwater sound; therefore, it is difficult to predict specifically 
how any given sound in a particular instance might affect marine 
mammals perceiving the signal. If a marine mammal does react briefly to 
an underwater sound by changing its behavior or moving a small 
distance, the impacts of the change are unlikely to be significant to 
the individual, let alone the stock or population. However, if a sound 
source displaces marine mammals from an important feeding or breeding 
area for a prolonged period, impacts on individuals and populations 
could be significant (e.g., Lusseau and Bejder 2007; Weilgart 2007; NRC 
2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff 2006). Behavioral responses to sound are 
highly variable and context-specific and any reactions depend on 
numerous intrinsic and extrinsic factors (e.g., species, state of 
maturity, experience, current activity, reproductive state, auditory 
sensitivity, time of day), as well as the interplay between factors 
(e.g., Richardson et al. 1995; Wartzok et al. 2003; Southall et al. 
2007; Weilgart 2007; Archer et al. 2010). Behavioral reactions can vary 
not only among individuals but also within an individual, depending on 
previous experience with a sound source, context, and numerous other 
factors (Ellison et al. 2012), and can vary depending on 
characteristics associated with the sound source (e.g., whether it is 
moving or stationary, number of sources, distance from the source). In 
general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. Please see Appendices B and C of Southall et 
al. (2007) for a review of studies involving marine mammal behavioral 
responses to sound.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al. 
2001; Nowacek et al. 2004; Madsen et al. 2006; Yazvenko et al. 2007). A 
determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    In 2016, ADOT documented observations of marine mammals during 
construction activities (i.e., pile driving and DTH) at the Kodiak 
Ferry Dock (ABR 2016) in the Gulf of Alaska. In the marine mammal 
monitoring report for that project, 1,281 Steller sea lions were 
observed within the estimated Level B harassment zone during pile 
driving or DTH (i.e., documented as potential take by Level B 
harassment). Of these, 19 individuals demonstrated an alert behavior, 7 
were fleeing, and 19 swam away from the project site. All other animals 
(98 percent) were engaged in activities such as milling, foraging, or 
fighting and did not change their behavior. In addition, two sea lions 
approached within 20 m of active vibratory pile driving activities. 
Three harbor seals were observed within the disturbance zone during 
pile driving activities; none of them displayed disturbance behaviors. 
Fifteen killer whales and three harbor porpoise were also observed 
within the Level B harassment zone during pile driving. The killer 
whales were travelling or milling while all harbor porpoises were 
travelling. No signs of disturbance were noted for either of these 
species. Given the similarities in species, activities, and habitat, we 
expect similar behavioral responses of marine mammals to the ADOT's 
specified activity. That is, disturbance, if any, is likely to be 
temporary and localized (e.g., small area movements). Monitoring 
reports from other recent pile driving and DTH projects in Alaska have 
observed similar behaviors, for example, the Biorka Island Dock 
Replacement Project (https://www.fisheries.noaa.gov/action/incidental-take-authorization-faa-biorka-island-dock-replacement-project-sitka-ak).
    Stress responses--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

[[Page 5995]]

``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), however 
distress is an unlikely result of this project based on observations of 
marine mammals during previous, similar projects in the area.
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al. 1995). Masking occurs when 
the receipt of a sound is interfered with by another coincident sound 
at similar frequencies and at similar or higher intensity, and may 
occur whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal and DTH that have the potential to cause behavioral 
harassment, depending on their distance from these activities. 
Cetaceans are not expected to be exposed to airborne sounds that would 
result in harassment as defined under the MMPA.
    Airborne noise would primarily be an issue for pinnipeds that are 
swimming or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. We recognize that 
pinnipeds in the water could be exposed to airborne sound that may 
result in behavioral harassment when looking with their heads above 
water. Most likely, airborne sound would cause behavioral responses 
similar to those discussed above in relation to underwater sound. For 
instance, anthropogenic sound could cause hauled-out pinnipeds to 
exhibit changes in their normal behavior, such as reduction in 
vocalizations, or cause them to temporarily abandon the area and move 
further from the source. However, these animals would previously have 
been `taken' because of exposure to underwater sound above the 
behavioral harassment thresholds, which are in all cases larger than 
those associated with airborne sound. Thus, the behavioral harassment 
of these animals is already accounted for in these estimates of 
potential take. Therefore, we do not believe that authorization of 
incidental take resulting from airborne sound for pinnipeds is 
warranted, and airborne sound is not discussed further here.

Marine Mammal Habitat Effects

    ADOT's proposed activities at the project area would not result in 
permanent negative impacts to habitats used directly by marine mammals, 
but may have potential short-term impacts to food sources such as 
forage fish and may affect acoustic habitat (see masking discussion 
above). There are no known foraging hotspots or other ocean bottom 
structure of significant biological importance to marine mammals 
present in the marine waters of the project area during the 
construction window, but there are times of increased foraging during 
periods of forage fish and salmonid spawning. ADOT's construction 
activities in Tongass Narrows could have localized, temporary impacts 
on marine mammal habitat and their prey by increasing in-water sound 
pressure levels and slightly decreasing water quality. Increased noise 
levels may affect acoustic habitat (see masking discussion above) and 
adversely affect marine mammal prey in the vicinity of the project area 
(see discussion below). During DTH, impact and vibratory pile driving 
or removal, elevated levels of underwater noise would ensonify a 
portion of Tongass Narrows and nearby waters where both fishes and 
mammals occur and could affect foraging success. Additionally, marine 
mammals may avoid the area during construction, however, displacement 
due to noise is expected to be temporary and is not expected to result 
in long-term effects to the individuals or populations. Construction 
activities are of short duration and would likely have temporary 
impacts on marine mammal habitat through increases in underwater and 
airborne sound.
    The area likely impacted by the project includes much of Tongass 
Narrows, but overall this area is relatively small compared to the 
available habitat in the surrounding area including Revillagigedo 
Channel, Behm Canal, and Clarence Strait. Pile installation/removal and 
DTH may temporarily increase turbidity resulting from suspended 
sediments. Any increases would be temporary, localized, and minimal. In 
general, turbidity associated with pile installation is localized to 
about a 25-ft radius around the pile (Everitt et al. 1980). Cetaceans 
are not expected to be close enough to the project pile driving areas 
to experience effects of turbidity, and pinnipeds could avoid localized 
areas of turbidity. Therefore, the impact from increased turbidity 
levels is expected to minimal for marine mammals. Furthermore, pile 
driving and removal at the project site would not obstruct movements or 
migration of marine mammals.
    In-water Construction Effects on Potential Prey--Construction 
activities

[[Page 5996]]

would produce continuous (i.e., vibratory pile driving and DTH) and 
intermittent (i.e. impact driving and DTH) sounds. Sound may affect 
marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton). Marine mammal prey varies by species, season, and 
location. Here, we describe studies regarding the effects of noise on 
known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann 1999; Fay 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fishes hear sounds using pressure and 
particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al. 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    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. The reaction of 
fish to noise depends on the physiological state of the fish, past 
exposures, motivation (e.g., feeding, spawning, migration), and other 
environmental factors. Hastings and Popper (2005) identified several 
studies that suggest fish may relocate to avoid certain areas of sound 
energy. Additional studies have documented effects of pile driving on 
fish; several are based on studies in support of large, multiyear 
bridge construction projects (e.g., Scholik and Yan 2001, 2002; Popper 
and Hastings 2009). Several studies have demonstrated that impulse 
sounds might affect the distribution and behavior of some fishes, 
potentially impacting foraging opportunities or increasing energetic 
costs (e.g., Fewtrell and McCauley, 2012; Pearson et al. 1992; Skalski 
et al. 1992; Santulli et al. 1999; Paxton et al. 2017). However, some 
studies have shown no or slight reaction to impulse sounds (e.g., Pena 
et al. 2013; Wardle et al. 2001; Jorgenson and Gyselman, 2009; Cott et 
al. 2012).
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours 
for one species. Impacts would be most severe when the individual fish 
is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al. 2012b; Casper et al. 2013).
    The most likely impact to fish from pile driving and removal and 
DTH activities at the project area would be temporary behavioral 
avoidance of the area. The duration of fish avoidance of this area 
after pile driving stops is unknown, but a rapid return to normal 
recruitment, distribution and behavior is anticipated. Any behavioral 
avoidance by fish of the disturbed area would still leave significantly 
large areas of fish and marine mammal foraging habitat in the nearby 
vicinity in Revillagigedo Channel, Behm Canal, and Clarence Strait. 
Additionally, the City of Ketchikan within Tongass Narrows has a busy 
industrial water front, and human impact lessens the value of the area 
as foraging habitat. There are times of known seasonal marine mammal 
foraging in Tongass Narrows around fish processing/hatchery 
infrastructure or when fish are congregating, but the impacted areas of 
Tongass Narrows are a small portion of the total foraging habitat 
available in the region. In general, impacts to marine mammal prey 
species are expected to be minor and temporary due to the short 
timeframe of the project.
    Construction activities, in the form of increased turbidity, have 
the potential to adversely affect eulachon, herring, and juvenile 
salmonid outmigratory routes in the project area. Salmon and forage 
fish, like eulachon and herring, form a significant prey base for 
Steller sea lions and are major components of the diet of many other 
marine mammal species that occur in the project area. Increased 
turbidity is expected to occur only in the immediate vicinity of 
construction activities and to dissipate quickly with tidal cycles. 
Given the limited area affected and high tidal dilution rates any 
effects on fish are expected to be minor.
    Additionally, the presence of transient killer whales means some 
marine mammal species are also possible prey (harbor seals, harbor 
porpoises). ADOT's pile driving, pile removal and DTH activities are 
expected to result in limited instances of take by Level B and Level A 
harassment on these smaller marine mammals. That, as well as the fact 
that ADOT is impacting a small portion of the total available marine 
mammal habitat means that there would be minimal impact on these marine 
mammals as prey.
    In summary, given the short daily duration of sound associated with 
individual pile driving and DTH events and the small area being 
affected relative to available nearby habitat, pile driving and DTH 
activities associated with the proposed action are not likely to have a 
permanent, adverse effect on any fish habitat, or populations of fish 
species or other prey. Thus, we conclude that impacts of the specified 
activity are not likely to have more than short-term adverse effects on 
any prey habitat or populations of prey species. Further, any impacts 
to marine mammal habitat are not expected to result in significant or 
long-term consequences for individual marine mammals, or to contribute 
to adverse impacts on their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of the acoustic sources (i.e., impact and vibratory pile driving and 
DTH) have the potential to result in disruption of behavioral patterns 
for individual marine mammals. There is also some potential for 
auditory injury (Level A harassment) to result, primarily for 
mysticetes, high frequency species and phocids because predicted 
auditory injury zones are larger than for mid-frequency species and 
otariids. Auditory injury is unlikely to occur for mid-frequency 
species and otariids. The proposed mitigation and monitoring

[[Page 5997]]

measures are expected to minimize the severity of such taking to the 
extent practicable.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed or incur some 
degree of permanent hearing impairment; (2) the area or volume of water 
that will be ensonified above these levels in a day; (3) the density or 
occurrence of marine mammals within these ensonified areas; and, (4) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of takes, additional information that can qualitatively 
inform take estimates is also sometimes available (e.g., previous 
monitoring results or average group size). Below, we describe the 
factors considered here in more detail and present the proposed take 
estimate.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al. 2007, Ellison 
et al. 2012). Based on what the available science indicates and the 
practical need to use a threshold based on a factor that is both 
predictable and measurable for most activities, NMFS uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS predicts that marine mammals are likely to 
be behaviorally harassed in a manner we consider Level B harassment 
when exposed to underwater anthropogenic noise above received levels of 
120 dB re 1 microPascal ([mu]Pa) (root mean square (rms)) for 
continuous (e.g., vibratory pile-driving, DTH) and above 160 dB re 1 
[mu]Pa (rms) for non-explosive impulsive (e.g., seismic airguns) or 
intermittent (e.g., scientific sonar) sources. This take estimation 
includes disruption of behavioral patterns resulting directly in 
response to noise exposure (e.g., avoidance), as well as that resulting 
indirectly from associated impacts such as TTS or masking. ADOT's 
proposed activity includes the use of continuous (vibratory pile 
driving/removal and DTH) and impulsive (impact pile driving and DTH) 
sources, and therefore both the 120 and 160 dB re 1 [mu]Pa (rms) 
thresholds are applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). ADOT's proposed activity includes the use 
of impulsive (impact pile driving and DTH) and non-impulsive (vibratory 
pile driving/removal and DTH) sources.
    These thresholds are provided in Table 4 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

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

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.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., impact pile driving, vibratory 
pile driving, vibratory pile removal, and DTH).
    In order to calculate distances to the Level A harassment and Level 
B harassment sound thresholds for the methods and piles being used in 
this project, NMFS used acoustic monitoring data from other locations 
to develop source levels for the various pile types,

[[Page 5998]]

sizes and methods (Table 5). Note that piles of differing sizes have 
different sound source levels (SSLs).
    Empirical data from recent ADOT sound source verification (SSV) 
studies at Ketchikan were used to estimate SSLs for vibratory and 
impact driving of 30-inch steel pipe piles (Denes et al. 2016). Data 
from Ketchikan was used because of its proximity to this proposed 
project in Tongass Narrows. However, the use of data from Alaska sites 
was not appropriate in all instances. Details are described below.
    For vibratory driving of 24-inch steel piles, data from a Navy pile 
driving project in the Puget Sound, WA was reviewed (Navy 2015). From 
this review, ADOT determined the Navy's suggested source value of 161 
dB rms was an appropriate proxy source value, and NMFS concurs. Because 
the source value of smaller piles of the same general type (steel in 
this case) are not expected to exceed a larger pile, the same 161 dB 
rms source value was used for 20-inch steel piles. This assumption 
conforms with source values presented in Navy (2015) for a project 
using 16-inch steel piles at Naval Base Kitsap in Bangor, WA.
    ADOT used source values of 177 dB SEL and 190 dB rms for impact 
driving of 24-inch and 20-inch steel piles. These values were 
determined based on summary values presented in Caltrans (2015) for 
impact driving of 24-inch steel piles. NMFS concurs that the same 
source value was an acceptable proxy for impact driving of 20-inch 
steel piles.
    Sound pressure levels in the water column resulting from DTH are 
not well studied. Because DTH hole creation includes both impulsive and 
continuous components, NMFS guidance currently recommends that it be 
treated as a continuous sound for Level B calculations and as an 
impulsive sound for Level A calculations (Table 11). In the absence of 
data specific to different hole sizes, current NMFS guidance recommends 
that calculation of Level B zones for DTH use the same continuous SSL 
of 167 dB SEL for all hole sizes (Heyvaert and Reyff 2021). Recommended 
SSLs for 30-inch and 24-inch holes as well as 8-inch holes for tension 
anchors and micropiles for use in the calculation of Level A harassment 
thresholds are provided by current NMFS guidance and in Table 5.

Table 5--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Installation, DTH,
                                           and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
Method and pile type                                      SSL at 10 m                   Literature source
Vibratory hammer                                            dB rms                      ........................
----------------------------------------------------------------------------------------------------------------
30-inch steel piles...................                        162                       Denes et al. 2016.
----------------------------------------------------------------------------------------------------------------
24-inch steel piles...................                        161                       Navy 2015.
----------------------------------------------------------------------------------------------------------------
20-inch steel piles...................                        161                       Navy 2015.
----------------------------------------------------------------------------------------------------------------
    DTH of rock sockets and tension                         dB rms
                anchors
----------------------------------------------------------------------------------------------------------------
All pile diameters....................                        167                       Heyvaert and Reyff 2021.
----------------------------------------------------------------------------------------------------------------


 
   DTH of rock sockets and tension
               anchors                         dB SELss                 dB peak
----------------------------------------------------------------------------------------------------------------
30-inch rock socket..................                     164                      194   Reyff and Heyvaert
                                                                                          2019; Reyff 2020;
                                                                                          Denes et al. 2016.
----------------------------------------------------------------------------------------------------------------
24-inch rock socket..................                     159                      184   Heyvaert and Reyff
                                                                                          2021.
----------------------------------------------------------------------------------------------------------------
8-inch tension anchor/micropile......                     144                      170   Reyff 2020.
----------------------------------------------------------------------------------------------------------------


 
            Impact hammer                  dB rms           dB SEL          dB peak
----------------------------------------------------------------------------------------------------------------
30-inch steel piles.................             195              181              209   Denes et al. 2016.
----------------------------------------------------------------------------------------------------------------
24-inch steel piles.................             190              177              203   Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
20-inch steel piles.................             190              177              202   Caltrans 2015.
----------------------------------------------------------------------------------------------------------------
Note: It is assumed that noise levels during pile installation and removal are similar. SEL = sound exposure
  level; dB peak = peak sound level; rms = root mean square.

    Simultaneous use of two impact, vibratory, or DTH hammers, or any 
combination of those equipment, could occur. Such occurrences are 
anticipated to be infrequent, would be for short durations on any given 
day, and ADOT anticipates that no more than two hammers would be 
operated concurrently. Simultaneous use of two hammers or DTH systems 
could occur at the same project site, or at two different, but nearby 
project sites. Simultaneous use of hammers could result in increased 
SPLs and harassment zone sizes given the proximity of the component 
driving sites and the physical rules of decibel addition. ADOT 
anticipates that concurrent use of two hammers producing continuous 
noise could occur on 44 days, which is half the anticipated number of 
days of construction (91 days) and represents complete overlap between 
the two contracts and/or represents use of two hammers by a single 
contractor. Although it is unlikely that overlap would be complete, 
ADOT anticipates, and NMFS concurs, this scenario represents the 
potential worst case scenario, given that a more accurate estimate is 
not possible, and concurrent operation of hammers would be incidental. 
Given that the use of more than one hammer for pile installation on the 
same day (whether simultaneous or not) would increase the number of 
piles installed per day, this would be anticipated to result in a 
reduction of the total number of days of pile installation. Table 6 
shows how potential scenarios would reduce the total number of pile 
driving days and weeks. However, as described in the Marine Mammal 
Occurrence and Take Calculation and Estimation section below, ADOT has 
conservatively calculated take with the assumption that pile driving 
would occur on all 91 days.

[[Page 5999]]



 Table 6--Calculated Reduction of Pile Driving Days Based on Percentage of Project Days With Two Hammers in Use
----------------------------------------------------------------------------------------------------------------
                                                   Days of work
                                      Days of        completed    Remaining days   Total number
         Percent overlap              overlap     during overlap   of work with     of days  of   Weeks  of work
                                                    (2 hammers)    single hammer       work
----------------------------------------------------------------------------------------------------------------
0...............................             0.0             0.0            91.0            91.0            15.2
10..............................             9.1            18.2            72.8            81.9            13.7
20..............................            18.2            36.4            54.6            72.8            12.1
30..............................            27.3            54.6            36.4            63.7            10.6
40..............................            36.4            72.8            18.2            54.6             9.1
50..............................            45.5            91.0             0.0            45.5             7.6
----------------------------------------------------------------------------------------------------------------

    NMFS (2018b) handles overlapping sound fields created by the use of 
more than one hammer differently for impulsive (impact hammer and Level 
A harassment zones for drilling with a DTH hammer) and continuous sound 
sources (vibratory hammer and Level B harassment zones for drilling 
with a DTH hammer; Table 7) and differently for impulsive sources with 
rapid impulse rates of multiple strikes per second (DTH) and slow 
impulse rates (impact hammering) (NMFS 2021). It is unlikely that the 
two impact hammers would strike at the same instant, and therefore, the 
SPLs would not be adjusted regardless of the distance between impact 
hammers. In this case, each impact hammer would be considered to have 
its own independent Level A harassment and Level B harassment zones.
    When two DTH hammers operate simultaneously their continuous sound 
components overlap completely in time. When the Level B isopleth of one 
DTH sound source encompasses the isopleth of another DTH sound source, 
the sources are considered additive and combined using the following 
rules (Table 7). The method described below was based on one created by 
Washington State Department of Transportation (WSDOT) and has been 
updated and modified by NMFS (WSDOT 2020). For addition of two 
simultaneous DTH hammers, the difference between the two SSLs is 
calculated, and if that difference is between 0 and 1 dB, 3 dB are 
added to the higher SSL; if difference is between 2 or 3 dB, 2 dB are 
added to the highest SSL; if the difference is between 4 to 9 dB, 1 dB 
is added to the highest SSL; and with differences of 10 or more 
decibels, there is no addition.
    When two continuous noise sources, such as vibratory hammers, have 
overlapping sound fields, there is potential for higher sound levels 
than for non-overlapping sources.
    When two or more vibratory hammers are used simultaneously, and the 
isopleth of one sound source encompasses the isopleth of another sound 
source, the sources are considered additive and source levels are 
combined using the rules in Table 7, similar to described above for 
DTH.

               Table 7--Rules for Combining Sound Source Levels Generated During Pile Installation
----------------------------------------------------------------------------------------------------------------
           Hammer types               Difference in SSL           Level A zones              Level B zones
----------------------------------------------------------------------------------------------------------------
Vibratory, Impact.................  Any..................  Use impact zones..........  Use largest zone.
Impact, Impact....................  Any..................  Use zones for each pile     Use zone for each pile
                                                            size and number of          size.
                                                            strikes.
Vibratory, Vibratory or DTH, DTH..  0 or 1 dB............  Add 3 dB to the higher      Add 3 dB to the higher
                                    2 or 3 dB............   source level.               source level.
                                                           Add 2 dB to the higher      Add 2 dB to the higher
                                                            source level.               source level.
                                    4 to 9 dB............  Add 1 dB to the higher      Add 1 dB to the higher
                                    10 dB or more........   source level.               source level.
                                                           Add 0 dB to the higher      Add 0 dB to the higher
                                                            source level.               source level.
----------------------------------------------------------------------------------------------------------------

    During pile driving, it is common for pile installation to start 
and stop multiple times as each pile is adjusted and its progress is 
measured and documented, though as stated above, for short durations, 
it is anticipated that multiple hammers could be in use simultaneously. 
Following an approach modified from WSDOT in their Biological 
Assessment manual (WSDOT 2020) and described in Table 8, decibel 
addition calculations were carried out for possible combinations of 
pile driving and DTH throughout the project area. The source levels 
included in Table 8 are used to estimate the Level A harassment zones 
and the Level B harassment zones.

Table 8--Combined SSLs (dB at 10 m) Generated During Pile Installation and Removal for Combinations of Two Pieces of Equipment: Impact Hammer, Vibratory
                                                             Hammer, and Down-the-Hole Drill
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              Vibratory (RMS)               DTH (RMS)                  DTH (SEL)
                                                      --------------------------------------------------------------------------------------------------
                        Method                           Pile diameter      20       24       30       8        24       30       8        24       30
                                                      --------------------------------------------------------------------------------------------------
                                                                  SSL      161      161      162      167      167      167      144      159      164
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory (RMS)......................................       20      161      164      164      165      168      168      168  .......  .......  .......
                                                            24      161      164      164      165      168      168      168  .......  .......  .......
                                                            30      162      165      165      165      168      168      168  .......  .......  .......
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH (RMS)............................................        8      167      168      168      168      170      170      170  .......  .......  .......

[[Page 6000]]

 
                                                            24      167      168      168      168      170      170      170  .......  .......  .......
                                                            30      167      168      168      168      170      170      170  .......  .......  .......
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH (SEL)............................................        8      144  .......  .......  .......  .......  .......  .......      147      159      164
                                                            24      159  .......  .......  .......  .......  .......  .......      159      162      165
                                                            30      164  .......  .......  .......  .......  .......  .......      164      165      167
--------------------------------------------------------------------------------------------------------------------------------------------------------

    No addition is warranted for impact pile driving in combination 
with vibratory or impact pile driving or DTH (NMFS 2021).

Level B Harassment Zones

    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B * Log10 (R1/R2),

Where:

TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, which is the most appropriate 
assumption for ADOT's proposed activity in the absence of specific 
modelling.
    All Level B harassment isopleths are reported in Table 9 and Table 
10 below. It should be noted that based on the geography of Tongass 
Narrows and the surrounding islands, sound would not reach the full 
distance of the Level B harassment isopleth in most directions. 
Generally, due to interaction with land, only a thin slice of the 
possible area is ensonified to the full distance of the Level B 
harassment isopleth.
    The size of the Level B harassment zone during concurrent operation 
of two vibratory or DTH hammers would depend on the combination of 
sound sources and the decibel addition of two hammers producing 
continuous noise. Table 9 shows the distances to Level B harassment 
isopleths during simultaneous hammering from two sources, based on the 
combined SSL. Because the calculated Level B harassment isopleths for 
two sources are dependent upon the combined SSL, the Level B harassment 
zone for each combined sound source level included in Table 9 is 
consistent, regardless of the equipment combination. Please refer to 
Table 8 to determine which sound sources apply to each Combined SSL.
    As noted previously, pile installation often involves numerous 
stops and starts of the hammer for each pile. Therefore, decibel 
addition is applied only when the adjacent continuous sound sources 
experience overlapping sound fields, which generally requires close 
proximity of driving locations.

  Table 9-- Level B Harassment Isopleths for Multiple Vibratory Hammer
                                Additions
------------------------------------------------------------------------
                                                              Level B
                                                            harassment
                    Combined SSL (dB)                      isopleth (m)
                                                                \a\
------------------------------------------------------------------------
164.....................................................           8,577
165.....................................................          10,000
166.....................................................          11,659
167.....................................................          13,594
168.....................................................          15,849
169.....................................................          18,478
170.....................................................          21,544
------------------------------------------------------------------------
\a\ These larger zones are truncated to the southeast by islands, which
  prevent propagation of sound in that direction beyond the confines of
  Tongass Narrows. To the northwest of Tongass Narrows, combined sound
  levels that exceed 167 dB rms extend into Clarence Strait before
  attenuating to sound levels that are anticipated to be below 120 dB
  rms.


Table 10--Level B Harassment Isopleths for Single Hammer Use by Activity
                              and Pile Size
------------------------------------------------------------------------
                                                              Level B
                Activity                   Pile diameter    harassment
                                              (inch)       isopleth (m)
------------------------------------------------------------------------
Vibratory Installation..................              30           6,310
                                                      24           5,412
                                                      20  ..............
Vibratory Removal.......................              24  ..............
DTH Rock Sockets........................              30          13,594

[[Page 6001]]

 
                                                      24  ..............
DTH Tension Anchor/Micropile............               8  ..............
Impact Installation.....................              30           2,154
                                                      24           1,000
                                                      20           1,000
------------------------------------------------------------------------

Level A Harassment Zones

    When the NMFS Technical Guidance (2016) was published, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of takes by Level A harassment. However, these tools offer 
the best way to predict appropriate isopleths when more sophisticated 
3D modeling methods are not available, and NMFS continues to develop 
ways to quantitatively refine these tools, and will qualitatively 
address the output where appropriate. For stationary sources such as 
pile driving or removal and DTH using any of the methods discussed 
above, NMFS User Spreadsheet predicts the closest distance at which, if 
a marine mammal remained at that distance the whole duration of the 
activity, it would incur PTS. Inputs used in the User Spreadsheet are 
reported in Table 11 and Table 12, and the resulting isopleths are 
reported below in Table 13 and Table 14. Pile installation and removal 
can occur at variable rates, from a few minutes one day to many hours 
the next. ADOT anticipates that one permanent pile would be installed 
per day on 27 non-consecutive days, two temporary piles would be 
installed per day on 10 non-consecutive days, and two temporary piles 
would be removed per day on 10 days.
BILLING CODE 3510-22-P

[[Page 6002]]

[GRAPHIC] [TIFF OMITTED] TN02FE22.002

BILLING CODE 3510-22-C
    Regarding implications for Level A harassment zones when two 
vibratory hammers are operating concurrently, given the small size of 
the estimated Level A harassment isopleths for all hearing groups 
during vibratory pile driving, the zone of any two hammers would not be 
expected to overlap. Therefore, compounding effects of multiple 
vibratory hammers operating concurrently are not anticipated, and NMFS 
has treated each source independently.
    Regarding implications for Level A harassment zones when one 
vibratory hammer and one DTH hammer are operating concurrently, 
combining isopleths for these sources is difficult for a variety of 
reasons. First, vibratory pile driving relies upon non-impulsive PTS 
thresholds, while DTH/rock hammers use impulsive thresholds. Second, 
vibratory pile driving account for the duration to drive a pile, while 
DTH account for strikes per pile. Thus, it is difficult to measure 
sound on the same scale and combine isopleths from these impulsive and 
non-impulsive, continuous sources. Therefore, NMFS has treated each 
source independently at this time.
    Regarding the operation of two DTH hammers concurrently, since DTH 
hammers are capable of multiple strikes per second, there is potential 
for multiple DTH/rock hammer sources' isopleths to overlap in space and 
time (a higher strike rate indicates a greater potential for overlap). 
Therefore, NMFS has calculated distances to Level A harassment 
isopleths, by hearing group

[[Page 6003]]

for simultaneous use of two DTH hammers (Table 14), using NMFS' User 
Spreadsheet. The inputs for these calculations are outlined in Table 
12. When the Level A isopleth of one DTH sound source encompasses the 
isopleth of another DTH sound source, the sources are considered 
additive and combined using the rules in Table 7 as described above. 
The number of piles per day is altered to reflect only a single pile 
for all those that overlap in space and time (i.e., no double counting 
of overlapping piles). The maximum strike rate and duration of the two 
DTH systems is used in the User Spreadsheet calculations.

 Table 12--NMFS User Spreadsheet Inputs for Simultaneous Use of Two DTH
                                 Hammers
------------------------------------------------------------------------
                                                           E.2) DTH pile
                  Spreadsheet tab used                        driving
------------------------------------------------------------------------
Weighting Factor Adjustment (kHz).......................               2
SSL (dB SEL at 10m): \a\
    8-in pile/8-in pile.................................             147
    8-in pile, 24-in pile...............................             159
    8-in pile, 30-in pile...............................             164
    24-in pile, 24-in pile..............................             162
    24-in pile, 30-in pile..............................             165
    30-in pile, 30-in pile..............................             167
Activity duration (minutes) within 24 hours \b\.........             240
Number of piles per day \b\.............................               1
Strike rate (strikes per second)........................       \c\ 15 or
                                                                   25.83
------------------------------------------------------------------------
\a\ SSL reflects the combined SSLs calculated in Table 8.
\b\ ADOT anticipates that DTH could occur at one site for up to 10 hours
  (600 minutes) per day, and overlap between two sites could occur for
  up to 4 hours (240 minutes) per day. Since the potential overlap in
  sources is accounted for in the SSL adjustment, and the total
  potential duration (even with two hammers) is accounted for in the
  ``Activity duration (minutes) within 24 hours,'' the ``Number of piles
  per day'' is assumed to be 1.
\c\ 25.83 for combinations that include 8-in piles. 15 for all other
  combinations.

    Level A harassment thresholds for impulsive sound sources (impact 
pile driving and DTH) are defined for both SELcum and Peak SPL with the 
threshold that results in the largest modeled isopleth for each marine 
mammal hearing group used to establish the Level A harassment isopleth. 
In this project, Level A harassment isopleths based on SELcum were 
always larger than those based on Peak SPL (for both single hammer use 
and simultaneous use of two hammers). It should be noted that there is 
a duration component when calculating the Level A harassment isopleth 
based on SELcum, and this duration depends on the number of piles that 
would be driven in a day and strikes per pile. For some activities, 
ADOT has proposed to drive variable numbers of piles per day throughout 
the project (See ``Average Piles per Day (Range)'' in Table 1), and 
determine at the beginning of each pile driving day, the maximum number 
or duration piles would be driven that day. Here, this flexibility has 
been accounted for by modeling multiple durations for the activity, and 
determining the relevant isopleths.

     Table 13--Distances to Level A Harassment Isopleths, by Hearing Group, and Area of Level A Harassment Zones, for Single Hammer Use During Pile
                                                                Installation and Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              Level A harassment isopleth  (m)                Level A
                                                                                  -------------------------------------------------------   harassment
               Activity                     Pile           Minutes per pile or                                                             areas (km\2\)
                                         diameter(s)        strikes per pile           LF         MF         HF         PW         OW       all hearing
                                                                                                                                            groups \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation...............              30  60 minutes................          8          1         12          5          1            <0.1
                                               \b\ 24  60 minutes................          7          1         11          5          1            <0.1
                                                   20  60 minutes................          7          1         11          5          1            <0.1
Vibratory Removal....................              24  60 minutes................          7          1         11          5          1            <0.1
DTH Rock Sockets.....................              30  60 minutes................        773         28        920        414         31            <0.9
                                                       300 minutes...............      2,258         81      2,690      1,209         88            <3.5
                                                       600 minutes...............      3,584        128      4,269      1,918        140            <6.6
                                                   24  60 minutes................        359         13        427        192         15            <0.2
                                                       300 minutes...............      1,048         38      1,249        561         41            <1.4
                                                       600 minutes...............      1,664         60      1,982        891         65            <2.4
DTH Tension Anchor...................               8  120 minutes...............         82          3         98         44          4            <0.1
                                                       240 minutes...............        130          5        155         70          6            <0.1
Impact Installation..................              30  50 strikes................        100          4        119         54          4            <0.1
                                                   24  50 strikes................         54          2         65         29          3            <0.1
                                                   20  50 strikes................         54          2         65         29          3            <0.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Please refer to Table 6-4 of ADOT's IHA application for hearing group-specific areas.
\b\ Includes vibratory installation and removal.


[[Page 6004]]


  Table 14--Distances to Level A Harassment Isopleths, by Hearing Group for Simultaneous Use of Two DTH Hammers
----------------------------------------------------------------------------------------------------------------
                                                          Level A harassment isopleth (m)
      Activity combination       -------------------------------------------------------------------------------
                                        LF              MF              HF              PW              OW
----------------------------------------------------------------------------------------------------------------
8-in pile, 8-in pile............             206               7             245             110               8
8-in pile, 24-in pile...........           1,297              46           1,545             694              51
8-in pile, 30-in pile...........           2,796              99           3,329           1,496             109
24-in pile, 24-in pile..........           1,431              51           1,705             766              56
24-in pile, 30-in...............           2,268              81           2,702           1,214              88
30-in pile, 30-in pile..........           3,084             110           3,673           1,650             120
----------------------------------------------------------------------------------------------------------------

    Regarding implications for impact hammers used in combination with 
a vibratory hammer or DTH drill, the likelihood of these multiple 
sources' isopleths to completely overlap in time is slim primarily 
because impact pile driving is intermittent. Furthermore, non-
impulsive, continuous sources rely upon non-impulsive TTS/PTS 
thresholds, while impact pile driving uses impulsive thresholds, making 
it difficult to calculate isopleths that may overlap from impact 
driving and the simultaneous action of a non-impulsive continuous 
source or one with multiple strikes per second. Thus, with such slim 
potential for multiple different sources' isopleths to overlap in space 
and time, specifications should be entered as ``normal'' into the User 
Spreadsheet for each individual source separately.

Marine Mammal Occurrence and Take Calculation and Estimation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations. Additionally, we describe how the occurrence information 
is brought together to produce a quantitative take estimate for each 
phase. A summary of proposed take, including as a percentage of 
population for each of the species, is shown in Table 15.

Steller Sea Lion

    Steller sea lion abundance in the Tongass Narrows area is not well 
known. No systematic studies of Steller sea lions have been conducted 
in or near the Tongass Narrows area. Steller sea lions are known to 
occur year-round and local residents report observing Steller sea lions 
approximately once or twice per week (based on communication outlined 
in Section 6 of ADOT's IHA application). Abundance appears to increase 
during herring runs (March to May) and salmon runs (July to September). 
Group sizes may reach up to 6 to 10 individuals (Freitag 2017 as cited 
in 83 FR 37473; August 1, 2018), though groups of up to 80 individuals 
have been observed (HDR, Inc. 2003).
    ADOT conservatively estimates that one group of 10 Steller sea 
lions may be present in the project area each day, but this occurrence 
rate may as much as double (20 Steller sea lions per day) during 
periods of increased abundance associated with the herring and salmon 
runs (March to May and July to September). Therefore, ADOT anticipates 
that two large groups (20 individuals) may be taken by Level B 
harassment each day during these months. To be conservative, we assume 
all 91 days of work could be completed during these months of increased 
abundance and thus estimate 1,820 potential takes by Level B harassment 
of Steller sea lions in Tongass Narrows (i.e., 2 groups of 10 sea lions 
per day x 91 construction days = 1,820 takes by Level B harassment; 
Table 15).
    ADOT estimates that simultaneous use of two hammers (any 
combination) could occur on up to 44 days during the project. On those 
days, Level B harassment zones would extend into Clarence Strait. 
Steller sea lions are known to swim across Clarence Strait and to use 
offshore areas with deeper waters, although no estimates of at-sea 
density or abundance in Clarence Strait are available. Therefore, ADOT 
has conservatively estimated, and NMFS concurs, that during the 44 days 
with potential simultaneous use of two hammers, a group of 10 Steller 
sea lions may occur in the portion of the Level B harassment zone in 
Clarence Strait each day (one group of 10 sea lions per day x 44 days = 
440 individuals). Therefore, the preliminary sum of estimated takes by 
Level B harassment of Steller sea lions between Tongass Narrows and 
Clarence Strait is 2,260 (1,820 + 440 = 2,260 takes by Level B 
harassment).
    The largest Level A harassment zone for otariid pinnipeds could 
extend 140 m from the noise source for 10 hours of DTH using a single 
hammer, or 120 m from the noise source for 4 hours of DTH using two 
hammers for 30-in piles simultaneously. (As noted previously, ADOT 
estimates that simultaneous use of any two hammer types would occur on 
no more than 44 days). Zones for shorter durations and other activities 
would be smaller (Table 13). For some DTH activities, the estimated 
Level A harassment zone is larger than the proposed shutdown zone, and 
therefore, some Level A harassment could occur. Further, while 
unlikely, it is possible that a Steller sea lion could enter a shutdown 
zone without detection given the various obstructions along the 
shoreline, and remain in the zone long enough to be taken by Level A 
harassment before being observed and a shutdown occurring. ADOT 
therefore requests, and NMFS proposes to authorize, one take by Level A 
harassment on each of the 91 construction days (91 takes by Level A 
harassment). Take by Level B harassment proposed for authorization was 
calculated as the total calculated Steller sea lion takes by Level B 
harassment minus the takes by Level A harassment (2,260 takes-91 takes 
by Level A harassment) for a total of 2,169 takes by Level B 
harassment. Therefore, ADOT requests, and NMFS proposes to authorize, 
91 takes of Steller sea lion by Level A harassment and 2,169 takes of 
Steller sea lion by Level B harassment (2,260 total takes of Steller 
sea lion; Table 15).

Harbor Seal

    Harbor seal densities in the Tongass Narrows area are not well 
known. No systematic studies of harbor seals have been conducted in or 
near Tongass Narrows. They are known to occur year-round with little 
seasonal variation in abundance (Freitag 2017 as cited in 83 FR 37473; 
August 1, 2018) and local experts estimate that there are about 1 to 3 
harbor seals in Tongass Narrows every day, in addition to those that 
congregate near the seafood processing plants and fish hatcheries. NMFS 
has indicated that the maximum group size in Tongass Narrows is three 
individuals (83 FR 22009; May 11, 2018); however, ADOT monitoring in 
March 2021

[[Page 6005]]

observed several groups of up to 5 individuals. Based on this 
knowledge, the expected maximum group size in Tongass Narrows is five 
individuals. Harbor seals are known to be curious and may approach 
novel activity. For these reasons ADOT conservatively estimates that up 
to two groups of 5 harbor seals per group could be taken by Level B 
harassment due to project-related underwater noise each construction 
day for a total of 910 takes by Level B harassment of harbor seal in 
Tongass Narrows (i.e., 2 groups of 5 harbor seals per day x 91 
construction days = 910 total takes by Level B harassment of harbor 
seal; Table 15).
    As noted above, ADOT estimates that simultaneous use of two hammers 
(any combination) could occur on up to 44 days during the project. On 
those days, Level B harassment zones would extend into Clarence Strait. 
Harbor seals are known to swim across Clarence Strait, although no 
estimates of at-sea density or abundance in Clarence Strait are 
available. It is likely that harbor seal abundance in Clarence Strait 
is lower than in Tongass Narrows, as harbor seals generally prefer 
nearshore waters. Therefore, ADOT has conservatively estimated, and 
NMFS concurs, that during the 44 days with potential simultaneous use 
of two hammers, a group of 5 harbor seals may occur in the portion of 
the Level B harassment zone in Clarence Strait each day (one group of 5 
harbor seals per day x 44 days = 220 individuals). Therefore, the sum 
of total estimated takes by Level B harassment of harbor seals between 
Tongass Narrows and Clarence Strait is 1,130 (910 + 220 = 1,130 takes 
by Level B harassment).
    The largest Level A harassment zone for harbor seals could extend 
1,918 m from the noise source for 10 hours of DTH using a single 
hammer, or 1,640 m from the noise source for 4 hours of DTH using two 
hammers for 30-in piles simultaneously. (As noted previously, ADOT 
estimates that simultaneous use of any two hammer types would occur on 
no more than 44 days). Zones for shorter durations and other activities 
would be smaller (Table 13). Due to practicability concerns, NMFS 
proposes to require a 200 m shutdown zone for harbor seals during 24-in 
and 30-in DTH activities (Table 16). Therefore, for some DTH 
activities, the estimated Level A harassment zone is larger than the 
proposed shutdown zone, and therefore, some Level A harassment could 
occur. Harbor seals may enter and remain within the area between the 
Level A harassment zone and the shutdown zone for a duration long 
enough to be taken by Level A harassment. Additionally, while unlikely, 
it is possible that a harbor seal could enter a shutdown zone without 
detection given the various obstructions along the shoreline, and 
remain in the zone for a duration long enough to be taken by Level A 
harassment before being observed and a shutdown occurring.
    To calculate take by Level A harassment, ADOT first calculated the 
ratio of the maximum Level A harassment isopleth for 30-in DTH using a 
single hammer minus the shutdown zone isopleth (1,918 m-200 m shutdown 
zone = 1,718 m) to the Level B harassment zone isopleth (13,594 m; 
1,718 m/13,594 m = 0.1264). ADOT multiplied the resulting ratio by the 
total potential take in Tongass Narrows, resulting in 116 takes by 
Level A harassment (i.e., 910 takes by Level B harassment x 0.1264 = 
116 takes by Level A harassment). NMFS reviewed, and concurs with and 
adopts this method. (Potential operation of two DTH hammers for 24-in/
30-in or 30-in/30-in pile combinations would result in larger Level A 
harassment isopleths than 1,918 m, however, such concurrent work would 
rarely occur, if at all, and therefore, NMFS expects that calculating 
Level A harassment take using those zones would be overly conservative 
and unrealistic. Moreover, since the method used above assumes 30-inch 
DTH on all days it provided a precautionary cushion since activities 
with smaller Level A harassment zone sizes will occur on many days.) 
Take by Level B harassment proposed for authorization was calculated as 
the total calculated harbor seal takes by Level B harassment minus the 
takes by Level A harassment (1,130 takes-116 takes by Level A 
harassment) for a total of 1,014 takes by Level B harassment. ADOT 
therefore requests, and NMFS proposes to authorize, 116 takes of harbor 
seal by Level A harassment and 1,014 takes of harbor seal by Level B 
harassment (1,130 total takes of harbor seal, Table 15).

Harbor Porpoise

    Harbor porpoises are non-migratory; therefore, our occurrence 
estimates are not dependent on season. Freitag (2017 as cited in 83 FR 
37473; August 1, 2018) observed harbor porpoises in Tongass Narrows 
zero to one time per month. 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). ADOT's 2020 and 2021 monitoring program in 
Tongass Narrows did not result in sightings of this species; however, 
ADOT assumes an occurrence rate of one group per month in the following 
take estimations. For our analysis, we are considering a group to 
consist of five animals. Based on Freitag (2017), and supported by the 
reports of knowledgeable locals as described in ADOT's application, 
ADOT estimates that one group of five harbor porpoises could enter 
Tongass Narrows and potentially taken by Level B harassment due to 
project-related noise each month for a total of 15 potential harbor 
porpoise takes by Level B harassment in Tongass Narrows (i.e., 1 group 
of 5 individuals x 3 months (91 days) = 15 harbor porpoises).
    As noted above, ADOT estimates that simultaneous use of two hammers 
(any combination) could occur on up to 44 days during the project. On 
those days, the Level B harassment zone would extend into Clarence 
Strait. Harbor porpoises are known to swim across Clarence Strait and 
to use other areas of deep, open waters. Dahlheim et al. (2015) 
estimated a density of 0.02 harbor porpoises/km\2\ in an area that 
encompasses Clarence Strait. ADOT estimates, and NMFS concurs that 
during the 44 days with potential simultaneous use of two hammers, 17 
harbor porpoises (0.02 harbor porpoises/km\2\ x 18.5 km\2\ x 44 days = 
17 harbor porpoises) may occur in the portion of the Level B harassment 
zone in Clarence Strait during the project (though ADOT and NMFS 
anticipate that this is a conservative estimate, given the entire 18.5 
km\2\ area would rarely be ensonified above the Level B harassment 
threshold). Therefore, the sum of total estimated takes by Level B 
harassment of harbor porpoise between Tongass Narrows and Clarence 
Strait is 32 (15 + 17 = 32 takes by Level B harassment).
    The largest Level A harassment zone for harbor porpoises extends 
4,269 m from the noise source for 10 hours of DTH using a single 
hammer, and 3,673 m from the noise source for 4 hours of DTH using two 
hammers for 30-in piles simultaneously. (As noted previously, ADOT 
estimates that simultaneous use of any two hammer types would occur on 
no more than 44 days). Zones for shorter durations and other activities 
would be smaller (Table 13). Due to practicability concerns, NMFS 
proposes to require a 500 m shutdown zone for high frequency cetaceans 
during 24-in and 30-in DTH activities. Therefore, for some DTH 
activities, the estimated Level A harassment zone is larger than the 
proposed shutdown zone, and therefore, some Level A harassment could 
occur. Harbor porpoises may enter and remain within the area between 
the Level A harassment zone

[[Page 6006]]

and the shutdown zone for a duration long enough to be taken by Level A 
harassment. Additionally, given the large size of required shutdown 
zones for some activities and the cryptic nature of harbor porpoises, 
it is possible that a harbor porpoise could enter a shutdown zone 
without detection and remain in the zone for a duration long enough to 
be taken by Level A harassment before being observed and a shutdown 
occurring.
    To calculate take by Level A harassment, ADOT first calculated the 
ratio of the maximum Level A harassment isopleth for 30-in DTH using a 
single hammer minus the shutdown zone isopleth (4,269 m-500 m = 3,769 
m) to the Level B harassment zone isopleth (13,594 m; 3,769/13,594 = 
0.2773). ADOT multiplied the resulting ratio by the total potential 
take in Tongass Narrows, resulting in 5 takes by Level A harassment 
(i.e., 15 takes by Level B harassment x 0.2773 = 5 takes by Level A 
harassment). NMFS reviewed and concurs with this method. (Potential 
operation of two DTH hammers for 24-in/30-in or 30-in/30-in pile 
combinations would result in larger Level A harassment isopleths than 
4,269 m, however, such concurrent work would rarely occur, if at all, 
and therefore, as described above, NMFS expects that calculating Level 
A harassment take using those zones is unnecessary.) Take by Level B 
harassment proposed for authorization was calculated as the total 
calculated harbor porpoise takes by Level B harassment minus the takes 
by Level A harassment (32 takes-5 takes by Level A harassment) for a 
total of 27 takes by Level B harassment. ADOT therefore requests and 
NMFS proposes to authorize 5 takes by Level A harassment and 27 takes 
by Level B harassment (32 total takes of harbor porpoise, Table 15).

Dall's Porpoise

    Dall's porpoises are expected to only occur in the project area a 
few times per year. Their relative rarity 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. 
ADOT's monitoring program from 2020 and 2021 recorded one sighting of 6 
individuals over 23 days of observation, 16 days of observations with 
no sightings, and two sightings of 10 individuals in 14 days of 
observation; this equates to one sighting every approximately 17 days 
(DOT&PF 2020, 2021a, 2021b, 2021c, 2021d) or approximately two 
sightings per month. This species is non-migratory; therefore, the 
occurrence estimates are not dependent on season. ADOT anticipates that 
one large Dall's porpoise pod (12 individuals) may be present in the 
project area and exposed to project related underwater noise twice each 
month during 3 months of construction (91 days rounded to 3 months) for 
a total of 72 potential takes by Level B harassment in Tongass Narrows 
(i.e.,2 groups of 12 Dall's porpoises per month x 3 months = 72 
potential takes by Level B harassment).
    As noted above, ADOT estimates that simultaneous use of two hammers 
(any combination) could occur on up to 44 days during the project. On 
those days, the Level B harassment zone would extend into Clarence 
Strait, where Dall's porpoises are known to occur. Jefferson et al. 
(2019) estimated an average density of 0.19 Dall's porpoises/km\2\ in 
Southeast Alaska. ADOT estimates, and NMFS concurs, that during the 44 
days with potential simultaneous use of two hammers, 155 Dall's 
porpoises (0.19 Dall's porpoises/km\2\ x 18.5 km\2\ x 44 days = 155 
Dall's porpoises) may occur in the portion of the Level B harassment 
zone in Clarence Strait during the project (though ADOT and NMFS 
anticipate that this is a conservative estimate, given the entire 18.5 
km\2\ area would rarely be ensonified above the Level B harassment 
threshold). Therefore, the sum of total estimated takes by Level B 
harassment of harbor porpoise between Tongass Narrows and Clarence 
Strait is 227 (72 + 155 = 227 takes by Level B harassment).
    The largest Level A harassment zone for Dall's porpoises extends 
4,269 m from the noise source for 10 hours of DTH using a single 
hammer, and m from the noise source for 4 hours of DTH using two 
hammers for 30-in piles simultaneously. (As noted previously, ADOT 
estimates that simultaneous use of any two hammer types would occur on 
no more than 44 days). Zones for shorter durations and other activities 
would be smaller (Table 13). Due to practicability concerns, NMFS 
proposes to require a 500 m shutdown zone for high frequency cetaceans 
during 24-in and 30-in DTH activities. Therefore, for some DTH 
activities, the estimated Level A harassment zone is larger than the 
proposed shutdown zone, and therefore, some Level A harassment could 
occur. Dall's porpoises may enter and remain within the area between 
the Level A harassment zone and the shutdown zone and be exposed to 
sound levels for a duration long enough to be taken by Level A 
harassment. Additionally, given the large size of the required shutdown 
zones for some activities, it is possible that a Dall's porpoise could 
enter a shutdown zone without detection and remain in the zone for a 
duration long enough to taken by Level A harassment before being 
observed and a shutdown occurring.
    To calculate take by Level A harassment, ADOT first calculated the 
ratio of the maximum Level A harassment isopleth for 30-in DTH using a 
single hammer minus the shutdown zone isopleth (4,269 m-500 m = 3,769 
m) to the Level B harassment zone isopleth (13,594 m; 3,769/13,594 = 
0.2773). ADOT multiplied the resulting ratio by the total potential 
take in Tongass Narrows, resulting in 20 takes by Level A harassment 
(i.e., 72 takes by Level B harassment x 0.2773 = 20 takes by Level A 
harassment). NMFS revised and concurs with this method. (Potential 
operation of two DTH hammers for 24-in/30-in or 30-in/30-in pile 
combinations would result in larger Level A harassment isopleths than 
4,269 m, however, such concurrent work would rarely occur, if at all, 
and therefore, as described above, NMFS expects that calculating Level 
A harassment take using those zones is unnecessary.) Take by Level B 
harassment proposed for authorization was calculated as the total 
calculated Dall's porpoise takes by Level B harassment minus the takes 
by Level A harassment (227 takes-20 takes by Level A harassment) for a 
total of 207 takes by Level B harassment. ADOT therefore requests and 
NMFS proposes to authorize 20 takes by Level A harassment, and 207 
takes by Level B harassment (227 total takes of Dall's porpoise, Table 
15).

Pacific White-Sided Dolphin

    Pacific white-sided dolphins do not generally occur in the shallow, 
inland waterways of Southeast Alaska. There are no records of this 
species occurring in Tongass Narrows, and it is uncommon for 
individuals to occur in the proposed project area. However, historical 
sightings in nearby areas (Dahlheim and Towell 1994; Muto et al. 2018) 
and recent fluctuations in distribution and abundance mean it is 
possible the species could be present.
    To account for the possibility that this species could be present 
in the project area, ADOT conservatively estimates, and NMFS concurs, 
that one large group (92 individuals) of Pacific white-sided dolphins 
may be taken by Level B harassment in Tongass Narrows during the 
proposed activity.
    As noted above, ADOT estimates that simultaneous use of two hammers 
(any combination) could occur on up to 44 days during the project. On 
those days, the Level B harassment zone would

[[Page 6007]]

extend into Clarence Strait. However, no additional takes of Pacific 
white-sided dolphin are anticipated to occur due to simultaneous use of 
two hammers, given that Pacific white-sided dolphins are uncommon in 
the project area. Therefore, NMFS is proposing to authorize 92 takes by 
Level B harassment of Pacific white-sided dolphins.
    ADOT did not request, nor does NMFS propose to authorize take by 
Level A harassment for this activity given that Pacific white-sided 
dolphins are uncommon in the project area. Further, considering the 
small Level A harassment zones for mid-frequency cetaceans (Table 13 
and Table 14) in comparison to the required shutdown zones, it is 
unlikely that a Pacific white-sided dolphin would enter and remain 
within the area between the Level A harassment zone and the shutdown 
zone for a duration long enough to be taken by Level A harassment.

Killer Whale

    Killer whales are observed in Tongass Narrows irregularly with 
peaks in abundance between May and July. During 7 months of 
intermittent marine mammal monitoring (October 2020-February 2021; May-
June 2021), there were five killer whale sightings in 4 months 
(November, February, May, June) totaling 22 animals; sightings occurred 
on 5 out of 88 days of monitoring (DOT&PF 2020, 2021a, 2021b, 2021c, 
2021d). Pod sizes ranged from two to eight animals (DOT&PF 2020, 2021a, 
2021b, 2021c, 2021d). Previous incidental take authorizations in the 
Ketchikan area have estimated killer whale occurrence in Tongass 
Narrows at one pod per month, except during the peak period of May to 
July when estimates have included two pods per month (Freitag 2017 as 
cited in 83 FR 37473; August 1, 2018 and 83 FR 34134; July 17, 2019).
    As noted above, ADOT estimates that simultaneous use of two hammers 
(any combination) could occur on up to 44 days during the project. On 
those days, the Level B harassment zone would extend into Clarence 
Strait. In estimating take by Level B harassment, ADOT assumed a pod 
size of 12 killer whales, that all 91 days of work would occur between 
May and July during the peaks in abundance, and that therefore, 2 pods 
may occur within the Level B harassment zone (including both Tongass 
Narrows and Clarence Strait) during each month of work, for a total of 
72 takes by Level B harassment (2 groups x 12 individuals x 3 months = 
72 killer whales). Therefore, ADOT estimates that a total of 72 killer 
whales may be taken by Level B harassment (i.e., 2 pods of 12 
individuals per month x 3 months (91 days) = 72 takes by Level B 
harassment). NMFS reviewed and concurs with this method, and proposes 
to authorize 72 takes by Level B harassment of killer whale.
    ADOT did not request, nor does NMFS propose to authorize take by 
Level A harassment of killer whales for this activity. Considering the 
small Level A harassment zones for mid-frequency cetaceans (Table 13 
and Table 14) in comparison to the required shutdown zones, it is 
unlikely that a killer whale would enter and remain within the area 
between the Level A harassment zone and the shutdown zone for a 
duration long enough to be taken by Level A harassment.

Humpback Whale

    As discussed in the Description of Marine Mammals in the Area of 
Specified Activities section, locals have observed humpback whales an 
average of about once per week in Tongass Narrows, but there is 
evidence to suggest occurrence may be higher during some periods of the 
year. The December 19, 2019 Biological Opinion stated that based on 
observations by local experts, approximately one group of two 
individuals would occur in Tongass Narrows during ADOT's activity two 
times per seven days during pile driving, pile removal, and DTH 
activities throughout the year. The assumption was based on differences 
in abundance throughout the year, recent observations of larger groups 
of whales present during summer, and a higher than average frequency of 
occurrence in recent months (NMFS 2019). ADOT's 2020 and 2021 
monitoring program documented a similar sighting rate, with 30 humpback 
whale sightings over 53 days of in-water pile driving; some of the 
sightings were believed to be repeated sightings of the same individual 
(DOT&PF 2020, 2021a, 2021b, 2021c, 2021d). ADOT therefore predicts, and 
NMFS concurs, that one group of two individuals may occur within the 
Level B harassment zones twice per week during the proposed activities. 
As noted previously, ADOT estimates that pile driving would occur over 
the course of 91 days (13 weeks). Therefore, ADOT estimates, and NMFS 
concurs that 52 takes by Level B harassment of humpback whales (1 group 
of 2 individuals x 2 groups per week x 13 weeks = 52 takes by Level B 
harassment) from the Central North Pacific stock may occur in Tongass 
Narrows.
    As noted above, ADOT estimates that simultaneous use of two hammers 
(any combination) could occur on up to 44 days during the project. On 
those days, the Level B harassment zone would extend into Clarence 
Strait. Local specialists estimated that approximately four humpback 
whales could pass through or near the portion of the Level B harassment 
zone in Clarence Strait each day. Therefore, ADOT estimates, and NMFS 
concurs, that during the 44 days with potential simultaneous use of two 
hammers, 176 takes by Level B harassment of humpback whale could occur 
in Clarence Strait (4 humpback whales x 44 days = 176 takes by Level B 
harassment). Therefore, the sum of total estimated takes by Level B 
harassment of humpback whale between Tongass Narrows and Clarence 
Strait is 228 (52 + 176 = 228 takes by Level B harassment), and NMFS 
proposes to authorize 228 takes by Level B harassment of humpback 
whale.
    As noted previously, Wade et al. (2021) estimates that 
approximately 2 percent of all humpback whales in Southeast Alaska and 
northern British Columbia are of the Mexico DPS, while all others are 
of the Hawaii DPS. However, NMFS has conservatively assumed here that 
6.1 percent of the total humpback population in Southeast Alaska is 
from the Mexico DPS (Wade et al. 2016). Therefore, of the 228 takes of 
humpback whale proposed for authorization, NMFS expects that a total of 
14 takes would be of individuals from the Mexico DPS. NMFS expects that 
all other instances of proposed take would be from the non-listed 
Hawaii DPS.
    Take by Level A harassment of humpback whales is neither 
anticipated nor proposed to be authorized because of the expected 
effectiveness of the required monitoring and mitigation measures (see 
Proposed Mitigation section below for more details). For all pile 
driving and DTH activities, the shutdown zone exceeds the calculated 
Level A harassment zone. Humpbacks are usually readily visible, and 
therefore, we expect PSOs to be able to effectively implement the 
required shutdown measures prior to any humpback whales incurring PTS 
within Level A harassment zones.

Minke Whales

    Minke whales may be present in Tongass Narrows year-round. Their 
abundance throughout Southeast Alaska is very low, and anecdotal 
reports have not included minke whales near the project area. ADOT's 
monitoring program in Tongass Narrows also did not report any minke 
whale sightings. However, minke whales are distributed throughout a 
wide variety of habitats and could occur near the project area.

[[Page 6008]]

Minke whales are generally sighted as solo individuals (Dahlheim et al. 
2009).
    As noted above, ADOT estimates that simultaneous use of two hammers 
(any combination) could occur on up to 44 days during the project. On 
those days, the Level B harassment zone would extend into Clarence 
Strait. Based on Freitag (2017; as cited in 83 FR 37473; August 1, 2018 
and 83 FR 34134; July 17, 2019), ADOT estimates that three individual 
minke whales may occur near or within the Level B harassment zone 
(including both Tongass Narrows and Clarence Strait) every four months. 
Based on that estimated occurrence rate, NMFS estimates that three 
minke whales may occur in the Level B harassment zone during the 
proposed activities (occurring over approximately 3 months), and 
proposes to authorize 3 takes by Level B harassment of minke whales 
(Table 15).
    The largest Level A harassment zone for minke whale extends 3,584 m 
from the noise source for 10 hours of DTH using a single hammer, and 
3,084 m from the noise source for 4 hours of DTH using two hammers for 
30-in piles simultaneously. (As noted previously, ADOT estimates that 
simultaneous use of any two hammer types would occur on no more than 44 
days.) Zones for shorter durations and other activities would be 
smaller (Table 14). NMFS proposes to require a 1,500 m shutdown zone 
for minke whales during 24-in and 30-in DTH activities. Therefore, for 
some DTH activities, the estimated Level A harassment zone is larger 
than the proposed shutdown zone, and Level A harassment could occur.
    To calculate take by Level A harassment, ADOT first calculated the 
ratio of the maximum Level A harassment isopleth for 30-in DTH using a 
single hammer minus the shutdown zone isopleth (3,584 m-1,500 m = 2,084 
m) to the Level B harassment zone isopleth (13,594 m; 2,084 m/13,594 m 
= 0.1533). ADOT multiplied the resulting ratio by the total potential 
take by Level B harassment, resulting in 1 take by Level A harassment 
(i.e., 3 takes by Level B harassment x 0.1533 = 1 take by Level A 
harassment). NMFS reviewed and concurs with this method. (Potential 
operation of two DTH hammers for 24-in/30-in or 30-in/30-in pile 
combinations would result in larger Level A harassment isopleths than 
4,269 m, however, such concurrent work would rarely occur, if at all, 
and therefore, as described above NMFS expects that calculating Level A 
harassment take using those zones is unnecessary.) Take by Level B 
harassment was calculated as the total potential minke whale takes by 
Level B harassment minus the takes by Level A harassment. ADOT 
therefore requests, and NMFS proposes to authorize 1 take by Level A 
harassment and 2 takes by Level B harassment (3 total takes of minke 
whale, Table 15).

       Table 15--Proposed Amount of Take as a Percentage of Stock Abundance, by Stock and Harassment Type
----------------------------------------------------------------------------------------------------------------
                                                             Proposed authorized take
                                                 ------------------------------------------------   Percent of
            Species                 DPS/stock         Level A         Level B                          stock
                                                    harassment      harassment         Total
----------------------------------------------------------------------------------------------------------------
Steller sea lion..............  Eastern U.S.....              91           2,169           2,260             5.2
Harbor seal...................  Clarence Strait.             116           1,014           1,130             4.1
Harbor porpoise...............  Southeast Alaska               5              27              32             2.5
Dall's porpoise...............  Alaska..........              20             207             227             1.7
Pacific white-sided dolphin...  North Pacific...               0              92              92             0.3
Killer whale..................  Alaska Resident.  ..............  ..............  ..............         \a\ 3.1
                                West Coast                     0              72              72        \a\ 20.1
                                 Transient.
                                Northern          ..............  ..............  ..............        \a\ 23.8
                                 Resident.
Humpback whale................  Central North                  0             228             228         \b\ 2.3
                                 Pacific.
Minke whale...................  Alaska..........               1               2               3             N/A
----------------------------------------------------------------------------------------------------------------

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses. NMFS regulations require applicants for incidental 
take authorizations to include information about the availability and 
feasibility (economic and technological) of equipment, methods, and 
manner of conducting the activity or other means of effecting the least 
practicable adverse impact upon the affected species or stocks and 
their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    Because of the need for an ESA Section 7 consultation for effects 
of the project on ESA listed humpback whales, there are a number of 
mitigation measures that go beyond, or are in addition to, typical 
mitigation measures we would otherwise require for this sort of 
project. The proposed measures are however typical for actions in the 
Ketchikan area. The mitigation measures included herein include 
measures that align with the 2019 Biological Opinion, and are subject 
to change, as required by NMFS' ESA Section 7 consultation. If Section 
7 consultation warrants changes to these measures, NMFS expects that 
the new measures would align closely with those included in the recent 
proposed IHA for construction at the NOAA Port Facility

[[Page 6009]]

Project in Ketchikan, Alaska (86 FR 68223; December 1, 2021). ADOT must 
employ the following mitigation measures as included in the proposed 
IHA:
     Avoid direct physical interaction with marine mammals 
during construction activity. If a marine mammal comes within 10 m of 
such activity, operations must cease and vessels must reduce speed to 
the minimum level required to maintain steerage and safe working 
conditions (note that NMFS expects that a 10 m shutdown zone is 
sufficient to avoid direct physical interaction with marine mammals, 
but ADOT has conservatively proposed a 20 m shutdown zone to avoid 
physical interaction for in-water other than vessel transit);
     Ensure that construction supervisors and crews, the 
monitoring team and relevant ADOT staff are trained prior to the start 
of all pile driving and DTH activity, so that responsibilities, 
communication procedures, monitoring protocols, and operational 
procedures are clearly understood. New personnel joining during the 
project must be trained prior to commencing work;
     Pile driving activity must be halted upon observation of 
either a species for which incidental take is not authorized or a 
species for which incidental take has been authorized but the 
authorized number of takes has been met, entering or within the 
harassment zone;
     For any marine mammal species for which take by Level B 
harassment has not been requested or authorized, in-water pile 
installation/removal and DTH will shut down immediately when the 
animals are sighted;
     Employ PSOs and establish monitoring locations as 
described in the Marine Mammal Monitoring Plan and Section 5 of the 
IHA. The Holder must monitor the project area to the maximum extent 
possible based on the required number of PSOs, required monitoring 
locations, and environmental conditions. For all pile driving and 
removal at least three PSOs must be used;
     The placement of the PSOs during all pile driving and 
removal and DTH activities will ensure that the entire shutdown zone is 
visible during pile installation;
     Monitoring must take place from 30 minutes prior to 
initiation of pile driving or DTH activity (i.e., pre-clearance 
monitoring) through 30 minutes post-completion of pile driving or DTH 
activity;
     If in-water work ceases for more than 30 minutes, ADOT 
will conduct pre-clearance monitoring of both the Level B harassment 
zone and shutdown zone;
     Pre-start clearance monitoring must be conducted during 
periods of visibility sufficient for the lead PSO to determine that the 
shutdown zones indicated in Table 16 are clear of marine mammals. Pile 
driving may commence following 30 minutes of observation when the 
determination is made that the shutdown zones are clear of marine 
mammals;
     If a marine mammal is observed entering or within the 
shutdown zones indicated in Table 16, pile driving must be delayed or 
halted. If pile driving is delayed or halted due to the presence of a 
marine mammal, the activity may not commence or resume until either the 
animal has voluntarily exited and been visually confirmed beyond the 
shutdown zone (Table 16) or 15 minutes have passed without re-detection 
of the animal (30 minutes for humpback whales);
     As required by the 2019 Biological Opinion, if waters 
exceed a sea state that restricts the PSOs' ability to make 
observations within the shutdown zone, in-water pile installation and 
removal will cease. Pile installation and removal will not be initiated 
or continue until the appropriate shutdown zone is visible in its 
entirety;
     For humpback whales, if the boundaries of the harassment 
zone have not been monitored continuously during a work stoppage, the 
entire harassment zone will be surveyed again to ensure that no 
humpback whales have entered the harassment zone that were not 
previously accounted for;
     In-water activities will take place only: Between civil 
dawn and civil dusk when PSOs can effectively monitor for the presence 
of marine mammals; during conditions with a Beaufort Sea State of 4 or 
less; when the entire shutdown zone and adjacent waters are visible 
(e.g., monitoring effectiveness is not reduced due to rain, fog, snow, 
etc.). Pile driving may continue for up to 30 minutes after sunset 
during evening civil twilight, as necessary to secure a pile for safety 
prior to demobilization for the evening. PSO(s) will continue to 
observe shutdown and monitoring zones during this time. The length of 
the post- activity monitoring period may be reduced if darkness 
precludes visibility of the shutdown and monitoring zones;
     Vessel operators will implement the following required 
measures: Maintain a watch for marine mammals at all times while 
underway; remain at least and at least 91 m (100 yards (yd)) from all 
other listed marine mammals, travel at less than 5 knots (9 km/hr) when 
within 274 m (300 yd) of a whale; avoid changes in direction and speed 
when within 274 m (300 yd) of whales, unless doing so is necessary for 
maritime safety; not position vessel(s) in the path of whales, and will 
not cut in front of whales in a way or at a distance that causes the 
whales to change their direction of travel or behavior (including 
breathing/surfacing pattern); check the waters immediately adjacent to 
the vessel(s) to ensure that no whales will be injured when the 
propellers are engaged; adhere to the Alaska Humpback Whale Approach 
Regulations when transiting to and from the project site (see 50 CFR 
216.18, 223.214, and 224.103(b)); not allow lines to remain in the 
water, and not throw trash or other debris overboard, thereby reducing 
the potential for marine mammal entanglement; follow established 
transit routes and travel <10 knots while in the harassment zones; 
follow the speed limit within Tongass Narrows (7 knots for vessels over 
23 ft in length). If a whale's course and speed are such that it will 
likely cross in front of a vessel that is underway, or approach within 
91 m (100 yards (yd)) of the vessel, and if maritime conditions safely 
allow, the engine will be put in neutral and the whale will be allowed 
to pass beyond the vessel, except that vessels will remain 460 m (500 
yd) from North Pacific right whales; if a humpback whale comes within 
10 m (32.8 ft) of a vessel during construction, the vessel will reduce 
speed to the minimum level required to maintain safe steerage and 
working conditions until the humpback whale is at least 10 m (32.8 ft) 
away from the vessel; vessels are prohibited from disrupting the normal 
behavior or prior activity of a whale by any other act or omission.
     ADOT must use soft start techniques when impact pile 
driving. Soft start requires contractors to provide an initial set of 
three strikes at reduced energy, followed by a 30-second waiting 
period, then two subsequent reduced-energy strike sets. A soft start 
must be implemented at the start of each day's impact pile driving and 
at any time following cessation of impact pile driving for a period of 
30 minutes or longer; and
     If take by Level B harassment reaches the authorized limit 
for an authorized species, pile installation will be stopped as these 
species approach the Level B harassment zone to avoid additional take 
of them.
    Further, on days when simultaneous use of two hammers producing 
continuous noise (two DTH hammers, one DTH and one vibratory hammer, or 
two vibratory hammers) is expected:

[[Page 6010]]

     When combinations of one DTH hammer with a vibratory 
hammer or two DTH hammers are used simultaneously, each PSO of the two 
contractors will have three PSOs working and the PSO teams will work 
together to monitor the entire area;
     One or more PSOs will be present at each construction site 
during in-water pile installation and removal so that Level A 
harassment zones and shutdown zones are monitored by a dedicated PSO at 
all times.
     The ADOT environmental coordinator for the project will 
implement coordination between or among the PSO contractors. ADOT will 
include in the contracts that PSOs must coordinate, collaborate, and 
otherwise work together to ensure compliance with project permits and 
authorizations.
    The following specific mitigation measures will also apply to 
ADOT's in-water construction activities:
    Establishment of Level A Harassment Zones and Shutdown Zones--For 
all pile driving/removal and DTH activities, ADOT will establish a 
shutdown zone (Table 16). The purpose of a shutdown zone is generally 
to define an area within which shutdown of activity would occur upon 
sighting of a marine mammal (or in anticipation of an animal entering 
the defined area). Shutdown zones vary based on the activity type and 
duration and marine mammal hearing group (Table 16). For vibratory 
installation and removal and impact installation, shutdown zones will 
be based on the Level A harassment isopleth distances for each hearing 
group.
    ADOT anticipates that the daily duration of DTH use may vary 
significantly, with large differences in maximum zones sizes possible 
depending on the work planned for a given day. Given this uncertainty 
and concerns related to ESA-listed humpback whales, ADOT would utilize 
a tiered system to identify and monitor the appropriate Level A 
harassment zones and shutdown zones, based on the maximum expected DTH 
duration. At the start of any work involving DTH, ADOT would first 
determine whether DTH may occur at two sites concurrently or just at 
one site. If DTH may occur at two sites concurrently, then ADOT would 
implement the Level A harassment zones and shutdown zones associated 
with simultaneous DTH use of the relevant pile sizes (Table 14 and 
Table 16). If DTH may only occur at one site, ADOT would then determine 
the maximum duration of DTH possible that day (according to the defined 
duration intervals in Table 16), which would determine the appropriate 
Level A harassment isopleth for that day (Table 13 and Table 14). This 
Level A harassment zone and associated shutdown zone must be observed 
by PSO(s) for the entire work day or until it is determined that, given 
the duration of activity for the day, the Level A harassment isopleth 
cannot exceed the next lower Level A harassment isopleth size in Table 
13.
    Due to practicability concerns, shutdown zones for some species 
during some activities may be smaller than the Level A harassment 
isopleths (Table 16). The placement of PSOs during all pile driving, 
pile removal, and DTH activities (described in detail in the Proposed 
Monitoring and Reporting Section) will ensure that the entire shutdown 
zones are visible during pile installation.

                                       Table 16--Shutdown Zones and Level B Harassment Isopleths for Each Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Minutes per                                Shutdown distances (m)                                Level B
                                 Pile size      pile or    ---------------------------------------------------------------------------------  harassment
            Activity                (in)      strikes per    LF (humpback    LF (minke                                                         isopleth
                                                 pile           whales)       whales)         MF           HF           PW           OW          (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation.........         30          60 min              50                                 20                                      6,310
                                        24          60 min                                                                                         5,412
                                        20          60 min
Vibratory Removal..............         24          60 min
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH of Rock Sockets............         30          60 min             780        1,500           30          500          200           40       13,594
                                                   120 min           1,300                        50                                     50
                                                   180 min           1,700                        60                                     70
                                                   240 min           2,000                        70                                     80
                                                   300 min           2,300                        90                                     90
                                                   360 min           2,600                       100                                    100
                                                   420 min           2,900
                                                   480 min           3,100
                                                   540 min           3,400
                                                   600 min           3,600                       130                                    100
                                        24          60 min             360        1,500           20          500          200           20
                                                   120 min             570                        30                                     30
                                                   180 min             750                        30                                     30
                                                   240 min             910                        40                                     40
                                                   300 min           1,100                        40                                     50
                                                   360 min           1,200                        50                                     50
                                                   420 min           1,400                        50                                     60
                                                   480 min           1,500                        60                                     60
                                                   540 min           1,600                        60                                     70
                                                   600 min           1,700                        60                                     70
DTH of Tension Anchor..........          8         120 min              90           90           20          100           50           20
                                                   240 min             130          130                       160           70
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation............         30      50 strikes             100          100           20          120           60           20        2,154
                                        24      50 strikes              60           60                        70           30                     1,000
                                        20      50 strikes
--------------------------------------------------------------------------------------------------------------------------------------------------------


               Table 17--Shutdown Zones, by Hearing Group for Simultaneous Use of Two DTH Hammers
----------------------------------------------------------------------------------------------------------------
                                                                 Level A harassment isopleth (m)
              Activity combination              ----------------------------------------------------------------
                                                      LF           MF           HF           PW           OW
----------------------------------------------------------------------------------------------------------------
8-in pile, 8-in pile...........................          210           20          250          110           20

[[Page 6011]]

 
8-in pile, 24-in pile..........................        1,300           50          500          200           60
8-in pile, 30-in pile..........................        2,800          100                                    110
24-in pile, 24-in pile.........................        1,440           60                                     60
24-in pile, 30-in..............................        2,270           90                                     90
30-in pile, 30-in pile.........................        3,090          110                                    120
----------------------------------------------------------------------------------------------------------------

    ADOT also must abide by the terms and conditions of the December 
19, 2019 Biological Opinion and Incidental Take Statement issued by 
NMFS pursuant to section 7 of the Endangered Species Act.
    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 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 must be conducted by qualified, NMFS-approved PSOs, in 
accordance with the following:
     PSOs must be independent (i.e., not construction 
personnel) and have no other assigned tasks during monitoring periods. 
At least one PSO must have prior experience performing the duties of a 
PSO during construction activity pursuant to a NMFS-issued IHA. Other 
PSOs may substitute other relevant experience, education (degree in 
biological science or related field), or training for prior experience 
performing the duties of a PSO during construction activity pursuant to 
a NMFS-issued IHA. Where a team of three or more PSOs is required, a 
lead observer or monitoring coordinator must be designated. The lead 
observer must have prior experience performing the duties of a PSO 
during construction activity pursuant to a NMFS-issued incidental take 
authorization. PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA; and
     PSOs must record all observations of marine mammals as 
described in the Section 5 of the IHA and the Marine Mammal Monitoring 
Plan, regardless of distance from the pile being driven. PSOs shall 
document any behavioral reactions in concert with distance from piles 
being driven or removed;
    PSOs must have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary;
    Additionally, as required by NMFS' December 2019 Biological 
Opinion, each PSO will be trained and provided with reference materials 
to ensure standardized and accurate observations and data collection.
    ADOT must employ three PSOs during all pile driving and DTH. A 
minimum of one PSO (the lead PSO) must be assigned to the active pile 
driving or DTH location to monitor the shutdown zones and as much of 
the Level B harassment zones as possible. Two additional PSOs are also 
required, though the observation points may vary depending on the 
construction activity and location of the piles. To select the best 
observation locations, prior to start of construction, the lead PSO 
will stand at the construction site to monitor the Level A harassment 
zones while two or more PSOs travel in opposite directions from the 
project site along Tongass Narrows until they have reached the edge of 
the appropriate Level B harassment zone, where they will

[[Page 6012]]

identify suitable observation points from which to observe. When 
needed, an additional PSO will be stationed on the north end of Revilla 
Island observing to the northwest. See Figure 2-11 of ADOT's Marine 
Mammal Monitoring and Mitigation Plan for a map of proposed PSO 
locations. If visibility deteriorates so that the entire width of 
Tongass Narrows at the harassment zone boundary is not visible, 
additional PSOs may be positioned so that the entire width is visible, 
or work will be halted until the entire width is visible to ensure that 
any humpback whales entering or within the harassment zone are detected 
by PSOs.
    When DTH use occurs, or simultaneous use of one DTH with a 
vibratory hammer or two DTH systems occurs, creating Level B harassment 
zones that exceed 13 km and 21 km, respectively, and Level A harassment 
zones that extend over 6 km, one additional PSO will be stationed at 
the northernmost land-based location at the entrance to Tongass Narrows 
(at least two PSOs total at that location, four PSOs on duty across all 
PSO locations). One of these PSO will focus on Tongass Narrows, 
specifically watching for marine mammals that could approach or enter 
Tongass Narrows and the project area. The second PSO will look out into 
Clarence Strait, watching for marine mammals that could swim through 
the ensonified area. No additional PSOs will be required at the 
southern-most monitoring location because the Level B harassment zones 
are truncated to the southeast by islands, which prevent propagation of 
sound in that direction beyond the confines of Tongass Narrows. Takes 
by Level B harassment will be recorded by PSOs and extrapolated based 
upon the number of observed takes and the percentage of the Level B 
harassment zone that was not visible.
    Each construction contractor managing an active construction site 
and on-going in-water pile installation or removal will provide 
qualified, independent PSOs for their specific contract. The ADOT 
environmental coordinator for the project will implement coordination 
between or among the PSO contractors. It will be a required component 
of their contracts that PSOs coordinate, collaborate, and otherwise 
work together to ensure compliance with project permits and 
authorizations.

Reporting

    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities, or 60 days prior to a requested date of issuance of any 
future IHAs for projects at the same location, whichever comes first. 
The report would include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact, vibratory or DTH) and the 
total equipment duration for vibratory removal or DTH for each pile or 
hole or total number of strikes for each pile (impact driving);
     PSO locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information: Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting; Time of sighting; Identification of the 
animal(s) (e.g., genus/species, lowest possible taxonomic level, or 
unidentified), PSO confidence in identification, and the composition of 
the group if there is a mix of species; Distance and bearing of each 
marine mammal observed relative to the pile being driven for each 
sighting (if pile driving was occurring at time of sighting); Estimated 
number of animals (min/max/best estimate); Estimated number of animals 
by cohort (adults, juveniles, neonates, group composition, sex class, 
etc.); Animal's closest point of approach and estimated time spent 
within the harassment zone; Description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
     Number of marine mammals detected within the harassment 
zones and shutdown zones, by species;
     Table summarizing any incidents resulting in take of ESA-
listed species;
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting changes in behavior of the 
animal(s), if any;
     Description of other human activity within each monitoring 
period;
     Description of any deviation from initial proposal in pile 
numbers, pile types, average driving times, etc.;
     Brief description of any impediments to obtaining reliable 
observations during construction period;
     Description of any impediments to complying with these 
mitigation measures; and
     If visibility degrades to where the PSO(s) cannot view the 
entire impact or vibratory harassment zones, take of humpback whales 
would be extrapolated based on the estimated percentage of the 
monitoring zone that remains visible and the number of marine mammals 
observed.
    If no comments are received from NMFS within 30 days, the draft 
final report would constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the IHA-holder must 
immediately cease the specified activities and report the incident to 
the Office of Protected Resources (OPR) 
([email protected]), NMFS and to the Alaska Regional 
Stranding Coordinator as soon as feasible. If the death or injury was 
clearly caused by the specified activity, ADOT must immediately cease 
the specified activities until NMFS is able to review the circumstances 
of the incident and determine what, if any, additional measures are 
appropriate to ensure compliance with the terms of the IHA. The IHA-
holder must not resume their activities until notified by NMFS. The 
report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and

[[Page 6013]]

     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature 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 2 for which take could occur, given that NMFS expects the 
anticipated effects of the proposed pile driving/removal and DTH on 
different marine mammal stocks 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.
    Pile driving and DTH activities associated with the project, as 
outlined previously, have the potential to disturb or displace marine 
mammals. Specifically, the specified activities may result in take, in 
the form of Level B harassment and, for some species, Level A 
harassment from underwater sounds generated by pile driving. Potential 
takes could occur if marine mammals are present in zones ensonified 
above the thresholds for Level B harassment or Level A harassment, 
identified above, while activities are underway.
    NMFS does not anticipate that serious injury or mortality would 
occur as a result of ADOT's planned activity given the nature of the 
activity, even in the absence of required mitigation. Further, no take 
by Level A harassment is anticipated for Pacific white-sided dolphin, 
killer whale, or humpback whale, due to the likelihood of occurrence 
and/or required mitigation measures. As stated in the mitigation 
section, ADOT would implement shutdown zones that equal or exceed many 
of the Level A harassment isopleths shown in Table 13. Take by Level A 
harassment is authorized for some species (Steller sea lions, harbor 
seals, harbor porpoises, Dall's porpoises, and minke whales) to account 
for the potential that an animal could enter and remain within the area 
between a Level A harassment zone and the shutdown zone for a duration 
long enough to be taken by Level A harassment, and in some cases, to 
account for the possibility that an animal could enter a shutdown zone 
without detection given the various obstructions along the shoreline, 
and remain in the Level A harassment zone for a duration long enough to 
be taken by Level A harassment before being observed and a shutdown 
occurring. Any take by Level A harassment is expected to arise from, at 
most, a small degree of PTS because animals would need to be exposed to 
higher levels and/or longer duration than are expected to occur here in 
order to incur any more than a small degree of PTS. Additionally, and 
as noted previously, some subset of the individuals that are 
behaviorally harassed could also simultaneously incur some small degree 
of TTS for a short duration of time. Because of the small degree 
anticipated, though, any PTS or TTS potentially incurred here would not 
be expected to adversely impact individual fitness, let alone annual 
rates of recruitment or survival.
    For all species and stocks, take would occur within a limited, 
confined area (adjacent to the project site) of the stock's range. Take 
by Level A harassment and Level B harassment would be reduced to the 
level of least practicable adverse impact through use of mitigation 
measures described herein. Further the amount of take proposed to be 
authorized is small when compared to stock abundance.
    Behavioral responses of marine mammals to pile driving, pile 
removal, and DTH at the sites in Tongass Narrows are expected to be 
mild, short term, and temporary. Marine mammals within the Level B 
harassment zones may not show any visual cues they are disturbed by 
activities or they could become alert, avoid the area, leave the area, 
or display other mild responses that are not observable such as changes 
in vocalization patterns. Given that pile driving, pile removal, and 
DTH would occur for only a portion of the project's duration and often 
on nonconsecutive days, any harassment occurring would be temporary. 
Additionally, many of the species present in Tongass Narrows or 
Clarence Strait would only be present temporarily based on seasonal 
patterns or during transit between other habitats. These temporarily 
present species would be exposed to even smaller periods of noise-
generating activity, further decreasing the impacts.
    For all species except humpback whales, there are no known 
Biologically Important Areas (BIAs) near the project zone that would be 
impacted by ADOT's planned activities. For humpback whales, the whole 
of Southeast Alaska is a seasonal BIA from spring through late fall 
(Ferguson et al. 2015), however, Tongass Narrows and Clarence Strait 
are not important portions of this habitat due to development and human 
presence. Tongass Narrows is also a small passageway and represents a 
very small portion of the total available habitat. Also, while 
southeast Alaska is considered an important area for feeding humpback 
whales between March and May (Ellison et al. 2012), it is not currently 
designated as critical habitat for humpback whales (86 FR 21082; April 
21, 2021).
    More generally, there are no known calving or rookery grounds 
within the project area, but anecdotal evidence from local experts 
shows that marine mammals are more prevalent in Tongass Narrows and 
Clarence Strait during spring and summer associated with feeding on 
aggregations of fish, meaning the area may play a role in foraging. 
Because ADOT's activities could occur during any season, takes may 
occur during important feeding times. However, the project area 
represents a small portion of available foraging habitat and impacts on 
marine mammal feeding for all species, including humpback whales, 
should be minimal.
    Any impacts on marine mammal prey that would occur during ADOT's 
planned activity would have, at most, short-term effects on foraging of 
individual marine mammals, and likely no effect on the populations of 
marine mammals as a whole. Indirect effects on marine mammal prey 
during the

[[Page 6014]]

construction are expected to be minor, and these effects are unlikely 
to cause substantial effects on marine mammals at the individual level, 
with no expected effect on annual rates of recruitment or survival.
    In addition, it is unlikely that minor noise effects in a small, 
localized area of habitat would have any effect on the stocks' annual 
rates of recruitment or survival. In combination, we believe that these 
factors, as well as the available body of evidence from other similar 
activities, demonstrate that the potential effects of the specified 
activities would have only minor, short-term effects on individuals. 
The specified activities are not expected to impact rates of 
recruitment or survival and would, therefore, not result in population-
level impacts.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or proposed 
for authorization;
     Take by Level A harassment of Pacific white-sided dolphin, 
killer whale, and humpback whale is not anticipated or proposed for 
authorization;
     ADOT would implement mitigation measures including soft-
starts for impact pile driving and shutdown zones to minimize the 
numbers of marine mammals exposed to injurious levels of sound, and to 
ensure that take by Level A harassment is, at most, a small degree of 
PTS;
     The intensity of anticipated takes by Level B harassment 
is relatively low for all stocks and would not be of a duration or 
intensity expected to result in impacts on reproduction or survival;
     The only known area of specific biological importance 
covers a broad area of southeast Alaska for humpback whales, and the 
project area is a very small portion of that BIA. No other known areas 
of particular biological importance to any of the affected species or 
stocks are impacted by the activity, including ESA-designated critical 
habitat;
     The project area represents a very small portion of the 
available foraging area for all potentially impacted marine mammal 
species and stocks and anticipated habitat impacts are minor; and
     Monitoring reports from similar work in Tongass Narrows 
have documented little to no effect on individuals of the same species 
impacted by the specified activities.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The instances of take NMFS proposes to authorize is below one third 
of the estimated stock abundance for all stocks (see Table 15). The 
number of animals that we expect to authorize to be taken from these 
stocks would be considered small relative to the relevant stocks' 
abundances even if each estimated taking occurred to a new individual, 
which is an unlikely scenario. Some individuals may return multiple 
times in a day, but PSOs would count them as separate takes if they 
cannot be individually identified.
    The Alaska stock of Dall's porpoise has no official NMFS abundance 
estimate for this area, as the most recent estimate is greater than 
eight years old. The most recent estimate was 13,110 animals for just a 
portion of the stock's range. Therefore, the 227 takes of this stock 
proposed for authorization clearly represent small numbers of this 
stock.
    Likewise, the Southeast Alaska stock of harbor porpoise has no 
official NMFS abundance estimate as the most recent estimate is greater 
than eight years old. The most recent estimate was 11,146 animals (Muto 
et al. 2021) and it is highly unlikely this number has drastically 
declined. Therefore, the 32 takes of this stock proposed for 
authorization clearly represent small numbers of this stock.
    There is no current or historical estimate of the Alaska minke 
whale stock, but there are known to be over 1,000 minke whales in the 
Gulf of Alaska (Muto et al. 2018) so the 3 takes proposed for 
authorization clearly represent small numbers of this stock. 
Additionally, the range of the Alaska stock of minke whales is 
extensive, stretching from the Canadian Pacific coast to the Chukchi 
Sea, and ADOT's project area impacts a small portion of this range. 
Therefore, the 3 takes of minke whale proposed for authorization is 
small relative to estimated survey abundance, even if each proposed 
take occurred to a new individual.
    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 
Alaska 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.
    Harbor seals are the marine mammal species most regularly harvested 
for subsistence by households in Ketchikan and Saxman (a community a 
few miles south of Ketchikan, on the Tongass Narrows). Eighty harbor 
seals were harvested by Ketchikan residents in 2007, which ranked 
fourth among all communities in Alaska that year for harvest of harbor 
seals. Thirteen harbor seals were harvested by Saxman residents in 
2007. In 2008, two Steller sea lions were harvested by Ketchikan-based 
subsistence hunters, but this is the only record of sea lion harvest by 
residents of either Ketchikan or Saxman. In 2012, the community of 
Ketchikan

[[Page 6015]]

had an estimated subsistence take of 22 harbor seals and 0 Steller sea 
lion (Wolf et al. 2013). NMFS is not aware of more recent data. Hunting 
usually occurs in October and November (ADF&G 2009), but there are also 
records of relatively high harvest in May (Wolfe et al. 2013). The 
Alaska Department of Fish and Game (ADF&G) has not recorded harvest of 
cetaceans from Ketchikan or Saxman (ADF&G 2018).
    All project activities would take place within the industrial area 
of Tongass Narrows immediately adjacent to Ketchikan where subsistence 
activities do not generally occur. Both the harbor seal and the Steller 
sea lion may be temporarily displaced from the project area. The 
project also would not have an adverse impact on the availability of 
marine mammals for subsistence use at locations farther away, where 
these construction activities are not expected to take place. Some 
minor, short-term harassment of the harbor seals could occur, but given 
the information above, we would not expect such harassment to have 
effects on subsistence hunting activities.
    Based on the description of the specified activity and the proposed 
mitigation and monitoring measures, NMFS has preliminarily determined 
that there will not be an unmitigable adverse impact on subsistence 
uses from ADOT's proposed activities.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS' Office of Protected Resources (OPR) consults internally whenever 
we propose to authorize take for endangered or threatened species, in 
this case with NMFS' Alaska Regional Office (AKRO).
    NMFS OPR is proposing to authorize take of the Central North 
Pacific stock of humpback whales, of which a portion belong to the 
Mexico DPS of humpback whales, which are ESA-listed. On February 6, 
2019, NMFS AKRO completed consultation with ADOT for Tongass Narrows 
Project and issued a Biological Opinion. Reinitiation of formal 
consultation was required to analyze changes to the action that were 
not considered in the February 2019 opinion (PCTS #AKR-2018-9806/ECO 
#AKRO-2018-01287). The original opinion considered the effects of only 
one project component being constructed at a time and did not analyze 
potential effects of concurrent pile driving which may cause effects to 
the listed species that were not considered in the original opinion; 
therefore, reinitiation of formal consultation was required. NMFS' AKRO 
issued a revised Biological Opinion to NMFS' OPR on December 19, 2019 
which concluded that issuance of IHAs to ADOT is not likely to 
jeopardize the continued existence of Mexico DPS humpback whales. The 
effects of this proposed Federal action were adequately analyzed in 
NMFS' Endangered Species Act (ESA) Section 7(a)(2) Biological Opinion 
for Construction of the Tongass Narrows Project (Gravina Access), 
revised December 19, 2019, which concluded that the take NMFS proposes 
to authorize through this IHA would not jeopardize the continued 
existence of any endangered or threatened species or destroy or 
adversely modify any designated critical habitat. Because the currently 
proposed take of Mexico DPS of humpback whales exceeds that authorized 
in the 2019 Biological Opinion, NMFS will need to reinitiate 
consultation on this project.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to ADOT for the construction of four facilities in the 
channel between Gravina Island and Revillagigedo (Revilla) Island in 
Ketchikan, Alaska: The Gravina Airport Ferry Layup Facility, the 
Gravina Freight Facility, the Revilla New Ferry Berth, and the Gravina 
Island Shuttle Ferry Berth Facility in Tongass Narrows, Alaska 
beginning in March 2022, 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 
construction activities. We also request at this time comment on the 
potential Renewal of this proposed IHA as described in the paragraph 
below. Please include with your comments any supporting data or 
literature citations to help inform decisions on the request for this 
IHA or a subsequent Renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, one-year 
Renewal IHA following notice to the public providing an additional 15 
days for public comments when (1) up to another year of identical or 
nearly identical activities as described in the Description of Proposed 
Activities section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activities section of this 
notice would not be completed by the time the IHA expires and a Renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that the 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    Upon review of the request for Renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS 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: January 27, 2022.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2022-02035 Filed 2-1-22; 8:45 am]
BILLING CODE 3510-22-P