[Federal Register Volume 89, Number 131 (Tuesday, July 9, 2024)]
[Notices]
[Pages 56317-56341]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-15012]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD855]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Gary Paxton Industrial Park Vessel 
Haulout Project in Sitka, Alaska

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

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

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SUMMARY: NMFS has received a request from the City and Borough of Sitka 
(CBS) for authorization to take marine mammals incidental to the Gary 
Paxton Industrial Park Vessel Haulout Project in Sawmill Cove in Sitka, 
Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is 
requesting comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-time, 1-year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in the 
Request for Public Comments section at the end of this notice. NMFS 
will consider public comments prior to making any final decision on the 
issuance of the requested MMPA authorization and agency responses will 
be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than August 
8, 2024.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email to 
[email protected]. Electronic copies of the application and 
supporting documents, as well as a list of the references cited in this 
document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems accessing these documents, 
please call the contact listed below.
    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 https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business

[[Page 56318]]

information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Kate Fleming, Office of Protected 
Resources (OPR), NMFS, (301) 427-8401.

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 proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is 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 (NEPA)

    To comply with the NEPA of 1969 (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 NAO 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 January 18, 2024, NMFS received a request from CBS for an IHA to 
take marine mammals incidental to construction associated with the Gary 
Paxton Industrial Park Vessel Haulout Project in Sawmill Cove in Sitka, 
Alaska. Following NMFS' review of the application, CBS submitted a 
revised version on March 20, 2024, and another on April 27, 2024. The 
application was deemed adequate and complete on May 20, 2024. CBS's 
request is for take of nine species of marine mammals by Level B 
harassment and, for a subset of those species, by Level A harassment. 
Neither CBS nor NMFS expect serious injury or mortality to result from 
this activity and, therefore, an IHA is appropriate.
    NMFS previously issued an IHA to CBS for similar work (82 FR 47717, 
October 13, 2017). CBS complied with all the requirements (e.g., 
mitigation, monitoring, and reporting) of the previous IHA, and 
information regarding their monitoring results may be found in the 
Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat section.
    This proposed IHA would cover 1 year of a larger project; CBS 
intends to request a future take authorization for subsequent facets of 
the project. In year 1, construction of the following elements would be 
completed: 150-ton capacity vessel haulout piers, expanded uplands 
including stormwater collection and treatment, and a vessel washdown 
pad. The larger multi-year project involves construction of a queuing 
float, approach dock and gangway, a pile-supported deck area, vessel 
haulout ramp, an uplands shipyard, and pile anodes. While not proposed 
to be constructed as part of this project, CBS's goal is to eventually 
construct additional haulout piers to accommodate removal of vessels up 
to 300 tons.

Description of Proposed Activity

Overview

    The CBS is proposing to construct a vessel haulout facility at Gary 
Paxton Industrial Park in Sawmill Cove in Sitka, Alaska. Sitka is home 
to one of the largest fishing fleets in Alaska, but no public vessel 
haulout facility has existed in Sitka since March 2022. The project 
would enable vessels to be hauled out for maintenance, ensuring safety 
of operating fleet traffic and boosting the local economy through jobs 
and enterprise at nearby marine service providers. Over the course of 1 
year between October 2024 and September 2025, CBS would use vibratory 
and impact pile driving and vibratory removal to install and extract 
piles. These methods of pile driving would introduce underwater sounds 
that may result in take, by Levels A and B harassment, of marine 
mammals.

Dates and Duration

    The proposed IHA would be effective from October 1, 2024, to 
September 30, 2025. The project would require approximately 62 days of 
pile driving between October 15 and March 15. In-water construction 
activities would only occur during daylight hours, and typically over a 
10- to 12-hour work day.

Specific Geographic Region

    Sawmill Cove is a small body of water located near Sitka, Alaska, 
at the mouth of Silver Bay, which opens to the Sitka Sound and Gulf of 
Alaska (see figures 1 and 2 in CBS's IHA application). Sawmill Cove has 
a fairly even and shallow seafloor that gradually falls to a depth of 
approximately 40 meters (m) (131 feet (ft)). To the southeast, Silver 
Bay is approximately 0.8 kilometers (km) (0.5 miles (mi)) wide, 8.9 km 
(5.5 mi) long, and 40-85 m (131-279 ft) deep. The bay is uniform with 
few rock outcroppings or islands. To the southwest, the Eastern Channel 
opens to Sitka Sound, dropping off to depths of 120 m (400 ft) 
approximately 1.6 km (1 mi) southwest of the project site.
    Sawmill Cove is an active marine commercial and industrial area, 
which includes a multipurpose, deep-water dock constructed in 2017 to 
accommodate large vessel services, Silver Bay Seafoods' processing 
plant, a Northern Southeast Regional Aquaculture Association hatchery, 
and other tenants such as Northline Seafoods, Serka Welding and Boat 
Fabrication, and Island Fever Diving.

[[Page 56319]]

[GRAPHIC] [TIFF OMITTED] TN09JY24.008

Detailed Description of the Specified Activity

    CBS proposes to construct a vessel haulout facility within the Gary 
Paxton Industrial Park in Sawmill Cove, Sitka Alaska. Activities to be 
completed during the period of the proposed IHA include the 
construction of 150-ton capacity vessel haulout piers, expanded uplands 
including stormwater collection and treatment, and a vessel washdown 
pad. Major equipment and materials associated with construction would 
most likely be mobilized to the project site from Juneau, another 
southeast Alaska location, or Seattle, Washington. The larger multi-
year project involves construction of a queuing float, approach dock 
and gangway, a pile-supported deck area, vessel haulout ramp, an 
uplands shipyard, and pile anodes.

150-Ton Capacity Vessel Haulout Piers

    To construct the 150-ton capacity boat haulout piers, 36-inch (in) 
[91 centimeter (cm)] steel haulout pier support piles, both vertical 
and battered, would be installed primarily with a vibratory hammer (an 
American Piledriving Equipment 200-6 or comparable vibratory hammer 
from another manufacturer). Following vibratory installation, piles 
would be proofed with an impact hammer in order to achieve design 
bearing capacity (a Delmag D-62 diesel impact hammer or equivalent). Up 
to 24-in (61 cm) diameter steel temporary template pipe piles would be 
installed to facilitate accurate installation of permanent piles. 
Temporary piles would be installed and removed using a vibratory 
hammer. Temporary template piles would only be necessary for vertical 
support piles; batter piles would be installed utilizing permanent 
vertical support piles as a template. Following construction of pier 
superstructures, 24-in diameter steel fender piles would be installed 
with a vibratory hammer.

                                                Table 1--Pile Types, Installation Methods, and Durations
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                              Days of
              Pile size/type                           Method                Number of     Duration per     Strikes per    Max piles per   installation
                                                                               piles        pile (min)         pile             day         or removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Haulout Pier Support Pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in Steel Pipe Pile.....................  Vibratory Installation......              20              60             N/A               2              20
                                            Impact Installation.........                             N/A           2,000               2
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 56320]]

 
                                                                Haulout Pier Batter Pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in Steel Pipe Pile.....................  Vibratory Installation......               4             120             N/A               2              10
                                            Impact Installation.........                             N/A           3,000               2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Haulout Pier Fender Pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Pipe Pile.....................  Vibratory Installation......               6              30             N/A               4               6
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Template Pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Pipe Pile.....................  Vibratory Installation and                52              20             N/A               8              26
                                             Removal.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Expanded Uplands

    Uplands expansion would facilitate the construction of the pile-
supported 150-ton capacity haulout piers. Expanded uplands would be 
constructed with armor rock, shot rock borrow (bulk fill), and crushed 
aggregate base course. Bulk fill would be placed directly on the 
existing ground surface. When possible, materials would be placed in 
the dry during low tidal conditions, however, initial fill operations 
are planned to continue regardless of the level of tide. The bulk fill 
material would be delivered to the project site by trucks which would 
end-dump the material into on-site stockpiles for spreading. Bulk fill 
placement and spreading would be accomplished by track-mounted 
excavator, bulldozer, or motor grader. Above Mean Low Low Water, 
material would be placed in lifts of specified thickness. Each lift of 
material would be compacted with a vibratory drum roller compactor; all 
compaction operations would be performed when the tide is below the 
elevation of the work. As each lift of bulk fill material is placed, 
armor rock would be concurrently placed to protect the embankments from 
erosion during construction. As with the bulk fill materials, armor 
rock would be delivered to the project site by trucks and end-dumped 
into on-site stockpiles. Armor rock would be individually handled, 
manipulated, and placed on the bulk fill side slopes by a track-mounted 
excavator, or crane.
    A layer of base course would be placed atop the expanded uplands 
area and compacted, using similar methods to the placement of bulk fill 
materials.

Stormwater Improvements

    Stormwater improvements consisting of storm drain catch basins, 
utility holes, and associated piping would be installed to control 
stormwater within the expanded uplands. The uplands would be graded to 
facilitate stormwater drainage towards the catch basins installed in 
various locations throughout the site.

Vessel Washdown Pad and Utility Building

    A permanent vessel washdown pad would be installed adjacent to the 
expanded uplands. A heated piping system would be incorporated into the 
concrete pad and the washdown pad would be equipped with drainage for 
vessel wash water. The drainage system would collect wash water used 
for vessel cleaning in a catch basin incorporated into the washdown pad 
and send it to a storm filter system containing a grit chamber for 
filtration of the effluent. All wash water would be discharged into the 
Sitka municipal sewer.
    A 960-ft\2\ utility building would be installed on-site, adjacent 
to the vessel washdown pad, which would house the water treatment 
equipment and hydronic boilers for the heat piping system.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (see Proposed Mitigation and 
Proposed Monitoring and Reporting section).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of CBS's application summarize available 
information regarding status and trends, distribution and habitat 
preferences, and behavior and life history of the potentially affected 
species. NMFS fully considered all of this information, and we refer 
the reader to these descriptions, instead of reprinting the 
information. Additional information regarding population trends and 
threats may be found in NMFS' 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' 
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 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. 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' 
SARs). While no serious injury or mortality is anticipated or proposed 
to be authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species or stocks 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' 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' U.S. Alaska and Pacific SARs. All values presented in table 2 are 
the most recent available at the time of publication (including from 
the draft 2023 SARs) and are available online at: https://
www.fisheries.noaa.gov/

[[Page 56321]]

national/marine-mammal-protection/marine-mammal-stock-assessments.

                     Table 2--Marine Mammal Species \1\ Likely To Occur Near the Project Area That May Be Taken by CBS's Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \2\          abundance survey) \3\               SI \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                 Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray Whale......................  Eschrichtius robustus..  Eastern N Pacific......  -, -, N             26,960 (0.05, 25,849,         801        131
                                                                                                             2016).
Family Balaenopteridae (rorquals):
    Humpback Whale..................  Megaptera novaeangliae.  Hawai[revaps]i.........  -, -, N             11,278 (0.56, 7,265,          127      27.09
                                                                                                             2020).
                                                               Mexico-North Pacific...  T, D, Y             N/A (N/A, N/A, 2006)          UND       0.57
                                                                                                             \5\.
Family Delphinidae:
    Killer Whale....................  Orcinus orca...........  Eastern North Pacific    -, -, N             1,920 (N/A, 1,920,             19        1.3
                                                                Alaska Resident.                             2019) \6\.
                                                               Eastern North Pacific    -, -, N             587 (N/A, 587, 2012)          5.9        0.8
                                                                Gulf of Alaska,                              \6\.
                                                                Aleutian Islands and
                                                                Bering Sea Transient.
                                                               Eastern Northern         -, -, N             302 (N/A, 302, 2018)          2.2        0.2
                                                                Pacific Northern                             \6\.
                                                                Resident.
                                                               West Coast Transient...  -, -, N             349 (N/A, 349, 2018)          3.5        0.4
                                                                                                             \6\.
    Pacific White-Sided Dolphin.....  Lagenorhynchus           N Pacific..............  -, -, N             26,880 (N/A, N/A,             UND          0
                                       obliquidens.                                                          1990).
Family Phocoenidae (porpoises):
    Harbor Porpoise.................  Phocoena phocoena......  Yakutat/Southeast        -, -, N             N/A (N/A, N/A, 1997)          UND       22.2
                                                                Alaska Offshore Waters.                      \7\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    CA Sea Lion.....................  Zalophus californianus.  U.S....................  -, -, N             257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Northern Fur Seal...............  Callorhinus ursinus....  Eastern Pacific........  -, D, Y             626,618 (0.2, 530,376,     11,403        373
                                                                                                             2019).
    Steller Sea Lion................  Eumetopias jubatus.....  Western................  E, D, Y             49,837 (N/A, 49,837,          299        267
                                                                                                             2022) \8\.
                                                               Eastern................  -, -, N             36,308 (N/A, 36,308,        2,178       93.2
                                                                                                             2022) \9\.
Family Phocidae (earless seals):
    Harbor Seal.....................  Phoca vitulina.........  Sitka/Chatham Strait...  -, -, N             13,289 (N/A, 11,883,          356         77
                                                                                                             2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies; Committee on Taxonomy, 2022).
\2\ 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.
\3\ NMFS marine mammal SARs online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.
  CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable [explain if this is the case].
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ Abundance estimates are based upon data collected more than 8 years ago and, therefore, current estimates are considered unknown.
\6\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\7\ New stock split from Southeast Alaska stock.
\8\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
  only. The overall Nmin is 73,211 and overall PBR is 439.
\9\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
  only.

    As indicated above, all 9 species (with 14 managed stocks) in table 
2 temporally and spatially co-occur with the activity to the degree 
that take is reasonably likely to occur. All species that could 
potentially occur in the proposed project areas are included in table 1 
of the IHA application. Sperm whale, fin whale, North Pacific right 
whale, minke whale, and Dall's porpoise are other marine mammals that 
occur in the greater southeast Alaska area, but they are unlikely to be 
encountered at the Gary Paxton Industrial Park and thus are not 
addressed further in this notice.
    In addition, the northern sea otter may be found in Sawmill Cove. 
However, northern sea otter are managed by the U.S. Fish and Wildlife 
Service and are not considered further in this document.

Gray Whale

    The migration pattern of gray whales appears to follow a route 
along the western coast of Southeast Alaska, traveling northward from 
British Columbia through Hecate Strait and Dixon Entrance, passing the 
west coast of Baranof Island from late March to May and then return 
south in October and November (Jones et al., 1984; Ford et al., 2013). 
Gray whales are generally

[[Page 56322]]

solitary, traveling alone or in small groups (NMFS, 2022b).
    Historically, sightings of gray whales within Sitka Sound were 
common during the spring herring spawn; however, unusually large 
numbers of gray whales have been documented in western Sitka Sound near 
Kruzof Island since 2014 and 2015 [Alaska Department of Fish & Game 
(ADF&G), 2023; Wild et al., 2023]. It is unclear what has triggered 
this increase, but researchers believe it may be due to reduced prey 
availability in other parts of their range. Historical maps show that 
herring spawn in the eastern channel and Silver Bay in some years 
(ADF&G, 2023b). Additional historical records from 1964 to 2011 
indicate that herring spawn in the Sitka Sound vicinity approximately 
every 1-3 years (Sill and Lemons, 2019). The most recent report of 
herring spawning in Sawmill Cove that NMFS is aware of occurred in 2011 
(ADF&G, 2023b).
    Records of gray whales in the Global Biodiversity Information 
Facility (GBIF) show 69 sightings reported by the public within and 
immediately offshore of Sitka Sound in the past 20 years (GBIF, 2023a). 
Spanning from 1995 to 2000, weekly land-based surveys of marine mammals 
from Sitka's Whale Park, located at the entrance to Silver Bay, were 
completed between September and May (Straley and Pendell, 2017). Across 
190 hours of monitoring, three gray whales were observed in November. 
During recent marine mammal surveys associated with construction 
projects near the project area in Sitka Sound and in Silver Bay, no 
gray whales were sighted [Turnagain Marine Construction (TMC), 2017; 
CBS, 2019; Solstice, 2023].

Humpback Whale

    Humpback whales congregate in Sitka Sound in the spring to feed on 
spawning herring (Wild et al., 2023) and again in September through 
December to feed on more diverse forage (Straley et al., 2018; Wild et 
al., 2023). During the summer, both herring and humpback whales 
disperse throughout Sitka Sound and away from the project area 
(Straley, 2017 pers comm. in Solstice, 2017).
    During weekly surveys completed at Sitka's Whale Park between 1995 
and 2000, Humpback whales were frequently observed in groups of one to 
four at a rate of 2.18 individuals per day, with peak sightings in 
November and December (Straley and Pendell, 2017). Similar group sizes 
were documented during studies assessing the potential influence of 
humpback whales on wintering pacific herring populations, completed in 
the fall (Straley et al., 2018). Groups of 25-30 whales were 
occasionally recorded in areas outside Silver Bay in the Eastern 
Channel (Straley and Pendell, 2017). During construction of the Gary 
Paxton Industrial Park Multipurpose Dock Project in 2017, humpback 
whales were typically observed in group sizes of two (TMC, 2017. PSOs 
reported humpbacks whales most frequently between 1,800-2,000 m away, 
but distances recorded ranged from 500 m to 5,000 m (TMC, 2017).
    During monitoring in June 2019 for the O'Connell Bridge Lightering 
Float Pile Replacement Project (CBS, 2019) within Crescent Bay and the 
Eastern Channel, no humpback whales observed. Observations during the 
offshore geotechnical investigation for this project resulted in four 
sightings of nine total humpback whales during 80 hours of drilling 
operations between September 20 and 29, 2023. Sightings consisted of 
one to four whales travelling, foraging, and swimming throughout Silver 
Bay and into Herring Cove (Solstice, 2023).
    Humpback whales in the project area are predominantly of the Hawaii 
Distinct Population Segment (DPS), which is not ESA-listed. However, 
based on a comprehensive photo-identification study, individuals from 
the Mexico DPS, which is listed as threatened, are known to occur in 
Southeast Alaska. Individuals 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 of the Mexico DPS, while all others are of the 
Hawaii DPS (NMFS, 2021).

Killer Whale

    Killer whales have been observed in all oceans and seas of the 
world, but the highest densities occur in colder and more productive 
waters found at high latitudes. Killer whales are found throughout the 
North Pacific, and occur along the entire Alaska coast, in British 
Columbia and Washington inland waterways, and along the outer coasts of 
Washington, Oregon, and California.
    Of the eight recognized killer whale stocks, only the Alaska 
resident; Northern resident; Gulf of Alaska, Aleutian Islands, and 
Bering Sea Transient (Gulf of Alaska transient); and the West coast 
transient stocks are considered in this application because other 
stocks occur outside the geographic area under consideration. It is 
estimated that the majority of killer whales in the project area would 
be from the Alaska Resident stock, (60.7 percent), followed by the Gulf 
of Alaska, Aleutian Islands, and Bering Sea stock (18.6 percent), then 
the West Coast Transient (11.1 percent) and finally the Northern 
Residents stock (9.6 percent) (Young et al., 2023). The probability of 
occurrence is estimated by dividing the population of each stock by 
their combined total population.
    Records of killer whales in the GBIF show 84 sightings reported by 
the public within and immediately outside of Sitka Sound in the past 20 
years. During weekly surveys at Whale Park in Sitka between 1995 and 
2000, killer whales were ``unpredictably'' observed in groups of four 
to eight at a rate of 0.22 individuals per day, with all sightings most 
frequent in fall and spring (Straley and Pendell, 2017). During recent 
marine mammal surveys associated with construction projects near the 
project area in Sitka Sound and in Silver Bay, no killer whales were 
sighted (TMC, 2017; CBS, 2019; Solstice, 2023).

Pacific White-Sided Dolphin

    Pacific white-sided dolphins typically inhabit the open ocean and 
coastal waters away from shore (NMFS, 2022b). 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. However, there are records of pacific 
white sided dolphins observations in protected inland waters of British 
Columbia since at least the late 1980s (Morton, 2000; Ashe, 2015) It is 
thought that Pacific white-sided dolphins could be experiencing a 
poleward shift in their distribution in response to climate change 
(Salvadeo et al., 2010; Rone et al., 2017).
    During weekly surveys completed at Sitka's Whale Park between 1995 
and 2000, Pacific white sided dolphin were rarely observed in groups of 
around four at a rate of 0.02 individuals per day, with all recorded 
sightings in February (Straley and Pendell, 2017).
    Recent construction monitoring reports of monitoring in Sitka Sound 
and in Silver Bay show no occurrence of Pacific white-sided dolphins in 
the project area (TMC, 2017; CBS, 2019; Solstice, 2023).

Harbor Porpoise

    The harbor porpoise inhabits temperate, subarctic, and arctic 
waters. In the eastern North Pacific, harbor porpoises range from Point 
Barrow, Alaska, to Point Conception, California. Harbor porpoise 
primarily frequent coastal waters and occur most

[[Page 56323]]

frequently in waters less than 100 m deep (Hobbs and Waite, 2010). They 
may occasionally be found in deeper offshore waters.
    Harbor porpoise frequent nearshore waters, but are not common in 
the project vicinity. During weekly surveys completed at Sitka's Whale 
Park between 1995 and 2000, harbor porpoises were infrequently observed 
in groups of about five to eight at a rate of 0.09 individuals per day, 
with peak sightings in fall and late spring (Straley and Pendell, 
2017). During recent marine mammal surveys associated with construction 
projects near the project area in Sitka Sound and in Silver Bay, no 
harbor porpoise were sighted (TMC, 2017; CBS, 2019; Solstice, 2023).

California Sea Lion

    California sea lions live in coastal waters and on beaches, docks, 
buoys, and jetties. During the winter, male California sea lions 
commonly migrate to feeding grounds typically off California, Oregon, 
Washington, British Columbia, and recently and more rarely, in 
southeast Alaska (Woodford 2020). Females and pups typically stay close 
to breeding colonies until the pups have weened (NMFS 2022b). 
California sea lions are occasionally sighted across the Gulf of Alaska 
north to the Pribilof Islands during all seasons of the year 
(Maniscalco et al. 2004).
    No research or monitoring reports have indicated sightings of 
California Sea Lions in the project area (Straley and Pendell, 2017; 
TMC, 2017; CBS, 2019; Solstice, 2023). However, records of California 
sea lions in the GBIF show 22 sightings reported by the public within 
and immediately offshore of Sitka Sound in the past 20 years, 
suggesting a rare possibility of occurrence.

Northern Fur Seal

    Northern fur seals are typically found in offshore waters outside 
of the breeding season, although females and young males may be found 
closer to shore as they move to southern waters. In Southeast Alaska 
and British Columbia, they are known to occasionally haul out at sea 
lion rookeries (Carretta et al., 2022; Committee on Endangered Wildlife 
in Canada (COSEWIC), 2010).
    Northern fur seals are considered rare in the project area. Only 
four sightings were included GBIF records within Sitka Sound and nearby 
offshore waters in the past 20 years, largely from agency surveys 
reported in Ocean Biodiversity Information System-Spatial Ecology 
Analysis of Megavertebrate Populations (GBIF, 2023a). Additionally, 
during weekly surveys at Whale Park in Sitka between 1995 and 2000, no 
occurrences of northern fur seals were reported (Straley and Pendell, 
2017), nor were they documented during monitoring completed for recent 
construction Sitka Sound and in Silver Bay show (TMC, 2017; CBS, 2019; 
Solstice, 2023). However, a female northern fur seal pup was reported 
swimming ``erratically'' near the shore in Sitka in January 2023 before 
being transported to the Alaska Sea Life Center for medical treatment 
(McKenney, 2023).

Steller Sea Lion

    The majority of Steller sea lions that inhabit Southeast Alaska are 
part of the eastern DPS; however, branded individuals from the western 
DPS make regular movements across the 144[deg] longitude boundary to 
the northern ``mixing zone'' haulouts and rookeries within southeast 
Alaska (Jemison et al., 2013). While haulouts and rookeries in the 
northern portion of Southeast Alaska may be important areas for western 
DPS animals, there continues to be little evidence that their regular 
range extends to the southern haulouts and rookeries in Southeast 
Alaska (Jemison et al., 2018). However, genetic data analyzed in 
Hastings et al. (2020) indicated that up to 1.2 percent of Steller sea 
lions near the project area may be members of the western DPS.
    Steller sea lions are common within Sitka Sound and are likely to 
be found within the project area year-round. Steller sea lions were 
observed every month of monitoring (September to May) conducted at 
Whale Park between 1995 and 2000 (Straley and Pendell, 2017). Typical 
group sizes ranged from 1-2 (though sometimes over 100) at a rate of 
3.46 individuals per day, with peak sightings in November, January, and 
February.
    In 2017, during construction of the Gary Paxton Industrial Park 
Multipurpose Dock Project in the same area, an average of more than six 
Steller sea lions per day were observed during 22 days of in-water 
construction per day in October and November. Mean group sizes recorded 
were two individuals. During approximately 30 hours of monitoring in 
June 2019 for the O'Connell Bridge Lightering Float Pile Replacement 
Project, a total of 42 Steller sea lions were observed within Crescent 
Bay and the Eastern Channel in group sizes of 1 to 3 individuals. 
Several of these individuals were recorded as approaching or leaving 
Silver Bay (CBS, 2019). Finally, observations during the offshore 
geotechnical investigation for this project resulted in 79 sightings of 
99 total Steller sea lions during 80 hours of drilling operations 
between September 20 and 29, 2023. Sightings generally consisted of one 
to three sea lions swimming largely within Sawmill Cove (Solstice, 
2023). PSOs observed Steller sea lions at distances ranging between 30 
m to as far as 700 m from the project site, with 10 percent of 
individuals coming within less than 60 m of the project site, and over 
a third of sightings occurring between 60 m and 130 m Solstice, 2023).
    The project action area does not overlap Steller sea lion critical 
habitat. The Biorka Island haulout is the closest designated critical 
habitat and is well over 25 km southwest of the project area. There are 
no known haulouts within the project area.

Harbor Seal

    Harbor seals are common in the inside waters of southeastern 
Alaska, including within the vicinity of the project area. The species 
were observed during most months of monitoring (September through May) 
from data collected at Whale Park between 1995 and 2000, except in 
December and May (Straley and Pendell, 2017). Harbor seals were 
frequently observed in groups of one to two. Harbor seals were also 
commonly observed during recent construction projects completed in the 
area, in similar group sizes (one to two) (TMS, 2017; CBS, 2019; 
Solstice, 2023). Similar to Steller sea lions, harbor seals may linger 
in the project area for multiple days. However, no designated haulouts 
are within close proximity.

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. 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, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). 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-

[[Page 56324]]

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.

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

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al., 
2013). This division between phocid and otariid pinnipeds is now 
reflected in the updated hearing groups proposed in Southall et al. 
2019.
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take of Marine Mammals 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 of Marine Mammals 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 whether those impacts are reasonably expected to, or reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival.

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 [American National Standards Institute 
(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 and vibratory pile driving and removal. 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; National 
Institute of Occupational Safety and Health (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).
    Two types of hammers would be used on this project: impact and 
vibratory. Impact hammers operate by repeatedly dropping a heavy piston 
onto a pile to drive the pile into the substrate. Sound generated by 
impact hammers is characterized by rapid rise times and high peak 
levels, a potentially injurious combination (Hastings and Popper, 
2005). Vibratory hammers install piles by vibrating them and allowing 
the weight of the hammer to push them into the sediment. Vibratory 
hammers produce significantly less sound than impact hammers. Peak 
sound pressure levels (SPLs) may be 180 dB or greater, but are 
generally 10 to 20 dB lower than SPLs generated during impact pile 
driving of the same-sized pile (Oestman et al., 2009). Rise time is 
slower, reducing the probability and severity of injury, and sound 
energy is distributed over a greater amount of time (Nedwell and 
Edwards, 2002; Carlson et al., 2005).

[[Page 56325]]

    The likely or possible impacts of CBS'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 equipment and personnel; however, any impacts to marine 
mammals are expected to be primarily acoustic in nature. Acoustic 
stressors include effects of heavy equipment operation during pile 
installation and removal.

Acoustic Effects

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal is the means by which marine 
mammals may be harassed from CBS's specified activity. In general, 
animals exposed to natural or anthropogenic sound may experience 
behavioral, physiological, and/or physical effects, ranging in 
magnitude from none to severe (Southall et al., 2007, 2019). In 
general, exposure to pile driving noise has the potential to result in 
behavioral reactions (e.g., avoidance, temporary cessation of foraging 
and vocalizing, changes in dive behavior) and, in limited cases, an 
auditory threshold shift (TS). 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 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 (TSs) followed by behavioral 
effects and potential impacts on habitat.
    NMFS defines a noise-induced 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 TS 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 TS 
approximates PTS onset (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 
(Southall et al., 2007), a TTS of 6 dB is considered the minimum TS 
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 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.
    Many studies have examined noise-induced hearing loss in marine 
mammals (see Finneran (2015) and Southall et al. (2019) for summaries). 
TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. For 
cetaceans, published data on the onset of TTS are limited to captive 
bottlenose dolphin (Tursiops truncatus), beluga whale, harbor porpoise, 
and Yangtze finless porpoise (Neophocoena asiaeorientalis) (Southall et 
al., 2019). For pinnipeds in water, measurements of TTS are limited to 
harbor seals, elephant seals (Mirounga angustirostris), bearded seals 
(Erignathus barbatus) and California sea lions (Zalophus californianus) 
(Kastak et al., 1999, 2007; Kastelein et al., 2019b, 2019c, 2021, 
2022a, 2022b; Reichmuth et al., 2019; Sills et al., 2020). TTS was not 
observed in spotted (Phoca largha) and ringed (Pusa hispida) seals 
exposed to single airgun impulse sounds at levels matching previous 
predictions of TTS onset (Reichmuth et al., 2016). These studies 
examine hearing thresholds measured in marine mammals before and after 
exposure to intense or long-duration sound exposures. The difference 
between the pre-exposure and post-exposure thresholds can be used to 
determine the amount of threshold shift at various post-exposure times.
    The amount and onset of TTS depends on the exposure frequency.

[[Page 56326]]

Sounds at low frequencies, well below the region of best sensitivity 
for a species or hearing group, are less hazardous than those at higher 
frequencies, near the region of best sensitivity (Finneran and 
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor 
seals and harbor porpoises have a lower TTS onset than other measured 
pinniped or cetacean species (Finneran, 2015). In addition, TTS can 
accumulate across multiple exposures, but the resulting TTS will be 
less than the TTS from a single, continuous exposure with the same SEL 
(Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014, 
2015). This means that TTS predictions based on the total, cumulative 
SEL will overestimate the amount of TTS from intermittent exposures, 
such as sonars and impulsive sources. Nachtigall et al. (2018) describe 
measurements of hearing sensitivity of multiple odontocete species 
(bottlenose dolphin, harbor porpoise, beluga, and false killer whale 
(Pseudorca crassidens)) when a relatively loud sound was preceded by a 
warning sound. These captive animals were shown to reduce hearing 
sensitivity when warned of an impending intense sound. Based on these 
experimental observations of captive animals, the authors suggest that 
wild animals may dampen their hearing during prolonged exposures or if 
conditioned to anticipate intense sounds. Another study showed that 
echolocating animals (including odontocetes) might have anatomical 
specializations that might allow for conditioned hearing reduction and 
filtering of low-frequency ambient noise, including increased stiffness 
and control of middle ear structures and placement of inner ear 
structures (Ketten et al., 2021). Data available on noise-induced 
hearing loss for mysticetes are currently lacking (NMFS, 2018). 
Additionally, the existing marine mammal TTS data come from a limited 
number of individuals within these species.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several decibels above that inducing mild TTS (e.g., a 40-dB threshold 
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while 
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007, 
2019). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulsive sounds (such as 
impact pile driving pulses as received close to the source) are at 
least 6 dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level thresholds (Southall et al., 
2007, 2019). Given the higher level of sound or longer exposure 
duration necessary to cause PTS as compared with TTS, it is 
considerably less likely that PTS could occur.
    Activities for this project include impact and vibratory pile 
driving and removal. There would likely be pauses in activities 
producing the sound during each day. Given these pauses and the fact 
that many marine mammals are likely moving through the project areas 
and not remaining for extended periods of time, the potential for TS 
declines.
    Behavioral Harassment--Exposure to noise from pile driving also has 
the potential to behaviorally disturb marine mammals. Generally 
speaking, NMFS considers a behavioral disturbance that rises to the 
level of harassment under the MMPA a non-minor response--in other 
words, not every response qualifies as behavioral disturbance, and for 
responses that do, those of a higher level, or accrued across a longer 
duration, have the potential to affect foraging, reproduction, or 
survival. Behavioral disturbance may include a variety of effects, 
including subtle changes in behavior (e.g., minor or brief avoidance of 
an area or changes in vocalizations), more conspicuous changes in 
similar behavioral activities, and more sustained and/or potentially 
severe reactions, such as displacement from or abandonment of high-
quality habitat. Behavioral responses may include changing durations of 
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral 
activities (such as socializing or feeding); eliciting a visible 
startle response or aggressive behavior (such as tail/fin 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., 2004; Southall et al., 
2007, 2019; 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) and Gomez et al. (2016) for reviews of studies involving 
marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2004). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; Wartzok et al., 2004; National Research Council (NRC), 2005). 
Controlled experiments with captive marine mammals have showed 
pronounced behavioral reactions, including avoidance of loud sound 
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed 
responses of wild marine mammals to loud pulsed sound sources (e.g., 
seismic airguns) have been varied but often consist of avoidance 
behavior or other behavioral changes (Richardson et al., 1995; Morton 
and Symonds, 2002; Nowacek et al., 2007).

[[Page 56327]]

    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). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al., 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior 
may reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et 
al., 2007). For example, harbor porpoise' respiration rate increased in 
response to pile driving sounds at and above a received broadband SPL 
of 136 dB (zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike: 
127 dB re 1 [mu]Pa\2\-s) (Kastelein et al., 2013).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004), 
respectively, while North Atlantic right whales (Eubalaena glacialis) 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996; Bowers et al., 2018). The result of a flight response 
could range from brief, temporary exertion and displacement from the 
area where the signal provokes flight to, in extreme cases, marine 
mammal strandings (England et al., 2001). However, it should be noted 
that response to a perceived predator does not necessarily invoke 
flight (Ford and Reeves, 2008), and whether individuals are solitary or 
in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fishes and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a 5-day period did not cause any sleep 
deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than

[[Page 56328]]

one diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than 1 day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive (i.e., meaningful) behavioral reactions and multi-day 
anthropogenic activities. For example, just because an activity lasts 
for multiple days does not necessarily mean that individual animals are 
either exposed to activity-related stressors for multiple days or, 
further, exposed in a manner resulting in sustained multi-day 
substantive behavioral responses.
    During a dock replacement project completed at this site in 2017, 
monitors observed marine mammals during construction activities (i.e., 
vibratory or impact installation 30-in and 48-in steel piles; and 
vibratory removal of 16-in wood piles) on 22 days between October 9 and 
November 9 (TMC, 2017). In most cases behaviors were not reported, but 
there is some information to indicate that during pile driving a 
Steller sea lion was observed feeding, and humpback whales were 
observed moving through the project area to the mouth of the bay or to 
the inner bay. We expect similar behavioral responses of marine mammals 
to CBS's specified activity for this proposed project. That is, 
disturbance, if any, is likely to be temporary and localized (e.g., 
small area movements).
    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 ``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.
    Auditory Masking. Since many marine mammals rely on sound to find 
prey, moderate social interactions, and facilitate mating (Tyack, 
2008), noise from anthropogenic sound sources can interfere with these 
functions, but only if the noise spectrum overlaps with the hearing 
sensitivity of the receiving marine mammal (Southall et al., 2007; 
Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive, 
though not high-intensity, noise could cause masking at particular 
frequencies for marine mammals that utilize sound for vital biological 
functions (Clark et al., 2009). Acoustic masking is when other noises 
such as from human sources interfere 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; Erbe et al., 2016). Therefore, under certain 
circumstances, marine mammals whose acoustical sensors or environment 
are being severely masked could also be impaired from maximizing their 
performance fitness in survival and reproduction. 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 (Hotchkin and 
Parks, 2013).
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is human-made, it may be considered 
harassment when disrupting or altering critical behaviors. It is 
important to distinguish TTS and PTS, which persist after the sound 
exposure, from masking, which occurs during the sound exposure. Because 
masking (without resulting in TS) is not associated with abnormal 
physiological function, it is not considered a physiological effect, 
but rather a potential behavioral effect (though not necessarily one 
that would be associated with harassment).
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other

[[Page 56329]]

costs as animals change their vocalization behavior (e.g., Miller et 
al., 2000; Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 
2010; Holt et al., 2009). Masking can be reduced in situations where 
the signal and noise come from different directions (Richardson et al., 
1995), through amplitude modulation of the signal, or through other 
compensatory behaviors (Hotchkin and Parks, 2013). Masking can be 
tested directly in captive species (e.g., Erbe, 2008), but in wild 
populations it must be either modeled or inferred from evidence of 
masking compensation. There are few studies addressing real-world 
masking sounds likely to be experienced by marine mammals in the wild 
(e.g., Branstetter et al., 2013).
    Marine mammals at or near the proposed CBS project site may be 
exposed to anthropogenic noise which may be a source of masking. 
Vocalization changes may result from a need to compete with an increase 
in background noise and include increasing the source level, modifying 
the frequency, increasing the call repetition rate of vocalizations, or 
ceasing to vocalize in the presence of increased noise (Hotchkin and 
Parks, 2013). For example, in response to loud noise, beluga whales may 
shift the frequency of their echolocation clicks to prevent masking by 
anthropogenic noise (Tyack, 2000; Eickmeier and Vallarta, 2022).
    Masking is more likely to occur in the presence of broadband, 
relatively continuous noise sources such as vibratory pile driving. 
Energy distribution of pile driving covers a broad frequency spectrum, 
and sound from pile driving would be within the audible range of 
pinnipeds and cetaceans present in the proposed action area. While some 
construction during the CBS's activities may mask some acoustic signals 
that are relevant to the daily behavior of marine mammals, the short-
term duration and limited areas affected make it very unlikely that the 
fitness of individual marine mammals would be impacted.
    Airborne Acoustic Effects--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. Cetaceans are 
not expected to be exposed to airborne sounds that would result in 
harassment as defined under the MMPA.

Marine Mammal Habitat Effects

    The project would occur in an active marine commercial and 
industrial area. The new facility will consist primarily of new 
structures though an existing boat ramp will be filled. Construction 
activities at the Gary Paxton Industrial Park could have localized, 
temporary impacts on marine mammal habitat and their prey by increasing 
in-water SPLs 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 vibratory and impact pile driving, 
elevated levels of underwater noise would ensonify a portion of Eastern 
Channel and Silver Bay, where both fish and mammals occur and could 
affect foraging success.
    Construction activities are of short duration and would likely have 
temporary impacts on marine mammal habitat through increases in 
underwater and airborne sound. These sounds would not be detectable at 
the nearest known Steller sea lion and harbor sea haulouts, which are 
well beyond the maximum distance of predicted in-air acoustical 
disturbance.
    Water Quality--Temporary and localized reduction in water quality 
would occur as a result of in-water construction activities. Most of 
this effect would occur during the installation and removal of piles 
when bottom sediments are disturbed. The installation and removal of 
piles would disturb bottom sediments and may cause a temporary increase 
in suspended sediment in the project area. During pile removal, 
sediment attached to the pile moves vertically through the water column 
until gravitational forces cause it to slough off under its own weight. 
The small resulting sediment plume is expected to settle out of the 
water column within a few hours. Studies of the effects of turbid water 
on fish (marine mammal prey) suggest that concentrations of suspended 
sediment can reach thousands of milligrams per liter before an acute 
toxic reaction is expected (Burton, 1993).
    Effects to turbidity and sedimentation are expected to be short-
term, minor, and localized. Suspended sediments in the water column 
should dissipate and quickly return to background levels in all 
construction scenarios. Turbidity within the water column has the 
potential to reduce the level of oxygen in the water and irritate the 
gills of prey fish species in the proposed project area. However, 
turbidity plumes associated with the project would be temporary and 
localized, and fish in the proposed project area would be able to move 
away from and avoid the areas where plumes may occur. Therefore, it is 
expected that the impacts on prey fish species from turbidity, and 
therefore on marine mammals, would be minimal and temporary. In 
general, the area likely impacted by the proposed construction 
activities is relatively small compared to the available marine mammal 
habitat in Silver Bay, and does not include any areas of particular 
importance.
    In-Water Construction Effects on Potential Prey--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 and, for some, is not well documented. 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 et al., 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,

[[Page 56330]]

barotrauma (pressure-related injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses such as 
flight or avoidance are the most likely effects. 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, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). 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). More commonly, though, the impacts of noise on fish are 
temporary.
    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 greatest potential impact to fishes during construction would 
occur during impact pile installation of 24-in and 36-in steel pipe 
piles, which is estimated to occur on up to 30 days for a maximum of 
6,000 strikes per day. In-water construction activities would only 
occur during daylight hours, allowing fish to forage and transit the 
project area in the evening. Vibratory pile driving would possibly 
elicit behavioral reactions from fishes such as temporary avoidance of 
the area but is unlikely to cause injuries to fishes or have persistent 
effects on local fish populations. Construction also would have minimal 
permanent and temporary impacts on benthic invertebrate species, a 
marine mammal prey source. In addition, it should be noted that the 
area in question is low-quality habitat since it is already highly 
developed and experiences a high level of anthropogenic noise from 
normal operations and other vessel traffic. In general, any negative 
impacts on marine mammal prey species are expected to be minor and 
temporary.
    Fish populations in the proposed project area that serve as marine 
mammal prey could be temporarily affected by noise from pile 
installation and removal. The frequency range in which fishes generally 
perceive underwater sounds is 50 to 2,000 Hz, with peak sensitivities 
below 800 Hz (Popper and Hastings, 2009). Fish behavior or distribution 
may change, especially with strong and/or intermittent sounds that 
could harm fishes. High underwater SPLs have been documented to alter 
behavior, cause hearing loss, and injure or kill individual fish by 
causing serious internal injury (Hastings and Popper, 2005).
    The most likely impact to fish from pile driving activities in the 
project area would be temporary behavioral avoidance of the area. The 
duration of fish avoidance of an area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. In general, impacts to marine mammal prey 
species are expected to be minor and temporary due to the expected 
short daily duration of individual pile driving events.
    In-Water Construction Effects on Potential Foraging Habitat--The 
areas likely impacted by the project are relatively small compared to 
the available habitat in adjacent Sitka Sound and does not include any 
BIAs or ESA-designated critical habitat. The total seafloor area 
affected by pile installation and removal and the new dock footprints 
is a small area compared to the vast foraging area available to marine 
mammals in the area. Pile driving and removal at the project site would 
not obstruct long-term movements or migration of marine mammals.
    Avoidance by potential prey (i.e., fish or, in the case of 
transient killer whales, other marine mammals) of the immediate area 
due to the temporary loss of this foraging habitat is also possible. 
The duration of fish and marine mammal 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 or marine mammals of the disturbed area would still 
leave significantly large areas of fish and marine mammal foraging 
habitat in the nearby vicinity.
    In summary, given the short daily duration of sound associated with 
individual pile driving events and the relatively small areas being 
affected, pile driving activities associated with the proposed action 
are not likely to have a permanent adverse effect on any fish habitat, 
or populations of fish species. 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. 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 of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through the IHA, which will inform NMFS' 
consideration of ``small numbers,'' the negligible impact 
determinations, and impacts on subsistence uses.
    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., pile driving) has the potential to 
result in disruption of behavioral patterns for individual marine 
mammals. There is also some potential for auditory injury (Level A 
harassment) to result, primarily for mysticetes, high frequency species 
and

[[Page 56331]]

phocids because predicted auditory injury zones are larger than for 
mid-frequency species and otariids. Auditory injury is unlikely to 
occur for other groups except Steller sea lions because this species is 
expected to commonly occur in close proximity to the project area. The 
proposed mitigation and monitoring measures are expected to minimize 
the severity of the taking to the extent practicable.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the proposed take numbers are estimated.
    For acoustic impacts, 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) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential 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 estimates.

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--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 or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile 
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by TTS as, in most cases, the likelihood of 
TTS occurs at distances from the source less than those at which 
behavioral harassment is likely. TTS of a sufficient degree can 
manifest as behavioral harassment, as reduced hearing sensitivity and 
the potential reduced opportunities to detect important signals 
(conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur.
    CBS's proposed activity includes the use of continuous (vibratory 
pile driving) and impulsive (impact pile driving) sources, and 
therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa is/are 
applicable.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). CBS's 
proposed activity includes the use of impulsive (impact pile driving) 
and non-impulsive (continuous pile driving) sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                                Table 4--Thresholds Identifying the Onset of PTS
----------------------------------------------------------------------------------------------------------------
                                                     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 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1[mu]Pa\2\s. In this table, thresholds are abbreviated to reflect ANSI standards (ANSI,
  2013). However, peak sound pressure is defined by ANSI as incorporating frequency weighting, which is not the
  intent for this Technical Guidance. Hence, the subscript ``flat'' is being included to indicate peak sound
  pressure should be flat weighted or unweighted within the generalized hearing range. The subscript associated
  with cumulative sound exposure level thresholds indicates the designated marine mammal auditory weighting
  function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is
  24 hours. The cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e.,
  varying exposure levels and durations, duty cycle). When possible, it is valuable for action proponents to
  indicate the conditions under which these acoustic thresholds will be exceeded.


[[Page 56332]]

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including 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., pile driving and removal).
    The project includes vibratory pile installation and removal, and 
impact pile driving. Source levels for these activities are based on 
reviews of measurements of the same or similar types and dimensions of 
piles available in the literature. Source levels for each pile size and 
activity each year are presented in table 5. Source levels for 
vibratory installation and removal of piles of the same diameter are 
assumed to be the same.

         Table 5--Estimates of Mean Underwater Sound Levels * Generated During Vibratory and Impact Pile Installation and Vibratory Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          Pile size
           Pile driving method                       Pile type              (in.)        dB RMS      dB peak       dB SEL             Reference
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact...................................  Steel Pipe Support Pile.....           36          193          210          183  Caltrans 2015, 2020.
                                           Steel Pipe Batter Pile......
Vibratory Installation and Extraction....  Steel Pipe Support..........           36          166          N/A          N/A  NMFS 2023 Calculations.
                                           Steel Pipe Batter...........
                                           Steel Pipe Fender...........           24          163          N/A          N/A  NMFS 2023 Calculations.
                                           Steel Pipe Template.........
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.
* All sound levels are referenced at 10 m.

    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 x Log10 (R1/R2),

where

TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven 
pile, and
R2 = the distance from the driven pile of the initial 
measurement

    Absent site-specific acoustical monitoring with differing measured 
TL, a practical spreading value of 15 is used as the TL coefficient in 
the above formula. Site-specific TL data for the Sitka Sound are not 
available; therefore, the default coefficient of 15 is used to 
determine the distances to the Level A harassment and Level B 
harassment thresholds.
    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the Technical Guidance that can be used 
to relatively simply predict an isopleth distance for use in 
conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources such as pile driving, the optional User Spreadsheet 
tool predicts the distance at which, if a marine mammal remained at 
that distance for the duration of the activity, it would be expected to 
incur PTS. Inputs used in the optional User Spreadsheet tool, and the 
resulting estimated isopleths, are reported below.

                                                            Table 6--User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                     Vibratory                                        Impact
                                                         -----------------------------------------------------------------------------------------------
                                                           36-in haulout   36-in haulout   24-in haulout                   36-in haulout   36-in haulout
                                                           pier support     pier batter     pier fender   24-in template   pier support     pier batter
                                                               pile            pile            pile             pile           pile            pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           Installation                     Installation
                                                                                                              or removal           Installation
                                                         -----------------------------------------------------------------------------------------------
Spreadsheet Tab Used....................................                    A.1) Vibratory Pile Driving
                                                             E.1) Impact Pile Driving
                                                         -----------------------------------------------------------------------------------------------
Source Level (SPL)......................................              166 RMS
                                                                      163 RMS
                                                                      183 SEL
                                                         -----------------------------------------------------------------------------------------------
Transmission Loss Coefficient...........................                                                15
                                                         -----------------------------------------------------------------------------------------------
Weighting Factor Adjustment (kHz).......................                                2.5
                                                                         2
                                                         -----------------------------------------------------------------------------------------------
Activity Duration per day (minutes).....................              60             120              30              20  ..............  ..............
Number of strikes per pile..............................  ..............  ..............  ..............  ..............           2,000           3,000
                                                         -----------------------------------------------------------------------------------------------
Number of piles per day.................................                                 2                                             4               8
                                                         -----------------------------------------------------------------------------------------------
Distance of sound pressure level measurement............                                                10
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 56333]]


     Table 7--Level A Harassment and Level B Harassment Isopleths and Associated Areas From Vibratory and Impact Pile Driving and Vibratory Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Level A harassment: isopleths (m), areas (km\2\)                     Level B
                                                         --------------------------------------------------------------------------------   harassment:
          Pile size/type                   Method                                                                                          isopleth (m).
                                                                LF              MF              HF              PW              OW         areas (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Haulout Pier Support Pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in steel pipe pile.............  Vibratory              23.4, (0.006)    2.1, (0.001)   34.5, (0.009)   14.2, (0.004)    1.0, (0.001)  11,659, (9.41)
                                     Installation.
                                    Impact Installation.   2,516, (3.13)   89.5, (0.022)   2,997, (3.64)   1,347, (1.49)     98, (0.024)   1,585, (1.94)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Haulout Pier Batter Pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in Steel Pipe Pile.............  Vibratory              37.1, (0.010)    3.3, (0.003)   54.8, (0.013)   22.5, (0.006)    1.6, (0.001)  11,659, (9.41)
                                     Installation.
                                    Impact Installation.   3,297, (3.97)  117.3, (0.029)   3,928, (4.64)   1,765, (2.24)    128, (0.032)   1,585, (1.94)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Haulout Pier Fender Pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Pipe Pile.............  Vibratory              14.7, (0.004)    1.3, (0.001)   21.8, (0.006)    9.0, (0.003)    0.6, (0.001)   7,356, (7.61)
                                     Installation.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Template Pile
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Pipe Pile.............  Vibratory              17.9, (0.005)    1.6, (0.001)   26.4, (0.008)   10.9, (0.003)    0.8, (0.001)   7,356, (7.61)
                                     Installation and
                                     Removal.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations.
    Additionally, we describe how the occurrence information is 
synthesized to produce a quantitative estimate of the take that is 
reasonably likely to occur and proposed for authorization. Available 
information regarding marine mammal occurrence in the vicinity of the 
project area includes site-specific and nearby survey information and 
historic data sets. Prior data sets consulted included: (1) Protected 
Species Observer (PSO) monitoring completed at the project site on 8 
days between September 20 and 29, 2023 during the geotechnical 
investigation preceding this project (Solstice, 2023), (2) PSO 
monitoring completed at the project site on 22 days between October and 
November 2017 during the Multipurpose Dock Project (TMC, 2017), (3) PSO 
monitoring completed at O'Connell Bridge (approximately 7 km to the 
east of the project site) on 4 days in June 2019 (CBS, 2019); (4) Land-
based surveys conducted at Sitka's Whale Park completed weekly between 
September and May 1995-2000 (Straley and Pendell (2017)); and, (5) data 
available on the GBIF (see IHA application for further details).
    To estimate take, CBS referred to the above referenced data sets to 
estimate takes per day for each species and multiplied this factor by 
the total number of construction days. NMFS finds it more appropriate 
to describe the take estimate inputs according to a daily occurrence 
probability in which groups per day and group size are estimated for 
each species and multiplied by the number of days of each type of pile 
driving activity. The equation used to estimate take by Level B 
harassment for all species is:

Exposure Estimate = group size x groups per day x days of pile driving 
activity.

    CBS proposes to implement shutdown zones for mid-frequency 
cetaceans and otariids (except Steller sea lions) that meet or exceed 
the Level A harassment isopleths for all activities. For phocids, high 
frequency cetaceans, and low-frequency cetaceans, the calculated Level 
A harassment zones exceed the proposed shutdown zones during impact 
installation of 36-in steel piles, planned to occur on 30 construction 
days. Because the best available abundance estimates for these species 
cover the general region of Sitka Sound and Silver Bay, estimates of 
take by Level A harassment were based on the maximum predicted Level B 
isopleth for each pile type, typically from vibratory pile driving. In 
the absence of density data, best available monitoring data for the 
general area were used to estimate take by Level A harassment. 
Specifically, to calculate estimated take by Level A harassment for 
these species, we proportionally compared, by hearing group, the 
portion of the largest Level A harassment area (km\2\) that exceeds the 
planned shutdown zone area (km\2\) to the area (km\2\) of the largest 
Level B harassment zone across that pile type (typically from vibratory 
pile driving). This ratio was then multiplied by the group size, daily 
sightings, and number of construction days, according to the following 
equation:

Take by Level A harassment = Level A harassment area (km\2\)/Level B 
harassment area (km\2\) x group size x groups per day x days of pile 
driving.

    For Steller sea lions, during impact pile driving of 24-in and 36-
in steel pipe piles, the shutdown zone would be established at 60 m 
rather than the larger Level A harassment isopleths (100 m and 130 m, 
respectively) due to practicability; local monitoring data suggests 
that Steller sea lions frequently occur within close proximity of the 
project site. The method described above did not produce an estimate of 
take by Level A harassment consistent with the best available data for 
this species at the project location. Therefore, recent monitoring data 
collected at this site (Solstice, 2023), were used as the basis of 
calculating take by Level A harassment. The proportion of Steller sea 
lions detected between 60 m and 130 m was multiplied by group size, 
number of daily sightings, and multiplied by the number of construction 
days when impact pile driving is proposed according to this equation:

Take by Level A harassment = group size x groups per day x days of 
impact pile driving activity x proportion of Steller sea lions observed 
occurring between 60-130 m during geotechnical drilling.

    Proposed take estimates were rounded up to the nearest whole number 
in table 8.
Gray Whale
    CBS requested take by Level B harassment of 31 gray whales, based 
on an estimated 1 gray whale every 2 days for 62 construction days. 
However,

[[Page 56334]]

during weekly surveys conducted from September to May between 1995 and 
2000, gray whales were infrequently observed in groups of three from 
Whale Park. As such, NMFS finds it more appropriate to propose to 
authorize 1 group of 3 gray whales every 14 construction days (62/14 
construction days = 4.4 2-week construction week periods), resulting in 
14 takes by Level B harassment (1 group x 3 gray whales x 4.4 
construction periods = 13.2 takes by Level B harassment).
    The proposed shutdown zone exceeds the calculated Level A 
harassment zone except during impact pile driving of 36-in steel piles 
(support and battered), estimated across 30 construction days. As such, 
it is possible that gray whales may occur in the Level A harassment 
zone and stay long enough to incur PTS before exiting. For 36-in 
support piles, the ratio of the Level A harassment area (km\2\) that 
exceeds the shutdown zone to the maximum predicted Level B harassment 
area (km\2\) is 0.06. This activity is estimated to take place on 20 
construction days. For 36-in batter piles, the ratio of the Level A 
harassment area (km\2\) that exceeds the shutdown zone to the Level B 
harassment area is 0.16. This activity is estimated to take place on 10 
construction days. As such, 3 takes by Level A harassment are estimated 
[(0.06 x 4.4 construction periods x 1 group x 3 gray whales) + (0.16 x 
4.4 construction periods x 1 group x 3 gray whales) = 2.9 takes by 
Level A harassment].
    Any individuals exposed to the higher levels associated with the 
potential for PTS closer to the source might also be behaviorally 
disturbed, however, for the purposes of quantifying take we do not 
count those exposures of one individual as a take by both Level A 
harassment take and Level B harassment. Therefore, takes by Level B 
harassment calculated as described above were further modified to 
deduct the proposed amount of take by Level A harassment. Therefore, 
NMFS proposes to authorize 3 takes by Level A harassment and 11 takes 
by Level B harassment for gray whale, for a total of 14 takes. When 
allocating take across stocks, take estimates are rounded up to the 
nearest whole number.
Humpback Whale
    CBS requested take by Level B harassment of 248 humpback whales, 
based on an estimated 4 humpback whales occurring every 1 construction 
day for 62 construction days. NMFS concurs with this take estimate, 
acknowledging that two groups of two humpback whales occurring each 
construction day is reasonable based on previous monitoring data (2 
groups x 2 humpback whales x 62 construction days = 248 takes by Level 
B harassment of humpback whale).
    The proposed shutdown zone exceeds the calculated Level A 
harassment zone except during impact pile driving of 36-in steel piles 
(support and battered), estimated across 30 construction days. As such, 
it is possible that humpback whales may occur in the Level A harassment 
zone and stay long enough to incur PTS before exiting. For 36-in 
support piles, the ratio of the Level A harassment area (km\2\) that 
exceeds the shutdown zone to the maximum predicted Level B harassment 
area (km\2\) is 0.06. This activity is estimated to take place on 20 
construction days. For 36-in batter piles, the ratio of the Level A 
harassment area (km\2\) that exceeds the shutdown zone to the Level B 
harassment area is 0.16. This activity is estimated to take place on 10 
construction days. As such, 12 takes by Level A harassment are 
estimated [(0.06 x 20 construction days x 2 groups x 2 humpback whales) 
+ (0.16 x 10 construction days x 2 groups x 2 humpback whales) = 11.2 
takes by Level A harassment].
    Any individuals exposed to the higher levels associated with the 
potential for PTS closer to the source might also be behaviorally 
disturbed, however, for the purposes of quantifying take we do not 
count those exposures of one individual as a take by both Level A 
harassment take and Level B harassment. Therefore, takes by Level B 
harassment calculated as described above were further modified to 
deduct the proposed amount of take by Level A harassment. Therefore, 
NMFS proposes to authorize 12 takes by Level A harassment and 236 takes 
by Level B harassment for humpback whale, for a total of 248 takes. 
When allocating take across stocks, take estimates are rounded up to 
the nearest whole number.
Killer Whale
    CBS requested take by Level B harassment of 32 killer whales, based 
on an estimated 1 killer whale occurring every 2 construction days for 
62 construction days. However, because killer whales were unpredictably 
observed from Whale Park in groups of 4-8 during weekly surveys 
conducted from September to May between 1995 and 2000, NMFS finds it 
more appropriate to propose to authorize 1 group of 8 killer whales 
every 7 construction days (62/7 construction days = 8.9 construction 
weeks), resulting in 71 takes by Level B harassment (1 group x 8 killer 
whales x 8.9 construction weeks = 71 takes by Level B harassment). No 
takes by Level A harassment were requested or are proposed for 
authorization.
Pacific White-Sided Dolphin
    CBS requested take by Level B harassment of 16 Pacific white-sided 
dolphin, based on an estimated 1 Pacific white-sided dolphin occurring 
every 4 construction days for 62 construction days. However, Pacific 
white-sided dolphin were rarely observed from Whale Park in groups of 
four during weekly surveys conducted from September to May between 1995 
and 2000. As such, NMFS finds it more appropriate to propose to 
authorize 1 group of 4 Pacific white-sided dolphin every 14 
construction days (62/14 = 4.4 2-week construction periods), resulting 
in 18 takes by Level B harassment (1 group x 4 Pacific white-sided 
dolphin x construction 4.4 periods = 17.6 takes by Level B harassment). 
No takes by Level A harassment are requested or proposed for 
authorization.
Harbor Porpoise
    CBS requested take by Level B harassment of 16 harbor porpoise, 
based on an estimated 1 harbor porpoise occurring every 4 construction 
days for 62 construction days. However, harbor porpoise were rarely 
observed from Whale Park in groups of five during weekly surveys 
conducted from September to May between 1995 and 2000. As such, NMFS 
finds it more appropriate to propose to authorize 1 group of 5 harbor 
porpoise every 14 construction days (62/14 construction days = 4.4 2-
week construction week periods), resulting in 22 takes by Level B 
harassment (1 group x 5 harbor porpoises x 4.4 construction periods = 
22 takes by Level B harassment).
    During impact pile driving of 36-in steel piles, estimated across 
30 construction days, the expected Level A harassment zone is larger 
than the planned shutdown zone (see Figure 1 of the Marine Mammal 
Mitigation and Monitoring Plan). As such, it is possible that harbor 
porpoise may enter the Level A harassment zone and stay long enough to 
incur PTS before exiting. For 36-in support piles, the ratio of the 
Level A harassment area (km\2\) that exceeds the shutdown zone to the 
maximum predicted Level B harassment area (km\2\) is 0.38. This 
activity is estimated to take place on 20 construction days (20 
construction days/14 days = 1.43 2-week construction periods). For 36-
in batter piles, the ratio of the portion of the Level A harassment 
area that exceeds the shutdown zone area (km\2\) to the maximum 
predicted Level B harassment

[[Page 56335]]

area is 0.48. This activity is estimated to take place on 10 
construction days (10 construction days/14 days = 0.71 2-week 
construction periods). As such, five takes by Level A harassment are 
estimated [(0.38 x 1 group x 5 harbor porpoise x 1.43 2-week 
construction periods) + (0.48 x 1 group x 5 harbor porpoises x 0.71 2-
week construction periods) = 4.4 takes by Level A harassment].
    Any individuals exposed to the higher levels associated with the 
potential for PTS closer to the source might also be behaviorally 
disturbed; however, for the purposes of quantifying take we do not 
count those exposures of one individual as a take by both Level A 
harassment and Level B harassment. Therefore, NMFS proposes to 
authorize 5 takes by Level A harassment and 17 takes by Level B 
harassment for harbor porpoise, for a total of 22 takes.
Steller Sea Lion
    CBS requested take by Level B harassment of 496 Steller sea lions, 
based on an estimated 8 Steller sea lions occurring every 1 
construction day for 62 construction days. NMFS concurs with this take 
estimate, acknowledging that four groups of two Steller sea lions 
occurring each construction day is reasonable based on previous 
monitoring data (2 groups x 4 Steller sea lion x 62 construction days = 
496 takes by Level B harassment of Steller sea lion).
    During impact pile driving of 36-in steel piles, estimated across 
30 construction days, the expected Level A harassment zone is larger 
than the proposed shutdown zone. As such, it is possible that Steller 
sea lion may enter the Level A harassment zone and stay long enough to 
incur PTS before exiting. For 36-in support piles, the ratio of the 
Level A harassment area that exceeds the planned shutdown zone (km\2\) 
to the maximum predicted Level B harassment area (km\2\) for is 0.001. 
This activity is estimated to take place on 20 construction days. For 
36-in batter piles, the ratio of the Level A harassment area (km\2\) to 
the maximum predicted Level B harassment area is 0.002. This activity 
is estimated to take place on 10 construction days. As such, one take 
by Level A harassment was estimated [(0.001 x 20 construction days x 2 
groups x 4 Steller sea lion x 20 construction days) + (0.002 x 10 
construction days x 2 groups x 4 Steller sea lion x 10 construction 
days) = 0.32 takes by Level A harassment].
    However, the 0.32 takes by Level A harassment estimated using the 
method described above does not likely reflect the occurrence of 
Steller sea lion in the project area. Based on monitoring data 
collected during geotechnical survey conducted to inform this IHA 
application, Steller sea lions are expected to disproportionally occur 
within close proximity to the project site. Approximately 37 percent of 
Steller sea lions documented during that survey were observed between 
60 m and 130 m, which corresponds to the Level A zones during impact 
pile driving of 36-in piles. These scenarios may occur on up to 30 
construction days. Therefore 89 additional takes by Level A harassment 
are proposed for authorization (2 groups of 4 Steller sea lion x 30 
construction days x 0.37 = 89 takes by Level A harassment).
    Any individuals exposed to the higher levels associated with the 
potential for PTS closer to the source might also be behaviorally 
disturbed, however, for the purposes of quantifying take we do not 
count those exposures of one individual as a take by both Level A and 
Level B harassment. Therefore takes by Level B harassment calculated as 
described above are further modified to deduct the proposed amount of 
take by Level A harassment. Therefore, NMFS proposes to authorize 89 
takes by Level A harassment and 407 takes by Level B harassment for 
Steller sea lion, for a total of 496 takes.
California Sea Lion
    CBS requested take by Level B harassment of five California sea 
lions, based on an estimated one California sea lion occurring every 
month that construction is planned (October to March = 5 months) to 
account for the unlikely but small possibility that California sea lion 
could occur in the project area. However, NMFS finds it more 
appropriate to estimate take by Level B harassment according to 
proposed duration of in-water work (62 construction days/30 days in 1 
month = 2.06 construction months). As such, NMFS proposes to authorize 
take by Level B harassment of three California sea lion (1 group x 1 
California sea lion x 2.06 construction months = 2.06 takes by Level B 
harassment of California sea lion). No takes by Level A harassment are 
requested or proposed for authorization.
Northern Fur Seal
    CBS requested take by Level B harassment of five northern fur 
seals, based on an estimated one northern fur seal occurring every 
month that construction is planned (October--March = 5 months) to 
account for the unlikely but small possibility that northern fur seals 
could occur in the project area. However, NMFS finds it more 
appropriate to estimate take by Level B harassment according to 
proposed duration of in-water work (62 construction days/30 days in 1 
month = 2.06 months). As such, NMFS proposes to authorize take by Level 
B harassment of three northern fur seals (1 group x 1 northern fur seal 
x 2.06 construction months = 2.06 takes by Level B harassment of 
northern fur seal). No takes by Level A harassment are requested or 
proposed for authorization.
Harbor Seal
    CBS requested take by Level B harassment of 124 harbor seals, based 
on an estimated 2 harbor seals occurring every 2 construction days for 
62 construction days. However, because harbor seals are frequently 
documented in the project area, NMFS finds it more appropriate to 
propose to authorize 186 takes by Level B harassment of harbor seal, 
based on the maximum groups size of 3 documented at the project site in 
2017 (1 group x 3 harbor seal x 62 construction days = 186 takes by 
Level B harassment).
    During impact pile driving of 36-in steel piles, estimated across 
30 construction days, the expected Level A harassment zone is larger 
than the planned shutdown zone. As such, it is possible that harbor 
seal may enter the Level A harassment zone and stay long enough to 
incur PTS before exiting. For 36-in support piles, the ratio of the 
Level A harassment area (km\2\) that exceeds the planned shutdown zone 
to the Level B harassment area (km\2\) is 0.16. This activity is 
estimated to take place on 20 construction days. For 36-in batter 
piles, the ratio of the Level A harassment area that exceeds the 
shutdown zone area (km\2\) to the maximum predicted Level B harassment 
area is 0.23 (km\2\). This activity is estimated to take place on 10 
construction days. As such, 34 takes by Level A harassment are 
estimated [(0.16 x 20 construction days x 1 group x 3 harbor seals x 20 
construction days) + (0.23 x 10 construction days x 1 group x 3 harbor 
seals) = 33.2 takes by Level A harassment].
    Any individuals exposed to the higher levels associated with the 
potential for PTS closer to the source might also be behaviorally 
disturbed, however, for the purposes of quantifying take we do not 
count those exposures of one individual as a take by both Level A 
harassment take and Level B harassment. Therefore takes by Level B 
harassment calculated as described above are further modified to deduct 
the proposed amount of take by Level A harassment. Therefore, NMFS 
proposes to authorize 34 takes by Level A harassment and 152 takes by

[[Page 56336]]

Level B harassment for harbor seal, for a total of 186 takes.
    The total proposed take authorization for all species is summarized 
in table 8 below. Take by Level A harassment is proposed for a total of 
3 incidents for gray whale, 11 incidents for humpback whale, 5 
incidents for harbor porpoise, 6 instances for Steller sea lion, and 34 
incidents for harbor seal.

           Table 8--Proposed Take by Stock and Harassment Type and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
                                                                   Proposed authorized take \1\    Proposed take
                                                                 --------------------------------      as a
                Species                           Stock                                            percentage of
                                                                      Level B         Level A          stock
                                                                    harassment      harassment       abundance
----------------------------------------------------------------------------------------------------------------
Gray Whale............................  Eastern N Pacific.......              11               3              <1
                                        Mexico--North Pacific...               5               1              <1
Humpback Whale \2\....................  Hawai[revaps]i..........             231              11              <1
Killer Whale \3\......................  ENP Alaska Resident.....              44               0             2.3
                                        ENP Northern Resident...               7               0            14.2
                                        ENP Gulf of Alaska,                   14               0             2.4
                                         Aleutian Islands, and
                                         Bering Sea.
                                        West Coast Transient....               8               0             2.3
Pacific white-sided dolphin...........  North Pacific...........              18               0              <1
Harbor Porpoise.......................  Yakutat/Southeast Alaska              17               5           (\4\)
                                         Offshore Waters.
Steller sea lion \5\..................  Western DPS.............               5               1              <1
                                        Eastern DPS.............             402              88             1.3
California sea lion...................  United States...........               3               0              <1
Northern fur seal.....................  Eastern Pacific.........               3               0              <1
Harbor Seal...........................  Sitka/Chatham Strait....             152              34             1.4
----------------------------------------------------------------------------------------------------------------
\1\ When allocating take across stocks, take estimates are rounded up to the nearest whole number.
\2\ 2 percent of take by Level A and Level B harassment of humpback whales are allocated to the Mexico DPS
  according to NMFS, 2021
\3\ Take by level B harassment of killer whale is allocated across stocks according to the proportion of the
  stock compared to total number of animals in all four stocks that could occur in the project area: Alaska
  Residents, 60.7 percent; Northern Residents, 9.6 percent; Gulf of Alaska, Aleutian Islands, and Bering Sea:
  18.6 percent; West Coast Transient, 11.1 percent.
\4\ A reliable abundance estimate for this stock is currently unavailable.
\5\ 1.2 percent take by Level A and Level B harassment of Steller sea lions are allocated to the Western DPS
  according to Hastings et al. (2020).

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 (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting 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, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat, as 
well as subsistence uses. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the likelihood that the measure will be effective if 
implemented (probability of accomplishing the mitigating result if 
implemented as planned), the likelihood of effective implementation 
(probability implemented as planned); and,
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, and impact on 
operations.

Mitigation for Marine Mammals and Their Habitat

    Shutdown Zones--For all pile driving activities, CBS proposes to 
implement shutdowns within designated zones. The purpose of a shutdown 
zone is generally to define an area within which shutdown of the 
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 marine mammal hearing group (table 
9). In most cases, the shutdown zones are based on the estimated Level 
A harassment isopleth distances for each hearing group. However, in 
cases where it would be challenging to detect marine mammals at the 
Level A harassment isopleth (e.g., for phocids, high frequency 
cetaceans, and low frequency cetaceans during impact pile driving) and/
or frequent shutdowns would create practicability concerns (e.g., 
Steller sea lions during impact pile driving), smaller shutdown zones 
have been proposed (table 9).
    Construction supervisors and crews, Protected Species Observers 
(PSOs), and relevant CBS staff must 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, as necessary to avoid direct physical 
interaction. If an activity 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 indicated in table 9, or 15 minutes have passed 
without re-detection of the animal.
    Finally, construction activities must be halted upon observation of 
a species for which incidental take is not

[[Page 56337]]

authorized or a species for which incidental take has been authorized 
but the authorized number of takes has been met entering or within any 
harassment zone. If a marine mammal species not covered under this IHA 
enters a harassment zone, all in-water activities will cease until the 
animal leaves the zone or has not been observed for at least 15 
minutes, and NMFS would be notified about species and precautions 
taken. Pile driving will proceed if the unauthorized species is 
observed leaving the harassment zone or if 15 minutes have passed since 
the last observation.

                                        Table 9--Proposed Shutdown Zones
----------------------------------------------------------------------------------------------------------------
                                                                       Shutdown zones (m)
                                               -----------------------------------------------------------------
                                                                                                     OW
        Pile size/type              Method                                                 ---------------------
                                                    LF         MF         HF         PW      Steller
                                                                                             sea lion   Other OW
----------------------------------------------------------------------------------------------------------------
                                            Haulout Pier Support Pile
----------------------------------------------------------------------------------------------------------------
36-in Steel Pipe Pile........  Vibratory               30         10         40         20         10         10
                                Installation.
                               Impact               2,000         90        300        130         60        100
                                Installation.
----------------------------------------------------------------------------------------------------------------
                                            Haulout Pier Batter Pile
----------------------------------------------------------------------------------------------------------------
36-in Steel Pipe Pile........  Vibratory               40         10         60         30         10         10
                                Installation.
                               Impact               2,000        120        300        130         60        130
                                Installation.
----------------------------------------------------------------------------------------------------------------
                                            Haulout Pier Fender Pile
----------------------------------------------------------------------------------------------------------------
24-in Steel Pipe Pile........  Vibratory               20         10         30         10         10         10
                                Installation.
----------------------------------------------------------------------------------------------------------------
                                                  Template Pile
----------------------------------------------------------------------------------------------------------------
24-in Steel Pipe Pile........  Vibratory               20         10         30         20         10         10
                                Installation
                                and removal.
----------------------------------------------------------------------------------------------------------------

    Protected Species Observers (PSOs)--The number and placement of 
PSOs during all construction activities (described in the Proposed 
Monitoring and Reporting section) would ensure that the entire shutdown 
zone is visible during impact pile driving. In such cases, PSOs would 
monitor the Level A harassment zone and corresponding shutdown zone to 
the greatest extent practicable. CBS would employ at least three PSOs 
for all pile driving activities.
    Monitoring for Level A and Level B Harassment--PSOs would monitor 
the shutdown zones and beyond to the extent that PSOs can see. 
Monitoring beyond the shutdown zones enables observers to be aware of 
and communicate the presence of marine mammals in the project areas 
outside the shutdown zones and thus prepare for a potential cessation 
of activity should the animal enter the shutdown zone. If a marine 
mammal enters either harassment zone, PSOs will document the marine 
mammal's presence and behavior.
    Pre-and Post-Activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving of 30 
minutes or longer occurs, PSOs would observe the shutdown zones and as 
much as the harassment zones as possible for a period of 30 minutes. 
Pre-start clearance monitoring must be conducted during periods of 
visibility sufficient for the lead PSO to determine that the shutdown 
zones are clear of marine mammals. If the shutdown zone is obscured by 
fog or poor lighting conditions, in-water construction activity will 
not be initiated until the entire shutdown zone is visible. 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 shutdown 
zones, pile driving activity 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 
or 15 minutes have passed without re-detection of the animal. If a 
marine mammal for which take by Level B harassment is authorized is 
present in the Level B harassment zone, activities may begin.
    Soft-Start--The use of soft-start procedures are believed to 
provide additional protection to marine mammals by providing warning 
and/or giving marine mammals a chance to leave the area prior to the 
hammer operating at full capacity. For impact pile driving, contractors 
would be required to provide an initial set of three strikes from the 
hammer at reduced energy, with each strike followed by a 30-second 
waiting period. This procedure would be conducted a total of three 
times before impact pile driving begins. Soft start would 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. Soft start is not required during vibratory pile 
driving activities.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of 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. Note that the applicant opted to forgo the use of a 
bubble curtain as a mitigation measure as its use would decrease 
production rates due to the need to reposition the curtain around piles 
and vessel traffic, the need to maintain and operate the compressor, 
and delays associated with mechanical malfunctions.

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.

[[Page 56338]]

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 while conducting the activities. 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 activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.
    Visual Monitoring--Marine mammal monitoring during pile driving 
activities must be conducted by NMFS-approved PSOs in a manner 
consistent with the following:
     PSOs must be independent of the activity contractor (for 
example, employed by a subcontractor), 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 
incidental take authorization;
     Other PSOs may substitute other relevant experience, 
education (degree in biological science or related field) or training 
for experience performing the duties of a PSO during construction 
activities pursuant to a NMFS-issued incidental take authorization;
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator will be designated. The lead 
observer will be required to have prior experience working as a marine 
mammal observer during construction activity pursuant to a NMFS-issued 
incidental take authorization; and,
     PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA.
    PSOs should also 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 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 note 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.
    Visual monitoring would be conducted by a minimum of three trained 
PSOs positioned at suitable vantage points, such as the project site, 
Sawmill Creek Road and Medveje Hatchery (see figure 1 in the Marine 
Mammal Mitigation and Monitoring Plan). During vibratory pile driving, 
at least one PSO would have an unobstructed view of all water within 
the shutdown zone. During impact pile driving, a second PSO would be 
placed at Sawmill Creek Road to ensure the largest shutdown zone 
extending into Eastern Channel is observable and a third PSO would be 
placed at Medvejie Hatchery to ensure as much of the shutdown zone in 
Silver Bay is observable as possible. All PSOs would be stationed on 
elevated platforms to aid in monitoring marine mammals.
    Monitoring would be conducted 30 minutes before, during, and 30 
minutes after all in water construction activities. In addition, PSOs 
will record all incidents of marine mammal occurrence, regardless of 
distance from activity, and will document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving 
activities include the time to install or remove a single pile or 
series of piles, as long as the time elapsed between uses of the pile 
driving equipment is no more than 30 minutes.

Reporting

    CBS would submit a draft marine mammal monitoring report to NMFS 
within 90 days after the completion of pile driving activities, or 60 
days prior to a requested date of issuance of any future IHAs for the 
project, or other projects at the same location, whichever comes first. 
The marine mammal monitoring report will include an overall description 
of work completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report will include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including: (1) the number and type of piles that 
were driven and the method (e.g., impact or vibratory); and, (2) total 
duration of driving time for each pile (vibratory driving) and 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: (1) name of PSO who sighted the animal(s) and PSO location 
and activity at time of sighting; (2) time of sighting; (3) 
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; (4) 
distance and location of each observed marine mammal relative to the 
pile being driven for each sighting; (5) estimated number of animals 
(min/max/best estimate); (6) estimated number of animals by cohort 
(adults, juveniles, neonates, group composition, etc.); (7) animal's 
closest point of approach and estimated time spent within the 
harassment zone; and,

[[Page 56339]]

(8) 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, by species; and,
     Detailed information about implementation of any 
mitigation (e.g., shutdowns and delays), a description of specific 
actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    A final report must be prepared and submitted within 30 calendar 
days following receipt of any NMFS comments on the draft report. If no 
comments are received from NMFS within 30 calendar days of receipt of 
the draft report, the report shall be considered final. All PSO data 
would be submitted electronically in a format that can be queried such 
as a spreadsheet or database and would be submitted with the draft 
marine mammal report.
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the Holder must report the 
incident to the OPR, NMFS ([email protected] and 
[email protected]) and Alaska Regional Stranding network (877-925-
7773) as soon as feasible. If the death or injury was clearly caused by 
the specified activity, the Holder must immediately cease the 
activities until NMFS OPR 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 this IHA. The 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,
     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 impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), 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' 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 baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the discussion of our analysis applies to all 
the species listed in table 2, given that the anticipated effects of 
this activity on these different marine mammal stocks are expected to 
be similar. There is little information about the nature or severity of 
the impacts, or the size, status, or structure of any of these species 
or stocks that would lead to a different analysis for this activity.
    Pile driving and removal 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 and 
removal. Potential takes could occur if individuals are present in the 
ensonified zone when these activities are underway.
    No serious injury or mortality is expected, even in the absence of 
required mitigation measures, given the nature of the activities. 
Further, no take by Level A harassment is anticipated for gray whale, 
killer whale, Pacific white-sided dolphin, California sea lion, and 
Northern fur seal due to the application of planned mitigation 
measures, such as shutdown zones that encompass the Level A harassment 
zones for the species, the rarity of the species near the action area, 
and the small Level A harassment zones (for mid-frequency cetaceans 
only) (see Proposed Mitigation section).
    Take by Level A harassment is proposed for authorization for four 
species (humpback whale, harbor porpoise, harbor seal, and Steller sea 
lion). Any take by Level A harassment is expected to arise from, at 
most, a small degree of PTS (i.e., minor degradation of hearing 
capabilities within regions of hearing that align most completely with 
the energy produced by impact pile driving such as the low-frequency 
region below 2 kHz), not severe hearing impairment or impairment within 
the ranges of greatest hearing sensitivity. 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.
    Further, the amount of take proposed for authorization by Level A 
harassment is very low for the marine mammal stocks and species. For 
five species, NMFS anticipates no take by Level A harassment over the 
duration of CBS's planned activities; NMFS expects no more than 11 
takes by Level A harassment for humpback whale; 5 takes by Level A 
harassment for harbor porpoise; 34 takes by Level A harassment for 
harbor seal NMFS; and 89 takes by Level A harassment for Steller sea 
lion. If hearing impairment occurs, it is most likely that the affected 
animal would lose only a few dB in its hearing sensitivity. Due to the 
small degree anticipated, any PTS potential incurred would not be 
expected to affect the reproductive success or survival of any 
individuals, much less result in adverse impacts on the species or 
stock.
    Additionally, some subset of the individuals that are behaviorally 
harassed could also simultaneously incur some small degree of TTS for a 
short duration of time. However, since the hearing sensitivity of 
individuals that incur TTS is expected to recover completely within 
minutes to hours, it is unlikely that the brief hearing impairment 
would affect the individual's long-term ability to forage and 
communicate with conspecifics,

[[Page 56340]]

and would therefore not likely impact reproduction or survival of any 
individual marine mammal, let alone adversely affect rates of 
recruitment or survival of the species or stock.
    Effects on individuals that are taken by Level B harassment in the 
form of behavioral disruption, on the basis of reports in the 
literature as well as monitoring from other similar activities, would 
likely be limited to reactions such as avoidance, increased swimming 
speeds, increased surfacing time, or decreased foraging (if such 
activity were occurring) (e.g., Thorson and Reyff, 2006). Most likely, 
individuals would simply move away from the sound source and 
temporarily avoid the area where pile driving is occurring. If sound 
produced by project activities is sufficiently disturbing, animals are 
likely to simply avoid the area while the activities are occurring. We 
expect that any avoidance of the project areas by marine mammals would 
be temporary in nature and that any marine mammals that avoid the 
project areas during construction would not be permanently displaced. 
Short-term avoidance of the project areas and energetic impacts of 
interrupted foraging or other important behaviors is unlikely to affect 
the reproduction or survival of individual marine mammals, and the 
effects of behavioral disturbance on individuals is not likely to 
accrue in a manner that would affect the rates of recruitment or 
survival of any affected stock.
    The project is also not expected to have significant adverse 
effects on affected marine mammals' habitats. The project activities 
would not modify existing marine mammal habitat for a significant 
amount of time. The activities may cause a low level of turbidity in 
the water column and some fish may leave the area of disturbance, thus 
temporarily impacting marine mammals' foraging opportunities in a 
limited portion of the foraging range; but, because of the short 
duration of the activities and the relatively small area of the habitat 
that may be affected (with no known particular importance to marine 
mammals), the impacts to marine mammal habitat are not expected to 
cause significant or long-term negative consequences.
    While Steller sea lions are common in the project area, there are 
no essential primary constituent elements, such as haulouts or 
rookeries, present. The nearest haulout is well over 25 km away. 
Therefore, the project is not expected to have significant adverse 
effects on the critical habitat of Western DPS Steller sea lions. No 
areas of specific biological importance (e.g., ESA critical habitat, 
BIAs, or other areas) for any other species are known to co-occur with 
the project area.
    In addition, it is unlikely that minor noise effects in a small, 
localized area of habitat would have any effect on each stock's ability 
to recover. In combination, we believe that these factors, as well as 
the available body of evidence from other similar activities, 
demonstrate that the potential effects of the specified activities 
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 any of the species 
or stocks through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or 
authorized;
     Level A harassment would be very small amounts of a low 
degree;
     Take by Level A harassment of only humpback whale, harbor 
porpoise, Steller sea lions and harbor seals;
     For all species, Silver Bay and East Channel are a very 
small and peripheral part of their range;
     Anticipated takes by Level B harassment are relatively low 
for all stocks. Level B harassment would be primarily in the form of 
behavioral disturbance, resulting in avoidance of the project areas 
around where impact or vibratory pile driving is occurring, with some 
low-level TTS that may limit the detection of acoustic cues for 
relatively brief amounts of time in relatively confined footprints of 
activities;
     Effects on species that serve as prey for marine mammals 
from the activities are expected to be short-term and, therefore, any 
associated impacts on marine mammal feeding are not expected to result 
in significant or long-term consequences for individuals, or to accrue 
to adverse impacts on their populations;
     The ensonified areas are very small relative to the 
overall habitat ranges of all species and stocks, and would not 
adversely affect ESA-designated critical habitat for any species or any 
areas of known biological importance;
     The lack of anticipated significant or long-term negative 
effects to marine mammal habitat; and,
     CBS would implement mitigation measures including visual 
monitoring, soft-start, 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.
    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 previously, only take of small numbers of marine mammals 
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 amount of take NMFS proposed to authorize is below one third of 
the estimated stock abundance for all species. This is likely a 
conservative estimate because we assume all takes are of different 
individual animals, which likely would not be the case. Some 
individuals may return multiple times in a day, but PSOs would count 
them as separate takes if they cannot be individually identified.
    The most recent abundance estimate for the Mexico-North Pacific 
stock of humpback whale is likely unreliable as it is more than 8 years 
old. The most relevant estimate of this stock's abundance in Southeast 
Alaska is 918 humpback whales (Wade, 2021), so the 4 proposed takes by 
Level B harassment and 1 proposed take by Level A harassment is small 
relative to the estimated abundance (<1 percent), even if each proposed 
take occurred to a new individual.
    There is no abundance information available for the Yakutat/
Southeast Alaska stock of harbor porpoise. However, the take numbers 
are sufficiently small (13 takes by Level B harassment and 9 takes by 
Level A harassment) that we can safely assume

[[Page 56341]]

that they are small relative to any reasonable assumption of likely 
population abundance for these stocks. For reference, current abundance 
estimates for harbor porpoise stocks in southeast Alaska include 1,619 
(Northern Southeast Alaska Inland Waters) and 890 (Southern Southeast 
Alaska Inland Waters).
    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 would be taken relative to the population 
size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity that: 
(1) 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) cannot 
be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    For marine mammals, Alaska Natives have traditionally harvested 
harbor seals and Steller sea lions in Sitka, Alaska. During the most 
recent ADF&G subsistence harvest report (2013), about 11 percent of 
Sitka households used subsistence-caught marine mammals, however, this 
is the most recent data available and there has not been a survey since 
2013 (ADF&G, 2023).
    The proposed project is not likely to adversely impact the 
availability of any marine mammal species or stocks that are commonly 
used for subsistence purposes or impact subsistence harvest of marine 
mammals in the region because:
     There is no recent recorded subsistence harvest of marine 
mammals in the area;
     Construction activities are temporary and localized to the 
Gary Paxton Industrial Park, and industrial area;
     Construction will not take place during the herring 
spawning season when subsistence species are more active;
     Mitigation measures will be implemented to minimize 
disturbance of marine mammals in the action area; and,
     The project will not result in significant changes to 
availability of subsistence resources.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there will 
not be an unmitigable adverse impact on subsistence uses from CBS's 
proposed activities.

Endangered Species Act

    Section 7(a)(2) of the ESA of 1973 (ESA; 16 U.S.C. 1531 et seq.) 
requires that each Federal agency insure that any action it authorizes, 
funds, or carries out is not likely to jeopardize the continued 
existence of any endangered or threatened species or result in the 
destruction or adverse modification of designated critical habitat. To 
ensure ESA compliance for the issuance of IHAs, NMFS consults 
internally whenever we propose to authorize take for endangered or 
threatened species, in this case with the Alaska Regional Office 
(AKRO).
    NMFS is proposing to authorize take of western DPS of Steller sea 
lions and the Mexico DPS of humpback whales, which are listed under the 
ESA.
    The Permits and Conservation Division has requested initiation of 
section 7 consultation with the AKRO for the issuance of this IHA. NMFS 
will conclude the ESA consultation prior to reaching a determination 
regarding the proposed issuance of the authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to CBS for conducting Gary Paxton Industrial Park Vessel 
Haulout project in Sitka, Alaska between October 2024 and March 2025, 
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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

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 pile 
driving and removal activities. We also request 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, 1-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 
Activity section of this notice is planned, or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond 1 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: July 2, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-15012 Filed 7-8-24; 8:45 am]
BILLING CODE 3510-22-P