Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Construction Activities Associated With the Murray St. Bridge Seismic Retrofit Project in Santa Cruz, California, 12316-12334 [2023-03910]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 38 (Monday, February 27, 2023)]
[Notices]
[Pages 12316-12334]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-03910]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC607]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Construction Activities Associated 
With the Murray St. Bridge Seismic Retrofit Project in Santa Cruz, 
California

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

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

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SUMMARY: NMFS has received a request from the City of Santa Cruz for 
authorization to take marine mammals incidental to 2 years of 
construction activities associated with the Murray St. Bridge Seismic 
Retrofit Project in Santa Cruz, California. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue two consecutive 1-year incidental harassment 
authorizations (IHAs) 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 Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorization and agency responses will be 
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than March 
29, 2023.

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

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

SUPPLEMENTARY INFORMATION:

Background

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

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

Summary of Request

    On April 19, 2022, NMFS received a request from the City of Santa 
Cruz (the City) for two consecutive 1-year IHAs to take marine mammals 
incidental to construction activities associated with the Murray St. 
Bridge seismic retrofit project in Santa Cruz, CA. Following NMFS' 
review of the application, the City submitted revised versions on 
August 25, 2022, October 25, 2022, and December 13, 2022, and a final 
revised version on January 12, 2023. The application was deemed 
adequate and complete on January 24, 2023. The City's request is for 
take of small numbers of California sea lions (Zalophus californianus) 
and harbor seals (Phoca vitulina richardii) by Level

[[Page 12317]]

B harassment and take of small numbers of harbor seals by Level A 
harassment. Neither the City nor NMFS expect serious injury or 
mortality to result from this activity and, therefore, IHAs are 
appropriate.

Description of Proposed Activity

Overview

    The City plans to conduct a seismic retrofit on the Murray St. 
Bridge which spans the Santa Cruz Small Craft Harbor. As part of the 
proposed project, the City would use vibratory pile extraction to 
temporarily remove docks and associated piles to accommodate 
construction access to the bridge. Impact pile driving would be used to 
install additional bridge support piles. In order to facilitate 
installation of bridge piles, vibratory extraction may be used to 
construct a temporary trestle. As an alternative to the trestle, a 
temporary barge may be constructed instead. The purpose of the project 
is to provide the bridge with additional vertical support and 
resistance to lateral seismic forces by installing additional pilings 
and structural support elements.
    The City's proposed activity includes impact and vibratory pile 
driving and vibratory pile removal, which may result in the incidental 
take of marine mammals by Level A and Level B harassment. The Murray 
St. Bridge proposed project area includes waters within the Santa Cruz 
Small Craft Harbor and adjacent lands managed by the Santa Cruz Port 
District. Construction activities would span the course of 2 years, 
with the first year beginning on July 1, 2023 and lasting through July 
31, 2023. The second year of construction activities would begin on 
July 1, 2024 and last through September 15, 2024.
    The City has requested an IHA for each of the 2 project years. 
However, given the City has applied for authorization for both project 
years concurrently and projects use similar activities, NMFS is issuing 
this single Federal Register notice to solicit public comments on the 
issuance of the two similar, but separate, IHAs.

Dates and Duration

    The City anticipates that the bridge seismic retrofit will occur 
over 2 years. The in-work window during Year 1 would occur from July 1 
to July 31, 2023 with approximately 14 in-water construction days 
consisting of vibratory pile removal of the FF dock (Table 1). The in-
water work window during Year 2 would include approximately 98 in-water 
construction days spanning from July 1 to September 15, 2024 (Table 1), 
including approximately 97 days of in-water impact (37 days) and 
vibratory (60 days) pile installation and 1 day of in-water vibratory 
pile removal. All in-water construction activities would be limited to 
July 1 through mid-November each year due to timing restrictions to 
protect federally listed salmonids. An in-water work day assumes up to 
approximately 8 hours of pile driving or removal activities with only 
one pile being driven or extracted at a time.

                                                Table 1--Proposed In-Water Construction Activity Schedule
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                 Estimated      Estimated       Total
             Activity                    Pile type                   Method              Number of   Piles/day  blow count/   duration/pile   estimated
                                                                                           piles                    pile          (min)          days
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Remove dock FF South.............  14'' p/c concrete     Vibratory Extraction..........         30          10          n/a              48           14
                                    pile.
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Total days Year 1......................................................................................................................           14
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Remove Dock FF temporary           14'' p/c concrete     Impact Install................         30       \1\ 4          200             n/a           14
 relocation.                        pile.                Vibratory Extraction..........                                 n/a             240
--------------------------------------------------------------------------------------------------------------------------------------------------------
Relocate Dock BY.................  14'' p/c concrete     Vibratory Extraction..........          5           5          n/a              96            1
                                    pile.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Install new permanent bridge       30'' steel in CISS    Impact Install................         18    \3\ 0.67        2,500             n/a           23
 piles (bents 4-8) \2\.             (bents 5-8) 30''     Vibratory Install.............                                 n/a             720
                                    steel in CIDH (bent
                                    4).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Install temporary trestles.......  20'' steel pipe pile  Vibratory Install.............         72           3          n/a             160           60
                                    \4\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Total days Year 2......................................................................................................................           98
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Total project days.....................................................................................................................          112
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Assumes two vibratory drivers.
\2\ Bent 4 is underwater at high tide.
\3\ 1.5 days to install each pile.
\4\ 20-inch piles represent the maximum size piles that may be used for the trestle.

Specific Geographic Region

    The Murray St. Bridge retrofit project area includes waters within 
the Santa Cruz Small Craft Harbor (the Harbor) at the northern tip of 
Monterey Bay and adjacent lands managed by the Santa Cruz Port District 
(Figure 1). The project area includes open waters, docks, and other 
potential haul-out features of the Harbor from the Harbor Launch Ramp 
area, including the fuel dock and Vessel Assist dock, to 500 feet 
(152.4 meters (m)) upstream of the boundary of the Area of Impact 
(Figure 1). The Harbor intertidal environment is defined by shore 
bottom substrates, rocky shores, and substrate provided by floating 
docks. Bottom substrate is impacted by seasonal deposition of silt from 
streams that flow into the Harbor. Project work will begin on the 
eastern side of Harbor and progress to the western side.
    Ambient underwater noise levels in the proposed project area are 
likely similar to those measured in Monterey Harbor (Illingworth and 
Rodkin, 2012), which ranged from 110 to 120 dB. Illingworth and Rodkin 
(2012) found frequent acoustic events, such as boat traffic, to cause 
noise levels to exceed 120 dB during monitoring in Monterey Harbor, and 
the same is likely to occur in the proposed project area.
BILLING CODE 3510-22-P

[[Page 12318]]

[GRAPHIC] [TIFF OMITTED] TN27FE23.002

Figure 1--Proposed Project Area

BILLING CODE 3510-10-C

Detailed Description of the Specified Activity

    The Murray St. Bridge seismic retrofit project is proposed for 
construction in nine phases over an approximate 2 year and 4 month 
period, commencing in summer 2023. The City has applied for two IHAs 
for Year 1 and Year 2 of in-water construction activities. The City 
plans to apply for an additional IHA to cover any remaining 
construction work remaining at the end of Year 2. In-water construction 
activities include the removal and temporary relocation of docks to 
accommodate construction access, pile driving, potential installation 
of piles for a construction trestle from the bridge or barge 
construction, transport of materials, and replacement of harbor docks 
upon completion of the project.
    Removal and replacement of boat berths--To accommodate construction 
staging and in-water construction activities, the City plans to 
temporarily relocate berths at Dock FF and Dock BY (Boat Yard on east 
side) to existing visitor berths. These docks will be reconstructed 
upon the completion of the bridge retrofit project. Removal of these 
docks would involve vibratory extraction of 30 14'' precast concrete 
piles and take place over 14 days in July 2023 during Year 1 as well as 
over 15 days in July 2024 during Year 2. During Year 1, a maximum of 10 
piles would be removed per day from Dock FF. During Year 2, a maximum 
of four piles per day would be removed from Dock FF over the course of 
14 days and five piles would be removed from Dock BY over the course of 
a day. Reinstallation of piles for Dock FF and Dock BY would occur in 
October to November 2025 and be covered under a separate IHA. The 
reinstalled berths would be plastic, wood, or concrete over 
polyethylene float, and be anchored with pilings.

[[Page 12319]]

    Pile installation--The most intensive in-water activity would be 
the installation of new bridge support piles at Bents 4 through 8 from 
August through September during Year 2. Installation at Bents 5 through 
8 would involve impact and vibratory pile driving of 16 (4 per Bent) 
30-inch Cast-in-steel-shell (CISS) piles. At Bents 5 through 8, 30-inch 
diameter steel casings will be driven to either refusal at rock or into 
a shaft drilled within rock, depending upon the location. Two 
additional 30-inch steel piles will be driven using impact and 
vibratory pile driving at Ben 4, although these piles are only 
submerged in water during high tide. Bridge piles will be partially or 
entirely vibrated into the Harbor substrate, depending upon bottom 
type, instead of driving them entirely by impact pile driving. A 
vibratory hammer would be used to start driving all piles, but an 
impact hammer may be required to complete pile driving, depending upon 
the density of the subsurface materials. Overall, pile installation is 
expected to last approximately 23 days, with 1.5 days required to drive 
each 30-inch diameter steel pile.
    Construction barge and/or temporary trestle--Installation of an in-
water barge or temporary bridge trestle is planned to accommodate 
equipment for pile installation. Work within the waterway will require 
either the use of a barge or the construction of a temporary trestle to 
provide a work platform. If a barge is utilized, prefabricated modular 
units may be brought to the site and locked together. This platform can 
be installed, reconfigured, and removed relatively quickly, but the 
system is not suitable for areas that are too narrow to accommodate the 
modules. If areas are too narrow, a trestle would likely be 
constructed.
    Construction of a trestle would vary depending upon materials 
available to contractors, however, a potential trestle would be 60-foot 
(18.3 meters (m)) long and comprised of steel girders over the Harbor 
navigation channel. The spans would be supported on false work bents, 
constructed of steel piles. Up to 72 20-inch steel beams (potentially, 
the contractor may decide to use 120 12-inch steel beams instead) would 
be required for a trestle spanning the channel. Vibratory drivers would 
be used to install the trestle during Year 2 and would require an 
estimated 60 days to install. The trestle would be removed after 
construction is complete in 2025. This removal would be covered under a 
separate IHA. Barge construction is likely to be less impactful that 
trestle construction, therefore, trestle construction is included in 
the below analysis and barge construction is not discussed further.
    The proposed project also includes construction activities that are 
located on land. These activities include the demolition, pile and 
anchor installation outside of the waterway, bridge construction on the 
northern and southern ends of the bridge as well as the construction of 
barrier railings and project features below the bridge road surface, 
contractor staging for construction activities in the boat yard near 
the eastern edge of the bridge, temporary bypass of the sewer line, and 
temporary harbor facility relocation. These land-based construction 
activities are not expected to result in take, and are therefore not 
discussed further.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, incorporated here by reference, instead of 
reprinting the information. Additional information regarding population 
trends and threats may be found in NMFS' Stock Assessment Reports 
(SARs; 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 expected to occur, 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 stocks managed under the MMPA in this region 
are assessed in NMFS' U.S. Pacific 2022 draft SARs. All values 
presented in Table 2 are the most recent available at the time of 
publication and are available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                     Table 2--Marine Mammal Species \4\ Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    California sea lion.............  Zalophus californianus.  U.S....................  -, -, N             257,606 (N/A, 233,515,     14,011       >320
                                                                                                             2014).
Family Phocidae (earless seals):

[[Page 12320]]

 
    Harbor seal.....................  Phoca vitulina.........  California.............  -, -, N             30,968 (N/A, 27,348,        1,641         43
                                                                                                             2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable [explain if this is
  the case].
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ 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)).

    As indicated above, the two species (with two managed stocks) in 
Table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. While bottlenose 
dolphins (Tursiops truncatus) and harbor porpoises (Phocoena phocoena) 
have been reported in the area, the temporal and/or spatial occurrence 
of these species is such that take is not expected to occur, and they 
are not discussed further beyond the explanation provided here. 
Bottlenose dolphins and harbor porpoises may transit nearshore areas 
just outside the mouth of the Harbor (Carretta et al., 2022). However, 
these species were not detected during any surveys of the Harbor area 
and are expected to remain outside the Harbor and beyond the proposed 
project area.
    In addition, the southern sea otter (Enhydra lutris nereis) may be 
found in the Harbor. However, sea otters are managed by the U.S. Fish 
and Wildlife Service and are not considered further in this document.

California Sea Lions

    California sea lions are known to breed mainly on offshore islands, 
spanning from Southern California's Channel Islands to Mexico during 
the spring (Heath and Perrin, 2008), although pups have also been born 
on A[ntilde]o Nuevo and the Farallon Islands (TMMC, 2020). During the 
non-breeding season, adult and sub-adult males as well as juveniles 
migrate northward along the coast, to central and northern California, 
Oregon, Washington, and Vancouver Island (Jefferson et al., 1993). They 
return south the following spring (Lowry and Forney, 2005; Heath and 
Perrin, 2008) while females tend to remain closer to rookeries 
(Antonelis et al., 1990; Melin et al., 2008). Based upon statistical 
analysis of annual pup count, annual survivorship, and human-induced 
impacts, the California stock appears to have experienced an annual 
increase from 1975-2014 (Laake et al., 2018). The Harbor does not 
provide mating, breeding, or pupping habitat for California sea lions.
    California sea lions are incidental visitors to the Harbor, 
appearing in the greatest numbers when fish are abundant in the area. 
Based upon surveys conducted in the Harbor by EcoSystems West 
Consulting Group during December 2006, October 2009, and February to 
March 2022, California sea lions may use the Harbor occasionally for 
hauling out, and specific haul-out locations in the Harbor may vary. In 
2009, the closest regular sea lion haul-out location to the project 
area was the Municipal Wharf, although in 2006 and 2009, sea lions were 
also observed to haul out near the launch ramp, fuel dock, and Vessel 
Assist Dock (see Figure 4 in the Application). However, in 2022, no 
hauled out sea lions were observed in the Harbor.
    California sea lions may also use the Harbor for foraging. They 
feed seasonally on schooling fish and cephalopods, including salmon, 
herring, sardines, anchovy, mackerel, whiting, rockfish, and squid 
(Lowry et al., 1990, 1991; Lowry and Carretta, 1999; Weise 2000; 
Carretta et al., 2022). Seasonal and annual dietary shifts vary with 
environmental fluctuations that affect prey populations. In central 
California sea lion populations, short term seasonal variations in diet 
are related to prey movement and life history patterns while long-term 
annual changes correlate to large-scale ocean climate shifts and 
foraging competition with commercial fisheries (Weise and Harvey, 2008; 
McClatchie et al., 2016). Climate change, specifically increasing sea 
surface temperatures in the California current, negatively impact prey 
species availability and reduce California sea lion survival rates 
(DeLong et al., 2017; Laake et al., 2018). Other conservation concerns 
for California sea lions include vessel strikes, non-commercial fishery 
human caused mortality, hookworms, and competition for forage with 
commercial fisheries (Carretta et al., 2018; Carretta et al., 2022).
    California sea lions experienced a UME, not correlated to an El 
Ni[ntilde]o event, from 2013-2017 (Carretta et al., 2022). Pup and 
juvenile age classes experienced high mortality during this time, 
likely attributed to sea lion prey availability, specifically sardines. 
California sea lions are also susceptible to the algal neurotoxin, 
domoic acid (Brodie et al., 2006; Carretta et al., 2022). This 
neurotoxin is expected to cause future mortalities among California sea 
lions due to the prevalence of harmful algal blooms within their 
habitat.

Harbor Seals

    Pacific harbor seals are distributed from Baja California north to 
the Aleutian Islands of Alaska. Harbor seals do not make extensive 
pelagic migrations, but may travel hundreds of kilometers to find food 
or suitable breeding areas (Herder, 1986; Harvey and Goley, 2011; 
Carretta et al., 2022). Seals primarily haul out on remote mainland and 
island beaches, reefs, and estuary areas. At haul-outs, they congregate 
to rest, socialize, breed, and molt.
    Harbor seals may use the Harbor seasonally for foraging or hauling 
out. Documented haul-out locations may vary across years, and harbor 
seals have been observed foraging around haul-out locations. During 
December 2006, six harbor seals were observed hauled out on dock FF at 
night. Docks F, FF, and S were primary haul-out areas in October 2009, 
however, no harbor seals were observed hauled out during February and 
March 2022. Based upon the Ecosystems West surveys, harbor seals were 
more likely to be hauled out

[[Page 12321]]

in Harbor in the early morning hours. Grigg et al. (2009) reported 
seasonal shifts in harbor seal movements based on prey availability. 
The highest numbers of harbor seals were observed in the Harbor during 
late summer, fall, and winter, outside of the breeding season (March-
May), and outside of the molting season (June-July). The Harbor does 
not provide breeding, molting, or pupping habitat for harbor seals.
    Harbor seals were observed foraging in the Harbor during December 
2006 and October 2009, in close proximity to primary haul-out sites, 
such as Docks F and FF. In 2009, foraging harbor seals were documented 
both in the Upper Harbor upstream of the Murray St. Bridge and within 
the lower Harbor downstream of the Murray St. Bridge and near Dock FF. 
Harbor seals may forage on a variety of fish, crustaceans, and 
cephalopods in shallow intertidal waters. Fish prey species may include 
yellowfin goby, northern anchovy, Pacific herring, staghorn sculpin, 
plainfish midshipman, and white croaker (Harvey and Torok, 1994).

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.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 3.

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

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

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 section later in this document includes a 
quantitative analysis of the number of individuals that are expected to 
be taken by this activity. The Negligible Impact Analysis and 
Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and 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.
    Acoustic effects on marine mammals during the specified activities 
can occur from impact pile driving and vibratory driving and removal. 
The effects of underwater noise from the City's proposed activities 
have the potential to result in Level A or Level B harassment of marine 
mammals in the project area.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far (ANSI, 1995). The sound level of an area is 
defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., waves, wind, 
precipitation, earthquakes, ice, atmospheric sound), biological (e.g., 
sounds produced by marine mammals, fish, and invertebrates), and 
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 
decibels (dB) from day to day (Richardson et al., 1995). The result is 
that, depending on the source type and

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its intensity, sound from the specified activities 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, sonic 
booms, impact pile driving) are typically transient, brief (less than 1 
second), broadband, and consist of high peak sound pressure with rapid 
rise time and rapid decay (ANSI, 1986; NIOSH, 1998; NMFS, 2018). Non-
impulsive sounds (e.g., machinery operations such as drilling or 
dredging, vibratory pile driving, underwater chainsaws, and active 
sonar systems) can be broadband, narrowband or tonal, brief or 
prolonged (continuous or intermittent), and typically do not have the 
high peak sound pressure with raid rise/decay time that impulsive 
sounds do (ANSI, 1995; NIOSH, 1998; NMFS, 2018). The distinction 
between these two sound types is important because they have differing 
potential to cause physical effects, particularly with regard to 
hearing (e.g., Ward, 1997).
    Two types of hammers would be used on this project, impact and 
vibratory. Impact hammers operate by repeatedly dropping and/or pushing 
a heavy piston onto a pile to drive the pile into the substrate. Sound 
generated by impact hammers is considered impulsive. Vibratory hammers 
install piles by vibrating them and allowing the weight of the hammer 
to push them into the sediment. Vibratory hammers produce non-
impulsive, continuous sounds. Vibratory hammering generally produces 
sound pressure levels (SPLs) 10 to 20 dB lower than 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).
    The likely or possible impacts of the City's proposed activities on 
marine mammals could be generated from both non-acoustic and acoustic 
stressors. Potential non-acoustic stressors include the physical 
presence of the equipment, vessels, and personnel; however, we expect 
that any animals that approach the project site(s) close enough to be 
harassed due to the presence of equipment or personnel would be within 
the harassment zone from pile driving and would already be subject to 
harassment from the in-water activities. Therefore, any impacts to 
marine mammals are expected to primarily be acoustic in nature. 
Acoustic stressors are generated by heavy equipment operation during 
pile installation and removal (i.e., impact and vibratory pile driving 
and removal).

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving equipment is the primary means by which 
marine mammals may be harassed from the City's specified activities. In 
general, animals exposed to natural or anthropogenic sound may 
experience physical and psychological effects, ranging in magnitude 
from none to severe (Southall et al., 2007). Generally, exposure to 
pile driving and removal and other construction noise has the potential 
to result in auditory threshold shifts and behavioral reactions (e.g., 
avoidance, temporary cessation of foraging and vocalizing, changes in 
dive behavior). Exposure to anthropogenic noise can also lead to non-
observable physiological responses, such as an increase in stress 
hormones. Additional noise in a marine mammal's habitat can mask 
acoustic cues used by marine mammals to carry out daily functions, such 
as communication and predator and prey detection. The effects of pile 
driving and demolition 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. 
mother with calf), duration of exposure, the distance between the pile 
and the animal, received levels, behavior at time of exposure, and 
previous history with exposure (Wartzok et al., 2004; Southall et al., 
2007). Here we discuss physical auditory effects (threshold shifts) 
followed by behavioral effects and potential impacts on habitat. No 
physiological effects other than permanent threshold shift (PTS) and 
temporary threshold shift (TTS) are anticipated or proposed to be 
authorized, and therefore are not discussed further.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Available data 
from humans and other terrestrial mammals indicate that a 40 dB 
threshold shift approximates PTS onset (see Ward et al., 1958, 1959; 
Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; 
Henderson et al., 2008). PTS levels for marine mammals are estimates, 
because there are limited empirical data measuring PTS in marine 
mammals (e.g., Kastak et al., 2008), 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)--TTS is a temporary, reversible 
increase in the threshold of audibility at a specified frequency or 
portion of an individual's hearing range above a previously established 
reference level (NMFS, 2018). Based on data from cetacean TTS 
measurements (see Southall et al., 2007), a TTS of 6 dB is considered 
the minimum threshold shift clearly larger than any day-to-day or 
session-to-session variation in a subject's normal hearing ability 
(Schlundt et al., 2000; Finneran et al., 2000, 2002). As described in 
Finneran (2015), marine mammal studies have shown the amount of TTS 
increases with cumulative sound exposure level (SELcum) in 
an accelerating fashion: At low exposures with lower SELcum, 
the amount of TTS is typically small and the growth curves have shallow 
slopes. At exposures with higher SELcum, the growth curves 
become steeper and approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced,

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TTS can have effects on marine mammals ranging from discountable to 
serious (similar to those discussed in auditory masking, below). For 
example, a marine mammal may be able to readily compensate for a brief, 
relatively small amount of TTS in a non-critical frequency range that 
takes place during a time when the animal is traveling through the open 
ocean, where ambient noise is lower and there are not as many competing 
sounds present. Alternatively, a larger amount and longer duration of 
TTS sustained during time when communication is critical for successful 
mother/calf interactions could have more serious impacts. We note that 
reduced hearing sensitivity as a simple function of aging has been 
observed in marine mammals, as well as humans and other taxa (Southall 
et al., 2007), so we can infer that strategies exist for coping with 
this condition to some degree, though likely not without cost.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor 
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis), 
and five species of pinnipeds exposed to a limited number of sound 
sources (i.e., mostly tones and octave-band noise) in laboratory 
settings (Finneran, 2015). TTS was not observed in trained spotted 
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive 
noise at levels matching previous predictions of TTS onset (Reichmuth 
et al., 2016). In general, harbor seals and harbor porpoises have a 
lower TTS onset than other measured pinniped or cetacean species 
(Finneran, 2015). 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, 2019b, 2020a, 2020b). 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 
(Finneran et al., 2010; Kastelein et al., 2014; Kastelein et al., 
2015a; Mooney et al., 2009). 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.
    The potential for TTS from impact pile driving exists. After 
exposure to playbacks of impact pile driving sounds (rate 2,760 
strikes/hour) in captivity, mean TTS increased from 0 dB after 15 
minute exposure to 5 dB after 360 minute exposure; recovery occurred 
within 60 minutes (Kastelein et al., 2016). Additionally, the existing 
marine mammal TTS data come from a limited number of individuals within 
these species. No data are available on noise-induced hearing loss for 
mysticetes. Nonetheless, what we considered is the best available 
science. For summaries of data on TTS in marine mammals or for further 
discussion of TTS onset thresholds, please see Southall et al. (2007, 
2019), Finneran and Jenkins (2012), Finneran (2015), and Table 5 in 
NMFS (2018).
    Installing piles for this project requires impact pile driving. 
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 and 
removal also has the potential to behaviorally disturb marine mammals. 
Available studies show wide variation in response to underwater sound; 
therefore, it is difficult to predict specifically how any given sound 
in a particular instance might affect marine mammals perceiving the 
signal. If a marine mammal does react briefly to an underwater sound by 
changing its behavior or moving a small distance, the impacts of the 
change are unlikely to be significant to the individual, let alone the 
stock or population. However, if a sound source displaces marine 
mammals from an important feeding or breeding area for a prolonged 
period, impacts on individuals and populations could be significant 
(e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); or 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; Weilgart, 2007; Archer et al., 2010; Southall et al., 2021). 
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) as well as Nowacek et al. (2007); 
Ellison et al. (2012), and Gomez et al. (2016) for a review of studies 
involving marine mammal behavioral responses to sound.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 2007; 
Melc[oacute]n et al., 2012). In addition, behavioral state of the 
animal plays a role in the type and severity of a behavioral response, 
such as disruption to foraging (e.g., Sivle et al., 2016; Wensveen et 
al., 2017). 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 (Goldbogen et al., 2013).
    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., Selye, 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

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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 these projects based on observations 
of marine mammals during previous, similar projects in the area.
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al., 1995). Masking occurs when 
the receipt of a sound is interfered with by another coincident sound 
at similar frequencies and at similar or higher intensity, and may 
occur whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked. The 
masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt 
et al., 2009). The Harbor is heavily used by commercial and 
recreational vessels, and background sound levels in the area are 
already elevated. Normal ambient noise levels in the Harbor include 
vessel motors, heavy vehicular traffic on the bridge, and construction 
noise from the dry dock repair facility, commercial charters, and 
significant water traffic. Due to the transient nature of marine 
mammals to move and avoid disturbance, masking is not likely to have 
long-term impacts on marine mammal species within the proposed project 
area.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal that have the potential to cause behavioral harassment, 
depending on their distance from pile driving activities. 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 likely previously have been ``taken'' 
because of exposure to underwater sound above the behavioral harassment 
thresholds, which are generally larger than those associated with 
airborne sound. Thus, the behavioral harassment of these animals is 
already accounted for in these estimates of potential take. Therefore, 
we do not believe that authorization of incidental take resulting from 
airborne sound for pinnipeds is warranted, and airborne sound is not 
discussed further here.

Marine Mammal Habitat Effects

    The City's proposed construction activities could have localized, 
temporary impacts on marine mammal habitat, including prey, by 
increasing in-water sound pressure levels and slightly decreasing water 
quality. Increased noise levels may affect acoustic habitat (see 
masking discussion above) and adversely affect marine mammal prey in 
the vicinity of the project areas (see discussion below). During impact 
and vibratory pile driving or removal, elevated levels of underwater 
noise would ensonify the project area where both fishes and mammals 
occur, and could affect foraging success. Additionally, marine mammals 
may avoid the area during construction, however, displacement due to 
noise is expected to be temporary and is not expected to result in 
long-term effects to the individuals or populations. Construction 
activities are expected to be of short duration and would likely have 
temporary impacts on

[[Page 12325]]

marine mammal habitat through increases in underwater and airborne 
sound.
    A temporary and localized increase in turbidity near the seafloor 
would occur in the immediate area surrounding the area where piles are 
installed or removed. In general, turbidity associated with pile 
installation is localized to about a 25-ft (7.6-m) radius around the 
pile (Everitt et al., 1980). Any pinnipeds could avoid localized areas 
of turbidity. Local currents are anticipated to disburse any additional 
suspended sediments produced by project activities at moderate to rapid 
rates depending on tidal stage. Therefore, we expect the impact from 
increased turbidity levels to be discountable to marine mammals and do 
not discuss it further.
    In-Water Construction Effects on Potential Foraging Habitat--The 
area likely impacted by the Murray St. Bridge retrofit project is 
relatively small compared to the total available habitat in the Harbor. 
The proposed project area is highly influenced by anthropogenic 
activities, and provides limited foraging habitat for marine mammals. 
Furthermore, pile driving and removal at the proposed project site 
would not obstruct long-term movements or migration of marine mammals.
    Avoidance by potential prey (i.e., fish) of the immediate area due 
to the temporary loss of this foraging habitat is also possible. The 
duration of fish 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 
prey of the disturbed area would still leave significantly large areas 
of potential foraging habitat in the nearby vicinity.
    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, other marine mammals). Marine mammal prey varies by 
species, season, and location. Here, we describe studies regarding the 
effects of noise on known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). Depending on their hearing anatomy and peripheral sensory 
structures, which vary among species, fishes hear sounds using pressure 
and particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds 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; several are based on 
studies in support of large, multiyear bridge construction projects 
(e.g., Scholik and Yan, 2001; Popper and Hastings, 2009). Many 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). In response to pile driving, Pacific sardines and 
northern anchovies may exhibit an immediate startle response to 
individual strikes, but return to ``normal'' pre[hyphen]strike behavior 
following the conclusion of pile driving with no evidence of injury as 
a result (Appendix C in NAVFAC SW, 2014). 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; Popper et al., 
2005).
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours 
for one species. Impacts would be most severe when the individual fish 
is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    The most likely impact to fishes from pile driving and removal and 
construction activities at the project area would be temporary 
behavioral avoidance of the area. The duration of fish avoidance of 
this area after pile driving stops is unknown, but a rapid return to 
normal recruitment, distribution, and behavior is anticipated. In 
general, impacts to marine mammal prey species are expected to be minor 
and temporary. Further, it is anticipated that preparation activities 
for pile driving or removal (i.e., positioning of the hammer) and upon 
initial startup of devices would cause fish to move away from the 
affected area outside areas where injuries may occur. Therefore, 
relatively small portions of the proposed project area would be 
affected for short periods of time, and the potential for effects on 
fish to occur would be temporary and limited to the duration of sound-
generating activities.
    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 actions 
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 potential areas 
fish and marine mammal foraging habitat in the nearby vicinity. Thus, 
we conclude that impacts of the specified activities are not likely to 
have more than short-term adverse effects on any prey habitat or 
populations of prey species. Further, any impacts to marine mammal 
habitat are not expected to result in significant or long-term 
consequences for individual marine mammals, or to contribute to adverse 
impacts on their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers,'' and the negligible impact 
determinations.
    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);

[[Page 12326]]

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 source (i.e., impact 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 phocids because predicted auditory 
injury zones are larger than for otariids. Auditory injury is unlikely 
to occur for otariids. 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.
    The City of Santa Cruz's proposed construction activity includes 
the use of continuous (vibratory pile driving and removal) and 
impulsive (impact pile driving) sources, and therefore the RMS SPL 
thresholds of 120 and 160 dB re 1 [mu]Pa 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). The City's 
proposed activity includes the use of impulsive (impact hammer) and 
non-impulsive (vibratory hammer) 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: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                        PTS onset thresholds *  (received level)
            Hearing group             --------------------------------------------------------------------------
                                                 Impulsive                           Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans.........  Cell 1: L,0-pk,flat: 219 dB;   Cell 2: LE,,LF,24h: 199 dB.
                                        LE,,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans.........  Cell 3: L,0-pk,flat: 230 dB;   Cell 4: LE,,MF,24h: 198 dB.
                                        LE,,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans........  Cell 5: L,0-pk,flat: 202 dB;   Cell 6: LE,,HF,24h: 173 dB.
                                        LE,,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)...  Cell 7: L,0-pk,flat: 218 dB;   Cell 8: LE,,PW,24h: 201 dB.
                                        LE,,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)..  Cell 9: L,0-pk,flat: 232 dB;   Cell 10: LE,,OW,24h: 219 dB.
                                        LE,,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 are recommended for consideration.

[[Page 12327]]

 
Note: Peak sound pressure level (L,0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
  exposure level (LE,) has a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO, 2017). The subscript
  ``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within the
  generalized hearing range of marine mammals (i.e., 7 Hz to 160 kHz). 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
  weighted 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 thresholds will be exceeded.

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 by sound generated by the 
primary components of the project (i.e., impact and vibratory pile 
driving).
    In order to calculate distances to the Level A harassment and Level 
B harassment thresholds for the methods and piles being used in this 
project, the City used acoustic monitoring data from various similar 
locations to develop source levels for the different pile types, sizes, 
and methods proposed for use (Table 5).

                                         Table 5--Source Levels for Proposed Removal and Installation Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             Peak sound      Mean maximum   SEL (dB re
           Activity                 Location           Pile size/type          Method     pressure (dB re   RMS SPL (dB re   1 [mu]Pa2       Source
                                                                                             1 [mu]Pa)        1 [mu]Pa)        sec)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Removal of existing bridge      Bridge Bent 6.    14'' P/C concrete......  Vibratory....              171              163         155  NAVFAC SW, 2022.
 piles. Removal of dock FF&T     Dock FF & BY.
 piles.
Install new permanent bridge    Bridge Bents 4    30'' steel in CISS.....  Impact.......              210              190         177  Caltrans, 2015.
 piles.                          through 8.
Install new permanent bridge    Bridge Bents 4    30'' steel in CISS.....  Vibratory....              196              159         175  Caltrans, 2020.
 piles.                          through 8.
Install new permanent bridge    Dock FF&T piles.  14'' P/C concrete......  Impact.......              185              170         160  Caltrans, 2020.
 piles.
Install new permanent bridge    Dock FF&T piles.  14'' P/C concrete......  Vibratory....              171              163         155  NAVFAC SW, 2022.
 piles.
Install temporary trestle       Adjacent to       20'' steel \1\.........  Vibratory....              194              154          NA  Caltrans, 2015.
 piles.                          bridge.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ 24'' steel pipe used as a proxy for 20'' steel pile for vibratory pile driving.

Level B Harassment Zones

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

TL = B * Log10 (R1/R2),

where

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

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, which is the most appropriate 
assumption for the City's proposed activities. The City assumed an open 
water attenuation rate of 4.5 dB per doubling of distance. The Level B 
harassment zones and ensonified area for the City's proposed activities 
are shown in Table 6.

           Table 6--Distances to Level B Harassment Thresholds
------------------------------------------------------------------------
                                                       Projected  radial
                                                      distance  to Level
        Pile type/size                 Method            B  harassment
                                                        threshold  (m)
------------------------------------------------------------------------
                                 Year 1
------------------------------------------------------------------------
14'' P/C concrete............  Vibratory............               7,356
------------------------------------------------------------------------
                                 Year 2
------------------------------------------------------------------------
30'' steel pipe pile in CISS.  Impact...............               1,000
                               Vibratory............               3,981
------------------------------------------------------------------------
14'' p/c concrete............  Impact...............                  46
                               Vibratory............               7,356
------------------------------------------------------------------------

[[Page 12328]]

 
20'' steel pipe piles........  Vibratory............               1,848
------------------------------------------------------------------------

Level A Harassment Zones

    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 installation or removal, 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. The isopleths generated by the User 
Spreadsheet used the same TL coefficient as the Level B harassment zone 
calculations (i.e., the practical spreading value of 15). Inputs in the 
User Spreadsheet tool (i.e., number of piles per day, duration, and/or 
strikes per pile) are presented in Table 1. The maximum RMS SPL/SEL SPL 
for each pile type are presented in Table 5. Resulting Level A 
harassment isopleths are reported below in Table 7.

                               Table 7--Distances to Level A Harassment Thresholds
----------------------------------------------------------------------------------------------------------------
                                                                                  Projected distances to Level A
                                                                                     harassment threshold (m)
                Pile type/size                               Method              -------------------------------
                                                                                      Phocids        Otariids
----------------------------------------------------------------------------------------------------------------
                                                     Year 1
----------------------------------------------------------------------------------------------------------------
14'' P/C concrete.............................  Vibratory.......................            22.6             1.6
----------------------------------------------------------------------------------------------------------------
                                                     Year 2
----------------------------------------------------------------------------------------------------------------
30'' steel pipe pile in CISS..................  Impact..........................             300              22
                                                Vibratory.......................            12.3               1
----------------------------------------------------------------------------------------------------------------
14'' p/c concrete.............................  Impact..........................              13               1
                                                Vibratory.......................            22.6             1.6
----------------------------------------------------------------------------------------------------------------
20'' steel pipe piles.........................  Vibratory.......................             5.7             0.4
----------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information that 
will inform the take calculations. Unless otherwise specified, the term 
``pile driving'' in this section, and all following sections, may refer 
to either pile installation or removal. NMFS has carefully reviewed the 
City's analysis and concludes that it represents an appropriate and 
accurate method for estimating incidental take that may be caused by 
the City's activities.
    Daily occurrence estimates of marine mammals in the proposed 
project area are based upon marine mammal surveys conducted in the 
vicinity of the Murray St. Bridge by EcoSystems West Consulting Group. 
Survey sessions were conducted in December 2006, September 2009 through 
October 2009. Of these monitoring years, the maximum counts of 
California sea lions and harbor seals were observed in 2009 (Table 8). 
As the 2009 surveys occurred during the fall season and the proposed 
project would occur during the summer and fall seasons, the 2009 data 
are likely representative of maximum occurrences that could be expected 
in the proposed project area.

     Table 8--Maximum Counts of Species Likely Impacted by Proposed
                               Activities
------------------------------------------------------------------------
              Species                2006 Monitoring    2009 Monitoring
------------------------------------------------------------------------
California sea lion...............                  1                 15
Harbor seal.......................                  6                 11
------------------------------------------------------------------------


[[Page 12329]]

Take Estimation

    Here we describe how the information provided above is synthesized 
to produce a quantitative estimate of the take that is reasonably 
likely to occur and proposed for authorization.
    Maximum occurrence estimates (reported in Table 8) were multiplied 
by the number of days of pile removal and installation (14 days in Year 
1; 98 days in Year 2) to calculate estimated take by Level B harassment 
of California sea lions and harbor seals (Table 9). The City assumed a 
maximum of two harbor seals would be present in the proposed project 
area that may be impacted during the 37 days of impact pile driving. 
The expected occurrence of two harbor seals was multiplied by the 
number of impact pile driving days (37) to estimate take by Level A 
harassment of harbor seals. Given the very small Level A harassment 
isopleths for California sea lions and proposed mitigation measures, 
Level A harassment of California sea lions is not requested or 
expected. By using the sighting-based approach, take values are not 
affected by the estimated harassment distances from Tables 6 and 7. 
NMFS has carefully reviewed these methods and agrees with this 
approach.

               Table 9--Estimated Proposed Take by Level A and Level B Harassment and Percent of Stock Proposed To Be Authorized for Take
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Maximum number                                                                 Percent of
                                                                 of animals     Maximum total   Proposed take    Proposed take      Total       stock
                           Species                               expected to     days of in-      by Level A       by Level B     proposed     proposed
                                                                  occur/day    water work \1\     harassment       harassment       take       for take
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor Seal..................................................              11              14                0              154         154         0.49
California Sea Lion..........................................              15              14                0              210         210        0.082
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor Seal..................................................              11              98           \2\ 74            1,078       1,152         3.72
California Sea Lion..........................................              15              98                0            1,470       1,470         0.57
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Includes potential temporary trestle installation/removal.
\2\ Assumes a maximum of 2 harbor seals sighted per day that may be impacted and 37 days of impact pile driving.

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. 
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.

Shutdown Zones

    Prior to commencement of in-water construction activities, the City 
would establish shutdown zones for all activities. The purpose of a 
shutdown zone is 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). During all in-
water construction activities, the City will implement a standard 
minimum 10 m (32.8 ft) shutdown zone. If a marine mammal enters the 
shutdown zone, in-water activities would be stopped until visual 
confirmation that the animal has left the zone of the animal is not 
sighted for 15 minutes.
    All marine mammals will be monitored in the Level B harassment 
zones and throughout the area as far as visual monitoring can take 
place. If a marine mammal enters the Level B harassment zone, in-water 
activities will continue and the animal's presence within the estimated 
harassment zone will be documented. Pile driving activity must be 
halted upon observation of either a species for which incidental take 
is not authorized or a species for which incidental take has been 
authorized but the authorized number of takes has been met, entering or 
within the harassment zone.

[[Page 12330]]



                              Table 10--Shutdown Zones and Level B Harassment Zones
----------------------------------------------------------------------------------------------------------------
                                                                     Minimum shutdown zone (m)        Level B
                   Pile size, type, and method                   --------------------------------   harassment
                                                                      Phocid          Otariid        zone (m)
----------------------------------------------------------------------------------------------------------------
                                                     Year 1
----------------------------------------------------------------------------------------------------------------
14'' p/c concrete vibratory removal.............................              10              10           7,356
----------------------------------------------------------------------------------------------------------------
                                                     Year 2
----------------------------------------------------------------------------------------------------------------
14'' p/c concrete vibratory install/removal.....................              10              10           7,356
14'' p/c concrete impact install................................                                              46
30'' steel pile in CISS impact install..........................                                           1,000
30'' steel pile in CISS vibratory install.......................                                           3,981
20'' steel pile vibratory install...............................                                           1,848
----------------------------------------------------------------------------------------------------------------

Protected Species Observers

    The placement of protected species observers (PSOs) during all pile 
driving activities (described in the Proposed Monitoring and Reporting 
section) would ensure that the entire shutdown zone is visible. Should 
environmental conditions deteriorate such that the entire shutdown zone 
would not be visible (i.e., fog, heavy rain), pile driving would be 
delayed until the PSO is confident marine mammals within the shutdown 
zone could be detected.

Pre-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 zone and monitoring zones for a period of 30 
minutes. The shutdown zone would be considered cleared when a marine 
mammal has not been observed within the zone for that 30-minute period. 
If a marine mammal is observed within the shutdown zones listed in 
Table 10, pile driving activity would be delayed or halted. If work 
ceases for more than 30 minutes, the pre-activity monitoring of the 
shutdown zones would commence. A determination that the shutdown zone 
is clear must be made during a period of good visibility (i.e., the 
entire shutdown zone and surrounding waters must be visible to the 
naked eye).
    Pre-construction monitoring will also take place over the course of 
at least 5 days before commencing in-water construction activities. The 
purpose of this monitoring effort would be to update occurrence 
information on marine mammals in the project area. Specifically, this 
monitoring would cover a period of at least 1 week for 4 hours each 
day.

Soft-Start Procedures

    Soft-start procedures 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, 
followed by a 30-second waiting period, then two subsequent reduced-
energy strike sets. 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.
    Based on our evaluation of the City'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.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present 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 would be 
conducted by PSOs meeting the following NMFS requirements:
     Independent PSOs (i.e., not construction personnel) who 
have no other assigned tasks during monitoring periods would be used;
     At least one PSO would have prior experience performing 
the duties of a PSO during construction activity

[[Page 12331]]

pursuant to a NMFS-issued incidental take authorization;
     Other PSOs may substitute education (degree in biological 
science or related field) or training for experience; and
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator would be designated. The lead 
observer would be required to have prior experience working as a marine 
mammal observer during construction.
    PSOs would have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    The City would have at least one PSO stationed at the best possible 
vantage points in the project area to monitor during all pile driving 
activities. If a PSO sights a marine mammal in the shutdown zone, the 
PSO should notify the equipment operator to shut down. The PSO will let 
the contractor know when activities can re-commence. Additional PSOs 
may be employed during periods of low or obstructed visibility to 
ensure the entirety of the shutdown zones are monitored. A marine 
mammal monitoring plan will be developed and submitted to NMFS for 
approval prior to commencing in-water construction activities.

Reporting

    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving activities for each 
IHA, 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 report would include an overall 
description of work completed, a narrative regarding marine mammal 
sightings, and associated PSO datasheets. Specifically, the report 
would include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including: (a) How many and what type of piles were 
driven or removed and the method (i.e., impact or vibratory); and (b) 
the total duration of time for each pile (vibratory driving) or number 
of strikes for each pile (impact driving);
     PSO locations during marine mammal monitoring; and
     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.
    PSOs would record all incidents of marine mammal occurrence, 
regardless of distance from activity, and would document any behavioral 
reactions in concert with distance from piles being driven or removed. 
Specifically, PSOs will record the following:
     Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting;
     Time of sighting;
     Identification of the animal(s) (e.g., genus/species, 
lowest possible taxonomic level, or unidentified), PSO confidence in 
identification, and the composition of the group if there is a mix of 
species;
     Distance and location of each observed marine mammal 
relative to the pile being driven or hole being drilled for each 
sighting;
     Estimated number of animals (min/max/best estimate);
     Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
     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, or flushing);
     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 specified 
actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    If no comments are received from NMFS within 30 days, the draft 
report would constitute the final reports. If comments are received, a 
final report addressing NMFS' comments would be required to be 
submitted within 30 days after receipt of comments. All PSO datasheets 
and/or raw sighting data 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 City of Santa Cruz would 
report the incident to the Office of Protected Resources (OPR), NMFS 
([email protected]) and to the West Coast regional 
stranding network (866-767-6114) as soon as feasible. If the death or 
injury was clearly caused by the specified activity, the City of Santa 
Cruz 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 the IHAs. The City of Santa Cruz would not resume their activities 
until notified by NMFS.
    The report would 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''

[[Page 12332]]

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 
California sea lions and harbor seals, given that the anticipated 
effects of this activity on these different marine mammal stocks are 
expected to be similar. Where there are meaningful differences between 
these species, in anticipated individual responses to activities, 
impact of expected take on the population due to differences in 
population status, or impacts on habitat, they are described 
independently in the analysis below.
    Pile installation and removal activities have the potential to 
disturb or displace marine mammals. Specifically, the project 
activities may result in take, in the form of Level B harassment and, 
for harbor seals, Level A harassment, from underwater sounds generated 
from impact pile installation and vibratory pile installation and 
removal activities. Potential takes could occur if individuals move 
into the ensonified zones when these activities are underway.
    No serious injury or mortality would be 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 
California sea lions due to the application of planned mitigation 
measures, such as shutdown zones that encompass the Level A harassment 
zones for this species. The potential for harassment would be minimized 
through the construction method and the implementation of the planned 
mitigation measures (see Proposed Mitigation section).
    Take by Level A harassment is proposed for harbor seals during Year 
2 as the Level A harassment zone for impact pile driving exceeds the 
size of the shutdown zone for this activity. Therefore, there is the 
possibility that an animal could enter a Level A harassment zone 
without being detected, and remain within that zone for a duration long 
enough to incur PTS. 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 for species is very low. For California sea lions, NMFS 
anticipates and proposes to authorize no Level A harassment take over 
the duration of the City's planned activities; for harbor seals, NMFS 
proposes to authorize no take by Level A harassment in Year 1 and no 
more than 74 takes by Level A harassment in Year 2. If hearing 
impairment occurs, it is most likely that the affected animal would 
lose only a few decibels 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.
    The takes from Level B harassment would be due to potential 
behavioral disturbance. On the basis of reports in the literature as 
well as monitoring from other similar activities, effects 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; NAVFAC SW, 2018). 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. 
Marine mammals could also experience TTS if they move into the Level B 
monitoring zone. TTS is a temporary loss of hearing sensitivity when 
exposed to loud sound, and the hearing threshold is expected to recover 
completely within minutes to hours. Thus, it is not considered an 
injury. While TTS could occur, it is not considered a likely outcome of 
this activity. 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 potential for 
harassment is minimized through construction methods and the 
implementation of planned mitigation strategies (see Proposed 
Mitigation section).
    Anticipated and authorized takes are expected to be limited to 
short-term Level A (potential PTS) and Level B harassment (behavioral 
disturbance) as construction activities will occur over the course of 
14 days in Year 1 and 98 days in Year 2.
    Take would also occur within a limited, confined area of each 
stock's range. Level A and Level B harassment would be reduced to the 
level of least practicable adverse impact through use of mitigation 
measures described herein. Further, the amount of take authorized is 
extremely small when compared to stock abundance.
    No marine mammal stocks for which incidental take authorization is 
proposed are listed as threatened or endangered under the ESA or 
determined to be strategic or depleted under the MMPA. The relatively 
low marine mammal occurrences in the area, small shutdown zones, and 
proposed monitoring make injury takes of marine mammals unlikely. The 
shutdown zones would be thoroughly monitored before the proposed pile 
installation or removal begins, and construction activities would be 
postponed if a marine mammal is sighted within the shutdown zone. There 
is a high likelihood that marine mammals would be detected by trained 
observers under environmental conditions described for the proposed 
project. Therefore, the proposed mitigation and monitoring measures are 
expected to reduce the amount and intensity for Level A and Level B 
behavioral harassment. Furthermore, the pile installation and removal 
activities analyzed here are similar to, or less impactful than, 
numerous construction activities conducted in other similar locations 
which have occurred with no reported injuries or mortality to marine 
mammals, and no known long-term adverse consequences from behavioral 
harassment.

[[Page 12333]]

    The proposed project is not expected to have significant adverse 
effects on marine mammal habitat. There are no Biologically Important 
Areas or ESA-designated critical habitat within the project area, and 
the proposed activities would not permanently modify existing marine 
mammal habitat. The activities may cause fish to leave the area 
temporarily. This could impact marine mammals' foraging opportunities 
in a limited portion of the foraging range, however, due to the short 
duration of activities and the relatively small area of affected 
habitat, the impacts to marine mammal habitat are not expected to cause 
significant or long-term negative consequences.
    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 reproduction or survival of any individual 
marine mammals, much less affect 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;
     No Level A harassment of California sea lions is proposed;
     The small Level A harassment takes of harbor seals 
proposed for authorization are expected to be of a small degree;
     The intensity of anticipated takes by Level B harassment 
is relatively low for all stocks. Level B harassment would primarily be 
in the form of behavioral disturbance, resulting in avoidance of the 
project areas around where pile driving or removal activities are 
occurring;
     Biologically important areas or critical habitat have not 
been identified within the project area;
     The lack of anticipated significant or long-term effects 
to marine mammal habitat;
     Effects on marine mammal prey species 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; and
     The efficacy of the mitigation measures in reducing the 
effects of the specified activities on all species and stocks.
    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 small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The instances of take NMFS proposes to authorize is below one-third 
of the estimated stock abundance for all impacted stocks (Table 9). (In 
fact, take of individuals is less than 4 percent of the abundance for 
all affected stocks.) The number of animals that we expect to authorize 
to be taken would be considered small relative to the relevant stocks 
or populations, even if each estimated take occurred to a new 
individual. Furthermore, these takes are likely to only occur within a 
small portion of the each stock's range and the likelihood that each 
take would occur to a new individual is low.
    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

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks would 
not have an unmitigable adverse impact on the availability of such 
species or stocks for taking for subsistence purposes.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species.
    No incidental take of ESA-listed species is proposed for 
authorization or expected to result from this activity. Therefore, NMFS 
has determined that formal consultation under section 7 of the ESA is 
not required for this action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the City for conducting pile driving activities in the 
Harbor in July 2023 and July through September 2024, 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 
construction. 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 
Activities section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activities section of this 
notice would not be completed by the time the IHA expires and a renewal

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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: February 21, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-03910 Filed 2-24-23; 8:45 am]
BILLING CODE 3510-22-P