[Federal Register Volume 86, Number 50 (Wednesday, March 17, 2021)]
[Notices]
[Pages 14579-14595]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-05512]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XA199]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Army Corps of Engineers Port San 
Luis Breakwater Repair Project, Avila Beach, 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 Army Corps of Engineers 
(ACOE) for authorization to take marine mammals incidental to the Port 
San Luis Breakwater Repair Project in Avila Beach, California. Pursuant 
to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments 
on its proposal to issue an incidental harassment authorization (IHA) 
to incidentally take marine mammals during the specified activities. 
NMFS is also requesting comments on a possible one-year renewal that 
could be issued under certain circumstances and if all requirements are 
met, as described in Request for Public Comments at the end of this 
notice. NMFS will consider public comments prior to making any final 
decision on the issuance of the requested MMPA authorizations and 
agency responses will be summarized in the final notice of our 
decision.

DATES: Comments and information must be received no later than April 
16, 2021.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Electronic comments should be sent 
to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at https://www.fisheries.noaa.gov/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: Dwayne Meadows, Ph.D., 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://

[[Page 14580]]

www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-
marine-mammal-protection-act. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

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

National Environmental Policy Act

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

Summary of Request

    On March 13, 2020, NMFS received an application from the ACOE 
requesting an IHA to take small numbers of three species of pinnipeds 
incidental to resetting and replacing stone and dredging associated 
with the San Luis Breakwater Repair Project. ACOE subsequently notified 
us that funding, workload and other issues led them to delay the 
project 1 year. A revised application was sent on February 18, 2021 and 
the application process was reinitiated. The application was deemed 
adequate and complete on March 1, 2021. ACOE's request is for take of a 
small number of three species of marine mammals by Level B harassment. 
Neither the ACOE nor NMFS expects serious injury or mortality to result 
from this activity and, therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    The project consists of the repair of a deteriorating breakwater at 
Port San Luis, California. The proposed project is required to protect 
Port San Luis Harbor and maintain safe navigability within the port. 
Repair work includes minor excavation of shoaled sediment (~15,000 
cubic yards (11,470 cubic meters)) adjacent to the leeward side of the 
breakwater to create adequate depths for barges and support boats to 
access the breakwater for the repair. Approximately 29,000 tons (26,310 
metric tons) of existing stone would need to be reset and 60,000 tons 
(54,430 metric tons) of new stone (stones range from 5 to 20 tons (4.5-
18.1 metric tons) each) would be placed to restore the most heavily 
damaged portion of the breakwater. The project is expected to take no 
more than 174 work days over 7 months. The sounds and visual 
disturbance from the work can result in take of marine mammals through 
behavioral harassment and/or auditory injury.

Dates and Duration

    The IHA will be valid April 1, 2022 through March 31, 2023. Due to 
the location of the breakwater, the work would be fully or partially 
exposed to open ocean wave conditions. Adverse wave and inclement 
winter weather conditions at the breakwater generally preclude safe 
working conditions during the months of November to March. Therefore, 
the analysis emphasizes conditions during the likely work window but 
considers that work could possibly occur anytime during the year in 
case work is not completed and decent weather days occur in late fall 
and winter.

Specific Geographic Region

    The project site is located on the central California Coast, 
approximately midway between Los Angeles and San Francisco, in San Luis 
Obispo County (Figure 1). An offshore rock formation on the seaward 
side of the breakwater's southern end absorbs direct wave energy and 
reduces the intensity of waves reaching the breakwater. This allows for 
manageable pinniped haulout locations on both the seaward and leeward 
sides of the breakwater in proximity to this rock. A small island 
called Smith Island is approximately 400 meters (m) (1312 feet) to the 
northwest of the breakwater and also attracts pinnipeds. Smith Island 
is also near some eelgrass remediation that is part of the project.
BILLING CODE 3510-22-P

[[Page 14581]]

[GRAPHIC] [TIFF OMITTED] TN17MR21.000

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    Port San Luis breakwater is approximately 2,400 feet (730 m) long 
and 20 feet (6 m) wide. Repair work would focus on the most heavily 
damaged 1,420 feet (430 m) at the seaward end of the breakwater. The 
footprint of the breakwater would not be changed, but the crest 
elevation would be raised 3 feet (1 m) from +13 feet Mean Lower Low 
Water (MLLW) to +16 feet MLLW for hydraulic stability, to accommodate 
larger armor stone, to meet design criteria, and to account for sea 
level rise. Repair work could potentially extend to the sea bed to 
ensure a stable slope and structural stability is maintained. Repair 
work construction activities would be limited to daylight hours 
(approximately 11 hours a day), 6 days a week.
    The sediment removal is the first phase of the project and would 
require one to 3 weeks. The excavated material would be side cast to an 
adjacent area from where it was removed. The sediment excavation 
requires a crane-equipped barge, possibly a scow, up to two tugboats, 
and two small craft support vessels. The crane on the barge will be 
outfitted with a clamshell bucket which will be lowered by the crane 
operator to the sea floor to excavate sediment. The crane will pivot 
around and place material in an adjacent area or into a scow for 
placement at a designated placement site within the vicinity.
    The major phase of the breakwater repair requires a crane-equipped 
barge, up to two barges carrying rock to be added to the breakwater, up 
to three tug boats, and three small craft support vessels. The work 
will consist of resetting of existing stone and placement of new stone 
on the breakwater structure. Dropping of armor stone is not permitted, 
but it should be expected that some stones may be accidentally dropped 
during placement. Stones would be carefully placed and interlocked with 
existing stones to maximize stability and minimize the intensity of 
sound due to stone placement. The crane on the barge will be outfitted 
with lifting tongs to reset existing stone and retrieve stones from the 
rock storage barge, and then place those stones on damaged sections of 
the jetties. A boat operator in a skiff, and a spotter on the jetty, 
would direct the operation of the crane in order to pick and place the 
stones. The picked stone must be able to match the dimensions of the 
voids along the jetty. Approximately 30 to 35 stones can be picked and 
placed per day.
    The small tugs help position the barge and other support vessels 
ferry equipment and crew back and forth from the shore, jetties, 
staging areas, and the crane and rock storage barges. Rock storage 
barges are typically towed in from an offsite quarry location (likely 
Pebbly Beach Quarry on Santa Catalina Island), and then anchored next 
to the crane-equipped barge. The rock storage

[[Page 14582]]

barges are expected to carry approximately 1,500 tons (1,360 metric 
tons) of stone per trip. Additional rock storage barges will be stored 
within a designated area within Port San Luis Harbor until they are 
needed. Approximately 40 rock storage barges/loads will be needed for 
this project.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 1 lists all species or stocks for which take is expected and 
proposed to be authorized for this action, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and ESA and potential biological removal (PBR), where known. 
For taxonomy, we follow Committee on Taxonomy (2019). PBR is defined by 
the MMPA as the maximum number of animals, not including natural 
mortalities, that may be removed from a marine mammal stock while 
allowing that stock to reach or maintain its optimum sustainable 
population (as described in NMFS's SARs). While no mortality is 
anticipated or authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. Pacific SARs and draft SARs (e.g., Carretta et al. 2019, 
2020).

                    Table 1--Species That Spatially Co-Occur With the Activity to the Degree That Take Is Reasonably Likely To Occur
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                                                                                         ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
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                                                         Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
 sea lions):
    California Sea Lion.............  Zalophus californianus.  United States..........  -, -, N             257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Steller Sea Lion................  Eumetopias jubatus.....  Eastern DPS............  -, -, N             43,210 (N/A, 43,201,        2,592        113
                                                                                                             2017).
Family Phocidae (earless seals):
    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 Potential Biological Removal (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-assessment-reports. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\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 mortality/serious injury (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.

    As indicated above, all three species (with three managed stocks) 
in Table 1 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur, and we have proposed 
authorizing it. All species that could potentially occur in the 
proposed survey areas are discussed in the IHA application. While gray 
whales, humpback whales, blue whales, killer whales, bottlenose and 
common dolphins, harbor porpoise, fur seal, and northern elephant seals 
have been sighted 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. None of 
the cetacean species would occur close enough to the breakwater to be 
exposed to the limited sound from the project, and as cetaceans they do 
not haul out where they would be exposed to the visual or in-air 
disturbance of the project. Surveys over multiple years (see below) 
have not recorded fur seals or northern elephant seals in the vicinity 
of the project so take is not requested for these species and they are 
not discussed further.

California Sea Lion

    California sea lions occur from Vancouver Island, British Columbia, 
to the southern tip of Baja California. They breed on the offshore 
islands of southern and central California from May through July (Heath 
and Perrin 2008). During the non-breeding season, adult and subadult 
males and 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 (Heath 
and Perrin 2008, Lowry and Forney 2005). Females and some juveniles 
tend to remain closer to rookeries (Antonelis et al. 1990, Melin et al. 
2008).
    Pupping occurs primarily on the California Channel Islands from 
late May until the end of June (Peterson and Bartholomew 1967). Weaning 
and mating occur in late spring and summer during the peak upwelling 
period (Bograd et al., 2009). After the mating season, adult males 
migrate northward to feeding areas as far away as the Gulf of Alaska 
(Lowry et al., 1992), and they remain away until spring (March-May), 
when they migrate back to the breeding colonies. Adult females 
generally remain south of Monterey Bay, California throughout the year, 
feeding

[[Page 14583]]

in coastal waters in the summer and offshore waters in the winter, 
alternating between foraging and nursing their pups on shore until the 
next pupping/breeding season (Melin and DeLong 2000; Melin et al. 
2008). Increasing sea-surface temperatures in the California Current 
negatively impact prey species availability and reduce survival rates 
(DeLong et al. 2017, Laake et al. 2018, Lowry et al. 1991, Melin et al. 
2008, 2010).
    California sea lions are common in Port San Luis year round where 
they are often hauled out on buoys, work docks, and the breakwater 
structure. The general distribution along the breakwater is influenced 
by direct wave energy against exposed breakwater segments. Generally 
the breakwater is utilized beginning in April extending through 
December, with greater densities observed hauled out at the south 
eastern end of the breakwater. In addition, greater densities were 
observed on the leeward side as opposed to the seaward side, except on 
the southeastern seaward side where some rocks provide protection 
depending on the prevailing current and wind.

Harbor Seal

    Harbor seals are found from Baja California to the eastern Aleutian 
Islands of Alaska (Harvey and Goley 2011). In California there are 
approximately 500 haulout sites along the mainland and on offshore 
islands, including intertidal sandbars, rocky shores, and beaches 
(Hanan 1996, Lowry et al. 2008). Harbor seals are central-place 
foragers (Orians and Pearson 1979) and tend to exhibit strong site 
fidelity within season and across years, generally forage close to 
haulout sites, and repeatedly visit specific foraging areas (Grigg et 
al. 2012, Suryan and Harvey 1998, Thompson et al. 1998).
    Harbor seals molt from May through June. Peak numbers of harbor 
seals haul out in central California during late May to early June, 
which coincides with the peak molt. During both pupping and molting 
seasons, the number of seals and the length of time hauled out per day 
increase, from an average of 7 hours per day to 10-12 hours (Harvey and 
Goley 2011, Huber et al. 2001, Stewart and Yochem 1994).
    Harbor seals tend to forage at night and haul out during the day 
with a peak in the afternoon between 1 p.m. and 4 p.m. (Grigg et al. 
2012, London et al. 2001, Stewart and Yochem 1994, Yochem et al. 1987). 
Tide levels affect the maximum number of seals hauled out, with the 
largest number of seals hauled out at low tide, but time of day and 
season have the greatest influence on haul-out behavior (Manugian et 
al. 2017, Patterson and Acevedo-Guti[eacute]rrez 2008, Stewart and 
Yochem 1994).
    Harbor seals have not been observed hauling out on the Port San 
Luis breakwater or work docks but they have been observed swimming in 
close proximity. They are also known to forage and rest in various 
small patch kelp beds of the inner harbor, ranging from 0.5 to 1.5 
miles (0.8 to 2.4 kilometers (km)) from the breakwater. The closest 
haulout to the project area is on Smith Island (Figure 1).
    Pupping occurs from March through May in central California (Codde 
and Allen 2018). Pups are weaned in four weeks, most by mid-June (Codde 
and Allen 2018). Harbor seals molt from June through July (Codde and 
Allen 2018) and breed between late March and June (Greig and Allen 
2015).

Steller Sea Lion

    Steller sea lions range along the North Pacific Rim from northern 
Japan to California, with centers of abundance and distribution in the 
Gulf of Alaska and Aleutian Islands. Large numbers of individuals 
widely disperse when not breeding (late May to early July) to access 
seasonally important prey resources (Muto et al., 2019). They were 
listed as threatened range-wide under the ESA on November 26, 1990 (55 
FR 49204). Steller sea lions were subsequently partitioned into the 
western and eastern Distinct Population Segments (DPSs; western and 
eastern stocks) in 1997 (62 FR 24345, May 5, 1997). The western DPS 
breeds on rookeries located west of 144[deg] W in Alaska and Russia, 
whereas the eastern DPS breeds on rookeries in southeast Alaska through 
California. The eastern DPS was delisted in 2013. The eastern DPS is 
the only population of Steller's sea lions thought to occur in the 
project area.
    In the southern end of its range (Channel Islands in southern 
California), Steller sea lions have declined considerably since the 
late 1930s and several rookeries and haulouts south of A[ntilde]o Nuevo 
Island have been abandoned (Carretta et al. 2019). Steller sea lions 
have been observed hauling out on the Port San Luis breakwater and work 
docks. Like the California sea lions, the general distribution of 
Steller sea lions when present along the breakwater is influenced by 
direct wave energy against exposed breakwater segments, the season, and 
day to day sea state conditions with the highest densities on the 
southeastern leeward end of the breakwater.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 2.

                                      Table 2--Marine Mammal Hearing Groups
                                                  [NMFS, 2018]
----------------------------------------------------------------------------------------------------------------
                       Hearing group                                     Generalized hearing range *
----------------------------------------------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales)...............  7 Hz to 35 kHz.

[[Page 14584]]

 
Mid-frequency (MF) cetaceans (dolphins, toothed whales,      150 Hz to 160 kHz.
 beaked whales, bottlenose whales).
High-frequency (HF) cetaceans (true porpoises, Kogia, river  275 Hz to 160 kHz.
 dolphins, cephalorhynchid, Lagenorhynchus cruciger & L.
 australis).
Phocid pinnipeds (PW) (underwater) (true seals)............  50 Hz to 86 kHz.
Otariid pinnipeds (OW) (underwater) (sea lions and fur       60 Hz to 39 kHz.
 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. 
Harbor seals are in the phocid group and the sea lions are classified 
as otariid pinnipeds.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species or 
stocks.
    The likely or possible impacts of the ACOE's proposed activity on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical and 
visual presence of the equipment, vessels, and personnel. Acoustic 
stressors include effects of heavy equipment operation, rock setting, 
and sediment movement. The effects of underwater and in-air noise and 
visual disturbance from the ACOE's proposed activities have the 
potential to result in Level B harassment of marine mammals in the 
action area.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far (ANSI 1994, 1995). The sound level of an area 
is defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., waves, wind, 
precipitation, earthquakes, ice, atmospheric sound), biological (e.g., 
sounds produced by marine mammals, fish, and invertebrates), and 
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project would 
include sediment removal and rock setting. The sounds produced by these 
activities fall into one of two general sound types: Impulsive and non-
impulsive. Impulsive sounds (e.g., explosions, gunshots, sonic booms, 
impact pile driving) are typically transient, brief (less than 1 
second), broadband, and consist of high peak sound pressure with rapid 
rise time and rapid decay (ANSI, 1986; NIOSH, 1998; ANSI, 2005; NMFS, 
2018). Non-impulsive sounds (e.g., machinery operations such as 
drilling or dredging, vibratory pile driving, and active sonar systems) 
can be broadband, narrowband or tonal, brief or prolonged (continuous 
or intermittent), and typically do not have the high peak sound 
pressure with 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 in 
Southall et al., 2007). There is likely to be some level of non-
impulsive sounds from the sediment removal and rock setting equipment 
activities. In addition there is likely to be some impulsive sounds 
from the setting or occasional accidental dropping of stones.

Acoustic Impacts

    Visual disturbance and the introduction of anthropogenic noise into 
the environment from rock setting is the primary means by which marine 
mammals may be harassed from the ACOE's specified activity. In general, 
animals exposed to natural or anthropogenic sound may experience 
physical and psychological effects, ranging in magnitude from none to 
severe (Southall et al., 2007). Generally, exposure to this 
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 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

[[Page 14585]]

functions such as communication and predator and prey detection. The 
effects of noise on marine mammals are dependent on several factors, 
including, but not limited to, sound type (e.g., impulsive vs. non-
impulsive), the species, age and sex class (e.g., adult male vs. mom 
with calf), duration of exposure, the distance between the activity and 
the animal, received levels, behavior at time of exposure, and previous 
history with exposure (Wartzok et al., 2004; Southall et al., 2007). 
Here we discuss physical auditory effects (threshold shifts) followed 
by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS 2018). Available data from 
humans and other terrestrial mammals indicate that a 40 dB threshold 
shift approximates PTS onset (see Ward et al., 1958, 1959; Ward, 1960; 
Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson and 
Hu, 2008). PTS levels for marine mammals are estimates, with the 
exception of a single study unintentionally inducing PTS in a harbor 
seal (Kastak et al., 2008), there are no empirical data measuring PTS 
in marine mammals, largely due to the fact that, for various ethical 
reasons, experiments involving anthropogenic noise exposure at levels 
inducing PTS are not typically pursued or authorized (NMFS, 2018).
    Temporary Threshold Shift (TTS)--A temporary, reversible increase 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2018). Based on data from cetacean TTS measurements (see 
Southall et al., 2007), a TTS of 6 dB is considered the minimum 
threshold shift clearly larger than any day-to-day or session-to-
session variation in a subject's normal hearing ability (Schlundt et 
al., 2000; Finneran et al., 2000, 2002). As described in Finneran 
(2016), marine mammal studies have shown the amount of TTS increases 
with cumulative sound exposure level (SELcum) in an 
accelerating fashion: At low exposures with lower SELcum, 
the amount of TTS is typically small and the growth curves have shallow 
slopes. At exposures with higher SELcum, the growth curves 
become steeper and approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
masking, below). For example, a marine mammal may be able to readily 
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during a time when the animal 
is traveling through the open ocean, where ambient noise is lower and 
there are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts. We note that reduced hearing sensitivity as 
a simple function of aging has been observed in marine mammals, as well 
as humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor 
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis)) 
and five species of pinnipeds exposed to a limited number of sound 
sources (i.e., mostly tones and octave-band noise) in laboratory 
settings (Finneran, 2015). TTS was not observed in trained spotted 
(Phoca largha) and ringed (Pusa hispida) seals exposed to impulsive 
noise at levels matching previous predictions of TTS onset (Reichmuth 
et al., 2016). In general, harbor seals and harbor porpoises have a 
lower TTS onset than other measured pinniped or cetacean species 
(Finneran, 2015). Additionally, the existing marine mammal TTS data 
come from a limited number of individuals within these species. No data 
are available on noise-induced hearing loss for mysticetes. For 
summaries of data on TTS in marine mammals or for further discussion of 
TTS onset thresholds, please see Southall et al. (2007), Finneran and 
Jenkins (2012), Finneran (2015), and Table 5 in NMFS (2018).
    Resetting rocks and moving sediments are intermittent activities, 
especially for the loudest noises. There would likely be pauses in 
activities producing the sound during each day. Given these pauses and 
that many marine mammals are likely moving through the action area and 
not remaining for extended periods of time, the potential for TS 
declines.
    Behavioral Harassment--Exposure to noise from the project also has 
the potential to behaviorally disturb marine mammals. Available studies 
show wide variation in response to in-air and 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 a sound by changing 
its behavior or moving a small distance, the impacts of the change are 
unlikely to be significant to the individual, let alone the stock or 
population. However, if a sound source displaces marine mammals from an 
important feeding or breeding area for a prolonged period, impacts on 
individuals and populations could be significant (e.g., Lusseau and 
Bejder, 2007; Weilgart, 2007; NRC, 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006) or in the worst cases stampede en 
masse towards the water. 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

[[Page 14586]]

maturity, experience, current activity, reproductive state, auditory 
sensitivity, time of day), as well as the interplay between factors 
(e.g., Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 
2007; Weilgart, 2007; Archer et al., 2010). Behavioral reactions can 
vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
In general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. Please see Appendices B and C of Southall et 
al. (2007) for a review of studies involving marine mammal behavioral 
responses to sound.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle 1950; Moberg 
2000). In many cases, an animal's first and sometimes most economical 
(in terms of energetic costs) response is behavioral avoidance of the 
potential stressor. Autonomic nervous system responses to stress 
typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg 1987; Blecha 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker 2000; Romano 
et al., 2002b) and, more rarely, studied in wild populations (e.g., 
Romano et al., 2002a). For example, Rolland et al. (2012) found that 
noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003), however 
distress is an unlikely result of this project based on observations of 
marine mammals during previous, similar projects in the area.
    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 
California coast area contains active commercial shipping, cruise ship 
and ferry operations, as well as numerous recreational and other 
commercial vessels; therefore, background sound levels in the area are 
already elevated.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with the sediment 
removal and rock setting that have the potential to cause behavioral 
harassment, depending on their distance from the construction 
activities. Cetaceans are not expected to be exposed to airborne sounds 
that would result in harassment as defined under the MMPA.
    Airborne noise would primarily be an issue for pinnipeds that are 
swimming or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. We recognize that 
pinnipeds in the water could also be exposed to airborne sound that may 
result in behavioral harassment when looking with their

[[Page 14587]]

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.

Visual Disturbance

    Pinnipeds that occur near the project site could be exposed to 
visual disturbance associated with the sediment removal and rock 
setting activities that have the potential to cause behavioral 
harassment, depending on their sensitivity and distance from the 
construction activities. Cetaceans are not expected to be exposed to 
airborne visual disturbance that would result in harassment as defined 
under the MMPA.
    Available studies show wide variation in response to in-air visual 
disturbance, therefore it is difficult to predict specifically how any 
given activity might affect pinnipeds perceiving the signal. If a 
pinniped does react briefly to visual disturbance 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. Since the construction work will not affect the entire 
length of the breakwater at any time the animals may simply move to 
other parts of the breakwater or nearby haulout locations. Some degree 
of habituation is possible. Monitoring data from the project will help 
ascertain these effects for similar future projects (see Proposed 
Monitoring and Reporting section below).
    California sea lions and northern elephant seals have been observed 
as less sensitive to visual stimuli than harbor seals. For example, 
monitoring of pinniped disturbance as a result of abalone research in 
the Channel Islands showed that while harbor seals flushed at a rate of 
69 percent, California sea lions flushed at a rate of only 21 percent. 
The rate for elephant seals declined to 0.1 percent (VanBlaricom 2010). 
For intertidal researchers the take rate for harbor seals was 40 
percent, while for California sea lions and northern elephant seals it 
was 24 and 19 percent, respectively (PISCO 2019).
    Construction activities related to estuary management and marsh 
restoration, including heavy equipment operation, sediment removal, and 
other activities, has also resulted in take of pinnipeds (Sonoma County 
Water Agency 2019, California Department of Fish and Wildlife 2018).
    Small and large vessels are also known to affect pinnipeds. Henry 
and Hammil (2001) measured the impacts of small boats (i.e., kayaks, 
canoes, motorboats and sailboats) on harbor seal haulout behavior in 
Metis Bay, Quebec, Canada. The most frequent disturbances were caused 
by lower speed, lingering kayaks, and canoes (33.3 percent) as opposed 
to motorboats (27.8 percent) conducting high-speed passes. The seal's 
flight reactions could be linked to a surprise disturbance factor by 
kayaks and canoes, which approach slowly, quietly, and low on the 
water. However, the authors note that once the animals were disturbed, 
there did not appear to be any significant lingering effect on the 
recovery of numbers to their pre-disturbance levels.
    Acevedo-Gutierrez and Johnson (2007) evaluated the efficacy of 
buffer zones for watercraft around harbor seal haul-out sites on Yellow 
Island, Washington. The authors estimated the minimum distance between 
the vessels and the haul-out sites; categorized the vessel types; and 
evaluated seal responses to the disturbances. During the course of the 
study the authors recorded 14 human-related disturbances that were 
associated with stopped powerboats and kayaks. During these events, 
hauled out seals became noticeably active and moved into the water. The 
authors note that the seals were unaffected by passing powerboats, even 
those approaching as close as 128 feet (39 m), possibly indicating that 
the animals had become tolerant of the brief presence of the vessels 
and ignored them. The authors reported that on average, the seals 
quickly recovered from the disturbances and returned to the haul-out 
site in 60 minutes or less.
    The potential for striking marine mammals is a concern with vessel 
traffic. Typically, the reasons for vessel strikes are fast transit 
speeds, lack of maneuverability, or not seeing the animal because the 
boat is so large. The ACOE will access project areas at slow transit 
speeds, avoiding close approaches to the breakwater unless necessary, 
minimizing any chance of an accidental strike.
    The available evidence thus suggests the construction and vessel 
activities of the work on Port San Luis harbor have the potential for 
short-term Level B behavioral harassment, but not more serious effects.

Marine Mammal Habitat Effects

    The ACOE's construction activities could have localized, temporary 
impacts on marine mammal habitat and their prey by increasing in-water 
sound pressure levels and slightly decreasing water quality. Increased 
noise levels may affect acoustic habitat (see masking discussion above) 
and adversely affect marine mammal prey in the vicinity of the project 
area (see discussion below). During project work, elevated levels of 
underwater noise would ensonify Port San Luis Harbor where both fishes 
and mammals occur and could affect foraging success. Additionally, 
marine mammals may avoid the area during construction, however, 
displacement due to noise is expected to be temporary and is not 
expected to result in long-term effects to the individuals or 
populations. Construction activities are of short duration, produce 
relatively quiet in-water noise levels (see below), and would likely 
have temporary impacts on 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 sediment 
is removed or redeposited. Increases in turbidity detectable above 
background levels are usually confined from 100 to 500 feet from the 
crane-equipped barge depending on sediment character and tidal current 
conditions (Merkel and Associates 2010). Sediment adjacent to the PSL 
breakwater is expected to be characterized as sands, which fall out of 
the water column quickly. Suspended solid concentrations would likely 
return to background levels within an hour to 24 hours after excavation 
ceases (Merkel and Associates 2010). Cetaceans are not expected to be 
close enough to the activities to experience effects of turbidity, and 
any pinnipeds could avoid localized areas of turbidity. 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 project is relatively small 
compared to the available habitat (e.g., most of the impacted area is 
immediately adjacent to the breakwater and in the area where sediment 
is deposited of the bay and does not include any Biologically Important 
Areas). Extensive Pacific eelgrass (Zostera pacifica) beds are located 
throughout Port San Luis Harbor. Essential Fish Habitat mitigation 
under the Magnuson Stevens Act is a required part of the project for 
impacts to nearby eelgrass beds. The area is highly influenced by 
anthropogenic activities. The total

[[Page 14588]]

seafloor area affected is a very small area compared to the vast 
foraging area available to marine mammals in the area. At best, the 
impact area provides marginal foraging habitat for marine mammals and 
fish, while the new breakwater rocks would provide substrate for 
invertebrate prey to settle on. Furthermore, construction activity at 
the project site would not obstruct 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 avoidance of this area after construction stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity.
    In-water Construction Effects on Potential Prey--Sound may affect 
marine mammals through impacts on the abundance, behavior, or 
distribution of prey species (e.g., crustaceans, cephalopods, fish, 
zooplankton). Marine mammal prey varies by species, season, and 
location. 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, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). Several studies have demonstrated that impulse sounds might 
affect the distribution and behavior of some fishes, potentially 
impacting foraging opportunities or increasing energetic costs (e.g., 
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 
1992; Santulli et al., 1999; Paxton et al., 2017). However, some 
studies have shown no or slight reaction to impulse sounds (e.g., Pena 
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott 
et al., 2012).
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours 
for one species. Impacts would be most severe when the individual fish 
is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    The most likely impact to fish from 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.
    Construction activities, in the form of increased turbidity, have 
the potential to adversely affect fishes and invertebrates in the 
project area. Increased turbidity is expected to occur in the immediate 
vicinity of construction activities (see above). However, suspended 
sediments and particulates are expected to dissipate quickly. Given the 
limited area affected, high tidal dilution rates, and ability to avoid 
turbidity any effects on fish are expected to be minor or negligible. 
Some marine populations, particularly benthic organisms, would be 
destroyed by, or have filter-feeding or respiratory structures damaged 
by, the excavation of sediment, but are expected to recolonize the area 
once excavation of sediment has ceased (Merkel and Associates 2010).
    In summary, given the short daily duration of sound and visual 
disturbance associated with individual rock setting events and the 
relatively small areas being affected, construction activities 
associated with the proposed action are not likely to have a permanent, 
adverse effect on any fish habitat, or populations of fish species. Any 
behavioral avoidance by fish of the disturbed area would still leave 
significantly large areas of fish and marine mammal foraging habitat in 
the nearby vicinity. Thus, we conclude that impacts of the specified 
activity are not likely to have more than short-term adverse effects on 
any prey habitat or populations of prey species. Further, any impacts 
to marine mammal habitat are not expected to result in significant or 
long-term consequences for individual marine mammals, or to contribute 
to adverse impacts on their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of the acoustic source (i.e., rock setting) and visual disturbance has 
the potential to result in disruption of behavioral patterns for 
individual marine mammals. Based on the nature of the activity, Level A 
harassment is neither anticipated nor proposed to be authorized. The 
proposed mitigation and monitoring measures are expected to minimize 
the severity of the taking to the extent practicable.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds

[[Page 14589]]

above which NMFS believes the best available science indicates marine 
mammals will be behaviorally harassed or incur some degree of permanent 
hearing impairment; (2) the area or volume of water that will be 
ensonified above these levels in a day; (3) the density or occurrence 
of marine mammals within these ensonified areas; and, (4) and the 
number of days of activities. We note that while these basic factors 
can contribute to a basic calculation to provide an initial prediction 
of takes, additional information that can qualitatively inform take 
estimates is also sometimes available (e.g., previous monitoring 
results or average group size). Due to the lack of marine mammal 
density for some species, NMFS relied on local occurrence data and 
group size to estimate take. For activities like this with visual 
disturbance impacts we must also estimate the area or space within 
which harassment is likely to occur. Below, we describe the factors 
considered here in more detail and present the proposed take estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B harassment) or to incur PTS 
of some degree (equated to Level A harassment). Thresholds have also 
been developed identifying the received level of in-air sound above 
which exposed pinnipeds would likely be behaviorally harassed.
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 microPascal ([mu]Pa) (root mean square 
(rms)) for continuous (e.g., vibratory pile-driving) and above 160 dB 
re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., impact pile 
driving) or intermittent (e.g., scientific sonar) sources. The ACOE's 
proposed activity includes the use of continuous (general construction 
equipment and machinery) and impulsive (rock setting) sources, and 
therefore the 120 and 160 dB re 1 [mu]Pa (rms) thresholds are 
applicable.
    For in-air sounds, NMFS predicts that harbor seals exposed above 
received levels of 90 dB re 20 [mu]Pa (rms) will be behaviorally 
harassed, and other pinnipeds will be harassed when exposed above 100 
dB re 20 [mu]Pa (rms).
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). The ACOE's activity includes the use of 
impulsive (rock setting) and non-impulsive (general construction) 
sources.
    These thresholds are provided in Table 3. The references, analysis, 
and methodology used in the development of the thresholds are described 
in NMFS 2018 Technical Guidance, which may be accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

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

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., rock setting and sediment 
removal).

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,

[[Page 14590]]

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 ACOE's proposed activity.
    In order to calculate distances to the Level A harassment and Level 
B harassment sound thresholds for this project, NMFS used acoustic 
monitoring data collected by the ACOE. In February 2019 a team of 
researchers from the ACOE Los Angeles District and Engineer Research 
and Development Center traveled to a breakwater repair project at the 
Port of Long Beach, CA to collect representative sound data in 
anticipation of the Port San Luis breakwater project. Maintenance 
activities on the Long Beach, CA breakwater provided near identical 
conditions to the proposed work activities at Port San Luis, but the 
Long Beach site has no marine mammals nearby. At Long Beach they 
collected in-air and in-water sound recordings from both the rock 
setting and other construction equipment sounds. They also recorded 
ambient sound data at San Luis Obispo, CA near the breakwater to be 
used as a baseline measurement for proposed repair work. The analysis 
of the sound files provided by the ACOE to determine source levels 
relevant to marine mammal exposures contained some methods that we did 
not entirely concur with, but our acoustics expert (Dr. Shane Guan) was 
able to determine from them that in-water noise would not exceed marine 
mammal thresholds beyond 10 m (33 feet) from the source. He was also 
able to determine that in-air noise would not exceed the pinniped in-
air thresholds at a distance greater than 100 m (328 feet) from the 
source.

Visual Disturbance

    During the above-mentioned acoustic surveys of the similar 
breakwater repair work at the Port of Long Beach pinnipeds maintained a 
minimum approximate 150 foot (46 m) distance from construction 
equipment and personnel (Natalie Martinez-Takeshita, ACOE, personal 
communication 2020). Observations on a past breakwater repair project 
in Redondo Harbor, California showed that pinnipeds that flushed from 
distances up to 100 m (Natalie Martinez-Takeshita, ACOE, personal 
communication 2021). As noted above the construction barge could be up 
to 260 feet (80 m) long with activity occurring simultaneously at 
either end as well as the full reach of the crane. Based on the above 
information, we conservatively estimate a 200 m (660 ft) radius 
potential effect zone for Level B harassment of pinnipeds by visual 
disturbance. This equals or exceeds any effect radius from in-air 
noise. Given the breakwater is 2,400 feet (730 m) long, this means 
large portions of the breakwater should be undisturbed and available 
for animals to re-haulout on any given construction day.

Marine Mammal Occurrence and Take Calculation and Estimation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations. Take by Level B harassment is proposed for authorization 
and summarized in Table 6.
    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate.
    Merkel and Associates (2019) conducted three marine mammal surveys 
of the breakwater in 2018 as part of the preparation for this project. 
The surveys were in June, July and September. The focus was on other 
taxa besides marine mammals. Their most detailed marine mammal survey 
was in June when pinnipeds were identified to species level. They 
identified California sea lions and Steller sea lions hauled out on the 
breakwater, with 94 percent of the animals being California sea lions. 
Greater densities of pinnipeds were observed hauled out at the south 
eastern end of the breakwater, and the greatest densities were 
consistently observed at the most seaward end of the breakwater.
    In further anticipation of this project, the ACOE conducted 
additional approximately monthly marine mammal surveys, weather 
permitting, in the project area in 2019 to estimate breakwater 
abundance levels to use to estimate take. The 2019 surveys did not 
distinguish between California sea lions and Steller seals and assumed 
the Merkel and Associates (2019) determination that 94 percent of the 
animals were California sea lions and 6 percent were Steller sea lions 
applied during 2019 as well. While harbor seals were not observed 
hauled out on the breakwater, the ACOE did observe them hauled out at 
the low lying rocky benches of Smith Island (approximately 400 m (1,300 
feet) from the nearest repair area). They were also observed in the 
water adjacent to the breakwater on at least one occasion. No other 
marine mammal species were observed in the project area.

California Sea Lion and Steller Sea Lion

    The ACOE surveys from 2019 found that pinnipeds were present on the 
breakwater from April through December (Table 4), likely due to lower 
wave energy at those times. The highest number were present from June 
through September. We averaged the three highest surveys (bolded in the 
table) during the likely work period to determine that an average of 
321.33 animals were present daily during the spring to fall 
construction season. Using the results of Merkel and Associates (2019) 
June 2018 survey we estimated those 321.33 animals were comprised of 
302.05 California sea lions and 19.29 Steller sea lions per day. We 
used these numbers to estimate take for these two species for the 
project by multiplying these daily take estimates by the total number 
of work days (174). For California sea lions this is 302.05 x 174 = 
52,557 takes, and for Steller sea lions this is 19.28 x 174 = 3,355 
takes.

                   Table 4--ACOE 2019 Breakwater Pinniped Survey Results by Side of Breakwater
----------------------------------------------------------------------------------------------------------------
                           Survey date                                Leeward         Seaward          Total
----------------------------------------------------------------------------------------------------------------
1/30/2019.......................................................               0               0               0
1/31/2019.......................................................               0               0               0
2/1/2019........................................................               0               0               0
3/1/2019........................................................               0             (*)             * 0
3/24/2019.......................................................               0             (*)             * 0
3/30/2019.......................................................               0             (*)             * 0

[[Page 14591]]

 
3/31/2019.......................................................               0             (*)             * 0
4/1/2019........................................................               0             (*)             * 0
5/1/2019........................................................               0              18             18+
5/28/2019.......................................................             188             (*)             188
6/3/2019........................................................             182             115             297
7/29/2019.......................................................             166              25             191
8/27/2019.......................................................               0               1               1
9/25/2019.......................................................             326             150             476
11/6/2019.......................................................             398             (*)           * 398
12/5/2019.......................................................             113             (*)           * 113
12/28/2019......................................................               0               0            ** 0
----------------------------------------------------------------------------------------------------------------
* Seaward side of breakwater not surveyed because of sea state conditions, no pinnipeds expected to be hauled
  out during these times.
** No pinnipeds hauled out on breakwater, 3 observed swimming near head of breakwater.
Bold indicates months survey data was used to calculate the average abundance of pinnipeds on the PSL Breakwater
  per day.

Harbor Seal

    While harbor seals were not observed hauled out on the breakwater, 
they were observed hauled out at the low lying rocky benches of Smith 
Island and in the water near the breakwater during the ACOE 2019 
surveys. Estimated daily abundance for harbor seals was also calculated 
using the three highest abundance surveys from 2019 survey data from 
the likely construction season (late March through September, bolded in 
Table 5). The average abundance in the project area was 10.33 seals per 
day. We used this average and calculated total take for the project by 
multiplying by the total number of work days (174). For harbor seals 
this is 10.33 x 174 = 1,797 takes.

                                  Table 5--ACOE 2019 Harbor Seal Survey Results
----------------------------------------------------------------------------------------------------------------
                                               Swimming near    Hauled out at    Swimming near
                 Survey date                     breakwater      Smith Island     Smith Island        Total
----------------------------------------------------------------------------------------------------------------
1/30/19-2/1/19..............................                0               13          Several              ~16
3/1/2019....................................                0               15                0               15
3/24/2019...................................                1               14                3               18
5/1/2019....................................                0               10                0               10
5/28/2019...................................                0                2                1                3
6/3/2019....................................                0                0                0                0
7/29/2019...................................                0                0                0                0
8/27/2019...................................                0                0                0                0
9/25/2019...................................                0                0                0                0
11/6/2019...................................                0                0                0                0
12/5/2019...................................                0               25                0               25
12/28/2019..................................                0                1                1                2
----------------------------------------------------------------------------------------------------------------
Bold indicates months survey data was used to calculate the average abundance per day.

Summary

    The above-calculated take estimates are likely to be conservative 
as some animals may habituate to the project and regularly haul out on 
the parts of the breakwater where there is no construction activity, 
where construction activity has finished, or they may move to other 
nearby haulout locations. Moreover, because the main area of effect on 
any given day is no more than 300 m of breakwater length, the 
breakwater is much longer than this, most pinnipeds are concentrated at 
the far 200 m of the breakwater, and the project will begin at the 
landward end of the breakwater, far fewer animals will likely be taken 
in the early stages of the project.

   Table 6--Proposed Authorized Amount of Taking, by Level A Harassment and Level B Harassment, by Species and
                                       Stock and Percent of Take by Stock
----------------------------------------------------------------------------------------------------------------
                                                                          Authorized take
                             Species                             --------------------------------   Percent of
                                                                      Level B         Level A          stock
----------------------------------------------------------------------------------------------------------------
Harbor seal (Phoca vitulina) California Stock...................          52,557               0            20.4
California sea lion (Zalophus californianus) U.S. Stock.........           3,355               0             7.8
Steller sea lion (Eumetopias jubatus) Eastern DPS...............           1,797               0             6.6
----------------------------------------------------------------------------------------------------------------

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

[[Page 14592]]

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, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The following mitigation measures are proposed in the IHA:
     Monitoring must take place from 30 minutes prior to 
initiation of construction activity (i.e., pre-start clearance 
monitoring) through 30 minutes post-completion of construction 
activity.
     The ACOE must avoid direct physical interaction with 
marine mammals during construction activity. If a marine mammal comes 
within 10 meters of such activity, operations must cease and vessels 
must reduce speed to the minimum level required to maintain steerage 
and safe working conditions, as necessary to avoid direct physical 
interaction.
     Pre-start clearance monitoring must be conducted during 
periods of visibility sufficient for the lead Protected Species 
Observer (PSO) to determine the shutdown zones clear of marine mammals. 
Construction may commence when the determination is made.
     If construction is delayed or halted due to the presence 
of a marine mammal, the activity may not commence or resume until 
either the animal has voluntarily exited and been visually confirmed 
beyond the shutdown zone or 15 minutes have passed without re-detection 
of the animal.
     The Holder must use soft start techniques. Soft start 
requires contractors and equipment to slowly approach the work site 
creating a visual disturbance allowing animals in close proximity to 
construction activities a chance to leave the area prior to stone 
resetting or new stone placement. Contractors shall avoid walking or 
driving equipment through the seal haul-out. A soft start must be 
implemented at the start of each day's construction activity and at any 
time following cessation of activity for a period of 30 minutes or 
longer.
     Vessels would approach the breakwater perpendicular to the 
area they need to be as much as is feasible to minimize interactions 
with pinnipeds on or near the breakwater.
     The Holder must ensure that construction supervisors and 
crews, the monitoring team, and relevant ACOE staff are trained prior 
to the start of construction activity subject to this IHA, so that 
responsibilities, communication procedures, monitoring protocols, and 
operational procedures are clearly understood. New personnel joining 
during the project must be trained prior to commencing work.
     Construction 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 a 200 m 
Level B harassment zone.
     Construction work will start at the landward end of the 
breakwater as much as feasible.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable adverse impact on the affected species 
or stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring must be conducted in accordance with the 
Monitoring section of the application and Section 5 of the IHA. These 
observers must record all observations of marine mammals, regardless of 
distance from the construction activity. Marine mammal monitoring 
during construction activity must be conducted by NMFS-approved PSOs in 
a manner consistent with the following:

[[Page 14593]]

     Independent PSOs (i.e., not construction personnel) who 
have no other assigned tasks during monitoring periods must be used;
     At least one PSO must have prior experience performing the 
duties of a PSO during construction activity pursuant to a NMFS-issued 
incidental take authorization;
     Other PSOs may substitute education (degree in biological 
science or related field) or training for experience; and
     The ACOE must submit PSO Curriculum Vitae for approval by 
NMFS prior to the onset of pile driving.
    PSOs must have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    One PSO will be employed. PSO location will provide an unobstructed 
view of all water within the shutdown zone, and as much of the Level B 
harassment zones as possible. PSO location is as follows:
    (1) At the crane barge site or best vantage point practicable to 
monitor the shutdown zones; and
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after construction activities. In addition, observers shall 
record all incidents of marine mammal occurrence, regardless of 
distance from activity, and shall document any behavioral reactions in 
concert with distance from construction activity.

Reporting

    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 calendar days after the completion of pile driving and 
removal activities, or 60 calendar days prior to the requested issuance 
of any subsequent IHAs for construction activity at the same location, 
whichever comes first. A final report must be prepared and submitted 
within 30 days following resolution of any NMFS comments on the draft 
report. The report will include an overall description of work 
completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. All draft and final marine mammal and 
acoustic monitoring reports must be submitted to 
[email protected] and [email protected]. 
Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring.
     Construction activities occurring during each daily 
observation period, including how many and what type of rocks were set 
or reset and total duration of rock setting.
     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.
     PSO locations during marine mammal monitoring.
     Upon observation of a marine mammal, the following 
information:
    [cir] PSO who sighted the animal and PSO location and activity at 
time of sighting;
    [cir] Time of sighting;
    [cir] Identification of the animal (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;
    [cir] Distance and bearing of each marine mammal observed to the 
rock setting for each sighting (if rock setting was occurring at time 
of sighting);
    [cir] Estimated number of animals (min/max/best);
    [cir] Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
    [cir] Animal's closest point of approach and estimated time spent 
within the harassment zone;
    [cir] Number of disturbances, by species and age, according to a 
three-point scale of disturbance (see Table 7). Observations of 
disturbance Levels 2 and 3 must be recorded as takes. Description of 
any additional marine mammal behavioral observations (e.g., observed 
behaviors such as feeding or traveling;
     Detailed information about implementation of any 
mitigation (e.g., shutdowns and delays), a description of specific 
actions that ensued, and resulting changes in behavior of the animal, 
if any.
    The ACOE must submit all PSO datasheets and/or raw sighting data. 
If no comments are received from NMFS within 30 days, the draft final 
report will constitute the final report. If comments are received, a 
final report addressing NMFS comments must be submitted within 30 days 
after receipt of comments.

           Table 7--Levels of Pinniped Behavioral Disturbance
------------------------------------------------------------------------
         Level             Type of  response           Definition
------------------------------------------------------------------------
1.....................  Alert.................  Seal head orientation or
                                                 brief movement in
                                                 response to
                                                 disturbance, which may
                                                 include turning head
                                                 towards the
                                                 disturbance, craning
                                                 head and neck while
                                                 holding the body rigid
                                                 in a u-shaped position,
                                                 changing from a lying
                                                 to a sitting position,
                                                 or brief movement of
                                                 less than twice the
                                                 animal's body length.
2.....................  Movement..............  Movements in response to
                                                 the source of
                                                 disturbance, ranging
                                                 from short withdrawals
                                                 at least twice the
                                                 animal's body length to
                                                 longer retreats over
                                                 the beach, or if
                                                 already moving a change
                                                 of direction of greater
                                                 than 90 degrees.
3.....................  Flush.................  All retreats (flushes)
                                                 to the water.
------------------------------------------------------------------------


[[Page 14594]]

Reporting Injured or Dead Marine Mammals

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

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    To avoid repetition, this introductory discussion of our analyses 
applies to all of the species listed in Table 6, given that many of the 
anticipated effects of this project on different marine mammal stocks 
are expected to be relatively similar in nature. Construction 
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 from in-air sounds and visual disturbance generated 
from rock setting and sediment removal. Potential takes could occur if 
individuals are present in the ensonified or disturbance zone(s) when 
these activities are underway.
    The takes from Level B harassment would be due to potential 
behavioral disturbance or TTS. No mortality or PTS is anticipated given 
the nature of the activity and measures designed to minimize the 
possibility of injury to marine mammals. The potential for harassment 
is minimized through the construction method and the implementation of 
the planned mitigation measures (see Proposed Mitigation section).
    For all species and stocks, take would occur within a very limited, 
confined area (Port San Luis harbor) of any given stock's range. Level 
B harassment will be reduced to the level of least practicable adverse 
impact through use of mitigation measures described herein. Behavioral 
responses of marine mammals to construction at the project site, if 
any, are expected to be mild and temporary. Marine mammals within the 
Level B harassment zone may not show any visual cues they are disturbed 
by activities (as noted during modification to the Kodiak Ferry Dock 
and other construction projects near pinnipeds) or could become alert, 
avoid the area, leave the area, or display other mild responses that 
are not observable such as changes in vocalization patterns. Given the 
short duration of noise-generating activities per day, any harassment 
would be temporary. There are no other areas or times of known 
biological importance for any of the affected species.
    In addition, it is unlikely that minor noise effects in a small, 
localized area of habitat would have any effect on the stocks' ability 
to recover. In combination, we believe that these factors, as well as 
the available body of evidence from other similar activities, 
demonstrate that the potential effects of the specified activities will 
have only minor, short-term effects on individuals. The specified 
activities are not expected to impact rates of recruitment or survival 
and will therefore not result in population-level impacts.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality is anticipated or authorized.
     No Level A harassment is anticipated or authorized.
     No biologically important areas have been identified 
within the project area.
     For all species, the harbor is a very small and peripheral 
part of their range.
     The ACOE would implement mitigation measures such as 
vessel avoidance and slow down, proceeding from the low density to high 
density areas to increase habituation, soft-starts, and shut downs; and
     Monitoring reports from similar work have documented 
little to no effect on individuals of the same species impacted by the 
specified activities.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Section 101(a)(5)(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

[[Page 14595]]

as the temporal or spatial scale of the activities.
    The amount of take NMFS proposes to authorize of all species or 
stocks is below one third of the estimated stock abundance. These are 
all likely conservative estimates because they assume all takes are of 
different individual animals which is likely not the case as most 
stocks do not move in or out of the area frequently. Some individuals 
may return multiple times in a day, but PSOs would count them as 
separate takes if they cannot be individually identified.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. 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 (ESA)

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally, in this case with the West Coast Region 
Protected Resources Division Office, 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 ACOE to conduct the Port San Luis Breakwater Repair 
project in Avila Beach, California from April 1, 2022 through March 31, 
2023, provided the previously mentioned mitigation, monitoring, and 
reporting requirements are incorporated. A draft of the proposed IHA 
can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed Port 
San Luis Breakwater Repair project. We also request at this time 
comment on the potential renewal of this proposed IHA as described in 
the paragraph below. Please include with your comments any supporting 
data or literature citations to help inform decisions on the request 
for this IHA or a subsequent Renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time one-year Renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical, or nearly 
identical, activities as described in the Specified Activities section 
of this notice is planned or (2) the activities as described in the 
Specified Activities section of this notice would not be completed by 
the time the IHA expires and a Renewal would allow for completion of 
the activities beyond that described in the Dates and Duration section 
of this notice, provided all of the following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA);
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take); 
and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized; and
     Upon review of the request for Renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: March 12, 2021.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2021-05512 Filed 3-16-21; 8:45 am]
BILLING CODE 3510-22-P