[Federal Register Volume 86, Number 102 (Friday, May 28, 2021)]
[Notices]
[Pages 28768-28786]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-11333]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB120]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Army Corps of Engineers Debris Dock 
Replacement Project, Sausalito, 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 U.S. Army Corps of 
Engineers (ACOE) for authorization to take marine mammals incidental to 
the Debris Dock Replacement Project in Sausalito, 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 June 28, 
2021.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and 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://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

[[Page 28769]]

similar significance, and on the availability of the species or stocks 
for taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

National Environmental Policy Act

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

Summary of Request

    On March 17, 2021, NMFS received an application from ACOE 
requesting an IHA to take small numbers of seven species of marine 
mammals incidental to pile driving associated with the Debris Dock 
Replacement Project. The application was deemed adequate and complete 
on May 20, 2021. The ACOE's request is for take of a small number of 
these species by Level A or 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 purpose of the project is to replace the existing decaying dock 
and other onshore infrastructure used to move marine debris collected 
from San Francisco Bay onto land for disposal. The existing dock will 
be removed and replaced. The work will involve impact hammering 31 24-
inch diameter concrete deck support piles and 17 14-inch diameter 
timber fender piles for the replacement dock and removal of the decayed 
dock by cutting or otherwise removing 31 18-inch diameter concrete deck 
support piles and 17 14-inch diameter timber fender piles. This 
construction work will occur from September 1, 2021 through August 31, 
2022 and will take no more than 26 days of in-water pile work.
    The pile driving/removal can result in take of marine mammals from 
sound in the water which results in behavioral harassment or auditory 
injury.

Dates and Duration

    The work described here is scheduled for September 1, 2021 through 
August 31, 2022. In-water activities are planned for daylight hours 
only.

Specific Geographic Region

    The activities would occur in Richardson's Bay in north San 
Francisco Bay (Figure 1). The debris dock is situated adjacent to the 
ACOE Bay Model Facility in their San Francisco District Base Yard. The 
debris dock is neighbored by docks for long term mooring of private 
vessels to the north, and to the south there is a dock used for mooring 
of ACOE vessels and public use for storing kayaks. Nearby docks within 
approximately 0.15 miles (mi) (241 meters (m)) may serve as potential 
haulout locations for pinnipeds. Due to sinuosity of the shoreline, the 
haulout locations are not within line of site of the project. Pacific 
herring spawning events are known to take place within Richardson's 
Bay, which usually begin in late February. Endangered Species Act (ESA) 
listed Central California Coast Steelhead smolts are known to traverse 
Richardson's Bay in late February through April.
BILLING CODE 3510-22-P

[[Page 28770]]

[GRAPHIC] [TIFF OMITTED] TN28MY21.001

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    The purpose of the project is to replace the decaying seaward 
portion of a dock. Demolition of the existing debris dock would begin 
by first removing the fencing that borders the debris dock. The timber 
fender system would then be removed by pulling or cutting the 17 14-
inch diameter timber piles at approximately 2 feet below the mudline 
without dewatering. The piles would be hoisted out with a crane or 
tractor from land. The concrete deck would then be removed, along with 
a bulkhead wall (a vertical concrete retaining wall) which encloses the 
soil filled inner part of the dock. Temporary shoring (support beams) 
would be placed to fortify the bulkhead wall while soil is removed from 
the landward side, then the bulkhead wall would be demolished and 
removed. The bulkhead wall will be removed in similar fashion to the 
concrete deck, by breaking it apart with a tractor and hoisting it out 
with a crane. Riprap stones would then be removed and stored 
temporarily, for reuse with the finished dock. Finally, to complete 
demolition, the 31 18-inch square concrete piles that supported the 
concrete deck would be cut approximately 2 feet below the mudline 
without dewatering. They would then be removed by either a crane or 
tractor from land, such that no barge or other water borne vessel would 
be used in the demolition. The need to leave the in-situ portion of the 
piles in place, as opposed to removing them, stems from the risk of 
soil liquefaction and creating voids too close to the new pile 
locations which could cause the piles to shift their alignment or 
affect other parts of the debris dock structure which will not to be 
removed. Vibratory methods for removal and installation are thus not 
possible. Pile cutting will be accomplished with the use of either 
hydraulic underwater chainsaws or hydraulic pile clippers depending on 
the contractor's capability.
    Construction of the new dock would be in reverse of the demolition, 
by starting with the impact driving of 31 new octagonal concrete piles 
(24-inch diameter). Driving the piles until bedrock (approximately 80 
feet) would be accomplished with an impact

[[Page 28771]]

hammer. After the piles are driven, the 6-10 ton rip rap stones would 
be replaced and then a new bulkhead wall would be built. The deck of 
the debris dock would be built by cast-in-place pile caps, pre-cast 
concrete panels, and a cast-in-place concrete topping. The earthen fill 
behind the bulkhead retaining wall would then be backfilled. A new 
timber pile fender system with a total of 17 timber piles (14-inch 
diameter) would be installed. Timber piles would also be installed 
using an impact hammer. Pile driving equipment such as a crane will be 
deployed and operated from the landside from the inner part of the ACOE 
Base Yard for concrete piles, with timber piles being driven by 
equipment deployed on a barge. A bubble curtain to attenuate sound will 
be used for impact hammering of both timber and concrete piles. Pile 
driving and removal activities are summarized in Table 1. Finally, to 
complete the installation, the perimeter fencing, and other incidentals 
will be installed.
    A staging area will be used to store building supplies and 
construction equipment. The location of the staging area would be 
immediately adjacent to the debris dock portion that is to be replaced, 
within the ACOE Base Yard. The proposed project is currently scheduled 
to only take one construction season, with construction completed by 
December.
    In summary, the project period includes 10 days of pile removal and 
16 days of pile installation activities for which incidental take 
authorization is requested.

                                                 Table 1--Summary of Pile Driving and Removal Activities
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                                                                            Number of                                                        Duration
                  Method                             Pile type                piles         Minutes/ strikes per pile      Piles per day      (days)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cutting..................................  18-inch concrete............              31  5 min..........................              10               7
Cutting..................................  14-inch timber..............              17  5 min..........................              10               3
Impact Driving...........................  24-inch concrete............              31  1,000 strikes..................              10              10
Impact Driving...........................  14-inch timber..............              17  1,000 strikes..................              10               6
                                                                        --------------------------------------------------------------------------------
    Totals...............................  ............................              96  ...............................  ..............              26
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    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species with expected potential for occurrence in 
the project area in San Francisco Bay and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. For taxonomy, we follow Committee on 
Taxonomy (2020). 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., Caretta et al., 2020a 
and b).

                    Table 2--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/SI
                                                                                            \1\          abundance survey) \2\                   \3\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Eschrichtiidae:
    Gray Whale.....................  Eschrichtius robustus.  Eastern North Pacific.  -, -, N            26,960 (0.05, 25,849,           801          138
                                                                                                         2016).
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                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
    Bottlenose Dolphin.............  Tursiops truncatus....  California Coastal....  -, -, N            453 (0.06, 346, 2011).          2.7         >2.0
Family Phocoenidae (porpoises):
    Harbor porpoise................  Phocoena phocoena.....  San Francisco/Russian   -, -, N            9,886 (0.51, 2019)....           66            0
                                                              River.
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[[Page 28772]]

 
                                                         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).
    Northern fur seal..............  Callorhinus ursinus...  California............  -, D, N            14,050 (N/A, 7,524,             451          1.8
                                                                                                         2013).
                                                             Eastern North Pacific.  -, D, N            620,660 (0.2, 525,333,       11,295          399
                                                                                                         2016).
Family Phocidae (earless seals):
    Northern elephant seal.........  Mirounga                California Breeding...  -, -, N            179,000 (N/A, 81,368,         4,882          8.8
                                      angustirostris.                                                    2010).
    Harbor seal....................  Phoca vitulina........  California............  -, -, N            30,968 (N/A, 27,348,          1,641           43
                                                                                                         2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-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.

    Harbor seal, California sea lion, bottlenose dolphin and Harbor 
porpoise spatially co-occur with the activity to the degree that take 
is reasonably likely to occur, and we have proposed authorizing take of 
these species. For gray whale, northern fur seal and northern elephant 
seal, occurrence is such that take is possible, and we have proposed 
authorizing take of these species also. All species that could 
potentially occur in the proposed survey areas are included in the 
ACOE's IHA application (see application, Table 2). Humpback whales 
could potentially occur in the area. However the spatial and temporal 
occurrence of this species is very rare, the species is readily 
observed, and the applicant would shut down pie driving if humpback 
whales enter the project area. Thus take is not expected to occur, and 
they are not discussed further.

Bottlenose Dolphin

    The California coastal stock of common bottlenose dolphin is found 
within 0.6 mi (1 kilometer (km)) of shore (Defran and Weller, 1999) and 
occurs from northern Baja California, Mexico to Bodega Bay, CA. Their 
range has extended north over the last several decades with El 
Ni[ntilde]o events and increased ocean temperatures (Hansen and Defran, 
1990). Genetic studies have shown that no mixing occurs between the 
California coastal stock and the offshore common bottlenose dolphin 
stock (Lowther-Thieleking et al., 2015). Bottlenose dolphins are 
opportunistic foragers: Time of day, tidal state, and oceanographic 
habitat influence where they pursue prey (Hanson and Defran, 1993). 
Dive durations up to 15 minutes have been recorded for trained Navy 
bottlenose dolphins, (Ridgway et al., 1969), but typical dives are 
shallower and of a much shorter duration (approximately 30 ;et al., 
1999, Mate et al., 1995).
    Bottlenose dolphins began entering San Francisco Bay in 2010 
(Szczepaniak, 2013). They primarily occur in the western Central and 
South Bay, from the Golden Gate Bridge to Oyster Point and Redwood 
City. However, one individual has been regularly seen in San Francisco 
Bay since 2016 near the former Alameda Air Station (Perlman, 2017; W. 
Keener, pers. comm. 2017), and five animals were regularly seen in the 
summer and fall of 2018 in the same location (W. Keener, pers. comm. 
2019).

Harbor Porpoise

    Harbor porpoise occur along the US west coast from southern 
California to the Bering Sea (Carretta et al., 2019). They rarely occur 
in waters warmer than 62.6 degrees Fahrenheit (17 degrees Celsius; 
Read, 1990). The San Francisco-Russian River stock is found from 
Pescadero, 18 mi (30 km) south of the San Francisco Bay, to 99 mi (160 
km) north of the bay at Point Arena (Carretta et al., 2014). In most 
areas, harbor porpoise occur in small groups of just a few individuals.
    Harbor porpoise sightings in the San Francisco Bay declined in the 
1930's and were functionally extirpated shortly after. Harbor porpoise 
occur frequently outside San Francisco Bay and re-entered the bay 
beginning in 2008 (Stern et al., 2017). They now commonly occur year-
round within San Francisco Bay, primarily on the west and northwest 
side of the Central Bay near the Golden Gate Bridge, near Marin County, 
and near the city of San Francisco (Duffy 2015, Keener et al., 2012; 
Stern et al., 2017). In the summer of 2017 and 2018, mom-calf pairs and 
small groups (one to four individuals) were seen to the north and west 
of Treasure Island, and just south of Yerba Buena Island (Caltrans 
2018a, 2019; M. Schulze, pers. comm. 2019).
    Harbor porpoise must forage nearly continuously to meet their high 
metabolic needs (Wisniewska et al., 2016). They consume up to 550 small 
fish (1.2-3.9 in [3-10 cm]; e.g. anchovies) per hour at a nearly 90 
percent capture success rate (Wisniewska et al., 2016).

California Sea Lion

    California sea lions occur from Vancouver Island, British Columbia, 
to the southern tip of Baja California. Sea lions 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).
    California sea lions have occupied docks near Pier 39 in San 
Francisco, a few miles from the project area, since

[[Page 28773]]

1987. The highest number of sea lions recorded at Pier 39 was 1,701 
individuals in November 2009. Occurrence of sea lions here is typically 
lowest in June (during pupping and breeding seasons) and highest in 
August. Approximately 85 percent of the animals that haul out at this 
site are males, and no pupping has been observed here or at any other 
site in San Francisco Bay. Pier 39 is the only regularly used haulout 
site in the project vicinity, but sea lions occasionally haul out on 
human-made structures such as bridge piers, jetties, or navigation 
buoys (Riedman 1990).
    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 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).

Northern Fur Seal

    Two northern fur seal stocks may occur near San Francisco Bay: The 
California and Eastern North Pacific stocks. The California stock 
breeds and pups on the offshore islands of California, and forages off 
the California coast. The Eastern Pacific stock breeds and pups on 
islands in the North Pacific Ocean and Bering Sea, including the 
Aleutian Islands, Pribilof Islands, and Bogoslof Island, but females 
and juveniles move south to California waters to forage in the fall and 
winter months (Gelatt and Gentry, 2018). Breeding and pupping occur 
from mid- to late-May into July. Pups are weaned in September and move 
south to feed offshore California (Gentry, 1998).
    Both the California and Eastern North Pacific stocks forage in the 
offshore waters of California, but usually only sick or emaciated 
juvenile fur seals seasonally enter the bay. The Marine Mammal Center 
(TMMC) occasionally picks up stranded fur seals around Yerba Buena and 
Treasure Islands (NMFS, 2019b).

Northern Elephant Seal

    Northern elephant seals are common on California coastal mainland 
and island sites, where the species pups, breeds, rests, and molts. The 
largest rookeries are on San Nicolas and San Miguel islands in the 
northern Channel Islands. Near San Francisco Bay, elephant seals breed, 
molt, and haul out at A[ntilde]o Nuevo Island, the Farallon Islands, 
and Point Reyes National Seashore.
    Northern elephant seals haul out to give birth and breed from 
December through March. Pups remain onshore or in adjacent shallow 
water through May. Both sexes make two foraging migrations each year: 
One after breeding and the second after molting (Stewart, 1989; Stewart 
and DeLong, 1995). Adult females migrate to the central North Pacific 
to forage, and males migrate to the Gulf of Alaska to forage (Robinson 
et al., 2012). Pup mortality is high when they make the first trip to 
sea in May, and this period correlates with the time of most 
strandings. Young-of-the-year pups return in the late summer and fall 
to haul out at breeding rookeries and small haulout sites, but 
occasionally may make brief stops in San Francisco Bay.

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 the most common marine mammal species observed in 
the San Francisco Bay. Within the bay they primarily haul out on 
exposed rocky ledges and on sloughs in the southern San Francisco Bay. 
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 in San Francisco Bay forage mainly within 7 
mi (10 km) of their primary haulout site (Grigg et al., 2012), and 
often within just 1-3 mi (1-5 km; Torok, 1994). Depth, bottom relief, 
and prey abundance also influence foraging location (Grigg et al., 
2012).
    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).
    The closest haulout to the project area is on Yerba Buena Island. 
This haulout site has a daily range of zero to 109 harbor seals during 
fall months, with the highest numbers hauled out during afternoon low 
tides (Caltrans, 2004). The Golden Gate National Recreation Area 
contains a number of haul out areas in San Francisco Bay including 
Alcatraz Island and Point Bonita at the entrance to the bay (NPS, 
2016).
    Large concentrations of spawning Pacific herring (Clupea pallasii) 
and migrating salmonids likely attract seals into San Francisco Bay 
during the winter months (Greig and Allen, 2015). Harbor seals forage 
for Pacific herring in eelgrass beds in the winter (Schaeffer et al., 
2007).
    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). The closest recognized harbor seal pupping site to 
the project is at Castro Rocks, approximately 12 mi (20 km) from the 
project area.

Gray Whale

    In the fall, gray whales migrate from their summer feeding grounds, 
heading south along the coast of North America to spend the winter in 
their breeding and calving areas off the coast of Baja California, 
Mexico. From mid-February to May, the Eastern North Pacific stock of 
gray whales can be seen migrating northward with newborn calves along 
the west coast of the U.S. During the migration, gray whales will 
occasionally enter rivers and bays (such as San Francisco Bay) along 
the coast but not in high numbers. In recent years there have been an 
increased number of gray whales in the San Francisco Bay (W.

[[Page 28774]]

Keener, pers. comm. 2019) and there is an ongoing Unusual Mortality 
Event (https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2021-gray-whale-unusual-mortality-event-along-west-coast-and).

Marine Mammal Hearing

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

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

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

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

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

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far (ANSI 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 impact pile driving and pile removal by underwater chainsaws or 
pile clippers. 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, underwater

[[Page 28775]]

chainsaws, pile clippers, 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).
    One type of pile hammer would be used on this project: impact. 
Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper, 2005).
    Pile clippers and underwater chainsaws are hydraulically operated 
equipment. A pile clipper is a large, heavy elongated horizontal 
guillotine-like structure that is mechanically lowered over a pile down 
to the mudline or substrate where hydraulic force is used to push a 
sharp blade to cut a pile. Sounds generated by this demolition 
equipment are non-impulsive and continuous (NAVAC Southwest, 2020).
    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 
presence of the equipment and personnel; however, any impacts to marine 
mammals are expected to primarily be acoustic in nature. Acoustic 
stressors include effects of heavy equipment operation during pile 
installation and removal.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and the various demolition equipment 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 pile driving and removal and other construction 
noise has the potential to result in auditory threshold shifts and 
behavioral reactions (e.g., avoidance, temporary cessation of foraging 
and vocalizing, changes in dive behavior). Exposure to anthropogenic 
noise can also lead to non-observable physiological responses such an 
increase in stress hormones. Additional noise in a marine mammal's 
habitat can mask acoustic cues used by marine mammals to carry out 
daily functions such as communication and predator and prey detection. 
The effects of pile driving and demolition noise on marine mammals are 
dependent on several factors, including, but not limited to, sound type 
(e.g., impulsive vs. non-impulsive), the species, age and sex class 
(e.g., adult male vs. mom with calf), duration of exposure, the 
distance between the pile and the animal, received levels, behavior at 
time of exposure, and previous history with exposure (Wartzok et al., 
2004; Southall et al., 2007). Here we discuss physical auditory effects 
(threshold shifts) followed by behavioral effects and potential impacts 
on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018), there are numerous factors 
to consider when examining the consequence of TS, including, but not 
limited to, the signal temporal pattern (e.g., impulsive or non-
impulsive), likelihood an individual would be exposed for a long enough 
duration or to a high enough level to induce a TS, the magnitude of the 
TS, time to recovery (seconds to minutes or hours to days), the 
frequency range of the exposure (i.e., spectral content), the hearing 
and vocalization frequency range of the exposed species relative to the 
signal's frequency spectrum (i.e., how animal uses sound within the 
frequency band of the signal; e.g., Kastelein et al., 2014), and the 
overlap between the animal and the source (e.g., spatial, temporal, and 
spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS 2018). Available data from 
humans and other terrestrial mammals indicate that a 40 dB threshold 
shift approximates PTS onset (see Ward et al., 1958, 1959; Ward, 1960; 
Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson 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

[[Page 28776]]

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). The potential for TTS from impact pile driving 
exists. After exposure to playbacks of impact pile driving sounds (rate 
2760 strikes/hour) in captivity, mean TTS increased from 0 dB after 15 
minute exposure to 5 dB after 360 minute exposure; recovery occurred 
within 60 minutes (Kastelein et al., 2016). Additionally, the existing 
marine mammal TTS data come from a limited number of individuals within 
these species. No data are available on noise-induced hearing loss for 
mysticetes. For summaries of data on TTS in marine mammals or for 
further discussion of TTS onset thresholds, please see Southall et al. 
(2007), Finneran and Jenkins (2012), Finneran (2015), and Table 5 in 
NMFS (2018).
    Installing piles requires impact pile driving. 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 pile driving and 
removal also has the potential to behaviorally disturb marine mammals. 
Available studies show wide variation in response to underwater sound; 
therefore, it is difficult to predict specifically how any given sound 
in a particular instance might affect marine mammals perceiving the 
signal. If a marine mammal does react briefly to an underwater sound by 
changing its behavior or moving a small distance, the impacts of the 
change are unlikely to be significant to the individual, let alone the 
stock or population. However, if a sound source displaces marine 
mammals from an important feeding or breeding area for a prolonged 
period, impacts on individuals and populations could be significant 
(e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound 
are highly variable and context-specific and any reactions depend on 
numerous intrinsic and extrinsic factors (e.g., species, state of 
maturity, experience, current activity, reproductive state, auditory 
sensitivity, time of day), as well as the interplay between factors 
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al., 
2007; Weilgart, 2007; Archer et al., 2010). Behavioral reactions can 
vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
In general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. Please see Appendices B and C of Southall et 
al. (2007) for a review of studies involving marine mammal behavioral 
responses to sound.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    In 2016, the Alaska Department of Transportation and Public 
Facilities (ADOT&PF) documented observations of marine mammals during 
construction activities (i.e., pile driving) at the Kodiak Ferry Dock 
(see 80 FR 60636, October 7, 2015). In the marine mammal monitoring 
report for that project (ABR 2016), 1,281 Steller sea lions were 
observed within the Level B disturbance zone during pile driving or 
drilling (i.e., documented as Level B harassment take). Of these, 19 
individuals demonstrated an alert behavior, 7 were fleeing, and 19 swam 
away from the project site. All other animals (98 percent) were engaged 
in activities such as milling, foraging, or fighting and did not change 
their behavior. In addition, two sea lions approached within 20 m of 
active vibratory pile driving activities. Three harbor seals were 
observed within the disturbance zone during pile driving activities; 
none of them displayed disturbance behaviors. Fifteen killer whales and 
three harbor porpoise were also observed within the Level B harassment 
zone during pile driving. The killer whales were travelling or milling 
while all harbor porpoises were travelling. No signs of disturbance 
were noted for either of these species. Given the similarities in 
activities and habitat, we expect similar behavioral responses of 
marine mammals to the ACOE's specified activity. That is, disturbance, 
if any, is likely to be temporary and localized (e.g., small area 
movements).
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle 1950; Moberg 
2000). In many cases, an animal's first and sometimes most economical 
(in terms of energetic costs) response is behavioral avoidance of the 
potential stressor. Autonomic nervous system responses to stress 
typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg 1987; Blecha 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not

[[Page 28777]]

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 
San Francisco area contains active military and commercial shipping, 
ferry operations, as well as numerous recreational and other commercial 
vessel and background sound levels in the area are already elevated.
    Potential Effects of Underwater Chainsaw and Pile Clipper Sounds--
Underwater chainsaws and pile clippers may be used to assist with 
removal of piles. The sounds produced by these activities are of 
similar frequencies to the sounds produced by vessels (NAVFAC 
Southwest, 2020), and are anticipated to diminish to background noise 
levels (or be masked by background noise levels) in San Francisco Bay 
relatively close to the project site. Therefore, the effects of this 
equipment are likely to be similar to those discussed above in the 
Behavioral Harassment section.
    Airborne Acoustic Effects--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal that have the potential to cause behavioral harassment, 
depending on their distance from pile driving activities. Cetaceans are 
not expected to be exposed to airborne sounds that would result in 
harassment as defined under the MMPA.
    Airborne noise would primarily be an issue for pinnipeds that are 
swimming or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. We recognize that 
pinnipeds in the water could be exposed to airborne sound that may 
result in behavioral harassment when looking with their heads above 
water. Most likely, airborne sound would cause behavioral responses 
similar to those discussed above in relation to underwater sound. For 
instance, anthropogenic sound could cause hauled-out pinnipeds to 
exhibit changes in their normal behavior, such as reduction in 
vocalizations, or cause them to temporarily abandon the area and move 
further from the source. However, these animals would likely previously 
have been `taken' because of exposure to underwater sound above the 
behavioral harassment thresholds, which are generally larger than those 
associated with airborne sound. Thus, the behavioral harassment of 
these animals is already accounted for in these estimates of potential 
take. Therefore, we do not believe that authorization of incidental 
take resulting from airborne sound for pinnipeds is warranted, and 
airborne sound is not discussed further here.

Marine Mammal Habitat Effects

    The 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 impact and vibratory pile driving 
or removal, elevated levels of underwater noise would ensonify 
Richardson's and San Francisco Bay where both fishes and mammals occur 
and could affect foraging success. Additionally, marine mammals may 
avoid the area during construction, however, displacement due to noise 
is expected to be temporary and is not expected to result in long-term 
effects to the individuals or populations. Construction activities are 
of short duration and would likely have temporary impacts on marine 
mammal habitat through increases in underwater and airborne sound.
    A temporary and localized increase in turbidity near the seafloor 
would occur in the immediate area surrounding the area where piles are 
installed or removed. In general, turbidity associated with pile 
installation is localized to about a 25-foot (7.6-m) radius around the 
pile (Everitt et al. 1980). The sediments of the project site are sandy 
and will settle out rapidly when disturbed. Cetaceans are not expected 
to be close enough to the pile driving areas to experience effects of 
turbidity, and any pinnipeds could avoid localized areas of turbidity. 
Local strong currents are anticipated to disburse any additional 
suspended sediments produced by project activities at moderate to rapid 
rates depending on tidal stage. Therefore, we expect the impact from 
increased turbidity levels

[[Page 28778]]

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., the impacted area is mostly in 
Richardson's Bay only) of San Francisco Bay and does not include any 
Biologically Important Areas or other habitat of known importance. The 
area is highly influenced by anthropogenic activities. The total 
seafloor area affected by pile installation and removal is a very small 
area compared to the vast foraging area available to marine mammals in 
San Francisco Bay. At best, the impact area provides marginal foraging 
habitat for marine mammals and fish. Furthermore, pile driving and 
removal 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 pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity.
    In-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).
    Because of the rarity of use and research, the effects of pile 
clippers and underwater chainsaws are not fully known; but given their 
similarity to ship noises we do not expect unique effects from these 
activities.
    The most likely impact to fish from pile driving and removal and 
demolition 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 forage fish in the project area. 
Forage fish form a significant prey base for many marine mammal species 
that occur in the project area. Increased turbidity is expected to 
occur in the immediate vicinity (on the order of 10 feet (3 m) or less) 
of construction activities. However, suspended sediments and 
particulates are expected to dissipate quickly within a single tidal 
cycle. Given the limited area affected and high tidal dilution rates 
any effects on forage fish are expected to be minor or negligible. 
Finally, exposure to turbid waters from construction activities is not 
expected to be different from the current exposure; fish and marine 
mammals in San Francisco Bay are routinely exposed to substantial 
levels of suspended sediment from natural and anthropogenic sources.
    In summary, given the short daily duration of sound associated with 
individual pile driving events and the relatively small areas being 
affected, pile driving activities associated with the proposed action 
are not likely to have a permanent, adverse effect on any fish habitat, 
or populations of fish species. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity. Thus, we 
conclude that impacts of the specified activity are not likely to have 
more than short-term adverse effects on any prey habitat or populations 
of prey species. Further, any impacts to marine mammal habitat are not 
expected to result in significant or long-term consequences for 
individual marine mammals, or to contribute to adverse impacts on their 
populations.

Estimated Take

    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

[[Page 28779]]

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., vibratory or impact pile driving) has the 
potential to result in disruption of behavioral patterns for individual 
marine mammals. There is also some potential for auditory injury (Level 
A harassment) to result for pinnipeds and harbor porpoise because 
predicted auditory injury zones are larger. 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 above which 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, NMFS relied on local occurrence data and group 
size to estimate take for some species. Below, we describe the factors 
considered here in more detail and present the proposed take estimate.

Acoustic Thresholds

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

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

Ensonified Area

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

[[Page 28780]]

the project (i.e., impact pile driving, pile clippers and underwater 
chainsaws).
    In order to calculate distances to the Level A harassment and Level 
B harassment sound thresholds for the methods and piles being used in 
this project, NMFS used acoustic monitoring data from other locations 
to develop source levels for the various pile types, sizes and methods 
(see Table 5). Data for the pile clippers and underwater chainsaws come 
from data gathered at U.S. Navy projects in San Diego Bay (NAVFAC SW, 
2020), the source levels used are from the averages of the maximum 
source levels measured, a somewhat more conservative measure than the 
median sound levels we typically use. The source level for an 
underwater chainsaw is 150 db RMS and the source level for a large pile 
clipper is 161 dB RMS (NAVFAC SW, 2020). Because the ACOE's as yet 
unhired contractor has not decided which of the various pile removal 
methods it will use, we only use a worst-case scenario of operation 
using the loudest sound producing method (large pile clippers) to 
consider the largest possible harassment zones and estimated take.

                                      Table 5--Project Sound Source Levels
----------------------------------------------------------------------------------------------------------------
               Method                       Pile type         Estimated noise level             Source
----------------------------------------------------------------------------------------------------------------
Cutting............................  18-inch concrete......  161 dB RMS............  NAVFAC SW 2020.
Cutting............................  14-inch timber........  161 dB RMS............  NAVFAC SW 2020.
Impact Driving.....................  24-inch concrete......  159 dB SEL, 184 dB      Illingworth and Rodkin,
                                                              Peak.                   Inc., 2019.
Impact Driving.....................  14-inch timber........  155 dB SEL, 175 dB      Table I.2-3 (CalTrans
                                                              Peak.                   2015).
----------------------------------------------------------------------------------------------------------------
Note: SEL = single strike sound exposure level; dB Peak = peak sound level; RMS = root mean square. Impact
  driving source levels reduced by 5 dB to account for use of bubble curtain.

Level B Harassment Zones

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

TL = B * Log10 (R1/R2),

    where

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

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, which is the most appropriate 
assumption for the ACOE's proposed activity in the absence of specific 
modelling.
    The ACOE determined underwater noise would fall below the 
behavioral effects threshold of 160 dB RMS for impact driving at 22 m 
and the 120 dB rms threshold for pile cutting at 5,412 m. It should be 
noted that based on the bathymetry and geography of San Francisco Bay, 
sound will not reach the full distance of the Level B harassment 
isopleths in all directions.

Level A Harassment Zones

    When the NMFS Technical Guidance (2016) was published, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of take by Level A harassment. However, these tools offer 
the best way to predict appropriate isopleths when more sophisticated 
3D modeling methods are not available, and NMFS continues to develop 
ways to quantitatively refine these tools, and will qualitatively 
address the output where appropriate. For stationary sources such as 
impact pile driving or removal using any of the methods discussed 
above, NMFS User Spreadsheet predicts the closest distance at which, if 
a marine mammal remained at that distance the whole duration of the 
activity, it would not incur PTS. We used the User Spreadsheet to 
determine the Level A harassment isopleths. Inputs used in the User 
Spreadsheet or models are reported in Table 1 and the resulting 
isopleths are reported in Table 6 for each of the construction methods 
and pile types.

                                      Table 6--Level A and Level B Isopleths (Meters) for Each Pile Type and Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Low-frequency   Mid-frequency   High-frequency
                Method                         Pile type            cetaceans       cetaceans        cetaceans       Phocids      Otariids     Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cutting..............................  18-inch concrete........               6             0.5               8.9          3.7          0.3         5412
Cutting..............................  14-inch timber..........               6             0.5               8.9          3.7          0.3         5412
Impact Driving.......................  24-inch concrete........           116.4             4.1             138.7         62.3          4.5           22
Impact Driving.......................  14-inch timber..........              63             2.2              75.1         33.7          2.5           22
--------------------------------------------------------------------------------------------------------------------------------------------------------

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. Here we describe how the information provided above is 
brought together to produce a quantitative take estimate.

Bottlenose Dolphin

    Density data for this species in the project vicinity do not exist. 
San Francisco Oakland Bay Bridge (SFOBB) project monitoring showed two 
observations of this species over 6 days of monitoring in 2017 
(CalTrans 2018). One common bottlenose dolphin is sighted with 
regularity near Alameda (GGCR 2016). Based on the regularity of the 
sighting in Alameda and the SFOBB

[[Page 28781]]

observations of approximately 0.33 dolphin a day, we propose the Level 
B harassment take equivalent to 0.33 dolphins per day for the 26 
proposed days of the project, or 9 common bottlenose dolphin (Table 70. 
Because the Level A harassment zones are relatively small and we 
believe the Protected Species Observer (PSO) will be able to 
effectively monitor the Level A harassment zones, we do not anticipate 
or propose take by Level A harassment of bottlenose dolphins.

Harbor Porpoise

    Density data for this species from SFOBB monitoring was 0.17/km\2\ 
(CalTrans 2018). Based on the different pile types and methods there 
are three different sized ensonified areas to be considered to estimate 
Level B harassment take (Table 8). Multiplication of the above density 
times the corresponding ensonified area and duration, summing the 
results for the three methods, and subtracting the overlap of Level A 
take (below) to avoid double-counting of take, leads to a proposed 
Level B harassment take of 21 harbor porpoise (Table 7).
    Similarly, calculating expected Level A harassment take as density 
times the corresponding Level A harassment ensonified area and duration 
for each method results in an estimate that less than one harbor 
porpoise may enter a Level A harassment zone during the project (see 
Table 14 of application). Given the relatively high density and larger 
size of the Level A isopleths for harbor porpoises (Table 6, high-
frequency cetaceans) we consider Level A harassment take is a 
possibility. However, we recognize that harbor porpoises travel in 
groups of up to 10 individuals and can be quick and somewhat cryptic, 
so there is potential that underwater mammals may go undetected before 
spotted in the Level A harassment and shutdown zone. Based on this 
observation we propose Level A harassment take of 2 harbor porpoise.

California Sea Lion

    Density data for this species from SFOBB monitoring was 0.16/km\2\ 
(CalTrans 2018). Based on the different pile types and methods there 
are three different sized ensonified areas to be considered to estimate 
Level B harassment take (Table 8). Multiplication of the above density 
times the corresponding ensonified area and duration, and summing the 
results for the three methods, and subtracting the overlap of Level A 
take (below) to avoid double-counting of take, leads to a proposed 
Level B harassment take of 20 California sea lions (Table 7).
    Similarly, calculating expected Level A harassment take as density 
times the corresponding Level A harassment ensonified area and duration 
for each method results in an estimate that less than one California 
sea lion will enter a Level A harassment zone (see Table 13 of 
application). Given the relatively high density and behavior of 
California sea lions we consider Level A harassment take is a 
possibility. Based on this observation we propose Level A harassment 
take of 2 California sea lions.

Northern Fur Seal

    Density data for this species in the project vicinity do not exit. 
SFOBB monitoring showed no observations of this species (CalTrans 
2018). None were observed for the Treasure Island Ferry Dock project in 
2019 (Matt Osowski, personal communication). The Marine Mammal Center 
rescues about five northern fur seals in a year, and they occasionally 
rescue them from Yerba Buena Island and Treasure Island (TMMC, 2019). 
To be conservative we propose Level B harassment take of three northern 
fur seals. Because the Level A harassment zones are relatively small 
and we believe the Protected Species Observer (PSO) will be able to 
effectively monitor the Level A harassment zones, and the species is 
rare, we do not anticipate or propose take by Level A harassment of 
northern fur seals.

Northern Elephant Seal

    Density data for this species in the project vicinity do not exist. 
SFOBB monitoring showed no observations of this species (CalTrans 
2018). None were observed for the Treasure Island Ferry Dock project in 
2019 (Matt Osowski, personal communication). Out of the approximately 
100 annual northern elephant seal strandings in San Francisco Bay, 
approximately 10 individuals strand nearby at Yerba Buena or Treasure 
Islands each year (TMMC, 2020). Therefore, we propose the Level B 
harassment take of 5 northern elephant seals. Because the Level A 
harassment zones are relatively small and we believe the PSO will be 
able to effectively monitor the Level A harassment zones, and the 
species is rare, we do not anticipate or propose take by Level A 
harassment of northern elephant seals.

Harbor Seal

    Density data for this species from SFOBB monitoring was 3.92/km\2\ 
(CalTrans 2018). Based on the different pile types and methods there 
are three different sized ensonified areas to be considered to estimate 
Level B harassment take (Table 8). Multiplication of the above density 
times the corresponding ensonified area and duration, summing the 
results for the three methods, and subtracting the overlap of Level A 
take (below) to avoid double-counting of take, leads to a proposed 
Level B harassment take of 527 harbor seals (Table 7).
    Similarly, calculating expected Level A harassment take as density 
times the corresponding Level A harassment ensonified area and duration 
for each method results in an estimate that less than one harbor seal 
may enter a Level A harassment zone during the project (see Table 12 of 
application). Given the relatively high density and size of the Level A 
isopleths for harbor seals (Table 6, phocid pinnipeds) we consider 
Level A harassment take is a possibility. We recognize that harbor 
seals can occur in moderate and rarely large size groups and can be 
quick and somewhat cryptic, so there is potential that underwater 
mammals may go undetected before spotted in the Level A harassment and 
shutdown zone. Based on this observation we propose Level A harassment 
take of 2 harbor seals.

Gray Whale

    Density data for this species in the project vicinity do not exist. 
SFOBB monitoring showed no observations of this species (CalTrans 
2018). None were observed for the Treasure Island Ferry Dock project in 
2019 (Matt Osowski, personal communication). Approximately 12 gray 
whales were stranded in San Francisco Bay from January to May of 2019 
(TMMC, 2019) and four stranded in the vicinity on one week in 2021 
(https://www.washingtonpost.com/science/2021/04/11/whales-sf-bay-beaches/). Because recent observations are not well understood, 
Sausalito sits near the entrance to the bay, and as a conservative 
measure, we propose Level B harassment take of 2 gray whales. Because 
the Level A harassment zones are relatively small and we believe the 
PSO will be able to effectively monitor the Level A harassment zones, 
and the species is rare, we do not anticipate or propose take by Level 
A harassment of gray whales.

[[Page 28782]]



   Table 7--Proposed Authorized Amount of Taking, by Level A Harassment and Level B Harassment, by Species and
                                       Stock and Percent of Take by Stock
----------------------------------------------------------------------------------------------------------------
                                                                    Level A         Level B
         Common name          Scientific name       Stock         harassment      harassment    Percent of stock
----------------------------------------------------------------------------------------------------------------
Harbor seal.................  (Phoca           California                    2             527               1.7
                               vitulina).       Stock.
Harbor porpoise.............  (Phocoena        San Francisco--               2              21               0.3
                               phocoena).       Russian River
                                                Stock.
California sea lion.........  (Zalophus        U.S. Stock.....               2              20              <0.1
                               californianus).
Gray whale..................  (Eschrichtius    Eastern North                 0               2              <0.1
                               robustus).       Pacific Stock.
Bottlenose dolphin..........  (Tursiops        California                    0               9                 2
                               truncatus).      Coastal Stock.
Northern elephant seal......  (Mirounga        California                    0               5              <0.1
                               angustirostris   Breeding Stock.
                               ).
Northern fur seal...........  (Callorhinus     California and                0               3              <0.1
                               ursinus).        Eastern North
                                                Pacific Stocks.
----------------------------------------------------------------------------------------------------------------


                            Table 8--Calculations To Estimate Level B Harassment Take
----------------------------------------------------------------------------------------------------------------
                                                                                                      Harbor
                                                                    Harbor seal      Sea lion        porpoise
----------------------------------------------------------------------------------------------------------------
SFOBB Species density (animals/square kilometer (km\2\))........            3.96            0.16            0.17
Days of Pile Driving/Cutting:
    24-inch Concrete............................................              10              10              10
    14-inch Timber..............................................               6               6               6
    Pile Cutting................................................              10              10              10
Area of Isopleth in km\2\:
    24-inch Concrete............................................         0.00151         0.00151         0.00151
    14-inch Timber..............................................         0.00151         0.00151         0.00151
    Pile Cutting................................................         13.3456         13.3456         13.3456
Per day take Level B:
    24-inch Concrete............................................           0.006          0.0002          0.0003
    14-inch Timber..............................................           0.006          0.0002          0.0003
    Pile Cutting................................................         52.8486          2.1353          2.2688
                                                                 -----------------------------------------------
        Total Level B Take Calculated...........................          528.58           21.36           22.69
                                                                 -----------------------------------------------
        Total Level B Take Estimated............................             529              22              23
----------------------------------------------------------------------------------------------------------------

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, 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:
     Avoid direct physical interaction with marine mammals 
during construction activity. If a marine mammal comes within 10 m of 
such activity, operations must cease and vessels must reduce speed to 
the minimum level required to maintain steerage and safe working 
conditions;
     Conduct training between construction supervisors and 
crews and the marine mammal monitoring team and relevant ACOE staff 
prior to the start of all pile driving activity and when new personnel 
join the work, so that responsibilities, communication procedures, 
monitoring protocols, and operational procedures are clearly 
understood;
     Pile driving activity must be halted upon observation of 
either a species for which incidental take is not authorized or a 
species for which incidental take has been authorized but the 
authorized number of takes has been met, entering or within the 
harassment zone;
     The ACOE will establish and implement the shutdown zones 
indicated in Table 9. The purpose of a shutdown zone is generally to 
define an area within which shutdown of the activity would occur upon 
sighting of a marine mammal (or in anticipation of an animal entering 
the defined area). Shutdown zones typically vary based on the activity 
type and marine mammal

[[Page 28783]]

hearing group. The ACOE wishes to simplify implementation of the 
relatively small shutdown zones and has proposed using a single 
shutdown zone distance for each activity rather than separate zones for 
each hearing group as we minimally require typically. Therefore the 
shutdown zones in Table 9 are based on the largest possible Level A 
harassment zones calculated from the isopleths in Table 6.
     Employ PSOs and establish monitoring locations as 
described in the application and Section 5 of the IHA. The Holder must 
monitor the project area to the maximum extent possible based on the 
required number of PSOs, required monitoring locations, and 
environmental conditions For all pile driving and removal one PSO must 
be used. The PSO will be stationed as close to the activity as 
possible;
     The placement of the PSO during all pile driving and 
removal and drilling activities will ensure that the entire shutdown 
zone is visible during pile installation. Should environmental 
conditions deteriorate such that marine mammals within the entire 
shutdown zone will not be visible (e.g., fog, heavy rain), pile driving 
and removal must be delayed until the PSO is confident marine mammals 
within the shutdown zone could be detected;
     Monitoring must take place from 30 minutes prior to 
initiation of pile driving activity through 30 minutes post-completion 
of pile driving activity. Pre-start clearance monitoring must be 
conducted during periods of visibility sufficient for the lead PSO to 
determine the shutdown zones clear of marine mammals. Pile driving may 
commence following 30 minutes of observation when the determination is 
made;
     If pile driving is delayed or halted due to the presence 
of a marine mammal, the activity may not commence or resume until 
either the animal has voluntarily exited and been visually confirmed 
beyond the shutdown zone or 15 minutes have passed without re-detection 
of the animal;
     The ACOE must use soft start techniques when impact pile 
driving. Soft start requires contractors to provide an initial set of 
three strikes at reduced energy, followed by a 30-second waiting 
period, then two subsequent reduced-energy strike sets. A soft start 
must be implemented at the start of each day's impact pile driving and 
at any time following cessation of impact pile driving for a period of 
30 minutes or longer;
     Use a bubble curtain during impact pile driving and ensure 
that it is operated as necessary to achieve optimal performance, and 
that no reduction in performance may be attributable to faulty 
deployment. At a minimum, the ACOE must adhere to the following 
performance standards: The bubble curtain must distribute air bubbles 
around 100 percent of the piling circumference for the full depth of 
the water column. The lowest bubble ring must be in contact with the 
substrate for the full circumference of the ring, and the weights 
attached to the bottom ring shall ensure 100 percent substrate contact. 
No parts of the ring or other objects shall prevent full substrate 
contact. Air flow to the bubblers must be balanced around the 
circumference of the pile.

     Table 9--Shutdown Zones (Meters) for Each Pile Type and Method
------------------------------------------------------------------------
                                                                Shutdown
                 Pile size, type, and method                      zone
------------------------------------------------------------------------
24-inch concrete, impact.....................................        140
14-inch timber, impact.......................................         80
14 and 18-inch pile cutting..................................         10
------------------------------------------------------------------------

    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

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

Visual Monitoring

     Monitoring must be conducted by qualified, NMFS-approved 
PSOs, in accordance with the following: PSOs must be independent (i.e., 
not construction personnel) and have no other assigned tasks during 
monitoring periods. At least one PSO must have prior experience 
performing the duties of a PSO during construction activity pursuant to 
a NMFS-issued incidental take authorization. Other PSOs may substitute 
other relevant experience, education (degree in biological science or 
related field), or training. PSOs must be approved by NMFS prior to 
beginning any activity subject to this IHA.
     PSOs must record all observations of marine mammals as 
described in the Section 5 of the IHA, regardless of distance from the 
pile being driven. PSOs shall document any behavioral reactions in 
concert with distance from piles being driven or removed;
    PSOs must have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;

[[Page 28784]]

     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary;
     The ACOE must establish the following monitoring 
locations. For all pile driving and cutting activities, a minimum of 
one PSO must be assigned to the active pile driving or cutting location 
to monitor the shutdown zones and as much of the Level B harassment 
zones as possible.

Reporting

    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities, or 60 days prior to a requested date of issuance of any 
future IHAs for projects at the same location, whichever comes first. 
The report will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact or cutting) and the total 
equipment duration for cutting for each pile or total number of strikes 
for each pile (impact driving);
     PSO locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information: Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting; Time of sighting; Identification of the 
animal(s) (e.g., genus/species, lowest possible taxonomic level, or 
unidentified), PSO confidence in identification, and the composition of 
the group if there is a mix of species; Distance and bearing of each 
marine mammal observed relative to the pile being driven for each 
sighting (if pile driving was occurring at time of sighting); Estimated 
number of animals (min/max/best estimate); Estimated number of animals 
by cohort (adults, juveniles, neonates, group composition, etc.); 
Animal's closest point of approach and estimated time spent within the 
harassment zone; Description of any marine mammal behavioral 
observations (e.g., observed behaviors such as feeding or traveling), 
including an assessment of behavioral responses thought to have 
resulted from the activity (e.g., no response or changes in behavioral 
state such as ceasing feeding, changing direction, flushing, or 
breaching);
     Number of marine mammals detected within the harassment 
zones, by species; and
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting changes in behavior of the 
animal(s), if any.
    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.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the IHA-holder must 
immediately cease the specified activities and report the incident to 
the Office of Protected Resources (OPR) 
([email protected]), NMFS and to West Coast 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).
    Pile driving and removal activities have the potential to disturb 
or displace marine mammals. Specifically, the project activities may 
result in take, in the form of Level A and Level B harassment from 
underwater sounds generated from pile driving and removal. Potential 
takes could occur if individuals are present in the ensonified zone 
when these activities are underway.
    The takes from Level A and Level B harassment would be due to 
potential behavioral disturbance, TTS, and PTS. No mortality is 
anticipated given the

[[Page 28785]]

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).
    The Level A harassment zones identified in Table 6 are based upon 
an animal exposed to impact pile driving multiple piles per day. 
Considering duration of impact driving each pile (up to 20 minutes) and 
breaks between pile installations (to reset equipment and move pile 
into place), this means an animal would have to remain within the area 
estimated to be ensonified above the Level A harassment threshold for 
multiple hours. This is highly unlikely given marine mammal movement 
throughout the area. If an animal was exposed to accumulated sound 
energy, the resulting PTS would likely be small (e.g., PTS onset) at 
lower frequencies where pile driving energy is concentrated, and 
unlikely to result in impacts to individual fitness, reproduction, or 
survival.
    The nature of the pile driving project precludes the likelihood of 
serious injury or mortality. For all species and stocks, take would 
occur within a limited, confined area (north-central San Francisco Bay 
including Richardson's Bay) of the stock's range. Level A and Level B 
harassment will be reduced to the level of least practicable adverse 
impact through use of mitigation measures described herein. Further the 
amount of take proposed to be authorized is extremely small when 
compared to stock abundance.
    Behavioral responses of marine mammals to pile driving 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) 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 and that pile driving and removal would 
occur across nine months, 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;
     Authorized Level A harassment would be very small amounts 
and of low degree;
     No important habitat areas have been identified within the 
project area;
     For all species, San Francisco Bay is a very small and 
peripheral part of their range'
     The ACOE would implement mitigation measures such as 
bubble curtains, soft-starts, and shut downs; and
     Monitoring reports from similar work in San Frnacisco Bay 
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 as the 
temporal or spatial scale of the activities.
    The amount of take NMFS proposes to authorize is below one third of 
the estimated stock abundance of all species (in fact, take of 
individuals is less than 10 percent of the abundance of the affected 
stocks, see Table 7). This is likely a conservative estimate because 
they assume all takes are of different individual animals which is 
likely not the case. Some individuals may return multiple times in a 
day, but PSOs would count them as separate takes if they cannot be 
individually identified.
    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

    Section 7(a)(2) of the 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 Debris Dock Replacement project 
in Sausalito, CA from September 1, 2021 through August 31, 2022, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. A draft of the proposed IHA can be found 
at https://

[[Page 28786]]

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 Debris 
Dock Replacement 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 Description of Proposed 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a Renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that 
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 25, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-11333 Filed 5-27-21; 8:45 am]
BILLING CODE 3510-22-P